So, I have this very little bit of information that I am trying to translate -- well, understand.
Friction Forces in Launch Tube:
Tests run with 1-1/4" PVC pipe with an inner diameter of 1.38 inch showed a running friction of 1400 grams.
With a 1.62 ID Acetate shipping tube, the running friction was 200 grams. Adding in the vehicle weight, the
force required to balance weight and friction varies between 10 and 20 Newtons. This means that without breech
pressure, no motor with an initial thrust less than 20 Newtons would even move the vehicle.
So if I have a BT-58 based model with an OD of 1.540 inches, how do I calculate the optimal ID of an acetate launch tube?
I'm building this to be as robust (and light) as possible.
Best estimates currently put the model at +/-51 inches and 12 oz to 14 oz.
I'm hypothesizing that you want running friction at as close to zero as possible?
Thoughts?
Thanks!
Friction Forces in Launch Tube:
Tests run with 1-1/4" PVC pipe with an inner diameter of 1.38 inch showed a running friction of 1400 grams.
With a 1.62 ID Acetate shipping tube, the running friction was 200 grams. Adding in the vehicle weight, the
force required to balance weight and friction varies between 10 and 20 Newtons. This means that without breech
pressure, no motor with an initial thrust less than 20 Newtons would even move the vehicle.
So if I have a BT-58 based model with an OD of 1.540 inches, how do I calculate the optimal ID of an acetate launch tube?
I'm building this to be as robust (and light) as possible.
Best estimates currently put the model at +/-51 inches and 12 oz to 14 oz.
I'm hypothesizing that you want running friction at as close to zero as possible?
Thoughts?
Thanks!