Chinook Chat!

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Unome
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Re: Chinook Chat!

Post by Unome »

Might as well preserve the images here for easier reference:
bjt4888 wrote: Image
Image
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Re: Chinook Chat!

Post by Ash123 »

Unome wrote:Might as well preserve the images here for easier reference:
bjt4888 wrote: Image
Image
Image

Ohhhhh ok I see. Thanks guys, that helps a bunch! I have one last question though- I’m having a little trouble getting 3k tow CF, but I can get a 3k tow Kevlar. Could that also work? If kevlar is less dense than CF, would it be better to use?
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Re: Chinook Chat!

Post by Rêveur »

Ash123 wrote:
Unome wrote:Might as well preserve the images here for easier reference:
bjt4888 wrote: Image
Image
Image

Ohhhhh ok I see. Thanks guys, that helps a bunch! I have one last question though- I’m having a little trouble getting 3k tow CF, but I can get a 3k tow Kevlar. Could that also work? If kevlar is less dense than CF, would it be better to use?
Ash, Kevlar would have excellent tensile strength, but would not be able to match the 3k CF in compressible strength. I wouldn't personally use the Kevlar, even though I believe the weights are similar.
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Re: Chinook Chat!

Post by Ash123 »

Rêveur wrote:
Ash123 wrote:
Unome wrote:Might as well preserve the images here for easier reference:

Ohhhhh ok I see. Thanks guys, that helps a bunch! I have one last question though- I’m having a little trouble getting 3k tow CF, but I can get a 3k tow Kevlar. Could that also work? If kevlar is less dense than CF, would it be better to use?
Ash, Kevlar would have excellent tensile strength, but would not be able to match the 3k CF in compressible strength. I wouldn't personally use the Kevlar, even though I believe the weights are similar.
Oh ok, gotcha. Thanks!
Also, would using carbon fiber reinforced spars help the helicopter if I’m already reinforcing the motor stick, or would that just be excess weight? And is there any thickness for the motorsticks that you would recommend? Also, how can I force my spars to develop a pitch? I’ve seen pitched rotors at competitions but I don’t know how to build them.

Sorry, I know I’m asking a lot of questions, I’m just trying to figure this all out.
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Re: Chinook Chat!

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Re: Chinook Chat!

Post by Ash123 »

Hey guys
Can someone explain how to build the rotors? I don’t understand how you can create a pitch if they are just two sticks. Also, what is the material used to cover them? Is it wax paper?
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Re: Chinook Chat!

Post by ScottMaurer19 »

Ash123 wrote:Hey guys
Can someone explain how to build the rotors? I don’t understand how you can create a pitch if they are just two sticks. Also, what is the material used to cover them? Is it wax paper?
Mylar is used to cover the rotors and the two main spars are offset vertically and radially then connected with ribs to create the pitch.
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Re: Chinook Chat!

Post by Ash123 »

ScottMaurer19 wrote:
Ash123 wrote:Hey guys
Can someone explain how to build the rotors? I don’t understand how you can create a pitch if they are just two sticks. Also, what is the material used to cover them? Is it wax paper?
Mylar is used to cover the rotors and the two main spars are offset vertically and radially then connected with ribs to create the pitch.
Oh Ok but what do you mean the spars are offset vertically and radially? As in, if they were on an xy plane,they are set apart a certain distance in the y direction And in the x direction?
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Re: Chinook Chat!

Post by bjt4888 »

Ash,

See Jeff Anderson’s post on page 7 of the “Helicopters C” thread in this wiki. He posted several links to standard helicopter plans. One of these plans should answer your question.

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Re: Chinook Chat!

Post by Ash123 »

bjt4888 wrote:Ash,

See Jeff Anderson’s post on page 7 of the “Helicopters C” thread in this wiki. He posted several links to standard helicopter plans. One of these plans should answer your question.

Brian T
Oh ok that definitely helps! One thing I still don’t understand though- How can the rotors be built so you can adjust their pitch? I can see how you could build them to twist around an axis, but how could you force them to lock into a desired pith and not unlock when they are spinning around in air?
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