Xrain
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*New Update on 2nd page!*
I have started work on my Level 3 Certification Rocket. Me and 3 other flyers are attempting our level 3 certs on April 11th at Lake Louise up here in Alaska.
Launch Site:
We have a 25,000' waiver with a few 2 hour windows up to 50,000' if needed. The lake is about 20,000 feet x 30,000 feet, pretty much flat, and clear of obstructions. It is a pretty fantastic launch site.
Basic Rocket Design:
The basis of my rocket is a Wildman Extreme Kit, with the main modification I am making being the addition of an aluminum fin can that I am machining myself.
Fincan:
I am going with an aluminum fin can for several reasons. First and foremost I want to move on to bigger faster rockets eventually, and this gives me a chance to practice methods to fabricate precision fin cans. Next my rocket will be landing on a frozen lake. If it lands in a spot with poor snow cover the ice is about as hard as concrete, making fin breakages common problems. So I am eliminating that issue on this rocket with the aluminum. Next my rocket sims to about mach 1.5 with a AT M1500G reload. I don't want to have anything to do with fin flutter and aluminum is pretty good in that respect. Lastly machining my fin can should let me get my tolerances to at least a thousands of an inch, so the GoPro on my rocket should get some nice footage. There is a slight concern about potential stresses in the aluminum from when it was manufactured warping the can when I machine off a majority of the metal. That issue I cant really do anything about until I make the can and see how large of an issue it will be. It might just be a slight shift of a few thousands, or it might be a pretty significant twist.
I have mostly been making the fixtures to hold the piece of aluminum to properly machine it in the mill. Oddly making your fixtures tends to take up majority of the overall machine time when you are fabricating something. I should have these fixtures completed tomorrow.
My fincan is based off the Binder Design 4" MaxQ Aerospace Fin Can https://binderdesign.com/store/page13.html
Main design difference is my can is being machined from a 4" ID x 5" OD x 12" long piece of 6061 aluminum, vs. the bent sheet metal method that this can normally uses.
Here is a schematic of one of the 3 clamping pieces that will be cut out of that aluminum tubing. One of the more significant issues is I didn't read the fine print on McMaster well enough when I ordered that aluminum.
The length tolerances they provide is 1" So I the the piece I got from them is actually is around 11.4" long vs. the 12" that I was thinking I would get. Thankfully however, the aluminum is still long enough for the fin can but it does cut down on the amount that I can bevel the leading edge of the can.
I am going the more difficult route of machining the can, since my Sheet metal bending skills leave a bit to be desired. Additionally I can better scale this method to larger diameters, and still retain relatively tight tolerances.
The fins I have purchased from Mike at Binder Design. I just got them in today and they look pretty fantastic.
My wildman kit is still in the mail, I'm expecting it to get here in the next few days.
Thanks!
I have started work on my Level 3 Certification Rocket. Me and 3 other flyers are attempting our level 3 certs on April 11th at Lake Louise up here in Alaska.
Launch Site:
We have a 25,000' waiver with a few 2 hour windows up to 50,000' if needed. The lake is about 20,000 feet x 30,000 feet, pretty much flat, and clear of obstructions. It is a pretty fantastic launch site.
Basic Rocket Design:
The basis of my rocket is a Wildman Extreme Kit, with the main modification I am making being the addition of an aluminum fin can that I am machining myself.
Fincan:
I am going with an aluminum fin can for several reasons. First and foremost I want to move on to bigger faster rockets eventually, and this gives me a chance to practice methods to fabricate precision fin cans. Next my rocket will be landing on a frozen lake. If it lands in a spot with poor snow cover the ice is about as hard as concrete, making fin breakages common problems. So I am eliminating that issue on this rocket with the aluminum. Next my rocket sims to about mach 1.5 with a AT M1500G reload. I don't want to have anything to do with fin flutter and aluminum is pretty good in that respect. Lastly machining my fin can should let me get my tolerances to at least a thousands of an inch, so the GoPro on my rocket should get some nice footage. There is a slight concern about potential stresses in the aluminum from when it was manufactured warping the can when I machine off a majority of the metal. That issue I cant really do anything about until I make the can and see how large of an issue it will be. It might just be a slight shift of a few thousands, or it might be a pretty significant twist.
I have mostly been making the fixtures to hold the piece of aluminum to properly machine it in the mill. Oddly making your fixtures tends to take up majority of the overall machine time when you are fabricating something. I should have these fixtures completed tomorrow.
My fincan is based off the Binder Design 4" MaxQ Aerospace Fin Can https://binderdesign.com/store/page13.html
Main design difference is my can is being machined from a 4" ID x 5" OD x 12" long piece of 6061 aluminum, vs. the bent sheet metal method that this can normally uses.
Here is a schematic of one of the 3 clamping pieces that will be cut out of that aluminum tubing. One of the more significant issues is I didn't read the fine print on McMaster well enough when I ordered that aluminum.
The length tolerances they provide is 1" So I the the piece I got from them is actually is around 11.4" long vs. the 12" that I was thinking I would get. Thankfully however, the aluminum is still long enough for the fin can but it does cut down on the amount that I can bevel the leading edge of the can.
I am going the more difficult route of machining the can, since my Sheet metal bending skills leave a bit to be desired. Additionally I can better scale this method to larger diameters, and still retain relatively tight tolerances.
The fins I have purchased from Mike at Binder Design. I just got them in today and they look pretty fantastic.
My wildman kit is still in the mail, I'm expecting it to get here in the next few days.
Thanks!
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