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Old 03-14-2016, 09:47 AM
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kevinj kevinj is offline
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So for a point of comparison, S8E/P (RC rocket gliders with 1.1 meter minimum wingspan) models flown in FAI spacemodeling competitions are usually at or below 300g in mass.

We routinely fly on Aerotech E6 reload motors. These motors burn for 7 seconds, have a peak thrust of just under 12N and an average of 5.27N. I've flown them to 800-1200 ft.

They are slotted, end burning APCP motors, and because they are reloads and not single use motors, cost about $6 per flight on average.

kj

Quote:
Originally Posted by wjwj
Really, epoxy? Isn't epoxy flame-resistant?

Your post got me thinking, so I did some theoretical physics calculations. Here is what I know:

The rocket plane is expected to weigh no more than 300g. According to the aforementioned site, the 7sec sucrose rocket produces an average thrush of 2lbf, or 9N.

If the plane weighs 300g, its weight is 3N. Therefore, the net force of the rocket is 6N upwards.

The acceleration at that weight and thrust is 20m/s^2, or 2G. Plenty for a rocket plane, since a rocket plane, by definition, is controllable!

This calculation reassures me that if I can mimic the end-burner sugar rocket, my rocket plane has a shot at working.

(P.S. - if the rocket plane accelerates for 7sec, it would reach speeds of >300mph without air resistance. Of course, air resistance will greatly limit my speed, but still cool!)
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