FUZZ

I have built a few planes now and I consider myself an average builder. My question is this, How is the best way to seal a hinge gap with monokote,... from top or from bottom etc,..etc,.. I have never had a problem with flutter as of yet but I see where many people suggest sealing the hinge gap. So I am just looking for some techniques that others use to do this. And if possible could ya post some pictures.


Thanks,
Johnny

MinnFlyer

My Feedback: (4)

Hi Johnny,

Seal the gap from the bottom, that way it doesn't show. Use a long narrow strip of covering and fold a crease in it. Then bend the control surface all the way and iron the covering into the gap area. See Photo:

FUZZ

Thanks Mike,

That made it clear as a bell with the picture. Thanks alot.

Johnny

TRP

My Feedback: (1)

Humm.. I did just this thing last week.

Are there any issues with applying the monokote to both sides of the gap? (top and bottom)

Ted

ReallyUglyStick

My Feedback: (5)

nope, no issues. it's just not needed on both sides, just one side will do. putting it on the bottom hides it. i've always done my gaps as illustrated above, accept that on the rudder i seal both sides so they look the same.

djlyon

I seal both sides to just keep the dirt out. Don't cover the wing flat surfaces and control flat surfaces until after installing the control surfaces, pinning the henges and sealing the gaps. Then it won't be unsightly.

crosswind

I found it to be worth while getting a roll of clear Monokote just for that purpose. Sealing hinge gaps, that is. I can use it on any other color and its invisible. Sealing those gaps, even if they aren't large, can make a BIG difference in response.

gelcoat-RCU

My Feedback: (206)

I had the gap problem on a few bought "second-hand" planes and here is the way I solved this hic. I used "clear silicone". Here's how:
Prepare next to you a tube of clear silicone, a rag of paper towel and one available index finger. Prepare the surfaces on each side of the gap by cleaning with paper towel and alcohol.

Now, fully extend the flying surface to one way or the other to the limit. Sperea a small fillet of this slick silicone stuff. Continue to hold the surface deflected and using this available index finger and the rag (or paper towel) in the other or resting somewhere next to you slide your finger along the gap being sealed removing most of the silicone. As you run your finger along wipe the excess removed on the rag...and continue on to the end of the gap. Now deflect the surface to the other extreme and run your finger again to level off the paper thin film being left in the gap. Leave to dry overnight...then early next morning go fly. The film does not in anyway impede the movement of the flying surface and will last a long time without peeling.

LDaba

My Feedback: (2)

Johnny Fuzz : Another reason to seal the control surface gap is that it will prevent air spilling through the gap. This leakage diminishes the effectiveness of the control surface. In short, (not that I am long winded ) , sealing the gap will increase the effectiveness of the surface. Less control input will be needed to achieve a given result.
To seal the gap you can also use a clear tape. Hobby Lobby offers this.
Happy landings, Tony.

robert

Yeah, theres special tape you can buy just for that. Its invisible, if you do a good job. Simply peal it back, and rub it on. Easy.

Kevins_RC

My Feedback: (1)

I normally accomplish sealing the gaps when covering the aircraft initially. I normally apply a narrow strip of covering to the leading edge of the control surface and the trailing edge of the wing, vertical & horizontal stab. I then cover the control surface with the desired color of covering, though I cut the covering oversized so that there is about an inch extra of material hanging over the leading edge on both sides (top and bottom) of the control surface. I then tape the excess covering material back with masking tape, and hinge (I usually use giant scale CA hinges (40-Size Fun-Flys)) the control surface. I then hold the control surface as far as it will go. Using a trim iron, I then seal the gap, both top and bottom. Then I cover the wing, vertical & horizontal stab so that this covering then covers up the flap used to seal the gap.
I like to seal both top and bottom. This keeps the fuel exhaust away from the CA hinges. Fuel and oil will deteriorate the CA hinges over time.
Hope that this helps!
Kevin

Scorpionjack

http://www.rcuniverse.com/showthread...84&forumid=107]

Capt Jim

My Feedback: (168)

Hinge gap sealing is a very good idea since it helps to prevent flutter which can take an airplane apart quite quickly. But also, be aware that sealing the hinge gap seems to increase the efficiency of the control surface, dramatically. I sealed the gaps on my old PT-40 trainer, which flew very nicely before sealing.(very small gaps and no flutter at all) After sealing...WOW, the difference was quite suprising. I actually had to reduce the control throws to get the plane back to where it was handling with the unsealed gaps. I sealed both top and bottom gaps, but I dont think doing both sides is neccessary. I cut long thin strips of monokote, (about 1/2 to 3/4 inch wide) just wide enough to fold it in the center along its length, and tuck it into the hinge gap, and just barely come up onto the actual control surface flat area. Its a bit of tedious work, but if you are careful about keeping the line straight it comes out looking good. I used a contrasting color for sealing, but using the same color would make it almost invisible.
Good luck with the project.

MinnFlyer

My Feedback: (4)

Capt Jim brings up a good point, he says "it seems to make them more efficient". Actually what's happening here is that if you have a gap, you control surfaces are "Less efficient" than they should be.

In the past, I never thought much about sealing gaps. I figured if the air was blowing over a surface that was deflected up it's going to push that surface down and little (if any) air will blow through the gap. What I hadn't considered was that at the same time the air was creating a high pressure area on one side of the gap, the other side of the surface is creating a low pressure area and literally sucking some of the airflow through.

So... Sealing the gaps WILL give you more efficient controls.