Ejection Charge Back Pressure

[SteveA]

Here's the scenario, after horking-up a Quest Navaho fiddling with motor clip in the second stage, I kinda had an ah-ha moment. Rather than hoping that the clip clears the coupler during staging and separation, why not omit the clip and friction fit (think that's the right term) the motor into the tube? My question is, would this work? In those nano-seconds during the ejection of the recovery system, would the back pressure from the charge (if any) be negligible enough that the motor would not be blown out of the back of the rocket?

 

[Pantherjon]

Here's the scenario, after horking-up a Quest Navaho fiddling with motor clip in the second stage, I kinda had an ah-ha moment. Rather than hoping that the clip clears the coupler during staging and separation, why not omit the clip and friction fit (think that's the right term) the motor into the tube? My question is, would this work? In those nano-seconds during the ejection of the recovery system, would the back pressure from the charge (if any) be negligible enough that the motor would not be blown out of the back of the rocket?

Yes, I think it should work..There are quite a few 2 and 3 stage rockets where the sustainer motor is friction fitted..

 

[sylvie369]

If you're careful, and the dimensions allow it, you can run a wrap of tape around the sustainer motor and the sustainer motor mount tube to help keep it in place. Even if you don't do that, careful friction fitting will work. It's worth becoming experienced at figuring out how tight a fit is tight enough.

 

[SteveA]

It's worth becoming experienced at figuring out how tight a fit is tight enough.

I think I'll be getting my baptism of fire here soon. I built a Quest Zenith II and have omitted the clip and will go the tape around motor route. When launching weather ever arrives, I'll let you know how it worked out. Just in case, you may want to have 911 on speed dial and several gallons of Bactine on standby.

Thanks guys!

 

[WillMarchant]

You might also want to look into gap staging. The page at https://www.apogeerockets.com/Education/how_to_multi-stage.asp has some info. This makes it easy to accommodate a motor hook on the upper stage.