I recently picked up a bunch 13mm motors. This model would be a good way to burn through some black powder.
The Estes Time Warp has three BT-5s motor mount tubes (left side, in yellow) joined to a BT-55 (gray tube). A 55/50 adapter joins to a heavy walled BT-50 (unusual) and finally the gray nose cone.
Mentioned earlier, a heavy wall BT-50
The new self-adhesive Estes shock cord mount
A laser cut 3/32" thick balsa sheet
The four centering rings -
The pairs are laminated to make two thicker rings.
That small center triangle is very close with not much to hold it onto the assembly.
Cool. Grabbed one of these at their end-of-year sale, will be building it this year. Looking forward to this one.
ReplyDeleteHave been thinking about whether to add some sort of positive motor retention, most likely an M2 threaded rod in the center of the motor cluster with a nut and washer screwed on.
That's how I built my Rocketarium 13mm Trident - it works well though I did add a commensurate amount of nose weight.
DeleteHi Neil,
DeleteIt would have to be a very thin threaded rod. There should be enough open area for the M2, 2mmm rod.
If my math is right, the diameter of the included circle of three BT-5 tubes intersecting in tangent is 2.1375mm. So enough for M2 threaded rod with a little slop or a #2-56 imperial screw (2.184mm) if you grind the threads down a little.
DeleteActual water-slide decals. Two thumbs up, Estes!
ReplyDeleteSurprised at the heavy wall BT50 tube as well - I wonder if it's an availability thing rather than an engineering choice? It's probably the least critical tube in the whole rocket.
ReplyDeleteHi Openroad,
DeleteI don't know why the heavy wall tube was used. The nose cone and adapter seem to be made to fit the O.D. of a thicker tube. There is no noticeable "step" the the shoulder of the nose cone.