SideWinder (not the missile) Horizontal Spin Recovery Failure--Fixable

Working again on Horizontal Spin Recovery. Most of these birds completely separate the nose cone (comes down with a streamer) with the body and tail of the rocket spinning around the roll axis, automatically orients horizontal to direction of fall. Ejecting the nose moves the CG backward close to fin can. Not sure if the spin itself increases the drag, but the horizontal attitude of the rocket certainly increases the surface area (especially compared to ballistic recovery==== very bad) and slows the bird down on descent.

Wanted a ONE piece rocket, and wanted to go big. Also didn't like tracking two pieces.

Launch weight with D12-5 165 grams.

Arrow straight boost, not much weather cocking despite moderate winds.

This design has a tail piston, at ejection the charge fires and forces the piston (with the engine) backward, moves CG back to the fin can. I put vent holes to allow the ejection gases to vent laterally once the piston was all the way back. Forgot about inertia--- piston stop and vent holes were insufficient to keep the piston from ejecting itself completely out of the tail of the rocket. Unfortunately, with the piston ejected, the CG for the rest of the rocket moves FORWARD. Meaning Ballistic Recovery.



Nose cone recoverable (landed in soft dirt.) The tail ring (which is the really the hardest part to make) survived okay. The remaining body tubes (both outer and internal piston) are badly crimped (meaning they are now a source of future motor mounts!)

Next version will have an internal cable stop to keep the piston from sliding out. Will also need to attach that to a strong but removable bulkhead (removable to adjust cable, strong to force tube out back. May just attach to nose cone and tape the nose cone on from the outside. Will also use a longer boom to force the CG further back (ideally should be at center of fin can.)

Really cool idea. I had my big bertha fall sideways for almost the entire way down once because I rolled the chute too much, actually fell slower sideways than it falls in normal position with it's 12 inch chute.

I'd put the vent holes on the inner tube, and pretty close to the motor. That way it would start venting and the piston would stop accelerating much sooner, instead of accelerating for the full distance of travel and not venting until its going full speed, my theory at least. Also they wouldnt be visible in launch position, and so could be made bigger.

Interesting technique. You might also want to look at this:
https://www.info-central.org/?article=276

This is a detailed report about how long, thin rockets can be made to slide backwards and glide down. It does mention that a spinning rocket is more likely to glide, whereas a non-spinning rocket with the same CP/CG relationship might nosedive, though it does not explain why.

Damn! You just planted more seeds for rocket designs in my head. :wink: Shame on you! Now lets see.......