posted 08-05- 09:07 AM               

While working on the D.520 FM, I encountered this problem: with my current work version (haven't tried with the released version) it is possible to perform strong pitch oscilliations (say 0° to 15° pitch) with no joystick input. Set the D.520 steady at low altitude, at about 160 kph. Reduce throttle progressively while trying to keep the same altitude, flaps down. As speeds decreases, it is impossible to maintain a constant pitched up attitude because the plane will start oscilliating on the pitch axis.

By going into external view, I see that the elevator itself is oscilliating, pitching neutral, then full up, then neutral, etc. At the same time my joystick does not move at all, it is fully pulled back!!!

posted 08-06- 01:33 PM               

The occilation is a combined result of the CofG and the wings stalling. The nose will drop, gain airspeeds, and rise again only to stall at the high AoA...

To solve this in the D.520, add weight to the front of the aircraft to shift the CofG forward.

posted 08-06- 02:30 PM               

Typically you don't descend at a high AOA, but "flare out" just before touchdown to allow the plane to stall and settle on the runway.

The oscillations could be due to the elevators being bounced in and out of the slipstream. The air htting the elevators might allow them to move if you have too much deadband set for your stick.

There are several other reasons the 109 and 520 may exhibit this, but the F4U doesn't. The corsair is much heavier and has the gull wing shape, flaps are different, and max flap angle is different. Hstabs are at a different height in relation to the wings also.

posted 08-06- 03:19 PM               

I mean, elevator angle is supposed to be controlled by only two things: stick input, and speed (that's the role of the airAdvantage property, to simulate heavier controls at high speeds).

But my problems occur at low speed, with a neutral airAdvantage value (1.0). What can explain the elevator going full pitch to neutral then back while the joystick was fully pulled back (and throttle steady at 40%)?

So, as I understand it, SDOE simulates what a pilot could do: at high AOAs, release the stick a bit to prevent stall.

I don't understand why... I am supposed to be at the controls, not the program. I am fully prepared to face the consequences my poor flying skills... Why does the program prevent me from stalling when I should?

Maybe the patch guys could have a look at this. For me this is clearly a bug, not a feature (or a last-minute-fix feature, like the hard-coded engine DM).

posted 08-06- 03:39 PM               

To see this:

• take off in a Bf.109E
  
• fly level

• go in external view (F2) the press numpad 5 two times (so that the camera is totally attached to the plane). Rotate the camera so that you are immediately behind the plane's tail.
  
• do a very sharp turn: yank the plane 80°, and pull stick full back. The plane rotates very quickly, attaining a high AOA.
  
• then you see the elevators control surfaces going into neutral position on their own , the program is releasing the stick, even if you are not!
  
• AOA is reduced, turn rate is reduced and the plane does not stall
  

posted 08-06- 04:38 PM               

Notice how we all immediately went to the "tech approach"... and completely ignored the obvious possibilities...

We can be such nit-wits sometimes...

posted 08-13- 07:30 AM               

quote:

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Originally posted by Da Jug head:
Pachy, change the AOA- there is the possibility that you're trying to hold it at an attitude where elevator blanking occurs due to full flaps being applied.

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Do you have any details from the message? I'd like to know how they made this work. What if you have a T-tail?

posted 08-13- 10:59 AM               

Found out from Pachy the problem wa a game setting.

Maury, all I know was MH told me elevator blanking can occur. Don't know any other details.

Sorry