high performers lpr

[saunassa]

from my fleet of rockets the Comanche-3 gets the vote for altitude.

painted it red so it would show up better against the sky. ripped off the pad and zoom.

Hey, it was the first launch and if i was to lose it i wanted to see it really go.

Check it out.

D12-0, C6-0, C6-7

 

[GL-P]

I love the Commanche. Just a pain to find!!!

 

[r1dermon]

try a commanche with an F21 booster stage, and 2 D21 uppers....you want altitude? PEACE. lol. i bet it'd break a mile...it'd be like a 30 dollar flight though..

 

[bachsta]

a flight that costs more than the rocket is a bit ridiculous i think

 

[r1dermon]

hey man, not if it goes a mile high!!

 

[bachsta]

i dont know. id rather get a better rocket if im gonna spend that much on a flight

 

[solrules]

Originally posted by r1dermon
try a commanche with an F21 booster stage, and 2 D21 uppers....you want altitude? PEACE. lol. i bet it'd break a mile...it'd be like a 30 dollar flight though..

except for the fact that you can't CHAD stage composite motors.

 

[bachsta]

lol

 

[TheRadiator]

Let's not forget that were doing LPR. I live in a land where black powder still rules the day! But if Estes would just make that E9-0!

 

[r1dermon]

sol...who says? you stuff some rifle grade BP down the core and then stuff some tissue paper between that and the ejection charge on the composite. surely that'll work.

 

[Stymye]

most composites that size light from the top of the grain not the nozzle.

I'm really interested in hearing your experience with it.

 

[r1dermon]

yes, that is correct. however, they light from the top and burn through the bottom. so if you were to stuff the core with slow burning BP(which is still relatively fast burning) and then connect that to the ejection charge via some tissue paper or something flamable...im sure it could be done...

 

[solrules]

Originally posted by r1dermon
sol...who says? you stuff some rifle grade BP down the core and then stuff some tissue paper between that and the ejection charge on the composite. surely that'll work.

Says the composite rocket gods

Composite motors are core burners. This means that propellent, even at the forward end, is burning at the same time the aft propellant is, too. This means you cannot simply stick a fuse at the end of the delay and think it will light. You would have to find the burn rate of the delay charge, under the pressure designed for the motor (delays burn at different rates under different pressures!), calculate the amount of delay you would have to drill out to make the delay burn through right at motor burnout. Then you have the problem of lighting the next motor! You would have to use a shielded (because you don't light composite at the aft nozzle end.....only part of the motor would light!), fast burning fuse that comes out of the perfect hole you drilled for the first stage motor, and feed it to the forward end of the second motor. Then you have to do the same procedure all over again for the third stage motor. Pretty absurd if you ask me.

Along with invalidating your Aerotech warranty by drilling the delay, it would probably not be allwed at commercial launches. You would be much better off buying a good accelerometer....

Do not CHAD stage composites! Use the safer method: electronics!

 

[edwardw]

Originally posted by r1dermon
so if you were to stuff the core with slow burning BP(which is still relatively fast burning) and then connect that to the ejection charge via some tissue paper or something flamable...im sure it could be done...

I'm pretty sure stuffing the core with BP is a great way to dissasemble your case into lots of pieces that won't fit back together.

Electronics and an igniter (e-match with pyrogen or something similar) is the best way to insure ignition. On our Delta II project we have to airstart 3 outboard motors on the rocket. We are using a PET Timer from Missileworks and an e-match for each motor. They are Cesaroni motors which like to light up very fast and reliably.

Edward

 

[saunassa]

if i want altitude i will launch the minimum dia rocket i am working on now. rocksim at 3700+ at calculated 680mph all with a f21.

now that is if it stays together and it is built correctly. gonna use the minimum streamer so that i have a chance (ya right) of recovering it. figure watching it go out of sight will be my reward.

 

[r1dermon]

if you stuff the core loosely with BP it wont blow apart. especially BP. using perchlorates and aluminum powder is what will do that. BP will make a pop and accelerate the burn rate over the entire core. i do it with my sugar rockets all the time. even 2 ounces of pure BP wont blow a pressure rated PVC pipe. unless its closed off....whatever though, at the cost of composite motors...i probably wouldnt try it anyway. its just a cool thought for the experimental field. quickmatch would probably work much more like an igniter, because it burns up to 500fps and you can leave JUST the end exposed, to light the top of the motor.

 

[edwardw]

Originally posted by r1dermon
even 2 ounces of pure BP wont blow a pressure rated PVC pipe. unless its closed off....whatever though

A rocket motor is a partiall closed off pipe. You have a forward closure sealing one end and then a nozzle restricting the other end. I think that stuffing the core with BP (and stuffing to me implies your getting all you can in there) is asking for a CATO upon ignition. BP burns fast anyway, and when it's confined it burns even faster.

At the cost of an e-match ($1.50) and a timer ($30ish) you can reliably light second stages w/o worries and methods that involve lots of BP.


Edward

 

[r1dermon]

ok, i was going to say something, but this is straying way off topic. i'll just leave it at that.