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Building Tips and technical articles. => Building techniques => Topic started by: Randy Ryan on May 11, 2010, 07:06:52 PM
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OK, can someone give me a hint as to how you lay the tape in the gap. I envision wrapping the tape over a long thin straightedge and carefully working into place.
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OK, can someone give me a hint as to how you lay the tape in the gap. I envision wrapping the tape over a long thin straightedge and carefully working into place.
I would also like to read a full explanation of the process, hopefully with pix.
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now from what I have read - you dont need to push the tape into the gap - just cover it - and also that you fully delfect the flap - fill the "V gap" with talculm powder - and tape over it - the blow the posder out from the other side. the powder stops the tape sticking along the control surface - which apparently can cause stiffer controls.
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now from what I have read - you dont need to push the tape into the gap - just cover it - and also that you fully delfect the flap - fill the "V gap" with talculm powder - and tape over it - the blow the posder out from the other side. the powder stops the tape sticking along the control surface - which apparently can cause stiffer controls.
Wow, that's interesting, I'd have never thought that.
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I use strips of manila folder, about 2" wide and same length as distance between hinges, plus about an extra inch on each end. Fold it in half lengthwise and make a sharp crease. Open it up, put sealing tape ,sticky side up, along length of crease. centered on the crease. Use another piece of tape at either end to tape it down on manila stock. Now fold the manila back over on the crease and it will also fold the tape with it and you will have a holder with the sealing tape on it. It helps with getting the tape down into the hinge line. After you get it position, use #11 hobby knife to cut sealing tape at either end from the pieces of tape holding it to the manila stock.
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Lets say you want to tape the elevator gap. Flip the plane over and deflect the elevator to the max 'up' position .... or deflected down toward the bench. I lay the tape on the stabilizer first, and then working from the center, roll the tape over onto the elevator. When you deflect the elevator back to neutral position, make sure the crease goes up into the gap. This will give full range of motion .... never tried the powder ... sounds like a good idea.
Larry
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I would also like to read a full explanation of the process, hopefully with pix.
http://stunthanger.com/smf/index.php?topic=11355.msg99963#msg99963
See post #9 by Brett Buck, complete with drawings. I am still using the Moore (Scapa) tape and wax-paper-on-the-flap method. Just taped some hinges this week.
Larry Fulwider
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Thanks Larry. I should have done a search first.
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Putting Windex on one surface makes it easier to get the tape down into the crack nicely. The tape slides on the Windex, but will begin to stick after you rub it for a few minutes.
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Whenever I felt the need for tapping my hinge joints I always did it with a hammer.
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See post #9 by Brett Buck, complete with drawings. I am still using the Moore (Scapa) tape and wax-paper-on-the-flap method. Just taped some hinges this week.
BTW, I now seal across the hinges on the flap. It very slightly improved the transition in the vertical 8 on both airplanes (the one I crashed in 2005 and the 2006 airplane I am flying now). I put grease over the hinge barrel to keep it from sticking. Paul Walker had a problem at the 2005 NATs that he traced to leaks around the hinge barrels so I just copied him. I only got 5 flights (well, 4.7 flights) with mine fixed before I crashed the airplane, but it fixed a bunch of tiny little issues that I had never been able to get rid of.
I can't overstate how important I think it is to get those hinge lines sealed. It it obviates so many potential trim issues for essentially no effort that I can't see any reason not to do it. Sealing up the little 1/32" gaps on either side of the hinges made more difference than changing to a different airfoil.
Brett
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I like the grease idea, I was going to tape them up snug to the hinges because of the stickieness. Maybe tonight.
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BTW, I now seal across the hinges on the flap.
Brett
But not on the elevator ?
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But not on the elevator ?
Just because I haven't gotten to it, next time I replace the seals I will. The flap is much more important to get perfect because the rolling moment possible from tiny differences in the leak from side to side is potentially so large. That's the big advantage of sealing the gaps- not so much that it makes the surfaces more effective (it does, quite a lot) but that it makes them *the same* from side to side over all amounts of control travel. Unsealed, no matter how good you are, it *will not* be the same from side to side, and it *will not* be the same over the entire control travel. Before I discovered the advantages, I spent hours trying to either set the hinges using feeler gauges, etc, or carefully sanding the point of the flap and elevator to get them *exactly the same*. It helped tremendously, but even with all that, as soon as I sealed the gap, all those little trim issues just went away.
Brett
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Has anybody taped surfaces covered in monokote? Did bad things happen while trying to remove the tape?
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I have taped the surfaces on my planes that are Monokoted, Ultracote, and painted. Have not had any problems with any of them. No need to remove the tape unless it gets to the point its falling off, and then, well,,,,, its falling off so no big deal
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Has anybody taped surfaces covered in monokote? Did bad things happen while trying to remove the tape?
Depends on what kind of seal material you use. When I did it with Fascal it was fine and then when I went to remove it, it left all the adhesive behind. Fortunately with Monokote you can use lacquer thinner to remove it, but it was a mess. With Scotch "Crystal Clear" or the Moore tape, it just pulls off with no issues. It's no different from how it works on painted airplanes.
Brett
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I may have missed a bit of detail in the various posts, but can't seem to get a clear indication from them so here is the question anyway:
Does one have to seal both the upper and lower surfaces or is it sufficient to do the lower only?
Methinks on the lower only would look much better.
I am in Australia, so we fly F2B, negating appearance points. Out of interest though, how do 'front rowers' in the US manage if both surfaces really need taping, or are these models so superior in fit and finish that taping is really not required?
Also exactly which 3M / Scotch product is the best for this application? I assume the common or garden variety Scotch Crystal Clear is not mylar and therefore less suitable. Brett can you advise the details of the mylar product?
Also I have an outboard tip trim tab, approx 50mm of hinge line separate to the flap. Should this be taped as well? H^^
Thanks,
Peter Anglberger
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The lower surface will suffice and won't keep you off the front row. The 3M tape was Scotch Crystal Clear. The name in the US changed to Scotch Multi-Task Tape. I don't think it's Mylar, but it works.
I would tape the tab, too.
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Out of interest though, how do 'front rowers' in the US manage if both surfaces really need taping, or are these models so superior in fit and finish that taping is really not required?
No one, repeat, no one, makes the gaps small enough that sealing them doesn't matter. Actually, the smaller you make the gap, the more critical it becomes to get them exactly the same on each side.
I don't think the Scotch "Crystal Clear" (or multi-task, or whatever it is called now) tape is mylar, and neither is the Moore tape. It's softer than Mylar, and I think mylar will be more prone to cracking after a while. The Scotch lasts essentially forever. If I said it was mylar I was lying!
Brett
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Brett's comment above that he now seals even across the hinges themselves (plastic barrel hinges) is a real eye-opener. I have been converted to a believer in Our Lady of the Blessed Hinge Tape and can see a big difference even at my modest level of ability. I believe Brett said before somewhere that unless you can build hinge gaps smaller than one air molecule you need hinge tape.
If you cannot get the Crystal Clear tape (much better and easier to use and replace than other clear tapes) send me a pm with your address in Oz and I will send you a roll of it. One roll is good for probably 50 models or 3 lifetimes, whichever comes first.
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I have to ask, doesn't the wet exhaust cause the tape to lift after a while?
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I have to ask, doesn't the wet exhaust cause the tape to lift after a while?
Well, there's no wet exhaust getting into the hinge lines on a piped airplane - reason enough to build one. But it handles oil pretty well.
Brett
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To Peter in Oz, turns out I do have the product identifier: 3M Scotch "Gloss Finish Multi-task Tape" 34-8507-5365-7. This should be the same Down Under, presumably, if it is shipped from the USA.
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we can get Scoth Crystal Clear in New Zealand (and Australia) from Warehouse Stationary - I will be off there tomorrow to get some more......
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Putting Windex on one surface makes it easier to get the tape down into the crack nicely. The tape slides on the Windex, but will begin to stick after you rub it for a few minutes.
On the whole, Howard's Windex method seems superior to the waxed paper method -- based on one set of elevator hinges, so far. The hinge tape wanted to glide over my alignment tape at first, but I had way too much Windex in the hinge.
I'll do the flaps tomorrow, and see how the Windex method works (for me) on the longer span. Perhaps I'm clumsier than average, but all techniques require some patience to get a smooth, even tape application -- my experience. Too slippery is less hassle than too grabby, my prejudice.
Larry Fulwider
Edit: Yes, less Windex works great. See pic of "makeready" below. The blue tape "dots" are 1/4" spacers to position the guide tape back from the hinge line. The blue tape spacers are removed, and the Crystal Clear (with the Windex help) abuts the guide tape as much by feel as by sight. This was especially helpful as the plane is a Tutor II with full, deep, flap hinge lines.
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Well, there's no wet exhaust getting into the hinge lines on a piped airplane - reason enough to build one. But it handles oil pretty well.
Brett
Does this mean I can get away with taping a side exhaust plane-at least for awhile?
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I tape all my planes, I dont as of yet fly piped airplanes. occasionally you will note that the tape will start to loose some grip, but mostly if you leave fuel or oil laying on it. now my electrics,, I have not seen any issues of stray electrons causing the tape to loosen,, yet,,
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Ha. I read this stuff and taped over the hinge barrels before the NW Regionals. That got me within a couple points of Brett. I wonder what else I can tape.
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I'm taping my beat up old Time Machine tonight. Sunday will be flight test day....
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I have been using the hinge tape for electric rc park fliers. It sticks good is light and can be removed fromany typecovering, at least I ,ve yet to have a problem with it. The oil doesnot seem to bother it, dubro makes it I believe. I tape right over the hinges with no increase in control effort. George
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Wow! That was easy! Thanks to Kent Tysor, who made an awesome video of him taping the hinges on his Strega and sent it to me. After I watched him do it on his plane, it only took me a few minutes to do mine. Now I just need some decent weather tomorrow to test it.
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Tested the plane with the taped surfaces today. I was hoping it would make the plane 100% better, but that didn't happen. Oddly enough, the place it helped it the most was...inverted flight. It did help some other places a bit, such as the last corner of the hourglass, and seemed to help make the second half of the square 8 a bit cleaner. I'll keep the tape on, and keep practicing....
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Yep, some times it takes time for things to show improvement. Glad your getting it trimmed. H^^
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After a ten flights with the tape, I took it off today, three flights into the days session, and flew six more flights without it. I don't know why, but on my plane taping the flaps and elevators removed some funnies, but added others that I have a real hard time describing, and had absolutely no clue how to trim out.
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After a ten flights with the tape, I took it off today, three flights into the days session, and flew six more flights without it. I don't know why, but on my plane taping the flaps and elevators removed some funnies, but added others that I have a real hard time describing, and had absolutely no clue how to trim out.
Steve --
Being analytical as you are, you won't stop there, right? Yours is the first documented case (from a reputable source) of hinge taping "causing" problems, far as I know. :( The controls are as free as before taping, correct?
Perhaps part of the issue is that you added tape to an already trimmed airplane. You might look at your pre-tape trim notes and see what, if any, little oddities or twists you added / modified / or adjusted in the original trimming that may not be needed now.
Please do a "follow-up" story so we can all learn.
Larry Fulwider
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Well, after the Nats I might play some more with it, I am just out of time to fool with it right now.
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Steve --
Being analytical as you are, you won't stop there, right? Yours is the first documented case (from a reputable source) of hinge taping "causing" problems, far as I know. :( The controls are as free as before taping, correct?
Perhaps part of the issue is that you added tape to an already trimmed airplane. You might look at your pre-tape trim notes and see what, if any, little oddities or twists you added / modified / or adjusted in the original trimming that may not be needed now.
Please do a "follow-up" story so we can all learn.
Larry Fulwider
Hi LArry,
Steve is (or at least once was) a near and dear friend. One thing I can say about Steve is that he is a LOT like th eold time greats n the game of golf. Miller barber (Mr. "X") comes to mind along with Lee Trevino. The both had HORRIBLE golf swings and became millionaires when it was hard to do so in golf. They just grooved a bad swing and repeated it.
Did I also say that Steve can be affected by another golf analogy? The one of PARALYSIS BY ANALYSIS??
Big Bear (and yes I am just kidding, but he IS an injunear) LL~
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Being analytical as you are, you won't stop there, right? Yours is the first documented case (from a reputable source) of hinge taping "causing" problems, far as I know. :( The controls are as free as before taping, correct?
Perhaps part of the issue is that you added tape to an already trimmed airplane. You might look at your pre-tape trim notes and see what, if any, little oddities or twists you added / modified / or adjusted in the original trimming that may not be needed now.
That would be my guess, as well.
Brett
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I'm not that analytical, and certainly not wise in the ways of aerodynamics. My plane had/has plenty of issues. It might be good by local contest standards, but poor to pathetic by Nats Open standards. The short version of the tape is that it somehow excited some natural frequency with the plane/lines system that resulted in spectacular yaw/roll coupling and tons of line whip. I'm sure it could be fixed, but the time isn't there and I would probably have to start at square one to retrim. The plane is due to be retired very soon, so I don't know if its worth the effort right now either.
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The plane is due to be retired very soon, so I don't know if its worth the effort right now either.
I think that the fact the plane is soon to be retired is a good reason to continue trimming/analyzing it as a test bed for future builds. The risk of making a fatal adjustment is much less than a ship all shiny and new. Kind of like having your kid learn to drive in an old beater rather than the new family ride.
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Is there any plane out there that does not need trimming no matter how old or how many flights it has. Going from one area of this great land to another brings in trim issues. I remember a local flier that says he is still trimming his plane and it is at least ten years old. Oh and he does fly it a lot. H^^