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Take that, you radial engine perverts !!!!!

J. Armstrong

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The Allison was actually basically an excellent engine, the only thing that kept it in the Merlins' shadow was, as you note, the lack of a two stage supercharger that would fit in the Mustang. Two stage Allisons were used i the P63 and P82 twin Mustang and performed well at altitude.
The Allison is a much simpler and easier to maintain than a Merlin, and in many respects is stronger. Two lesser negatives were the lack of a high pressure cooling system and a slightly under-refined combustion chamber. MUCH better valve/cam setup than the Merlin.
That's a pretty P40 !
 

ExCdnSoldierInTx

Don’t California my Texas!
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The DBs have only been rebuildable in recent times. Rolls rebuilt one many years ago for one of the English Mes and told them don't ever trash the crankshaft because they couldn't rebuild it ( don't know why ). Apparently the specialty shops like Vintage V12s have "relearned" the DBs.
That fuel injection pump is a real amazing piece of work. Conversely, all but the very last DBs had an inherent assymetric cooling issue and as a consequence had to run a lower compression ratio on one of the cylinder blocks. Weird !
I've always questioned the issue with the Jumo powered Mes. The Jumo is virtually. the same weight as the DB, makes me think the real issue may have been a change in cg due to mounting difference ? Seems like a pretty elementary design mistake if that is the case.
I think part of it might have been a torque issue as well. The JuMo used was the one used in the 111’s, Ju-88’s, etc. a bomber engine, so it had the punch to turn a big paddle prop at a slower RPM, maybe?
Maybe yes, the mounting points might have been in different locations as well?
Either way, it wasn’t a match with the 109, and a lot of very experienced Brits, Canucks, and Americans with multiple hundreds of combat hours and many air victories trashed those JuMo powered 109s on the ground.
 

Slaughter

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We got invited next Friday to a night check-run of one of Vintage V-12's Rolls-Royce Griffon engines.

https://vintagev12s.com/

The last test run on one of their rebuilds is done at night since you can SEE stuff that gets missed during a daylight run. We will be taking videos! - pic of a Merlin from their website: 1684085187309.png
 

J. Armstrong

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We got invited next Friday to a night check-run of one of Vintage V-12's Rolls-Royce Griffon engines.

https://vintagev12s.com/

The last test run on one of their rebuilds is done at night since you can SEE stuff that gets missed during a daylight run. We will be taking videos! - pic of a Merlin from their website: View attachment 298321
Fantastic !!!! I envy you (y)
Please keep us posted - thank you !
 

STG_58_guy

I'm not this cute IRL
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From the looks of the propeller, the engines rotated in the same directions. I know that induces some uncomfortable characteristics while flying and maneuvering. IIRC, the Brits seemed to not worry about counter revolving engines, most likely a wartime contingency. I believe all of the U.S. multi engines had them. But I could be wrong.
When a prop turns it's because the plane applies torque to the prop. Newton tells us the prop applies a torque to the plane in response. If the props turn opposite directions the torque on the plane cancels out. If they turn the same direction, the torque on the plane is the sum of the two.

US planes did both. I think the P-38 started out one way and switched. It is expensive to have nonsymetrical parts. Planes with one engine or noncounterrotating props roll and turn one direction much more quickly than the other. There are also weird gyroscope forces that cancel out.

Counterrotating and contra-rotating are not the same and their misuse makes it impossible to search for which planes were counterrotating :confused: Contra-rotating mean two props on one axis turning opposite directions. Counterrotating is two props each on their own axis turning opposite directions.
 
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C-ya

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Some Typhoon action and Spitfire at the end. This video leads into the one below.



Some Allison action along with some Typhoon flying and touch and go. 80th anniversary of the dam buster raid.



Avro Lancaster, Spitfire, Hawker Hurricane.

 

EinheitElf

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Here are a couple youtube vids of the HE-111 That was powered by 2x rolls royce msrlins because 2 DBs were not functionally available.
I saw this plane numerous times at shows,went inside it,have pics of interior and me with it. Was great. It was Francos transport far as i know.
I forgave the engine fopaw and just enjoyed seeing it fly. Sitting in that glazed noae made you feel very exposed but great visibility.
I donated to help with getting the 2 DBs rebuilt so it would be right... then it crashed in 2003. Horrible loss all around, dont remember the cause.


And

 

alphadog58

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Here are a couple youtube vids of the HE-111 That was powered by 2x rolls royce msrlins because 2 DBs were not functionally available.
I saw this plane numerous times at shows,went inside it,have pics of interior and me with it. Was great. It was Francos transport far as i know.
I forgave the engine fopaw and just enjoyed seeing it fly. Sitting in that glazed noae made you feel very exposed but great visibility.
I donated to help with getting the 2 DBs rebuilt so it would be right... then it crashed in 2003. Horrible loss all around, dont remember the cause.


And

Went aboard that bird when she showed up at an airshow in Groton, CT.
Larry
 
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