My initial impressions from flying the new P-39s.
I’ll begin with the P-39Q as it will be the more popular of the two new editions.
Let me begin by saying that I find to speed curve to be odd. Typically, for the P-39Q using WEP, critical altitude (AKA Full Throttle Height) should occur at 9,700 feet. The current release offers a critical altitude right around 12,000 feet. This conforms to the MIL power critical altitude rather than WEP. Not a big issue, but it does move the P-39Q’s sweet spot up and generally out of the normal combat altitudes found in Aces High.
All performance numbers reflect not taking the under-wing gun pods.
When at critical altitude (12K), the P-39Q can attain 382 mph. I was expecting about 388 mph at 9,700 feet, but the best I could get was 374 mph at that height. Speed at 10k is 375 mph, which is competitive with most fighters, and very good for a middle 1942 vintage aircraft. While I didn’t test with gun pods installed, I expect about a 6 mph loss associated with the increased drag.
Max speed at sea level was measured at 329 mph.
Acceleration is good for a mid war fighter. Measured from 150 mph to 250 mph at sea level, the P-39Q accelerates faster than the P-51B and is only slightly inferior to the P-51D and Yak-9U over this speed range. While not stunning by any standard, acceleration is pretty good and close to what I had previously calculated.
Climb is also quite respectable. Beginning from a stop on a runway, the P-39Q easily beats the P-51D and F4U-1A to 5,000 feet. It lags behind the Yak-9U by about 300 feet (the Yak passes 5,000 ft just as the P-39Q reaches 4,700 ft).
Dive testing was done on both types. Air spawning at 30,000 feet, the gear was pulled up and the engine was started. Nosing over at full power, the P-39s were both dived to max speed. Both attained speeds of at least 595 mph. Buffeting began at approximately Mach 0.75 and full lock-up at occurred at Mach 0.80, which required elevator trimming to pull out of the dive. These numbers are virtually identical to the F4Us. Unlike the Corsairs, there is a risk of shredding the ailerons as you approach 600 mph. This happened during one of four test dives.
Now we get into more subjective performance characteristics.
Turn radius was measured in terms of time required to complete an average circle. I established a constant left-hand turn at 500 feet ASL. I then recorded the total time over three consecutive turns while monitoring air speed via E6B.
The average time for a clean airframe (no flaps) was 17.55 seconds at 154 mph.
Flown against an F4U-1 in a constant left lufbery, the P-39Q quickly overtakes the Corsair. One notch of flaps by both tightens up the circle and the F4U gains parity. Two notches by both and the F4U begins to close on the P-39. Should the P-39 add more flaps, little is gained. It cannot hope to sustain a flaps-out turn fight with the F4U. Like some other fighters, the P-39’s flaps are not designed for maneuver combat. They generate considerable drag without the huge lift component that the F4U flaps provide. I do not recommend using more than 1 or 2 notches of flaps dogfighting in the P-39s. This is even more critical for the P-39D, which has 270 hp less than the P-39Q. There is simply not enough power to overcome the huge drag associated with full flaps. Avoid using a lot of flaps to furball as the gains are more than offset by the losses.
Adding to this issue is a tendency for the P-39s to dip the inside wing almost immediately beyond entering stall buffet. Roll stability at high AoA with flaps out is marginal. It is possible to get into a violent spin that requires several thousand feet to recover from.
Another factor is highly sensitive elevators. You must be smooth with elevator inputs as they are very powerful or you will experience pilot induced nose bounce.
Overall handling is not unusual or inferior. In some regimes, it is simply different from what the average pilot is used to. Different isn’t necessarily bad, nor is a bit of instability, if you can harness it to and use it to enhance maneuverability. It takes stick time to do that. For most players, the P-39s will thought of as being somewhat tricky to fly at the limits.
Outward vision is generally good, being outstanding over the nose. Rear vision is marginal with the roll-over structure creating a tunnel-like view to the rear.
Ground handling is among the best, and landing is very easy without any drama whatsoever. There is a bug in auto-takeoff that causes the rudder to oscillate back and forth, inducing snaking on the takeoff run. Manually taking off is easy, but requires considerable rudder to offset torque.
Sitting in the runway, apply full power and the P-39Q accelerates smartly, getting airborne after a very short run.
Many will find the guns a bit disconcerting as the mixed battery offers substantially varied ballistics. The best gun package is probably the Hispano set-up in the P-39D. Adding the under-wing guns to the P-39Q adds considerable firepower. However, the performance trade-off will cause some folks to go with the less capable paired MGs/37mm combination.
One issue with the P-39 is that the guns shoot higher than the gunsight. You quickly learn to compensate, but this needs to be corrected.
Taken as a whole, the P-39Q will find a following, especially in the mid war arena where it is very competitive. In the late war arenas, it will have a tougher time. Nonetheless, it will be competitive enough to entice players to fly it.
My regards,
Widewing
