smthlndr

i heard a sukhoi at a local airfeild and as it was flying it sounded awesome it had a high pitched jet like whistling sound coming from it. you could here it over the engine good. any suggestions to what it may have been and how to make others sound like that?

DSJBEAN

My Feedback: (1)

Isn't that a cool sound, both our 4*60 and 4*40 do that but it's more prominent on my son's 4*60.

visioneer_one

My Feedback: (506)

Could be the sound of air rushing past exposed linkage. My Ultra Stick whistled quite loudly thanks to its 4 servos in the wing.

Could also be that the owner has a set of these installed...

OldRookie

My Feedback: (13)

OK...I'll bite.
What are they?

Greg

smthlndr

i had forgot about these things i want some of them to go on my p51 lazy tiger because it has a .25 on it and is pretty quite. so i think these would sound great!

phayd

Now that I've seen these, the question is do they have a whistle that recreates the pitch of the oil coolers in a corsair?

smthlndr

they sound like a turbine to e if thats what i heard that day. but only louder.

h8w8n

My 4* 60 also whistled. In the bottom of the engine compartment is an oval drain hole. I always thought it was the sound of the airflow over that hole. I never bothered to prove it by putting tape over the hole and seeing if that stopped it.

cabanestrut2002

The sound you can hear is just the air passing over the surfaces of the aircraft, usually most prominent when in rolling manoeuvres.
Most often on aerobatic models and other aerodynamically 'dirty' aircraft.
dan, cornwall, UK
www.rcflyers.fsnet.co.uk

smthlndr

no i seen 2 of the same exact planes flying that day and only one had that sound. the sound your talking about is alot more subtle than this i heard. it sounds like a bomb dropping. i did find out what it was though he has on the belly of it where the nose drops to a scoop in the front he has a free tyrning turbine in it made of plastic. sort of like you find on those party toys you blow in and the whistle.

gelcoat-RCU

My Feedback: (206)

It tickles me to chuckles when I hear this beautiful shistle. I do not know the origin ...but I'm curious for the answer on this one thread.
I have observed many a performance glider doing a high speed pass whislting for joy. It's just music to mine ears.This is a good query.

smthlndr

i have a fourstar 40 and the hole in it is covered and it does'nt whistle at all.

Chris300s

My Feedback: (1)

Both of my Sukhois have made very distinctive sounds because I opened up all of the cowl louvers with a dremel. I think that there are 26 louvers in all and I used them for my cooling exits. Since they are no where near the 3x rule (cooling drag penalty unless the exit is 3 times larger than the inlet) you had a lot of high velocity air getting pushed through little openings.
Skin hinged planes like the Fiberclassics Extra/Giles and S400 pylon racers make similar noises when you roll them because of sharp edges in turbulent air. Sounds like wailing, or tires screeching.
Chris

Grampaw

How about attaching a tube or tubes to a model to make a whistling or humming sound. I remember L-19 pilots in Korea lashing length of small diameter pipes onto the wing strut to have them make whistling sounds in dives. Any musicians here that might shed a little light on perhaps a using a homemade bamboo tube flute?

$ircra$halot

I don't know for sure, but I have several video's that make reference to air screamer sirens. You might try doing a search under that name and see what you come up with. I know the planes in the video that are fitted with these little sirens are loud.
Happy holidays
Garry

visioneer_one

My Feedback: (506)

Whistling sailplanes - that's the sound of air passing over exposed aileron and/or flap linkages.

For example - my old Weston Magic, with its four exposed aileron and flap linkages in the wing, HUGE top-mounted v-tail ball links and old-school RG-15 airfoil is the noisiest sailplane I have ever owned. It is so distinctly loud at speed that I didn't need to call out to other pilots my intent to make a speed run along the ridge - they could hear it coming from 100+ yards away. screeeeeeeeEEEEEEEEEEEEEEEEEeeeeeeeeeee........

OTOH my Mini-Ellipse, with its smooth molded aileron linkage covers, intergrated aileron gapseals and concealed v-tail linkage is the quietest sailplane I own. The thing is so streamlined and silent that you can hear the air being deflected off the control surfaces while maneuvering at speed!

pipercub6

My Feedback: (16)

You can buy a small device that makes the whistling sound of a bomb dropping from one of the hobby outlets. I saw them advertised and will try to find it again and post it. As for your plane doing it the other guys are right. Parasite drag over objects will often produce noises. You didn't say whether it was all the time or only at certain speed/maneuvers. I would be interested to know.

Pipercub6

bokuda

My Feedback: (7)

I had this happen on a Kaos 40. It sounds cool, but I know it takes energy from somewhere to create the sound. I sealed the control surface gaps and it disappeared. The plane flies better now too and I was able to reduce the control surface throws and still get better response.

LoboFlyer

If we are talking full-scale planes, could it possibly have been a turboprop?

jaker

Sounds like the i4c air whistle to me. I have used them and they sound jet turbine like as you described. The large ones are what I have and they sound cool on my 60 size UltraSport at the faster speeds.

Jaker

Deadeye

According to a guy in my club with 20+ years of flying experience, the whistle you hear from the 4* 40 and 60 is caused by the wings' leading edge . Notice they aren't a solid leading edge, but rather formed with sticks. He called that 'turbulation'.

I noticed that the first time I flew my 4* 60. He was right there, and called it 'leading edge turbulators'.

Carlos Murphy

My Feedback: (72)

The whistles are from i4c products. you mount one or one of each under your wing just behing the leeding edge. They come in a high and low tone version. If anyone is going to the Pasadina Trade show this weekend they will have a booth there.

Q-Ball

My Feedback: (1)

Jake and others that have the I4C large whistles..
I just put two on a Shrike this evening.Can't wait to try it.
My only concern is that the Shrike has a LA40.Not real fast but can always put the MVVS 49 on it.
The instructions say that it works between 50 MPH up.I hope I can get the Shrike up to 50 with the LA.

The other thing.If you want different sounds from each one you have to hacksaw one eighth inch off of one of the tail peices.They look like quality,but will have to see when it's in the air.

I used the plastic toy shop sirens.Actually all plastic and it looks like a turbine inside.Worked only fair and just when you make a low pass at full throttle.Otherwise they aren't loud enough.

Good luck
Walt