Zioly wrote:Sensei_Sushi wrote:teoescana-543210 wrote:Hello!
I was wondering what would be more beneficial to add to our rocket in order to increase it's height when fired.
PVC pipe or LED casing?
Simple triangular fins or traditional rocket ones?
Thank you!
For backsliders (the rods that protrude from the top of the bottle rocket), lighter is usually better so PVC may not work as well as lighter materials. As far as fins go, the optimal shape really depends on the design of your rocket, testing multiple times with different wing shapes will allow you to determine the best wing design.
I completely agree with Sushi here. I've tested over 10 fin material and shape combinations, and I still haven't found the perfect one! The only way to do well at this event is to test, test, test!
One good material to use, is a garage sale sign... I know that they come from different materials, but you can find some that are kinda like plastic cardboard, which are hollow in the middle. These are really light, and strong, and if you cut them parallel to the "folds" then you can create a streamlined front edge. Also, just to reduce weight, My partner and I got 0.007 (or maybe 0.07 I don't remember) plastic film from an art shop, which you can then cut the back of your completely plastic cardboard fin off, and replace it with plastic film. Sure, it makes the rocket a bit flimsy, but it really trades off for the weight. Make sure to keep the leading edge of the fin strong with a strong material to make the fin sturdy. Also, recently we have gotten small carbon fiber dowels, and have taped/glued them to the top of the fin, so you can extend the fin farther down, making so you can use 0.002 inch film (which is really flimsy) without the fin getting flimsy. What I am getting at, is you basically make a frame for your fin out of carbon fiber dowels, and plastic cardboard, and then just cut a piece of thin plastic film to fill in the inside. Just as an FYI, the 0.002 film fins were 2 grams lighter than the 0.007 inch film fins, even with carbon fiber dowels, and larger surface area.
Problems are better pursued with General Electric GE90-115 engines.
2016 Nats:
Road Scholar:4th
Bottle Rockets: 9th
Meteorology: 11th
Gliders: 21st
(other events: Green Gen, Crime Busters, Helicopters, Hovercraft, Air trajectory)
Former Cheesehead