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You make a good point. I'm glad you are looking into just how much it takes to blow these whistles. Just remember, no two are alike. I bought 10 of them and used the three best ones in the bunch. Some of them were really bad, and I suppose that's because there's likely no QC inspection done on them. I'd research your area and see if there is a nearby clown supply warehouse around. It's prolly something you never thought to look for.
 
Gary Byrum said:
You make a good point. I'm glad you are looking into just how much it takes to blow these whistles. Just remember, no two are alike. I bought 10 of them and used the three best ones in the bunch. Some of them were really bad, and I suppose that's because there's likely no QC inspection done on them. I'd research your area and see if there is a nearby clown supply warehouse around. It's prolly something you never thought to look for.
Click to expand...

Gary, I saw on the product reviews yesterday that some people complained that only 2 in 12 of the cheap siren whistles worked, but at about $5 ordered I a dozen anyways. The reviews on the expensive siren whistle were good, so I ordered one of those.
 
aerostadt said:
I went back and edited my last post. It turns out that 1 inch (not 0.1") of water (differential pressure) corresponds to about to about 68.9 fps or roughly 70 fps or about 47 mph. Afterwards I took a piece of clear plastic tubing and put some water in it and bent it in a U-shape fashion and thereby constructed a crude water manometer. I found that with a little bit of effort that I could sustain a differential pressure of about 1 foot by blowing into the tube and holding my breath. (One atmosphere corresponds to about 34.14 ft of water.) One foot of water corresponds to 238.8 fps or almost 163 mph. If I blew impulsively, I could make the water go much higher, actually, blowing water out of the plastic tube. This means that a model rocket might be able to provide enough differential pressure to blow a whistle or whizzle (siren whistle), but it isn't clear, because we don't know exactly what pressure it takes to blow a whistle. (There are 2 good TRF threads on this subject. One by Tom (Babar) and one by Gary. I just ordered some siren whistles. I am thinking of blowing up a balloon and putting it on the whistle. If it makes noise, I could then put the balloon on a manometer and get a measurement. Perhaps, the manometer measurement might indicate if a model rocket can provide enough pressure (or power).

It might be that so much rocket power is needed to make noise from the whistle that the motor itself noise drowns out the whistle as some posts have stated. However, there is the possibility that the tests so far have not been fast enough to get the whistle operating.
Click to expand...

How about a HillBilly Wind Tunnel Test? Take the model and stick it out the window of the car and see if it whistles? Should have done that with mine, but didn't. Mine is no longer in existence.
 
aerostadt said:
Gary, I saw on the product reviews yesterday that some people complained that only 2 in 12 of the cheap siren whistles worked, but at about $5 ordered I a dozen anyways. The reviews on the expensive siren whistle were good, so I ordered one of those.
Click to expand...

I'd be interested in knowing how well the expensive whistle works when you get it and what it cost.
 
If you used a long-delay motor so that the rocket comes down ballistic and pops the recovery system close to the ground, you might hear it on the way down. Use a rear-eject design so that the shock cord doesn't zipper the body tube.
 
I got my siren whistles (whizzles) yesterday. All 12 (about $4 per dozen) of the cheap ones work. One of them does not sound quite right, but essentially works. I would say that they are not real loud. The expensive siren whistle, which had good reviews, cost about $34. I tried the balloon experiment today. I blew up a balloon roughly to about a 6" diameter and let it discharge through a cheap whizzle. It worked. I say that the balloon emptied in about 2 or 3 seconds. This amounts to about 0.03 cu.ft. per second. My calculations on the other TRF thread show that a 1" diameter model rocket moving at 288 fps (196 mph) will provide about 1.57 cu.ft per second. This volumetric flowrate calculation is linear, so traveling at 1/4 this speed or 49 mph produces .39 cu.ft. per second. I don't think that volumetric flowrate is a problem for model rockets.

I then took the balloon and hooked it up my crude water manometer and I got about 7" of water. This pressure corresponds to an air velocity of 182.4 fps or 124.4 mph. This is not the minimum velocity that a model rocket needs to be going to make the siren whistle work. It just means that this velocity should be sufficient to make the whistle work. The minimum velocity could be less. I still need to do the hill billy wind tunnel (or poor man's wind tunnel) test.
 
I did the hill billy wind tunnel (or poor man's wind tunnel) test today with the cheap siren whistle. Somewhere around 26 to 30 mph the blades start to spin and a very slight sound and vibration can be felt. So the threshold is in that range. At 40 mph a noise can be heard and also at 50 mph. I believe the noise is louder at 65 and 70 mph. I am thinking that even at 70 mph it might be possible for a rocket motor to drown out the siren whistle (whizzle).
 
I'll buy that theory. I think we just can't hear them. But you let someone launch a HPR rocket with no whistles, and 3 out of 10 times, you're likely to hear it whistle pretty darn good.
 
Gary,
I decided to build something like the original Estes Screaming Mimi from spare parts in my inventory. The basic idea is to build something light to get up to speed and make noise as soon as possible. So, like you and Estes I have 3 whizzlers.

IMG_2601.jpg

I have made a RocSim9 file, which I am attaching here. I put nose cones on the Whizzle tubesin the simulation to be conservative. The whizzles offer some air resistance, but I don't know how much. I noticed that even though this a minimum diameter model it does not a take very many add-on details to slow it down. Originally, the model was way into being over 300 fps on the maximum velocity, but now it is down to 216 fps max.
 

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  • Whizzle A.rkt
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Here is the RocSim9 graph with an Estes B6 motor. (I had to re-edit this post after looking at the graph carefully.) Inspection shows that the model is only 9 feet altitude when the velocity hits about 90 fps or about 60 mph. This is when the whizzle sound should start to be fairly audible. The flight time is about 0.26 seconds, so the motor is still making noise (total burn-time is 1.4 seconds). So, the whizzle is competing with the motor sound, but it is close to the ground when the whizzle sound starts. At burn-out the model is slightly below the maximum 216 fps, but the model is about 210 feet up and so the sound is farther away. I may try the B6-4 soon.

I have an 18 mm Apogee D10-3 in my inventory, but I don't think that it helps very much. The model reaches a whizzle velocity at about 0.12 seconds and the model has then about 5 feet altitude. The altitude for the whizzle sound source is not significantly different than the 9 feet with the B6 motor and the D10 motor noise is probably louder. In addition the maximum altitude with the D10 is much higher, although, it won't get there because of the 3 second time delay. However, this means the loads at ejection will be high.

View attachment Whizzle A graph.doc
 
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aerostadt said:
Here is the RocSim9 graph ...................
Click to expand...
Just so you know, some us don't use RocSim or OR. Maybe a user friendlier PDF is in order? Hence the caption under my avatar, "OldSchoolDood".

I hope I was on to something with that 'air channeling' idea. Your model incorporates that also.
 
Gary,
I launched the Whizzle A, which is very similar to the Estes Screaming Mimi, today at the September UROC launch. There was 3 of us at the LCO desk and everyone said that they could hear the whistles, but to me it was very faint and think I could only hear it after the motor burned out. Our LPR rack is fairly far away since it can accommodate up to F and maybe G-motors. I would say it is 80 to 100 feet away. Let's assume that the model is 200' overhead when the whistle becomes audible above the motor. This means that the whistle is between 200' and 300' away. I am sure if I had someone blow the whistle about 250' feet away from me, it would sound faint.

IMG_2620.jpg IMG_2618.jpg IMG_2615.jpg IMG_2616.jpg IMG_2617.jpg

I recorded a video with my old Canon PowerShotSd1000, however, since I was afraid that the memory might not handle too much, I did not record too long. The zoom is not very powerful. I think that maybe I hear a whistle in the video, but it does not sound like what I heard at the launch. This is a fairly inexpensive camera, so I am not sure about the accuracy. Add on to this consideration the fact that there was background noise including the club's electrical generator.

[video=youtube;oXDiXVqB1tM]https://www.youtube.com/watch?v=oXDiXVqB1tM&feature=youtu.be[/video]
 
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Well, The Whizzler got a second chance this past weekend. I loaded one ounce of shotgun pellets in the nose with ....eh...1/2 oz of epoxy? Anyhoo, it stabilized the rocket. Made for a purdy flight with a D12, but still no whistle effects. I reckon I can remove those whistles for a different attempt. and keep the the rocket. Prolly have to change the title though. Sho don't do no whistlin'. Here's the video.
https://s343.photobucket.com/user/glbyrum/media/Whizzler Oct 2014_zpsspguppur.mp4.html?filters[user]=75504036&filters[recent]=1&sort=1&o=0

That went nowhere. Try this.

https://s343.photobucket.com/user/glbyrum/media/Whizzler Oct 2014_zpsspguppur.mp4.html?filters[user]=75504036&filters[recent]=1&sort=1&o=0
 
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Looks like, you have to click the "library" tab at the top, go to "recent downloads", and click on the first vid available. WHAT A PIA! YouTube tomorrow(*&^%%()
 
All of a sudden I have this image of a rocket that deploys Whoopee Cushions as an airbag for recovery.

OR

A rocket (named "MOOving) that has a canned Moo device inside... Clearly, this would need to be made by MadCow.

[video=youtube;CN-SpMpxQUU]https://www.youtube.com/watch?v=CN-SpMpxQUU[/video]
 
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Let's see if I can get my new YouTube account to work.

[video=youtube;IRJPDTyrcvU]https://www.youtube.com/watch?v=IRJPDTyrcvU&feature=youtu.be[/video]
 
Whizzler flew well which is an accomplishment. I have reviewed this thread and maybe I missed it. Did you ever try a hillbilly wind tunnel test?
 
BABAR said:
Whizzler flew well which is an accomplishment. I have reviewed this thread and maybe I missed it. Did you ever try a hillbilly wind tunnel test?
Click to expand...

You talkin bout a "string swing"? No. I usually don't have stability issues, so I don't do that. It was suggested though. I just never remember to try it. I did get it stable though.
 
Gary Byrum said:
You talkin bout a "string swing"? No. I usually don't have stability issues, so I don't do that. It was suggested though. I just never remember to try it. I did get it stable though.
Click to expand...

I think what Tom is referring to as the Hill Billy Wind Tunnel test is checking for whistling rather than stability. I reported earlier in this thread that the inexpensive siren whistles start making noise in the 40 mph to 50 mph range. This may very well be within a few feet above the pad and hence close to the listener. The problem is that the listener may be some distance away from the pad and also that 3 whistles in Gary's rocket are competing with the noise from a D-motor. By the time the D-motor burns out the rocket may be high overhead and the whistles are too far away to be heard. I keep wondering if a possible solution might be to use a lot of whistles and use them as tube fins in a stable rocket with the smallest motor possible.
 
The Hillbilly wind tunnel test is indeed for stability purposes. BUT, can you know how fast your rocket is traveling during that test? I think not. You might get to whistle doing it, but what do you compare it to? Bigger motors are only louder, slower motors are...well. slower, and not as loud. I don't think the hillbilly test can prove anything above the sound of the motor. It's a good idea, and it deserves merit, but it's fruitless.
 
Gary Byrum said:
The Hillbilly wind tunnel test is indeed for stability purposes. BUT, can you know how fast your rocket is traveling during that test? I think not. You might get to whistle doing it, but what do you compare it to? Bigger motors are only louder, slower motors are...well. slower, and not as loud. I don't think the hillbilly test can prove anything above the sound of the motor. It's a good idea, and it deserves merit, but it's fruitless.
Click to expand...

Gary,
What I am referring to is basically having the car passenger hold the rocket out the window in the air stream and see if it makes a whistle. I am wondering if the airflow not just THROUGH the whistle but also the air flow around the whistle outlet might have an effect. With a standard whistle you can blow air through it and make a sound, but if you hold something in .the outflow track, even if it doesn't restrict the flow but simple redirects it you can silence the whistle. The idea behind the "hold it out the car window" test is not to compare the loudness to the rocket motor, but to see if some OTHER factor aside from the motor noise is preventing successful effective audibility of the whistle. While it likely doesn't approximate max V of a rocket, I would guess that if you can't hear it out the car window you probably won't hear it on the rocket. Therefore a positive (audible) car test wouldn't guarantee a successful rocket test, but a negative (non-audible) car test would (I think) predict with high probability a negative rocket test. At least that's my SWAG.
Tom
 
Tried the Whizzle A yesterday on a A8-3 at a student class launch. The background noise was quiet, unlike our club launches with an electric generator running. No one heard a whistle.
 
Interesting that this thread resurfaced. It's too bad few to none have had any success with a whistling rocket, and I'd all but given up hope on the project. My neighbor showed me something that might actually work. There's a toy called "Sky Ripperz", little slingshot rockets with whistles on the nose end. These might work if they are angled correctly. Still, it's uncertain that you would hear them over the motor. I missed a chance getting some when Wally World had em on clearance. Here's what they look like.

sky ripperz 1.gif
 
Funny thing to finally find this thread...I launched a Screamin' Mimi June of last year and some people heard the whistles, but I couldn't and I was fairly disappointed in it (note that my launch was the last flight listed for the S'M on the Rocket Reviews flight report for this rocket , which someone had the link to earlier in this post).

Since then I've had a background project to try to make a better whistling rocket. Having read through your thread, many of the same ideas I had came up here and in Babar's post as well (including the Nerf whistles and such). I thought a bunch of Nerf whistles may be the answer, but I still don't think these will come even close to being heard while the rocket motors are thrusting.

Some other ideas I've had (I may try these in the winter when I have more experimenting time):
-Tube fin rocket (like Super Neon) with whizzers in each tube
-Cut-down plastic recorders/flutes on the sides of the rocket.
-whistles on the bottom so that the motor thrust actually pulls air through the whistle (sounds very sketchy, but may be the path to the best way to get whistling under thrust).
-Whistles instead of fins.
-Adding small funnels to each tube on the Screamin' Mimi
-2+ Metal referee whistles inside the nosecone...may be the answer...worth investigating since those are loud enough and also right in the front undisturbed airstream...can also be placed into MP/HP rockets that are previously tested airworthy. :)
 
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