Hello Everyone

I have just brought a new Supra Pro Competition and thought i had it set up but on test's today it was not happy going up the line,some of my club members said they think i've got too much flap on launch,it was going like a fish up the line very bad swinging violently.(or am i leaving launch flap in too long!!)

Im using the same setting as my other Supra which i had no problems with.

The transmitter i am using is Futaba FF9 so if someone could check there settings and let me have them that would be great or could check there movement on there Supra and forward them to me ever better.

I got the last settings off this website but just wondering if someone had a better set up to be honest.

Thanks.

Without seeing it I'd guess the tow hook is too far aft relative to the CG. I usually set mine at 3 to 4 mm ahead of the CG to start. On a calm day, or if there is a tailwind wind component at launch, I have to be careful to avoid a stall on the line in the early stages of the launch, which produces a rapid yaw away from the line similar to what you're seeing.

Just my .02 worth.

lc

Originally Posted by liftchaser

Without seeing it I'd guess the tow hook is too far aft relative to the CG. I usually set mine at 3 to 4 mm ahead of the CG to start. On a calm day, or if there is a tailwind wind component at launch, I have to be careful to avoid a stall on the line in the early stages of the launch, which produces a rapid yaw away from the line similar to what you're seeing.

Just my .02 worth.

lc

When i was laying in bed last night running throught the settings in my head and thinking about what it was doing i thought about the tow hook as well,I've now added another 10g of lead to the nose,and i shall check the tow hook this morning and see where it is sitting compared with the CG.

The launch trim is probably just a little hot side.

Originally Posted by liftchaser

Without seeing it I'd guess the tow hook is too far aft relative to the CG. I usually set mine at 3 to 4 mm ahead of the CG to start. On a calm day, or if there is a tailwind wind component at launch, I have to be careful to avoid a stall on the line in the early stages of the launch, which produces a rapid yaw away from the line similar to what you're seeing.

Or then elevator trim is little different from JGs other Supra. These differences are very different to measure. You just have to trim the plane hotter and hotter, and them come little back.

Originally Posted by RC-JG

(or am i leaving launch flap in too long!!)

This makes me think how you use launch camber in launch? You should have a setting that gives both - max tension and adequate stability - all through the launch. If not, then there is something wrong in the basic launch dynamics. Maybe you are trying to achieve launch trim with combination of relatively forward hook position and some up trim?

Some of us have then more complicated launch set ups. I use 2 stage setup with 2 launch phases. The second phase has less camber, but the second launch phase with less camber is not for stability, it is used for more speed.

Morning - To be honest i am using a slight bit of down trim on the elevator with launch camber.

I will check the tow hook soon and see where that is sitting with regards CG.

On my pro, I use the recommended camber settings. I have the hook just about as far aft as it goes, and then just trim the elevator to give a stable ride up the line. I would think that should work for you as well.

Originally Posted by burke757

On my pro, I use the recommended camber settings. I have the hook just about as far aft as it goes, and then just trim the elevator to give a stable ride up the line. I would think that should work for you as well.

Hello - Can i ask where you got your recommendations from,just to see if there the same as what i've got

How long do you leave the camber on for up the line ?

Originally Posted by RC-JG

How long do you leave the camber on for up the line ?

You need some camber basically all the way until start of dip. If you remove camber you are in danger of losing tension.

Many good pilots use just one launch phase. As I wrote, I have goine to 2 launch phases. First phase is about 10mm camber (at wing root), second about 6mm. If moment is good and tesiong is building quickly up, I change to smaller camber practically straight from launch, hepls plane speeding up. In very strong wind I use only smaller camber. Also if I have very good helper throwing the plane, I know I do not need the big camber. On the other hand, in downwind or sinking air lauch I use the big camber all the up.

The idea is to maximise tension. Tension = speed = tension = speed = tension... In launch plane is flying at high lift coefficient. If you suddenly remove all launch camber, you break up the acceleration process. Only very very short launches (sub 1 second) can be made without camber.

Is this the settings you are using http://www.kennedycomposites.com/ins...ra_Setup_2.pdf

Evening All.

Right my cg is 96 mm from leading edge and the tow hook was another 10mm behind the cg.

I have added another 10 grams of lead to the nose and moved the tow hook all the way forward.

On Vladimir's web page you can see that the CG should be set between 96 and 105mm from the leading edge (http://f3j.in.ua/media/supra-technic...cal%20data.jpg) - I'm flying mine set at 103mm
You can also use these templates to setup your Supra Pro http://f3j.in.ua/media/supra-instruc...nd%20Supra.pdf
The tow hook should be set few mm's ahead from the CG.

J'm

Forward tow hook and and little down elevator preset, the plane is overly pitch-stable in launch and wants to stall after the initial rotation.
As counterintuitive as it may seem, you'd probably better off by moving the tow hook aft and dialing a lot of elevator down trim.

Originally Posted by Francesco

Forward tow hook and and little down elevator preset, the plane is overly pitch-stable in launch and wants to stall after the initial rotation.

...or at least it will get directionally unstable when tension builds up.

Originally Posted by Tuomo

...or at least it will get directionally unstable when tension builds up.

That is not directional instability, it is one tip stalling earlier than the other.

Everyone - Do you have your ailerons set the same as your flaps on launch ?