Diesel V8 flys
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Yeah, I have driven some really amazing TD cars, but the laws of physics apply equally to all things (except the F22).
Wanna run JetA fine, buy a turbine.
Wanna run JetA fine, buy a turbine.
Unlike a Turbocharged avgas burner, you will not get flying behind one, and I do not imagine many folk would be keen either when they fly over high country like the west of the USA.
Anyone know why?
Anyone know why?
They belch black smoke distress signals and the fuel consumption goes into the ****ter, but generally they can keep running to a degree.
A mixture sweep sorts that but you can have power to divert safely.Join Date: Jun 2001
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They belch black smoke distress signals and the fuel consumption goes into the ****ter, but generally they can keep running to a degree.
If that happened over the mountains, I would ... increase power on t'other engine to compensate.
You wouldn't fly a single over the Rockies now would you Jaba?
Seriously though, once the bugs are ironed out of a new design (which will take several years to a decade) it is likely to be just as reliable as any other design. There is no evidence that a CI TC engine (to give it the strictly correct title) is intrinsically less reliable than an engine with spark plugs.
Last edited by Oktas8; 15th May 2014 at 01:18.
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I can't see any difference really that all engines are compensates for altitude. Turbine or blown are all compensated can't see why this engine won't be any difference when it and if it get certified.
The test will be seen once it starts to fly. I'm sure there will be bugs it's going to be and if they can fix them.
Any one remember the hype over the thunder engine. It preformed better than the turbine engine in a 690 commander as I recall. Then sold some stc certified now gone and stc removed.
Time will tell.
Cheers
The test will be seen once it starts to fly. I'm sure there will be bugs it's going to be and if they can fix them.
Any one remember the hype over the thunder engine. It preformed better than the turbine engine in a 690 commander as I recall. Then sold some stc certified now gone and stc removed.
Time will tell.
Cheers
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Andy
The inlet of a turbo scroll is convergent. This is before any gases are released across the turbine. Then the scroll continues to convergent path till the end this is to keep the velocity up across the whole of the disc to keep the forces equal across the centre bearing. Aircraft turbo centre bearings are made of aluminium any force that's not centralised will wear the bearing out extremely fast.
Px is distributed equally than as you say there would be no use for the scroll to continually decrease in size.
It dose not matter if it avagas engine Diesel engine or a gas turbine from an small Alison 250 to rb211 they all work on the small priceable velocity 1st the px change across the disc.
Now late model turbos in cars use variable vanes instead of a waste gate. The opening and closing of the vanes changes the velocity onto the disc.
In a gas turbine the same is used on the compressors to stop compressor stall on start up and low speed.
Cheers
The inlet of a turbo scroll is convergent. This is before any gases are released across the turbine. Then the scroll continues to convergent path till the end this is to keep the velocity up across the whole of the disc to keep the forces equal across the centre bearing. Aircraft turbo centre bearings are made of aluminium any force that's not centralised will wear the bearing out extremely fast.
Px is distributed equally than as you say there would be no use for the scroll to continually decrease in size.
It dose not matter if it avagas engine Diesel engine or a gas turbine from an small Alison 250 to rb211 they all work on the small priceable velocity 1st the px change across the disc.
Now late model turbos in cars use variable vanes instead of a waste gate. The opening and closing of the vanes changes the velocity onto the disc.
In a gas turbine the same is used on the compressors to stop compressor stall on start up and low speed.
Cheers
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Andy,
Ahh but the mixture knob fixes that 
A sweep will find the best of a bad day.
Yr Right, have a think about what it takes to run a compression ignition piston engine at altitude and what happens with a substantial loss of boost from a simple coupling, not a turbo failure even.
They belch black smoke distress signals and the fuel consumption goes into the ****ter, but generally they can keep running to a degree.
A sweep will find the best of a bad day. Yr Right, have a think about what it takes to run a compression ignition piston engine at altitude and what happens with a substantial loss of boost from a simple coupling, not a turbo failure even.
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Jabba
The penny has just dropped. Are you saying that at altitude not enough air means not enough compression to light the fire? Would sort itself out at lower altitudes but over the Seirra Nevada the silence would be frightening............
The penny has just dropped. Are you saying that at altitude not enough air means not enough compression to light the fire? Would sort itself out at lower altitudes but over the Seirra Nevada the silence would be frightening............
I have heard that on the SMA it is possible for the diesel fire to go out on descent, which is why I believe they have a minimum descent power requirement.
On a liquid-cooled engine though, this is less of an issue because the cooling system can be thermostatically controlled to limit the rate of cool-down.
Having said that, since you can start and idle a modern diesel engine at the top of most mountains (FL100-120) I'd say the chance of losing ignition for a diesel engine because an inlet hose burst or fell off is pretty remote, especially under any reasonable power level that still remains. The beauty of a diesel engine though is that it doesn't rich misfire, hence the black smoke.
On a liquid-cooled engine though, this is less of an issue because the cooling system can be thermostatically controlled to limit the rate of cool-down.
Having said that, since you can start and idle a modern diesel engine at the top of most mountains (FL100-120) I'd say the chance of losing ignition for a diesel engine because an inlet hose burst or fell off is pretty remote, especially under any reasonable power level that still remains. The beauty of a diesel engine though is that it doesn't rich misfire, hence the black smoke.
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Well ive got to say ive never heard or seen an induction tube fail or come undone. That just comes done to simple maintenance procedures. Also never had a complete turbo failure ethier they give signs well before they die.
What may be interesting is if they able to put it in a px airframe and how they get a larger blower into the engine cowl.
and with one control it will be idiot prove lol
Cheers
What may be interesting is if they able to put it in a px airframe and how they get a larger blower into the engine cowl.
and with one control it will be idiot prove lol
Cheers
Interesting, a question for those who have flown behind either the SMA or the Centurion. With engine control, is the engine speed governed by power settings or pitch settings? I have always assumed that governor settings would be controlled by fuel input. In effect, if you go from cruise to climb, engine senses rev change and automatically inputs more fuel. Till WOT, pitch remains at cruise setting until revs start to drop then pitch changes to maintain revs....automatically.....autothrottle for lighties?
I am an avgas fan and could not be botherd using google....so my question is....Can you run your Toyota Land Cruiser on JetA or could you run your PT6 on automotive diesel?
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sms777:
In both cases, the answer is yes - but in both cases nearly all the manufacturers recommend against it.
It all comes back to the fact that each fuel is refined for a specific purpose, and refined to fuel specifications that apply to each type of fuel.
In the case of the Landcruiser - older diesel Landcruisers (with mechanical fuel injection) run quite happily on a mixture of kerosene and crankcase oil (not more than 5% oil).
However, newer models with electronic fuel injection have much tighter parameters for the fuel viscosity, and the ECU can sometimes reject the fuel once those parameters are exceeded. In other words, the engine will refuse to fire and a fault code will show.
I am not sure if JetA would be outside the viscosity parameters of regular road diesel in an electronically-injected Landcruiser. There is a difference in SG between the two fuels.
As for using diesel in a PT6 - yes, you can, but most manufacturers do not recommend it, because of the high possibility of the diesel fuel gelling or freezing.
Diesel fuel can be used in low level aviation operations, if the engine manufacturer approves.
JetA has lubricity improvers for improved aviation engine life, and other additives that allow it to still function satisfactorily as a fuel at the extremes of temperatures encountered in aviation at higher altitudes.
This question has been discussed before at length, on this forum - http://www.pprune.org/tech-log/444111-diesel-fuel.html
I am an avgas fan and could not be botherd using google....so my question is....Can you run your Toyota Land Cruiser on JetA or could you run your PT6 on automotive diesel?
It all comes back to the fact that each fuel is refined for a specific purpose, and refined to fuel specifications that apply to each type of fuel.
In the case of the Landcruiser - older diesel Landcruisers (with mechanical fuel injection) run quite happily on a mixture of kerosene and crankcase oil (not more than 5% oil).
However, newer models with electronic fuel injection have much tighter parameters for the fuel viscosity, and the ECU can sometimes reject the fuel once those parameters are exceeded. In other words, the engine will refuse to fire and a fault code will show.
I am not sure if JetA would be outside the viscosity parameters of regular road diesel in an electronically-injected Landcruiser. There is a difference in SG between the two fuels.
As for using diesel in a PT6 - yes, you can, but most manufacturers do not recommend it, because of the high possibility of the diesel fuel gelling or freezing.
Diesel fuel can be used in low level aviation operations, if the engine manufacturer approves.
JetA has lubricity improvers for improved aviation engine life, and other additives that allow it to still function satisfactorily as a fuel at the extremes of temperatures encountered in aviation at higher altitudes.
This question has been discussed before at length, on this forum - http://www.pprune.org/tech-log/444111-diesel-fuel.html
The Su-25 could run on diesel for up to 4 hours. From what I understand it had a toolkit that allowed the pilot to make off field alterations to facilitate this to allow unscheduled front line landings (assuming on roads) to refuel from vehicle diesel and limp home. I don't think many commercial jets or turboprops would have this ability.
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If you can burn it you can run it in a turbine. Some aircraft with pt6 alow you to run Avgas for a short time. This limits however the o/h periord but
I've seen a Alison 250 modified to run on coal dust. Not for aircraft use but
Cheers
I've seen a Alison 250 modified to run on coal dust. Not for aircraft use but
Cheers
FADEC might be the temporary saviour of traditional engines, but as I see it, there will be a day where the oil companies simply refuse to manufacture a fuel that sells in miniscule volumes compared to Jet A and even automotive fuels. On top of that you need special distribution systems. I can see Avgas being priced out of the market in my life time.
In many countries you cannot get Avgas at any price. In that regard I think diesels are the only way forward. Aerodiesels are still in their infancy today, but I believe given enough time and money the problems will be resolved. They simply have to be.
In many countries you cannot get Avgas at any price. In that regard I think diesels are the only way forward. Aerodiesels are still in their infancy today, but I believe given enough time and money the problems will be resolved. They simply have to be.
Many engines will run on anything combustible, the real issue is how long it will put up with it, what affect it will have on it, how practical is the fuel, such as power output, supply, weight etc... The GE LM2500 is a derivative of the CF-6, it's used in the ANZAC frigates, but it is modified for this use with marine fuels.
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With engine control, is the engine speed governed by power settings or pitch settings? I have always assumed that governor settings would be controlled by fuel input. In effect, if you go from cruise to climb, engine senses rev change and automatically inputs more fuel.
The FADEC controlled manifold pressure (via turbo wastegate), fuel flow (via injector timing) and propeller pitch (via oil valve). From memory there were about sixty inputs into the FADEC to tell it what was going on in & around the engine.
The power lever angle is resolved into an electrical signal, so the FADEC knows what power is being requested. Each power setting is associated with a particular RPM, so the propeller control valve would move to change blade angle to change RPM to match the target value. Entering a climb, reducing speed, would cause the FADEC to command a smaller blade angle to maintain RPM. That doesn't set power however. The FADEC could set power independently of RPM, by adjusting MAP and injector timing.
Fuel flow would be set by the FADEC according to a specific schedule - obviously depending on inlet manifold temperature & pressure, fuel type (diesel, JetA, JetA1 etc), and many other variables. The FADEC would adjust fuel flow and manifold pressure to maintain the commanded power setting at any given TAS, altitude and RPM.
It worked very much more smoothly than traditional engines with three levers.
I once had a propeller control valve malfunction in flight. RPM was cycling between about 1200 and 2300 RPM, with a period of 20 seconds or so. At first I thought it was a sputtering engine, but power output was rock steady and there was no yaw. Strange feeling! But it illustrates the relative independence of RPM and power output in these engines.
Obviously I would be more impressed by an engine that didn't fail at all. But, given that was early days of the Thielert engine, things have improved since. It is IMO the way of the future.
Last edited by Oktas8; 17th May 2014 at 23:16.