NCR Motor Retainer

[sr205347d]

I bought a North Coast Rocketry Phantom 4000 off a guy who bought it off a guy . . .

Cool rocket, never flown.



But it is missing its motor retainer. (29mm) It looks like some kind of ring that you insert, twist and lock.



Are replacements available anywhere? If I had an STL file, I could 3D print one.

 

[Art Upton]

Next question, will a 29mm motor fit in it? Newer Estes NCRs had 28mm MMT.

 

[sr205347d]

Next question, will a 29mm motor fit in it? Older NCRs had 28mm MMT.

It is tight, but yeah -- with the label peeled off the motor.

 

[n3tjm]

RMS 29/40-120 will fit in it.

 

[Buzzard]

I have one that appears to have never been used. Compared it to the one in the bagged parts from an unbuilt Phantom 4000 and it is the same. I had built an original kit back in the '80s. Worked for NCR after retiring from the Air Force.

Drop me your address: crussell51 at hotmail dot com

Member of CSAR in Columbus 1968-1975. Hilliard HS Class of 1969.

Chas

 

[sr205347d]

I have one that appears to have never been used. Compared it to the one in the bagged parts from an unbuilt Phantom 4000 and it is the same. I had built an original kit back in the '80s. Worked for NCR after retiring from the Air Force.

Drop me your address: crussell51 at hotmail dot com

Member of CSAR in Columbus 1968-1975. Hilliard HS Class of 1969.

Chas

email sent. Thanks!

 

[Buzzard]

Sorry sr, but I have not received your e-mail yet and it did not show up in my spam folder.

Chas

 

[sr205347d]

Sorry sr, but I have not received your e-mail yet and it did not show up in my spam folder.

Chas

DM sent.

 

[jmasterj]

Could you just friction fit your motors?

 

[Troy3003]

I may have one laying around too if you don’t have any luck. The old SU motors were really tight, even pulling off the label. I built mine with wood glue back in the day and recently managed to remove the fins and CR’s and installed a 29mmt.

 

[sr205347d]

I may have one laying around too if you don’t have any luck. The old SU motors were really tight, even pulling off the label. I built mine with wood glue back in the day and recently managed to remove the fins and CR’s and installed a 29mmt.

Thank you so much, but Chas is sending me one.

TRF is the greatest!

 

[rcktnut]

The retainer doesn't work with all/ most motors. I used threaded tap inserts/ blind nuts and screen clips to solve the problem.

 

[sr205347d]

Chas,

Got your package. Thanks! And thanks for the parachute too.

The retainer doesn't seem very robust, so I may try to duplicate it with my 3D printer.

As it is though, I have one spent motor casing that fits in the tube, tightly. My SU G80 measures a tad larger with my caliper, and doesn't fit at all.

RMS 29/40-120 will fit in it.

I may have to go this way if I want to fly this bird.

Or else, if an Estes F-15 would fit, I could add some strap-on booster motor pods to the outside to help it off the pad. I did that with my Star Orbiter.

 

[rcktnut]

All the 29mm HPR Dr. Rockets/ Aerotech cases fit in mine (Big Brute). I built mine with the supplied MMT not knowing at the time that it was a tad smaller than 29mm. Your Phantom would fly great with H motors.

 

[tlainhart]

The retainer doesn't work with all/ most motors. I used threaded tap inserts/ blind nuts and screen clips to solve the problem.

View attachment 629200

I've got three NCR by Estes rockets that I built back in the day using Aerotech motor tubes to use both Darkstars and Aerotech SU motors.

You're right that the stock retainer won't fit around the retention ring of an Aerotech SU motor, but you can Dremel out some of the inner circumference of the stock retainer to get a fit, and it won't compromise the retaining properties.

 

[sr205347d]

Well, a 29mm reload case wouldn't fit, but an Estes 24mm adapter would. So I added two external motor mount tubes, and launched with three E12-4s. Even with three, it is still a tad slow off the pad, but it worked!