What ever happened to the diesel engine debate?

[quoj]

I have noticed that there have been the odd discussions on diesel engines.They were several years ago and seem to go into quite fine details.It seems like the development of diesel engines for aircraft is like trying to find a cure for cancer: it"s progressing at a snail"s pace. Any "major development" doesn"t lead to much as years then pass and nothing has really changed.In short, however, I am curious to know the pros and cons of a diesel engine for gyrocopters?Can anyone tell me what the main hurdle for diesel engines is?If a simple, reliable diesel engine can be developed for aviation use, will it make much of a difference in terms of reliability, economy and renewable fuel sources?Thank you.Quoj.

[asra]

HiDon,t profess to be an expert, but 2 issue spring to mind;Power to weight ratio is not good in a diesel due to the high forces from the required high compression ratio.Those same high forces due to compression ratio are also more likely to produce problem with torsional vibration.Better off trying to get diesel to go through a turbine!!!!TimC

[quoj]

Hi Tim,Thanks for that. I didn"t think of the vibration issue but yes, I guess old clunker diesels aren"t particularly known for silky-smooth running, are they?I"m guessing that with gyros, there is already enough of a vibration issue, so we wouldn"t want to make it any worse, would we?As for power to weight ratios, is this the main area of development with diesel aviation engines?Any other takers on this topic?Quoj.

[PTKay]

I was and still am a big fan of diesel engines in aviation.I think a lot is running behind the scenes.The Delta Hawk is close to certification, but it lookslike they are surviving on some classified deliveriesfor the UAV military applications.They recently moved to new facilities and got a nice shot of cash.http://www.deltahawkengines.com/Also Wilksch is seeming to move forward, although at a "snail pace".http://wilksch.net/Both of the engines above are two stroke, which addresses boththe power/weight ratio and vibration problems.You have double the number of power strokes per rev than a 4-strokeengine, as well as on "suction" stroke, having only positive pressureon the piston all the time.I think year 2011 will be very interesting for the aviation diesel engines.Also the fact, that Chinese money flew into the Teledyne Continentaldiesel production brings new hopes.Good source of news here:http://www.dieselair.com/index.html

[quoj]

Thanks, PT.That"s a good reference. I"ll check it out.

[dineshkkk]

Over the years, Diesel

[admin]

I think the weight of the engine is still the biggest factor to overcome in nearly all cases a Diesel engine will be somewhat heavier and weight is not our friend for flying.Diesel engines typically based on their power to weight ratio make it nearly impossible to consider.However another factor that must be considered is the actual weight of the fuel.One of the references on the internet shows that Gasoline compared Diesel, depending on the API gravity weighs more.Reference information:-During the summer, Diesel will weigh between 6.951 (API 38) and 7.076 (API 35) pounds per US gallon.Last winter, the diesel weighed around 7.206 (API 32) pounds per US gallon.Regular unleaded gasoline weighs around 6.184 (API 59) pounds per US gallonPremium unleaded usually has an API of 56, or 6.263 lbs per US gallon.Based on the information above you would need to also take into account the weight of the fuel as Diesel weighs more.Having said that often in motor vehicles you get better "mileage" so it might possible to get the same total distance for the same amount of weight, however for aircraft use I don"t know the answer to this question.Thats my 2 cents worth

[PTKay]

Based on the information above you would need to also take into account the weight of the fuel as Diesel weighs more.Having said that often in motor vehicles you get better "mileage" so it might possible to get the same total distance for the same amount of weight, however for aircraft use I don"t know the answer to this question.The "mileage" question is crucial in the aircraft applications.Guess why the biggest customer for the Centurion diesels were the Predator UAV.They call it "mission weight".For the certain distance or endurance to fly, the combined weight of fueland engine in case of diesel beats any turbine or gasoline engine hands down.Especially in economy cruise the diesel engine consumes up to 40% less thanthe gasoline one. So if you intent to go to a certain place you can takeup to 40% less fuel with you, and use the saved weight for your payload.

[asra]

One absolute is that the calorific potential of diesel is much higher

[PTKay]

Check this:http://www.ecomotors.com/Now big money and military grants behind it.

[asra]

Hi AllThe vibration issue associated with diesels is due to the ignition process and that is detonation. Diesels great advantage is torque and the low revs this torque can be accessed. Modern European 2.2litre turbo diesels may only swing to 4000 rpm but they can achieve max torque of around 350 newton meters at around 1750 rpm. All are correct when saying these engines are heavy but there are great advances being made in the area of engine management and programing. I believe chips will be developed that will direct the focus to hi yield torque at lower usable rpm in the not to distant future and when that happens the weight issue will change. In relation to fuel weight domestic diesel has an s.g. around .8, give or take! and domestic auto fuel has an s.g. around the .7s give or take. The fuel weight issue is irrelevant unless you are carrying it by the ton.Cheers Rog

[PTKay]

Regarding vibrations the new Subaru EE20 boxer engine is very interesting.Displacement 1998 cm3Max power 110 kW (150 PS, 148 hp) @ 3600 rpmMax torque 350 Nm (35.7 kgf·m, 258 lbf·ft) @ 1800 rpmIt is very well balanced and compact, like the other soobies we use.It looks like the torque and power curve confirm it would work wellfor a gyro even in direct drive:5 bladed, short prop would run 3000 rpm well @120hp.Nice document to read:http://www.media.subaru-global.com/e..._03_07_02e.pdfSurprisingly the EE20 is s$%^&*sr than EJ20: 353mm vs. 412mmAlso here tons of useful information:http://subdiesel.wordpress.com/boxer...0-engine-info/

[tonydenton]

i was driving along the other day and thinking, about diesel engines, after reading about the fuel being slow burn etc etc and of course good economy and saftey etc. i wonder has any one thought of duel injectors per cylinder???????????spark plugs are done on plane engines mainly for safety i thought,some times 2 smaller amounts can be better than 1 larger amount.

[chook]

Tony, I am driving a 2007 Hyundai Santa Fe which apparently injects a series of bursts at different piston positions during the cycle. Before buying this vehicle I was used to the "standard diesel" which when you started it in the morning caused a black cloud of that distinctive smelling smoke

[tonydenton]

ok thats good.thanks.