Flight Troubles?

shorti96
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Flight Troubles?

Postby shorti96 » August 31st, 2009, 4:49 pm

Hey guys, I just can't seem to get the hang of building and flying my model airplane. I've tried all of the great ideas you have but can't seem to get it just right. Usually my planes just go straight for about 2 seconds and then they crash on the ground. I've also tried adjusting the area in which I fly my planes. can anybody help me PLEASE!!! ;)
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GitItWright
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Re: Flight Troubles?

Postby GitItWright » August 31st, 2009, 5:18 pm

OK. There is a lot to look at here. First, give me the basic dimensions of motorstick.. length, and cross section dimensions. Second, How much does it weigh? Third, what crooss section size is the motor you are using?

When you launch does the airplane ever climb? Does it ever fly level? Does it fly better on half the power? Answer those and we can proceed.

Good Luck
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shorti96
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Re: Flight Troubles?

Postby shorti96 » August 31st, 2009, 5:23 pm

Well first of all I haven't actually started building a new one for 2010 yet but all of the ones I've ever built have done the same thing and I don't know where to get started this year.

The planes never really started climbing but they did stay level for a few seconds but only twice ever.

If you can help me get started that would be great :mrgreen:
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andrewwski
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Re: Flight Troubles?

Postby andrewwski » August 31st, 2009, 6:47 pm

There's a lot that it could be. Without further information, it could be almost anything.

First, have you tried adjusting the position of the wing on the motorstick? This can often be a problem if your wing is too far forward or too far back. If you can afford the weight of a wing saddle, it can be very helpful for your first plane, as it allows you to figure out what different positions of the wing will do to the flight of the plane.

Have you attempted to change the angle of attack on the wing (how high the front is in relation to the back)?

If the flight is stable, i.e. a gentle glide, your motor may not have enough torque, however if it dives, then something isn't trimmed correctly.

Too much torque would also be a problem if it's causing the motor stick to bend.

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Re: Flight Troubles?

Postby jander14indoor » September 1st, 2009, 3:40 am

First, don't worry about this year or last years rules, problems and solutions are the same. Its still a rubber powered duration plane.

If you haven't flown more than a few seconds we really need to start with the basics and need to know more than it crashes in two seconds.

What design plane have you built and tried to fly? Was it a kit, which one. A design off the internet, which one. Own design, please give a detailed description. This is critical because you may be trying to fly something that just won't work and anything we say won't help.

Once we know your design, we need to know more about the execution. How well built, weight, "straight", center of gravity, control settings, etc. Those have to be close to right to get even a good design flying.

From there we'll need to know something about winding technique, rubber, etc. But frankly I don't see those as the problem, you should be able to get a good slow glide if the above is correct even with bad rubber or poor winding.

Jeff Anderson
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shorti96
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Re: Flight Troubles?

Postby shorti96 » September 1st, 2009, 1:52 pm

okay thanks when I start building I can't get you all some more info but right now, my school hasn't even started to meet for sci oly but we probably will soon so I'll post more info then thanks :D
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Re: Flight Troubles?

Postby Cyrus_D » September 7th, 2009, 7:13 pm

Currently I don't have a problem but a friend of mine usually does. He builds a 14+ cm wings with mylar, and half of the test flights he fly's stall. Is this a reason because of it is getting too much lift? Or is there maybe some other explanation.

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Re: Flight Troubles?

Postby jander14indoor » September 8th, 2009, 5:07 am

No such thing as too much lift, but it can come at the wrong time.

To interpret the stall, we'll need to know a little more about it.

Does it only occur at the beginning of the flight and only when he/she starts really adding on the winds? If so, you have a poweer stall, probably need to add some down thrust to the prop. Sometimes lowering the rear edge of the stab helps, but try that second if the rest of the flight is OK.

Does it occur repeatedly thoughout the flight? If so, your CG is probably too far back. These wide wings seem to like a more forward CG than the narrow ones, relative to chord.

Does it occur only after the haflway point in the flight? Possibly to rearward of CG, though not much, or possibly too much up elevator, try lowering the rear edge of the stab in very small increments.

Does it only occur after bumping into things? This ones trickier, your stability margin is too low and you'll need to change things in combination. Move the cg forward slightly and the tail back.

Jeff Anderson
Livonia, MI

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blue cobra
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Re: Flight Troubles?

Postby blue cobra » September 20th, 2009, 7:27 am

I propose this thread be used for any people who need help with their individual flights. Then we don't end up with 50 of these :lol:
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shorti96
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Re: Flight Troubles?

Postby shorti96 » October 19th, 2009, 12:26 pm

ok then, any way so can anyone tell me exactly what to do or post some designs that actually work??? because there's some designs on th web,but so far none of them have ever worked and I have to start building tommorrow!!! :o
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