Lycoming, Continental and Rotax
Jaba:
Agree with some of what you write.Prop strike creates a "torque pulse" (actually a stress wave) that propagates from the propeller through the crankshaft, gets to the other end of the crank and is then reflected back in reverse. This goes on until it dies away or the crank deforms or something else breaks.
I built one of these, that uses the phenomenon of a torsional stress wave, for my engineering masters.
Split-Hopkinson pressure bar - Wikipedia, the free encyclopedia
As for "running over torque" try putting your car in Fifth and let out the clutch and see what happens - you are asking the engine to run in a manner it is not designed to - which is why you have that table in the POH of manifold pressure/rpm combinations - including areas/combiinations to avoid on some engines.
Typhoon, no, its not bull****, marine engines are derated, in some cases there are Four ratings depending on the intended service.
Take a look at the Volvo Penta marine commercial and marine liesure web pages, take the D9 series for example. In pleasure boat form it is rated at 500hp at 2600 rpm. In cat 1 SOLAS form it is rated at 300 hp and 1800 rpm for ultimate reliability in continuous use.
Also look at the D13 which has ratings from 400 to 800 HP!
Diesel inboard - Engine Range : Volvo Penta
D6-370 - Engine range : Volvo Penta
Ahh I don't think so. An engine can only generate so much torque, it can't create more. An elevctric motor can produce more than FLT, simply load it up, the RPM starts falling, and she backs up the Torque V Speed curve quite nicely. We use this to our advantage some times, in fact quite often . Of course what does happen is the current draw starts climbing at a rapid rate, effective but not efficient, but who cares.
Combustion engines do not work that way.
You can apply an instantaneous peak torque by suddenly stopping the propellor, such as a "Prop Strike", this has X amount of torque from the engine plus Y amount from the sudden deceleration of the prop (inertia conversion) and bingo the crank sees a torque spike many times the maximum the engine could ever produce.
That is why you bulk strip em
Combustion engines do not work that way.
You can apply an instantaneous peak torque by suddenly stopping the propellor, such as a "Prop Strike", this has X amount of torque from the engine plus Y amount from the sudden deceleration of the prop (inertia conversion) and bingo the crank sees a torque spike many times the maximum the engine could ever produce.
That is why you bulk strip em
I built one of these, that uses the phenomenon of a torsional stress wave, for my engineering masters.
Split-Hopkinson pressure bar - Wikipedia, the free encyclopedia
As for "running over torque" try putting your car in Fifth and let out the clutch and see what happens - you are asking the engine to run in a manner it is not designed to - which is why you have that table in the POH of manifold pressure/rpm combinations - including areas/combiinations to avoid on some engines.
Typhoon, no, its not bull****, marine engines are derated, in some cases there are Four ratings depending on the intended service.
Take a look at the Volvo Penta marine commercial and marine liesure web pages, take the D9 series for example. In pleasure boat form it is rated at 500hp at 2600 rpm. In cat 1 SOLAS form it is rated at 300 hp and 1800 rpm for ultimate reliability in continuous use.
Also look at the D13 which has ratings from 400 to 800 HP!
Diesel inboard - Engine Range : Volvo Penta
D6-370 - Engine range : Volvo Penta
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Marinised engines are able to produce significantly greater hp per in3 of displacement as compared to land based version of the same engine due the available coolant, oceans full of it !
With Detroit Diesel / MTU I would be more inclined to say the land based engines are dereated marine engines
With Detroit Diesel / MTU I would be more inclined to say the land based engines are dereated marine engines
Marinised engines are able to produce significantly greater hp per in3 of displacement as compared to land based version of the same engine due the available coolant, oceans full of it !
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Marinised engines are able to produce significantly greater hp per in3 of displacement as compared to land based version of the same engine due the available coolant, oceans full of it !
Sorry, I don't agree. The optimum temperature for a water cooled diesel engine is around 90C. All the diesels I have ever operated have easily managed this or lower on a conventional radiator and fan. Sure the sea makes it easy but in this day and age the optimum radiator/fan combo is also not very difficult to build.
Discussion about spark ignition engines is moot in any case. The legacy engines are a dying breed, diesel is the future.
Continental has bought Thielert, and also has their on version of the SMA engine about to be certificated, the TD300.
Austro is producing diesels for Diamond and I haven't seen any bad reports about them.
Engineered Propulsion Systems is certifying its 4.4 lts Flat 8 engine at 400 hp.
There are also any number of engines in the wings, Delta Hawk for one.
Continental has bought Thielert, and also has their on version of the SMA engine about to be certificated, the TD300.
Austro is producing diesels for Diamond and I haven't seen any bad reports about them.
Engineered Propulsion Systems is certifying its 4.4 lts Flat 8 engine at 400 hp.
There are also any number of engines in the wings, Delta Hawk for one.
I'll bet you a litre of AVGAS that there will continue to be more AVGAS or MOGAS engines in the air than diesels (excluding heavy metal aircraft) 10 years from now.
I'll bottle that litre of AVGAS now, in case I have to pay up in 2023.
I'll bottle that litre of AVGAS now, in case I have to pay up in 2023.
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Diesels
Lots of diesels in the pipeline very few certified and even the certified ones (thiealert) having big problems. Deltahawk still trying after more than ten years, still no certification, some 65,000 grand for the experimental version so you can be the guinea pig both financially and bodily. Wanna burn diesel? Get a turbine. The turbine is still the best engine to go flying behind.
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Oracle and Creamie are correct.
When the G100UL paperwork is complete, a 100% drop in replacement will be legally available FLEET wide.
Then the piston petrol burners will be given a new life.
Hang in there
When the G100UL paperwork is complete, a 100% drop in replacement will be legally available FLEET wide.
Then the piston petrol burners will be given a new life.
Hang in there
A south African company have come up with an interesting engine, which seems like a scratch build design, not an automotive conversion. 320 hp and weighs 320 lbs.
Adept Airmotive
Adept Airmotive
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Adept, an engine that i looked at Waterkloof last year is yet another concept, not a certified product, just like the others. The very simple fact is that there is no certified, proven 300hp range diesel in the market place at this time. I hope adept, and a few of the others, get up and provide a real alternative to the huge fleet of IO 540's and520's that are ready for a heavy fuel replacement.
I have seem most of those diesels mentioned here, and a few others over the many years, many running on test stands, ....but.....still waiting fellas.
I was at the Austro factory in Weiner Nuestadt a few weeks ago and they seem like they could kick a goal, but time and millions of dollars will tell.
I saw the prototype c 182 with the SMA fly into Sywell with only 20 hours on it, gutsy, but that engine has at least some history behind it. A bigger 6 cyl version would work but seemingly wont happen.
There is plenty of motivation for a 300 to 350 hp engine, and many in the race, but it is not a simple task and i am still waiting.
Bring it on. About time to shake TCM and Textron up.
HD
I have seem most of those diesels mentioned here, and a few others over the many years, many running on test stands, ....but.....still waiting fellas.
I was at the Austro factory in Weiner Nuestadt a few weeks ago and they seem like they could kick a goal, but time and millions of dollars will tell.
I saw the prototype c 182 with the SMA fly into Sywell with only 20 hours on it, gutsy, but that engine has at least some history behind it. A bigger 6 cyl version would work but seemingly wont happen.
There is plenty of motivation for a 300 to 350 hp engine, and many in the race, but it is not a simple task and i am still waiting.
Bring it on. About time to shake TCM and Textron up.
HD
I don't see the spark ignition engine going away in the foreseeable future. There's a very large already in service fleet of spark ignition engines. The current demand for new, as in OEM engines, is very small by comparison.
Unless there is a very compelling reason for the existing fleet to fit diesel engines there is only ever going to be a small market for these new engines. Too small in most cases to produce them economically. Retrofitting in most cases will be far less cost effective than continuing with the the old engines.
Diamond have fitted Lycomings to their Twin Star.
Unless there is a very compelling reason for the existing fleet to fit diesel engines there is only ever going to be a small market for these new engines. Too small in most cases to produce them economically. Retrofitting in most cases will be far less cost effective than continuing with the the old engines.
Diamond have fitted Lycomings to their Twin Star.
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the new generation of small capacity petrol vehicle engines are now achieving fuel economy figures near enough to diesel engines, especially now that direct injection has been made to work with petrol.
why hasnt this technology made any headway into aircraft engines?
why hasnt this technology made any headway into aircraft engines?
the new generation of small capacity petrol vehicle engines are now achieving fuel economy figures near enough to diesel engines, especially now that direct injection has been made to work with petrol.
I like my Lycoming (Or Continental) once its running all it needs to keep going is a supply of good clean avgas. No electrics needed to manage the engine. I've done some longish over water legs and wouldn't want to be flying behind the likes of a Theilert (or avgas equivalent) when the electrical system goes south and the battery goes flat, or the engine management computers throw their toys out of the cot as has happened on some Theilerts.
Ultralights:
With respect, I think you might need to qualify that statement a little. I'm sure that in an automotive duty cycle you are correct, but in an aviation duty cycle around 55% to 75% continuous power?
As an aside, Monday morning I pick up the Twin turbo V8 diesel replacement for my 18 year old 80 series Landcruiser. I note however that the latest Niccan petrol patrol is about as fuel efficient - by means of turning off a couple of cylinders at cruise - something I don't think you would want to do in an aircraft.
the new generation of small capacity petrol vehicle engines are now achieving fuel economy figures near enough to diesel engines, especially now that direct injection has been made to work with petrol.
As an aside, Monday morning I pick up the Twin turbo V8 diesel replacement for my 18 year old 80 series Landcruiser. I note however that the latest Niccan petrol patrol is about as fuel efficient - by means of turning off a couple of cylinders at cruise - something I don't think you would want to do in an aircraft.
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This thread has gone full circle. The BSFCmin of a "conforming aero engine" one that will operate as nature intended is around 0.385-0.395 and that is pretty hard to beat no matter what you do.
In an aero application requiring all the design parameters we need and want to be met, it is pretty hard to get any better.
you can argue turbines are better....they are, but not down where all the GA machines live. There are compromises and the laws of physics do not change just because we think they should.
In an aero application requiring all the design parameters we need and want to be met, it is pretty hard to get any better.
you can argue turbines are better....they are, but not down where all the GA machines live. There are compromises and the laws of physics do not change just because we think they should.
the new generation of small capacity petrol vehicle engines are now achieving fuel economy figures near enough to diesel engines, especially now that direct injection has been made to work with petrol.
why hasnt this technology made any headway into aircraft engines?
why hasnt this technology made any headway into aircraft engines?
My 6.0 L V8 Commodore SS uses 99.9+ L/100 km on "take-off"
, but drops back to 4 cylinders when cruising on a flat road and uses 8 L/100 km at 100 km/hr. Don't know what my wife's 2.0 L Corolla uses on TO, but it also uses 8 L/100 km at 100 km/hr!
Kinda cool when I think my 1976 Torana 4.3 L V8 used about 25 L/100 km, but I don't think I want computers running my aeroplane engine!
Dr
Last edited by ForkTailedDrKiller; 16th Aug 2013 at 01:01.