Neutronium95
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- Joined
- Jan 17, 2010
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The fins were cut from a piece ot 1/8" T1100 plate from Rock West Composites that I had left over from a different project.Great flight. Hopefully I don't get too annoying asking folks this question here, but what was your max fin thickness? And more evidence that tip to tip is not a requirement for truly aggressive flights!
I know this gets away from the flying case intent but have you sim'd what a flight would look like if you fully enclosed the motor in a BT? A small weight penalty to avoid the leading edge damage to the fin can. I suspect you have another solution to the leading edge damage on the fin can but figured I'd ask the obvioussleevehaven't actually simmed a regular minimum diameter version of this design. My main goal with this rocket was never outright altitude performance, but to try out my ideas on a relatively small scale before attempting some higher performance records.
I'm getting Pathfinder ready to fly again this Saturday at FAR.
The fin can needed a bit of work. The leading edge damage was easy to fix with a hacksaw and a bit of sandpaper. I have ideas about getting a metal leading edge made, but I don't have the time or money to get it ready by Saturday. I think that it was mostly a structural issue, and that leaving it at two layers thick with a relatively blunt bevel on the top should be sufficient. The other thing that needed doing was sanding it to fit the motor case. Apparently the motor case that I used as a mandrel was a bit smaller in diameter than the motor case I used to fly at BALLS, and the one I have for this flight is even larger still. I spent a lot of time and effort sanding it to fit on the Playa, so I got a cylinder hone from Harbor Freight to speed up the work. It's not quite as loose of a fit as I'd like, but it fits much better now.
View attachment 615524
(please pay no attention to the bit of glue on the fin that I still haven't properly cleaned up....)
The big problem I faced at BALLS was recovery volume. I needed all of my weight to get the nosecone on, and didn't have space for a cable cutter. I've learned my lesson about being optimistic on recovery volume for future projects, but that doesn't really help me now. Ultimately I realized that what I thought was a 24" parachute was actually a 30" parachute, and I don't actually have a 24" thin mill parachute. So now I need to find or make a parachute in time for Saturday...
If there was a way to get aluminum tape to shear cleanly off I'd say go for it. But since aluminum tape isn't THAT sticky, and it's bonded directly to the motor case (which may or may not get a little bit hot) it would end up causing drag before it was useful. If it would fit, you'd wanna wrap the aluminum tape around the leading edge of the can, although that would make the step up from the case to the can alot more prominent and likely cause some parasitic Shockwaves to form along the leading edge (which is worse). I love aluminum tape so much, I just don't think you can yeet it to above mach 2 bonded directly to a motor and it still stick without mushrooming like the kevlar.You should get aluminum duct tape and one layer from the motor over the front edge of the fin can .
Although, when I'm able to get L2 this is why I'd love to be able to make a high Mach 2 test rocket to be able to test stuff out like this.If there was a way to get aluminum tape to shear cleanly off I'd say go for it. But since aluminum tape isn't THAT sticky, and it's bonded directly to the motor case (which may or may not get a little bit hot) it would end up causing drag before it was useful. If it would fit, you'd wanna wrap the aluminum tape around the leading edge of the can, although that would make the step up from the case to the can alot more prominent and likely cause some parasitic Shockwaves to form along the leading edge (which is worse). I love aluminum tape so much, I just don't think you can yeet it to above mach 2 bonded directly to a motor and it still stick without mushrooming like the kevlar.
I love aluminum tape so much, I just don't think you can yeet it to above mach 2 bonded directly to a motor and it still stick without mushrooming like the kevlar.
I approve of this ratio of flame length to rocket length.
Just a K2050.K-2050ST or research load?
"Just"Just a K2050.
Absolutely insane. Great jobJust a K2050.
The fin can is in almost perfect condition.What a beautiful liftoff photo, @Neutronium95 !
I can't tell for sure from the recovery photo but it looks like maybe the leading edge of the fin can fared better this time ?
Did you get any data from the electronics ?
Thanks for the report !
-- kjh
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