First Open Rocket attempt

[Jeff Curtis]

I just created my first Open Rocket file for the Bad Boy Rocketry clone of the Estes Impulse. I fiddled with the fins but think I have them close. The weight came out to 22 oz when the actual weight was 14 oz. The weight for the nose cone was off. I selected the Estes 2.5 nose cone but had to shorten it an inch.

Anyway, you can look it over and point out any mistakes I may have made I would appreciate it.

 

[neil_w]

Mostly looks good. I see a few small things to comment on:
1) That nose cone is showing as "filled", giving it a weight of 15 oz and that is what's throwing everything off. This appears to be an error in the parts library; I will file an issue on that and we'll get it fixed. In the meantime, if you uncheck "filled" and set the wall thickness to something reasonable, it'll get the mass a lot closer to correct (most likely it will then *under* estimate the mass, which is more typical in real-world use).
2) The material for your fin fillets is listed as "cardboard". Pretty sure that's wrong. Not extremely important other than estimating weight. On the other hand, typical fillet materials (i.e. epoxy) are not given as material options there, so I can't tell you what to choose for maximum realism.
3) Your motor blocks are located in front of the motor mount tubes, floating in the air. Easiest way to do stuff like that is position them relative to *top* of parent component, and then offset = 0, and they'll be right in the correct place.
4) Your shock cord is listed as 48" long by 2mm wide, which seems like an error for a 37" rocket weighing almost a pound. Doesn't make a big different to the overall model.

 

[Jeff Curtis]

Excellent. I did mean to measure the shock cord and correct that. I really appreciate the help. Fixing the nose cone brought the weight way down.