Thread: Interesting, Odd or Funny Pics II.

Originally Posted by superquag

Correct me if RRong, but the Allison v12 was essentially a Merlin built by Allison, using 'Merican Mass-production methods, not Pommy-Precision.... eg, any piston would fit any bore of any engine.... nor did we need to worry about keeping said pistons out of *sunlight - on the workbench - during assembley...

But RR didn't tell the Yanks 'Everything'.... Heard about a shaft that Allison kept snapping.... think it was a supercharger drive but don't quote me on that.... Merlins used a cheap softer steel which tolerated the unusual forces..... Allison engineers specified a more modern, better alloy... Think it took them a long while to figure that one out....


* Myth or Fact, ? story is, a piston left on the bench in sunlight for minutes,,, would distort enough to make it impossible to fit... - such was the exactitude of the piston/bore matching. And again, only in its's 'home' bore.

Other interesting Merlin stuff can be had in this book by Len Deighton

Fighter By Len Deighton | Used | 9780586046111 | World of Books

Where he also debunks - with figures - the belief that a Spitfire could out-turn a Me 109. Nope, it 'would' turn tighter... because the German would not violate specifications... the usually more mature Englander regarded them as rules to be modified, like his machine's dihedral. ....

Correct me if RRong,

Ok then J2. Rong is spelt with a W rong. Gettit? My name is not Ron.

Originally Posted by superquag

Correct me if RRong, but the Allison v12 was essentially a Merlin built by Allison,

No. The Allison, as well as the Merlin, copied the general layout of a V12 established by BMW, Renault and Rolls Royce (and later by the American Liberty) during WW1. But apart from this they had little in common except, unsurprisingly, being designed to meet similar specifications, they were about the same size.

The Allison engine performed satisfactorily when introduced, but was not capable of the increase in power that the Merlin saw. In 1936, the Merlin produced 800HP, in 1945 some marks were up to 2,000HP (the most commonly used ones were around 1600HP). Merlins also outperformed the Allison at altitude, largely because of Rolls Royce's supercharger expertise. The exception perhaps was the Allisons fitted to a few aircraft with turbochargers - but inability to supply the high temperature materials needed for the turbines meant these were few in number.

Also completely unrelated to the Allison was the Packard built Merlins, that differed from the UK and Australian ones by using mass production methods and American threads etc. Performance of these was pretty comparable. (At least I am pretty certain that the Australian bult ones were RR spec not Packard)

Pretty sure the last of the Merlin Spitfires had counter rotating props up front to counter the torque reaction on the plane which was especially dangerous on take off.

DL

Originally Posted by 350RRC

Pretty sure the last of the Merlin Spitfires had counter rotating props up front to counter the torque reaction on the plane which was especially dangerous on take off.

DL

Just checking Jeffrey Quill's excellent Book "Spitfire" for that A/C as I had a feeling he mentioned that but i can't locate a reference for that even in the index.

He was a Supermarine Test Pilot for many years & flew them in action during WW2, inc. The Battle of Britain.

Excellent read if you are Spittie inclined. A 300 page paperback published 1983. He died 20 Feb '96. ISBN 0 09937020 4 JQ was a test Pilot at Vickers & Supermarine. The story of the development of all Mks of Spitfire from 1936 up to WW2.


VINTAGE BOOK WAR WW2 PAPERBACK SPITFIRE RAF FIGHTER TEST PILOT QUILL 10 | eBay


DL they eventually went to a four Bladed Prop if that is what you may be thinking of?

Originally Posted by 4bee

Just checking Jeffrey Quill's excellent Book "Spitfire" for that A/C as I had a feeling he mentioned that but i can't locate a reference for that even in the index.

He was a Supermarine Test Pilot for many years & flew them in action during WW2, inc. The Battle of Britain.

Excellent read if you are Spittie inclined. A 300 page paperback published 1983. He died 20 Feb '96. ISBN 0 09937020 4 JQ was a test Pilot at Vickers & Supermarine. The story of the development of all Mks of Spitfire from 1936 up to WW2.


VINTAGE BOOK WAR WW2 PAPERBACK SPITFIRE RAF FIGHTER TEST PILOT QUILL 10 | eBay


DL they eventually went to a four Bladed Prop if that is what you may be thinking of?

Pretty sure I've read it and that's how I know. Just remembered the size of the rudders may have increased to try to deal with the problem as well.

cheers, DL

Originally Posted by 350RRC

Pretty sure I've read it and that's how I know. Just remembered the size of the rudders may have increased to try to deal with the problem as well.

cheers, DL

You may be correct. You Tube shows it in flight but the book doesn't mention it..IL2 Spitfire MK.XIV Contra-rotating propellers. - YouTube

Originally Posted by 4bee

You may be correct. You Tube shows it in flight but the book doesn't mention it..IL2 Spitfire MK.XIV Contra-rotating propellers. - YouTube

Might have been a different book. Pretty sure they increased the size of the rudders before the counter rotating props.

Not a good look cork screwing into the airfield when just trying to get some elevation.

Thinking about it some more........... I'm pretty sure the diameter of the props went up as the Merlin hp rose and there was some other mod that was done as well.

You're mission, 4B, should you decide to accept it is to..............

cheers, DL

Originally Posted by 350RRC

Your mission, 4B, should you decide to accept it is to..............

cheers, DL

Stand-by, awaiting permission from Mrs B, to accept.