Building materials, covering

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kjhsscioly
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Re: Building materials, covering

Post by kjhsscioly » March 14th, 2011, 6:36 pm

Kovu wrote:Whenever we put mylar on it seems to not be as tight as it should be, any suggestions on how to make it tighter?
Have you ever seen a covering cradle? It is basically two parallel wood pieces held together by rods, and when the pieces are coated in vaseline, it can hold mylar down. Try covering in segments, especially toward the middle. I cover the furthest segment on the cradle, the pick it up and do one side of the middle segment, then the bottom and other side, then finally, the last segment. Also, having really clean hands helps, because the mylar won't stick on them. After you put it down, don't pull on the plastic, you will only warp the piece. Instead, gently pull it taut, to cut, or better yet burn the excess mylar off with a fine tipped soldering iron. Like chia said, wrinkling helps, because the minute wrinkles give it the stretch to prevent big wrinkles. just don't get concerned if it isn't pretty- a little give lets rotors catch more air on the way down.

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Re: Building materials, covering

Post by chia » March 14th, 2011, 8:20 pm

kjhsscioly wrote:
Kovu wrote:Whenever we put mylar on it seems to not be as tight as it should be, any suggestions on how to make it tighter?
Have you ever seen a covering cradle? It is basically two parallel wood pieces held together by rods, and when the pieces are coated in vaseline, it can hold mylar down. Try covering in segments, especially toward the middle. I cover the furthest segment on the cradle, the pick it up and do one side of the middle segment, then the bottom and other side, then finally, the last segment. Also, having really clean hands helps, because the mylar won't stick on them. After you put it down, don't pull on the plastic, you will only warp the piece. Instead, gently pull it taut, to cut, or better yet burn the excess mylar off with a fine tipped soldering iron. Like chia said, wrinkling helps, because the minute wrinkles give it the stretch to prevent big wrinkles. just don't get concerned if it isn't pretty- a little give lets rotors catch more air on the way down.
Thoug, as we figured out, it's a lot more awkward to use on a helicopter rotor (Well, if your rotors aren't flat).
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kjhsscioly
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Re: Building materials, covering

Post by kjhsscioly » March 14th, 2011, 11:30 pm

yeah, it takes some practice to cover, and comes with building a lot. I have found it easier to cover alone, though it seems couterintuitive, because you have complete control.

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Re: Building materials, covering

Post by sj » March 16th, 2011, 5:07 pm

One of my teammates father works in the plastics industry and said that he may be able to provide a low density, ultra-thin, nylon material for covering props. Does anyone see any significant advantages to this. Hopefully this material will be easier to work with compared to mylar.
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Re: Building materials, covering

Post by Frogger4907 » March 16th, 2011, 5:38 pm

sj wrote:One of my teammates father works in the plastics industry and said that he may be able to provide a low density, ultra-thin, nylon material for covering props. Does anyone see any significant advantages to this. Hopefully this material will be easier to work with compared to mylar.
The thinner it is the harder it is to work with. The Thinner it is the better it is for flight times.
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Re: Building materials, covering

Post by illusionist » March 16th, 2011, 5:44 pm

Does it make that much of a difference? I mean grocery bag vs. mylar vs. this ultra thin plastic...
It'll save you maybe .03 grams. Right?
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Re: Building materials, covering

Post by illusionist » March 16th, 2011, 6:01 pm

kjhsscioly wrote: I cover the furthest segment on the cradle, the pick it up and do one side of the middle segment, then the bottom and other side, then finally, the last segment.
So do you cover both sides of your rotor? Did you see a benefit from doing that? I think it might be more aerodynamic, i was just wondering if it would be worth it.
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Re: Building materials, covering

Post by chia » March 16th, 2011, 7:20 pm

No, kjhsscioly and I only cover one side, the surface that is facing upwards on the rotor, to the extent of my knowledge.
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Re: Building materials, covering

Post by kjhsscioly » March 16th, 2011, 9:23 pm

illusionist wrote:
kjhsscioly wrote: I cover the furthest segment on the cradle, the pick it up and do one side of the middle segment, then the bottom and other side, then finally, the last segment.
So do you cover both sides of your rotor? Did you see a benefit from doing that? I think it might be more aerodynamic, i was just wondering if it would be worth it.
Sorry, I should clarify. I see the helicopter blades as each side having three quadrilateral shapes, so when I say I cover on side, I mead one edge of the quadrilateral (the one on the spar), and then the bottom edge and last edge, and so on...when I said side, it was in a 2D sense. But, when we cover, one half of the rotor is covered on the top and the other on the bottom, because we cover the edge always moving into the air.

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Re: Building materials, covering

Post by Frogger4907 » March 28th, 2011, 12:18 pm

Kovu wrote:Whenever we put mylar on it seems to not be as tight as it should be, any suggestions on how to make it tighter?
Hold a lighter under it and slowly move it closer until it tightens, be careful too tight will rip your frame apart, or put a hole right threw the mylar.
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