Sealing off Control Surface gaps
 

Hi all,

I know this has prolly been discussed before, but need to know how loose/tight should I keep the monokote when covering the control surfaces(hinge areas). I understand for it not to be tight as nothing will work or it will burn out the servos, but again I don't want the covering to be too loose. Any suggestions would be appreciated.

THANKS much in advance.

Sealing off Control Surface gaps
 

The way I did mine was with clear tape. I did one side of the gaps (bottom on ails and hor stab) I did not notice any additional tension in their movement. The gap fill only covered the tapers DOWN to center. Installed at full deflection to allow good access.

Sealing off Control Surface gaps
 

mikenlepaz is right.

Install the gap seals with the control surface deflected fully in the direction opposite the gap, and tightness won't be an issue.

What you gain in maneuverability and safety (flutter reduction and hinge "insurance") is definitely worth it.

If you want to test this first, clean your plane, and use a strip of ordinary clear adhesive tape, on the underside of your surfaces and go fly. You'll see the improvement in control response immediately.

Sealing off Control Surface gaps
 

I totally agree with Mike James. I cover most of my planes with ultracote, so i just seal them with ultracote at the same time as I cover them. Works real good. Clear also works real good.... You will notice a difference too. Good luck.................

Small suggestion
 

Not to stir the pot, but use the tape on the top surfaces, it will not collect dust/grass/whatever that way. Well worth the 10 mins. it will take to install.

Jetts

Sealing off Control Surface gaps
 

Try to get it into the "V"

Sealing off Control Surface gaps
 

When useing clear tape, why do you say use on ONE side? I have been useing clear tape for a while and have always taped both top and bottom. As MikeB stated gp full travel and get tape down in the V. Never had any problems.

Sealing off Control Surface gaps
 

Because you only need it on one side. Why add the extra resistance to the surfaces if it's not needed?
Dennis-

Sealing off Control Surface gaps
 

Just wanted to say Thank You all for your input on this topic.

Was very helpful and sure will use the techniques used here.

Thanks again :)

Like this...
 

I used monokote to seal the hinge gaps...

Sealing off Control Surface gaps
 

I always use matching covering material too. Just about completely invisible.

Sealing off Control Surface gaps
 

I also use Utracote to cover my planes. Ultracote also makes a clear. It is especially handy when you have multiple colors going through the movable surfaces. It also works well over Monocote.

Both sides
 

I mentioned above to put clear tape on one side (the bottom) while TESTING. Why? Because, whatever pressure differential exists on the flying surface will tend to "suck upward" through the gap. Placing it on the bottom (only) will let you test it. It is somewhat more likely that it would be blown off, if only used on the top side. No bigee... just a detail.

If you like it, as I bet you will, then it would probably be best to seal both sides. I always do it, during the covering process, using the covering material itself, rather than tape.

Sorry if there was any confusion about this.

Top hinging
 

Using a top surface edge hinging with the covering has always been an effective option. Always check your gap and movement before hooking up your linkage. There is some gapless iron on hinging material on the market as well. If the movement is not good it would be time to do it over. What plane are you worried about? Jim

Re: Both sides
 

Yes... If the control surface is deflected downward.

However, if the CS is deflected UPward, the pressure will force air downward through the gap.

But really, there is still no need to do both sides. The pressure is not going to be so great that it will blow a piece of tape or covering off (unless it's not attached well).

If you feel more comfortable sealing top and bottom, go right ahead, but it would be like putting two Band-Aids on the same cut.

Sealing off Control Surface gaps
 

What about sealing fabric coverings? Have a monster on the bench and flutter always concerns me...

Sealing off Control Surface gaps
 

No matter what you should always cover the gap in the control surfaces, that is what Dave Patrick said in his book and I have to agree with him.

Sealing off Control Surface gaps
 

jucava, I understand the importance of sealing the control surfaces, I've lost a couple of planes to flutter. What I don't know is what to use on a fabric and dope finish. I'm not sure if the dope will take the heat from the iron to use clear mono. Maybe a piece of fabric doped in place, let it dry and then break in the seam to allow it to move freely or will the fabric stress and fail? Anyone know the answer to this. Sorry, my previous post doesn't read very well.

Sealing off Control Surface gaps
 

I always seal both sides. Weight is not a factor and i always felt that it just made one big hinge. I seal the two sides together in the gap and feel it can't hurt the strength of the joint. Might be overkill but then, i've never lost a control surface.

Sealing off Control Surface gaps
 

Pushrod, try plain ol' scotch tape. I have used it many times. Packing tape would be better due to it's durability, but either will work.

Sealing off Control Surface gaps
 

Thanks Mike,

Wasn't sure on the fabric finish. Hate to lose a 1/3 scale Waco because an aileron doesn't want to play anymore. The build continues, and can be seen here on RCU under "User Product Reviews".

Thanks again,
Bruce

Sealing off Control Surface gaps
 

If you use packing tape do you use the full width of the tape? Or do you cut a narrower strip?

Also if you put something like windex down first would it give you some play time to get the tape straight but still seal completely?

Thanks for the help.

Ray Crane

Sealing off Control Surface gaps
 

If you were gift wrapping a package, would you use the entire width?

The answer depends on how much time you want to spend doing it. But either will work.

And yes, windex will help.