Extreme Speed Prop Planes Discuss the need for speed with fast prop planes (Screamin Demon, Diamond Dust, Shrikes or any REAL sound breakin'''' plane)

CA hinge failure D. Dust

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Old 11-02-2007, 07:02 PM
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freakingfast
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Default CA hinge failure D. Dust

The good news is, it’s not in the ground. The Diamond dust has between 250 to 300 aggressive flights on it and the covering is starting to look a bit ratty. I think the last straw was adding 30% to the YS 45 RE , it was the most improvement on any engine I’ve ever seen with more nitro. There were about 5 fights with this fuel but this time I took the dust real high and dove strait down. Just before impact I slammed the stick back and the twin HS 5955TG’s wasted no time moving the elevrons to 40 degrees . The air complained loudly and I hear the ooooohs from the guys behind me (yes, I’m a bit of a show off) but this time it pulled out lower than I like. About 6 feet rather than 20 or so. I thought it must be the extra speed or my reflexes are a bit off. The Dust seemed a bit mushy and I thought I heard buzz. Well, the tank was almost gone so I landed it. I always do a post-flight inspection to check the tightness of the linkage and that’s when I found the CA hinges at BOTH control horns were gone leaving only the elevron’s mid-span to wingtip hinges intact. The Ultracoat across the bottom of the gap was torn and on top it was completely pealed loose. I had even added an extra CA hinge next to the one the instructions called for near the horns. Guess they don’t last forever. Time to re-hinge and recover.

Real Lucky ….Again

PS, what’s the best CA hinge made?
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Old 11-02-2007, 08:41 PM
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Default RE: CA hinge failure D. Dust

I frown on the use of CA hinges for heavy service applications. Especially if they are not pinned.
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Old 11-02-2007, 09:11 PM
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Default RE: CA hinge failure D. Dust

Any hinge method can fail.....a lot depends on how it is executed. CA is not fuel proof, so I think the flaps should be hinged first, then cover the whole plane.....this way you end up with a totally sealed and fuel proof install in one fell swoop. The CA hinges should be no more than 4 inches apart on a fast plane, and toothpicked. Only ONE drop of thin CA per side, more CA makes the hinge material prone to cracking.
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Old 11-02-2007, 10:14 PM
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Default RE: CA hinge failure D. Dust

The hinges didn't pull out, just brocken like it was cut with a knife. They were totaly sealed with Ultracoat, one sheet bottom,one sheet top, tight in and out of the gap, in it's self a hinge. No Ca puddled,wiked or thickened at the point of flex. The CA hinges were closer than 4 inches,even two side by side at the horns (not doubled). Just a limit to what a piece of mylar can take.
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Old 11-02-2007, 11:25 PM
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Default RE: CA hinge failure D. Dust

I cracked some CA hinges when they first came out, but since then all has been well.
It sounds like you flex them quite a lot, 40 degrees is like a 3D throw, I don't think I've ever flown a fast delta with more than about 15 degrees!
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Old 11-02-2007, 11:44 PM
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Default RE: CA hinge failure D. Dust

You should try it, it's a hoot! Super fast rolls. Pull the stick quickly and the delta looks like it bounces of a wall . Most folk can't believe what they just seen. Fast, strong servos and battery are a must. Past about 40 degrees and the air just stalls and it's kinda lame.
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Old 11-02-2007, 11:58 PM
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Default RE: CA hinge failure D. Dust

I should add, if you run a 5 cell AA or 2/3C's you must reinforce the area where the battery is mounted or it may get shot out the bottom with high G's [X(]
1/16 balsa and Ultracoat don't cut it.
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Old 11-03-2007, 10:47 AM
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Default RE: CA hinge failure D. Dust

I have not had problems with the blue Radio South CA hinges but I have never made it past 150 flights. These deltas don't usually last that long.
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Old 11-03-2007, 11:49 AM
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Default RE: CA hinge failure D. Dust

I undersand what you say Mike. Things happen real fast at over a hundred. The RC gods have been on my side with this one. I've done my share of drilling holes in the ground LOL. Thanks for the tip and thanks for putting out good delta kits so others can enjoy!
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Old 11-03-2007, 11:50 AM
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Default RE: CA hinge failure D. Dust

I saw an ad years ago that talked about the various quality of different types of CA hinges. One of the things I like most about CA hinges is that I don't have to weaken the wood very much to install them, just cut a slit. After gluing, the wood should be back to normal as far as strength goes. The hinges that look the scariest to me are the ones where you just drill a hole, then push a barbed prong in.
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