F4U-1D Corsair – Flight Model & Systems Observations

[tityus]

Howdy,

I’d like to share a few technical observations that might help bring the current version even closer to the documented behavior of the real aircraft:

1. Flight Model – Historical Flight Characteristics
1.1 Stall Behavior
The F4U-1D is known to stall the left wing first, resulting in an abrupt roll to the left, sometimes exceeding 100 degrees. This occurs in both power-off and power-on stalls, with the latter being more abrupt. (Starboard stall strip attenuates but didn't impede)
At low speeds/approach attitude, the stall typically occurs without any aerodynamic warning (buffeting).
Recovery is simple, if sufficient altitude is available.
This behavior is documented in NACA evaluations and pilot training materials. It appears to not be already reflected in the flight model. It may be worth adjusting the stall onset characteristics, aileron effectiveness near stall, and control feel to replicate this behavior more accurately.

1.2 Yaw Response and Stability
In testing, I noticed that a brief rudder input leads to sustained, underdamped yaw oscillations, with a noticeable nose drop following the input.

The real Corsair had strong directional stability, owing to its large vertical stabilizer and long tail moment arm. A brief rudder kick should result in a lightly damped yaw response, typically settling after one or two cycles.

The current behavior suggests insufficient yaw damping, potentially due to low Cn_beta, Cn_r, or underrepresentation of rudder and tail effectiveness. The resulting yaw "hunting" and pitch coupling aren't consistent with known handling characteristics from flight test data.

1.3 Trim Stability
The F4U-1D should be relatively easy to trim for level flight, particularly in cruise. It was considered stable in pitch and directionally well-behaved once properly trimmed. Look, mom, no hands!

2. Equipment – Armament Systems
2.1 Rocket Arming – Mark 3 Distributor Box
One detail worth noting about the ROCKET ARMING switch is that it governs fusing mode, not rocket enablement, as the SAFE/ARM labels might suggest.

ARM: Rockets are fused to detonate on impact.
SAFE: A short delay fuse is used, allowing the rocket to penetrate the target a bit (e.g., buildings, ships, vehicles) before detonation.

This function is documented in the POH and plays a significant tactical role. It appears not to be modelled, but it would be a great addition for authenticity in ground-attack scenarios.

Thanks again to the team for your work in bringing the Corsair to life in the sim.

 

Edited Saturday at 09:36 PM by tityus

[-Rudel-]

25 minutes ago, tityus said:

2. Equipment – Armament Systems
2.1 Rocket Arming – Mark 3 Distributor Box
One detail worth noting about the ROCKET ARMING switch is that it governs fusing mode, not rocket enablement, as the SAFE/ARM labels might suggest.

ARM: Rockets are fused to detonate on impact.
SAFE: A short delay fuse is used, allowing the rocket to penetrate the target a bit (e.g., buildings, ships, vehicles) before detonation.

This function is documented in the POH and plays a significant tactical role. It appears not to be modelled, but it would be a great addition for authenticity in ground-attack scenarios.

Thanks again to the team for your work in bringing the Corsair to life in the sim.

A lot of issues have been looked into already.  However, we'll take a look at the HVAR fusing

null

[Saxman]

2 hours ago, tityus said:

At low speeds/approach attitude, the stall typically occurs without any aerodynamic warning (buffeting).

This is contradicted by Vought's operations manual:

There's aerodynamic warning during carrier approach in the form of increasing heaviness in the left wing and a corresponding necessity for right rudder input.

[Hayrake YE-ZB]

5 hours ago, tityus said:

Howdy,

I’d like to share a few technical observations that might help bring the current version even closer to the documented behavior of the real aircraft:

1. Flight Model – Historical Flight Characteristics
1.1 Stall Behavior
The F4U-1D is known to stall the left wing first, resulting in an abrupt roll to the left, sometimes exceeding 100 degrees. This occurs in both power-off and power-on stalls, with the latter being more abrupt. (Starboard stall strip attenuates but didn't impede)
At low speeds/approach attitude, the stall typically occurs without any aerodynamic warning (buffeting).
Recovery is simple, if sufficient altitude is available.
This behavior is documented in NACA evaluations and pilot training materials. It appears to not be already reflected in the flight model. It may be worth adjusting the stall onset characteristics, aileron effectiveness near stall, and control feel to replicate this behavior more accurately.

1.2 Yaw Response and Stability
In testing, I noticed that a brief rudder input leads to sustained, underdamped yaw oscillations, with a noticeable nose drop following the input.

The real Corsair had strong directional stability, owing to its large vertical stabilizer and long tail moment arm. A brief rudder kick should result in a lightly damped yaw response, typically settling after one or two cycles.

The current behavior suggests insufficient yaw damping, potentially due to low Cn_beta, Cn_r, or underrepresentation of rudder and tail effectiveness. The resulting yaw "hunting" and pitch coupling aren't consistent with known handling characteristics from flight test data.

1.3 Trim Stability
The F4U-1D should be relatively easy to trim for level flight, particularly in cruise. It was considered stable in pitch and directionally well-behaved once properly trimmed. Look, mom, no hands!

 

1.1 Our simulated version has the famous stall strip on the right wing that was added to offset the wing drop.

1.2 The real Corsair also has a large, destabilizing fuselage moment ahead of the CG.

1.3 The simulated F4U seems easy to trim and is stable even when mom is not looking!

[BRONYA]

Any rich dude out there who can hook the production team up with an F4U experience?各位有钱的朋友们，谁能帮制作团队安排一次 F4U 的体验？

 

 

[tityus]

18 hours ago, Saxman said:

This is contradicted by Vought's operations manual:

There's aerodynamic warning during carrier approach in the form of increasing heaviness in the left wing and a corresponding necessity for right rudder input.

I believe this excerpt you posted is from the 1945 manual, when a larger Starboard stall strip was added.  I may be "recalling it" wrong, but first versions were closer to what I described.  
Anyway, buffeting is good to warn players, the Mark 3 Distributor Box will be looked into and the last issue is "at the stall, to roll left" the heaviness of the left wing Saxman illustrates the behavior.

I'll mark this thread as solved. Thanks

[Saxman]

2 hours ago, tityus said:

I believe this excerpt you posted is from the 1945 manual, when a larger Starboard stall strip was added.  I may be "recalling it" wrong, but first versions were closer to what I described.  
Anyway, buffeting is good to warn players, the Mark 3 Distributor Box will be looked into and the last issue is "at the stall, to roll left" the heaviness of the left wing Saxman illustrates the behavior.

I'll mark this thread as solved. Thanks

From the 1942 version:

Warning is less marked, not non-existent.

Is the stall light actually working?