15 replies to this topic

[cplmac]

I've been working my way to lifting a 12" shell for about a year now, and tonight I finally got it done. The rocket stands about 9' tall, weighs in at 36 pounds and pretty much kicked off the next goal. The motor is a 3" ID whistle rocket with a 6" long by 1.5" diameter core and 3" of delay topped off with a wood plug to keep the fuel in the motor. The shell itself weighed about 26 pounds and was my first go at a 12", not the best looking 12 but it will do for this rocket. Thought I would share the vid with fellow pyros across the pond, haven't been on here in a while. Enjoy!


I'm 5'10"


3" whistle rocket with 12" header

Edited by cplmac, 22 October 2008 - 04:54 AM.

[spanner]

I hope it's just my connection or something, but the video leaves much to the imagination.

But congrats on getting that beast up in any event!

[pjalchemist]

The video was a bit of a let down, sound was too low on the recording. Anyway wow, the shell was massive, nice big thunder bang. Not so sure about whistle though, maybe the core could be smaller? Almost looked like it was still under thrust when the shell went off!

[dr thrust]

the video worked perfect for me?, downloaded though "bit comet" and the mpcstar video player "add on" will play just about anything. great rocket well done what was the total weight did you measure? ho whats next a "maned flight"

[bigtonyicu]

The video was a bit of a let down, sound was too low on the recording. Anyway wow, the shell was massive, nice big thunder bang. Not so sure about whistle though, maybe the core could be smaller? Almost looked like it was still under thrust when the shell went off!

He really can't make the core much smaller or else he won't have enough thrust on take off to accelerate the shell on a steady straight trajectory.

Really nice motor; any clue to the thrust and what kind of pressure did you use to press the fuel in?

Keep up to good work!

[cplmac]

On the video problem, you might need an HD codec for wmp, the video is 1440x1080 after being renderred from a Sony FX-1. It would be 1920 but Sony uses rectangular pixel sensors in that camera so it comes to 1440. Like Tony said, I'm not makinig the core any shorter because that rocket is heavy. I have no idea what the thrust is on that motor but it pushed a 36 pound rocket pretty easily, if I had to guess I'd say the thrust was at least 100 pounds. Loading pressure on the fuel was about 3500 psi.

Edited by cplmac, 22 October 2008 - 03:36 PM.

[crystal palace fireworks]

Any chance of uploading it on Youtube?

[wjames]

give it 15 mins and it'll be availible here

http://www.youtube.com/v/aJSvGQHtP7s

Edited by wjames, 22 October 2008 - 04:16 PM.

[Creepin_pyro]

Very nice indeed. Looking forward to seeing a volley go up with some slightly better headers on them : P

I think you can safely bulkhead-fuse the next one then, that thing was still going strong when the shell burst.

Sound was absolutely fine for me - I take it you ended up using an external mic? Certainly makes for some tasty deep bass tones : )

Would've loved to see a close-prox launch angle, but I certainly wouldn't be volunteering for the job! I can imagine the howl from the motor hurting a bit at close range...

[cplmac]

Are people still having trouble downloading it or just playing it? It's up on my youtube channel but like all things youtube the resolution is garbage and you can't really make out the TT comets. I short fused this in case there was an errant trajectory, I won't be bulkhead fusing because I use a wood plug at the top for a bulkhead, it's the only way to keep the fuel from blowing through the top of the motor. I can dial in the timing better now that I know the motor can push it properly.

[cooperman435]

pjalchemist did u mean to make the core narrower Ie the nozzle too to increase thrust?

[cplmac]

There is no nozzle on this rocket, it's a whistle rocket.

[spanner]

I can dial in the timing better now that I know the motor can push it properly.

At first I was surprised that you hadn't tested the motor first to be sure. But I suppose at that size, there's cost and time/labor to be considered.

[cplmac]

At first I was surprised that you hadn't tested the motor first to be sure. But I suppose at that size, there's cost and time/labor to be considered.

I did test it first with a 21 pound dummy header back in February.

Test rocket with dummy header

[Night Owl]

I did test it first with a 21 pound dummy header back in February.

Test rocket with dummy header

What a rocket!!! nice work cplmac:)