Stormbringer 1, Interplanetary Defense Missile with Atmospheric Boosters

[stormbringergrey]

Showing off my scratch build from the 90's. 29mm central motor mount with 18mm motors in the pods. I reverse engineered the design in OpenRocket and started a thread in Plans. Video of a spectacular failure and a successful level 1 cert are available.

 

[BABAR]

nice! The transition is a great touch. I wonder, did you have do anything internally to protect it from the ejection charge? It looks narrower than a 29mm tube.

 

[stormbringergrey]

nice! The transition is a great touch. I wonder, did you have do anything internally to protect it from the ejection charge? It looks narrower than a 29mm tube.

The central body tube is a double walled 29mm centered in 38mm so the exposed tube at the booster attachment point is 38mm transitioning to 98mm for the main propulsion unit aft and the payload bay fore... so it's a simple straight path for the ejection charge and didn't require any special precautions. The boosters, on the other hand, had very small space for the 18" drogue shoots and had to be packed tightly.

 

[BABAR]

The central body tube is a double walled 29mm centered in 38mm so the exposed tube at the booster attachment point is 38mm transitioning to 98mm for the main propulsion unit aft and the payload bay fore... so it's a simple straight path for the ejection charge and didn't require any special precautions. The boosters, on the other hand, had very small space for the 18" drogue shoots and had to be packed tightly.

Ahhh. I didn’t appreciate the scale.

Looks like boosters are permanently attached. Does the whole structure require two more chutes? If not, booster eject or boooster nose blow, streamer, or venting would be options.

Still, would be a pretty sight to see that returning with three full canopies.

 

[BABAR]

Looks like boat tails on the boosters. Another option would be replacing the 18mm mounts with 13 mm mounts, go rear eject (take the tail cone with the eject pod). I am guessing the boosters are for show anyway , not required for safe velocity off the rail. You’d be surprised how much space you pick up on rear eject for laundry by down scaling the central tube.

I guess it is critical the main deploys before the boosters. Otherwise would be most….. entertaining. Unless the boosters are released from main frame, they look permanent in pics.

 

[stormbringergrey]

The boosters are permanently attached and yes, they are there for show. The boosters are not essential for flight, indeed I got my level 1 cert by flying on just a central H-180W by sealing the boosters with tape (the flight is my avatar picture). If anything, the honest truth is that the boosters are potentially detrimental as 3xE's will lift the rocket off an 8' rod even if the central motor doesn't light (or worse, is sputtering). I must be lucky, because with the exception of a very "interesting" first flight, I never had a failure of the central motor. I did have a few flights where one or more of the outboards failed to light but no negative steering tendency was observed. I will admit, there were a few flights where I swear the central motor didn't "kick" up to full thrust until midway up the rod. So why do it? Because it looked really, really cool... particularly at twilight with 3 blue points of flame around the central white plume of smoke.

As for recovery, same deal... I put 'chutes into the boosters only because I had nowhere else to vent the ejection charge and figured, why not? A 6 second delay on the central and 7 second delay on the boosters choreographed well, the drogue 'chutes would deploy about a second after the main but would inflate first so it was all happening at minimal velocity.