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Automotive V8 Engine Conversions for Aircraft

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Automotive V8 Engine Conversions for Aircraft

Old 27th Apr 2019, 23:26
  #21 (permalink)  
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The most disappointing thing about this thread is that they never built a production radial car engine.
But they did build a production radial engine tank - many of the M4 Sherman tanks (49,000 built) had a Continental R975 Whirlwind radial engine. Interesting the M4A6 Sherman had a diesel Caterpillar D200A radial engine. "The Wright RD-1820 was converted to a diesel by Caterpillar Inc as the D-200 and produced 450 hp (340 kW at 2,000 rpm in the M4A6 Sherman". Who would have thought the engine family commonly fitted to the DC3 was also converted to a diesel?

But radials were fitted to a few road vehicles......... Looks like a corn cob in this monstrosity:
https://i.pinimg.com/originals/f8/7c...a0f4cd3604.jpg
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Old 28th Apr 2019, 00:42
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The problem is the duty cycle. Not necessarily for the crank and bearings, but for all the other junk that hangs off the engine. Then you have another fundamental problem. The electrical system for these engines must be “on” all the time unlike a magneto ignition.

The injected Rotax 912 iS requires 7 switches to control it with some hope of failing safely. - Two ECU, Two fuel pumps, two alternators with failover logic dual injectors for each cylinder and dual ignition That might give some of you pause for thought. If conversion was that simple, wouldn’t everyone be doing it?
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Old 28th Apr 2019, 00:43
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The gasoline powered Sherman tanks were nicknamed “Ronsons”.
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Old 28th Apr 2019, 01:26
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Old 28th Apr 2019, 11:03
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Don't let this distract you from the fact that Hector is gonna be running 3 Honda Civic's with spoon engines. On top of that he just came into Harry's and ordered 3 t66 turbo's with NOS's and a Motec System Exhaust.
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Old 28th Apr 2019, 12:07
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Fully sick Bro!
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Old 28th Apr 2019, 16:18
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Originally Posted by Pinky the pilot
I seem to remember that the 'autotug' was touted by GFA to be really something, but suddenly all development ceased and the project stopped with just the one example.

kaz3g; You got any info on just what transpired with that project? And why it has not proceeded?
Folks,
Because, over many years, CAA/CASA stalled the "auto tug" program. Why?? Because they could, despite US experience.
There are thousands of aircraft flying behind "auto" engines, ranging from certified engines (many based on a Mercedes alloy block) through many V-8 powered smaller ag. aircraft in US, and the largest number in Experimental" aircraft.
There are some "interesting" engineering issues, particularly engines based on the Chev. "small block", these are well known and understood.
For those of you pontificating on proposition of potential propeller problems --- what, in heaven's name do you think reduction gears/drives are for??
Tootle pip!!

PS: Alvis radials were extensively used in military vehicles, plenty of boats with Merlin (Meteor) and Allison V-12s.
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Old 29th Apr 2019, 03:49
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"For those of you pontificating on proposition of potential propeller problems --- what, in heaven's name do you think reduction gears/drives are for??"

Of course there are reduction drives on many aircraft engines Leadsled, that goes without saying.

Point is, many look to auto conversions due to the affordability factor, without considering the need for reduction.

A planetary reduction like on a PT6 or double helical reduction like on a Merlin adds cost.

Company I worked for tried it, sunk a lot into it and ultimately failed to achieve a reliable cost effective auto conversion that suited their operation.

Which was a shame, as they put quite some effort into it.
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Old 29th Apr 2019, 07:56
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Question

A planetary reduction like on a PT6 or double helical reduction like on a Merlin
A question for those who may know; Which of the above is the better?
Or is it a case of 6 of one and half a dozen of the other?

Currawong; Any idea what was used in various other engines such as the big radials?

And BTW, what was used in the GTSIOs used in the C404/421 series?
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Old 29th Apr 2019, 08:21
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Currawong,
The only Merlin/Griffon reduction gearboxes I have seen/played with have been straight cut spur gears. A major source of noise.
Tootle pip!!

PS: The pom's ability to cut helical gears, let alone hypoid bevels or double helical gears has always been rather marginal, and in the mid-1930's --- effectively non-existent.
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Old 29th Apr 2019, 09:34
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Originally Posted by LeadSled
Currawong,
PS: The pom's ability to cut helical gears, let alone hypoid bevels or double helical gears has always been rather marginal, and in the mid-1930's --- effectively non-existent.
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Old 29th Apr 2019, 10:04
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Not a proven option yet, but Raptor Aircraft (a brand new kit aircraft designed and being built by an Aussie in the USA) has a 3.0 litre turbo Diesel which is estimated to put out 350 HP.

Raptor Aircraft Home

These VW/ Audi diesels can be truly disruptive - they can run on Jet A1 and their SFC is half that of your air cooled flat sixes.

Fingers crossed they can deliver even half of their promise.
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Old 29th Apr 2019, 10:42
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Originally Posted by lucille
These VW/ Audi diesels can be truly disruptive - they can run on Jet A1 and their SFC is half that of your air cooled flat sixes.
.
No they're not. If you're lucky they'll be at or around 220g/kWh. A IO-550 is easily good for 250g/kWh and probably less when things are leaned properly - maybe closer to 235...
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Old 29th Apr 2019, 20:33
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Originally Posted by Andy_RR
No they're not. If you're lucky they'll be at or around 220g/kWh. A IO-550 is easily good for 250g/kWh and probably less when things are leaned properly - maybe closer to 235...
I stand corrected. OK, not twice. But significantly better. The only figure I can find is for a 2007 BMW diesel of 198 g/KWh. VW have since improved their efficiency. cy. You only have to look at their automotive consumptions to get an intuitive feel.

https://en.m.wikipedia.org/wiki/Brak...el_consumption

Ps.. I tried to look for IO-550 BSFC numbers.. do you have a link?
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Old 30th Apr 2019, 02:35
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What “would be” converters don’t understand is that there are large and quite complex torque waves traveling up and down the crankshaft. These either get reflected, transmitted or damped at the ends. The engine designers take this into consideration but if converters mess with the dynamics then you can get weird and wonderful effects.

Examples: rotax explaining what will happen if the engine is run without a propeller, the Jabiru flywheel attachment saga, various prohibitions on rpm ranges and so on. Even the big radials had issues:

https://www.scribd.com/document/3256...800-Crankshaft
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Old 30th Apr 2019, 06:21
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Andy RR,
I did say marginal.
Could you, perhaps, guess why RR Cars used diffs. imported from USA (GM) from about 1952 ---- sorry for the minor thread drift.
I loved the example illustrated ---- a truly terrible gearbox, base don my experience rebuilding same many moons ago.
Tootle pip!!
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Old 30th Apr 2019, 07:05
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I agree with Leadsled. There are few manufacturers in the world even today who routinely produce AGMA Class 1 gears for aircraft service. It used to be a black art - very, very skilled tradesmen were needed to set up and run the machines - which were Gleason gear hobbing machines, ANCA tool and cutter grinders and CMM’s.

These days there are gear measuring software packages for the CMM’s and they integrate directly with CNC gear hobbers. But to my knowledge, now probably out of date, it is still a black art and the mating gears have to be matched as a set. Each gear is still slightly different and you need to “tune” the hobs and grinders based on the results of your CMM analysis.

As for automotive and industrial gears - easy peasy because they ain’t Class 1. Also be aware that turbines don’t (I think) produce the torque pulses piston engines do.
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Old 30th Apr 2019, 07:52
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Originally Posted by nomorecatering
a 44G drum an hour & quarter $mill @ to buy? Yep I'll take 4!......…...
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Old 30th Apr 2019, 10:23
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Originally Posted by lucille


I stand corrected. OK, not twice. But significantly better. The only figure I can find is for a 2007 BMW diesel of 198 g/KWh. VW have since improved their efficiency. cy. You only have to look at their automotive consumptions to get an intuitive feel.

https://en.m.wikipedia.org/wiki/Brak...el_consumption

Ps.. I tried to look for IO-550 BSFC numbers.. do you have a link?
I googled "IO-550 SFC" and this came up on the first line: https://summitaviationmfg.com/wp-con...-TI_Engine.pdf

It quotes a 0.385 lb/hp.h which is 234g/kW.h although it may have got the best economy and best power figures switched on page 3. These numbers are, however, typical of what I've seen quoted around the traps for many years. As far as BMW diesels doing 198g/kW.h that's a very best-point number and there would be some celebration in the engineering office about it. Some of the old VW PD diesels are sub-200 but it's quite difficult to do and even more difficult to spread out across a useable area. The fuel consumption you see in the day-to-day use of a car is waaaay worse than these numbers, especially on a gasoline engine. If you could cruise at a steady 100km/h at 200g/kWh in a modern car you'd be seeing 3.5-3.8L/100km That's not typical of anything I know of.
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Old 30th Apr 2019, 11:31
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My Austin 7 had the 3speed crash box on a ‘27 magneto ignition engine with updraft Solex

I later fitted a ‘36 coil ignition with 4 speed box fitted with a remote gear stick. The block was ported and polished, polished crank, Twin side draft Solex’s and extractors.

felt like it was fast ☺️

Kaz
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