The P-47N right now suffers from adverse stall roll, pulling just a little bit above the critical AoA and the entire plane immediately starts to roll like crazy, which is so extreme that no other prop plane’s stall roll could match. The stall characteristic is utterly different from the P-47D series. As you can see in the video:
It turns out that one important factor in the FM file related to the stall characteristic is mistyped. The factor ‘AfterCritMaxDistanceAngle’ is assigned to be only 3, which is 12.7 times lower than other P-47’s 38, which gives the plane extremely abrupt stall.
P-47N:
P-47D:
In case you don’t know how the value affect the plane’s stall characteristic, the value affects the process of the stall where the lift coefficient turns from linear to inverse parabolic. A small value will make the stall happens in a very small interval of AoA. Here’s a diagram comparing in MaxDistanceAngle =30(Blue) vs 38(Red) from the SAS forum of the IL-2 1946, as this value is inherited from the IL-2 1946 and I don’t have a developer’s tool to output the a polar for WarThunder.
Most prop planes in the game has the value > 30. Some plane gets very low value to simulate its poor stall characteristic, such as the Ki-44 got the value of 18 and it already made an abrupt stall. The P-47N’s AfterCritMaxDistanceAngle =3 basically render the plane useless, as it will experience the most abrupt stall in the entire game.
This is incorrect as the P-47N should have a similar stall characteristic just like previous P-47D series, as it was stated in the report FLIGHT TESTS OF THE P-47N AIRPLANE AAF NO. 44-88406:
Which is very gentle and with little tendency to drop left, so it couldn’t be strong rolling moment as showing in WarThunder:
P-47 stalling
So yes, the stall characteristic of the P-47N should be fixed, the Typo in the FM file should be corrected from 3 to about 30-38 in sure the plane functions like normal.
Another bug is that despite having a slotted flaps with over 50% of the span, the P-47N with full flaps only gets a maximum lift coefficient of 1.65, which only gained 0.1 from no flap position, which is utterly wrong considering the P-47D has the CLmax of 1.85 with full flaps with a gain of 0.4 from deploying the flap, so that’s another bug to be fixed.
Of course, the minimum fuel load of 50min, is a long mistake that should be discussed. The P-47N manual listed its normal gross weight of 13,854lbs, which is similar to that of P-47D:
The SAC file gives the designed weight 13,823lbs. The main and aux tank capacity of the P-47N is unchanged 370 gal, same to the P-47D. The wing tanks are optional and can be flew in empty, as we see in cases of J2M and F4U, both types of aircraft have wing tanks for extended mission, but not often used, and that portion shouldn’t be counted in calculating the minimum fuel load.
P-47N to be fixed:
- Stall characteristic
- Flap lift polar
- Minimum fuel load.
Hope it can be a useful thread to discuss the FM problem of the game.
