WELLS! HELP!

[flakbait]

Apparently since this new FM in 1.04p2, people are doubting the inverted flight qualities of aircraft. Since you're the expert, mind working up some stuff for inverted flight? Preferably REALLY mind-bending in the math, so we can give Pyro a migrain  

Thanks

Flakbait
Delta 6's Flight School
"My art is the wings of an aircraft through the skies, my music the deep hum of a prop as it slices the air, my thrill the thunder of guns tearing asunder an enemy plane."
Flakbait
19 September 2000

[hblair]

 

Originally posted by flakbait:
Preferably REALLY mind-bending in the math, so we can give Pyro a migrain  

LOL, poor 'ol pyro.
 

[Badboy]

Hi flakbait

   

Originally posted by flakbait:
Apparently since this new FM in 1.04p2, people are doubting the inverted flight qualities of aircraft. Since you're the expert, mind working up some stuff for inverted flight? Preferably REALLY mind-bending in the math, so we can give Pyro a migrain    

I'm not sure what the arguments are for and against, but I had a diagram handy, so I hope Wells won't mind if I make a few observations.

You don't really need much math to figure it out though. The reason this point is a tad obscure is that lift curves are often incomplete when shown in books. Most diagrams only show the lift for positive AoA values, but the complete lift curve is typically more like the one shown below.

   

You will notice that by commanding negative AoA (forward stick) you can indeed generate very significant negative g. You will notice that the wing won't produce as much lift that way, and stalls more suddenly and at a lower AoA, but is still clearly capable of performing maneuvers like the outside loop.

What normally prevented such maneuvers (if we ignore engine issues) had far more to do with pilot physiological limits than lift limits. Quite bluntly, sane pilots just don't do it!

If such maneuvers are found to be effective in AH, my suggestion would be to leave the flight model alone, because it is probably fine, (but I've never checked) what might be a more equitable solution perhaps, is adjustment of the pilot physiology model. One way to model the extreme discomfort felt by pilots during negative g and thus discourage the use of such maneuvers, would be to increase the delay on redout recovery, for example.

Hope that helps    


Badboy...

PS
I don't care which way up their aircraft is when I kill them    
 


[This message has been edited by Badboy (edited 09-21-2000).]

[wells]

hehe

I haven't played with inverted flight much since beta, but I recall the 109 didn't fly very well inverted.  While lift (right-side up) can be figured from stall speeds that are given in pilot manuals, lift from negative angles of attack is more difficult to get.  You need some kind of CFD airfoil analysis tool that will support boundary layer separation for stalls that runs very expensive (over 5 grand, I think).  Then you need the airfoil data itself with about 50 coordinate points that define the airfoils shape.  For sure, these planes can't lift as well inverted and without the data, the best one can do, I would think, would be to limit the down elevator deflection so as not to be able to exceed the negative G-limit.