Balancing Control Surfaces on Yellow P-47

Balancing Control Surfaces on Yellow P-47
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Balancing Control Surfaces on Yellow P-47 - 4/3/2002 9:59:10 PM

k_sonn

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I am about to start building a Yellow Aircraft P-47. All of the control surfaces are made from fiberglass. How do I check to see if the surfaces are balanced? How do I balance them if they need it?

Balancing Control Surfaces on Yellow P-47 - 4/4/2002 3:19:27 AM

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The Yellow P-47 that I have has metal weights in the leading edges of the ailerons, therefore, I believe that they are somewhat balanced at the factory. I don't think that other control surfaces suffer flutter as much as the ailerons do.

Any further help on this subject would be greatly appreciated as I was going to trust the Yellow design as is due to the large number of posts stating that Yellow P-47s and Spitfires are great designs.

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hinge line - 4/4/2002 4:00:54 AM

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Guys, The trick to keeping the '47s ailerons from fluttering is to move the hinge line INTO the aileron, so that the metal weights are IN FRONT of the hinge knuckle. You can accomplish this by extending the hinge that goes into the wing with brass tubing. Simply put the hinge into brass tubing of the appropriate size, crimp the tubing around the hinge and cut the tubing so that about 2 inches goes into the wing. This will extend the hinge knucke far enough away from the trailing edge of the wing to allow the weighted portion of the aileron to move ahead of the hinge line. The other alternative its to ditch the fiberglass ailerons and build new ones out of balsa that are lighter.
Hope this helps.
Evan Q.
PS. I did this on my yellow spitfire and it does NOT flutter at any speed.

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Y/A Jug - 4/4/2002 4:38:26 AM

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k_sonn,
Having built a couple of these, and been around a few folks that have built this plane, I can tell you that every technique works that you will read about.

Here are some simple, easy ways to ensure that the ailerons wont flutter on you.
1. secure the servos inside the wing cut out and not the hatch.
2. Use 4/40 wire or larger from the servo arm to the aileron control.
3. Make sure that your control rod coming out of the aileron is secured into some kind of dowel or hardwood.
4. Use a nice high torque servo, I have installed 615mg by Hitec with no flutter issues.
I use sullivan golden cleveses, and a brass tube over the 440 fully threaded rods.

Thats it! I guarantee it.

Ray

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Aileron - 4/4/2002 4:38:59 AM

L454S

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Evan is right, if you dont do it like he says,it WILL put the plane back in kit form. I would just ditch 3 pounds of weight and build a couple LIGHT ones and reduce overall weight.

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Balancing Control Surfaces on Yellow P-47 - 4/4/2002 7:52:27 AM

fw190

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Lenny has the best method, rebuild them from balsa and save a bunch of nose weight!!! I nearly lost mine 2x and hoping there won't be a 3x.

fw190

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Balancing Control Surfaces on Yellow P-47 - 4/4/2002 8:04:21 AM

Vince

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I have built up ailerons on my P47, with Hitec 5645 digitals, 1/8" titanium welding rod, threaded 4-40, with Sullivan clevises. This hardware is attached to a 8-32 screw which is anchored in a 3/4" wood dowel built into the control surface. I have not had any flutter issues. Having said that, my flying buddy had a Yellow P47 with the fiberglass control surfaces. He did not go to the extent I did to reduce flutter. He just followed Yellow's tips. He had no flutter issues either FWIW.

Vince

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P47 Aileron flutter - 4/4/2002 9:12:39 AM

DOC

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From: Chino Valley, AZ, USA
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Kirk, I have built and flown 2 of these birds!
Build your own ailerons and save the 2-3 pounds of weight.
I think the most important rule is to use metal geared servos.
The metal gears won't strip. You will get the flutter when those nylon gears flex and strip.
Also the hinge pivot line should be extended back to the radious of the aileron leading edge, as previously suggested!
Good Luck,
DOC

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Balancing Control Surfaces on Yellow P-47 - 4/4/2002 9:55:54 PM

k_sonn

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Thanks everybody for the valuable information.

Ray:

[QUOTE]secure the servos inside the wing cut out and not the hatch[/QUOTE]
Do you have a favorite method for doing this?

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Balancing Control Surfaces on Yellow P-47 - 4/4/2002 10:34:03 PM

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Start by lining the well with 1/16th light ply epoxied in place. Build up a floor out of ply until your servo arm can clear the wing bottom enough for your personal range of travel. I shoot for as much throw as I can get, using a Dubro heavy-duty, long servo arm. Supports are then built up out of hardwood, and surround the servo on three sides; they go from the floor, to the height of your servo, as it lies on its side in the well. A laminated, or light carbon strap is cut to the size of the servo footprint, then glued with silicone to the servo that is lying on its side in the well, 4 #4 button head screws are used to secure the servo in place by going through the strap and into the hardwood supports. Very solid, I use this method in 90% of all servo wing-mounting situations.

Ray

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Balancing Control Surfaces on Yellow P-47 - 4/4/2002 10:45:38 PM

k_sonn

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Thanks Ray. I will use that method.

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Hinge line - 4/5/2002 7:32:18 PM

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Ramtec, Either Im explaining it wrong, or your misunderstanding me. What Im saying and it is indeed possible because I have done it, is to have the hinge line BEHIND the leading edge of the aileron. This indeed creates a small see saw effect which is the way full size ailerons work. Those lead weights are supposed to balance the rest of the aileron, just like balancing an airplane on the CG. The hinge line becomes the CG, the lead weights are in front, and the rest of the aileron is behind the cg. If an aileron is perfectly balanced, statically, it will stay in any position you put it in. Now its not entirely perfect, but close enough to reduce the possiblilty of flutter. I almost lost my first Y/A t-bolt to aileron flutter. I removed the leading edge hinged ailerons and did the aforementioned modification and never had any more problems with flutter at all, So I can claim that it does work.
Evan Q.
ps, It is easier to do the balsa ones IMHO and I plan to do so on my next t-bolt

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Love these debates - 4/6/2002 5:41:17 AM

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...my last $1.25,
1. Evo is right. Here is another explanation. When you drill and insert your Robart hinge points, the hinge will stick out say 1/4" from the sub trailing edge of the wing. When you drill the hole for the aileron leading edge, go back and with a dremel or small smooth rat tail file, clear away the material that blocks the aieron from travel.

2. You can follow the building instructions that Yellow give you, and do nothing but make sure you step up the servo strength and you will have no problems, provided everything else is glued in nice and solid.

3. The easiest way to get around the potential flutter concern, is to do like most echoed and just rebuild it from balsa, me, I say why, damn things look sweet. I would take the time that it takes to build up my own, and put it into making sure that the Yellow ones are installed soundly, end of story.

Testament to this fact, I have a Jug flying that I built for a customer that is flying with a Brisson 4.2, (my guess is that all of you with flutter problems havent even thought of flying with an engine this size) dont think that puts alot of stress on an aileron? To quote," flys straight and true, with no problems". If you are in Jackson TN, be on the look out for it.

The final word hopefully is this, yes when you build the Yellow Aircraft Jug, take notice that you MUST address the fact that the ailerons will take you a bit longer to rebuild/install, reinforce and rig.

Of planes types and flying qualities, if all I ever had to worry about was the Ailerons, I would be truly a happy camper. The Jug is a great flying plane, ask Vic, I want to take his simply cause he doesnt fly it "right". Do ya Vic?

Ray

< Message edited by AirRayInc.Com -- Apr 6 2002 2:36AM >

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Balancing Control Surfaces on Yellow P-47 - 4/6/2002 7:15:13 AM

Vince

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The flight surfaces are built up balsa on the Bert Baker P47, which became the YA P47. The plans show 3/32" sheeting with 3/32" ribs, 3/4" balsa leading edge, and 1/4" balsa end caps. I drilled the leading edge and epoxied in hardwood dowles for an 8-32 all thread control horn.

If you would like, I can xerox the ailerons on the Bert Bake plans and mail them to you, but they are really simple to construct. The hardest thing is getting the angle for the sheeting on the leading edge correct.

email if interested

Vince

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