@JonathanwFL

I'm late to the party, but I'm thinking of a few high velocity rockets, and how it was done. That you are using double-base nitrocellulose smokeless powder rung a bell for me.

The Sprint ABM from project SAFEGUARD, had insane velocity, and went from "0" to Mach 10/7,600 mph in 5 seconds. Pulling 100 g's, and making plasma, which proved a challenge for its radio command link and guidance system.

They used a solid composite motor of a nitrocellulose and Zirconium flakes or "staples."

I know it was a while back, and you ran into a stumbling block with APCP, and being told .15 micron & smaller AP was regulated as an explosive, requiring a FEL, magazine, & all other regs.

Were you going to be trying an APCP motor, with HTBP binder/fuel? And the ultra-fine AP was necessary to get the needed Isp & thrust?

Within reason, it seems like getting hyper velocity for a KE only missile is more a total thrust issue than Isp. Although, exhaust velocity still has to be faster than the desired top speed.

To get more thrust, besides just making more exhaust, one can get higher density/heavier exhaust. So, I'm wondering if a composite motor using AP, and that makes additional thrust, compensating for not having the ultra-fine AP, with something dense/massive in the mix, like a metal?

Non-toxic would be best. And contributing energy as a fuel, would be best. And assuming it doesn't create runaway pressure curve issues & CATO. But, I'm wondering if metal that's just "there" if it doesn't contribute energy might increase thrust, just by being present in the exhaust stream.

I was thinking that Bismuth Trioxide could be a good candidate. There's literature on using it as a burn-rate moderator, it's an oxidizer, and replaced various lead compunds. Depending on the starting composition, adding Bi2O3 added 10% to total performance, while giving the desired burn moderating effects.

Like all this, getting the finest particle size for intimate contact is key. But if AP & polymer is on the menu again, maybe the Bismuth would make it workable without the ultra-fine AP. And, I don't know prices, but it is presumably 100% unregulated.

This guy in China... he's very scant on details, but... he seemed to accomplish something along the lines of your project, with an HTBP motor. It's unclear if the horizontal flight was an accident, but probably intentional to avoid notice, and losing the launch almost immediately on the low cloud deck.

If you watch his other videos, he's doing fuel & motor tests... in random spots wherever he could find sufficient privacy in China.

But, there is a brief shot in his other videos of the BEAUTIFUL motor. He claimed to use CNC to cut the star-profile core out. And there's also a picture of what appears to be a vibratory vaccum-casting rig he built.

Well... um,

Holy shit.  

Well... if it actually reached 9000fps +, if it's "welded" or not, isn't that kinda academic?

Because, I'm pretty sure it's going to be "welded" no matter what by that point. Because that's in excess of Mach 10, at like 60,000ft or something. At sea level, or just a few 100ft AGL most everywhere but maybe Denver or Nepal & Tibet... that's even higher.  

Shit's gonna GLOW. If it reached full potential, this is more like a shaped charge or EFP jet hitting something than a "rocket."

Not the "Swizzlestick" application, (well... maybe?) but I keep thinking about These... whenever I see them, and can't help but think that two of these stacked, converging & diverging, would make a damn dandy & cheap rocket nozzle, that's really really tough, and ain't going to erode.

At least for rockets in the nominal diameter & size and throat expansion ratios that it might plausibly work.

Either "glued" with some crazy high-temp zirconia adhesive something-r-other in a little kiln, or just stacked and held in compression by an outer sleeve of metal tubing crimped & formed that's holding them together with a few tons of force.

Wilson is the go to guy now.
@Wilson

Please hang on, I want to talk to somebody first.

why am I not surprised we have a "rocket Dr" as a member.

Here's a question, and sorry if it's out of context, I've read everything, in the thread, but I might not be getting everything or implied assumptions everyone else knows.

As to the Swizzlestick high velocity rockets, don't they have an ultra-long propellant grain of a unique conical cross-section that runs the entire length of the body tube?

So I'm confused about the talk of the carbon fiber engine body, unless this is a shorter different motor for some kind of initial proof of concept test. Or just discussing the motors from the M202 Flash reproduction as a comparison point?

And a tl/dr synopsis of what's below... Does the long skinny shape of a Swizzlestick, and it's (hopefully) extreme velocity, demand a certain rpm/spin, is that "higher" or "lower" than what one might expect? And does the conservation of angular momentum (centrifugal pseudo-force, etc.) complicate, or actually simplify any construction, joints, or fastening?

In broad terms st least, I'm following the discussion of screw loads, surface area & buckling, and the loss vs. gain ratio of fasteners. The weaknesses from the penetrations/holes, vs. their holding strength etc.

One question about buckling, or possibly magnification of unexpected or non-ideal off-axis loads etc. What's the rpm of the Swizzlestick going to be, and what is the rate increase or gain in rpm going to be from launch to max velocity?

With bullets, that's easier, you can just calculate MV against the twist, and acceleration/ time can effectively be ignored because that only happens in the barrel, and rpm decrease from aerodynamics in flight until impact are negligible. So that is just: MV x (12/twist rate) x 60 = RPM (US/Imperial anyway)

For a rocket with vanes in the exhaust to spin stabilize it, it would (probably?) be a lot slower than bullet rpm's. And (I'm guessing) be some sort of complex function of the exhaust velocity, it's density, the surface area of the vanes, their angle, the mass of the rocket, and maybe the rate gaining as combustion decreased the mass. Then all against the rocket diameter, and the moment arm for the torque the exhaust & vanes will be applying, etc.

All math wayyy beyond me.

And arguably, what Westinghouse did for the initial tests definitely "worked" so there's that. What I'm wondering is if the RPM of a Swizzlestick gets "high" inherently because of its mass-fraction, thrust & velocity, or because it "needs" it for stability, what are the implications?

Can it be over-stabilized and fight its trajectory, creating off-axis supersonic aerodynamic loads?

Could the conservation of angular momentum actually strengthen or weaken any joints & connections in the nose, body, & motor/nozzle, because they'd effectively switch from compression to tension, or vice-versa?

I think this might be treading on the math of stress vs load stiffness, and if, or when, you need to treat the load as actual rotation in the reference frame? Or like simple static or gravity loads?

Could the conservation of angular momentum combine or add to other loads? Like the outward rotation force on the rocket body adding to the outward combustion pressure of the motor? Or quickly magnify a bulge or crumple from on or off-axis forces in the flight direction?

Does the high SD of an arrow-like Swizzlestick (somewhat apples & oranges because of free flight ballistics vs. Powered... ) need an ideal rpm? In bullets & reloading, twist rates/rpm are mostly discussed against grain weight, and SD is kind of implied given the caliber, as higher gr weight & SD automatically implies a longer bullet.  

@JonathanwFL

Thanks for taking the time to explain.  

Thinking further, it makes sense that the internal nozzle vanes will put an upper cap on the rpm. As they'll only add torque while the rocket fires, and even really loooong fuel grains/cores will be over & done fast. .5 seconds probably.  

And no matter what the exhaust velocity & mass, and whatever the efficiency is, the 48" long Swizzlestick masses thousands of times more than a bullet, so that's a lot of inertia to get rolling.

Since this hobby is just for fun and it's not (even remotely) going head to head with any of our paying dealers.
And since I've ALWAYS LOVED rocketry from Estes to Century to ENERJECT to AREO-PACT and beyond!

Let's see how this goes,... just for a change from all of that dark stuff (like cancer, heart failure, floods, fire, etc).


Please don't expect too much.  I don't,.. but I am hoping for the best.




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