Custom Design Canard

[Crazyflyer]

Here is my first project, a design of a futuristic canard plane (small wings at the front, motor at the back) I sketched up a few years ago.
This is an early proof of concept prototype made using foam, not sure what the next level will be.
I will most likely shrink the fuselage, and even though the wings seem a bit small, it does glide nicely when throwing it around the house!!
I will probably be adding winglets on the main wings, and not sure if I will have a rudder ... or two.
The dimensions are currently 24"x24", I will have to figure out whether I should make it larger in order to make it easier to add the servos, motor and batteries.
Because I would like to add more compound curves around the wing/fuselage connection, not sure whether I should stick with foam or try my hand at balsa.
I find that this foam is too flexible for the wings, I am thinking of fiber glassing the whole plane for strength if I do stick with the foam structure.
Suggestions or ideas on construction are very welcome.

[Wingnutz]

Where does it balance and how did you balance it?

[Crazyflyer]

I did not balance it yet, but I am guessing from initial throws that it will be at about 1/3 from the back once I have the first flying prototype. as it is right now, it about 45% towards the back but I still need to shave the front quite a bit.
Someone suggested I adjust the canards 5 degrees up, throw it to the horizon, once it is balanced it will go straight. All this before putting in any of the electronics.
As it is right now, it goes down gently but still nose heavy.
I am sure I will go through a few prototypes before it can fly properly ... but hey if one of the TEMAC members can fly a lawn mower, I am confident I will be able to fly this thing!!
I am currently figuring out how I will control the canards, most likely with a single shaft that will also also act as the hinge to the elevator.
I may also use a similar system for the ailerons to have a clean look, not sure if I should use a single aileron servo in that case. (attached is quick sketch of my thoughts).
I hope to have the first flying prototype within 2 weeks.

Stephan

[Frank v B]

Bill and Stephan,


I found two articles in a stack of magazines donated to the Club by Ken Ross on canard design.  One of the designs is close to the Piaggio and another is close to Stephan's project.  I will bring the articles to the Zone meeting next Sunday.  This may help answer the CG question.


Frank

[Crazyflyer]

Well, this afternoon will be the first test "flight" ("flight" because I have no idea if it will even take off!!  )
He are pics of my very rough attempt at a quick prototype. The plane is quite heavy for the wing area, my next attempt I will probably make the whole plane larger and increase the percentage of area of the lifting surfaces.
For the first flight, I have added some makeshift wheels for takeoff (original idea was to hand launch), I think it will be a bit safer for the plane in case it decides not to fly!!
At this point, the CG is about 1/2" in front of the leading edge of the main wings.

Stephan

[Crazyflyer]

Welllll  The test flight wasn't a huge success, as suspected the main wings didn't have enough lift for the weight.
It took 3/4 of the runway before it did a violent back flip.
Reasons I am guessing are:
- Throw on the front elevators were too much (I pulling max as I was afraid it wasn't going to take off)
- The main wings needed more lifting surface to increase the stall speed (it needed a lot of speed to create lift with such a heavy battery)
- The CG needs to be brought forward (surprisingly it was at 1/3 towards the back and needs to go forward)
- Andy and Greg were watching which put too much anxiety on the plane's fear of failure  (clinical term is aeroctil dysfunction)

Good news is that only the prop adapter sheared off, and the vertical stabs broke, the prop is surprisingly in good shape.

So next week it will have new larger wings and the battery moved forward. Hopefully I will avoid aerobatics 6" from the ground!