MikeyDSlagle
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Add a boattail, that'll lower stability as well.
But then it wouldn't exactly be a true upacale.
But then it wouldn't exactly be a true upacale.
Soliciting opinions:
1. Rail buttons: 1010 should be enough for this, right? It's not like I'm sticking K motors in it... I'm thinking I'll use the Apogee-style rail buttons with weld nuts inside the tube, mostly because 1. I've used them before and 2. I like them. Conformal guides are cool, but you can't really replace them easily.
2. Beveling the fins... I'm thinking something like a 60 degree angle for the leading edge, 45 degree for the trailing edge.... Beyond "a sharp edge goes through the air better than a dull one", is there a particular formula/reason/place to learn on why I should go with a particular angle? And if I glass or carbon the fins, should I bevel them first and then clean them up after the reinforcement? Or just glass them then bevel them?
Thanks for any suggestions....
Soliciting opinions:
1. Rail buttons: 1010 should be enough for this, right? It's not like I'm sticking K motors in it... I'm thinking I'll use the Apogee-style rail buttons with weld nuts inside the tube, mostly because 1. I've used them before and 2. I like them. Conformal guides are cool, but you can't really replace them easily.
2. Beveling the fins... I'm thinking something like a 60 degree angle for the leading edge, 45 degree for the trailing edge.... Beyond "a sharp edge goes through the air better than a dull one", is there a particular formula/reason/place to learn on why I should go with a particular angle? And if I glass or carbon the fins, should I bevel them first and then clean them up after the reinforcement? Or just glass them then bevel them?
Thanks for any suggestions....
Awesome. 1010 is good enough for meMy rules of thumb: 1010 rail buttons are good for rockets up to 50 lbs. 1515 are good for rockets up to 200 lbs. As you approach the upper end of either range it's a good idea to make sure the rail has some support behind it.
I always bevel at 10 degrees and try to leave 0.030" thickness in the center. Bevel the main piece of G10 before you T2T. If you T2T the fins, I would trim the T2T material to either the back edge of the bevel or to the middle of the bevel. Then, coat the edge in epoxy to seal it.
That's what Dave at ARR said. I'm not certain, but I believe it helps keep it resistant to moisture.So does blue tube have to be sealed inside and out? Never even seen the stuff but have been thinking about trying it.
Current status is: hand sanding the BTs with some of that awesome 3m flexible sandpaper.
...Relatively speaking. I got a roll of 220 for $12 last year sometime and I am in zero danger of running out. One of the things that I love about it is how long it lasts: Normal paper sandpaper gets gummed up and you chuck it. This stuff you can rinse and wash and dry and it's good to go.I love that stuff, but it is crazy expensive.
...Relatively speaking. I got a roll of 220 for $12 last year sometime and I am in zero danger of running out. One of the things that I love about it is how long it lasts: Normal paper sandpaper gets gummed up and you chuck it. This stuff you can rinse and wash and dry and it's good to go.
Question for anyone following: Is too much stability a bad thing? According to my initial forays, this thing will have stability of 4-5 cal with a motor in it. Obviously, that means it's prone to weathercocking in a good wind, but other than that, is a super-stable rocket a bad thing?
Huh. That's a really interesting question. Just checked with OpenRocket and it was pretty straightforward to figure out. Stability is based upon the thickest tube. My rocket's biggest tubing is 54mm Blue Tube with an OD of 57.5mm. With an AT I motor, stability is 4.43 cal; CG at 949mm, CP at 1203mm. Delta is 254mm. 254/4.43 = 57.33, close enough to the max tube size. Wonder if the flight calculations "shortcut" to the biggest tube.On a rocket with transitions and different diameter airframes, which diameter does the simulation use to determine the correct cal to use for stability? If I have a rocket with 98mm, 54mm and 38 mm airframes connected with transitions, is 1 cal 98mm, 54mm or 38 mm? Or does it average the different diameters?
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