Canard Flight Modeling

[N2056]

I am hoping someone can give me some advice on how to set up the flight model for my Quickie. My guess is that FSX has no way to account for the lift generated by the canard wing. Am I right?

 

[JohnC]

Yes and no. Shoot me a pm and I can get into a more detailed discussion if you like. But in general.

- There are no AoA based tables to account for horizontal stab lift contribution, but there is a general setting which can be adjust against Mach number.

- While more aerodynamically efficient, canards can be less stable in normal flight pitching.

- The downwash generated by the canard on the main wing will typically mean that it stalls first in an unaccelerated condition. (Opposed to a rear horizontal stab, which usually stalls ~10 deg past the main wing for the same reason). This results in a significant nose down moment because the CoG must be between the canard and main wing.

Hope this is helpful

Kind Regards,
John

 

[Anneke]

Is it not possible to study the characteristics of the AlphaSim Rutan 61 Long-EZ?

 

[N2056]

It is, and I will...but I thought I also ought to poll the masses

 

[warchild]

a trick you can use is to simply move the elevators to in front of the wing along with the horizontal tail.. it's a little tricky and with as much mucos as there is between my ears today, i'm not ready to go into a deep detail about it, but it can be done..
Pam

 

[N2056]

Hey Pam, sorry you are apparently a bit "under the weather". :isadizzy:

That is one thing I have considered. I might experiment with it, but I am also not wanting to spend a huge amount of time on this as it's going to be freeware. I'm getting close to something that might work...

Get well soon!

 

[Marvin Carter]

I think there will be some animation problems with the canard also, There is with the Alpha sim long ez. It is reversed?

 

[N2056]

The animation currently is correct. So is the one on the Long EZ
Think about it...on a canard if I want the nose to rise the elevator must move down to impart that force.

 

[fliger747]

As mentioned earlier, FS does not directly model the action of an elevator, but instead applies a lift and a pitch factor to the wing. An example, go down the runway in a taildragger and at some point before it will fly off the runway three point, pull back on the stick and the mains will come off the ground, which is impossible in real life as the elevator can only increase the AOA by dropping the tail, which is impossible in a three point configuration.

A direct simulation of the canard configuration is not feasable as the direct simulation is not modeled. However it should be possible to adjust all of the factors for lift, stall etc to approach the desired scenario.

I have not done a Canard but have done some "tailess" aircraft. Some work will have to be done to get the proper AOA-pitch moment curves etc. You may be able to do this via a standard tail aircraft configuration, or by using negative values in a canard simulation. I have not tried this but it might be possible. negative values can do some highly unusual things! Take brakes for instance, a negative value will cause the plane to accelerate when brakes are applied and stop when they are released....

Good luck....T

 

[Killbilly]

The animation currently is correct. So is the one on the Long EZ
Think about it...on a canard if I want the nose to rise the elevator must move down to impart that force.

Yep, on a normal aircraft the tail elevator doesn't so much drop the nose as lift the tail. If you apply the same movement to a canard elevator on the nose it will lift the nose. The opposite elevator movement which would drop the tail on a conventional aircraft, will drop the nose on a canard with an elevator. Alphasim's EZ got the animation right. However, if the entire canard moves (instead of just an elevator portion), then that's another matter.