Alex - Post #28 "By doing it that away it may break Argoina's 50,000' waiver and that cannot happen."
Lots of dead space in your design, are you trying to break the alt record or really break it? Cause I doubt anything under 50K will stick for long. Put the NC right on top of the motor and come fly with us at blackrock!
Also, those are some monster fins! 5.875 spans on a 4in MD....
Alex
Andrew,
I understand you are close to Argonia but is going to a site with a higher wavier not an option for you?
Its already an expensive hobby. If I used my money to drive to Black Rock to fly I would not have any money to actually get the motor and build the rocket. Someday I will but until that point Argonia is the place for me. But if you want to pay for me to drive out there I will. Its like a 1200 mile trip for me and my truck and trailer get 9mpg.
Good luck with your project, we just flew a 4" MD at Airfest with a similarly massive fin span (6") for the same reason, to keep it well under the waiver
What motor was that? All Composite? How many layers of reinforcement?
Its already an expensive hobby. If I used my money to drive to Black Rock to fly I would not have any money to actually get the motor and build the rocket. Someday I will but until that point Argonia is the place for me. But if you want to pay for me to drive out there I will. Its like a 1200 mile trip for me and my truck and trailer get 9mpg.
Haha, tell Mat more about the cost to drive to Black Rock, I'm sure he's eager to hear (we just got back from Black Rock, he drove 1900 miles each way towing a UHaul).
Good luck with your project, we just flew a 4" MD at Airfest with a similarly massive fin span (6") for the same reason, to keep it well under the waiver. [video=youtube;lV5o9YWWrHo]https://www.youtube.com/watch?v=lV5o9YWWrHo[/video]
Ok cool! How many newton seconds was the motor? What Mach number did it reach to? I am trying to get a baseline in reference to my design and using the CTI O3400.
So what do you guys suggest is the best fin material for high speed min diameter flights? I know G10 is easily obtainable but there are others i am sure.
Fin flutter is likely going to be your enemy at the speeds you are going. High root length to span fins
I don't see a lot of commets, so I'll give my two cents.
I think you want the fin can to be as stiff as possible, and not have some degree of flexibilty, so I don't see any benefit in using fiberglass for the tip-to-tip over CF, except for cost. I'd use the CF.
Also, if you are trying to limit your altitude to stay under a waiver, by using 3 relatively large fins, you could accomplish the same goal (more drag) by using four smaller fins. Four fins with shorter span are more likely to hold together, for a flight going mach 3.
The reason why I am doing it this is I am using my best judgment. I have been talking to am guy here on the forum and he also is a vendor in our hobby. After talking with him this is what he suggested. He has flown min diameter past Mach 4 with successful results. I just wanted to do 3 layers of 5.7oz 2x2 twill on my bird, but he recomemded doing it this way. He said doing 2 layers of CF on each side of fin before attaching fin to airframe. Then he said once fins are on do 3 layers of T2T using 4 oz S-Glass. Also, when attaching the fins to the airframe using Kevlar bulp with high temp epoxy. So I am just taking his suggestions. Right or Wrong IDK I am just trying to take a fresh aproach using all the knowledge from people in our hobby. His fin suggestion was using nomex honey comb with g10 then carbon, but since I already had the G10 fins he suggested I do what I did in the previous post.
What's the point of painting a rocket designed for M3/4? It will just burn off leaving a mess.
What's the point of painting a rocket designed for M3/4? It will just burn off leaving a mess.
The post cure should not damage the rocket unless you go over the glass transition of the epoxy. Majority of which are 180+, but a post cure below that should hold.