I didn't see that coming...

[Pancho]

We recently had a large model rocket event in the desert, and it is a fairly large rc plane event as well. We went with our Civil Air Patrol and several other squadrons. We had an Aerospace Education portion on rc planes and had a buddy box setup.

One of our squadron planes is a Sky Hawk. This plane should almost fly itself. But a fairly seasoned cadet was having problems with it. It needed a couple control horns re-glued (which should have been my first clue). I get all the control surfaces working good and I take it up. It's flying great! I try some limited acro at about 200' and am about to hand it over to a cadet when we hear "WHACK!" It looks like it hit a gust of wind hit as it got really pushed around. I pulled off the throttle immediately. the wings then start to spin on the carbon spar! But, I actually still had a bit of control of it! Then the wings just blow completely off! The plane nose dives from 200'! It breaks off the nose, but amazingly, there is no other damage except a broken prop. Since it is a pusher...the nose is an easy fix. The crash was fantastic and we got quite a lot of cheers.

But seeing that the wings blew off, I inspected the plane, and nobody had done anything to secure the wings on...they were just pressed in. So, I decide to look at the rest of the planes, and we had a big glider, the Calypso, and it was having problems...wings weren't secured either. The cadets built these planes with some supervision (not me) and nobody thought to secure the wings because they said they were fairly snug when they put them on. But after some flight time...they loosened up and started moving around.

We got it fixed fairly quickly, along with tuning up the Calypso, and they were back flying, and flying really well.

So...lesson learned is do a complete inspection before every flight, especially on planes you didn't build.

 

[Craftydan]

Always good to do a preflight. Solid lesson to learn.

I do fly my calypso without tightening down the wing to the spar, but I've never had problems with it coming loose mid-flight. Ever. Even slightly. I've had times when a wingtip touches the ground on landing and it pulls out a bit -- if I were to launch immediately after the results would be less than satisfactory -- but having the wing loose enough to move on hard impact reduces damage.

As with anything, there's seldom a perfect solution -- leaving the wing friction fit will decrease damage on impact, but some wings can't hold together well, so you run a greater risk the wing will separate on it's own. A preflight decreases that and other risks significantly . . . but never all.

 

[Snarls]

When I first tried flying RC planes I had the Wildhawk which was recommended by Dave from RCPowers. Every time I took off, either hand launched or from a runway, the plane would do a sharp left bank and crash. I crashed multiple times from it, into the street and almost into some trees. It was not until a long time later after educating myself more from watching FT videos that I noticed that the wings would become askew during flight. They were pushed in tight with a friction fit before launch, but very quickly loosen in flight. After securing the wings with some toothpicks and velcro the plane flew great.

 

[Pancho]

Craftydan....our Calypso had a decent crash...broke the nose off. Probably loosened up the wings. They moved around very easy.

 

[Craftydan]

That's a pretty decent crash. Can't say mine hasn't had a spontaneous rhinoplasty, but the wing-mount cavities are still solid.

I suppose if mine were wallowed out a bit I'd pull out my screwdriver and crank down on the spar's clamps too. . . but I'd also be contemplating a replacement fuse. So far my abuse hasn't been anything gorilla glue, paint and a few carbon rods couldn't sort out.

 

[Theflyingfoam]

Hey not long ago I was a Flight Instructor for a civil air patrol course. Where was yours?

 

[Rc high flyer]

check your crap as flite test sayes