View Full Version : Spoiler- V-tail Setup

08-31-2006, 01:44 AM
I Have Just Finished A Cox Dust Devil But Am Having Problems With The Spoiler. I Am Using A Futaba 9c Transmitter And A 5 Channel Receiver. The Problem. The Plane Has A V Tail
The Spoiler Is Activated By The Throttle Stick(ch3), However, When It Is Deployed The Plane Takes A Nose Dive. I Am Trying To Couple The Spoiler With The Elevator Function But Am Unable To Figure It Out. I Have Looked At The Futaba Faq Site And Search But Cannot Find The Subject Addressed.

Anyhelp, Please
Robert Samuel

08-31-2006, 02:02 AM
Hello photos,

I would use two programmable mixes, the first with ch3 as master and as slave the right tail surface, the second ch3 master and as slave the left tail surface.
You'll probably have to play a bit with offsets, start and end points, but nothing difficult! ;)

09-01-2006, 08:21 PM
Thaks For The Help. The Final Solution To This Problem Was To Get The Spoiler Off The Throttle Stick And Assign It To The Flap Rotary Knob. Then Use The Flap Elevator Mix.

09-15-2006, 03:15 PM
Actually, the right thing to do is much simpler. IF you set up your v-tail right, then you only need one mix. I don't know if you have a 9CAP or CAPS, but it shouldn't make a difference.

You can use one of the linear PMIXes (1-5), but you really should use PMIX 6 or 7 and take advantage of the curve.

Go into PMIX 6, and go to the second screen. Then make the master Ch3 and the slave Ch2. Make sure that you have Link turned ON. For the first few flights, I would recommend having it toggle with a switch so that you can turn it off if you get the mix wrong!

Before you launch, go into PMIX6 again and leave the curve programming screen open while you fly. Get a good bit of altitude, and then open the spoilers halfway. Then, use the dial to dial in the mix to keep the glideslope the way you want it. Repeat the same procedure for at least 4 more settings. You should use these four points (plus zero spoil) so that you can know how to adjust your descent rate and speed with the spoiler.

Make sure you do this well away from the ground! It may take you a few flights, but will be well worth it when you are done. When you are satisfied, you can remove the toggle for the mix and just have it active all the time.


09-20-2006, 06:39 PM
On my initial post, I indicated that I was using a 9C Futaba transmitter. It's really a 7 C . Hope you have a solution for this Trans.

09-21-2006, 11:48 AM
Does the 7C have non-linear curve mixing? I am sure that it has a v-tail mix build in.

09-21-2006, 05:41 PM
Not As 1 Can See

09-23-2006, 05:08 PM
Well, then the linear mix will have to do. Unfortunately, as many glider drivers know, that mix is very seldom linear. What you need to do to set it up properly then is have one point you are very comfortable with - whether it is 50% or 100% spoiler deployment, and make sure that you set the gain on the elevator channel to hit your desired glideslope at that point on the curve.

After a few flights, you will get very comfortable with the glider and you will know the spoiler "range" that you use the most on approach (I would guess you will go from zero spoil to 75% or 100% very quickly. That is where you want to make sure that the mix is working, and just get comfortable that you will likely have to feed in a touch of up on the low side of the mix point.

Good luck and have fun.

10-04-2006, 01:38 AM
I use the flap/elevator mix for spoilers. Set up for two flap servos. Put your spoilers in 5. Use flap/elevator mix. I have mine activated by the left side slider.

Set servos so that when the left slider is all the way up the spoilers are down

The mix has two values for elevator. The first relates to the first part of the sweep of the slider. The second is for the second half of the slider sweep.

Your % will vary but I think I have my elevator up 5% for the first part of the sweep then up to about 15% for the second half, depending on the plane.

Works fine for me.