Diesel vs. Mogas

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Last month, on the drive from our hotel in Austria to the Aero exposition halls in Friedrichshafen, the route carried us over a stretch of one of those famous autobahns with no speed limit. Actually, it may have had a posted limit, but no one was paying any attention to it. I wound up our little Ford Ka rental to a blistering 162 Kph—about 100 MPH, a speed at which it's not terribly confidence inspiring.

As is common in Europe, I looked in the rearview mirror to see a pair of headlights closing at the speed of heat. It was a Mercedes turbodiesel that swished by doing probably 230. It was out of sight in 20 seconds. You see a lot of this in Germany because Germans like their high-performance cars and they like economy, too. It wouldn't surprise me if the Merc was making 30 MPG even at that speed.

In Europe, diesels have about 53 percent of the automotive market, so the fact that this technology migrated to airplanes, first by Thielert and now by Austro, was inevitable. Diamond didn't push diesel sales in the U.S. because it felt U.S. buyers don't get—or at least don't want—diesel engines in cars or airplanes. (Boats and trucks are another matter.) One comment on our Austro factory tour video summed it up: "408 pounds; 168 HP. No thanks."

This is a fairly typical diesel prejudice not entirely without merit, but also likely ignorant of careful analysis. On paper, both the Thielert and Austro diesels have several factors going against them. The big one for Austro is weight, but that's an issue with Thielert, too. Second, they have gearboxes. It's not like reduction gearboxes haven't been successful in airplanes and going way back, too. The Rolls Royce Merlin had a gearbox. So do many radial engines. It's just that for light aircraft, gear trains have had a checkered history and the truly bulletproof light GA engines have tended to be direct drive. Last, diesel engines generate strong torque pulses that are hard on props, requiring either a clutch (Thielert) or a torsional damper (Austro).

Thielert attacked the weight problem by recasting the basic Daimler-Benz four-cylinder diesel it used as a core in aluminum, a decision which brought its own problems. Austro, on the other hand, stuck with Daimler's original cast iron as a tradeoff for durability, leaving it up to the airframer to certify at a higher weight and reduce empty weight. (Diamond did both, cancelling out much of the Austro's higher weight for its diesel twins.)

In general, the diesels have been more expensive to buy, have shorter overhaul periods and have periodic component inspections that are a nuisance. Furthermore, Jet A is only a bit cheaper than avgas and in some places, it's more expensive. So you add all this up, and the diesel is doomed, right? Well, it would be save for one simple fact: Diesels are more economical than gasoline engines by a margin great enough to more than offset those disadvantages. I've interviewed a number of Thielert owners, reviewed their numbers and sure enough, even with all the troubles Thielert has been through, they still come out even or a bit ahead against a gasoline engine. As diesels mature, the trend line moves more in the diesel's favor.

Here's a simple example. A 180-HP parallel valve O-360 costs about $20,000 to overall, with a 2000-hour TBO and burning about 9 GPH, block to block. Using $6.04 avgas, the hourly operating cost is $54.36 for fuel and $10 for the engine reserve.

Compare that to the Austro, which costs about the same to overhaul—actually, at $19,400, a little less. (It's not clear to me if this is loss-leader pricing. I'm plugging in the numbers Austro gave me.) The engine burns about 6.5 GPH of $5.65 Jet A for an hourly of $36.72 for fuel and $16 for the engine reserve for a total of $52.72. That's $11.64 an hour less than the gasoline engine. Not impressed? Me, neither, because over the life of engine, that's about $14,000 in savings, a portion of which will be chewed up by the required inspections and component replacements. (To be fair, the Lycoming will have some of those expenses, too.)

But here's where the diesel turns a big corner. Diesels are traditionally high durability engines and Austro would like to get the TBO to 2700 hours. If they succeed, the engine reserve drops to $7 and the hourly goes to $43.90 against the gasoline engine's $64. Over the 2000-hour run of both engines, that's $40,000 less and that ain't chump change for a flight school, which is where many of these airplanes are used. The Thielert numbers aren't as favorable because at 1500 hours, it has to be replaced at a cost of $42,000, but the directionality is the same. At 2000 hours, the Austro reserve goes to $9.70, but it still comes out ahead of the gas engine.

The numbers above reflect U.S. fuel prices. In Europe, the equation favors diesel more strongly because avgas is so expensive. Jet A is about 18 percent cheaper than avgas in Europe. In the U.S. the Delta is about 6 percent.

Mogas is a field leveler both in Europe, where it's more common, and in the U.S., if it can gain a meaningful market foothold. In the U.S., according to AirNav's surveys, mogas averages $4.62 when dispensed at an airport. That's about $1.40 less than avgas. Plugged into the model above, the 2000-hour life cycle savings for mogas against avgas would amount to $25,600—basically the cost of an engine overhaul and then some. Not bad, albeit not quite as efficient as the diesel.

On the other hand, if the 180-HP power band is framed as mogas against diesel, you could argue the two are about equal in the U.S. Although the diesel still enjoys a slightly lower life-cycle fuel cost, its inspections and component replacements can eat that up. In Europe, mogas ranges from $7 to $9, while Jet A is $7 to $10.50 Where the prices are the same, the diesel enjoys a huge advantage in overall cost. If the spread is $3 in favor of mogas, the mogas engine wins, but by a smaller margin because it burns more.

So where does this leave the aerodiesel market? It's a good question that no one can really answer. Thus far, diesels have gained a foothold—just. Thielert has manufactured about 2600 engines and Austro about 450. Diamond is the only OEM to bet big on diesel, with the Austro investment—both because of economy and fuel availability. Looking eastward into Russia and Asia, Diamond is looking for a world fuel. Jet A is definitely it; mogas might be; avgas definitely isn't. Diamond doesn't think mogas will be a player on airports in Russia and eastward.

Continental is covering the board with a couple of new engines approved for mogas, but also an emerging diesel project. Lycoming is bearish on diesel and has aggressively pursued low-octane approvals for many of its engines, albeit not exactly mogas, but a lower-octane aviation fuel. With its new 912 iS, Rotax remains firmly in the gasoline camp, with engines approved for mogas up to E10. The 912 iS is fuel-efficient enough on gasoline that I doubt anyone will bother with a small horsepower diesel.

The major inflection point will come in the high-horsepower market—the 300-HP engines and higher used in airplanes such as the Cirrus and Cessna's heavier models. It seems unlikely that mogas will be a player here and when I say mogas, I'm excluding low-octane alkylate-based offerings like Total's new 91UL. So the visible choices may be the elusive replacement for 100LL or Jet A/diesel. Since I think the likelihood of an affordable, economical turbine is about zero, that leaves a Jet A burning piston with 300 or more horsepower.

Austro is working on this very thing in conjunction with Eurocopter. The AE440, a 400-HP plus V-8. Austro's timeline on this is about a decade, at which point it sees a market gap opening. Besides the large lump of capital required, the biggest challenge will be weight. The under 200-HP diesel represents a power-to-weight sweet spot; as diesels get more powerful, they also get heavier and at some point, they're just too heavy to work no matter what their power output. (Pipistrel, of course, took the tack of developing a low-drag airframe that requires a small displacement gasoline engine that can operate on mogas. But the airplane is some distance from having market impact.)

Where this is going is anyone's guess. The diesel numbers hold up to short-term scrutiny, but the technology just doesn't have enough field experience to prove itself long term. Austro has inarguably proved that the engines aren't too heavy to perform well. Mogas suffers from some of the same ill-informed prejudices that diesel does, but neither it nor diesel are igniting a wild-eyed buying frenzy. As for avgas, well, who the hell knows? All we get are bland and vague assurances that a replacement will be there. Not exactly the stuff of confidence building.

My guess is that a fragmented mix will emerge, dominated by avgas engines for another five to 10 years, with diesel and mogas powerplants grabbing a slice of the market. If you believe in the economy of scale holding prices down, that may not bode well for either diesel or mogas making a dent in the universe quickly, as Steve Jobs used to say. That's especially true if you're an airport operator trying to maintain three fuel systems in a declining market.

Comments (111)

This is a well-balanced summary of things, thanks Paul. A few comments - lighter aircraft in the European UL and US LSA class are very sensitive to engine weight due to gross weight limitations. This favors mogas engines over diesel. The great success of the Rotax engine, even now in the U.S., shows that pilots are comfortable flying with reduction gears as the Rotax uses. On high-power engines, Lycoming's 350 HP TEO-540-A1A is said to operate on 93AKI mogas, according to Tecnam officials who will use the engine in their 11-seat twin P2012.

Posted by: Kent Misegades | May 14, 2012 7:25 AM    Report this comment

"That's especially true if you're an airport operator trying to maintain three fuel systems in a declining market."

I doubt we'll see this in all cases. Even today many FBOs offer only Jet-A or only Avgas or only mogas. They'll offer a third fuel only if it makes economic sense - free markets will figure this all out.

The hammer may fall yet this year on Avgas, since 2012 is the year when Innospec expects the use of TEL for cars to end, dramatically reducing the demand for it. The size of the TEL reserves may just determine how long we'll see Avgas, if Innospec decides to terminate production. I suspect too that we'll see one or more major Avgas producers start to offer mogas in the U.S. as they do in Europe.

Posted by: Kent Misegades | May 14, 2012 7:29 AM    Report this comment

I followed the development of the UK based Powerplant Developments Gemini opposed diesel engines for several years. I was convinced that this engine had merit. It used twin opposed pistons driven by two geared crankshafts in a two-stroke configuration. The Germans used a similar design in the Junkers Jumo 205 engines which did fly. Other opposed piston designs were also used successfully in larger industrial engines.

Unfortunately, the Powerplant Developments effort never resulted in anything substantive although an engine was supposed to be tested in a Tecnam LSA. The smallest 100HP engine might well have given Rotax a run for its money? With the introduction of the new 912iS engine, Rotax will have a winner on its hands for both economic and technical reasons. I'm betting they'll do the same thing to their 914 engines, as well.

MY money is on MoGas, long term.

Posted by: Larry Stencel | May 14, 2012 8:15 AM    Report this comment

Larry - Keep watching also ULPower's mogas engines, air-cooled, direct-drive, FADEC-equipped, they now include a 6-cylinder 200-hp model. Prices make them very competitive with Rotax and they are working on ASTM compliancy to offer them in LSAs.

Posted by: Kent Misegades | May 14, 2012 8:19 AM    Report this comment

Paul asked that I disclose that my business is fuel equipment - I sell Avgas and Jet-A systems for U-Fuel of Elk Mound, WI. These Avgas systems may also be used for mogas, but most airports find spare tanks for mogas and this is not an important market for U-Fuel. I have been an advocate for a multiple fuel solution for many years, stemming from my experiences as a pilot in Germany and as president of EAA1114, one of the largest chapters in the country. We need to lower the cost of flying to keep it vibrant, especially at the low end; using Jet-A diesels and mogas is one means of doing this. But free markets offering multiple fuels are the only real solution to the future of aviation fuels. Let economics work this out depending on local conditions. One size does not fit all. I think that Paul's good article here says just that.

Posted by: Kent Misegades | May 14, 2012 8:39 AM    Report this comment

Good stuff, thanks Kent.

Posted by: Paul Bertorelli | May 14, 2012 8:47 AM    Report this comment

I think the fuel situation will drive the development of new liquid-cooled engine designs, and get us away from the air-cooled dinosaurs. These new engines make high power, but don't use fuel to cool the cylinders so the high octane requirement isn't there. Also, without the need for an open cowling for, the airframe can be cleaned up quite a bit. (gains are partially offset by cutouts for radiators) It's too bad Bombardier quit their V6 aero engine program from a few years ago - that had huge potential IMHO.
One program I've been watching as an engine market analyst is Duke Engines in NZ, who have an interesting axial piston design that's lightweight, thermodynamically efficient and has high power density with multi-fuel capability. Not sure what their funding status is, but hopefully they can come up with the $$ to complete development of their design.

Posted by: Will Alibrandi | May 14, 2012 9:15 AM    Report this comment

All good -- but don't forget that there's a gearbox that needs to be sent back to Europe with some frequency (as little as 300 hours with early Thielerts; now at 1/2 engine TBO) and great expense and inconvenience, unlike the case with direct-drive engines (like most of our venerable gas engines or SMA). There's a significant (but possibly temporary) problem, too: because of the low population and dearth of training, your local shop can't touch your diesel.

Posted by: Tim Kern | May 14, 2012 9:53 AM    Report this comment

Will Piston GA as transportation disappear? I know lots of folks who want Mogas and don't care about the planes using 540/550 engines. They should care. Paul likely knows the numbers, but if you delete these planes from the stats GA quickly becomes a hobby with dwindling infrastructure paying huge fees to do anything more than circle the field.

These planes are what keeps most FBOs open at airports where people want to actually go. They buy most of the fuel. Their owners push or help push the lobbying efforts. There is no Mogas solution for these planes. If they disappear, or go turbine, don't think your precious Mogas will replace 100LL at all the FBOs. Your business will simply not be desirable, or you can pay to park if we have capacity.

Posted by: Eric Warren | May 14, 2012 9:55 AM    Report this comment

Eric, no one fuel solves all needs. Mogas is not for everyone. Air Plains in Wellington, KS is however now testing an IO-540 running mogas with the ADI water injection based on proven WWII technology. If TEL and avgas did suddenly disappear, ADI might keep these planes going forever.
My guess is that we'll follow the trends in Europe - 100LL disappears at airports where there is no demand but remains generally available where it is until these planes are retired or the economics of ADI or a new engine make sense.

Posted by: Kent Misegades | May 14, 2012 10:02 AM    Report this comment

Mark, how about the Australian couple John and Helen Taylor who just got 84 mpg in a stock 2012 VW Passat TDI diesel? Who needs a hybrid or electric with this efficiency?

Posted by: Kent Misegades | May 14, 2012 10:05 AM    Report this comment

Kent, gasoline TDI engines will do roughly the same and preclude the need for finding ultra clean diesel fuel. Personally I would never over inflate the tires or aggressively shift my TDI diesel for such a stunt like the Taylor's did.

Posted by: Mark Fraser | May 14, 2012 10:23 AM    Report this comment

The whole damn thing is rediculuois. The EPA has never and can not prove that lead in the quantities found in the atmosphere has any ill effect on health. They, just like the rest of our Federallis are running amuck.

Posted by: Kent Tarver | May 14, 2012 10:28 AM    Report this comment

First, why do you say no one fuel serves all needs in response to my post?

Second, if water injection with Mogas really does work, then maybe Mogas could replace 100LL. My point is that the solution for high performance planes is all that will actually work in the US.

Lastly, if a European path is your guess, then why try? It's a total failure leading to a place where light planes are just toys with ridiculous costs.

Posted by: Eric Warren | May 14, 2012 10:57 AM    Report this comment

Mark, ULSD fuel is not special - it's been the standard here in the US since 2006, so it's available everywhere. And while the new DI gas engines are very efficient, they don't quite match the economy of a comparable diesel, especially in the larger cars. New diesels run just as clean now as gassers. The EPA's tier 2 bin 5 spec sees to that.

Posted by: Will Alibrandi | May 14, 2012 11:02 AM    Report this comment

Eric, $7+ avgas at many of our airports does not solve the key problem - people are flying less due to fuel costs. Avgas is near impossible to find at any price outside of Europe and N.America, a reason most new piston engines run on mogas or jet fuel. Many engines puke on leaded fuel, ask anyone with a Rotax, auto engine conversion, older low compression engines, etc. You need to attend AERO 2013 to see evidence that GA in Europe is doing quite well. I doubt many Pilatus/TBM/Diamond/Tecnam/Extra owners would agree that their planes are toys. Plus, many of the UL/LSA makers over there are now making four-seaters and twins, have your heard of the new Pipistrel Panthera, hardly a toy. Costs are also far from ridiculous, avgas costs about the same in Europe as it does here, relative to the cost of mogas that people are used to paying in Europe. Plus, what do we do when Innospec stops making TEL?

Posted by: Kent Misegades | May 14, 2012 11:09 AM    Report this comment

Just a few nits from a DA 42 owner (Thielert 2.0 version).

a. Fuel burn is much less than 6.4 gph. At >FL100 fuel burn is less than 5 gph (IAS 130 TAS 150, 70%). This gives a range of about the same as a Mooney M20 at significantly less cost and two-engine safety, and about a third of the operating cost of any other light twin currently available.

b. Comfort. The turbo-diesel engine is quiet and vibration free compared to its Lycoming and Continental brethern. Hardly need ANR headphones.

c. Run-up convenience. I don't know how the FADEC works on the Cirrus, but with the diesel, run-up takes less than a minute per engine and doesn't waste any fuel (you do it on idle power).

d. Jet A is the only fuel available in a growing number of airports, especially in countries where GA is not encouraged.

Posted by: nicholas budd | May 14, 2012 12:22 PM    Report this comment

Any reason that the aircraft diesels cannot eventually be certified to run on automotive diesel? Here in Canada, automotive diesel is about 60% of the price of 100 LL. As I understand it, the standards for automotive diesel have significantly improved with the introduction of the new generation of clean diesel cars.

Posted by: kirk marat | May 14, 2012 5:07 PM    Report this comment

Before we all hold hands to sing Cum-by-yaw in the afterglow of our newfound infatuation with diesel engines running Jet-A, there are a several very significant issues:
1. The largest users of Jet-A, airlines and military have ZERO interest in cetane rating which matters not to Jet engines, but is of considerable importance to high performance diesel engines
2. Jet fuel derived from non petroleum sources has thus far demonstrated very low cetane and lubricating properties, which is mandatory for diesels
3. GA diesels can't count on a stable source of Jet A in it's current form since GA will be such a small segment as compared to the airlines and military
4. As long as there is a market for lead additive, someone will provide the commodity, that's how capitalism works

For the 6 years I've owned my Bonanza the frenzied cry over the death of 100LL and recommending everybody run and hide. This has almost universally been by those who have a financial interest in an alternate fuel type or distribution system. Avgas in 94 - 96 UL will probably be the solution but as yet there isn't any requirement to switch yet.

Posted by: Burns Moore | May 14, 2012 5:19 PM    Report this comment

Fuel here is 5.10 for 100LL.

Europe is a joke and all their ridiculous regulations and fees assures people would rather drive or go commercial. Their planes are essentially toys not due to quality, but because of impracticality. They are really nice toys, but even a 747 is a toy if it's not able to be used properly.

If our pilot population (and worse, owner population) shrinks to the percentage they have it's all over. It will get even more expensive due to lower scale, and then more regulated due to lower political clout.

Which brings me back to my point. If there is no solution for high performance pistons, it's game over. If manufacturing goes off shore, it's all over. The only reason we still don't have user fees is, IIMO, plane manufacturing jobs.

Posted by: Eric Warren | May 14, 2012 6:34 PM    Report this comment

Burns, I have reported on these technical issues previously. My impression is that they are largely a red herring. Last go around, I spent a half week digging into this and the biofuel producers showed cetane ratings in the 40s and 60s. More than high enough for these engines. Ditto for the blends 50/50 Jet A and HRJ and the SPK blends. The new Jet A standards for biofuels and blends cover this, but they don't address cetane.

The more I researched it, the more it sounded like whisper campaign fodder against people who aren't in the diesel camp. The largest issue may be the lack of published standards, not the cetane ratings themselves. I wouldn't dismiss it entirely, but getting reliable, quotable data on it proved elusive. On a scale of the problem index of 10, the life expectancy of leaded fuels is about a 7, cetane for diesels a 2. Diesel has other challenges larger than this.

A while ago, the lawyers at one major, Exxon, decided the company wouldn't sell Jet A for piston aircraft. They eventually relented after some sort of hold harmless agreement and a look at actual technical data. (Imagine that.)

Kirk, Austro and Diamond are looking in certifying for road diesel, which has certified cetane standards. But this has a similar problem as mogas. It would require yet another fuel dispensing system.

Posted by: Paul Bertorelli | May 14, 2012 6:44 PM    Report this comment

Paul - Highway diesel has the additional caveat that, like much of our highway gasoline contains ethanol, it contains a certain percentage of biodiesel. Europeans have been as aggressive in pushing biodiesel as we've been pushing ethanol in this country. I do not know much about issues with biodiesel in aviation though; I suspect it does not absorb water as ethanol does, otherwise I suspect it has some important differences. The comments from DA42 owner Nicholas Budd above are compelling; aviation diesels are clearly worth considering. For the first time I am optimistic about the potential for real efficiency gains as a result of all this and what we saw at AERO. Can't wait to see how Conti's new diesel performs.

Posted by: Kent Misegades | May 14, 2012 7:44 PM    Report this comment

If the Continental solution is an improved version of the SMA disaster, we would be better off with deltahawk. He who replaces the 550 first wins though.

Posted by: Eric Warren | May 14, 2012 8:37 PM    Report this comment

Kudos to Kent for his statement “We need to lower the cost of flying to keep it vibrant, especially at the lower end”. Unfortunately, the politically motivated and self-interested organizations we look to for promoting General Aviation has well organized activity aimed at deflecting away from cost. Silliness as weekly cookouts to “create aviator communities” are supposed to arrest the dwindling number of aviators which most of us know is only due to unjustified and escalating costs at “the lower end”. Another issue that could be of major help for “the lower end” are some guidelines from engine and fuel professionals for a pilot with an engine approaching TBO. Should he do nothing and try to stretch the engine life and is there something that can be done to facilitate this stretch which is not a waste with respect to later full overhaul? What is a pilot’s max. economic exposure if a regular overhaul is done at this time assuming the “least favorable fuel” being the choice? Technical PHD style thesis on fuels and engines are not very helpful to “the lower end” which is really the “kinder garden” and the future of General Aviation. However, observing the self-centered display of short term interests I am not sure anybody cares where “the low end” of General Aviation is ten to twenty years from now.

Posted by: HELGE SKREPPEN | May 14, 2012 9:53 PM    Report this comment

Helge, what we don't need are articles that diesel will greatly lower any costs in light planes. New aircraft will always be out of the reach of normal people (who need homes and medical and family expenses).

A few percentage efficiency is meaningless in the overall equation of PRIVATE aviation. We need cheap, not fancy. That means adapting car engines that are $2K per crate engine. Who cares about a 500-800hr TBO when whole new core gas engines are $2K?

Planes have to take advantage of scale that they don't have. Cars are it, Jet A is not it.

Posted by: Mark Fraser | May 14, 2012 10:08 PM    Report this comment

I, for one plan to fly all electric. I am so over ICE. You will see some technical innovations very soon which will make flying behind an electric powered airplane practical, safe, and range insensitive. Stay tuned.

Posted by: Ed Wahler | May 14, 2012 10:58 PM    Report this comment

The Austro diesel is amazing. Yes, the Thielert version was a dud with ridiculous TBO and quite underpowered, but with the Austro we're turbo-normalized making awesome power at almost all altitudes. To get the same performance from an NA engine, you'd be sucking down 12-15gph per engine. For about the same speed, the fuel consumption of the diesel is about HALF in my experience flying with them. HALF makes a pretty huge difference. It doesn't gobble fuel down at crazy rates during the climb like a regular turbo gas engine either, it's only a few gph more for the "maximum sustainable power". If I had the money, I'd buy a diesel SE plane in a heartbeat over a gas (av, mogas, etc) version. Lycoming and Continental are just lazy and don't want to invest in the future IMO. They quote many reasons why we should continue to use Avgas due to their engine designs, but car engines are way WAY more advanced and if these aviation engine manufacturers could actually look ahead at all, they'd realize they're about to be "jumped" by companies like Austro that are putting the R&D into diesel and products out on the street. Maybe if Lycoming/Conti had done something by now to introduce a reliable high horsepower engine that uses regular auto-fuel (like quite a few car manufacturers have been doing for years) and advanced timing, etc, but they haven't.

Posted by: James Howery | May 14, 2012 11:04 PM    Report this comment

As lame as the alphabets can seem at times, the best use of energy among pilots to reduce the costs is recruiting more pilots. We need VOLUME to get costs down and innovation up. Regulation mostly goes in one direction, fuel prices currently reflect lack of volume and competition.

IMO, all calls for reduced costs by anyone not reducing their own prices should be considered rude and out of line. Enough whinging has gone around. if you can't lower the price yourself, then just deal with it.

If you really love flying, become a part time instructor. Or join EAA and i decrease your cost per hour of aviation fun by building as well as flying. Or get an ultralight. Aviation isn't any more expensive than tennis, it's just that everyone wants to play at the nicer clubs or none at all. That's just sillily.

Posted by: Eric Warren | May 15, 2012 3:40 AM    Report this comment

"Their planes are essentially toys not due to quality, but because of impracticality. "

I think with its DA40/42 line, Diamond would take strong exception to this. Not only are they strong sellers in Europe and the U.S, they claim the best safety record of any GA airplanes ever built, and that's saying something. I was stopped numerous time in Europe by readers and subscribers using airplanes for business and personal transportation throughout Europe. Ditto for Tecnam, for Pipistrel and for others.

To call them toys reflects poorly on us all and shows real ignorance of what's actually happening in the world market.

Posted by: Paul Bertorelli | May 15, 2012 7:24 AM    Report this comment

A few comments here - the Austro folks with whom I spoke described the close work with Mercedes, on whose proven diesel their AE300 is based. That's economy of scale, the same as for diesel/jet/autogas fuels - hoorah! A more efficient diesel engine implies smaller fuel tanks, less fuel weight, balancing the higher engine weight. Some of the criticism of diesels reminds me of the knee-jerk in the U.S. over the Rotax engine, now considered a mainstream engine for nearly all training/LSA aircraft. Let's see where we are with diesels in a few years; all new technology comes at the price of some failures. In their defense, nearly all the engines that Continental and Lycoming showed at AERO run on either autogas or jet fuel. Why they do not stress this more when they appear in the U.S. is odd. Conti used AERO, not Sebring or Sun 'n Fun to debut their O-200-AF autogas-burning engine.

Posted by: Kent Misegades | May 15, 2012 7:30 AM    Report this comment

BTW - at AERO I heard from an Austro engineer that they would have preferred to use a BMW TDI but Damiler was an investor and they were forced to use a Mercedes TDI instead. It would be great to see BMW return to its roots as the company started as an aircraft engine manufacturer, not a car maker. Austro is also working on a large-displacement diesel with famed Austrian engine maker Steyr. Rotax too is based in Austria, a little country with a big heritage in engines.

Posted by: Kent Misegades | May 15, 2012 7:32 AM    Report this comment

Yes, they may be toys in Europe but they are more fun than a bag of titanium golf clubs and green fees high enough to make you weep.
European ultralights (450 kg mtow or 475 with parachute) do not need to fly from registered airfields and can be maintained by anyone, usually the owner.
Rotax cornered the market but are squeezing the orange till the pips squeak, hence ULPower (Volkswagen beetle) and other, interesting half price motors coming along.
Two at least are based on a three cylindre, one litre car engine, originally from Toyota, with electronic engine mapping, which can be modified for aircraft use.
Most use a toothed rubber belt reduction system, good for 100 hours before change.
So far everyone buying one is happy, flying 150kph at 10 litres an hour.
Then there is the Vija, a modified, oil-cooled Suzuki motorbike engine, dating from the early 1990s, with a metal reduction gear, good in standard form for 100 HP.
Again everyone who has had one seems to rave about them.
What is interesting is that they have bolted a turbo onto the standard model and are testing it in a Cessna 152, so far with good results.
We are now in regulated territory so prices will go up, but it stills seems possible to get the Vija in a year or two for the same price as a rebuild of the 1950s lump in the front and then fly on mo-gas with a 40% fuel efficiency saving. more follows..

Posted by: Brian McCulloch | May 15, 2012 8:51 AM    Report this comment

And then finally, a French homebuilder, using a 53HP diesel Peugeot diesel engine from a scrapyard, with no reduction gear,flew his two-seater Gaz'elle from Brittany to Corsica using 51 litres of fuel. That is 1,409 km flown in 7hrs 28 minutes which works out 6.8 litres an hour. Pretty amazing.

Posted by: Brian McCulloch | May 15, 2012 8:51 AM    Report this comment

Kent, let's think this through . . .

Auto manufacturers are very innovative with very rapid advances in equipment and technology and are even quicker to abandon yesterdays engine to be replaced with tomorrows much "better" model. Do you really think MB or BMW will continue to produce parts and support for yesterdays engine in 10 or 20 years? Not even close.

Todays TCM's new balanced flow IO550 will run on 96 UL TODAY, which is our "beloved" 100LL without the Pb and I'm sure Lyc is there as well. That would be my course if I had to replace my Bo's engine today. If we got the DAMN ethanol out of auto gas we'd have lower prices and with FADEC equipment many could run on auto gas today.

I love diesels, my pickup is simple, reliable, efficient and very powerful, and I have used them for personal transportation for 25 years, but they are not a direct replacement for 300HP+ GA engines.

Posted by: Burns Moore | May 15, 2012 8:53 AM    Report this comment

The nice aspect to 96UL is that it can be run through pipelines which, theoretically, should mean lower cost. Ethanol-free avgas would be a nice option to have, but it's not available anywhere near me (CT) as far as I know.

Posted by: Will Alibrandi | May 15, 2012 9:18 AM    Report this comment

"Do you really think MB or BMW will continue to produce parts and support for yesterdays engine in 10 or 20 years? Not even close."

When you post these very questions to Thielert and Austro--and we do--it's not surprising to learn that they aren't surprised to hear it. You shouldn't be surprised to learn buyers of $700,000 airplanes also ask it.

Both companies negotiated long-term supply arrangements. Austro is working through Daimler-Benz's MBTech with what appear to be very long-term agreements. These companies have thought through these product intros because for Austro alone, they've got $60M on the line. They can also pick up manufacturing themselves, but they lose two big advantages: scale and the automotive supply chain quality. If you watch the video, you'll learn that vendors already supply all of the engine's accessories.

This is really no different than buying an airplane from a startup company than could go belly-up in two years.

To me, the larger issue remains can an engine designed for automotive applications where it runs at 15 percent power most of the time be adapted to survive long term at 80 percent? That has yet to be proven, as has the entire diesel idea for airplanes.

They have definitely demonstrated merit. They have not demonstrated market legs.

By the way, what Austro has done would probably never happen in the U.S. due to the tort environment.

Posted by: Paul Bertorelli | May 15, 2012 10:41 AM    Report this comment

"...the larger issue remains can an engine....[that] runs at 15 percent power most of the time be adapted to survive long term at 80 percent?"

This is indeed the larger issue. Three comments.

First, the only conventional gasoline engines designed to run at 80% power most of the time are automobile racing engines and they are typically replaced or overhauled after every race (if they make it to the end).

Secondly, boat engines are designed to run at 70-80% power all day and all night day after day against constant heavy drag and no coasting. Only diesels can survive such constant stress.

Thirdly, engines driving oil well pumps can carry on for 20 years, day in and day out, and these are always diesel. As long as these engines are kept well-lubricated, they are quite happy to keep going forever.

Posted by: nicholas budd | May 15, 2012 11:01 AM    Report this comment

Paul and Kent,
Apparently my 747 analogy was not enough. I guess my statement just doesnt work well. I hope you can see my point though. In the US, you can use time saved to justify the cost for piston business travel, or even recreational travel. Most people don't count the total cost of plane ownership and training flights though. At some point you are taking the fine piece of engineering transportation and manufacturing art because you WANT to. IOW, your plane has become a flying Ferrari. You fly to fly even when you need to get some where.

When you get to that point less and less people become pilots. What percentage of Europeans own planes? When you get there what happens to the US market and even world market? You go from millionaires to multi millionaires as your likely owners. It spins faster and faster until you get zero love for GA in the US where the lines are in different places.

Sure, you still have tiny fun planes, but they will be sixth class users of the airspace.

Posted by: Eric Warren | May 15, 2012 11:02 AM    Report this comment

Paul, good comments, but on this statement

"To me, the larger issue remains can an engine designed for automotive applications where it runs at 15 percent power most of the time be adapted to survive long term at 80 percent? That has yet to be proven, as has the entire diesel idea for airplanes."

Companies that make VW boxer motor conversions (AeroVee, Limbach, Sauer, etc.) would claim that it is possible to make a good, reliable aircraft engine from an auto engine. The VW air-cooled boxer is no mainstream engine today, of course.

Posted by: Kent Misegades | May 15, 2012 11:09 AM    Report this comment

Eric, most pilots of 747s learned to fly in a Cub or C150. Wipe out the low end, the 'toy planes', and where do we get tomorrow's commercial pilots? The military, which will likely have more unmanned aircraft than manned aircraft in a few years, is not going to be able to provide the commercial pilots as they have in the past.

Posted by: Kent Misegades | May 15, 2012 11:13 AM    Report this comment

First, engines actually stay around for a long time these days. You can get crate engines for lots of old cars you would never expect to. Also, a lot of the changes in car engines are minor stuff that gets stripped.

Still, if you have the volume, you simply certify the newer better engine and replace rather than rebuild. If the cost is slightly more, but has benefits, then you are no worse off. Not the best example, but A DA 42 could potentially have gone from the original Thielert, to the second one, to the Austro. (IIRC).

Drones may actually help us here.

Posted by: Eric Warren | May 15, 2012 11:13 AM    Report this comment

Most, if not all of the "fuel savings" of the aviation diesel engines come by virtue of 21st century computerized engine controls. If the same technology is applied to AVGAS engines, we would likely see greatly improved fuel economy.

The "high durability" of diesels in terrestrial applications comes by virtue of the overbuilding of the engines (read HEAVY) necessary to tame the diesel's power pulses. Lightening the engines as necessary for aviation will increase complexity (cost) and reduce longevity (safety).

Put common rail direct injection with 4 valves per cylinder and computerized engine controls on an ignition engine running on 91UL and you'll get all the reliability, fuel economy and horsepower we could ever need (up to 350) on an engine that costs less than diesel ever will. For 350+ HP, turbine is the clear choice.

Spark ignition engines are ideally suited for aviation use and the ONLY reason to even consider diesel is caused by politics, not their technical superiority. This is because of the "one-fuel" myth. 100LL was never a truly viable "one-fuel" solution when it was introduced. "100UL" isn't either. JET-A as a piston fuel is a non-starter for engines 200-350HP.

Why don't we have unleaded AVGAS with TEL added at the pump AS NEEDED? The "need" will gradually decrease as engines like the TEO-540 become available and the "problem" slowly goes away as the cost of the TEL additive goes up. It's a simple solution that is technologically possible TODAY.

Posted by: KRIS LARSON | May 15, 2012 11:15 AM    Report this comment

Eric: "What percentage of Europeans own planes?" According to data from GAMA and AOPA, here are the stats on the number of pilots per million citizens for a few countries:
USA 2,019
Canada 1,789
Germany 1,012
France 653
Luxembourg 1,594
Switzerland 1,645
Sweden 1,034

I'd bet if you compared states in the U.S. with weather similar to Europe, you'd find the # pilots / million very similar to the US.

Posted by: Kent Misegades | May 15, 2012 11:17 AM    Report this comment

If any of the diesel alternative engines ever get past the development stage we may find the real answer is not a debate between a between a slow turning, large displacement gas engine vs a higher RPM, gear reduced diesel adapted from the automotive world. Some, like the DeltaHawk, seem to be perpetually just around the corner for certification, while others are game changing designs if they can get out of the lab. I have high hopes that the Nutating Disk engine will be the answer, turbine like characteristics (size, power-to-weight ratio, low vibration, Jet-A fuel) with piston power type production costs. Fortunately, the military UAV market is pushing several of these technologies through the development stage and hopefully to production. Like the civilian market, the military market needs a cheap (relative to a turbine) heavy fuel engine class optimized for 100 to 300 hp operation.

Posted by: John Salak | May 15, 2012 11:26 AM    Report this comment

I guess I don't see the point to the extent that you would seek to call Europe a joke. It is anything but. Yes, it has some ridiculous regulations, high fuel costs and taxes. But people still fly and we see innovative products coming from Europe.

I saw a bunch of Cirri, Cessnas and Mooneys flying in Friedrichshafen. You have to be somewhat wealthy in this country to own a new airplane and probably wealthier still in Europe. This trend has been well established since the 1980s.

Posted by: Paul Bertorelli | May 15, 2012 11:26 AM    Report this comment

Like I said, even a 747 can be a toy. Please try to get my point. I need your help as I am not a great communicator.
Training could go like it did in Europe. It gets very expensive and gets done by in house or contracted schools. Don't forget a lot of them one here still. My plane was used to train BA pilots here in the US before I bought it.
I think the euro ownership rate is much smaller than here. They have great clubs, because they have to. When you half or quarter the planes in the US, what happens to the number of airports? Schools? Services on airports? As it spirals down it won't stop neatly it will crash through the new equilibrium. Another decade of virtually no manufacturing like the late eighties to nineties. Great! Just great.

How about we avoid becoming them? And what happens to them when we become them? Just like they get over on our big military presence, their costs for aviation will increase if we decline. Eventually, even chicken little isn't guilty of hyperbole.

Posted by: Eric Warren | May 15, 2012 11:38 AM    Report this comment

It's a relative joke. I am guilty of hyperbole here because I am really passionate about what will happen if some trends continue or get exacerbated by bad decisions.

We can't have a fuel solution that destroys a big chunk of the fleet. We can't accept user fees. We can't even accept that the 172 is a perfectly good plane for schools. (that's also hyperbole, and food for another thread).

We must stop thinking that a marginal safety improvement in training will solve our issues. We have to stop whining about dollar costs while the other side of the value equation is what's really killing us.

We have to get tough on the people who are eating our industry, even if we have to go a bit over the line. The scammers, junk yard keepers, form over function CYA types, and the unable to change types need to be pushed into closets and neither be seen nor heard.

Drastic isn't something that aviators are comfortable with, but we have to separate drastic in the sky from drastic business changes.

Posted by: Eric Warren | May 15, 2012 11:55 AM    Report this comment

Kent, you're right about the VW and Suburu engines and so forth. But what these don't have is the large populations of high-time engines over many years like, say, the O-200 or O-320s.

I see the auto-converted diesels in the same space. So far so good, but no years of experience to prove their durability and economics. They may very well get there, but they haven't yet.

The point about boats and pump engines is good. It's my impression, however, that weight is a concern in the kind of cars the OM640 is installed in, so like an aircraft engine, I suspect its structure is shaved down as a compromise between durability and weight. If so, does the aircraft duty cycle impose loads outside its high durability limits? We don't really know that. We'll find out.

As for the direct injection and the claims of efficiency for gasoline engine...well, bravo. So why don't you see these? You did. That's where Rotax was going with its V6 line, since withdrawn. Why? Lots of reasons, but one is market size and the enormous amount of money necessary to develop a new engine that won't sell many units.

I'll remind you that both Toyota and Honda dabbled here, too. Toyota's FV4000 was a 360-hp watercooled powerplant complete with fuel injection and full-authority digital engine controls. Sunk without a trace. See above. Perhaps it will re-emerge.

Posted by: Paul Bertorelli | May 15, 2012 11:58 AM    Report this comment

So it's easy for armchair engineers such as myself (and you Kris, except I think you're a real engineer) to say efficient gasoline is so obviously the way to go, but a quite another to get a project going and get dope slapped by reality.

And that's why you see these diesels from four companies, but no gasoline engines of the sort you imagine are the obvious answer. The diesel technology is here now. It works now. Gasoline efforts had tried and failed. But someone may try again and succeed. The technology is certainly there. Diesel could fizzle.

Or maybe the coming wave of electric airplanes will render this discussion moot. And perhaps I'll be elevated to Pope.

Posted by: Paul Bertorelli | May 15, 2012 11:58 AM    Report this comment

Eric, it is hard to compare Europe and the US as aviation developed differently there and here. While the US was excited about daredevil flying and barnstorming, Europeans preferred to establish flying clubs. Americans being the individuals we are prefer to own their own planes. But many of these now stay in their hangars, my A&P son tells me the number of hours on planes he's seeing for annuals is down to 25/year. Maybe we need to look at how Europeans have made flying affordable through clubs. The EAA chapters should be the ideal means for this, but EAA headquarters frowns on chapter ownership of aircraft for liability reasons. I have the impression too that Europeans pursuing flying as a career prefer ab initio schools; Lufthansa's program, much of it in Phoenix, is excellent and includes financing of much of the cost. While it pains me to say it, in ten years I'd bet that the majority of our old spam cans will be scrapped for lack of people who can afford the maintenance and fuel costs.

Posted by: Kent Misegades | May 15, 2012 12:03 PM    Report this comment

By the time they're through squabbling, vapor-waring and willy waving, it will be all over for the ICE anyway. In 20 years time, no new cars will be sold with ICE - it will all be electric. Aviation is going to take slightly longer, but not much. The electric motor is perfect for aviation.

Posted by: Adam Frisch | May 15, 2012 4:17 PM    Report this comment

I think it interesting how aviators become infatuated by the thought of applying ‘advanced automotive technology’ to our 100LL burning ‘dinosaurs’.

Also, the lure of using diesel fuel instead of avgas.

I look at this from a different perspective. I fly with two TIO-520s. When I spool them up for take-off, I (and the plane’s manufacturer) expect 335 Hp per side. I get that with 100LL. Could I get that with diesel? Possibly, but I’d have to burn more of it to make the same power. Avgas is simply more ‘energy dense’ (for want of a better term). Could a diesel be made to provide 335 Hp using less fuel than I burn using avgas? Maybe, but I only use this power setting for 3-4 minutes max. I know I’m burning more avgas than needed to make the Hp, for cooling purposes. Would it be worth the complexity of adding an electronic control system for the fuel injection, four valves per cylinder or variable valve timing to get better efficiency? Not in my opinion.


Posted by: Edd Weninger | May 15, 2012 4:46 PM    Report this comment

When I’m somewhat pointed in the right direction, I bring the power back to about 75% for cruise-climb. Say 250 Hp per side. Just like the TO settings, it takes a certain amount of avgas to make this power. It would take more diesel fuel to make the equivalent power. To do this, I adjust the MP, RPM and mixture settings. Do I need a complex electronic system to do this? Not in my opinion, the task is not difficult with Gamijectors and a JPI readout. Would there be a benefit from burning diesel? No. I’d need to burn more of it to get the Hp needed for the climb.

OK, I’ve reached my assigned altitude. Depending on my whim, I can use a number of power settings to get to where I want to be. This is where avgas/diesel is more of a factor. This phase of the flight may be 2-4 hours. Here, a theoretical, more efficient engine burning diesel might have a slight advantage making the Hp I want for my cruise speed. I will, however, have to carry more of it to get the range needed. If an extra fuel stop is needed, that blows up any small, improved engine efficiencies.

Unless there is a quantum leap in battery technology (nothing on the 10-year horizon in spite of aggressive development investments) electric motors will not be practical for aircraft.

Posted by: Edd Weninger | May 15, 2012 4:48 PM    Report this comment

I have ranted long enough but you seem to be dancing around what I am trying to convey. The economy we have in US aviation is on a slope where every marginal loss of activity creates more losses. If you add an individual owner, that's as good as adding like 3 or 4 club members economically. People yell fuel cost, but you can only reduce fuel cost by adding hours flown. To do that, you add value to the hours flown. Prime way to do that is to do things that will add more pilots. Prime way to destroy it all is to allow a bunch of planes to get grounded due to lack of fuel/engine choices.

Accepting a euro style community doesn't mean you get one. What you would get here is such a retrenchment that it would be even smaller, AND it would likely spill over into boating and golf and skiing as more people learn to avoid capital investments into entertainment. Lock up your daughters and buy an armored SUV because drinking and letchery will be the beneficiaries. (yes, more hypbole). Also, it would affect the europeans as less volume means even higher prices for them.

Posted by: Eric Warren | May 15, 2012 5:12 PM    Report this comment

So back to my main point, and I will try to shut up :)

There must be a fuel solution for high performance planes and likely their can only be one fuel being sold besides Jet A. We can all replace engines, but if any owners group loses much performance they will make such a stink it will kill everyone's sales.

So, any solution that over weights or overly slows the Corvalis/Cirrus/bonanza/2o6/mooney/mirage won't work for GA. you can tell those solution people to give up. Too many FBOs will only accept one piston fuel, period.

Optionally, any planes that can accept a jet A burning engine, or that sip auto fuel that can be canned in, can be retrofitted. So, if you can develop turbines for everything over 250 hp, and diesels below that, then great. Or auto gas under 200 and diesel burning Jet A above that, okay. But if you have a solution that fails above 225 hp, and no idea what those owners will do, then you better figure that out because what you don't have is a solution at all. You have a new product which will rather quickly kill demand for itself as it kills GA.

I hope I am clear on that. That's the constraints and the outcomes as I see them. New facts can always change things, but I am a good predicter of stuff like this.

Posted by: Eric Warren | May 15, 2012 5:13 PM    Report this comment

By the time they're through squabbling, vapor-waring and willy waving, it will be all over for the ICE anyway. In 20 years time, no new cars will be sold with ICE - it will all be electric. Aviation is going to take slightly longer, but not much. The electric motor is perfect for aviation.

Posted by: Adam Frisch | May 15, 2012 5:17 PM    Report this comment

Edd: "Avgas is simply more ‘energy dense’ (for want of a better term)." Really? As far as I know, diesel has a higher energy density (36.4 MJ/l) than gasoline (34 MJ/l).

Adam - It is hard to see electrics replacing ICE, but who knows? One ought to call electrics though 'coal-powered' since we'll be needing batteries charged from a powerplant in most cases. Plus, oil is poised to plummet in cost as fracking is employed everywhere to tap into our huge shale oil reserves.

Posted by: Kent Misegades | May 15, 2012 6:10 PM    Report this comment

The claim the ICE will be gone in 20 years is absurd. First and foremost, electrical power lacks transportability, and even with the wild dream that battery technology will take several quantum leaps, where does the electricity come from? In the US, COAL with it's attendant costs. I own a hybrid car, but the foundation is an gas powered engine. I would suggest perhaps we'll see natural gas powered vehicles, but not electricity. Aldous Huxley's Brave New World may contain battery pack vehicles, but not the great expanse of the majority of our US.

As to electric motors for aviation, they may work, but the extension cords will be a fascinating challange. . .

Posted by: Burns Moore | May 15, 2012 6:26 PM    Report this comment

"...Edd: "Avgas is simply more ‘energy dense’ (for want of a better term)." Really? As far as I know, diesel has a higher energy density (36.4 MJ/l) than gasoline (34 MJ/l)...."

I'm looking at it from a weight perspective. I think diesel weighs about 7.2 lbs/gal and avgas about 6.1 lbs/gal.

I've already started my Maker's Mark for the evening so I'll have to wait 'til tomorrow to figure out how much my 163 gallon capacity will provide. I'm guessing avgas will have an advantage.

Posted by: Edd Weninger | May 15, 2012 6:33 PM    Report this comment

"In 20 years time, no new cars will be sold with ICE "

Saying this twice doesn't make it any less preposterous. Do a little Web surfing and you'll find that the rosiest most enthusiastic forecasts have electric vehicle penetration at around 25 percent by 2030. Current market penetration of hybrids--not pure electrics-- is under 3 percent and has recently fallen.

The electric car forecasts ignore one important factor: Gasoline and diesel technology is not standing still. It continues to make gains in performance and economy. Car guys barely understand what excites buyers and I suspect electric car makers likely know even less. Also, they ignore another important fact: the unpredictable nature of how technology impact sfossil fuel production and thus prices. That's why the peak oilers have always been wrong.

As for airplanes, electric is a great option for a niche, such as sport flying and motor gliders. Ten years from now, you will not see an electric airplane that can do what a Cirrus SR22 can do.

Twenty years? Maybe. Someone has to invent battery technology with density capable of five hours of endurance at 200 MPH. Not seeing that on the horizon.

The major game changer could be climate regulations. But it won't be market forces, I don't think.

Posted by: Paul Bertorelli | May 15, 2012 6:34 PM    Report this comment

"Gasoline and diesel technology is not standing still."

Well put! I was involved in Bosch's development of diesel injectors and direct gasoline injectors, twenty years ago. That technology took a decade to find its way intro production, can you imagine where we'll be in another decade. 84 MPG in a stock VW Passat TDI - not a bubble car - is pretty amazing, even if the Australian couple who just achieved this did some unusual driving. With figures like this, who needs a hybrid? Climate regulations? Does anyone really believe that stuff any more?

Posted by: Kent Misegades | May 15, 2012 6:50 PM    Report this comment

I think a large part of our lack of consensus arises from a disagreement over intended use:

1: After 40 years in aviation, USMC and airline, I NEVER considered owning an airplane until I needed to cover great distances in a relatively short time frame

2. Most people that I know/correspond with that own high performance aircraft have them for the same reason I do; they have a requirement to TRAVEL

3. European derived aircraft WILL NOT fulfill that requirement

4. The distance from Paris to Tel Aviv is less than St. Louis to Los Angeles. Those of us that own hi perf traveling machines, T210, Bonanza, Saratoga, Cirrus etc own them to travel not obtain $100 hamburgers.

Long term viability of GA is an important factor and may well depend on cheaper entry to aviation, but for those that really sustain the industry not "rocking the boat" is equally important.

Anything that detracts from the continued involvement/growth of the upper end of GA will greatly detract from the long term survival.

Posted by: Burns Moore | May 15, 2012 9:21 PM    Report this comment

Adam - As I said before in the previous related blog, it would take a 20x gain in battery capacity to even begin to make battery based electric power practicle in light GA. Not happening in 20 years. Maybe in 200 years. Maybe. And assumes that the ecomonics of batteries don't consign the technology to the scrap heap, at least as a mass transportation energy source. Which it will.

Edd - Check your calculations. SFC has units of lbs/hp-hr. Typical gas engines have SFC's on the order 0.4-0.6. Diesels are 0.3-0.4. I work for a company that makes diesel engines for large trucks. They're seeing SFC's in the low .3's even with all the required emissions mitigation equipment. Without all that crap they'd be doing even better. And aviation engines don't (yet) require any of those emissions controls.

Anyway, if you notice with those units, it's mass, not volume based. Two engines, one gas, one diesel, making the same power, even if the SFC were kept constant, would have the diesel burning LESS gallons per hour due to the higher density of diesel compared to gas. And with the lower SFC that's typical of diesels the GPH would go down even more.

Posted by: Andrew Upson | May 16, 2012 1:28 AM    Report this comment

Coming in late on the reliability of diesels running at 80% power over long periods, question, the answer is, they do it all the time in agricultural tractors (and a lot of the time in trucks on a freeway).
Before I get shot down, consider the similarities between truck/tractor engines and auto diesel engines.
The first auto diesel car engines, (Mercedes and Peugeot) were lightweight designs of van and truck engines.
Then Fiat invented the common-rail injection system in its cars (with a leap forward in fuel efficiency of at least 10%), which quickly migrated back to the commercial sector.
Common rail made electronic control of injection much easier (while increasing maintenance costs) and it is these units now being used by Diamond et al.
Electronic injection lets engines be "mapped" for different usages, so now the essential difference between the engine of they Mercedes on the autobahn and the Mercedes van trailing behind is the electronics, one mimics gas cars the other tractors...

Posted by: Brian McCulloch | May 16, 2012 4:38 AM    Report this comment

Gee Paul , I've only been saying what you've just said for about the last seven years ! Nice of you to finally see it :)

Posted by: RANDOLPH PALMA | May 16, 2012 5:21 AM    Report this comment

Brian, you may be right on the diesel durability. Austro says that Daimler's computer modeling predicts unencumbered durability at high power and high hours. Of course, computer models are one thing, real service another. At some point, the engine operating history reaches a tipping point of demonstrated durability and the numbers suddenly turn the corner. We'll know in five years, I guess, when they reach a million hours.

Edd, Andrew gave you numbers on SFCs that flesh out why diesels with incrementally better fuel economy outperform gasoline engines in range and endurance. One simple example is something like a DA40 or any single engine. Let's put 40 gallons in it. For avgas, that's 240 pounds, for Jet A 280. Using typical gas and diesel SFCs, avgas dry tanks range is 658 miles. The Jet A is 830 miles. Down fuel it to equivalent range and the Jet A airplane carries about 9 less gallons of fuel to go as far.

But...it goes a little slower and its less fuel required doesn't quite offset the heavier engine. Diamond addressed this in their twins by reducing the empty weight and raising the max certified weight. Still, the Austros are 120 pounds or so heavier than the Thielert's and heavier than a Lycoming O-360.

These are tradeoffs, obviously, and they are incremental, not orders or magnitude.

Posted by: Paul Bertorelli | May 16, 2012 6:11 AM    Report this comment

"3. European derived aircraft WILL NOT fulfill that requirement"

Burns, in that case, I'd ask why you think Diamond's 190-knot DA42 is not a traveling machine? Or Pipistrel's recently announced four-place 200-knot Panthera? Or, for that matter, the TBM850. Or the Tecnam P2012 or the Flight Designs C4.

These are all European designs. I don't get this apparent prejudice against European designs. It's important to understand that any airplane manufacturer today is not building with local or regional markets in mind, but a world market. Something like 40 percent of Cirrus sales are offshore and I think the number has been as high as 60 percent. Similar for Diamond.

Posted by: Paul Bertorelli | May 16, 2012 6:28 AM    Report this comment

"any airplane manufacturer today is not building with local or regional markets in mind, but a world market."

Bingo - and once outside the US, Europe and a few other places, there is no avgas, but plenty of Jet-A. If you want to sell aircraft into China, South America, Pacific Rim, India, etc. you had better be able to burn mogas or Jet-A.

Posted by: Kent Misegades | May 16, 2012 7:13 AM    Report this comment

"But...it goes a little slower ..."

Really? Everything I've seen is that for the same hp the diesel goes a touch faster. The higher torque of the diesel allows for a steeper pitch on the prop for the same rpm which translates into more thrust. All else being equal anyway.

Granted, all else is very seldom equal.

Posted by: Andrew Upson | May 16, 2012 9:32 AM    Report this comment

Not really, Andrew. The best direct comparison is the gasoline powered versus the diesel-powered DA42. The Lycoming version--180 HP per side--cruised at about 155 to 160 knots, while the diesel version--135 HP--did about 150 to 155, typically. There was a similar speed Delta between the Cherokee version and the DA40 versions. Don't have the data in front of me, but the gasoline version was faster and had better runway performance.

Having said this, the new V1 version of the DA42 has a lot less cooling and airframe drag so it has gained a good 15 knots. But if you stuck the gasoline engines in the same airframe, what would you see? I don't know.

Lets not forget the weight. The Lycoming are 50 pounds lighter than the Thielerts, and 170 pounds ligther than the Austros. In a light airframe, those are significant numbers.

Posted by: Paul Bertorelli | May 16, 2012 9:56 AM    Report this comment

I never saw any anti euro bias selling Diamonds, and I haven't flown a Pipistrel but i am already a fan. There is an anti new design/engine bias and an "it ain't Cessna/Beech" bias, and an anti "plastic" bias. I have also noted before that bonus depreciation is bad for the business, but I still say that GA's only political protection from those who would destroy it for tiny self interests are the manufacturing jobs. We need domestic production.

Lastly, I live in Houston, and know lots of oil and gas people. If an oil company opened a bank, they would have my business tomorrow. They work harder for less margin than anyone else. They all say there is plenty of oil for this century. They can tell you where enough is, and where their is likely more if they were allowed to even look. I gather the real problem with Chinese demand is that it could crash causing a whiplash where oil drops to 25 which then leads to it rising too high years later.

Posted by: Eric Warren | May 16, 2012 10:20 AM    Report this comment

What are the power setting between the Lyc and Austro powered DA-42's when you saw those cruise speeds? Were they both at 75%? That would be a lot less hp in the diesel for only a 5kt loss in speed. I'd be interested to see the speed comparison when they're both set for, say 100hp per side (~75% in the diesel, 55% in the Lyc).

As far as weight, yes that is a big issue. Assuming Deltahawk is being truthful (always dangerous with products not yet being delivered) their V-4 diesel weighs very close to an IO-360. Installed weight is only 20lbs or so more (dry weight is nearly identical). For a longer flight the fuel effeciency advantages of the diesel make the total mission weight (installed engine plus fuel) about the same for a 2 hour flight. After that mission weight favors the diesel.

Theilerts will take more to offset that weight penalty. The Austros won't see a weight advantage in any normal GA use.

So for a $100 burger run it'll be hard to beat the light weight of the gas engine. But if long distances are more typical one can see a weight advantage from diesel.

Posted by: Andrew Upson | May 16, 2012 11:12 AM    Report this comment

I can't recall exactly, but I would normally have taken the data at 70 percent for the Lycomings and 80 percent for the diesels, for that's how they are operated in the real world.

The 100-HP cross comparison isn't all that illuminating because you can't mask out the installation differences. It looks like the diesel had a lot more cooling drag than the Lyc, given what Diamond did with the V1. So our take has always been to compare performance as a system--airplane and engine together. (Plus the money to make both of them go.)

Posted by: Paul Bertorelli | May 16, 2012 11:46 AM    Report this comment

In assessing relative cross-country performance between the Austro/Thielert and Lycoming IO-360, there is another factor, which is that the diesel is turbocharged and the IO-360 is not. Above FL80 the Lycoming performance falls off and the diesel is happy up to FL160. There is not much of a speed delta in cruise settings (70-75%) but there is a large difference in fuel consumption (5 gph for the diesel and 7 for the Lyc, running LOP w/Gamis.

Posted by: nicholas budd | May 16, 2012 12:00 PM    Report this comment

Last I heard the 360s were pretty likely to not run LoP even with GAMIs. IIRC GAMI warned the installation may not succeed in allowing LoP on those engines. Am I mistaken?

Posted by: Eric Warren | May 16, 2012 12:04 PM    Report this comment

So that's 126hp for the Lyc, and 108hp for the Austro. Still only a 5kt loss in speed for 36hp total (18hp per side) reduction in power. Not that bad when you think about it.

Just trying to understand the performance differences. And it doesn't seem like the arguement that diesels are slower is really accurate or meaningful. To me anyway. I would expect an airplane making 86% of the power to be slower. That's not an arguement against diesels. It's an arguement against lower power engines.

Bolt a 160 or 180hp diesel onto the DA-42 instead and I'll bet that the takeoff performance and cruise speed performance gaps relative to the O-360 versions would come down substantially, and might even favor the diesel in some regimes, depending on the weight of the theoretical 160-180hp diesel.

Posted by: Andrew Upson | May 16, 2012 12:31 PM    Report this comment

I have a VW TDI, I average 41mpg on my commute to work which is ~25 miles each way. The car has 130hp and 249ft-lb torque. I wish Ford sold their focus and ranger TD's in the states.

Your points are good, I think Turbo Diesel technology has a huge potential now that the euro car companies are investing more and more money on building high endurance, high efficient, clean diesels. There are some manufacturers that are using overlapping cycles so the torque pulses are reduced to close to a low RPM gas engine is. To top it off some diesels are better suited at 3k RPM than they are at 5k rpm.

The weight will be a problem especially if you try to run the scrubbers on the exhaust. The new 1.8 TDI in VW has been pushed up to a higher RPM.

This is where I'm going to get away from the norm. A diesel-electric would be perfect. Build a light diesel generator and have it feed a capacitor bank that runs an electric prop motor. Heavy yes, but the hybrid diesel cars that have been prototyped gets upward of 160mpg. Gets rid of the gearbox, solves the torque pulse issue. Small Diesel generators that run 100% duty cycle already exist with thousands of hours on them. Electric drive components are extremely reliable, the capacitor bank could be designed with a 20min run time for emergencies.

The other issue is Jet-A weighs more than Gas. Do bad no-one has tried a LPG engine.

Posted by: Joseph Chambers | May 16, 2012 12:40 PM    Report this comment

Most people are rather clueless about electric motors. First of all, an electric motor has 90% efficiency compared to a ICE's 25%. That means that any battery capacity/energy use doesn't have to match the energy density of fuel - it only needs to achieve a quarter of it. And frankly, that's not very far off. Battery capacity doubles about every 7 years. It's performance doesn't degrade with altitude and and has limitless TBO. It has a power to weight ratio higher than any other prime mover. Think jets have good P-to-W ratio? Not compared to electric motors.

The coal argument is also moot - it is much more economical and friendly to produce all the power in one spot and then distribute it via an already in existence infrastructure - power lines. Shipping crude oil half way across the world, trucking it to and from a refinery and then inefficiently burning it in your ICE (that hasn't developed at all since the 30's) is not.

I'm not on the side of electrics because I'm some environmental nut - I'm on its side because it makes so much sense. Especially for aviation w high altitudes and reliability. Power storage needs still to be solved, but they will get solved.

Posted by: Adam Frisch | May 16, 2012 12:42 PM    Report this comment

But what is the weight of the equivalent HP engine?

Diamond has figured out a pretty decent trade off. As a rule of thumb you are best off with a slightly lower HP diesel than equal. You get similar performance overall due near equivalent thrust. Top speed is lower, but economy is much better. Thrust is nearly equivalent.

Plenty of plane makers made the same trade when offering turbos in the 60-s to 80-s. they put in a smaller displacement but boosted engine.

Later planes were designed with turbo in mind to start it seems, and they went with same engine, bolt on turbo.

Design a plane like the DA42 for diesel to start, and switching back to lycosaurs causes similar reverse choices to be made.

Posted by: Eric Warren | May 16, 2012 12:46 PM    Report this comment

BTW - Pipistrel won NASA's Green Challenge and flew 4 people, 200 miles on the equivalent of 1 gallon of gas in their electric plane. That's not only a higher gas mileage than has ever been achieved before in the air, but also on the ground!

This was achieved with todays full of limitations battery technology. Imagine what could be achieved when battery capacity increases?

Posted by: Adam Frisch | May 16, 2012 12:50 PM    Report this comment

Hello. how about a 350 hp aircraft diesel engine the same shape, size and weight as a TIO 540 or Continental 550?
it is running right now and meets all the weight size and shape requirements to fit in existing twins and heavy singles. to learn more about it go to www.EPS.aero
These guys have been quietly developing this engine in New Richmond Wisconsin and are now running the configuration engine on a test stand. it meet the weight, shape and size targets even in this early stage prototype to fit in place of a TIO 540 in a twin.
The reason you have not heard about it up to this time is these guys are the kind of engineers that do it first and brag later
like most disruptive technologies it is being developed by a small flexible group of brilliant engineers that also do not want to reinvent the wheel if it already exists. The engine is based on proven European Diesel combustion chamber technology similar to what Austro and Thielert are using but it is packaged in a very small compact configuration
they have extensive experience in engine manufacturing having been involved in bringing over 20 engines of various sorts into production. they have the unusual engineer characteristic of knowing they do not know everything and thus they utilized the best knowledge available in the world to help them.
They are finally coming out of the closet now. Paul I would suggest you should talk to them to see their engine run and see for yourself what they have accomplished.

Posted by: BILL LAWSON | May 16, 2012 3:14 PM    Report this comment

Adam - Did you even read the article I linked to in the last discussion along these lines? Here it is again in case you missed it (replace "slash" with "/" and "DOT" with ".").

http: slash slash www DOT altenergystocks DOT com/archives/2011/08/its_time_to_kill_the_electric_car_drive_a_stake_through_its_heart_and_burn_the_corpse_1.html

EVEN IF battery energy densities can get to the 4kWh necessary to make battery powered GA practical, producing that many batteries to allow most of GA to go all electric would make them so hideously expensive that turbines would be extremely attractive by comparison.

Besides, they (the USGS that is) recently announced the extent of the Green River Formation under Colorado, Wyoming, and Utah. 3 TRILLION barrels of oil, half of which is considered recoverable with current technology. That equals the rest of world's proven reserves combined. At current oil consumption rates that recoverable oil is equal to 210 YEARS of supply. Without a single alternative energy technology coming on line my great-great-grandchildren won't even have to worry about running out.

Posted by: Andrew Upson | May 16, 2012 4:47 PM    Report this comment

Sorry, that should be 4kWh/kg.

Posted by: Andrew Upson | May 16, 2012 4:52 PM    Report this comment

From Adam Frisch
"Most people are rather clueless about electric motors."

Nice ad hominem.

"First of all, an electric motor has 90% efficiency compared to a ICE's 25%. That means that any battery capacity/energy use doesn't have to match the energy density of fuel - it only needs to achieve a quarter of it."

When I quote SFC numbers you do realize that already takes into account to efficiencies of power source (whether batteries or liquid hydrocarbons), right? And, in fact, I'm being charitable by accounting for the 10% loss between the batteries and prop flange.

I'll grant you that electric motors are a lot more efficient at converting the energy from the batteries into prop rpm's than an ICE. But what you're forgetting (here I am being chartable again) it that's only a small part of the total equation. You still a source for that power, and liquid hydrocarbons are significantly less massive of a means to cart that energy around compared to batteries.

"And frankly, that's not very far off. Battery capacity doubles about every 7 years."


cont. below

Posted by: Andrew Upson | May 16, 2012 9:38 PM    Report this comment

"It's performance doesn't degrade with altitude and and has limitless TBO."

Uhhh, have you looked into temperature effects on battery charge? The motor doesn't suffer altitude losses, but the batteries sure do when they get cold.

"It has a power to weight ratio higher than any other prime mover. Think jets have good P-to-W ratio? Not compared to electric motors."

The electric motor itself? Yes, I will agree with that. But motor plus energy source is totally different matter. For just a 2 hour cruise duration, and using your claimed 400W-hr/kg battery (which I can't find outside of labs, but never mind that), and even giving 100% efficiency from battery to prop, and 100hp to the prop, you'd need 821lbs of batteries. Even if you claimed a 300lbs weight savings from the P/W ratio advantages, you'd still be 521lbs heavier than the gas engined plane. Even adding the 84lbs of gas in to give that same range for the power and you're still 437lbs heavier.

Electric, in this 100hp example, would only have a weight advantage for

Posted by: Andrew Upson | May 16, 2012 9:38 PM    Report this comment

"I'm being charitable by accounting for the 10% loss ..."

Proof reading fail. Should be "charitable by NOT accounting ..."

Posted by: Andrew Upson | May 16, 2012 9:42 PM    Report this comment

Andrew - I was not saying that we are there yet. I'm fully aware that power storage is the big hurdle and we have still ways to go. But it is progressing very fast, and now that Tesla Model S and many other serious electric cars are at the brink of wide acceptance, the development will speed up even more. I fully agree with Elon Musk - in 20 years time there will be more electric cars sold than ICE. But with all these hurdles, Pipistrel and many others still manage to make things that fly for 2 hrs. Isn't that amazing?

Cessna is developing an electric 172. Pipistrel their new Panthera. The Electra Flyer. Boeing their hybrid. Numerous smaller LSA-type electric things. It's happening. If I was a betting man, the last thing I'd be betting on today would be Lycosaurus engines or aviation diesels. They haven't managed in 50 years to improve or certify anything truly new, so I'd rather take my bets on electric. Good riddance.

Posted by: Adam Frisch | May 17, 2012 11:11 AM    Report this comment

Electric sounds good. Until you really dig into the details. And Elon Musk has a vested interest in pimping electric vehicles.

What's the useful load on the Pipestrel electric? What's the recharge time? What is the lifespan of the batteries, and how much does it cost to replace them?

What do all these electric goodies cost, after adding back in all the subsidies? You realize the Volt costs something like $250k to produce. There's $215k in subsidies necessary to bring it down to a price that very few are even willing to still pay. Last I heard (which was a few years ago) Toyota was losing money on the Prius.

Electric cars, outside of a few niches, are vanity products. Maybe, someday, the engineering and the economics will make them practical. But not in 20 years. In case you've forgotten, electrics have been around for a very long time too without much movement either. Diesels didn't go anywhere for a long time because of their weight penalty, plus avgas was cheap. Now avgas is cripplingly expensive and its worth the cost to develop diesels. And if Deltahawk is being truthful they have a 160-200hp diesel that's only 20lbs heavier installed than an IO-360. And it has the bonus of a turbo. Given some time Theilert and Austro will probably cut the weight of their lumps by quite a bit too. Though I won't push them until they actually do so.


Posted by: Andrew Upson | May 17, 2012 12:20 PM    Report this comment

I keep coming back though to money. Even if electric cars and airplanes were able to be made practical enough for wide market acceptance, the cost of producing the energy storage (i.e. batteries) would skyrocket beyond what even the moderately wealthy could hope to afford. There's just not enough production of industrial non-ferrous metals to support such a change. China, which has 95% of the world’s production of rare-earth metals, vital to batteries and motors, and a command economy, had to cancel a bunch of windmills because the cost of those metals had gone too high.

In order for electric power to go prime time they'll need to figure out a way to not use huge quantities of those metals, get recharge time down close to re-fueling time, and get the costs competitive without subsidies. That probably will mean some technology that replaces batteries entirely.

Posted by: Andrew Upson | May 17, 2012 12:21 PM    Report this comment

Kent introduced the concept of “lower end” hence it must be safe to assume that there is also a “higher end” and herein lays the problem. Example: an airport has a 4000 feet runway. The 150 driver who is looking for some weekend fun or preparing for an aviation career is “happily flying” out of the 4000 feet. However, “the higher end” wants an additional 2000 feet. Fortunately “free money “is available as a government grant---and everybody is happy as “nobody” has to pay for it as it is all charged to the "government pork ledger". Six months later the 150 driver suddenly experiences a 20% increase in hangar rent, a buck more for avgas, a 10% increase in hourly rate for mech/avionics services etc.--all because the Airport Administration has suddenly realized that the extra 2000 feet requires additional maintenance. Over time “resolutions” to issues as user’s fees, airport closings and many others have similar results—that is increased costs for the 150 driver with no associated benefits. I am certainly not advocating a halt in facility development—only a change in how the associated costs are being charged if we are serious about the future of the “lower end” which is indeed General Aviation. I realize of course that this is considered “heretic posturing ” – dividing the Aviation Community and claimed by certain “interest groups” to weaken our fight against whoever we are at the present fighting against—actually most of the times ourselves.

Posted by: HELGE SKREPPEN | May 17, 2012 1:48 PM    Report this comment

Your scenario sounds like someone in power decided to go after jet business. Fine, that comes from growth of the area. That growth can also lead to closing of the airport. If you eat at the government trough, you get what they throw in it. Cities rarely care about low end GA, and they especially like to get rid of pests. It's important for the piston pilots to be the best citizens, most active participants at many levels. There are no guarantees, but owners and businesses that are eyesores or otherwise undesirable can often get their whole segment in hot water.

Still, like neighborhoods that appreciate, you can find yourself priced out of a growing airport. That's life.

Posted by: Eric Warren | May 17, 2012 8:13 PM    Report this comment

There is a new 350 Hp diesel engine go to
to see it

Posted by: BILL LAWSON | May 19, 2012 8:47 AM    Report this comment

There is no www there William. Just eps dot aero

Posted by: Eric Warren | May 19, 2012 9:57 AM    Report this comment

Hint: Who cares about fuel costs? After buying, maintenance, annual, hanger, etc, etc, fuel differential between gas & diesel is irrelevant. Efficiency does not make a difference in the picture.

Posted by: Mark Fraser | May 19, 2012 7:59 PM    Report this comment

Thank you Eric for your executive level of recommendations -- obviously from inside your spiritual “Gated Community”--- for the lower end to be good and active citizens and stop whining and being rude---in other words behave as expected by lower end aviators with proper humility and respect for the upper end. I know our Tee shirts are sometimes faded and we have holes in our jeans – created by long time use and not fashion---but I certainly did not realize that our status was such that we were consider the “Pests” which must be eliminated---a kind of General Aviation ethnic cleaning I suppose. (Next time I participate in an Aviation Cookout I will make sure that there is no pesticide in the hot dog by having the upper end eat one first). I assume this is what you refer to as “that is life” or rather survival of the fittest—almost as an enhanced branch of Darwinism specifically adapted to General Aviation. (Paul; you should get a cartoonist on your staff—apparently he would have plenty of material)

Posted by: HELGE SKREPPEN | May 19, 2012 8:35 PM    Report this comment

Actually, Helge, I was talking about bad actors I have come across. There was a flight school that consistently had disassembled planes, parts, and refuse scattered across their area which was the first one next to the airport entrance. A similar scene at another airport by a shop that rebuilt turboprop aircraft that you would call "high end" but I knew were dangerous crap.

All piston aviation is low end. We pay our fair share only until a lot of kerosene burners show up spending money everyday like we spend every month. We then rely on the good graces of the owners of the airport, government or private, to not send us packing.

If you rent rather than own the real estate, this is all fair. I didn't like getting priced out of the only airport within 30 miles of my house, but you don't see a baseball sized chip on my shoulder. I've been priced out of my apartment before, yet I didn't scream classism or racism.

I am sure your situation is frustrating, but throwing a bunch of hate on people will only make things worse. No matter the neighborhood, there is a line that will cause the other neighbors to want rid of the pest. Let's not be the pests, and certainly not hateful pests.

Posted by: Eric Warren | May 19, 2012 9:24 PM    Report this comment

It used to be that those who expressed concern about cost sharing within General Aviation were classified as “divisive” which was not an honorable classification hence effectively shut down all further discussions. You Eric have indeed greatly improved on these “technics” by introducing “hate” and “frustration” as new causative agent for having the audacity to raise the issue of cost sharing. I am sure this “upgrading” will be greatly appreciated. We live in a society in which new technology is becoming more and more affordably to the average man. Technology associated with General Aviation is one of the few exceptions to this. There are several reasons for this but one is that different groups within General Aviation have different needs for services. However, the sharing of the costs for these services is not distributed proportionally to the actual needs and use. Some seem to claim that we have to increase the number of aviators which will bring costs down. For those who mean well— that is excluding those who make bucks on the present set up---this appears to be a miss application of “The chicken and egg philosophy”. If we do not get this right all the fun we have all had over the years will not be available to our grandchildren which is indeed a sad development.

Posted by: HELGE SKREPPEN | May 20, 2012 7:16 AM    Report this comment

I obviously said something that rubbed you the wrong way. This has gone a long way away from Paul's article so I will just say that I do believe we need to bring in more new pilots and aircraft buyers.

You seem to promote a close the gate philosophy yet want to preserve what we have for your grand kids. Don't improve the airport or we will have to pay more? Don't let new companies put the old ones out of business by offering better products and services? Let's divide things up based on need?

That's not a preservation policy, it's a recipe for certain death.

Posted by: Eric Warren | May 20, 2012 3:37 PM    Report this comment

Eric with your talent in “mentally editing and enhancing” reading material presented to you I suggest you run for office. With some counseling and polishing you would be a formidable contributor on The Hill . I agree, Paul is likely fed up with all this babble. Hence I am “shutting down the publishing office” for this time. But as “the saying goes” “I will be back”
Have a nice flight,
Stay away from ports with the long runways unless you want to pay a surge charge for avgas.

Posted by: HELGE SKREPPEN | May 20, 2012 9:21 PM    Report this comment

Eric with your talent in “mentally editing and enhancing” reading material presented to you I suggest you run for office. With some counseling and polishing you would be a formidable contributor on The Hill . I agree, Paul is likely fed up with all this babble. Hence I am “shutting down the publishing office” for this time. But as “the saying goes” “I will be back”
Have a nice flight,
Stay away from ports with the long runways unless you want to pay a surge charge for avgas.

Posted by: HELGE SKREPPEN | May 20, 2012 9:21 PM    Report this comment

Boy, you guys are so wedded to your old technolgy you can't see the forest.

Yesterday someone, somewhere tested a nano motor that ran on a millionth of a joule of electrical power. (Actually true) In five or ten year we'll be storing enough energy to fly from Panama to Gander in a full tank weighing about 3,12 KGM.

It nay not be a conventional electric motor, it may not be reciprocating or anything else we recognise but I can't see how anyone who lives in the computer age can possibly be having a debate that includes only current technology.

Wake up for heaven's sake. It may not be in 2012 but one day very soon all this will be utterly obsolete, and very suddenly.

Posted by: Chris Vernon-Jarvis | May 23, 2012 7:51 AM    Report this comment

Would you care to post some links to verify your claim that "In five or ten year we'll be storing enough energy to fly from Panama to Gander in a full tank weighing about 3,12 KGM."

My inherent skepticism made me think "perpetual motion machine" when I read that. But then I thought that perhaps that is unfair. I'm still skeptical, but am willing to investigate before passing judgement.

Posted by: Andrew Upson | May 23, 2012 4:04 PM    Report this comment

Heck, I'd be happy to have enough "nanos" to give me the equivalent of 670 Hp for take-off at 9,000' density altitude, lifting 350 Lbs of payload in addition to myself and 3 passengers and cover 500 NM with a reserve.

I'll need new engines in 5-10 years, so I'll be receptive. Keep us up to date...


Posted by: Edd Weninger | May 23, 2012 4:32 PM    Report this comment

Of course there's no source, it hasn't been invented yet, but for sure it will be.

Back in the sixties I worked in the spare parts department of an aviation manufacturer. I spent hours adding up the cost of lists of parts on customers orders. I did it until I got the same answer twice. Then I gave it to the guy behind me. If he got the same answer we sent it to the customer. All the clever punch card stuff was kept for the ordering and materials depatment.

Five years later, living in London, out of the blue one day my girl friend walked in and gave me a solid state calculator. It cost the equivalent of a decent TV today. If you had told me just a couple of years earlier would I have asked for your source? Don't be so silly! And for the last thirty years you have been able to buy an electronic calculator for about two or three bucks. I was in a Vietnamese market last week and was offered them for 70 cents ("You buy more? I give discount.")

One can not possibly live in the computer age and consider only the technology one sees in front of us now. If you need an aircraft 25th of May 2012, perhaps but in five, ten years?

Posted by: Chris Vernon-Jarvis | May 24, 2012 6:05 AM    Report this comment

"One can not possibly live in the computer age and consider only the technology one sees in front of us now."

That's true. But one can gain a reasonable understanding of the pace of progress and realize that Moore's law applies only to semi-conductors and microprocessors and is itself a unique exception in the annals of invention.

There is no Moore's law for battery capacity nor motor efficiency and technology. It is unlikely that 10 years from now--that'll be 2022--that what you're describing will exist, not because no one can imagine it now, but because the technology necessary to make it a reality isn't advancing fast enough.

Posted by: Paul Bertorelli | May 25, 2012 8:22 AM    Report this comment

Paul is right! What we sometimes fail to realize is that the basic technology we use for storing electricity in a battery—that is interaction between an electrolyte and metals—has been the same for literally several hundred years and there is no other system on the horizon. The improvements we have seen over the years are basically because of the selection of different metals—lead, zinc, nickel, cadmium and the latest “fad” being lithium. These metals have different fixed physical properties more or less favorable to the electrochemical process in a battery. Unfortunately we cannot change the physical properties of importance to battery operation any more than we can change the density of these metals. There might be some new metals with slightly more favorable properties on the horizon. However, this will hardly represent any major improvement comparing to the “leaps” we have seen in the development of computer technology.

Posted by: HELGE SKREPPEN | May 25, 2012 11:34 AM    Report this comment

I agree. for batteries or some other electrical energy storage device to store 10x or 100X what we can do now something unknown at this time will need to be discovered that allows this. unfortunately it is impossible to forecast this development until after it happens. this is a similar situation to what our view of the world was when we used vacuum tubes and we could not foresee what a semiconductor could do. or in the world of super conductivity where the accident of higher temperature super conductors was not predicted but when it was discovered it opened up a whole new possibility.

for storing electricity Super capacitors show promise but there are big obstacles there with the physics and materials as they are understood at this time. Hydrocarbons store a lot of energy per pound and for the foreseeable future they will be the practical source for aviation fuel even if they are made from renewables.

Posted by: BILL LAWSON | May 25, 2012 5:09 PM    Report this comment

Hi All, I'm new to this blog, but not the discussion around the future power for light GA Aircraft (

Posted by: Owen Wilson | June 7, 2012 7:21 PM    Report this comment

Part 2:
2. Modern (auto) Turbo Diesels produce as much power or more than modern high performance Gasoline engines, and the power (read torque) is delivered at RPMs better suited to swinging a Prop. (look at the last few years of Le Mans Racing results)
3. Fuel Economy is unsurpassed in modern diesel engines, and that also includes a number of Hybrid or electric cars too. (the winner of the economy challenge in New Zealand for the last few years has been a diesel, not a hybrid as you would expect).
Lastly.. the weight issue !! It is a problem because the high pressures required for compression ignition tend to spread an all alloy block thereby limiting their reliability and life, hence the reason why most Diesels have Steel liners, or even heavier Cast Iron Blocks. (part 3 follows...)

Posted by: Owen Wilson | June 7, 2012 7:27 PM    Report this comment

Honda engineers have come up with a unique solution in their 2.2L TD engine available in Europe in their Honda Accord from 2004 onwards. It is an all Alloy Block with Nikasil bores, but it has a CRFP Plug which surrounds the upper cylinders and contains the pressures of compression ignition, and results in an engine that is lighter than their own 3L V6 Gasoline engine (which is also very light) and produces more torque from 2200rpm up to 5000rpm (340Nm or 250 ftLbs)! This has got to be good for Aircraft applications, and now that Honda has got into the Aviation market with the Honda Jet, perhaps they could be convinced to provide these engines at reasonable cost to the GA Aircraft world. Incidently, when they were introduced in 2004, they took 8 records for speed and economy, achieving 84mpg (Imperial Gal) on a test run, and typically get around 50-60mpg in general use with a Manual GB.

Posted by: Owen Wilson | June 7, 2012 7:30 PM    Report this comment

For those who were so closed minded today's news brings a reminder that unexpected developments are, these days, always just around the corner.

"Paintable batteries." A five layer battery you can paint on any household surface with regular paint equipment.

Imagine that. Combine you battery with your regular paint coating. Essentially no battery weight because you had to paint anyway. I'm guessing that in the next couple of years that can be combined with a topcoat of paintable solar panel. An almost infinite power source for little or no weight penalty. Who'd want to cart around a heavy ICE and all that fuel?

Sure there are connection, vulnerability etc issues in aircraft but they will be solved and those upper wing surfaces were made for this.

Who'd a' thought it?

Posted by: Chris Vernon-Jarvis | July 2, 2012 2:23 PM    Report this comment

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