Side Booster Connectors / Couplers / Ejection / Separation Methods

[BigMacDaddy]

I am wondering what type of coupling / connection and ejection / separation methods people have used for side boosters -- basically a side booster that you put engines in and that you want to assist in launching the rocket but then separate from the main sustainer when the ejection charge goes off (I suppose with boosters having some type of recovery system as well).

I believe that I saw someone that did this with a Thunderbird SAM when I modeled it (mine were static). Ideally would find some examples in LPR but looking for ideas from any sources. Thunderbird put as an example but actually thinking about this for a different model initially.



I tried searching some in the forums but may not have figured out the correct search terms since I did not find much.

Thank you in advance for any ideas or past experience.

 

[Scott_650]

If you don’t want to rig your own with stand-offs, dowels and launch lugs there’s the kit from Apogee https://www.apogeerockets.com/Rocket-Kits/Skill-Level-2-Model-Rocket-Kits/Strap-on-Booster-Pods

 

[Charles_McG]

I've got a couple Titan IIIe threads here and on YORF. That model uses posts and lugs made from launch lugs and dowels, along with motor ejection (or -0 motor burnthru). What I came to realize is that I was separating the nosecone at MaxV - which is hard to manage.

My scale space shuttle threads here have a different approach: 3D printed rail guides and mini rail sections, spring loaded boosters to push away, with a fusible line holding the boosters in place and an altimeter controlled hot wire cutter to let them free. The idea was to cut the spent boosters loose to let them decelerate from drag and gravity before the motor ejection. I think I was using a Quantum. Accelerometer based launch detection, like a proton would work better. A shuttle stack doesn't fly fast - nor high - and there's a lot to cram into a short time.

 

[BigMacDaddy]

If you don’t want to rig your own with stand-offs, dowels and launch lugs there’s the kit from Apogee https://www.apogeerockets.com/Rocket-Kits/Skill-Level-2-Model-Rocket-Kits/Strap-on-Booster-Pods

Thank you -- that is great to see as an example. I was going to put my pegs the nosecone and the holes on the body but had a similar idea.

 

[BigMacDaddy]

I've got a couple Titan IIIe threads here on on YORF. That model uses posts and lugs made from launch lugs and dowels, along with motor ejection (or -0 motor burnthru). What I came to realize is that I was separating the nosecone at MaxV - which is hard to manage.

My scale space shuttle threads here have a different approach: 3D printed rail guides and mini rail sections, spring loaded boosters to push away, with a fusible line holding the boosters in place and an altimeter controlled hot wire cutter to let them free. The idea was to cut the spent boosters loose to let them decelerate from drag and gravity before the motor ejection. I think I was using a Quantum. Accelerometer based launch detection, like a proton would work better. A shuttle stack doesn't fly fast - nor high - and there's a lot to cram into a short time.

Thank you Charles - I will seek those threads out!

I was definitely thinking about speed at booster separation as well as the booster fouling up the sustainer's trajectory (i.e., if it did not separate quickly or smoothly enough)...

 

[Charles_McG]

YORF link, to a pic with the attachment posts.
https://www.oldrocketforum.com/showpost.php?p=197239&postcount=16

 

[BigMacDaddy]

If you don’t want to rig your own with stand-offs, dowels and launch lugs there’s the kit from Apogee https://www.apogeerockets.com/Rocket-Kits/Skill-Level-2-Model-Rocket-Kits/Strap-on-Booster-Pods

Why do they run those full length sticks down the boosters rather than just having a hook / pin in the bottom that interfaces with the main body bracket?

 

[Scott_650]

Why do they run those full length sticks down the boosters rather than just having a hook / pin in the bottom that interfaces with the main body bracket?

I’d say to keep the boosters square and aligned to the sustainer - probably not 100% necessary if you’re building your own rocket but if you’re selling a commercial kit you’d definitely want to minimize the buyer’s margin of error.

 

[BABAR]

speaking from experience with standard staging rockets with a chute on the booster (long gap with stable booster, so needed SOMETHING to keep booster from augering in), chutes deploying at high velocity are not optimal. easiest option is streamer or even nose blow. If you MUST use a chute, consider breaking the rules and wrapping the shock cord around the chute and using a long elastic shock cord, the wrapped chute should take some time to unfurl (during which often the booster if stable is STILL climbing) so the booster slows before the chute deploys.

 

[jqavins]

It might be a good candidate for break-apart recovery a la Estes Whack Wiggler, Odd'l's Break-Away, or some joker's "CATO recovery".

 

[Daddyisabar]

Look up PSR 18/24 on the forums and review sites. One 24mm core and four 18mm boosters. A Parallel Staged Rocket that was sold years ago on Ebay. Inter locking lower tabs and a simple launch lug hangar on top. I built and flew several times until 24mm core got too hibachied and then into the repair bin where it still is.. Always got a nice Korolev Cross and really high flights, well over 2K, on a D12 7 and four A8 3s, light that 5 motor cluster! Had to have a good ground support team to track and recover all five easy pieces. The tabs were a bit tricky to get interlocking properly after painting and it required fairly careful flight preparation. He also had a PSR 13/18 kit.

 

[BDB]

I basically knocked off the Apogee booster design last year. It worked pretty well. D12-0 engines in the boosters generated sufficient pressure to eject the nose cones and dislodge the boosters. The whole system was 3D printed.

https://www.thingiverse.com/thing:5484747