3D Printing Motor Mounts for 29mm Motors in Smaller Tubes

[frogglicker]

EDIT: There were a couple of minor issues with the STL. I have fixed them and it should be good now.
EDIT 2X: Issues with the print. See details in further print. STL redacted until the issues have been resolved. My apologies

I have been working on a collection of Motor Mount Tube assemblies for 18mm motors in smaller tube sizes. My son wants to run a 29mm in his Estes Olympus so I thought this would be a good time to expand the offering.

Below, are the 29mm versions. All use my standard 29mm retainer and should be sleeved with a 29mm motor tube to prevent deformation:

• BT-60
• BT-65
• BT-70
• BT-80

I am posting here first for two reasons:

1. I wanted to share this with the community before posting on Printables
2. Have some early adopters test and verify that these are usable.

I don't have all the body tubes in stock yet, so I can't test all of them. I tried to make the CRs just a little smaller than the published ID for the tube. For the motor tube itself, I referenced the LOC 29mm tube. The ID for the body tube was taken from the Estes measurements per OpenRocket.

Since the forward end of the MMT is flat (for easy printing), I usually extend the motor tube just beyond to get a fillet in there. The motor tube sleeve should be flush with the aft end of the MMT.

I just finished these, so I will print them out to make sure the retainers work and they fit the tubes I do have.

Have fun and enjoy. Let me know if there are any issues, so I can get them sorted.

 

[David Schwantz]

Do you have pics of the actual tubes? Thanks.

 

[frogglicker]

I'm printing now... will be a day or so. My printer's not as fast as some. I'll post them as soon as I have them. I can tell you that the 18mm versions turned out really nice and I have used them successfully in battle er... flight!

 

[frogglicker]

Oops. Imma

The first print just finished and it has some issues. The ID of the MMT is too small for the 29mm sleeve. It will fit a motor but not with a sleeve inside. Also, the retainer is not threading correctly. I was sure this was right but pobody's nerfect. Not sure what happened but I will work on it tonight and get it printed and updated here ASAP. In the meantime, I'm taking the STL down. I don't want you to waste your time until it's done.

My apologies for the goof-up.

 

[frogglicker]

Ok, I got all the issues sorted out. Here's a picture of the updated file. I made some modifications and some additions:

• Fixed the retainer.
• Fixed the MMT ID so a motor tube sleeve can be used
• Fixed the BT-60 so the customized retaining cap OD is smaller than the body tube OD (just) - Now you can jam a BT-80 into your Der Red Max - NOTE: This cap has a smaller OD than the other one but will work on all of the threaded rings
• Added the MMT without the retaining ring
• Added the same Retaining ring, just separately. You can attach this to your BT sleeve.

Please let me know if you have any issues or if you find these useful.