diesel engine 180kg
Discussion
200bhp at 2800rpm is ~508Nm.
so, for various capacities:
2.0 litre engine BMEP = 31.9bar
2.5 litre engine BMEP = 25.5bar
3.0 litre engine BMEP = 21.2bar
4.0 litre engine BMEP = 15.9bar
Now depending on your "duty cycle" (ie how long you expect to stay at that power level) then you can pick a suitable BMEP.
For something like a boat, which will sit at peak power virtually continuously then you need to keep the BMEP as low as possible for durability reasons. Whereas a drag car, that runs for less than 20 sec can obviously run with a much higer BMEP
so, for various capacities:
2.0 litre engine BMEP = 31.9bar
2.5 litre engine BMEP = 25.5bar
3.0 litre engine BMEP = 21.2bar
4.0 litre engine BMEP = 15.9bar
Now depending on your "duty cycle" (ie how long you expect to stay at that power level) then you can pick a suitable BMEP.
For something like a boat, which will sit at peak power virtually continuously then you need to keep the BMEP as low as possible for durability reasons. Whereas a drag car, that runs for less than 20 sec can obviously run with a much higer BMEP
actually i think about an airplane, this is why the wheight restriction.
it would be 10-20 min at ~3000 rpm, then approx 75% of that for a long duration.
but i thought since the redline of the engines use to be at something like 4000 i am not even near that at 3000 or less rpm?
and i hoped to get a little bit more than 200 hp out of an 180kg diesel engine, since 200hp is the absolute minimum for me.
thanks for the input so far!
it would be 10-20 min at ~3000 rpm, then approx 75% of that for a long duration.
but i thought since the redline of the engines use to be at something like 4000 i am not even near that at 3000 or less rpm?
and i hoped to get a little bit more than 200 hp out of an 180kg diesel engine, since 200hp is the absolute minimum for me.
thanks for the input so far!
I hope this doesn't sound too harsh, but i would hope that anyone about to embark on designing an aero powerplant installation is going to use something slighty more scientific than the PH forum for determining suitability for purpose. Most aero engines are massive, unstressed low tech (but high reliability) systems. How you are going to certify for flight say a BOSCH common rail diesel ecu and control system will be interesting??? ;-)
no, it is not to harsh.
i am not yet building an airplane, just thinking about it.
And while thinking about it the question of a powerplant comes up. I am just trying to get an overview what MIGHT be a powerplant that i maybe could use. Of course if i decide on an engine there will be much more in-depth looking into the subject.
best regards
daniel
i am not yet building an airplane, just thinking about it.
And while thinking about it the question of a powerplant comes up. I am just trying to get an overview what MIGHT be a powerplant that i maybe could use. Of course if i decide on an engine there will be much more in-depth looking into the subject.
best regards
daniel
Edited by deepb on Thursday 29th December 14:17
As far as i can tell, the pretty standard solution for selfbuilt aircraft is to simply use an engine that everyone else uses and has been used before. I would imagine the numerous hoops one would have to jump through to certify a new powerplant would be excessively onerous ?
You might find it useful to post in the "Boats, planes & trains" section to gather some opinions on this from the more experienced flyers on PH?
You might find it useful to post in the "Boats, planes & trains" section to gather some opinions on this from the more experienced flyers on PH?
where is the fun to use something everybody else uses? 
the engine doesn't have to be certified in experimental aviation.
there are virtually no diesel aircrafts in this power range available (there are some aircraft diesel engine manufacturers around, their engines are even certified, but at ridiculously high costs.
I am not happy with the standard auto-engine conversion in experimental aircraft (Mazda Rotarys often used) because of the gearbox and the problems with them.
With a Diesel engine i might not have to use a redrive, because it has the highest torque in low rpm anyway.
And with the advance of Diesel engines in the last years i thought this mitght be an option.
best regards
the engine doesn't have to be certified in experimental aviation.
there are virtually no diesel aircrafts in this power range available (there are some aircraft diesel engine manufacturers around, their engines are even certified, but at ridiculously high costs.
I am not happy with the standard auto-engine conversion in experimental aircraft (Mazda Rotarys often used) because of the gearbox and the problems with them.
With a Diesel engine i might not have to use a redrive, because it has the highest torque in low rpm anyway.
And with the advance of Diesel engines in the last years i thought this mitght be an option.
best regards
There was a radial 2 stroke diesel for aircraft use. Looked pretty good. Do a quick google and you should find it. Came as a 4 cylinder single row or 8 cylinder 2 row engine. Not sure of the weight though........
Oh and if you want something different but more PH then how about a ls1???
heard there are a few in the US trying to get these certified!
Oh and if you want something different but more PH then how about a ls1???
heard there are a few in the US trying to get these certified! Edited by chuntington101 on Thursday 29th December 16:45
deepb said:
where is the fun to use something everybody else uses?
the engine doesn't have to be certified in experimental aviation.
there are virtually no diesel aircrafts in this power range available (there are some aircraft diesel engine manufacturers around, their engines are even certified, but at ridiculously high costs.
I am not happy with the standard auto-engine conversion in experimental aircraft (Mazda Rotarys often used) because of the gearbox and the problems with them.
With a Diesel engine i might not have to use a redrive, because it has the highest torque in low rpm anyway.
And with the advance of Diesel engines in the last years i thought this mitght be an option.
best regards
maybe a subaru boxer diesel !!!the engine doesn't have to be certified in experimental aviation.
there are virtually no diesel aircrafts in this power range available (there are some aircraft diesel engine manufacturers around, their engines are even certified, but at ridiculously high costs.
I am not happy with the standard auto-engine conversion in experimental aircraft (Mazda Rotarys often used) because of the gearbox and the problems with them.
With a Diesel engine i might not have to use a redrive, because it has the highest torque in low rpm anyway.
And with the advance of Diesel engines in the last years i thought this mitght be an option.
best regards
I think you need to add a gearbox. Then you can generate the HP at a higher rpm.
The LS is already used in some aircraft
http://members.iquest.net/~aca/photos.htm
http://quietaviation.com/programs/qtpower.html
And the use of Subaru flat 4 petrol engines is very common.
Why the notion of a diesel ?
The LS is already used in some aircraft
http://members.iquest.net/~aca/photos.htm
http://quietaviation.com/programs/qtpower.html
And the use of Subaru flat 4 petrol engines is very common.
Why the notion of a diesel ?
deepb said:
the only subaru boxer diesel i have found is the Subaru EE engine and it has only 147 HP.
why a diesel?
If a diesel stops due to air ingestion....let's see you restart that in a hurry mid-flight.why a diesel?
- more MPG
- more reliable, especially if run at lower RPMs
- thought no redrive needed
- not as flammable (think crash)
I'm not sure how often that might occur, but it has to be considered ? Do petrol engines stall on occasion during some manoeuvres ?
At what altitude or temperature will diesel waxing become a potential problem ?
And petrol engines are generally very reliable. The produce power over a wide operating range too, which surely is a good thing even on an aircraft ?
Diesels no not. And what way would a turbodiesel work in terms of loading to achieve boost pressure to achieve the power/torque you request ?
How common is turbocharging on aircraft on piston engines ?
Not sure on their total weights but the only car diesel engines I can think of that'll give you that sort of power as lightly as possible are the BMW N47s (205bhp/420 or 450 Nm of torque in 123d guise) and the top spec MB OM651 2.1L diesel from the 250Cdi (205bhp, 500NM, peaks early and drops quickly after that).
Of those two the Beemer's your best shot, as it's got an ali block instead of the Merc's cast iron so is much lighter. You'd have to get your hands of the twin turbo version though, which is both going to be expensive and difficult. As mentioned earlier it's in the 123d and now the new 525d.
Of those two the Beemer's your best shot, as it's got an ali block instead of the Merc's cast iron so is much lighter. You'd have to get your hands of the twin turbo version though, which is both going to be expensive and difficult. As mentioned earlier it's in the 123d and now the new 525d.
Fun is all well and good, but i can't see you getting certification for an automotive engine controller (say a BOSCH EDC17 etc) for aeronautical use, and certainly without the help of BOSCH themselves (who will DEFINATELY NOT support you).
As mentioned, your fuel system will have to be excellent, with zero air pick up underall conditions, and possibly (depending on altitude capability) with a fuel heating system to prevent sludging etc
The company i work for has actually just finshed designing a diesel aeroengine, and it was a massive PITA. For anything but remote drone (pilotless) operation is it simply not worth the hassle. (you will get much better MPG by spending the same amount of effort of the L/D ratio optimisation of your airframe. (and remember that often aero engines are running at at/close-to WOT so they don't suffer the normal throttling loses that blight gasoline engines on the ground)
The best, most likely to be certified option will be to use a mecanically injected (non common rail) deisel, but you will require a large capacity to get the BMEP you require in this case (and the limited range of injection mapping (mech advance/pressure cams etc) will not provide very good fuel economy anyway.
And finally, as always, if not many other people are doing it then that means one of two things:
1) wow, you've come up with a great, never thought of before idea
or
2) People, who generally are much smarter than both of us, and have a lot more money to spend, have looked at it, and decided it is not a very good way of doing things
I'll leave it up to you to choose which you would like to believe...... ;-)
As mentioned, your fuel system will have to be excellent, with zero air pick up underall conditions, and possibly (depending on altitude capability) with a fuel heating system to prevent sludging etc
The company i work for has actually just finshed designing a diesel aeroengine, and it was a massive PITA. For anything but remote drone (pilotless) operation is it simply not worth the hassle. (you will get much better MPG by spending the same amount of effort of the L/D ratio optimisation of your airframe. (and remember that often aero engines are running at at/close-to WOT so they don't suffer the normal throttling loses that blight gasoline engines on the ground)
The best, most likely to be certified option will be to use a mecanically injected (non common rail) deisel, but you will require a large capacity to get the BMEP you require in this case (and the limited range of injection mapping (mech advance/pressure cams etc) will not provide very good fuel economy anyway.
And finally, as always, if not many other people are doing it then that means one of two things:
1) wow, you've come up with a great, never thought of before idea
or
2) People, who generally are much smarter than both of us, and have a lot more money to spend, have looked at it, and decided it is not a very good way of doing things
I'll leave it up to you to choose which you would like to believe...... ;-)
I should also add that a small capacity automotive diesel only makes it's claimed peak power at close to sea level. Generally, above approx 1000m the turbochargers boost target is reduced to keep the compressor shaft speed within limits. At 3000m, typically the engine will be making just 60% of it's rated power. (worse than an NA engine which will be at approx 70% of rated power due to the ambient pressure reduction (assuming ISA)
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