Another Diesel engine
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It is not the Engine... It's the Fuel.
Aircraft Avtur Type Fuels
These engines do not burn a "Diesel Fuel". The recent developments are targeted at using Jet A-1, JP-5 or JP-8 as a fuel.
That is the problem, as these aircraft fuels are designed for continuous combustion and do not have a controlled Cetane Index. Cetane number - Wikipedia, the free encyclopedia
Among other things this shows as a variable ignition delay WRT Crank Angle. The wide range of Cetane Index Nos from various Fuel Suppliers results in a wide spectrum of performance.
Many, many millions have been expended on this over the last 20 or so years. As yet none of these developments has resulted in a truly usable aircraft power-plant.
As aviation gasoline (Avgas) is gradually withdrawn from use and Road Car Fuel (Gasoline) has an ever increasing Alcohol Fraction, more money will be expended in trying to produce a usable small aircraft Avtur power-plant.
Check out what is going on in the UAV world.
A really interesting workspace!
Charlie
These engines do not burn a "Diesel Fuel". The recent developments are targeted at using Jet A-1, JP-5 or JP-8 as a fuel.
That is the problem, as these aircraft fuels are designed for continuous combustion and do not have a controlled Cetane Index. Cetane number - Wikipedia, the free encyclopedia
Among other things this shows as a variable ignition delay WRT Crank Angle. The wide range of Cetane Index Nos from various Fuel Suppliers results in a wide spectrum of performance.
Many, many millions have been expended on this over the last 20 or so years. As yet none of these developments has resulted in a truly usable aircraft power-plant.
As aviation gasoline (Avgas) is gradually withdrawn from use and Road Car Fuel (Gasoline) has an ever increasing Alcohol Fraction, more money will be expended in trying to produce a usable small aircraft Avtur power-plant.
Check out what is going on in the UAV world.
A really interesting workspace!
Charlie
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The cetane issue is a mainly theoretical one. All major piston diesels (Thielert, Austro, SMA) are certified for the common avtur types. In fact, Austro and IIRC SMA aren't even certified for EN590 diesel. The engines appear to make TBO/TBR without major problems.
In fact, Thielert and Austro sell to the UAV world, it's basically what has kept Thielert afloat for the last few years.
Car engines are not ideal for airplanes but they do work quite well. The main issue is long term availability of parts. By the time they get to certification, the car maker has usually moved on to the next generation. Austro is supposed to have spent €45m in adapting the Mercedes engine -- the same model that Thielert used and with fewer modifications, i.e. less weight reduction. SMA have built a very conventional diesel with only custom parts, the result is not that great and the price is insane.
I'd say either car derived engines or a true aero diesel based on the Junkers Jumo 205 design. Deltahawk appear to be closest.
In fact, Thielert and Austro sell to the UAV world, it's basically what has kept Thielert afloat for the last few years.
Car engines are not ideal for airplanes but they do work quite well. The main issue is long term availability of parts. By the time they get to certification, the car maker has usually moved on to the next generation. Austro is supposed to have spent €45m in adapting the Mercedes engine -- the same model that Thielert used and with fewer modifications, i.e. less weight reduction. SMA have built a very conventional diesel with only custom parts, the result is not that great and the price is insane.
I'd say either car derived engines or a true aero diesel based on the Junkers Jumo 205 design. Deltahawk appear to be closest.
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the result is not that great and the price is insane.
IMHO the pricing is insane because all contenders start with a back of a fag packet calculation on how much money they can extract from an FTO doing 500hrs/year, and take it from there. That figure will be £50k to £100k per engine. They are in business, first and foremost.
Lyco sell an IO540 for approx $60k, depending which "cost-plus distributor" you buy it through. The smaller engines cost less. That is your baseline selling price. Obviously nobody would sell a diesel for that, because avtur is cheaper than avgas
If you were to price for the private user you would never bother. And now with tax on private use, the case is totally gone.
