Elvis
1st Sergeant
They could, if there was room, but there isn't any.
It would require so much of a redesign, you might as well design a whole new plane.
It would require so much of a redesign, you might as well design a whole new plane.
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The US was far from awash in 2 stage Allisons in any part of 1943. Production of the V-1710-93 was pretty much a trickle while they sorted out several problems related to using WEP settings. The few P-63s that got the engines were flown under restrictions until the engine passed it's type test in late 1943. First production P-63s using the engine /are built in Oct 1943, the engine passed it's type test after that.If USA is awash with 2-stage supercharged V-1710s in second half of 1943, shove it in P-40s, if installing them on P-51s is too much of hassle.
Now what about a P-51D with one of those suckers? Maybe contra-rotating props for good measure.
You certainly wouldn't be getting a 2 stage Griffon produced in the US in 1942.
If US production of the 2 stage Griffon did go ahead, I suspect that the P-51 would have been the ultimate US recipient. It was, apparently, a lot of extra work to convert to the Griffon compared to the Merlin, but it it was feasible for the P-40 then it would be for the P-51.
Rolls-Royce were advocating a P-51/Griffon 65 in 1942.
The only reason why a Griffon P-51 didn't go too much further than initial analysis is that NAA considered the number of changes required to be excessive.
Yes feasible. Was room, P-39 engine compartment exactly the same size as P-63. The P-63 moved the water tank from behind the engine to the front behind the pilot. Then the auxiliary stage goes in where the water tank was. A/S supercharger was a little heavier than the water tank it replaced, but a four blade propeller would have been needed to absorb the extra horsepower at altitude and balance the slight extra weight aft of the engine. Would have been available from April '43 for use by the AAF. Bell was making 400 P-39s per month at this point in the war.Was this feasible for the P-39?
Is there room for it? What about COG? Could it have been sorted out prior to the P-63 entering production? Who would use it? Who needed it?
Allison made nearly 5000 -93/-117/-109 engines between April '43 and the end of the war in August '45. The "engine" was the same as any contemporary P-38 engine except for the remote reduction gear common to all "E" series engines and the carb being mounted on the auxiliary stage (-93) instead of the engine stage (P-38 engines) where it should have been all along. Only difference was the second stage for the P-38 engines was a turbo and the P-63 engines was mechanical. So the "engine" was in full production. The auxiliary stage mechanical supercharger was just a normal impeller inside a normal diffuser driven by a shaft. It had a hydraulic coupling that helped with automatically controlling the speed and power but this was the only novel feature. Same engine, new auxiliary stage. All that "extended development" (for WEP) was for water injection and pistons/rings that would be used on all Allisons and could have been tested on any contemporary Allison engine. The main reason for the extended development was the P-63 airframe wasn't ready yet. They had engines in April but no P-63 to put it into until October. Bell only completed 28 P-63 airframes the rest of 1943.The US was far from awash in 2 stage Allisons in any part of 1943. Production of the V-1710-93 was pretty much a trickle while they sorted out several problems related to using WEP settings. The few P-63s that got the engines were flown under restrictions until the engine passed it's type test in late 1943. First production P-63s using the engine /are built in Oct 1943, the engine passed it's type test after that.
The P-51D used a V-1650-7. That said the Griffon would have been V-2240.As far as I know, the V-1710 never operated at a high enough power during WWII to require a contra-rotating prop. I don't think it was operationally cleared for over ~1600 HP(?) until the G series after the war. Possibly someone else has better info?
The P-51D used a V-1650-3. That said the Griffon would have been V-2240.
Hey Zipper730,
As far as I know, the V-1710 never operated at a high enough power during WWII to require a contra-rotating prop. I don't think it was operationally cleared for over ~1600 HP(?) until the G series after the war. Possibly someone else has better info?
Contra rotating prop is nice apart from the cost
1 No P-factor
2 No Torque Reaction
3 No Rotating Air
4 No gyroscopic precession.
5 No need to produce counter rotating versions for twin engine aircraft.
Many nasty and dangerous habits we see in aircraft such as ground looping, dropping a wing near the stall or inverting, twin engine aircraft that roll on engine failure.
There is a cost in complexity and maybe a little in weight but its a good idea. I suspect the real reason we didn't see more is that the contra propeller probably shift the CoG forward and required ballast or centre of gravity changes that had not been designed in to original aircraft.
There is a cost in complexity and maybe a little in weight but its a good idea. I suspect the real reason we didn't see more is that the contra propeller probably shift the CoG forward and required ballast or centre of gravity changes that had not been designed in to original aircraft.