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InfiniCuber
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Re: Design

Post by InfiniCuber »

bernard wrote:
InfiniCuber wrote:
bernard wrote:Our team is almost done with our plane.anyone have recommendations for starting to test the plane? In Elastic Launched Glider last year we started with just letting the glider glide easily without launching it. Is there a similar approach people use with Wright Stuff to make sure the plane n't break on the first test?
I would suggest that you first try tossing it lightly with the propeller on (no rubber) and if it seems to glide well, put some rubber on and some trim flights, many times I have done 30 turns with a 15:1 winder (it may depend on the thickness of your rubber, but really only if it is SUPER thin or thick). That should help you trim a bit, then go with higher winds, trim. Etc!
Thanks for your suggestion! Could you explain what you mean by trim?
Sure! Trim simply means to change or adjust different aspects of your plane to make it fly better. Usually these aren't big changes, but they are enough to cause change in the flight. For example, if you have a detachable wing where your wing posts attach to the fuselage, you can lift one post up a little or down a little to have a different angle of attack or incidence. Another thing you could do to trim would be if you had an adjustable tail boom, like having a tough yet malleable piano wire (short piece) going from the end of the motor stick to you tail boom. Then you could change the angle of the horizontal stabilizer up, down, left, or right which could help with turning or lift, etc.
Hope this helps!
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bernard
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Re: Design

Post by bernard »

InfiniCuber wrote:Sure! Trim simply means to change or adjust different aspects of your plane to make it fly better. Usually these aren't big changes, but they are enough to cause change in the flight. For example, if you have a detachable wing where your wing posts attach to the fuselage, you can lift one post up a little or down a little to have a different angle of attack or incidence. Another thing you couldto trim would be if you had an adjustable tail boom, like having a tough yet malleable piano wire (short piece) going from the end of the motor stick to you tail boom. Then you could change the angle of the horizontal stabilizer up, down, left, or right which could help with turning or lift, etc.
Hope this helps!
Thank you so much! Your reply is really helpful.
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Re: Design

Post by TC-SciOly »

Does anyone know why might a Freedom Flight model plane fly for less than thirty seconds? We built everything according to the instructions, but both planes don't climb and both have flight times under thirty seconds. We aren't very experienced, but we are eager to learn. Any advice would be appreciated!
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Re: Design

Post by DoctaDave »

There could be a lot of things that are affecting your flight times, but it would help to diagnose your problems if you gave some information about your planes. Do you know how many winds you are putting into the motor? Have you played around with the incidence to make sure you're getting enough lift? Have you weighed your plane to make sure it isn't too heavy?
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Re: Design

Post by TC-SciOly »

We usually put 40 winds on 15:1 winder for our 0.094 rubber bands. First plane weighs about 8.4 grams and the second one weighs about 8.2 grams. We've changed a lot of variables (one at a time of course) on the planes and sometimes times improve, but never over 30 seconds. The one that weighs about 8.2 grams always plunges downwards after we release it :(
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Re: Design

Post by DoctaDave »

You should be putting at least 1500 turns into your motors, maybe 1200 if its too much torque with the .094 rubber. That would be about 100 winds on your 15:1 winder. Also remember to lube them, otherwise they will snap.
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Re: Design

Post by DoctaDave »

Also check the wash in on the left wing. If there isn't any, that could cause the plane to plunge as you described it and it is often the most overlooked cause of bad flights by new fliers. I remember I had that same issue with my plane, and it would dive straight into the floor after banking, but after I fixed the wash in I was getting flights of close to 2 minutes with minimal trimming.
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Re: Design

Post by TC-SciOly »

Thank you, DoctaDave. We'll try these changes right away. Also, what exactly does a "wash in" look like on the wing? Is this the same as a wing warp. If so, I THINK the models are designed to have that.
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Re: Design

Post by DoctaDave »

Wash in is the same as wing warp, and you should have about 1/8 of an inch to 1/16 of an inch of that, but your plane could require a little more, so try playing around with that. You will need more wing warp with more torque, so gradually go up in the number of winds you put into the rubber, and when it seems like your plane begins to plunge again try dewinding the rubber for a few turns to decrease the torque without sacrificing too many winds. You may need to dewind anywhere from 5-20 winds on your winder.
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Re: Design

Post by bernard »

How close should our team go to the 2 gram limit for them motor? I've heard some recommendations of making a 1.95 gram motor. How likely is it for a balance to measure it as more than 2 grams at the competition due to error?
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