Chris LaPanse

Great discussion....for the fin planform, there is the option to go with short fins with minimal sweep and as sharp a LE as you can make to reduce pressure wave. Think of an F-104 Starfighter wing or ...

Well, I just ran it through rocksim, and rocksim seems to think the total force would peak at ~220lbf (that's not too far from my value of ~72lbs on a single fin, considering all of the assumptions th...

New calculations: (these ones are right, I promise) New dynamic pressure: 86.4 PSINew lifting force on a single fin: 72.6lbsNew thickness required (ignoring flutter): 0.019 inches of top, aerospace gr...

On a related note - it's amazing how fast you forget things once you're out of school for the summer. Things like how to properly read the table in the back of the aerodynamics textbook. (apparently, ...

8 or 10 layers sounds like a bit much - you only need to build it up to roughly 1/8" plate. Anyone know how many layers there are in 1/8" plate CF?

That's why I mentioned starting with relatively thin plate, and then adding quite a few layers of T2T. That in essence makes the entire fin can one piece of CF, and that should allow for these kinds o...

Well, after some calculations, it appears that 0.083" fins are all that is needed at a minimum, at least for my design. That is using the assumption of a launch at 4k ASL (black rock, roughly), and th...

Well, my rough single stage sim to 40k or so with a 3kg rocket would pull around 50G on its way to M3.2. The acceleration shouldn't be a problem - Adrian's I powered shot did fine with greater acceler...

I believe that is accurate, though we only touched on supersonic flight in my Vehicle Design and Performance class last semester. Once school starts up again, I'll be taking 3000 level aerodynamics, a...

Well, I've put together some rough sims, and even with some fairly bad assumptions, I'm able to get some sims as high as 80k (with something like 40 seconds supersonic) on a 2-stage M3000 to J570, and...

They should definitely be within the mach cone, IMHO. Even if you assume a ridiculously short rocket (say, 1 foot longer than the casing), that allows for something like a 17 inch semi span before you...

It's not the weight for the sake of weight, it's the moment arm of having high density, high mass fins out far from the centerline trying to lever the fins off the body. Use low mass material - hell I...

I suspect that for this kind of rocket, drag is a larger problem than a few ounces - you'd probably get higher with solid carbon fiber fins made out of layers of uni aligned in different directions th...

That definitely sounds like the way to go, Adrian. A VK cone plus single thickness tubing would probably have a pretty significant gain compared to the double wall with a conical (though if I remember...

Honestly, I'd say CF should easily hold up if done right. I'm thinking of something like Jim Jarvis's LDRS 25 rocket (4" MD on an N4000), scaled down slightly. I'd be pretty surprised if you got too m...