Epic failure but so awseome

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MadDoza

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Decided to push the envelope, launched an H90 in my dual deploy star orbiter, watched it rip apart in the sky. Once I found the ebay the strattologger beeped out 1904 feet with a top speed of 1064mph it was pretty insane. This was all that was left. Totally worth it.

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Rocket porn.. LOVE IT !!!

To say I have a pile similar, due to vey close circumstances.. would be correct..

Push that envelop !!!
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I'm launching my 2.6" fg screech on a L935 to mach 2.9 And hopefully around 19,000 feet. I want to do a MD 3" rocket on an M2245 to really push the envelope and try to get to 50,000 feet.

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I have the Mini screech, Hopefully I can break Mach 1 with it next go around. I wonder if I would've used plywood fins instead of papered balsa if it would've held up. Honestly I'm surprised they held up to break 1000 mph.
 
i LOVE IT

We are planning an 'event' at one of our launches.... highest and fastest on 'stock' PSII, I am calling it "ShredStes"
 
I think your sim is a bit optimistic on the mach 2.9...probably closer to 2.1 if your .0625" thick fins don't fail.

That sounds more likely. I’d imagine those fins will need some help.

the sim for my screech says M 1.8 and 18K. Maybe a mistype?
 
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That sounds more likely. I’d imagine those fins will need some help.

the sim for my screech says M 1.8 and 18K. Maybe a mistype?
My bad, I checked the sim again and it says mach 2.38. I built my screech really light, but I have 1" diameter fillets on it. You really think I need to reinforce the fins a bit? Even with those beefy as hell fillets? If so I could do t2t layup on them. I thought the through the wall mounting and internal fillets with rocketpoxy would be strong enough to hold onto the fins.
 
My bad, I checked the sim again and it says mach 2.38. I built my screech really light, but I have 1" diameter fillets on it. You really think I need to reinforce the fins a bit? Even with those beefy as hell fillets? If so I could do t2t layup on them. I thought the through the wall mounting and internal fillets with rocketpoxy would be strong enough to hold onto the fins.

i don’t think the fillets will fail. I would take a close look at finsim and evaluate if the fins themselves will flutter and basically explode.
 
My bad, I checked the sim again and it says mach 2.38. I built my screech really light, but I have 1" diameter fillets on it. You really think I need to reinforce the fins a bit? Even with those beefy as hell fillets? If so I could do t2t layup on them. I thought the through the wall mounting and internal fillets with rocketpoxy would be strong enough to hold onto the fins.

Fillets are definitely going to help. Don't get me wrong I am not saying with any confidence that I feel that your fins would fail, but of all the components in the design 1/16th G10 fins for Mach 2 flight may be your weak link.

I agree with Dave's recommendation. Check the numbers to gain a bit more confidence on your flight profile and run the fins through FinSim. If the numbers provide a good margin then I would say go with the numbers that is if you're confident you did the analysis correctly. If the numbers are marginal then I would go on the conservative side and do some reinforcing such as a single layer T2T, or whatever you feel is warranted.

Having said that, safety factor aside, what you do should be dependent on your goals. If you just want to push it for a personal best or record attempt then that is when pushing the limits is justified, without being reckless. But if you want to confidently enjoy many flights with some abuse on the rocket then that is when some over-building is well justified. The controversial and subjective thing is what constitutes over-building.

There is another reason to "over-build" and that is something that I practice. I like to use new building techniques in order to gain some hands on experience on designs that don't require it, this way I am better experienced for builds that do require it.
 
Fillets are definitely going to help. Don't get me wrong I am not saying with any confidence that I feel that your fins would fail, but of all the components in the design 1/16th G10 fins for Mach 2 flight may be your weak link.

I agree with Dave's recommendation. Check the numbers to gain a bit more confidence on your flight profile and run the fins through FinSim. If the numbers provide a good margin then I would say go with the numbers that is if you're confident you did the analysis correctly. If the numbers are marginal then I would go on the conservative side and do some reinforcing such as a single layer T2T, or whatever you feel is warranted.

Having said that, safety factor aside, what you do should be dependent on your goals. If you just want to push it for a personal best or record attempt then that is when pushing the limits is justified, without being reckless. But if you want to confidently enjoy many flights with some abuse on the rocket then that is when some over-building is well justified. The controversial and subjective thing is what constitutes over-building.

There is another reason to "over-build" and that is something that I practice. I like to use new building techniques in order to gain some hands on experience on designs that don't require it, this way I am better experienced for builds that do require it.

That make a lot of sense. I just emailed to get a copy of finsim with my school email, so hopefully that's enough proof to get it. I couldn't find a way to pay for it, which I wouldn't mind paying something for it, but all well. I'll just wait for the response. I like to overbuild my rockets too, but I really want to push the envelope with this rocket. I'm trying for 20,000 feet, and my sim is putting it 500 feet short of what I'm going for, but I also don't want to loose my investment in this rocket, as I really do like it.

Thanks,
Matthew
 
That must have been impressive to watch. I'm working on the same idea now, a cardboard Tomach that I'm hoping to fly with an I-205. Hopefully it won't meet the same fate.
 
That would be a good opportunity to get stupid crazy with it. Be a lot of MIA's.
 
You would've loved my first ever SEDS launch. Mach 1.5 then interstage imploded CF airframe and shredded tubes. We were trying for 22k ft on L-1 motors. The L-3 dudes were like horsesh*tting reasons at many launch sites to keep us from launching there via email. One said we needed and L-2 then redacted that saying we had to be the FIRST or last launch to minimize risks. Then UROC let us launch. No questions. And that RSO showed us a shredded L-3 with some chuckles. Apparently a AT i1299N is too much thrust for sanded CF. It was only M1.5 in 0.3s. We told competitors don't use that motor. It was a K class thrust curve and we had no experience. We showed broken rocket pieces. They laughed. We couldn't tilt head fast enough and a tracker couldn't track it. Implodes an interstage.

We had to launch another more sane rocket to pass a design class last fall and get an award. You'll learn a lot by breaking something.
 
That make a lot of sense. I just emailed to get a copy of finsim with my school email, so hopefully that's enough proof to get it. I couldn't find a way to pay for it, which I wouldn't mind paying something for it, but all well. I'll just wait for the response. I like to overbuild my rockets too, but I really want to push the envelope with this rocket. I'm trying for 20,000 feet, and my sim is putting it 500 feet short of what I'm going for, but I also don't want to loose my investment in this rocket, as I really do like it.

Thanks,
Matthew
All the university attempts at 20,000 ft multistages died horridly last year in L-1 motors. Stick to 19.5 k ft and don't over stress the airframe or electronics. If you want to be optimistic try to beat the current TRA record. Honestly that's hard enough and still realistic.
 
Honestly I'm surprised they held up to break 1000 mph.

Even a stock Star Orbiter at a mere 6oz cannot achieve 1000 mph on an H90. Baro altimeters like Stratto are not very good at velocity, especially after a shred event. Check your simulation for a better estimate of top speed.
 
One thing to remember is that improving the surface finish on a 19kft flight even a little bit could easily get it over 20k. And increase the speed...and the probability of a shred :tongue:
 
Decided to push the envelope, launched an H90 in my dual deploy star orbiter, watched it rip apart in the sky. Once I found the ebay the strattologger beeped out 1904 feet with a top speed of 1064mph it was pretty insane. This was all that was left. Totally worth it.

I think it is called "Destructive Testing"
 
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