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Apr 18, 2017, 08:30 AM
Registered User
Discussion

Modified Ailerons: Control rods options


I recently modified an F4U Corsair wing. It used to have a long narrow aileron and now, with short but wider aileron on the wing tip.

I didn't touch the servo placement area, so now i'm having a dilemma how to connect the control horns.

I have few options but i want to know your recommendations on which one is
1. Better (control power transfer)
2. Cleaner

Additional suggestion is also welcome.
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Apr 18, 2017, 08:40 AM
Registered User
IF.... IF you are going this way, the rod needs to be straight.

Giving it a "Z" bend does nothing for how the forces act on the servo and rudder horns, but it will create a tremendous amount of flex in the rod.

But I strongly recommend relocating that servo....
Apr 18, 2017, 09:05 AM
ARFs Are Me
TomCrump's Avatar
Quote:
Originally Posted by Brutus1967
IF.... IF you are going this way, the rod needs to be straight.

Giving it a "Z" bend does nothing for how the forces act on the servo and rudder horns, but it will create a tremendous amount of flex in the rod.

But I strongly recommend relocating that servo....
I agree. Neither of the two options pictured are satisfactory. The aileron servo needs to be moved .
Apr 18, 2017, 10:42 AM
Engine man
dmrcflyr2's Avatar
That should have been thought out before the aileron modification....
Apr 18, 2017, 10:59 AM
Registered User
You can cut a carbon fiber tube (about 4mm outside dimension) and slip it over the pushrod. This will add rigidness to the pushrod, without any other external support.

But there's no wonderful way to connect pushrods on an angle.
Apr 18, 2017, 11:03 AM
Registered User
What still is an (ugly) alternative, but mechanically sound, is a 90 degree bellcrank where the servo should have been.... at least that way you have straight loads on the horns. But aerodynamically it is less desirable (added drag).
Apr 18, 2017, 11:43 AM
Dinosaur
Twodor's Avatar
Move the servo.
'Z' bends that big is a bad idea. Brutus's bell crank concept will work but he has already said why it is not great. It's a foam wing. Relocating the servo isn't a big deal but I would consider filling the hole where it is now with a structural piece, either foam or wood.

Tom
Apr 18, 2017, 12:18 PM
Registered User
+1....

Whichever way you turn it, I think Tom is right... Plain as that....
Apr 18, 2017, 01:50 PM
AMA 537620
ChillPhatCat's Avatar
I don't believe that this wing is foam, it looks like the outer material is covering with a few spots showing minor wrinkles, and if you look into the servo well it seems there are ribs... I think that we're looking at a covered and painted wood model.
Apr 18, 2017, 03:49 PM
The runway is your best bet.
Mad_Mike's Avatar
Not to argue with these guys, they have way more experience than I do.

But how big is the plane? You can get away with murder on a small light one.

Also, it looks to me like you might be able to easily rotate the servo in the pocket to get the rod straighter.
Apr 18, 2017, 04:28 PM
Registered User
Quote:
Originally Posted by Mad_Mike
But how big is the plane? You can get away with murder on a small light one.
I did something like this on a small (40" or so) foamie trainer....
This looks like at least a .40 size plane or bigger, judging by the fact that it has scale retracts.
Apr 18, 2017, 08:19 PM
Registered User
It's a TWM F4U Corsair:

I have the thread of the mod here:
https://www.rcgroups.com/forums/show...4U-Corsair-46s
Apr 18, 2017, 09:24 PM
Registered User
Arceenut's Avatar
Move the servo. More work but put toque rods on the aelrons to bring the control in line with the servo.
Apr 19, 2017, 01:11 AM
Registered User
Hmm.. i think it's the dumbest mod ever without forseeing this one.

Anyhow, i like the bell crank idea.. at this point, function is the priority more than the looks. But where will i mount it?

Anymore ideas?
Apr 19, 2017, 02:38 AM
Registered User
Like I said before: Mount the Bellcrank where the servo should have been....


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