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flybywiresim / aircraft

The A32NX & A380X Project are community driven open source projects to create free Airbus aircraft in Microsoft Flight Simulator that are as close to reality as possible.
https://flybywiresim.com
GNU General Public License v3.0
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Elevator efficiency #6557

Open andrejetcat opened 2 years ago

andrejetcat commented 2 years ago

Aircraft Version

Experimental

Build info

{
  "built": "2022-01-17T08:02:53+00:00",
  "ref": "experimental",
  "sha": "618cd97ca856495286ada3fc04cc3dd69b881601",
  "actor": "aguther",
  "event_name": "manual"
}

Describe the bug

I know, no support for the Experimental version but I think its a general "problem"

Today I do some practice-approaches @ EDDK, FOB 3800kg, T/O CG 25,8%.

after touching down, while decel I pull the stick back (because I only want to test that) to give full elevator up input and the plane starts to rotate again at about ~70-80 kts. Thats in my mind very unusual and not realistic at all. I do not have numbers to proof it exactly, but I don´t think you can rotate the A320 at about 70-80 kts. To my mind, thats to much Elevator efficiency in the Sim.

The picture do not show much, but i shows the pitch-up attitude at low speed while roll-out.

pitch

Expected behavior

realistic rudder efficiency

Steps to reproduce

  1. make a takoff or landing roll
  2. give full pitch up input at low speeds
  3. watch Elevator efficiency and attitude chance

References (optional)

No response

Additional info (optional)

No response

Discord Username (optional)

No response

hotshotp commented 2 years ago

@aguther

donstim commented 2 years ago

Thank you for advising us of this issue. We were actually aware that this issue exists and that it may be due to too high an elevator efficiency within MSFS. After investigating this issue, we have decided not to take any action on it at this time for the following reasons:

  1. There is no data showing at exactly what speed the airplane would be capable of pitching up while on the runway. The best that we could surmise was that the airplane may be able to begin pitching up at light weights at about 10-12 knots higher speed than on the A32NX.
  2. This is very large abuse of the procedures for rotating the airplane for takeoff. Even so, the airplane will not lift off at this speed. The minimum lift off speed is fairly close to the A320neo minimum unstick speed.
  3. The current airplane's flight control system was laboriously tuned using the current elevator efficiency value. Changing this value to accommodate an abnormal application of the controls would upset this tuning and require many hours of reprogramming/testing/tuning.