Estes screw-on retainers - check before flight!

[Sooner Boomer]

I think the Estes screw-on retainers are a great idea! I've added them to several rockets that didn't have them in the original design, plus I just built a Vapor which *does* use the retainer. the problem I've had with each and every one, is that they don't line up perfectly when you glue them in. This isn't a knock on Estes. The hole in the base has to be big enough to fit a variety of motor tube diameters, allowing the retainer to be easily be misaligned by just a *bit* - not enough to notice, but enough to prevent a motor from sliding in. I use some coarse sandpaper wrapped around a dowel, and smooth the obstructing bit away.

Check before you go to the range!

 

[dhbarr]

I think the Estes screw-on retainers are a great idea! I've added them to several rockets that didn't have them in the original design, plus I just built a Vapor which *does* use the retainer. the problem I've had with each and every one, is that they don't line up perfectly when you glue them in. This isn't a knock on Estes. The hole in the base has to be big enough to fit a variety of motor tube diameters, allowing the retainer to be easily be misaligned by just a *bit* - not enough to notice, but enough to prevent a motor from sliding in. I use some coarse sandpaper wrapped around a dowel, and smooth the obstructing bit away.

Check before you go to the range!

I slide an empty reload casing in for alignment during the build.

 

[DigBaddy]

I've noticed the 24mm retainer is a bit large for BT50 tube, but can be remedied by gluing a ring of BT50 around the outside of the tube as a shim first. Then, things line up and fit much better. Haven't seen that with the 29mm ones though.

Good idea to use an old motor/casing for alignment to be certain, will need to use that on the next build.

 

[dhbarr]

I've noticed the 24mm retainer is a bit large for BT50 tube, but can be remedied by gluing a ring of BT50 around the outside of the tube as a shim first. Then, things line up and fit much better. Haven't seen that with the 29mm ones though.

Good idea to use an old motor/casing for alignment to be certain, will need to use that on the next build.

Just be extra careful if you use a paper motor casing -- ask me how I know ^_^

 

[Tractionengines]

The Estes 24mm retainers are sized for # HBT-1000 (24mm motor mount tube. Ie. heavy wall). If used on the standard wall BT-50 (24.1mm with thinner wall) tube it is loose.

https://estesrockets.com/product/030463-hbt-bt-1000-engine-mount-24-mm/

 

[BEC]

@Tractionengines beat me to it.

There is no similar "issue" with the 29mm or 18mm retainers.

I really like using these and have put the 29mm retainer on my LOC Weasel and "park flyer" IRIS. I am using the 18mm one in several places instead of a motor hook. including recent Big Bertha builds my wife and I both did.

When I used a 24mm one on my Vagabond I believe I just built up the BT-50 motor tube with a bit of tape, or I used a piece of Semroc ST-9 tubing for the motor tube. I don't remember now.

 

[user 35280]

https://www.erockets.biz/semroc-body-tube-bt-50mf-metal-foil-8-long-1pk-sem-bt-50mf-8/
https://www.asp-rocketry.com/ecommerce/T-50H-Body-Tube-12-Long-.cfm?item_id=566&parent=13&navPanel=
https://locprecision.com/collection...cts/motor-mount-tubing?variant=39778656846015

 

[Sooner Boomer]

All three of the rockets I've put the screw-on retainers on have heavy wall tubes for motor mounts. They still had fitment/allignment issues. It's fully my fault for not checking everything *before* I got to the range. I've been trying to launch my Mega Rebel (it seems like) for forever. I finally got off the pad Saturday. I also see this as the solution to how to hold motors in on my "finless rocket" https://www.rocketryforum.com/threads/another-finless-rocket.131953/
I *think* I can retro-fit one onto the cone. If not, I can cut off the existing tail cone and make another (it's just card stock).