GregP
Major
Perhaps we could camouflage a P-40 with a complete skin of Napoletana Pizza. Nobody in his right mind would shoot at it. Add Bacon and the war might have ended early, at least until the wine and / or beer ran out.
P-40 with Griffon engine
- Thread starter spicmart
- Start date
Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules
swampyankee
Chief Master Sergeant
- 4,036
- Jun 25, 2013
I know about both. The P-51 wasn't obsolescent.
I wasn't suggesting it was obsolete, just agreeing with your comment "More useful could have been a Griffon P-51."
GregP
Major
By the time the P-51 with a Merlin engine in it came along, the last gasp of the piston fighters was already underway, at least in Germany, Japan, the U.K., and the U.S.A. . Jets were on the drawing boards and, had the war gone on into 1946, I'm pretty sure that, after the P-51H / Bearcats / Tigercats / Tempests / Sea Hornets / Spitefuls, potential Superbolts, etc., the next set of combat aircraft would have been almost exclusively jets except possibly for the carrier-based Navy, who needed short takeoff more than the land-based services did.
I can't see a Griffon P-51 being needed at all since it would NOT allow the P-51 airframe to be competitive with jets and the P-51H was already (though not in 1943) one of the highest-performance piston fighters in existence. The Griffon would not have been a significant leap in performance with the possible exception of climb rate.
But, perhaps that's just my thinking. Several in here have mentioned a Griffon P-51, but I have seen no evidence to date that tells me it was ever tried or even seriously considered for production. Calculating the theoretical performance of it is not the same as seriously considering it for actual production. On the other hand, I hear that a 2-stage V-12 WAS put into a P-40, but was never proceeded with, and the airframe was converted back into a standard P-40. I have no proof of that, but I at least heard it in a talk given by Don Berlin's son.
The XP-40Qs had very good performance, but not a significant jump better than existing fighters. I think a P-40Q would have rather handily outmaneuvered a P-51D, definitely had better spin characteristics, but it wasn't faster, didn't have quite the range, and likely didn't have as high a service ceiling. In all, not a compelling reason to replace the P-51 in production, even if it WAS a good airplane. They made the correct choice to stick with the P-51 with its Merlin.
I can't see a Griffon P-51 being needed at all since it would NOT allow the P-51 airframe to be competitive with jets and the P-51H was already (though not in 1943) one of the highest-performance piston fighters in existence. The Griffon would not have been a significant leap in performance with the possible exception of climb rate.
But, perhaps that's just my thinking. Several in here have mentioned a Griffon P-51, but I have seen no evidence to date that tells me it was ever tried or even seriously considered for production. Calculating the theoretical performance of it is not the same as seriously considering it for actual production. On the other hand, I hear that a 2-stage V-12 WAS put into a P-40, but was never proceeded with, and the airframe was converted back into a standard P-40. I have no proof of that, but I at least heard it in a talk given by Don Berlin's son.
The XP-40Qs had very good performance, but not a significant jump better than existing fighters. I think a P-40Q would have rather handily outmaneuvered a P-51D, definitely had better spin characteristics, but it wasn't faster, didn't have quite the range, and likely didn't have as high a service ceiling. In all, not a compelling reason to replace the P-51 in production, even if it WAS a good airplane. They made the correct choice to stick with the P-51 with its Merlin.
Last edited:
wuzak
Captain
It wasn't seriously considered for production, but it was proposed by Rolls-Royce at the same time that they were converting a P-51 to Merlin 61 power (the Mustang X). The engine proposed was the Griffon 65.
North American responded that the amount of rework required would not make it practical for production.
A 2 stage V-1710 was put in the P-40 - the P-40Q.
Are you talking of a 2 stage Merlin (which sort of happened with the XP-60D - a P-40D fuselage with laminar flow wings and V-1650-3), or the proposed turbocharged P-40?
Shortround6
Major General
I would note that most accounts of the P-40Q have it armed with four .50 cal guns with "plans" for either six .50s or four 20mm guns in a "production" version which means the production version would have been heavier and had more drag (very common) and if it had stayed at four guns, while equal to the P-51B&C it was 2/3rds the fire power of the D and the H.
Elvis
Chief Master Sergeant
My dad was stationed at Itami in 1946 and they had a P-80 there. When I was a kid, he'd tell me the P-80 pilot would buzz and dive bomb the P-51 flights (he said the 51 pilots were a bit smug, because...you know...they won the war).
Anyway, this would cause a game of "catch-me-if-you-can".....they couldn't.
I have some pics of that plane somewhere around here....and the P-51 that crashed into a building because the kid working on the plane pushed the throttle the wrong way on accident.
My sentiments exactly.GregP said:
Its not that the Q wasn't a good plane, but we already had the P-51 by then. Why do it again?
Had the P-40Q come out in 1940 or even 1941, the history of that plane might be very different and we might not be talking about P-51's now......but that's not what happened.
Elvis
GregP
Major
Hi Wayne,
I'm talking about a standard P-40 with a 2-stage Merlin. Think of a P-40E/F with a longer nose and a longer tail. I heard one was built but have seen nothing that could be shown as proof it ever got built. In the story, after it showed what it could do, the airframe was converted back to a standard P-40 and transferred back to the USAAF. If it were true, perhaps they would have a record of same or at LEAST have recorded the airframe serial number somewhere?
Lacking such proof, I have to conclude that, while of interest to me personally, there is no direct evidence it was ever actually done.
I would have liked to have seen the Griffon P-51. I mean, here's an image of a P-51D with ramjet on the wingtips. There are several more with better detail, but no more with them running.
So, at least there is some evidence it was done. That had to have been a LOUD cockpit about the time the pic was snapped!
I'm talking about a standard P-40 with a 2-stage Merlin. Think of a P-40E/F with a longer nose and a longer tail. I heard one was built but have seen nothing that could be shown as proof it ever got built. In the story, after it showed what it could do, the airframe was converted back to a standard P-40 and transferred back to the USAAF. If it were true, perhaps they would have a record of same or at LEAST have recorded the airframe serial number somewhere?
Lacking such proof, I have to conclude that, while of interest to me personally, there is no direct evidence it was ever actually done.
I would have liked to have seen the Griffon P-51. I mean, here's an image of a P-51D with ramjet on the wingtips. There are several more with better detail, but no more with them running.
So, at least there is some evidence it was done. That had to have been a LOUD cockpit about the time the pic was snapped!
Attachments
Elvis
Chief Master Sergeant
...P-40F...
...its a subtle thing, the missing airscoop. Once you notice it, however, you can't help but see it, and the plane suddenly look SO different.
...its a subtle thing, the missing airscoop. Once you notice it, however, you can't help but see it, and the plane suddenly look SO different.
GregP
Major
It's not just the airscoop. It's also the extended tail. The stab and elevators are in the standard placement, but the fin and rudder are 20 inches farther aft with respect to a P-40E.
Dash119
Senior Airman
One other consideration here with regards to the Mustang and the Griffon;
Several people have posted images of Mustang "Precious Metal" with a Griffon engine. The implication being that there was space from firewall forward, in the mustang, to just swap powerplants. Aside from the weight and balance considerations, and changes to the cowling previously mentioned, most racing Merlins are "Tube" motors. Since this is a race plane, I would assume the Griffon is also a "Tube" motor.
A "Tube" motor replaces the Aftercooler between the Supercharger and the induction trunk, with a simple and direct tube. The cooling of the charge mixture normally accomplished by the Aftercooler is accomplished with ADI fluid sprayed into the manifold at high power settings. While this works at Reno during the course of an Air Race, it is not practical in a fighter aircraft.
So, could you really fit a Griffon as delivered from Rolls Royce, with the standard induction set-up including Aftercooler, into the Mustang airframe without a complete re-design? I'm not so sure the "Precious Metal" example really gets us there...
Several people have posted images of Mustang "Precious Metal" with a Griffon engine. The implication being that there was space from firewall forward, in the mustang, to just swap powerplants. Aside from the weight and balance considerations, and changes to the cowling previously mentioned, most racing Merlins are "Tube" motors. Since this is a race plane, I would assume the Griffon is also a "Tube" motor.
A "Tube" motor replaces the Aftercooler between the Supercharger and the induction trunk, with a simple and direct tube. The cooling of the charge mixture normally accomplished by the Aftercooler is accomplished with ADI fluid sprayed into the manifold at high power settings. While this works at Reno during the course of an Air Race, it is not practical in a fighter aircraft.
So, could you really fit a Griffon as delivered from Rolls Royce, with the standard induction set-up including Aftercooler, into the Mustang airframe without a complete re-design? I'm not so sure the "Precious Metal" example really gets us there...
GregP
Major
You might accomplish this with a pre-cooler. You can calculate the temperature rise based on the pressure ratios, and you either have to add an intercooler, a pre-cooler, or an aftercooler.
I really don't think a pre-cooler would pass muster in a warplane in Europe, especially in late fall / winter /early spring. Might, but there could also be a lot of freezing water/fuel issues between the precooler and the compressor. Maybe not, but ... maybe. At Reno, ADI is sprayed continuously to prevent detonation at highly elevated manifold pressure numbers. At stock MAP and stock power levels, there is the possibility that freezing might NOT be an issue, and a tube motor might work. But the development and testing rather obviously was never done because they went another way and used a cooler on the engine.
Interesting observation, though, that generates some thought. I bet Pete Law would know! If I see him again at the PLanes of Fame, I'll ask him ... post-Covid.
I really don't think a pre-cooler would pass muster in a warplane in Europe, especially in late fall / winter /early spring. Might, but there could also be a lot of freezing water/fuel issues between the precooler and the compressor. Maybe not, but ... maybe. At Reno, ADI is sprayed continuously to prevent detonation at highly elevated manifold pressure numbers. At stock MAP and stock power levels, there is the possibility that freezing might NOT be an issue, and a tube motor might work. But the development and testing rather obviously was never done because they went another way and used a cooler on the engine.
Interesting observation, though, that generates some thought. I bet Pete Law would know! If I see him again at the PLanes of Fame, I'll ask him ... post-Covid.
Dash119
Senior Airman
Post-Covid maybe we will run into each other there...
wuzak
Captain
If I am not mistaken, Precious Metal's engine is a Griffon 57 from a Shackleton and, as such, never had an intercooler.
Regarding the aftercooler, its size and shape put it within the profile of the Griffon, so there is no issue with it there. The size of the inter/aftercooler radiator had to be larger than the Merlin version, as did the coolant radiator. That would require significant alteration to the P-51's radiator duct to make it all fit.
wuzak
Captain
Wasn't that change carried forward to other, later, P-40 variants?
Shortround6
Major General
Not all Fs got the extended fuselage, it was introduced part way through the production run with the P-40F-5 production block. The first 699 P-40Fs had the short fuselage.
Dash119
Senior Airman
Yes, but we are swapping the Griffon into the Mustang to enhance the performance as a fighter... Don't we need a two stage Supercharger to give us the altitude performance? And if we need that Supercharger, more than likely we need the Aftercooler.
The Shackleton was a Maritime Patrol aircraft, and as such I'm not sure high altitude performance was the foremost consideration.
wuzak
Captain
I wasn't suggesting a Griffon/P-51 would use the single stage version, merely pointing out that the Griffon 57 never had an aftercooler to remove.
The Griffon/P-51 would undoubtedly have used the 2 stage Griffon, and that would be fitted with the aftercooler - it was integral with the engine package.
But since the Griffon 57 fitted relatively comfortably in the P-51's engine bay, there should not be any issues with the Griffon 65.
There are some difficulties, though.
The two stage version was also longer and heavier than the single stage. During the war these would have been single rotation, as the dual rotation props were not yet reliable enough for combat use.
That aftercooler and the intercooler (cooling passages around the impellers) require a radiator, which needed to be bigger than the ones on teh Merlin.
The engine coolant radiator also needed to be larger capacity.
These would require modifications to the belly scoop and radiator duct - which was already much larger on the P-51B than it was on the P-51/P-51A.
Stability would probably also be a significant issue.
The P-51 was not as stable once the more powerful Merlin and bigger prop with more blades was installed. Rolls-Royce extended the chord on the fin/rudder of the Mustang X to attempt a solution, and the P-51B/C and D/K got fin fillets to aid stability, but it wasn't until the P-51H that the problem was fixed satisfactorily, with the taller fin and extended fuselage.
Dash119
Senior Airman
Most of the issues you raise are valid and some had already been raised. My specific point was that just because you could shoehorn a racing version of a Griffon into a purpose built airframe conversion, that did not validate the engine swap during wartime.
If you had to have the two stage supercharger, Aftercooler and associated plumbing behind the engine, could you just swap the Griffon for the Merlin? I'm suggesting that the Griffon might have to be placed further forward from the firewall than was necessary on "Precious Metal".
We are hoping to swap the engine and end up with a better weapon of war, without a major re-design or disruption to production. After all, there is a war on....
If you had to have the two stage supercharger, Aftercooler and associated plumbing behind the engine, could you just swap the Griffon for the Merlin? I'm suggesting that the Griffon might have to be placed further forward from the firewall than was necessary on "Precious Metal".
We are hoping to swap the engine and end up with a better weapon of war, without a major re-design or disruption to production. After all, there is a war on....
