XP-40Q-2: test data emerged!

[tomo pauk]

I'm sure that Greg would just love this - I know I do
Mike Williams has posted the flight test data about the XP-40Q-2. The plane made 422 mph, and was able to do ~420mph from 20000-26000 ft. All that on the F-27R engine, up to 3200 rpm and water injection. Mr. Whitney might want to update his book, since he does not states the engine's capabilities with ADI. For climb (= small 'ram'), the power at altitude on 'WER wet' regime was ~1690 HP at 17000 ft, and 1190 HP at 25000 ft.

The test: here; dated April 5th 1944.

So we eagerly await for the XP-40Q-3 tests

 

[Aozora]

Interesting, I've just downloaded. Handling was considered to be much improved over the previous P-40s, with a good rate of roll.

 

[GregP]

Thanks for posting that, Tomo. I've often wondered how it performed and now can read about it. I wonder if we could find a flight report on the XP-72 and the Boeing XF8B ... I always thought those two would have been a great 1 - 2 punch, but really don't have much definitive information to go on except reported top speed. Would be nice to see a V-n diagram and some flight performance data.

 

[drgondog]

I wonder how much degradation of the surface sanding and polishing occurred prior to flight test?

 

[johnbr]

Reading it a sounds like a very good x sport aircraft.Here is 3 way.

 

[GregP]

I doubt the plane was kept in a hangar, but 2 - 3 months of outside with little washing makes even a carefully-prepped finish a bit rough. Too bad we didn't get a test with the standard factory finish. I'd also like to see the number 3 aircraft test it it ever surfaces.

Wouldn't it be nice if performance tests were standardized so the data points and test procedures were similar to one another? They don't publish these things, at least for public consumption, for current service aircraft, sio it will be many years before we know if planes like the F-22 and F-35 have standardized test points even today. They certainly SHOULD, and the test points should be adjusted only when the plane being tested exceeds a previous standard boundary.

 

[tomo pauk]

Lovely 6 view, johnbr

Looking at the climb power graph (small ram) of the V-1710-101, it shows nicely the benefits of the RPM increase, from 3000 ft to 3200. The critical altitude for 'WER wet' (75 in Hg) went from ~9500 ft up to almost 17000 ft - a 7500 ft increase! Cost in power was some 70HP (from 1750HP down to 1680). The crankshaft was still the 6 counterweight type, the future 12 counterweight type was enabling 3200 rpm also in military regime.
Interestingly enough, the critical altitude for the WER for the late models of single stage V-1710s was also at 9500 ft (no ram). One might wonder how fast would be the P-51A, P-39M/N/Q and P-40M/N while operating on 3200 rpm? The critical altitude for the WER should be notably higher, even if we conservatively limit the gain to, say, 5000 ft.
Another interesting thought might be the P-63A and P-38 operating on 3200 rpm. The P-38/40/51 might need a new reduction gear, though, in order to not over-speed the prop.

 

[P-39 Expert]

And the first Allison mechanical two stage (V-1710-93) entered series production in March 1943. P-39s, P-40s and P-51s could have had a two stage engine shortly thereafter.

 

[tomo pauk]

And the first Allison mechanical two stage (V-1710-93) entered series production in March 1943. P-39s, P-40s and P-51s could have had a two stage engine shortly thereafter.

Is there a breakdown of monthly production for the 2-stage V-1710s available?

 

[GregP]

I kind of wonder now how the XP-40Q might have done with a 2-stage Merlin in it. It is a non-starter since they never made one, but the performance might have been sparkling right on up to mid-30k feet.

I am still grateful Tomo posted this and Mike Williams shared it. Wherever Mike found it, I hope there are more flight tests we haven't seen before waiting for us. It would be great to see any previously unpublished flight tests. We're all big fans in here of WWII aviation, and it's tough to get "enough," isn't it?

Kudos to Mr. Williams, who has had a LOT for us to see for a long time.

 

[pbehn]

And the first Allison mechanical two stage (V-1710-93) entered series production in March 1943. P-39s, P-40s and P-51s could have had a two stage engine shortly thereafter.

Good to know, I didn't realise it was so far behind, but a good effort anyway.

 

[tomo pauk]

Good to know, I didn't realise it was so far behind, but a good effort anyway.

Who was so far behind, and behind of what?

 

[pbehn]

Who was so far behind, and behind of what?

The curve tomo, the curve.

 

[tomo pauk]

The curve tomo, the curve.

Perhaps it would've been the best to define the curve, plot the dots representing engines in production of that time, higlight the engines with 2-stage superchargers, also higlight other that are still with 1-stage S/C, conclude how the curve is representative, and then decide who is at, behind and ahead the curve?

 

[pbehn]

Perhaps it would've been the best to define the curve, plot the dots representing engines in production of that time, higlight the engines with 2-stage superchargers, also higlight other that are still with 1-stage S/C, conclude how the curve is representative, and then decide who is at, behind and ahead the curve?

I meant the progress development production curve. In March 1943 the Merlin 60 series had been in production and use for about year, it had been fitted to the P-51 and extensively tested ordered and was being put into production as the P-51B. By March 1943 the P51B was a pretty well sorted aircraft, since many of the issues with the engine airframe and props are at high altitude a lot of testing is requited, because calculations only go so far. being a year behind in the mid 1930s could be made up with some work, a year behind in 1942-43 was an age behind but that was because of decisions made years before.

 

[tomo pauk]

I meant the progress development production curve. In March 1943 the Merlin 60 series had been in production and use for about year, it had been fitted to the P-51 and extensively tested ordered and was being put into production as the P-51B. By March 1943 the P51B was a pretty well sorted aircraft, since many of the issues with the engine airframe and props are at high altitude a lot of testing is requited, because calculations only go so far. being a year behind in the mid 1930s could be made up with some work, a year behind in 1942-43 was an age behind but that was because of decisions made years before.

One series of series does not represent The Curve.
A 2-stage V-1710 is on production by Sping of 1943, so is the 2-stage R-1830 and R-2800, and obviously the Merlin.
Engines in production, but without a 2-stage supercharged version:
R-2600, R-1820. Sabre, Griffon, Hercules or any other non-Merlin British engine. All Japanese engines. All German engines. All Soviet engines, V12 or radial, apart from problematic M-105PD delivered in token quantities.

If we're going to count stages of supercharging and use that metrics on who is at, behind or ahead curve, the 2-stage supercharged V-1710 certainly does not look like it is behind the curve.

 

[pbehn]

One series of series does not represent The Curve.
A 2-stage V-1710 is on production by Sping of 1943, so is the 2-stage R-1830 and R-2800, and obviously the Merlin.
Engines in production, but without a 2-stage supercharged version:
R-2600, R-1820. Sabre, Griffon, Hercules or any other non-Merlin British engine. All Japanese engines. All German engines. All Soviet engines, V12 or radial, apart from problematic M-105PD delivered in token quantities.

If we're going to count stages of supercharging and use that metrics on who is at, behind or ahead curve, the 2-stage supercharged V-1710 certainly does not look like it is behind the curve.

I meant as far as being fitted in the aircraft in p-39s post tomo. By the summer of 1943 the bus had gone for the P39, P40 and P51. For the others the air frame and the engine was fixed it was mainly sorting technical details which had solutions on the test bed.

 

[P-39 Expert]

Is there a breakdown of monthly production for the 2-stage V-1710s available?

All I have is just a chart showing the months in production and the total produced. You could average that for a monthly figure.

 

[pbehn]

All I have is just a chart showing the months in production and the total produced. You could average that for a monthly figure.

Well it would be a start.

 

[Shortround6]

Allison listed 31 different engine models using mechanical two stage superchargers from early experimental versions to post war versions.
Some of these were simply left and right handed versions. 11 of them were never actually built.

Work started on the first one in 1939 or 1940.