wing design/control

[keith83]

I recently bought a beginner plane from a name brand Mfg. (Great Planes).
Compared to other planes and things i have read about wing design it seems strange to me. each panel is 12 X 20 about 5/8 thick. Flat bottom. Leading and trailing edge are 3/16 carbon rods. dih. is around 6-8 deg.
The problem i'm having is control. The plane hand launches well (after updating power) and flies straight ahead. It seems reluctant to turn but once it does it wont stop turning. Full oppisite rudder wont change it. All i can do is chop the throttle and let it spiral to the ground. This is true for both directions. Part of the problem is that i'm new but this plane flies nothing like the e-fly on the sim. I have increased throws past spec and have added some rudder area with tape. Plane is balanced per spec. Should i just start over with a more "conventional" plane?
I am getting frustrated and cant turn this over to my grandsonto fly.
Thanks all, Keith

[Ollie]

Your ideas about turning are the stubbling block. You need a teacher about flying skill.
First, the function of the rudder makes the plane yaw. Then, the yaw, through dihedral, makes the plane bank. When you have enough bank, then return the rudder. Also, the turn speeds up and goes into a dive. So the elevator needs a little up control for level turn. It takes your rudder and elevator control timing for a nice turn.

You need a flying teacher!!

[Ollie]

Ditto. Sorry.

[fhhuber506771]

pic of the plane might help (or name of the kit...)

There are a couple of possibilities other than simple lack of experience, but to check on them, we would need to know which model we are dealing with.

Assumming its a 3 channel trainer type, built correctly, it should respond as Ollie says. but that is not necessarilly a pair of good assumptions.

[keith83]

Thanks guys. It is called a "yardstick". I'm sure that i need lessons but i would have thought that enough opposite rudder would bring it out of a turn?
Others on here have said that it is a good plane with increased power.
I thought the very low aspect ratio of the wing odd for a floater but no one commented on this. Just installed a new gearbox after bending the shaft. I will try to change the way i turn next time out. Keith

[fhhuber506771]

if the plane is near stall speed, then the rudder can sometimes not work well. Try to maintain speed. If you are at a slow enough speed for that to be what it is... you are asking to fall out of the sky.

Shallower climbs and keeping the speed up SHOULD help.

The basic design of the plane is good for a trainer. Not a plane I would normally recommend for unassisted learning... wood structure is a bit fragile for the bumps you'll give it.

If its possible to get someone with experience to trim it out and give you a couple of pointers in person, it would save you a lot of repairs.

[Sparky Paul]

I have several Yard Sticks. With 8-cell power they can do everything a plane in that class can, plus.
It doesn't need any more rudder area.
You may be holding the plane into the turn too long. None of mine have shown any tendency to stay in a turn once I release the rudder.
Is your servo operating properly?
Returning to neutral when you release the control?
The wood parts aren't fragile, the plastic parts are.
The motor mount will break, and the wing supports also.
Here's a few of mine:

[vintage1]

If the model can't be got out of the turn and doesn't do it naturally you simply have not got enough dihedral.

You need 5-7 degrees on each side to be safe.

[Sparky Paul]

The dihedral is built-in with plastic parts, on the YardStik. There's more than enough.

[keith83]

Thanks guys. The HS 55,s are cycled before each flight and seem to be OK.
Air speed shouldnt be a broblem as this is suposed to be a "walking speed" plane.
Sparky your right , the stock motor mount broke with the first "landing"
I glued on a "stick" and installed a GWS 300 D drive.
This worked well but after bending the shaft i have installed a 350 C drive.
I'll try it again soon. Keith

[Sparky Paul]

Keith, the YS is so inexpensive and easy to assemble, it's a good test bed when you don't spend any time building something to try an idea on.
Mine have various motor-gearboxs from other planes now. The GWS gearbox and motor set is another aid to quick assembly and flight.
With the GWS D gearing, 11x7 and 11x8 props work fine on 8 cells.
Your control problem is puzzling, though.

[fhhuber506771]

I think he's expecting it to be able to fly too slowly...

"walking speed"... well, yes its a slow plane but 5 mph and just about everything heavier than a microfilm covered indoor FF model falls out of the sky. and... too slow, the rudder may not have the authority to do anything. (and adding a little flying speed is about the easiest solution to try)

[marfish]

Keith, it sounds like you have too little dihedral in the wings. Are you trying to use the rudder like a steering wheel for a car or handlebars on a motorcycle? Planes don't fly like a car or else they'd be on the ground all the time.
Rudder only turns usually produce only a spiral dive and are difficult to recover from with just rudder control.
Try this exercise. Hold the plane out in front of you. Now, give the plane Left rudder control. In slow motion, make the plane do the motion that the rudder tells it, i.e. tail swings right, nose-left. Now, since the plane's wings see different air forces it will bank over to the Left as well. At this point STOP. The plane should be in a Left bank, rotated Left slightly from the original heading, and in some kind of dive(because as the wings bank over your rudder begins to lift the tail UP-nose DOWN and the wings are no longer holding the plane up vertically. Examine the model carefully. Which control surface will now be needed to complete the turn? Correct, the elevator because the horizon has changed position relative to the plane or vice/versa. The horizontal turn is performed by banking the wings first and then, adding some amount of UP stick to pull the nose around the rest of the turn, since the plane flies in 3-D space.
Just my thoughts,
Marlan

[sajeev]

Keith, sent you a PM.