markhamregular

What would cause ailerons not to work when flying? The ailerons on myPT40work find on ground with the rods attached all the way out on the servo to allow maximum throw. But when the plane is airborn, I have to use the rudder to turn because even pushing the stick all the way right or left, all the planedoes is a little jerk. Noturn.

Thanks,

JohnBuckner

My Feedback: (1)

OK if the two pushrods are all the way out on the servo arm and the rods are all the way out on the torque rods you still may have not increased the throw much. To increase the throw the pushrods move out at the servo and closer at the control surface.

I,ve no idea about any little Jerk but if you are flying around close to a stall nose up, aileron response will be reduced.

John

rlipsett

we need to know how much the ailerons move to have a better understanding. buckner is right about if the torque rods are connected far from the center it reduces throw. a picture might help. if there is any play in the torque rods then you can lose throw by the wind forcing the surface straight to take up any slop

Lnewqban

I saw a similar thing in a trainer with a central aileron servo and torque rods not long ago.
The pushrods were so week that they bent when the ailerons had to overcome any load, like hand resisting the movement of the aileron.

Another possible situation is that the movement of the mechanism is obstructed by something in the fuselage.

May it be simply that the servo is damaged or not working under vibration?

KWJ48

Could the servo(s) be stripped? Maybe just a tooth or two. Might cause the "jerk" you were talking about.

JohnBuckner

My Feedback: (1)

Another possibility is the one or both torque rods are loose and sloppy around the exit hole of the trailing edge.

markhamregular

There is no obstruction inside the fuse. The servos are new. And they work well when on the ground.
I will measure the throw tonight and take a picture too.
By the way, the pushrods ARE all the way out of the control surface. Maybe that's the problem.
However, I remember checking the required throw and it was OK using the low rate since I do not have dual rates.

What's a stripped servo?

If they work well on the ground, how do I simulate any difference that might happen during flight while on the ground?

jetmech05

try holding on to the aileron with your fingers and try to resist the movement a little...see if the pushrods are bending.......that will simulate air loads....if you have a stripped aileron it will show up then as resistance then the servo will appear to slip.......
You may have a bad on off switch...when they start to go bad they can mess up things that don't make sense....or a loose connection somewhere.....
Another thought is interference...you say the ailerons are good on the ground with the engine running?...Are you using a metal clevis on a metal throttle arm to a metal control rod?
If so change the clevis to plastic...
Let us know what you find

Live Wire

To much dihedral in the wng will cause it just slide around and not bank. To check the stall in a servo ,I just holed the aileron with the tips of 2 fingers and move the control. The sureface should try or will move depending on output of your servo.

markhamregular

That plane has a LOT of dyhedral. I followed the instructions on the kit and used the highest dyhedral which now I wished I had not done. So the dyhedral make the roll even more difficult?
This is a plane that can also be constructed without aileron, but I never understand why a trainer that is supposed to teach you how to fly and prepare you for other planes would lack the feature that all other planes have.  

Live Wire

I will bet that is your problem. you have to overcome the thrust line but your weight is all below. Increase your throws a little at a time till you get some response in the air. Anouther thing , what size tires do you have on the plane. This trainer will fly 3 channel and the reason is all the weight is kept low in the fuse. As stated picks of out side and inside your plane will explain a lot.
Larry K

jester_s1

Does it actually roll at all in the air but not turn, or is it simply refusing to roll? If it rolls but doesn't turn without the rudder, you have adverse yaw. It's common with strip aileron planes, and the fix is to have more up throw than down (around 60/40 up vs. down is a good place to start). If it simply refuses to roll at all, then you have a linkage problem. As said above, make sure you are actually getting movement under load, both up and down. If your pushrods are weak, you will get down because it's pulling, but not up. That will make the adverse yaw much worse.

markhamregular

How do you get more up throw than down (40/60 as you said) if I have plain vanilla single rate 72 radio?

Sorry, but I am new to the hobby. And I am getting really frustrated not beeing able to land yet. Everytime someone flies the plane, they find a problem and recommend that I do not fly it until fixed.

I hope that aileron thing is the last.

Lnewqban

Don't get frustrated.

Be patient and enjoy the slow process of learning.

http://www.modelaircraft.org/mag/ftg...1/31main4.html

markhamregular

My tires are 2.5 on the mains and a 2.25 on the nose (as required)

This weekend, I am flying it alone, with or without ailerons. But before, as you guys sugested...
I will measure the throw, then try to hold the ailerons while using the radio, then if all is OK I will try to increase the thow by placing the clevis closer to the wing. Check all electrical connection and make a test flight that will also be my first solo landing.

Oh well! I am very patient, but until I make that first solo landing, I can't stop beeing edgy.

daveopam

My Feedback: (9)

I had one of those. The kit came with two dihedral braces. One brace had a ton of dihedral the other more like a normal trainer. The plane I had was built when I got it and it had a TON of dihedral. The ailes were pretty much worhtless. They would bank the plane if it was straight and level with a bunch of speed. If it was climbing or at part throttle, they did nothing. Another thought. If you don't use enough rubber bands, the wing will slide back a little in the air and the aile torque rods will hit the fuse.

David

markhamregular

David,

You are right, the plane will bank a little when straight and level but when climbing will not move at all. So everytime I find a good soul at the field who agrees to fly it, as soon as they try to make the first turn while climbing, they tell me I have no aileron. I wish I had used the bracket with less dyhedral. But now, I have to live with what I have.

Thanks,

AltaTed

I'm a newbie waiting for weather to even fly my trainer first time (with the help of an expert) and try to put my new plane in the air for the first time. I find this discussion very interesting.  I'm reading many of your posts to learn from these and don't really understand what dihedral means in your usage in this discussion. I understand it's basics as differntial angles between two planes but how it applied in these discussions? This may be important to understand for me and my planes first fly.

I'm sure knowing it will eventually become a common word for me. Please tell me more, probably in a new post "Dihedral" ?.

Thanks,

Ted

markhamregular

I am a newbie too, but after hearing "Whoa! This is a LOT of dyhedral" everytime I walk on the field, I know what it is.
The dyhedral is the angle of the wing. It makes the plane fly slower without stalling and recover any mistake you make.
It is a good feature but when there is too much, it can be a hastle.
I had a choice while building my kit (PT40) and I chose the recommended high dyhedral. Not a good choice.

If I were you, I would buy an ARF. Something like the Nextstar. In fact, I am really tempted to buy one now.
The kit ends up costing more, take about 50 or more hours to build and if you make any little mistake, you pay the price of frustration, when you should be flying and practicing landings.

Good luck!

jp_boud

My Feedback: (2)

Ted, if you look at your plane nose on, You will notice the wind has a nice " V " like shape to it. This is dihedral. Many planes, model and full scale have this built in because it increases stability by effectively lowering the planes center of gravity amongst other things. Like Harry said, too much of a good thing can be bad, but I wouldn't worry about that for now. just keep on that sim and getting prepared for that first flight.

Just to throw another term at you (why not learn everything at once) anhedral is exactly the opposite of dihedral.

http://en.wikipedia.org/wiki/Dihedral_%28aircraft%29

Campgems

Dihedral has nothing to do with flying slower and recovering mistakes. It does try to keep the plane level and when you use Rudder to induce yaw, it causes the plane to bank in to the turn. Slower stall speed is the result of the airfoil design, not the dihedral. Most planes with a lot of dihedral do have the high lift airfoils but it is the airfoil, not the dihedral that keeps them flying. The dihedryl does try to keep the plane level so if you let go of the controls and the plane is trimmed out OK, then it will regain a level flight within limits.

Don

Lnewqban

Is there a experienced RC pilot training you?

If you perform the check up that has been advised above, and the roll by aileron is still too weak, that dihedral will make you a better pilot.

Rather than a bad thing, I believe that the poor aileron roll of your plane, will force you to become proficient with your rudder and perform coordinated turns.

One of the reasons for the dihedral is to facilitate the turn of planes that have no ailerons by the use of the rudder only.

http://masportaviator.com/2004/02/27/using-the-rudder/

AltaTed

Great help on dehidral and I'm beginning to get a little picture of what you guys are discussing.  I did get an ARF high wing trainer 40" wingspan to begin my adventures in flying.  I'm a retired obsolete engineer who for the last 49 years was in corporate management, not on the board designing things. Thus I have much to learn and experiance to gain.

I'm in the Pacific Northwest just a couple of miles from the Canadaian border and the sound is down the street with a large wide open park perfect for flying right at the waters edge.  We have had rain and snow since early November so all I can do it pet my little plane and put in hours on the simulater waiting for flying weather. I hope by then I will find an experianced instructor to help me put my plane in the air the first time. There is a good RC club south of me that I'm 12th in line on their wait list to join and hope by the time our weather turns decent I'll be a member.  I know thats a big wish.

Ted 

markhamregular

I do not have an RC pilot training me. Everytime I go to the field, I find someone else willing to help.
It's great, but each time you hear something else.

I learned to fly a real plane and I solo after 9 hours. I find flying real planes much easier.
Once I make my first landing, I will gain confidence, which I need badly.
My home-built PT40 was not a good choice considering I am not very handy.

Don,

So, now I understand why the PT40 is designed to bank and turn using only the rudder if built without the ailerons. 
Thanks for the rectification.
Why do they tend to fly up like if they were tail heavy? Mine is properly balanced (I think, based on my CG machine) but it stil has a tendency to go nose up even at half thottle. Some expert at the field told me the plane has positive incidence and suggested I raised the trailing edge of the wing using foam strips at the back of the wing saddle. Would that help?

As I see it, a trainer with a huge dyhedral will teach you how to fly other huge dyhedral planes.

AltaTed

Back again with a little more. My ARF has flaps (I assume they are called), no alerons. Do you suggest at the beginning Inot use thethe flaps other than to trim it outand just use rudder and elevators to control it ? On the simulator I have become comfortable just using the rightsticks most the time but do occasionallu use the flaps making tight turns.

Without an instructor I fear I'll getsome bad habits doing it alone in my computer room all by my self.

Ted