whistleing rocket

I believe he is referring to something similar to the whistles attached to some fountains/rockets but are fused and function separately from the primary device. However. Galic Acid/Potassium Chlorate whistle mix gives good thrust and can be pressed into an unchoked case and whistle while it "rocks". I haven't tried the Perchlorate/Benzoate formulae in rockets though so they may work also.

I'm not sure exactly what the original author of the post had in mind. I personally have never used chlorate / gallic acid, although I've seen it demonstrated. The perc / benzoate mixtures give good sound output compared with the perc / salicylate mixtures at the expense of thrust. Ms. Partin describes analysis of sound output from perc-based variations of these mixtures in PT XVI (1995). Öztap describes the use of chlorate / salicylate-based whistle mixes in his articles in Pyrotechnica. XI (1987) and PT XIII (1990). These compositions are said to provide thrust superior to that of the perc-based mixtures commonly used by persons making rocket motors experimentally in the US and elsewhere.

Of course, this should not be taken to mean that I recommend such mixtures. It is not coincidental that I never tried them out back when I was actively experimenting. I suspect other rocket makers in the US have tried them out. However, the performance of a well-tuned perc-salicylate mixture pressed with a well-designed set of tooling is good enough that for most there is little need to make the jump to chlorate for increased thrust at the expense of the likelihood of a CATO or of an explosion during the actual pressing of the motor or mixing of the composition.

For those unfamiliar with the performance of these (perc-based) propellants, I would say that they are more potent than the BP type propellant commonly encountered in Estes type rockets but less potent than the AP-based composites encountered typically in HP rocketry. They are more subject to CATO than either especially if inexpertly made or carelessly handled. OTOH, they don't require to be mixed under a vacuum, nor to be prepared from commercial BP. They are IMO more visually and audibly impressive than ordinary rocket motors as well. Some variants on the compositions fairly scream upon launch -- the term "whistle" in these cases is something of an understatement.

Just for good measure, I should also mention the classic article on the whistling phenomenon itself, W. R. Maxwell. "Pyrotechnic Whistles." Fourth Symposium on Combustion, paper no, 111. (Baltimore: Williams & Wilkins,

In any case, the references I've given should provide more than an adequate beginning for the investigation of whistling rockets for the serious amateur builder.

The 1.4g item "Killer Bee's" is an example of what I believe he was asking, a fountain instead of a rocket though, with 3? or 4? whistles attached to the fountain case and fused through the side of the casing so as to separate the whistles in timing.

The experimenter should pay careful heed to the literature describing fusing of whistles. It seems that even the slightest hint of constriction at startup, including glued in place fuses and excessive flammable wadding to hold the fuse in place, will cause CATO in 99 + % of tries. It is for the above reason that I haven't given formulae. In my opinion if a person has sufficient interest in making a whistling rocket that he will procure the -somewhat- exotic chemicals he will also have sufficient interest in his own safety to pursue as much literature as he can be led to on the construction. Hardt, Weingart, Lancaster, and Davis are all good references and readily available. I don't have Shimizu's FAST at hand but understand he has covered the subject also.

You'll have to catch me first!

Actually Don, the serious published work begins with Maxwell. Öztap is the first really decent treatment of the subject in English, and he was followed up directly by the articles in Pyrotechnica I mention plus a few things in American Fireworks News and the Bulletin of the Pyrotechnics Guild International. Weingart, Davis, and Lancaster are pretty much silent on the subject as is Shimizu. Well, Shimizu describes the phenomenon of whistling but does not take it to the level of rocket motor building. Öztap goes straight to it, as does Ms Partin. Hardt covers BP rockets well, but only mentions whistling rockets briefly without describing manufacture. The first good description in English of a reasonably safe, well-functioning whistle rocket is B. Vreyen's article, "Screaming Rockets," that was published in Bulletin of the Pyrotechnics Guild International #70, May 1990. Prior to this whistling rocket seen were in the main pretty anemic, incapable of lifting much payload for the most part. The introduction of Öztap type formulations such as Vreyen's "Red Rocket Mix" marked a major step forward in the technology of whistling rocket making in the US. These formulations allowed for core burning motors that were much less succesptible ti CATO as well as less subject to hygroscopicity-induced propellant degradation.

Another intersting variation on the whistling rocket is the so-called strobe rocket which produces a pulsating bright light as it ascends. These are also described in the pyrotechnic literature. The strobe rockets are still more difficult to produce and launch successfully than are the whistling rockets.

Kory Kline flew a rocket at Lucerne (early-mid '80s, I believe) with party horns glued to the fin tips. Liftoff was so fast and loud that you couldn't hear anything. We quietly listened as the model silently coasted, then suddenly we could hear what sounded like a chorus of cows. Very amusing!

-- Ross Hironaka

Might have worked better with an E6 or Estes E9.

You could intentionally have it work on the downleg with deployed air brakes so terminal velocity was perect for the wistles/horns.

Just tech Jerry who was there for the Kline flight Ross cites.

My impression was that the liftoff was so fast that the reeds in the plastic party horns were "stuck." Once the bird slowed to the ideal velocity, the horns started making noise. Unfortunately, it was so high up by then that the noise wasn't very loud to us on the range.

A long burn relatively quiet E6 would be interesting, if you can hear the horn above the engine thrust. If one could tailor the speed to produce a musical tune, that would be pretty cool. Or maybe shoot for fairly constant speed and vary the geometry of the wind instrument. I'm thinking the opening riffs to "Purple Haze" or maybe that annoying melody from "Close Encounters."

My 13 mm Rotorocs with (3) 1/4" holes punched in the top usually produced 3 tones in succession just before apogee. (High pitch, medium pitch, low pitch.) That made it all the more fun to fly.

Whistling on the return trip sounds interesting -- no competing with motor noise. I like the airbrake idea! Make 'em adjustable so you can dial them in.

-- Ross

I've been following this thread and now that I've heard a few good ideas and a few not so good ideas I figure it's about time to chime in. I've built three of these and my students have built a couple too. Some worked a whole lot better than others. The best of the non-pyrotechnical ones used the whistles from a nerf football kind thing. It whistled at very slow velocities well up into the 2-300 fps range. The kids mounted three of these, one on each fin tip. The rocket was a Fat Boy IIRC and it was powered by a cluster of C6-7s. It made pretty good noise right up until deployment. Second best was a design that featured whistles mounted to two sides of the BT. A cowl was made form card stock to duct the airflow into the whistles. This was pretty good too but not nearly so loud as the first method. When on my own and flying in Idaho over Christmas break a few years ago, I did a salute to Rocketvision. One rocket was a Machbuster of a G55 with a strobe in the nose. I sent this up from a 9,000 foot peak overlooking Yellowstone and the Targhee National forest just outside of Island Park. It went up at midnight into a moonless and cloudless sky. Abso-freaken-lutely breathtaking. Several feet of packed snow on the ground, absolute silence, -25 below zero, had to take snow machines to get up there. But I digress. The other, was launched a little later that night from the cabin out over Henry's Lake. It was based on an Estes Super Big Bertha. The standard D engine mount was swapped out and replaced with a 29mm mount. Surrounding the G80 main motor were three "Whistling Petes" courtesy of the Moapo Indian reservation just outside of Vegas. The whistlers were ignited by the exhaust from the G80. The sound lasted well beyond apogee and could be heard all across the lake. Shoot, the exhaust stream was all sparky and wild too as it trailed behind for about 6-8 feet. It looked like a comet streaking across the sky. This was obviously a violation of the rules and I don't recommend it as policy but with 6 feet of snow on the ground and a couple of miles of frozen lake to fly over I didn't see any big harm. Again, it was a night launch and it looked and sounded spectacular. The sound reverberated all through the valley. Now, it somebody got the Chicoms to make rocket motors for us and get them certified, I'll bet they could make some effects boosters that whistles. I seem to recall some smoke effect motors back in the early 70s. Does anyone else remember these? Any way, that's my $.02.

I have read so much stuff over the years that the original source of information is often unremembered. I know that in one or another of my books, or one or another of the articles in journals, or posts by Haarmann et al, or pages on the net, I learned how to successfully make and fuse first a straight whistle then whistling rocket. I just looked in Hardt and the book has two separate sections concerning pyrotechnic whistles, both with formula, in chapters 15 and 21. Davis is sparing to the point of not being very useful, Weingart the same, and I didn't look in Rev. Lancaster's book at all. So. Just where did my information about whistles and whistling rockets come from? Aha. A bit here and a bit there I have to concede. So I did a quick and dirty on google.

Google IS your friend.

HeH!

Have made two whistling rockets.

2 used a wooden train whistle as a nose cone. Whistled very well, changed pitch with acceleration, but also quit above about 300 fps. Still have the nose cone, but the fin can and body bought it in an F21 cato.

Bob Ellis

I believe some or not all whistling fireworks burn picric acid, not black powder. Rob Brigham Robert Brigham NAR 79579 L1

Words are your friends. Choose them carefully.

How about those wacky Widowmakers? They made a pretty cool sound.

"The Sparks Family" wrote in news:7Aivb.2966$kl6.1760@fed1read03:

Well, contradictory to whistling on the way up it might be neat to somehow mount whistles on a rotary recovery? I would think that the Doppler shift as they spin around would make a pretty cool sound :)