how much BP kills the whistle of whistle?

[californiapyro]

I recently acquired a 2 oz rocket tooling set, and am working on lifting 2 inch shells. I have gotten good height out of them with nozzleless BP, but need more thrust. Is it possible to do a pusher core type whistle with a whistle/bp hybrid mix, and if so how much BP is needed to silence the whistle (i'm trying to be quiet, the neighbors don't like noise) your help is appreciated!

thanks,

-Cali

 

 

[Potassiumchlorate]

I'm not very experienced with rockets, but I got very powerful ones by using a 3/4" stinger spindle and ordinary BP 75:15:10. The core was bigger than by an endburner but smaller than by a coreburner. The tube was the same length as a coreburner, i.e. 3/4"x10. A stinger uses ordinary BP but also has a side nozzle to make it rotate and to release some gas pressure.

[Mumbles]

Most "standard" core burners are going to be 7.5" long, not 10". There are a few that deviate from the 10x ID rule of thumb.

 

It doesn't take a lot to kill the whistle sound. I take it you've heard of Steve LaDuke's hybrid rockets? It's a hot whistle fuel with 10% airfloat charcoal. No sound. Dan Thames heavy lifting fuel is whistle with 5% coarse charcoal, again relatively quiet. These both have specialized spindes and instructions to make them, but if you start with 10% BP you should probably be good as far as sound goes. You can also possibly spice up your BP by adding some percentage of whistle mix if you're going to stick with a nozzless design.

[dagabu]

I don't get more then a "chirp" from whistle with any charcoal or BP added.

 

-dag

[drthrust]

strangely enough ,in the hunt for nozzle-less propellants ive had a 70 perc, 40 willow motor "whistle" of sorts http://www.youtube.com/watch?v=s9SeyIDmXtA

[Mumbles]

I don't get more then a "chirp" from whistle with any charcoal or BP added.

 

-dag

 

That's good to know. I know Steve's fuel doesn't sound much different than a powerful BP rocket. I was unsure if Dan Thames' was because of the fuel or the spindle geometry.

[nater]

Ned Gorski launched some rockets made with Dan Thames fuel at Tri State, and they had a noticeable howl. It wasn't a loud whistle for a 6lb motor, but was much more than the BP woosh. i havent tried or seen anyone use that fuel on a 1lb motor, but i dont think it would be appropriate with picky neighbors.

[mabuse00]

Just curious:

In my experience Perchlorate mixtures become very much more sensitive if suphur is involved.

How does that apply to those hybrid fuels?

[dagabu]

Ned Gorski launched some rockets made with Dan Thames fuel at Tri State, and they had a noticeable howl. It wasn't a loud whistle for a 6lb motor, but was much more than the BP woosh. i havent tried or seen anyone use that fuel on a 1lb motor, but i dont think it would be appropriate with picky neighbors.

 

I would pick Dan and Ned's brain about what the delay was, the fuel along the spindle will chirp with high charcoal content but the delay is often whistle with Ti or other metals.

 

-dag

[nater]

i will ask them. Ned's rockets had a nice raspy tone in the delay, but wasnt like a typical whistle. he mentioned what he used while we were all building, but i cant remember what he said other than a pinch of ti in the mix just above the spindle. i am also not sure how that fuel will work on the u/h tooling, the diminsions they use are different yet, but i am wondering if that nabenz fuel with the charcoal will work as the only fuel on the u/h design. thats on my list of things to try next summer or at pgi.

[anapogeetoofar]

Doesn't cplmac make some kind of "whisper" rocket? I think its nitrate based though, not sure if that's what ye be after.

I could have sworn I saw a whole presentation about whistle and how additives affect it. Not the one on Dan's site, It was something like: "oscillating combustion propellants" Or something like that. In any case, there were decibel readings for the various additives, might be of some help.

[californiapyro]

thank you all for your responses on this topic ive been doing some tests, and on pusher tooling whistle:bp 50:50 is no noise but not a lot of thrust, and 80:20 whistle:bp makes an ear-splitting racket with decent thrust. I wonder why theres so much noise... anyone? Edited November 21, 2011 by californiapyro

[Col]

If you`re using red iron oxide for the catalyst, i`d give copper oxychloride a go with the 50/50 (by volume) bp/whistle mix.

[Mumbles]

Is it still whistling with 20% BP in there, or just making an overly loud thrust?

[dagabu]

Crazy!!!

 

I add 5% charcoal to my red iron whistle and I get a loud flatulence sound but NO whistle at all. I also hear at least a dozen "Super Whistle Fueled" rockets by both Dan and Ned at PGI and except for a "chirp" at the start, there was only a loud WOOSH od a sound for them.

 

I will dig up some video of what i am talking about when I get home...

 

-dag

 

 

[nater]

Here is a couple of Ned's large rockets that he launched at Tri-State. Especially on the first one, I can hear a little whistle when it immediately lifts off, maybe that is what Dagabu is referring to as a chirp. It is nowhere near as loud as a 6lb benzoate whistle rocket, but it isn't discreet either. I think hot BP fuel and anything with whistle in it will not be all that quiet.

 

 

http://youtu.be/dwoq3v71L8g

 

[californiapyro]

nah it's a definite whistle, it's the darndest thing! wish I had a vid or at least an audio so you could hear it, I thought for sure it would be quiet. now, my mix is overcatalyzed by accident (3% fe2o3) would that have to do with it?