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Old 03-26-2008 | 07:04 PM
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Default Construction question

Hopefully the pic comes through. But was mounting the ailerons onto the wing of my LT-40 and noticed that the Rods don't line up as noted in the picture. But should these be in alignment or can they be off set a little - will this affect performance if left in this fashon? I think all I need to do is realign the hole in the aileron to fix the problem and make them closer together as they aren't permanently attached at the moment.

Also, another question, as I am bulding another plane (building is contagious) and wonder just how much warp can be corrected in the trailing edge of a wing. Plane is a Piper Cub 20 that I have a OS 30 4 stroke to put in. The problem I have is that the trailing edge isn't straight and true. The piece when laying flat on the table (doing a trial fit) the left side is raised off the table about 3/8" and the right side 1/4". I think I need to either order a new set or just make my own. All the other pieces are much better but these 2 are bad.

Appreciate the help - Hansen
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Old 03-26-2008 | 07:16 PM
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Default RE: Construction question


ORIGINAL: Hansenr

Hopefully the pic comes through. But was mounting the ailerons onto the wing of my LT-40 and noticed that the Rods don't line up as noted in the picture. But should these be in alignment or can they be off set a little - will this affect performance if left in this fashon? I think all I need to do is realign the hole in the aileron to fix the problem and make them closer together as they aren't permanently attached at the moment.
The two torque rods should be at approximately the same position when the ailerons are centered. Now with that said, you can get by without it like that but it's not the best solution. If you can correct them without too much trouble then I would. But if correcting them is going to be major then you can leave it like you have it and simply adjust the length of your pushrods to compensate. Like I said, while it's not preferred you can get by with like that.

If you don't have the ailerons attached yet you can probably correct it pretty easily. Simply hold the one side of the torque rod pliers and use then use another set of pliers to "twist" it a little bit so that they are even.

Ken
Old 03-26-2008 | 07:49 PM
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Default RE: Construction question

I wouldn't think that this would cause any sort of differential, based only on this vertical position. I guess it goes into the collumn that would prompt you to examine the components before assembling that part of the wing, although I would also assume that these parts should be identical but opposite without the difference in the angle like that.

I had one that was supposed to be center servo (single servo) for the ailerons. I converted it over to dual serovs by building a little box that was supported by reinforced ribs at the center of the wing/aileron point. I ground out the torque arms using a Dremmel Tool (spelling..). It worked out very well. I think it was the Four Star 40, but I can't be sure. That was several years ago.

So, if you are having problems with that, just cut them out (the torque arms), and put in two servos.

CGr.
Old 03-26-2008 | 08:23 PM
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Default RE: Construction question

There would be a good deal of diference in throws if things are as the look, about 20 degrees difference when the ailerons are centered. CGr has the best idea, put in boxes for servos in each wing. My trainer was giving me fits when I discovered that the arms were wobbling around as there was no bearing on the torsque rods, just soft balsa. I drilled a #60 hole through the top of the wing right next to the L near the root and fed a jewelrs saw blade through and cut off the arms. It took a couple blades for each aileron as I kept snapping them. I then cut off the rods they exited the wing area pulled what I could from the ailerons. Then I used mini servos, one on each aileron. Worked very well. So well in fact that I'll never use another troque rod setup.

You don't need much horse power for the ailerons and a couple mini serovs will has equal or exceed the torque of a single standard. My mini's were something like 31 in/oz and my standard was 53 in/oz. I ended up with a net gain in torque in the process.

RCken pointed out the fix if you want to keep the torque rod setup. Simply bend the arms so they are at 90 degrees to the cord line of the aileron. You are lucky to catch this before things were glued together.

On the warped wood. It s dificult to get really straight wood. If you have two sticks that are warped, and about equal in the warp, you can use them to pull against each other so the result is straight. IE two warped spars, Install the upper and lower so the warp in in opossing directions to offset the warp. where you run into real trouble is with sheets that curve along edge. These need to be cut straight before using. If the wasp is along the face, then just use the two spar trick and set the upper and lower opposing each other to end up with a flat.

Don
Old 03-26-2008 | 08:42 PM
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Default RE: Construction question

Campgems is 100% right. The arm on the right will bind and not allow as much "up" as the other side. Since they are not secured fix as RCKen suggested.

Happy Landings!
Old 03-26-2008 | 11:02 PM
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Default RE: Construction question

When you mount the servo's arm...You'll notice it's not going straight, straight anyway.
Use two pairs of pliers and bend it a little and just large the holes.
Yeap, hold the drill more stright the next time u drill the ailerons.
Don't worry it dosn't have to be straight, straight. becuase the servo's arm won't mount stright to being with.
That's what the threads on the cleves and the rods are for.
Btw, some elavators , you use a rod piece to joint them. They're harder to fix after you glue.

if you a havn't glued..switch the airlerons for left wing to right wing..and redrill.
or just bend the rods to compensate



well, for you second question. Sometimes it's not suppose to be straight.
Depending on the model. It's call a wash out or wash in.

you can try to warp it back with the covering, when you cover.

Even if you did have straight and true, you might wrap it when you cover.
Old 03-27-2008 | 07:49 AM
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Default RE: Construction question

I appreciate the help and will work on the suggestions tonight.

Cheers - Hansen
Old 03-27-2008 | 10:17 AM
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Default RE: Construction question

If used while they are as missaligned as the picture shows, you will have serious problems. IMHO a fix would be mandatory.
Old 03-27-2008 | 10:56 AM
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Default RE: Construction question

I quit using a single servo for ailerons years ago.

Put separate servos in each wing and you'll be glad you did. Depending on what radio you have dual servos can be used for different things as you progress.
Old 03-27-2008 | 08:55 PM
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Default RE: Construction question

i agree if you can remove the aleron just use two sets of pliers one to hold the other to bend the rod until it is even.that would be the easy fix.
Old 03-31-2008 | 07:51 PM
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Default RE: Construction question


ORIGINAL: JRFisher

I quit using a single servo for ailerons years ago.

Put separate servos in each wing and you'll be glad you did. Depending on what radio you have dual servos can be used for different things as you progress.
Hi,
I'm putting servos in a wing now, what is the best servo for a fatuba fm system in the wings? Its not a thin wing core , and its a trainer. Its about 1.3 inchs thick, I could use a reg servo if the weight is not a problem.
thanks
Old 04-01-2008 | 05:41 AM
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Default RE: Construction question

On a 40 size plane standard servos are sufficient. I use nothing but ball bearing servos but that's not necessary. I use them because I have them.
Old 04-01-2008 | 10:45 AM
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Default RE: Construction question

Well, used the pliers to tweek the Aileron linkage and worked like a charm. Now to do some sanding and covering this weekend.

Cheers - Hansen

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