NCR kit question

I have an NCR kit that I built back in 1987 and have never flown it. I have lost all the info on what motors are used in it. The name of the kit is "The Orbit". Does anyone know what motor I would use? Thanks in advance.

 

[rstaff3]

F10-8, F25-9, F50-9, G25-10, G40-13, G80-13

Taken from EMRR's rec motors database.

 

[DynaSoar]

Originally posted by superdave
I have an NCR kit that I built back in 1987 and have never flown it. I have lost all the info on what motors are used in it. The name of the kit is "The Orbit". Does anyone know what motor I would use? Thanks in advance.

Weigh it, measure the diameter, and go to
https://ghiz.org/cgi-bin/rsim/rsim_form_ghiz.pl

Leave CD at 0.75
Put in your launch rod length
Leave stable speed = 25
Check the full flight profile box.

Then start picking motors from the list that you know you can get.

Look at the coast time (time until zero velocity) and pick the delay for that motor that comes closest.

Before you buy motors, measure the motor tube carefully. Some older models had what is now non-standard motor and motor tube diametersIf it's 29mm, you're fine. If it's 27mm, it's the older size, and you'll have to stick with 24mm motors.

F21 isn't on the suggested list because they didn't exist then. It's a 24mm motor close enough to the F25 that it'd work fine. Comparing with the suggested motors list, you'd want the F21-8. If the tube can handle it, the 29mm F20-7 would also do.

BTW, the 13 second delay Gs are no longer available. If you use a G with a 10 second delay, it might be going too fast at ejection. Use the simulator above to see what speed it's going 10 seconds after burnout.

 

[Rocketjunkie]

Originally posted by rstaff3
F10-8, F25-9, F50-9, G25-10, G40-13, G80-13

Taken from EMRR's rec motors database.

I used to have one. It goes very high. I'd start with an E30-7 or reload E18-7. Mine would even fly on a D12-3.