I need some advice...


Is there a way to control the canards individually by using only the 2 servos which will be controlling the elevons?

The way I picture it when connected to the elevons.. Right elevon goes up and right canard goes down... not right is it?

I think both right elevon and canard are supposed to go up...


Anyone have any ideas how to do this?

When the trailing edge of the right elevon goes up, the trailing edge of the right canard should go down.

Hope this helps

I was thinking that as I applied some up elevon the leading edge of canards would also go up....

So, it is possible then to use only 2 servos to control both canards and elevons: 1 per side?

No. Not without adverse effect.
There is
Pitch e.g. Elevon te up \, canard te down /on both side. This would cause lift. E / C\ down.
Roll e.g. Elevon on one side te goes up \, Canard goes up \ while the other side does the opposite E/ C/.
So with two servos with mechnical links you can't get the canard to switch functional direction.

We have this setup on the FW/HL EF2K and it requires 4 servos if you are going to have the canards maintain both roll and pitch.
Some used 3 servos, one on each Elevon, for pitch and roll, and one to control both Canards in pitch only.

Well, this is what I have.. I added video of the canards moving..




[link]http://www.rcgroups.com/forums/showpost.php?p=15093733&postcount=123[/link]

What I did wrong was connecting the canards to the servo arm on same side as I have the elevons. As you can see on the video.. When my Elevons go up, my canards go down. I think I should have connected the canards on the top side vs. the control horn on the bottom side..
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That still wouldn't help.
Delta Elevons have pitch and roll control driven by two servos and mixing. Add canards and roll has to work the same but pitch has to work the opposite. so the servo can't supply the two inputs in the opposite direction at the same time.

The way you have it your canard fights the elevon. If slow flying high alpha its fine but at speed this acts at first like speed brakes and then forces a stall. depending on your cg one wins over the other but with a lot of fowles air.

If two servos are a must, split the elevons, put one servo on the canards linked to the inside elevons for pitch control; up and down
and the other servo on the outside elevons for roll control only. Infact if you got creative you could go old school and attach a link from the pitch control servo to the roll control servo on a slider. This still will not allow the Canards to have roll control which is fine.

In this manor neither surface will work against each other, and this is the common flight config for slow to sub sonic for these types of aircraft.

Would it be too much to ask of you for a rough schematic of what you are talking about.. lol

I'm like ... UUuhh!!!

How about the above

Thankx.. but I was still left scratching my head with that one..

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UPDATE!!

I've done it....

Found the proper way to connect 4 moving surfaces with 2 servos. Offcourse the easy way would have been to find the answere to what I was wanting to do by simply doing a search.. Believe me, I did search far and wide... It's realy preety simple, but since I had never done this... I didn't know where to begin. After several attempts and different ways of connecting the canards and still come to the surfaces not working the right way, I found it.

I don't know what people call this set up as I did not get the idea from Google. At this time all I can name it is " The Criss Cross and Under Connection".

My left and right canards are cross linked connected to both Elevons, but instead of being connected straight forward they cross themselves at center and also cross the fuse to the opposite side of aircraft body..

Look at the pictures..

Congrats;

Trouble with looking at your pictures and video is it doesn't show it working in roll and pitch and you first comments were saying you didn't get it working. I'm surprised because this could be used in other applications using two larger servos instead of four small and this allows gyros to be thrown in much more easily.

Actually this could be set up differently to work Tailerons and Aileron/flapperon off two servos also. I think I'll try this!

All you need is to link up some thrust vectoring

Maybe this picture will show just how I have set this up..

I connected the Right elevon to the left canard. Tne right elevon is connected to the bottom of the control surface, using a double arm... I connected the left canards going from the top of the wing at the servo arm.. through the fuse and under the airplane to the bottom of the left canard. The left elevon is connected in the same fasion toi the right canard. When I give full up elevon, both canards also go up..

When I wige full down... both canards also go down.. When I give right bank... the right elevon and the left canard go up and left elevon and right canard go down.. Making this a top in the skies. Making this JAS-39 stop on a dime should be easy... Cobra anyone!!