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tsatpalkar wrote:Hi guys,
I am a student from Waubonsie Valley who ordered the Pusher Twins 2018 kit. Our kit did not come with the Full sized drawing sheets, or any sheets used to measure and markup components. Is this supposed to happen? How can I get these sheets?

bjt4888 wrote:Regarding Reveur's question about building to the 3.0 gram minimum:

This type of "build to weight" analysis has been posted previously (Jeff Anderson posted a thorough version), but here's a version specific to this year's Freedom Flight helicopters:

This year's FF kit motor sticks are about 2.5 square inches of 1/16" sheet each. If you are using 5.5 cubic foot density wood, which is a 9.8 gram sheet of 3"x36" wood (if consistent overall, which it won't be), the motor sticks will weigh about 0.234 grams each. If you are using 4.5 cu ft density wood, which is a very rare 8.0 gram sheet of 3"x36" wood, the motor sticks will weigh 0.188 grams each. The lighter wood will therefore reduce the helicopter overall weight by 0.092 grams, which is a 2.6% reduction in airframe weight if you are assuming a 3.5 gram helicopter. Total flying weight, of course should consider the weight of the rubber motors.

When building to weight is challenging, every component, every stick of wood and other parts, should be evaluated in this manner.

Another example: the 3k carbon tow used to reinforce the motor sticks weighs approximately 0.0075 grams per inch; times 18" on each stick (9" each side), this totals 0.135 grams. The CA glue used to apply the tow can double the total weight, as constructed. Practice applying the carbon tow to scrap wood, weighing parts and final assembly to learn to minimize the amount of glue used. Glue, especially CA glue, is pretty heavy. Also, maybe compare constructed weight using different lighter glue, like Duco Cement. Test on scraps to see if you feel that the strength/weight balance is appropriate.

Good luck,
Brian T.
Academy of Model Aeronautics member off and on since 1968

tsatpalkar wrote:Hi guys,
I am a student from Waubonsie Valley who ordered the Pusher Twins 2018 kit. Our kit did not come with the Full sized drawing sheets, or any sheets used to measure and markup components. Is this supposed to happen? How can I get these sheets?

SluffAndRuff wrote:The instructions to not explicitly state this (as far as I saw), but many teams crumpled their mylar before placing it on the rotors. The pictures appear to do the same, but once again, I can't find this stated in the instructions. Is this the proper way of building it? Thanks!

SluffAndRuff wrote:The instructions to not explicitly state this (as far as I saw), but many teams crumpled their mylar before placing it on the rotors. The pictures appear to do the same, but once again, I can't find this stated in the instructions. Is this the proper way of building it? Thanks!