Strap-On Booster Hardware Suite (BT-70 and BT-50)

This is a suite of five pieces of hardware you can print to allow a rocketeer to add strap-on boosters to their rocket for parallel staging that will drop away in flight similar to what you see with the professional rockets such as the European Ariane 5, the US Space Shuttle, the Japanese H2, H2A, and H2B, and the Russian Soyuz.

The models are designed for the Estes BT-70 (sustainer) and BT-50 (booster) airframe tubing. These models are small and detailed enough that you will probably want to print these on a resin printer. Or you can scale them up for larger rockets and print them with a filament printer.

The follow pieces are as follows:
1) Offset nose cone modeled after the Ariane 5 nose cone SRBs (not to scale),
2) Symmetrical nose cone modeled after the Delta II and III GEM SRBs (not to scale),
3) Nose cone end cap with a 3mm hole for a screw eye,
4) Sustainer upper mount
5) Sustainer base mount version 1 or version 2,
6) Booster base mount version 1 or version 2
7) Simulated Delta II and III GEM SRB nozzles for static display.

The parallel-staged boosters should use Estes booster motors with a delay of zero - A8-0, B6-0, C6-0 as examples. When the parallel stages are affixed to the sustainer the slot you create for the sustainer mount to fit in should be able to have the nose cone slide over it inside. When the booster motors burn they will eject the nose cone and recovery system while it is falling away from the sustainer.

Note #1: The triangles on the upper and lower sustainer mounts as well as the low booster mount are there to help align them accurately on the airframe tubes.

Note# 2: Not shown in any of the photos, there should be a piece of balsa or basswood glued to the area on the booster stage that sits right behind and next to the upper sustainer mount to keep the booster from moving forward.

Videos of parallel staging.
https://www.youtube.com/watch?v=0FEUffhvFuc

https://www.youtube.com/watch?v=N5p-stllS1g
https://www.youtube.com/watch?v=9Iphs9uDQbc