lmml 14/32
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Joined: Tue Jan 30, 2001 2:27 am

R/C Aircraft Flying (question For LAPA)

Thu Dec 27, 2001 3:49 am

Lapa: If you see this I have yet another question for you - Can you exceed the structural limit of a model and break it up in mid air?
 
FordLover
Posts: 189
Joined: Wed Sep 26, 2001 3:12 am

RE: R/C Aircraft Flying (question For LAPA)

Thu Dec 27, 2001 4:14 am

I'm not Lapa, but I do have an answer for you. Of course you can, and I have, with utterly spectacular results. I had the center joint (over the fuselage) of a foam winged sailplane give out in a pull-out after a dive. The wing folded up and down it came. It became a submarine shortly thereafter (landed in a farm pond). I wrote it off to a poorly assembled joint (my first attempt at building). After that (with a new wing), no problems.
 
lmml 14/32
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Joined: Tue Jan 30, 2001 2:27 am

RE: R/C Aircraft Flying (question For LAPA)

Thu Dec 27, 2001 5:37 am

Is there any indication on the radio that you are out of the envelope?
 
lapa_saab340
Posts: 391
Joined: Tue Aug 07, 2001 8:42 pm

RE: R/C Aircraft Flying (question For LAPA)

Thu Dec 27, 2001 6:56 am

Hi! Looks like Fordlover beat me to it  Smile There's really no indication you can have of how close the airplane is to tearing itself to pieces except for your own common sense or anything you can see visually. I think the scenario Fordlover gave you is a rather common form of structural failure hehe, It's happened to me too. I was teaching a friend how to fly with his trainer, I let him get into a dive too steep and I pulled too hard when I tried to save it, so the wing split at the middle. The model was one of those ARF (Almost ready to fly) types, and a plywood brace was the only thing holding those two wing halves together. I suppose it should be strong enough to withstand a strong pull-up, so maybe it was poorly built, I don't know.

Unless you get yourself in this sort of predicament, I don't think you need to worry too much about exceeding the structural limits of your model. If you're flying saiplanes, then you probably need to be a bit more careful about diving too fast and yanking that thing, since the wings are long and slender. But if you have an aerobatic plane you can probably toss that thing all over the sky without it coming apart!


 
lmml 14/32
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Joined: Tue Jan 30, 2001 2:27 am

RE: R/C Aircraft Flying (question For LAPA)

Fri Dec 28, 2001 1:36 am

Hello again LAPA, and thanks for the useful info, as always. I checked the local club and was told that they do not do buddy box instruction. I was told to go out and buy my model and transmitter and someone will give me lessons on my unit. I am a bit sceptical of this arrangement. What do you think?
Last weekend there was this Blue Angels F-18 turbofan with retractable gear and flaps. I was so impressed by the sound of that engine and the guy's flying. There was also a NASA F-15 but it started to rain as he powered up and the flight was cancelled.
 
lapa_saab340
Posts: 391
Joined: Tue Aug 07, 2001 8:42 pm

RE: R/C Aircraft Flying (question For LAPA)

Fri Dec 28, 2001 12:50 pm

Hello again LMML!
You can learn to fly without the buddy box arrangement too. Basically your instructor will take off and get the plane trimmed at a safe altitude, and then he will hand you the transmitter. He will stay very close to you so he can take over the controls should you get in trouble. The drawback of using this method is that it takes longer for the instructor to take control of the airplane. The buddy box is more convenient since no time is wasted when the instructor needs to take control. My friend taught me without using a buddy box, and it worked just fine (Although I'll admit I was nervous at first, knowing that if I got into a tight fix I would have to hand over the radio to my friend!)

Wow, was that F-18 powered by a gas turbine? I've never seen one of those flying myself! Last year I was down at this field in Florida, and this guy had a ducted fan F-16 and Blue Angels F-18. They're really something to see fly! But they don't sound very realistic if they're powered by a 2-cycle engine hehe. Hopefully those gas turbines will come down in price as time goes by.
 
lmml 14/32
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Joined: Tue Jan 30, 2001 2:27 am

RE: R/C Aircraft Flying (question For LAPA)

Sat Dec 29, 2001 5:58 am

Lapa: Re-the F-18 I don't know what sort of engine/s he had but it sounded very very real and so did the aircraft in flight. When it landed he parked it 5 ft away from me and there was heat coming off the exhaust pipes like a real plane.
You mentioned trimming the plane in flight. No this is new to me. Do models have trim tabs too?
 
lapa_saab340
Posts: 391
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RE: R/C Aircraft Flying (question For LAPA)

Sun Dec 30, 2001 1:35 am

LMML: Sounds like it had a gas turbine then!  Smile Ducted fans powered by two cycle engines don't sound anything like a jet - more like an overreving motorcycle!

Models don't have trim tabs. The radio transmitter, however, has a small trim wheel for each channel(throttle, rudder, elevator, and aileron). Trimming is accomplished by moving the entire control surface the necessary amount by using the trim wheel for the appropriate channel.

For example:
Say your plane is slightly nose heavy, and you find yourself having to hold back stick pressure in order to mantain level flight. If you move the elevator trim a bit, the servo will apply a bit of up elevator and leave it there while the stick is still in the neutral position. It works exactly the same way as the trim control in computer joysticks.

Btw, do you know if that F-18 had brakes? They probably need an arresting gear to stop that thing!
 
lmml 14/32
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Joined: Tue Jan 30, 2001 2:27 am

RE: R/C Aircraft Flying (question For LAPA)

Sun Dec 30, 2001 7:10 am

Is the trim wheel a basic feature on radios or does it come only on the expensive ones? Re-the jet F-18 I am not sure if it had brakes. The landing speed was a bit higher than the others. I only saw it land once so I cannot say for sure. I will pay more attention next time.
 
lapa_saab340
Posts: 391
Joined: Tue Aug 07, 2001 8:42 pm

RE: R/C Aircraft Flying (question For LAPA)

Sun Dec 30, 2001 4:57 pm

All radios come with a trim wheel for each channel (unless you buy one of those very cheap toy r/c cars, some of those don't have trim!).

If you buy a six channel radio, the 4 'main' channels (throttle, rudder, elevator, aileron) have trim, while the two 'auxiliary' channels for gear/flap do not.

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