Extra Ea-330 pilots: How it stalls?

[Ex-jazz]

Hi

I'm still making slowly a air-race sim/game with Blender 3D build-in game engine (bullet physics).
Mr. Martinsupitis from Lithuania is kindly providing a great help with 2D/3D art & OpenGL shadder coding.

You can see our current public status on vid below:
http://www.youtube.com/watch?v=ZKyOM7rMN-k&hd=1


Since I'm not a aerodynamic engineer or real world pilot of any plane, I would like to hear a real world aerobatic plane pilots descriptions/assumptions  about the Extra Ea-330 airplane stall characteristics.

Thank you for your kind feedback.

[Golfer]

Flown a 200 and 300 but never a 330.  What specifically are you looking for?

[Ex-jazz]

Flown a 200 and 300 but never a 330.  What specifically are you looking for?

Golfer,

Thank you for your interest <S>

Since you have a Extra EA-200 & 300 flight time under your belt, I very much like to hear your opinion about, how the different stalls conditions should model.

Some sort of general guide lines, so to speak.

[Golfer]

I don't know how I can give you useful data because strictly speaking I don't know how to give it if that makes sense.  Stalls were one of the first things I did in each before moving on to various aerobatic figures.

I wasn't really answering because I'd be able to help so much as my information is dated and basic really because as I said while I stalled the airplane it was more to get a feel for flying it at low speeds before moving on to other maneuvers.  Do you have specifics you're looking for and I could see about helping get the information from a better source with more recent experience (and ownership but not of a 330) than mine.

[Ex-jazz]

I'm more interested in general level, than about hard figures.

I understood so, the symmetrical airfoil wings has a easy/smooth stall characteristics but how it's acting during the stall?

A level flight idle power stall? Smooth or sudden wing dropping?

Accerated stall during hard turn? Is there a snap roll?


All these kind information I'm interested, because I would like have a plausible flight model, not 'as real as possible' of certain airplane type.

[MachFly]

I spend some time thinking about this after reading the OP, and I don't think I'd be able to describe how any airplane stalls. I guess that's why one of the first things you do when you get certified in a new (small) airplane is stalls.

Try emailing the instructors at Tutima Academy (Sean D. Tucker's school) at info@tutimaacademy.com, I'm sure they're used to answering such questions and should be able to help you out.

[kamori]

This know from competition R/C Precision and aerobatics flying for 15 years. I competed flying 1/4 Scale(apx. 80" wing span) Extras and The Edge 540's.

Basically heres the difference between the two in a flat stall.

The Edge had a straight leading edge(hence the name) and a fully symmetrical wing(meaning its the same air foil on top and bottom. When you are at level flight and you throttle down to idle you slowly start inputting elevator not to climb but to create a stall. The edge will stall flat it wont drop a wing tip(assuming its a properly balanced plane) The real ones do the same thing. Less effected by engine torque(keep in mind at Idle speed)

The Extra in the same situation will always drop a wing one side will loose lift and drop(in the direction of engine torque most of the time)

Both Planes have symmetrical airfoils.

Remember that C.G.(center of gravity) and Incidence(angle of attack of the wing in relationship to the fuselage) Has extreme effect on stall characteristics.

C.G. Is the balance point on the wing its appx. 1/3 of the wing root back from the leading edge of the wing. The balance point of the wing being Forward of the C.G. means that the plane is Nose heavy and will enter a stall at a faster speed then if the balance point of the wing is Aft of the C.G..

If the Balance point of the wing is Aft of the C.G. then the plane will snap stall faster and be very sensitive to elevator input.  Forward of the C.G. it will be heavy on the elevator.

I spent the better part of a year on an Edge 540 playing with the C.G..and Incidence and engine thrust angle. When it was complete I was able to do level flight at 1/2 throttle and give ONLY Aileron input for a roll and did not need to put in elevator for inverted flight. It drove a competitor friend nuts because my axial rolls were flawless.

Kam

[kamori]

I spend some time thinking about this after reading the OP, and I don't think I'd be able to describe how any airplane stalls. I guess that's why one of the first things you do when you get certified in a new (small) airplane is stalls.

Try emailing the instructors at Tutima Academy (Sean D. Tucker's school) at info@tutimaacademy.com, I'm sure they're used to answering such questions and should be able to help you out.

Basically a stall happens when some or all of a wing looses lift or the angle of attack of the wing is to great for the wing to generate lift by not keeping the high and low pressure difference from the lower and upper part of the wings airfoil or air starts flowing parallel to the leading edge of the wing and starts spilling off toward or off of the wing tips.

Kam

[kamori]

Accerated stall during hard turn? Is there a snap roll?

This is called a High speed stall. The angle of attack is too great for the conditions and Yes it will be a violent "Snap"

Kam

[Seanaldinho]

BTW just wanted to mention how nice the graphics are would like to know more about the game

[Ex-jazz]

Thank you for your valuable feedback.

I try to get all information from any modern aerobatic plane's stalls and then figure out how to code it in to sim.

It could be, I need to do some blatant assumptions, short-cuts or simply skip the whole issue.

Anyhow, I could measure/calculate a each wing lift at the wing's mean chord, to get a 'lift factor difference'  and then got accordingly a roll moment.


@Seanaldinho
Only my made version(2d/3d)  is available for public at this moment:
http://fdm4bge.1g.fi/Files/10001/BGE_AirRace/Demos/BGE_AirRace.zip

http://www.youtube.com/watch?v=vYDfISes8xU
http://www.youtube.com/watch?v=7422m-zrRUo

[kamori]

I'm sure it is one of the toughest things to model. HTC has allot of issue with their stall model, but it is a good attempt. Probably the best one out there.

Good Luck,

Kam

[Ex-jazz]

I'm sure it is one of the toughest things to model. HTC has allot of issue with their stall model, but it is a good attempt. Probably the best one out there.

Good Luck,

Kam

Thanks Kamori,

Yes, the stall modeling is a very mind bending issue with all related dynamics My head is hurting badly  

Anyhow, the AH's stall model is still my target/dream  


(edit)
One issue, which is very much puzzling me, is a pilot fatigue under the G-forces.
In AH we are blacking-out at ~6G's, but in this sim the pilot should be able a pull temporarily a 10G's+ without too much problem.

So, how to model the G-force fatigue?
Perhaps some vision blur, fading colors and loss of external sounds, while sounds of the intense heart beating and breathing grunt sounds are getting higher?

[MachFly]

Basically a stall happens when some or all of a wing looses lift or the angle of attack of the wing is to great for the wing to generate lift by not keeping the high and low pressure difference from the lower and upper part of the wings airfoil or air starts flowing parallel to the leading edge of the wing and starts spilling off toward or off of the wing tips.

Kam

Yeah, I was saying that I can't describe the difference in feeling of the stall in different aircraft. (If that makes seance)