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Parachute material
Posted: March 5th, 2022, 6:47 am
by ccasediaz
We are consistently getting flights above 20 seconds with ceiling height of about 33ft but want to get above 30. We are using the thinnest painter plastic now for our parachutes but have seen teams with some type of plastic that seems lighter and can get flights into 40 second range. Anyone know what plastic is best ???
Re: Parachute material
Posted: March 5th, 2022, 3:08 pm
by CookiePie1
ccasediaz wrote: ↑March 5th, 2022, 6:47 am
We are consistently getting flights above 20 seconds with ceiling height of about 33ft but want to get above 30. We are using the thinnest painter plastic now for our parachutes but have seen teams with some type of plastic that seems lighter and can get flights into 40 second range. Anyone know what plastic is best ???
The last time i did this event (before covid), we used these super thin trash bags that our school used for the classrooms and they worked really well. Maybe also consider using dry cleaning bags or something else. You'll also be able to increase your times by optimizing the ratio of parachute radius to string length for the weight of the ping pong balls you're using.
Re: Parachute material
Posted: March 5th, 2022, 5:31 pm
by knightmoves
CookiePie1 wrote: ↑March 5th, 2022, 3:08 pm
ccasediaz wrote: ↑March 5th, 2022, 6:47 am
We are consistently getting flights above 20 seconds with ceiling height of about 33ft but want to get above 30. We are using the thinnest painter plastic now for our parachutes but have seen teams with some type of plastic that seems lighter and can get flights into 40 second range. Anyone know what plastic is best ???
The last time i did this event (before covid), we used these super thin trash bags that our school used for the classrooms and they worked really well. Maybe also consider using dry cleaning bags or something else. You'll also be able to increase your times by optimizing the ratio of parachute radius to string length for the weight of the ping pong balls you're using.
People also have luck with grocery store produce bags - those are pretty light.
Re: Parachute material
Posted: March 5th, 2022, 8:08 pm
by jgrischow1
CookiePie1 wrote: ↑March 5th, 2022, 3:08 pmYou'll also be able to increase your times by optimizing the ratio of parachute radius to string length for the weight of the ping pong balls you're using.
Can you elaborate on this? Seems like when our kids go bigger with the parachute, there comes a point where it is just too heavy (no matter how thin it is) and it starts drooping. Is there a particular "formula" for matching parachute size to shroud line length to ping pong ball weight or is it just trial and error?
Re: Parachute material
Posted: March 6th, 2022, 6:59 am
by CookiePie1
jgrischow1 wrote: ↑March 5th, 2022, 8:08 pm
CookiePie1 wrote: ↑March 5th, 2022, 3:08 pmYou'll also be able to increase your times by optimizing the ratio of parachute radius to string length for the weight of the ping pong balls you're using.
Can you elaborate on this? Seems like when our kids go bigger with the parachute, there comes a point where it is just too heavy (no matter how thin it is) and it starts drooping. Is there a particular "formula" for matching parachute size to shroud line length to ping pong ball weight or is it just trial and error?
Yeah, it was pretty much just trail and error. The problem you've described is correct; you don't want the self-weight of the parachute to be so large that it doesn't fully "inflate".
Re: Parachute material
Posted: April 1st, 2022, 5:14 pm
by builderguy135
ccasediaz wrote: ↑March 5th, 2022, 6:47 am
We are consistently getting flights above 20 seconds with ceiling height of about 33ft but want to get above 30. We are using the thinnest painter plastic now for our parachutes but have seen teams with some type of plastic that seems lighter and can get flights into 40 second range. Anyone know what plastic is best ???
Two mylar sheets connected together with 3M Super 77 spray glue. Use 16 strings of sewing thread; this achieves >2s/ft.