Mar 8 update Whistler---Mimi and Nerf Football Whistles

Won't even bother to post the video (kind of dark, as launched at sunset to wait for winds to die down, and didn't work anyway)
A8-3.
Estimated altitude 80-100 feet, near apogee ejection. Arrow straight boost.
No whistle audible.
I had expected the tail attached shock cord to allow a nose down descent of the body and tail of the rocket (the nose cone obviously attached to shock cord) but the descent was more a tumble recovery rather than ballistic slowed by tail attached streamer as intended--- so no opportunity to achieve air flow on descent.

Broke a fin on landing.

Hmmm, so lessons learned.
Maaaaybeee I need a bigger engine to get it up to speed, possible that didn't reach high enough velocity on ascent to whistle.

Regarding whistle on descent---- balance is achieve a fast enough speed to get air flow over the whistle and still be slow enough to safely recover/impact on the ground.

Idea (and this is so far outside the box you can't even see the box). It is partly modeled on my "Hail Mary" with the Nerf (non-whistling) football

Tennis ball nose cone.
Two shock cords, one 20 feet long attaching tennis ball nose cone to inside of body tube of rocket.
Second attached to a small chute attached to tail of rocket, so on descent, from down to up, you have
tennis ball
long shock cord
rocket
short shock cord
small BUT VERY tough parachute
(issue already is tangling of shock cords)
Whistle inlet is inside the body tube, with the vent outside the body tube.

BTW, from what I have found googling terminal velocity of a tennis ball, comes out to 21.5 m/s or about 50 mph. Compares to commercial tennis ball launchers (I guess for practice at Tennis Clubs) at beginner to intermediate level of 20-70 mph.

Standard rocket on ascent (no whistle expected)
on Descent, the heavy tennis ball (68 grams) leads and drags the rocket down at moderate speed, slowed only slightly by the chute. Perhaps enough speed to blow the whistle
At impact 1 (tennis ball) the BALL is no longer part of the rocket mass, so the chute is ONLY slowing the rocket body and tail (and whistle) at that point. So should START slowing that part of the rocket very quickly (still not sure how much you can get in only 20 feet, though).

Anyway, Thomas, you are up, let's see how your flights go.

Tom

Well, no audible whistle on flight 2 on C6-3. Not sure if I am not generating enough pressure through the funnel or if the draft over the entire whistle is blowing away the sound. Open for ideas.

Still got an arrow straight boost and a safe recovery.

Just to add to the 'did not work' data pile. I relieved material on two fins of my Thumper and epoxied a sport whistle in with slightly enlarged and smoothed mouth inlets into fins, hoping to benefit from some laminar flow. Major 'I' motor anomaly and got no chute. We all agreed any whistle at terminal velocity was due to the 'bumps on the fins' and 'big butt' syndrome-not the whistle itself. It would have been more realistic if was a V-2....

Whistler from a Nerf football used on a Big Daddy. Cannot hear it during boost, but after boost a whistle can be herd to apogee.

Mightyrocketman said:

Whistler from a Nerf football used on a Big Daddy. Cannot hear it during boost, but after boost a whistle can be herd to apogee.


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Is that the whistle from the Nerf Vortex Howler?

I believe so. I bought the football back in the 1990's. The football had three whistles and a finned tail.


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On my 4-D12 powered B-day rocket I mounted 3 Party Sirens to the fin tips along with my 6 plastic whistles. You Could NOT hear a sound other then then roar of the motors. Did get all three party poppers to deploy streamers and confetti along with the models 30" hemi chute but Not a single sound could be heard in person or on the tape.

This model took off like a scalded duck I'm thinking more then enough air flow, just too much external noise for the Whistles or sirens to be heard.

Updates:
One of our number was kind enough to send me 4 whistles from a Screaming MiMi. They are good quality what I call "Whizzlers", they make a high pitched almost "siren" sound that varies depending on how hard you blow. While they seem loud when blown in a room, I can see how they would easily be drowned out by a rocket engine. ALSO, while they have a little bit of a "cone" like inlet, still doubt that standard rocket velocities would force enough air THROUGH the center to flow these.
May try Thomas's "country wind tunnel" and hold them out the window of the car. I still wonder with ANY type of whistle whether the air streaming rushing AROUND the whistle affects/suppresses the sound of the whistle.

Also bought a Nerf Vortex Football. It comes with 3 attached/embedded plastic whistles. You DO hear a whistle when you through it, and it is fairly similar to the ones in the movies from dropping bombs. Discussed this with my Dad, a retired AF Nav/Bombardier, dropped bombs B-26's, B-57's, and B-58's. Never heard a bomb whistle. I digress. The Vortex whistle is distinct and cool, but not very loud, and you'd never hear it over an engine.
I may consider a design that sticks the Vortex football into my "Hail Mary" football launcher. You WOULD be able to hear the whistle on descent, and you could actually CATCH the football. The football weighs 130 grams. The fins do not quite fit into a Pringles can, so I will probably have to roll my own body tube. Should still be able to stay way under max lift off weight for a D engine. Still will also probably put a long pink streamer on it just for localization purposes, as if the rocket weathercocks or otherwise deviates from optimal flight path, may not be easy to find the football on the ground.

My neighbor bought a 3 pack of these with what looks like similar whistles on the football, (not visible in photo) at Walmart. Granted, they are mounted on the foam nose cone at what appears to be around a 10-20* angle away from the body tube. Given my best guesstimation, a 13mm motor might just fit in this sling shot rocket. My real thoughts are, figuring out the true angle of that nose on the toy and applying it to mounting said whistles on a LPR rocket that you built with balance for a motor. Cheaper than the football and you get 3 whistles.

I have a Screaming Mimi that I built with my daughter about a decade ago, and I do recall a decent whistle on the couple launches we used it - unfortunately one of the tubes with the whistle broke off and it's been gathering dust until now - just ordered a few "siren type whistles off of amazon and going to experiment to see if I can get something working. A decade later and a 6-year old son is a great excuse to get back into the hobby.

If it's any consolation, I flew my Whizzler at Freedom Launch last weekend, and got no joy. Partly due to the "less than Avant-garde performance."
Video HERE[video]https://s343.photobucket.com/user/glbyrum/media/Wizzler_zpscd26fd93.mp4.html?filters[user]=75504036&filters[recent]=1&sort=1&o=3[/video]. The whistles never had a chance. I have loaded the nose cone with 1 oz of bird shot + adequate epoxy to level the stability. I hope I got it right. Maybe at the next ROSCO launch?

I have been following both of these threads. One I call the "Whistler (conventional whistle)" and the other the "Whizzler (siren whistle)". I tend to think that there is more than enough volumetric flowrate for either kind of whistle. If you just think of a stream tube 1 inch in diameter sweeping out a volume of air in front of it moving at 288 fps (or 196 mph), you will find that there will be a high volumetric flowrate. For example,

Vdot = cross-sectional area x velocity = pi * (D^2) * V = 3.14 x (1^2) x 288 x (1 sq.ft./144 sq. in.) = 1.57 cu.ft./sec.

I think that is more air than most humans can blow into a whistle. So, the problem is probably getting a high enough velocity to get a good pressure drop and, of course, making a whistle sound that can be heard over the rocket motor. Some people say they can hear the whistle and some say they can't. Some they hear the whistle after the boost, which I take to mean after the motor burn. There are a large number of reports on Rocket Reviews (the old EMRR) as follow:

https://www.rocketreviews.com/estes-screamin-mimi-andy-miller.html

https://www.rocketreviews.com/estes-screamin-max-j-stuart-powley.html

There *are* some rather quiet motors. The Aerotech 24mm "D" reloads are more of a loud hiss than a roar...

aerostadt said:

Vdot = cross-sectional area x velocity = pi * (D^2) * V = 3.14 x (1^2) x 288 x (1 sq.ft./144 sq. in.) = 1.57 cu.ft./sec.
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I may be wrong, but I believe the equation assumes the air that hits the front ofmthe scoop actually goes through the whistle. I have read that longer tube fins stop acting like fins and start acting like solid blocked cylinders where most if not all the air just bounces off the opening and goes down the outer sides. I suspect this could even be more so with the resistance generated from the standard and siren whistles.

Regarding the motor sound obscuring the whistle, I am embarrassed I haven't already thought of and tried a simple test. How high is the rocket at peak velocity? Maybe 100 feet or less above the rod? If you are launching the rocket, have someone stand 100 feet past the pad from you, and have them blow the same whistle while you launch a standard rocket with the same engine you'd use for your whistle rocket. If you can't hear it over the engine noise, that is probably your answer.

A factor for MY regular coach type whistle failure may also be that the high velocity airflow over the VENT/OUTLET of the whistle during launch may be obscuring or distorting the vibrations. If you put your finger over the vent while blowing such a whistle (not PLUGGING it but just diverting it) the sound goes away. Not sure if this is the case for the siren/Mimi whistle, as some people as described in your links have successfully heard the whistle. The Nerf Howler whistle certainly makes sound in flight, although it is not a loud piercing whistle and the velocities achieved are probably less than rocket launch velocities. While faster may be louder, the relationship may not be liner at at some point excess velocity may obscure the sound.

I think that blowing into a whistle has more velocity than anyone thinks. A common sneeze is 600mph!
Can't say for everyone, but barely blowing into a whistle provides little action, your really gotta blow.
Air deflected at the nose cone reduces air flow down the sides as I understand.
My idea is to capture that focused air coming off the nose cone and funel it into shaped body tubes around the whistle and force it faster into it.
I still don't think it will be enough without an engine so load you couldn't hear it anyways.
But maybe there is a different kind of whistle that produces more db's at a lower volumn of air.
Back to Bing, the search is on....going!

Didn't take long, check this out. Looks light and with a clip.
https://www.bestglide.com/nato_distress_whistle.html

I just got back from the Latest ROSCO launch, and I gave my Whizzler it's 2nd chance. I put an oz of weight, + epoxy, in the nose cone to stabilize it because it curly cued about 30' in the air. It flew perfect this time, but the whistles didn't sound off, or we just couldn't hear them. Video to follow.