Piper's Archer DX Diesel

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Piper chose the Aero show two weeks ago to unveil itís new diesel-powered Archer DX for good reason. The work on the conversion was done at Continental/Technifyís skunk works at the Altenburg airport, a former East German military base where Thielert did all of the original test flying for its initial certification of the Centurion line. Further, as Piperís Simon Caldecott said in this video interview, Piper, rightly, sees the DX as more world airplane than a U.S. airplane.

After the close of Aero, I took a brief flight demo in the DX with Piperís Dave Athay to collect some performance data. As with all of the diesel conversions, the DX performed about as I expected or maybe a little better in cruise.

The DX has the 155-HP Centurion 2.0s; same basic engine as the 2.0, but with a tweaked ECU to deliver the higher power. For now, it has a 1200-hour TBR and a 600-hour gearbox replacement requirement. Although it concedes that the TBR needs to be raised, Continental insists the economics work at 1200 hours. More on that later.

According to the DXís draft POH and what performance observations I could make, the DX requires a little more runway for takeoffó918 feet (280 m) against about 800 (244 m) for the Lycoming-powered version. Thatís at gross weight, sea level on a standard day with 25-degrees flaps, which the DX POH recommends. The diesel climbs a little slower; the POH says 737 feet initial, compared to 775 for the gasoline version. But Iíd like to see a little more flight data on that.

But the comparison between the two is not straightforward and flightschools considering one will want to put a sharp pencil on their own numbers from a gasoline trainer against the diesel numbers. For example, although the DX initially climbs slower than the Lycoming Archer, it catches up at higher altitudes because the diesel is turbocharged. In time/fuel/distance to climb, the two are close. The DX gets to 8000 feet in 11.2 minutes and flies 16.3 miles on 1.8 gallons. The gasoline Archer gets there a half minute sooner at about the same downrange distance, but requires 2.2 gallons.

Cruise comparisons are muddier.†Do you compare them as equivalent horsepower? Percentage power? Or money burned? Using equivalent horsepower, the relevant metric is speed and fuel burn. Seventy percent power in the DX is 108 HP. But for the gasoline versionóremember, it has 180 HPó108 HP is 60 percent power. Comparing the two at those power settings, the DX will deliver 112 knots on 5.8 GPH, the gasoline Archer 114 knots on about 8.4 GPH. At higher power settings, the fuel consumption difference can be greater than 4 GPH. The higher you go, the more advantage the DX has, in speed, if not fuel burn delta, since the Lycoming necessarily burns less the higher it goes because itís making less power. I saw 126 knots TAS at about 80 percent power at 6000 feet, which was as high as we could get, due to cloud cover. That was on about 6.2 GPH. The Lycoming Archer POH says it will do that †speed at 85 percent power on 10.5 GPH.

I wonder if flightschools might change their training doctrine a little to accommodate the fact that diesels climb slower at pattern altitudes. I noticed this in the Redhawk conversion and itís true in the DX as well. If I were grinding out landings in the pattern, I might prefer the gasoline model or, in the diesel, simply not climb to 1000 AGL for the downwind. Thereís no particular need to do that. (In the Cub, Iím thrilled to make 400 feet.)

Proving once again that flying is hours of sheer terror interrupted by moments of profound stupidity, I found the means to test the carefully considered cert protocol for the Centurion. The Centurions use common-rail injection, returning fuel to the tanks from the pressure side. Dave Athay noted that the G1000 tracks tank temperature and sure enough, the left tank we were running on was warmer than the right. So Athay asked me to switch. Somehow, I managed to get the fuel switch to off briefly, before getting it on the right tank and feeding again. The engine sputtered and resumed running, just like a Lycoming would.

Well, not exactly. Two warning lights came on announcing both ECUs had failed. Obviously, they had not, otherwise weíd have been gliding. What we were seeing was evidence of the Centurionís automotive DNAóthe equivalent of a check-engine light. In the car, the ECU might very happily shut the engine down to protect the pumps and injectors from a low fuel-flow condition, but that logic would never get through aircraft engine certification. So the ECUs stay alive, but the fail lights serve as a fault indicator to check the high pressure pump and reset the codes, which the Tecnify techs did. (CORRECTION 4/30/14: The fault lights can be cleared inflight by holding down the FADEC button for three seconds.)

While the fuel valve is a little different than the gasoline Archer because the fuel system is also different, I donít think itís a bad design. My error was just due to simple carelessness, even if I caught it immediately. (The switch has an interlock pin to off; I donít recall pulling it, but I sure as hell must have.) Interestingly, the software has two layers of warning for low fuel. The first is a yellow low-tank warning light, the second a low rail-pressure warning light. Both of these assume a tank just running dry, not actually switching the fuel off, because no one would ever do that. The POH probably needs a limitation restricting journalists operating three video cameras and a notebook from touching the controls.

Besides paying closer attention to tank switching, this also serves as a reminder that diesel enginesóat least the Centurionódeliver impressive economy at the price of complexity, expense and if not the same robustness as a gasoline engine, a different kind of robustness. Thereís no free ride here. In any device run by software, there are always surprises, as Diamond found out when both Centurions on a DA42 quit because of an unforeseen power interruption to the ECUs caused by a flat main battery.

My initial analysis of the DXís operating costsóindependent of capital costs--show that itís not a player for the U.S. market in lower operating costs, which Piper concedes. But in Europe, where avgas costs $10 to $12 and Jet A is around $7, the DX looks attractive, even at a 1200-hour TBO. On paper, it appears capable of direct, engine-only operating costs of about $88 an hour, versus $112 for the gasoline Archer. At higher TBRs, the cost difference increases to nearly $50 an hour.

But here again, the Centurionís automotive DNA intercedes. Back in the beginning, Thielert struck a deal with regulators to enhance safety by replacing gearboxes at low hourly intervals. It made sense then. But 12 years later, the restriction lives on. On an hourly basis, the 600-hour, $6948 gearbox replacement package is, of itself, more expensive than the hourly cost of an entire Lycoming O-360 overhaul. I canít help but wonder if what was prudent conservatism in the beginning is now just regulatory inertia. Might those gearboxes really be good for twice as many hours or maybe even the life of the engine? If thatís true, the Centurionís economics appear incrementally better.†

Whether Continental got a good deal on its purchase of the former Thielert Aircraft Engine assets is, at this point, an unknown. It really depends on how rapidly they convince OEMs to adopt the Centurion line and how lively the conversion market becomes. Just as a datapoint, Thielert did about 270 conversions of Cessna 172s and Piper Warriors, plus some Robins, between the time the engine was available for STCs (about 2003) and 2008, when the company became insolvent. Call that about 50 aircraft a year, just to round it off. In some ways, the early STC work by Thielert was the smartest thing the company did.

During roughly the same period, but including the years after the bankruptcy, Diamond built about 600 DA42 twins and another 400 DA40 singles. Given current market conditions, thatís none too shabby. But the market has evolved since then, so demand is an unknown.

Of late, Piper has been on a tear with the Archer. It sold 48 Archer IIIs in 2013, making the PA-28-181 the hottest selling airframe in the Piper line, a position it hasnít occupied for years. Caldecott believes that rather than cannibalizing the Lycoming-variant, the diesel model will open new markets where Piper couldnít gain a foothold before. That will be Europe, Asia and probably Africa at some point, largely for a training market where avgas wonít be available, if it isnít already.

The airplane will live or die on operating costs; not payload, not performance and certainly not as a cheaper mousetrap, although Piper says the Archer DX, at $400,000, will sell for just under what the Cessna 172 SP does now. I havenít crunched the full number set yet, but the flight data I collected confirms that the airplane does burn about 3 to 4 GPH less than the gasoline version in typical operations or about a third less in block-to-block fuel burn.†

As with the DA42 and DA40, the real measure of the DX will be after a half dozen are out in the training world for a year. Weíll then see how robust the 2.0s is and how the long-term numbers play out. Piper has taken a measured risk on this project. Itís not a new cert project and I donít think it was a particularly expensive STC to develop. Itís nothing like the risk Diamond took with the DA42. Either way, risk doesnít define success; sales do. General aviation has been known to both reward and punish boldness.

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Comments (42)

The part of this article that jumped out at me was Quote PIper sold 48 Archers in 2013 Unquote. In 1979 Piper sold that many in 2 weeks. I am encouraged that PIper is at least trying to keep GA alive with some new products but these kind of incremental freshening of 60 year old designs is not going to turn the tide.

The only successful GA OEM is now Cirrus and they succeeded by innovation. Piper and especially Cessna, are the Buggy Whip makers of GA.........

Posted by: DAVID GAGLIARDI | April 24, 2014 11:22 PM    Report this comment

Smart; I'm not convinced. Creative/innovative? When Piper's"management" had a sure and proven winner with the Sport (LSA) Cruiser - just check the sales record under their brand - they dropped the line. Here was more then ample proof of the importance of "branding". Perhaps, my guess was like Cirrus also, NO vision that the biggest volume and untapped potential is filling the 2 place training market left by Cessna (150/152) which 31K+ were produced (1959-85), but more over, was the "breeding" ground (then upsell) for thousands of future pilots who ultimately became "aviation consumers";. DUH?

Posted by: Rod Beck | April 25, 2014 6:28 AM    Report this comment

Piper numbers plus the cost of $400,000 over 10 years at 5.5% interest for the DX compute to a rental or hire (commercial operations) break-even-point of 80 hours per month at $200/hr. Working with a 30% markup the hourly rate would amount to $260/hr plus CFI. I believe the flight school business is out of the Piper DX range because of cost and performance. Therefore, I predict that there is no future for the Piper DX Diesel as it is now.

Posted by: Rafael Sierra | April 25, 2014 7:39 AM    Report this comment

Paul: In calculating the economics of Centurion engines did you also include the cost of routine maintenance like oil changes? For most diesels, the good news is that service is required only every 100 hours instead of the 50 hour servicing needed for most avgas engines. But the servicing on a diesel requires much more expensive oil imported from Europe, hard-to-find filters, and the need to also service the gearbox -- either replacing, or removing and filtering the gearbox oil every 100 hours. On some diesels the gearbox filter and fuel filters must also be replaced every 100 hours. It adds up to being more than twice as expensive as the 50 hour oil change on a Lycosaurus.

Posted by: DAVE PASSMORE | April 25, 2014 7:58 AM    Report this comment

My question was partially answered by Dave above, but I'll ask it anyway to see if you (Paul) had any input from Continental on this. Do we have a good idea what these engines are like, from a maintenance perspective, operationally? We know the TBRs and gearbox replacements are annoying, but they are still, even for a very busy flight school, infrequent events. Flight schools will, though, be doing more routine maintenance on them. Replacing starter motors, oil/filter changes, maybe the odd cylinder replacement (or maybe not, with liquid cooled engines). The Lycoming/Continental avgas engines are pretty easy to get things on and off of. Are the diesels similar? If they have automotive heritage, my guess is no, at least not nearly to the same degree.

Posted by: Joshua Levinson | April 25, 2014 8:40 AM    Report this comment

I would love to understand how a single engine, fixed wing, decades old design airplane costs $400,000. Economy of scale I can somewhat appreciate. We can't quite compare airplane manufacturing to car manufacturing, yet when a high end luxury, new innovation type car like the Tesla only costs $80,000, (and I bet that thing has more gee wiz electronics in it then this Piper) and a diesel Piper costs 5 times as much (80,000*5=$400,000) something is getting added to the equation. I would think from a raw material standpoint the plane is even less cost, so it is labor, insurance, regulations? WHat are the soft costs that are killing this market.

I use to be an active PPL, single engine and I enjoyed flying the Archer as a rental for no more then $80 a hour wet. I was on my way to an IFR rating when the costs started to over take my budget and instead of attempting to be a hack IFR pilot barely making minimums, nor did I want to just fly patterns for an hour, I stepped away from my pilot activities. I think t'all that do this a lot are looking through rose colored glasses when you even talk about GA. it died a long time ago.

It should be referred to as LAA or Limited Access Aviation. Costs are going in only one direction, up and at a pace that will eventually cause a final stall, spin, and crash of what resembles GA. they days of Aunt Bee getting into a Cessna 150 and learning to fly are gone, yet that should have been the model industry people fought to keep. Now we think one is getting a good deal on a Piper, because it is a little less then a Cessna at $400,000.

There is not a day that goes by that i don't look up and watch a plane go by and remember that feeling. I wit here on the approach path to GSP and listen to jets coming and going and dream. Then I read a review like this and get that slap in the face that says flying is not for the General public at $260 an hour for a typical, basic four passenger plane. Aviation does not want the General Public interested in flying at $400,000 or $350,000 or over $100 an hour just to learn to fly in old worn out planes. I love flying and I am sad to be around as it fades from the public stage.

Posted by: Justin Hull | April 25, 2014 8:46 AM    Report this comment

Seems to me many in GA can't see the "runway for the trees"? Until the ENTIRE GA industry gets off this "engineering/technical" brilliance and jargon, and finally openly accepts that fact the real PROBLEM (flight school competence) is in growing future aviation consumers, all else is mote. And YES, it's not for ANYONE, demographics aside, who feels the benefit is not equal to or greater than the cost - REALITY?.

Posted by: Rod Beck | April 25, 2014 9:31 AM    Report this comment

$400,000 airplanes are well out of the reach of most of us. If I won the lottery I might buy a $400,000 airplane but it sure wouldn't be a Piper Archer. On the other hand, the guy in the next hangar just bought a mid sixties 172, mid time engine, good steam gauges, basic IFR, very good paint and interior for less than $30.000. He is one happy camper.

Posted by: Richard Montague | April 25, 2014 10:29 AM    Report this comment

Richard, that a pilot can still get a $30,000 aircraft is a good thing. My viewpoint was not so reflective of that situation, but the extended view of what eventually replaces that 40,50, 60 year old airframe. The pool of available planes will slow shrink along with the pool of capable pilots (both in income and skill) and as it does, the replacements are bring way priced out of the common market. As David pointed out, in 1979 Piper sold as many Archers in two weeks as they did not for one year.

Does that not concern anyone of power in the industry or are have they become somewhat insulated having just been around so long. I realize it is a poor comparison, but we are asking young pilots who may want their own plane to be required to look at old airframes, old panels, worn out engines, basically the equivalent of them looking at 1950's Fords and Chevy's and saying be glad you got even that choice. Maybe aviation is not for everyone, but it could be for more (like it use to be) if it ever were to be affordable. However, that ship sailed and wont ever come back.

Posted by: Justin Hull | April 25, 2014 11:21 AM    Report this comment

Dave, there are a lot of ways to slice these numbers and although I don't have current data on routine maintenance like oil changes and filters, owner surveys reveal that these costs aren't a driver. I'm going to do another survey shortly.

At a glance, the diesel economics shouldn't work. After all, here's an engine that costs more than twice as much as the equivalent gasoline engine, has only 60 percent of the service life and requires a $7000 gearbox package just to achieve that. How can this possibly work?

Fuel costs. In Europe--and elsewhere--the fuel cost difference between avgas and Jet A and the fact that the diesel burns a third less fuel drives it well into the black. Those curves are pretty relentless and would be little affected by costs of oil changes and filters, almost no matter how high they are. Even if you remove the gearbox requirement for the 1200-hour 2.0S, it shifts the operating costs only about $6 for the life of the engine. In the U.S., with avgas at $7 and Jet A at $5.50, the diesel comes close to working, but it's not as clear cut as in Europe.

For the Lycoming, by the way, Bluebook gives a $20,000 overhaul, but that's a tad low. Furthermore, operators say mag and cylinder maintenance on the way to TBO will require between $5000 and $6000 so I used $26,000 all in for the Lycoming. You can reduce that by $6000 and not change the directionality much at all.

Dispatch reliability is a mixed bag. The Centurions had early teething pains and now seem to be getting better. They have the advantage of electronic diagnostics. Lycomings have issues with fouled plugs, mags and valve morning sickness. The core of the Centurion--cylinders, heads, valves--doesn't seem to require intermediate work, but pumps, filters, connectors, alternators and the like might.

Posted by: Paul Bertorelli | April 25, 2014 11:41 AM    Report this comment

Enough already with the "on-one-hand-is-maybe-bad-but-on-the-other-hand-is-really great". I am not buying it. The Piper DX Diesel and others alike are design aberrations in any market. That is, in the US, China, EU or Timbuktu. The other complaint is that we are flying decrepit aircraft. Have any of the complainants heard about 100 hour and annual inspections or refurbs?

Posted by: Rafael Sierra | April 25, 2014 12:20 PM    Report this comment

Hey Rod, plea$e help me out. $ank you!

Posted by: Rafael Sierra | April 25, 2014 12:27 PM    Report this comment

HI Rafy: What$ i$ it you$ want to know $

Posted by: Rod Beck | April 25, 2014 12:58 PM    Report this comment

'Does that not concern anyone of power in the industry or are have they become somewhat insulated having just been around so long.'

This comes up often. My view is that when times show a downturn in economics, interest and opportunity that used to be robust and spread more evenly, those still in the game pull in or circle their wagons, so to speak, to stay viable and are not as concerned about universal or broader effects, even in their own industry. We all sing in the choir here about GA, but it is becoming more and more fragmented and uniquely independent, imo, whether due to the lack of nationalism or the lack of building all-inclusive perspectives, as of the past.

We have diesel, electric, UAV's, many different types of materials from so many more countries nowadays building aircraft, (but still not utilizing mogas to broader degrees) plus technology driving change at mach speeds, I'm just happy I can stay in the game for now with me' little homebuilt, or I'd be on the sidelines, too.

Posted by: David Miller | April 25, 2014 2:29 PM    Report this comment

After reading all comments, I must say that american pilots are spoiled. You guys are saying that GA in states is dying, take a look at Europe. My country has population of 36 million and only about 2000 registered GA airplanes. At my airport avgas is $13.5/gal; JetA $6.75/gal and auto diesel $6/gal. Tell me diesel does not make sense.
Additionaly we pay airway fees and approach fees for aircraft above 2 tons. Plus handling charges at most airports, whatever the weight.
We'll keep on flying anyway:)

Posted by: Mike J | April 25, 2014 2:48 PM    Report this comment

" After reading all comments, I must say that american pilots are spoiled." We, Americans, are not spoiled - we are refusing GA scenarios similar to what you have in Europe. Some of us do not like the downward trend and we are working on improvements for public benefit.

Posted by: Rafael Sierra | April 25, 2014 3:46 PM    Report this comment

"We, Americans, are not spoiled - we are refusing GA scenarios similar to what you have in Europe. Some of us do not like the downward trend and we are working on improvements for public benefit."

By all means keep up the fight. I admire the way you guys in US stand together for the cause. I am also jealous about your GA infrastructure and overall operating conditions.
But avgas is "dead" pretty much everywhere outside US. The sooner we (You) accept it, the better the chance for developing economical engine for all GA everywhere in the world.

Posted by: Mike J | April 25, 2014 5:49 PM    Report this comment

Why must pilots continue to train in aircraft that seat 4?

Posted by: Samuel Walsh | April 25, 2014 6:49 PM    Report this comment

Why must pilots continue to train in 4 place aircraft? (multiple choice)

1. They get use to W/B problems they'll later encounter when renting 4 plane aircraft
2. Many students have forgone the "Slimfast" diet.
3. He/she likes to take his "family" along on training flights - The Simpsons?.
4. The flight school SOLD all their J-3's & Aeronca Champs in 1962 (fabric didn't pass punch test) ?
5. The "CFI" weights 437 lbs*.and sits (instructs from) the rear seats?

*NOTE: If choosing # 5, consult the "A/C" W/B graph

Posted by: Rod Beck | April 25, 2014 10:56 PM    Report this comment

"Why must pilots continue to train in 4 place aircraft? (multiple choice)"

Added responses ...

1. Cessna stopped building two seat trainers nearly 30 years ago, and no one else has built any in quantity since.

2. Most basic "4 seat" airplanes are, in reality, 2+2 (to borrow a term from the car world). Few if any will carry 4 full sized adults and full fuel. The back seats are mainly for kids, or for taking people on short, local sightseeing flights.

3. Most people rent 4 seat planes after they get their license, so why not train on what you're going to fly?

4. Even basic 4 place planes are considerably roomier, more comfortable, and usually better equipped than any basic 2 seat trainer. Even when brand-new, no one would have called the Cessna 150/152 interiors anything other than "Spartan".

Posted by: Eric Gudorf | April 26, 2014 8:39 AM    Report this comment

5. The older one gets, the smaller the cabin gets...long story here.

Posted by: Rafael Sierra | April 26, 2014 9:04 AM    Report this comment

Eric; On a more SERIOUS note; the LSA clan has the "product" to replaced the C-150/152 (1959-85) of which Cessna produced 31K variants. Problem is NOT one has a 4 place (upsell) as Cessna did; 172 182,206,210, etc and probably won't - ROI/investment (risky?) doesn't make cent$. That said, ALL your points make (logical) total cent$!

Posted by: Rod Beck | April 26, 2014 9:05 AM    Report this comment

Dave Miller, could you explain what you mean by "or the lack of building all-inclusive perspectives, as of the past."? I am sincerely intrigued.

Posted by: Rafael Sierra | April 26, 2014 12:21 PM    Report this comment

Hi Rafael, busy day here...... Attitudes in hindsight would have been better than perspectives. When I think of the times from my youth when society didn't seem so intolerant and divided, people actually liked living near airports, never heard a complaint. One of many examples I could cite was the go-cart track we kids rode our bikes to that offered a coupon for a free intro flying lesson at the airport if you beat a certain time, etc.

It's not very applicable to the blog, but the constant fight we have now for damn near everything it seems - case in point, the post following your query - I just feel that groups, associations, schools and individuals were more focused then for the good of the whole than we are today. I may be entirely wrong, but I guess I did a bit of pining for my past with my comment.

Posted by: David Miller | April 26, 2014 8:23 PM    Report this comment

Dave, your comment "focused then for the good of the whole than we are today." is correct. It seems to me that as GA's industrial complex shrinks instead of combining resources for the "good of the whole" that there is a growing self-serving individualistic behavior, a way of survival for some, resulting in detrimental and diluted nationalistic believes. I surmise that US companies being sold to foreign interests represent an un-American mindset and in doing so that we are loosing our nationalistic pride. Thanks for responding.

Posted by: Rafael Sierra | April 26, 2014 11:53 PM    Report this comment

Mr. Bertorelli; In 1992, a great film; A Few Good Men, Jack Nicolson portrayed a Marine Colonel, and quoted a rather poetic line; "You can't handle the truth"! Was my last comment offensive; I guess it was by your subjective standards. And yes, you can "delete" any comments you may disagree with - it's (AvWeb) your baby. And with that, sir, I can clearly see who's comments get published and whose do not. After reading some of your "technically" interesting articles, the responders here, frankly, and possibly yourself, continue and FAIL to see that GA is its own worst enemy. THIS IS MY FINAL COMMENT - You and the others who are in denial, enjoy GA (recreational) and its passion while its still here - it will be over within a few decades or so.

Posted by: Rod Beck | April 27, 2014 6:14 AM    Report this comment

I don't particularly care if messages agree with me or anyone else. But we do ask that they refrain labels, name calling and the questioning of another poster's intent or intelligence. A couple of your messages didn't meet that standard, so they were removed.

In any case, you are more than welcome to post here under those guidelines.

Posted by: Paul Bertorelli | April 27, 2014 9:03 AM    Report this comment

Paul; And I assume that means it goes BOTH ways? Thank you.

Posted by: Rod Beck | April 27, 2014 9:30 AM    Report this comment

even at the 4 GPH that's about $20 an hour, probably be more like $10 an hour. The gas O-360 is well proven and usually goes to the 2,000 TBO and longer for flight schools, parts and mechanics easily obtained and at every airport, financially just can't see how it makes any since going diesel.

Posted by: MICHAEL PLANCHAK | April 28, 2014 3:57 AM    Report this comment

Michael: Diesel makes perfect sense when there's no avgas available to burn. See today's story about the latest petition by the Friends of the Earth. Much like the C-162, avgas has "no future."

Posted by: Tom Yarsley | April 28, 2014 7:35 AM    Report this comment

They are not happy til we are not happy??? The petition is a real threat. Should it ever become effective, then I would predict that GA in the US, CHINA, EU and Timbuktu has NO FUTURE. I wonder how long it will take for the majority of the stakeholders, the users in the US to react preventing the "petition" from devastating what is left of the avgas dependant industry.

Posted by: Rafael Sierra | April 28, 2014 8:07 AM    Report this comment

It seems that each of these diesel conversions installs a diesel of lower power than the gasoline engine it replaces. Why is that?

This conversion basically puts the airframe/powerplant combination more comparable to the Warrior than the Archer doesn't it?

Posted by: TIM MORRISON | April 28, 2014 8:35 AM    Report this comment

Weight. A Diesel engine has to be heavier to contain combustion pressures but that's a tradeoff against max power output. It's an issue in cars, but not as acute as in airplanes.

So, a little less power and a little more weight. You know the rest. It's about 80 pounds in the Archer.

Posted by: Paul Bertorelli | April 28, 2014 8:59 AM    Report this comment

A little less power, a little more weight, a lot more expensive. But not to worry, we diesel and we green. If it would not be so serious I would think of it as a joke.

Posted by: Rafael Sierra | April 28, 2014 9:32 AM    Report this comment

A CPC, or most any other North American school, isn't going to buy centurion powered anything until Cessna forces them to and I don't see the sister company of Lycoming giving up a Lycoming option. Most schools won't change engines until they have to. Lycoming engine maintenance is one of their core functions.

If you have an A&P with years of working on that engine in Mercedes cars, you might look at this idea, but otherwise it's not attractive. Look at what happened with the DA20. That plane was/is a vastly superior trainer which is cheaper, more fun to fly, and safer. The main reason it doesn't sell - it's not the same engine. It's different. Your customer and instructor are many times less likely to die in the DA20 and you can make more money while undercutting your competition, but if you run a school you will run into some different issues than you are used to (different plane means different issues), it will interrupt your daily grind, and you will want to get rid of it. Why? Because you are a type of person who reacts that way because all people who run schools are that type.

Posted by: Eric Warren | April 28, 2014 10:18 AM    Report this comment

Those little flyeco diesels interest me - just over a kilo per horsepower but much less weight in fuel required due to their spectacular fuel efficiency. Keen to see you flight review Paul!

Posted by: John Hogan | April 28, 2014 12:00 PM    Report this comment

John, I actually did fly it at Aero, just briefly. At cruise, it was burning 1.8 GPH at about 95 knots. What...about 52 MPG. In an FK9 LSA.

Posted by: Paul Bertorelli | April 28, 2014 1:22 PM    Report this comment

52 mpg? Phenomenal. There is the affordable flying we're talking about.

Posted by: John Hogan | April 29, 2014 2:12 AM    Report this comment

I don't have prices on the engine, but the problem with small diesels in airplanes that don't burn much gas is that the economics can't necessarily be made to work on paper.

I've talked to a couple of LSA manufacturers about this. If, like the Centurion, the engine costs more than twice as much as a Rotax does and saves 30 percent in fuel, it's 30 percent of a much smaller total number.

Take the the Pipistrel Alpha trainer, for instance, it's burning about 3.5 GPH in cruise with the Rotax 912 UL, so the FlyEco would save a little over a gallon an hour. In total dollars, the investment might not be worth it. According to the specs, it's 49 pounds heavier than the Rotax--a huge hit in an LSA.

The power densities run like this: The Rotax is at .59/lb, the Centurion at .52 and the FlyEco at .42.

Posted by: Paul Bertorelli | April 29, 2014 5:56 AM    Report this comment

Actually, wouldn't that be 52 Knots per gal or 60 Mpg?

Posted by: Richard Montague | April 29, 2014 7:14 AM    Report this comment

Well, no, actually. Mileage is expressed as distance per gallon, not speed per gallon.

So to be perfectly accurate, it ought to be 52 nautical miles per gallon. Among friends here, I assumed--perhaps incorrectly--that nautical miles is a given.

Posted by: Paul Bertorelli | April 29, 2014 8:36 AM    Report this comment

52 nmpg..That's still pretty good...even better than 52 smpg. Believe it or not, some of us do still fly airplanes with airspeed indicators calibrated in mph; after a while, you get pretty good doing 15% corrections in your head :-)

Posted by: A Richie | April 29, 2014 8:57 AM    Report this comment

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