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May 8, 2008

Wanted: Aerodiesel from Honda

By Paul Bertorelli

Carl Spatz and Ira Eakin—the two legendary leaders of U.S. air power in World World II--just got it all wrong when they decided to bomb the German ball bearing factories at Schweinfurt in 1943. What they should have been bombing is the factories that make those little skinny spring washers that the Germans can’t seem to build so much as a toy wagon without using by the gross. The war would have ended a year earlier.

I was reminded of this today when my correspondent Stan Fetter wrote this note about his experiences in repairing a Thielert diesel’s all-critical clutch: “There are a bunch of spacers in there, and if any of that stuff comes apart the whole thing has to go back to the factory...Had a new one on the bench and the tool guy picked it up and moved it, and stuff went everywhere.”

Been there…and the t-shirt is now a shop rag. I have a couple of motorcycles, a BMW and a Honda. To service the fuel pump and filter on the BMW, you need a pair of hemostats—no kidding, that’s what the shop manual says—to squeeze off the fuel hoses while you worry the thing out the side of the fuel tank, being careful not to trash the $400 fuel gauge sender. And don’t forget the special clamps which you must replace. On the Honda, the same assembly drops out of the bottom of the tank in five minutes. Buy the clamps at NAPA.

This aside is central to the problems Thielert is having with its aerodiesel. The thing requires a lot of wrenching—replacement of the gearbox and clutch assemblies, fuel pumps, alternators and so on. And it’s not simple wrenching, thanks to the German penchant for using two spacers where one will do, a spring hidden in an invisible blind hole that rockets across the shop and careens off the bench grinder and disappears before you even knew it was there. And great clouds of those damn flat washers which are always left over after you’ve reassembled the part without the missing spring because they’re out of stock and the parts guy says they leave them out, too.

Which brings me to this: What’s needed here is for Honda to stop screwing around with four-cylinder gasoline engines and to get busy with aerodiesel. For reasons related to culture, economics and predisposition, the Japanese haven’t been big on diesel engines for cars. In fact, Honda is expected to launch its first next year. By dint of long experience—the Germans own the diesel car market—the Germans have diesel pretty well figured out. It will be daunting for others to catch up. But to a degree, the Germans are victims of their own success when it comes to building things that are easily maintainable. They tend toward in-the-box thinking with regard to repairing things. The Japanese have proven to be better at this, at least in cars and motorcycles. It would be intriguing to see their version of a practical aerodiesel.


Comments

Yep. We need Honda to develop a simple, economical diesel engine for aircraft, with low cost for aircraft owners (a Theirlet costs what, 62K, for an install? That ain't low cost!). The price has to be low enough so that aircraft owners will be able to replace the avgas engine economically.

And DON'T go with full FADEC!. I don't mind partial control over the engine with computer, but leave a backup system that isn't dependent on computers.

Wouldn't hurt if they did some developing of some gasoline engines for aircraft...maybe one that run better with automotive gasoline...I'd be afraid to run an aircraft these days, what with ethanol and such added to the gasoline.

posted by George Rambo on May 9, 2008   (report abuse)

And while they're at it, why not develop an electric aero engine powered by a small gasoline aux generator in the baggage locker? Honda already makes the latter.

posted by nicholas budd on May 9, 2008   (report abuse)

hehe, you're right paul, we operated a c-172 with a 1.7 thielert (failed in flight) then a 2.0 and the bloody clutch came apart(literally) 3 times in 100 hrs. diesels are here to stay, we just got to work the last few bugs out, and the japs are probably the peeps to do it!

posted by john greif on May 10, 2008   (report abuse)

Might I suggest the French (particularly PSA) who have a long tradition of cheap, lightweight and very durable diesels; or Volvo Penta which has a long tradition in aero engines, and good experience with diesel on both the marine and automotive side?

posted by Bram Smits on May 13, 2008   (report abuse)

the problem with honda using gasoline motors in airplanes is that their motors are much more powerful at higher rpm settings, not to say that honda couldnt create a great aviation motor. i am a Honda automobile employee and truly believe in Honda's product and innovation. i have been employed at honda dealerships for 10 years now. they have grown in leaps and bounds. i think Honda and Ge really need to concentrate on the possibility of a hybrid type engine. use gas (but a lot less of it)and electricity, very similar to a civic hybrid.

posted by MICHAEL SULLIVAN on May 13, 2008   (report abuse)

I can't see how a hybrid makes sense. The advantage of a hybrid in a car comes from the ability to shut off the engine while idling and battery charging during braking. The disadvantage is weight, which matters far more to an aircraft than a car. Maybe leave out the extra batteries and use solar panels to provide some of the energy in flight? But would this really overcome the efficiency and weight penalties of a gas engine/electric motor system in anything larger than a motorglider?

posted by Alex Frakt on May 13, 2008   (report abuse)

Hybrids are primarily aimed at levelling the "peaks and valleys" of driving. Aviation does not have the same type of demand curve - typically short high load climb, extended part load cruise and short low load descent. The battery would only benefit from the descent phase where we need to dissipate excess energy. Self discharge of the battery would limit the amount of energy that could be "recycled" in the climb phase of the next flight.

I consider that the internal combustion engine is firmly entrenched, but needs to reap the benefits of improved technology, whether diesel or petrol. Turbine engines, with improved materials may offer the best long term solution because they can burn just about any liquid fuel and do not waste energy on reciprocation.

posted by simon lewinson on May 13, 2008   (report abuse)

alex is correct. K I S S

posted by john greif on May 13, 2008   (report abuse)


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