BP pyrotechnic rocket altitude

[Eric70]

I make BP coreburner rockets for pyrotechnic purposes and I realize there are variables involved such as fuel formulation, header weight and weather conditions, but is there a standard expectation or general rule to how high a BP coreburner rocket should fly? If there are any responses to this post, perhaps we should discuss "should fly" and "can fly."

 

This is guessing but it is pretty close - my 1lb coreburners with a light header are consistently hitting around 600 feet. The 8 oz ones appear to be hitting close to 400 feet provided they have a light header. The 3lb ones are somewhere between 650 and 800 feet, I am still dialing in the fuel and they have no headers. Are these heights normal and considered what one should expect?

 

Long ago I used to be into model rockets (Estes). The Mean Machine would hit 800 feet, another model rocket would hit 1500 feet, and so on. With those memories my eyes have a ballpark idea of how high my pyrotechnic rockets are going.

 

Sure, I have seen people post in other sites that their BP rockets are hitting 2,000 feet, blah blah blah, that is hard to believe but who am I to say!

 

In other words, in the different tutorials on making BP rockets that I have read, I don't think I have ever seen a statement that says "this size rocket should be able to hit XXX height." I do realize one does not want to send a rocket sky-high because it will diminish the header effects. On the other hand, what if you just want to shoot a rocket way up there without a header for the tail effects?

 

Eric

[fredjr]

Salute headers make it easier to judge distance. When you see the flash count until you hear the bang and do the math based on speed of sound in air - 1,125 ft/s. Video makes it easier to get real time as most people count too fast and say their rockets are higher than reality. But you would be amazed what some rockets will do. This is NOT BP but http://pyrobin.com/files/mang%20core%20-%20whistle%20end.wmv Edited October 25, 2009 by fredjr

[Swede]

Eric, I think the number of variables makes it almost impossible to say "This should reach 600 feet with a 10 gram payload" etc. Two guys with identical fuels, tubes, and sticks, pressing or ramming, will probably have differing altitudes, just due to different techniques. I personally think a rocket looks more dramatic, and provides a better show, when it chugs or labors to a safe altitude, preferably with a nice tail, before the header bursts, rather than "Zwoop" it's gone - then burst. Heck I am happy if everything functions properly and the altitude is a safe one.

 

Aerodynamically, a true model rocket just kicks a pyrotechnic motor on a stick all over the place. I don't know the numbers, but I would guess the same engine, with stick vs. rocket body, would see 25% to 50% less altitude.

[new2pyro]

hey eric check out my 1lb core burner vids i posted. the first had a 2 1/2" plastic heading, the second which went higher, but hit the ground, had a 2" rolled heading i am happy with the height of both. the visuals are right at this altitude. i'm sure end burners would go higher than cores as the burn time is longer. i use 6/3/1 mix with willow charcoal.

[new2pyro]

i sent a 3lb sugar rocket out of sight but like i said it had a 5 inch core in a 10 inch tube which is short compared to bp coring. the mix was hot 2/1

[Eric70]

Thanks for the information, guys. I will have to try to capture some of my rockets on video someday.

[TYRONEEZEKIEL]

Swede, you are exactly right on the model rocket bit. An estes model rocket will see extremely higher performance over pyro rockets. Aerodynamics are exponentially better in model rockets. A nosecone will add so much altitude, its astonishing.

[scarbelly]

That's interesting... I one time taped an estes rocket engine to a stick (probably like 2 - 2.5 feet long) and it completely outperformed the rockets with bodies made for the purpose... It accelerated to speed much more rapidly. I'd guess it went at least 50 feet higher. It wasn't quite as straight of a flight however (it corkscrewed a bit towards the end up the flight) I thought it had to do with the weight difference.

[Eric70]

I would assume that the estes rocket engines contain a hotter fuel for performance purposes. Those engines as far as I know are endburners.

 

As for Class C pyrotechnic rockets, I have dissected some of the spent ones and it is funny how small the motors are on them. Low cost manufacturing. I think most of them are endburners with hot fuel that gets them up to around 250 feet.

 

23 years ago a fireworks outfit from Deerfield, Ohio had an ad in a magazine for some fireworks missiles. Stuff like that you could not buy in Minnesota, I was 15 or 16 with a checking account already and I sent away for it. They were called "Flight of the Phoenix." I recovered a spent one and still have it. They were a missile with the plastic one-piece fins and plastic nose cone. Basically had an 8 oz motor in them (1/2") and went up 300-400 feet ending with a few stars. I am humoring the idea of flying the recovered one again with one of my 8 oz coreburners. You can still buy similar rockets like these, it was just funny how a high school kid in Minnesota could get such back in the day.

 

That's interesting... I one time taped an estes rocket engine to a stick (probably like 2 - 2.5 feet long) and it completely outperformed the rockets with bodies made for the purpose... It accelerated to speed much more rapidly. I'd guess it went at least 50 feet higher. It wasn't quite as straight of a flight however (it corkscrewed a bit towards the end up the flight) I thought it had to do with the weight difference.