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BP Rocket

Blaf

By Blaf
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Blaf Newbie

Blaf

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Happy New Year guys!

I'll write a thorough report on That Night soon...meanwhile, you can see what remains after firing one of those small plastic rockets topped with salute. Stick and body are separated but not from heat genearted by burning, I forced them apart just to see how the glue holds. It held OK but I used too much force...

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Best wishes from Blaf

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Blaf Newbie

Blaf

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The latest report:

The Big Day came....but I have to disappoint you guys. The truth is, I'm the most disappointed one here. But that's life. We all learn from our own errors....or so. I must say I had high expectations regarding the Big One but it all turned out to be opposite. At about 23,00 hours I took my Pyro Bag (yes, I've got one for the purpose), 10 pcs of small rockets with salutes (you've seen them already), spare fuses, lighter, some BP in a small container just in case, some isolating tape, an umbrella (it was raining slightly...), the Big One and finally my humble self. An commercial firework display was planned at midnight and I wanted to fire all of my stuff before it starts. Walking downtown was very nice and I thought I could do it more often instead of using a car all the time. It would be much healthier. And so, I thought about launch site...hmmmm, somewhere between my block and city center there's a wide empty space with playgrounds and a big concrete building almost abandoned. Perfect place for something that you're not sure of working at all. Everyone has already gone downtown and I saw almost no people on the streets. But boy, city blocks were rumbling with constant thundering and flashes. Sporadically, here and there, rockets would leave their tails accross night sky followed by various effects. Nice scenery for things yet to come. I picked place in shade, a flat piece of ground with fence all around, away from curious eyes of bypassers. There, I mounted my launching device, a piece of aluminium tube of 12mm diameter with sharp pick at lower end, sticked almost vertically just slightly slanted to south. Here I had a dilemma – what to fire first, those small ones or the Big One. After a short consideration, I decided to set the Big One first. Someone said it resembled a German hand-grenade...it's true. And so, everything was done by the book, much longer fuse was used as to leave more time to retreat. I lit the fuse, ran some 10 meters away and turned to the scene just on time to see it exploding right at the site! It went one meter up and exploded blowing stars vertically. The BANG was very loud but of rather low frequency. I had no time to take cover at all...as a matter of fact I didn't have to as all stars burned in their apogee. What a shame, what a waste of good stars and wooden stick, a nice strong tube, my work...everything. The thing is – I don't know what went wrong! Maybe, just maybe, I left the nozzle too small...5mm...it maybe should have been at least 6-7 for this tube diameter. In despair, I wanted to collect my equipment and turn back home...but my curious mind prevailed again and I stayed. Hidden from public, discredited and sad...I stayed for some time sorting impressions. What a hell, it's once in a year event and I should fire everything I have. Having said that, small rockets were taken out and one by one launched without a single problem. All of them went up over 50m in height and ended with a loud bang! Huh, 5 minutes of glory that I waited for finally came. After the last one went off, I took my gear and slowly walked downtown, thinking about my future moves and at the end attended a nice commercial display in the city port. But frankly, there was much more fireworks of all kinds thrown by citizens that night...it's something you could compare with Beiruth some 20 years ago. That's it guys...wish I could give you a nice, immaculate report but Mrs. Faith (or my negligence) spoiled the fun. Hope you all forgive me one day...or even sooner.

Blaf (the surviving one...)

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Exhile Newbie

Exhile

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Alltough I wasn't able to see my own devices I have the films of them.

First off all the starmines, since I had a flu which lasted for a week and a half I was able of making 3 of the little babys, two out of three were magnificent while the last one gave some sort of strange fountain.

Next were the rockets, one with a core not completely through the sas and all the rest little ones with a core which runs through the sas completely.
Now the problem with the complete core is the timing and delay, due to the fuse who reaches the end in seconds, my stars went of at about 15 meters while the rocket was going for its highest point, next there were about two rockets with a 2.5" shell and blue stars, those things were crazy.

A nice break with canister shells and a beautiful flower of blue, unfortunatly I wasn't able of making shells so I'll do that asap to have the satisfaction of it.

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Blaf Newbie

Blaf

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Hi Exhile!

Glad to hear from you again. Sadly, you couldn't be at the site because of flu...it must have been owesome to stay at home and watch your devices going off on video. Better luck next time!
As for core, one of the problems that caused my rocket to explode could be the core lenght and its dia. Let me see...nozzle dia=5mm, grain dia=20mm, grain lenght=80mm, core dia=3mm (yes, I drilled it after ramming), core lenght=30mm. It's not too much but it just might have caused pressure build-up. Next time I'll make one of the same proportions but with a larger nozzle and see what happens. The truth is - I never tested a rocket engine of this size before. But hay, how much testing took NASA to perfect their rockets!?! See?

Blaf

p.s. I just wonder what happened to other guys...

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Alexio Newbie

Alexio

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For such a big rocket I'd rather use candy instead of BP. I think it makes the risk of a CATO much smaller.

But anyway, sometimes the unpredictability of fireworks is what makes them fun to make, to a certain extent of course (with all safety rules regarded).

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Blaf Newbie

Blaf

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Alexio, your words brought a bit of relief...unpredictability is what makes this so thrilling. Anyhow, I feel little incomplete because of the last CATO and therefore I made an exact copy of it (without payload, of course) but with a shorter grain and larger dia nozzle...we'll see what happens this time.

Blaf

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Ananas Newbie

Ananas

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C'mon guys!

Anyone else has anything to confes? No? So, in other words it implies that I'm the only one making mistakes here...

Blaf

p.s. Thanks Duvel for support.


I started a small bushfire once with a Sodium chlorate/sugar rocket. I hadn't stabilized it enough, but that was a long time ago and I've learned a lot since then.

For the rest, I'm starting with some exams next thursday so I don't have much time for pyrotechnics. I will however, try to finish my metalgrinder.
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Oscar Newbie

Oscar

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Why have you so badly hurt seflconfidence. Next time beter. People learn from their own mistakes. At least I do. Look very good what went wrong. Than you now what to do next time. It is just like you fall en get up again.

Not everything works fine with me, if something went wrong or it gave a loud bang instead of smoke. I would check out wat has failed. So I wont do that again or I do it different way.

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  • 4 weeks later...
Blaf Newbie

Blaf

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I know you all wait to hear if MarkII with reduced charge ever flew... Sorry, I didn't make that second attempt yet. The rocket still proudly stands on one of my shelves begging to get some action. No rocket will ever dictate my life. I'll pick the best time and place but not yet...

Blaf

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  • 3 weeks later...
Blaf Newbie

Blaf

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And here is the latest launch report:

You've all been waiting to hear another disastrous report, haven't you? Not this time. As I mentioned in my last post on this matter, the MarkII version of the same engine diameter was filled with BP at only half of its capacity. Additionally, nozzle hole was widened to 6mm dia. Remeber, the first one that gone BANG was 5mm only. Note this – grain wasn't drilled this time, just plainly rammed grain. A tiny stick of 60cm in lenght was fastened to the engine body and long piece of my domestic brewed fuse sticked through nozzle kissing the grain. No payload, no complications...I just wanted to see if this variation works at all. It was windy day, cloudy a bit and it just happened that I gave hand to my friend replacing his old boat-engine. We have done it in a snap and then I unfolded my poorly looking device to celebrate successfully done job. We couldn't find any fitting tube or at least bottle on his boat...frankly, we didn't look to hard. There were practically no people there as my friends boat floats at far corner of marina – a perfect spot to test fire it. And so, the stabilizer stick was put between two massive rocks, skewed a bit to seaside, the fuse lit and we retreated some 10 meters. Low pitched whooosh! was heard and it all rushed up at moderate speed...moderate in comparison to smaller BP rockets I made for New Year. This device burned rather long time (2-3 seconds) and reached at least 60 meters in height, thrusting modrately through entire flight. Ballistics wasn't perfect and it was spinning a bit all the way up and ended in the sea some 50 meters from us. So, it flew finally but I doubt it could take any payload up. Thrust should have been much stronger...therefore shallow grain hole should be made next time. How about this, ha?

Blaf

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  • 2 weeks later...
Blaf Newbie

Blaf

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I made so called MkIII. This one has grain 75mm in lenght, shallow core of 15mm in depth (4mm diameter) and 5,5mm nozzle hole. Remeber, the last one had 6mm hole and hadn't got sufficient thrust to carry any payload. This time I made a cardboard shell little larger than motor dia, glued on top with two dozens of Gold & Silver Rain stars mixed with granulated BP. Now, I'm looking for a suitable stabilizer stick as it requres at least 70cm of it... and a nice occasion to launch it, heh.
Image follows soon...

Blaf

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Blaf Newbie

Blaf

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I know, my sticks were purchased in garden shop as well but I could find 45cm lenght only....maybe I should ask for longer ones next time, heh?
Exhile, could you drop by KNO3+Sugar+Sulphur propellant topic and check the last Nitroglycerine question about it? Thanks!

Blaf

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