Diesel news from Friedrichshafen 2014
The engine (Delta Hawk) is already available for the experimental market.
Not really. They are still playing with “prototypes” in one or two aircraft, they are not for sale as of yet.
I see some similarities between diesel in aircraft and 2 stroke vs 4 stroke for outboard marine engines. For years and years 2 stroke was the norm, 4 stroke never took off for some undefinable reason. Then suddenly over night some 10-15 years ago, “everybody” wanted 4 stroke. Today 4 stroke is the norm for everything above 10-20 HP. In hindsight the reason is rather obvious, earlier 4 stroke engines just wasn’t competitive, the available technology just wasn’t good enough to compete head to head with the dead solid, high HP 2 strokes.
For diesel to take off, it has to be more than a curiosity. A diesel engine has to be able to show more desirable features, real features, on an overall basis than a Lycoming. Today, not a single diesel engine do. For engines larger than 350-400 HP, diesel could be a better option, but not for smaller. At those HPs you also must compete with turbine power.
One of the big ideas for the introduction of diesel engines was the availability of universal fuel i.e Jet/Kerosene/Diesel. The snag is that at this time in the UK, you would have to go to a “big” airfield that caters for Turbo props or jets. That brings with it big landing and handling fees. This goes towards negating any benefit of buying cheaper diesel. With the new range of lycomings able to operate on Mogas or Avgas I see diesels being a side issue for a long time.
I wonder if there are some parallels with motorbikes and garden machinery.
2-strokes have always been at the cheap end of both markets. They make lots of smoke, burn lots of oil, keep clogging up with crap, but they are small and light and cheap. Dirt cheap. The nicer motorbikes are all 4S. The good quality garden machinery is all 4S but costs a lot more (2x more perhaps but as always you pay for quality).
I used to ride 2S Yamahas and later had a 4S Yamaha, and there was no comparison.
I can’t see 2S engines being used in aviation. I used to have to take off the cylinder heads every 2000 miles and scrape off the deposits.
I for one think that set-and-forget thrust is a v. desirable feature as opposed to endlessly wondering whether i should run LOP, ROP, whether I should oversquare, undersquare, overboost and of course most importantly how much is this going to cost me if I screw up. I’d rather spend my time looking outside rather than fiddling with switches and controls.
Oh and if the SMA big six is really going to be TBO versus TBR, I’m the first on the list.
Diesels will compete with turbines the day people will think it’s ok to spend 400k on an unpressurised airframe and 600k on the turbine upfront…
For old skool tech fans I still have a romanian knock-off of the Renault 12 in my garage. 65hp on a good day, weighs half what the Volvo does, same mpg for 75% less power. The upside is that “it works” and you can fix it yourself. Oh and manual mixture control!
I can’t see 2S engines being used in aviation. I used to have to take off the cylinder heads every 2000 miles and scrape off the deposits.
There is a world of difference between the naturally aspirated bottom-price two-strokes in lawnmowers and chainsaws and cheapo motorbikes, and a properly turbocharged two-stroke diesel such as the Jumo 204-208, or the average ship’s engine. I agree the former are utter crap, but the latter are top of the bench. Two-stroke diesel with proper turbo loading are the way to go for piston engines.
A diesel engine has to be able to show more desirable features, real features, on an overall basis than a Lycoming. Today, not a single diesel engine do.
Hm. Pick your own from
1) less litres/hour
2) less cash/litre
(and the “availability” issue will be very temporary. Quite a number of airfields were quick to adopt Total’s U96, given some commercial pressure; there’s not a single reason the same couldn’t happen to jet fuel. Actually, helicopter operators might well make this more than worth its while).
Jet-A is not cheaper than gasoline for the majority of GA engine operators and the amount of fuel saved by the average GA engine operator pays for only a small fraction of the additional capital and maintenance costs for existing diesels.
European taxes do not force worldwide demand for engines.
Rephrase – not cheaper than gasoline for the current majority of operators that are US based. I heard US GA numbers are going one way fast, and it isn’t up…
True, Shorrick, yet Silvaire is right: for the moment, and for several years beyond, GA is largely a US thing, and in the US the price difference is not an argument. And Silvaire is right again that, to many owners/operators, the current extra cost of diesel engines outweighs the advantages. Still, the future is not in petrol, for no single application. It’s either diesel or, perhaps perhaps perhaps, some kind of gas (hydrogen? lpg? cng?) Petrol may last for quite a few years yet, nobody is forced away from it as yet. But for new acquisitions it is not the best of ideas, especially as planes were always considered long-time property.
And the price of buying and operating diesel engines will certainly go down as volumes increase, however slowly, and the initial cost of development and certification gets covered.
