Finished —Gone Fission —- Big Time CATO recovery (by design)

[BABAR]

Okay. A little old and a little new.

Balsa is great, but it’s getting pricey and it’s a bit bit of work, especially when the sides are involved. Lot of lumbar.

It is kind of an upscale of the Mayday, but upscaled a bit. I just like the pun name “Gone Fission”

https://www.rocketryforum.com/threads/mayday-mayday-gone-fission.35512/
Problem with Mat Board, it gets a little flimsy.

Sooooooo

The big things are the side fin units

The little boards are cheaters.

The medium boards are stiffeners

 

[lakeroadster]

You spend a lot of time and effort on these awesome designs and builds. My suggestion: start using basswood, and toss in a bigger motor. Same performance, more durability, and only a bit more spendy.

 

[BABAR]

Cheaters glued in. These are looooong cheaters. Have to say though, using Mat board is easy way to make them, and they probably would work on balsa to paper body tube construction as well.

Might be useful especially for long winged birds like SR71 types.

 

[BABAR]

Cheaters on.

Need a term for the next piece. “guide”?

It serves to space/align the pieces together around the central motor mount.

The half moon cut out (dremel-Ed out, got a bit smoky in the room!) is to access the holes in the blade-fins.

The holes will be the rubber band ports that will hold this puppy’s hind end together on boost.

There will be a Nose-Pyramid (4-sides equivalent of nose cone) that will hold the forward ends together.

 

[BABAR]

Top pic.

BT-50 Body tube. Used an Estes tube marker to mark 4 equally spaced holes.

I fold the tube longitudinally to punch two holes, the fold it again 90 degrees.

The folding DOES weaken the tube, as do the holes. The tube is “resized” by reinserting a motor casing. This is removed and an engine block is placed just tailward of the holes, which will line up with the holes in the blade-fins.

Gets a bit risky here, especially with a zero delay motor which is purported to have a weaker blow through force than a true clay capped ejection charge.

Here the burn through needs to melt the burn bands (that’s a given, pretty much 100%. The rest of the force needs to push out the nose pyramid to release .

So I put a piston on the end of a dowel.

Hoping the blow through will be enough to blow the piston out even with the holes in the sides.

 

[BABAR]

Oh BTW, the Mylar tape at the tail is intentional, as it gives me a base for external tape wrap for motor retention.

Keeps it from peeling off paper and paint off when you REMOVE the tape wrap.

 

[BABAR]

Load ‘ER up.

 

[BABAR]

Fission is getting a bit complicated. Although it isn’t nuclear physics……then again…….

The upper section is the piston. The rear ring/plate/base is the activation plate, so blow through (“ejection “ is classic term, I’m keeping this because my understanding is it is weaker than classic ejection and I want to keep that in mind), anyhoo, blow through kicks piston forward hopefully at least to vents.

The forward centering ring also serves as a plunger or pusher for the streamers, four orange plastic streamers that will slow down the tube on descent, and are supposed to look like flames. I know, pretty cheesy.

The forward cuts in the body tube are the blow out vents. The length of the piston , location of forward pusher, and position of the vents is strategic. The vents are not exposed until the pusher clears the streamers out the front.

Once vents are exposed, the rubber bands are burned, the nose pyramid had released the forward ends of the blade-fins, so any decompression through vents should blast the blade-fins outward for max CATO effect.

I will have a shock cord if the plunger blows all the way out to keep the plunger attached to body. These come down on streamer and should impact on motor casing, so should be good there.

The blade fins should flutter/tumble recover.

 

[BABAR]

The wood skewers are to support the tube weakened by vent slots. @lakeroadster asks me do I plan these things up front? Obviously not, as had I thought it through I would four long supports crossing the vents AND holes, instead of two sets of four. Probably would use carbon fiber rods or long flat plates.

 

[BABAR]

Need to add shock cord attachment between piston and body tube, debating Painting.

now decision is do I drive 2.5 hours each way to fly it or just mail it to somebody to try.