RC jet sound effect generator project

[FMD]

Hello all, my first thread here.

I am interested in making a small, lightweight noise generator, amp, speaker circuit for a radio-controlled jet. I am hoping to use some of the components from those musical greeting cards if possible.

Does anyone know how to do this? I am a complete newbee to this stuff but am a fast learner with some help.

The plane will carry an 11.1v battery or the device could have an independent power supply if light enough. Here is a photo of the "jet" almost complete.

Any help would be much appreciated.
FMD.

 

[Sceadwian]

The sound of a turbine is pretty distinctive, you'd need variable mixed tone generator that was coupled to the throttle, or people would know it's a fake sound right off the bat unless you were flying with a fixed throttle over a long distance, the eye/ear wouldn't match from people's experience. That'd be a bit of a project to bite off if you don't have a clue as to what you're doing.
Simply playing back a fixed sound over a speaker is not gonna work, especially considering how loud you need it to be at a distance to even know it's there, it'd be a relatively decent amount of the power from your battery pack.

 

[Mr RB]

Yep, getting the volume loud enough is going to be the killer. I guess the speaker has to be enclosed in the body/wings and will only have small holes for the sound to exit but then you will have 20 MPH (30 MPH?) air basting over that surface at a 90' angle.

And then there may be other 'planes flying around nearby with 2-stroke engines and open exhaust pipes.

 

[audioguru]

Why make a fake jet airplane?
Use a real little jet tubine then the noise and smell will be real.

 

[superfrog]

Last time I heard a brushless ducted fan, it sounded very much like miniature turbine.
The only difference is inertia (they can trottle up and down much faster that real turbine) and sound intensity. But as the plane is typically smaller, the illusion is quite good.

 

[FMD]

Here's a little more clarification.

The "jet" is powered by a small pusher prop on a brushless motor mounted on rubber bushings... pretty quiet.

The speaker will be housed within the fuselage but instead of holes to allow sound to pass I was thinking of a taut plastic film over the speaker housing. May even amplify a bit like an acoustic guitar.

As far as the characteristic sound of a real turbine that would be ideal but to sample that and utilize would require a loop... not feasible. So, make a jet sound when you play with your kids. Bet it sounds like static noise that trails off as you run out of breath. The key is the doppler effect as the plane goes by.

So what I am after is noise, small, and simple. Hope this clarifies things a bit. I've been reading about zener diodes, rf noise, etc, but the learning curve is steep.

Thanks,
FMD

 

[FMD]

Why make a fake jet airplane?
Use a real little jet tubine then the noise and smell will be real.

Why use a little jet turbine. Use a real jet fighter. Both are too spendy $$$$!
FMD.

 

[audioguru]

On the internet there is a huge model jet bomber with 8 small jet turbines. It shows it crashing.
Each model jet turbine engine costs as much as a small car.

 

[GJS]

On the internet there is a huge model jet bomber with 8 small jet turbines. It shows it crashing.
Each model jet turbine engine costs as much as a small car.

this?.....

 

[FMD]

That would be tough to lay out that kinda cash and have that happen. Quite a few hours in that build too.

 

[Sceadwian]

Good lord, building that is guaranteed to be end in failure, from the clouds and the sound of the mic buffeting it looks like they shouldn't have been flying that day, too windy.

 

[FMD]

Anyone have an idea on how to generate some noise and pipe it to speaker?

 

[Sceadwian]

FMD, did you not read any of the posts made? You can generate a little noise using a recorder and play it back on a cheap speaker, but to get something that you will hear at a distance when the plane is running will probably require more power than all of your servo's combined. You could try a monoblock amplifier (Google it) and a decent power speaker, but the speaker is likley to weight almost as much as half the plane and throw it's performance right out the window. Basically what you want to do is not practically possible.

 

[FMD]

I read the posts. Believe me this will work and is not without precedent. It is amazing how well sound carries especially if you fly in a dead calm. I could take the greeting card tape it to the plane right now (if it was light outside) and hear Kool and the Gang playing Celebration from 200 feet away. Not quite the effect I am looking for but you get the point. That is running off of a couple of coin batteries.

I found a couple of schematics but I have yet to decipher them and gather components and start soldering. The scope of this little project is not to emulate the Blue Angels flying overhead but add an inexpensive feature to these planes. Thought it might be worth a try.

Thanks,
FMD.

 

[Sceadwian]

No I don't get the point because you're forgetting that it's not the sound carrying well that's why you can hear it, it's the incredible dynamic range of human hearing.

Even a stiff breeze would obliterate the sound you're talking about. The sound levels required to carry over 'typical' conditions and ones where you would expect to hear the turbine roar of a jet require several thousands or tens of thousands of times more power.

 

[FMD]

No I don't get the point because you're forgetting that it's not the sound carrying well that's why you can hear it, it's the incredible dynamic range of human hearing.

Even a stiff breeze would obliterate the sound you're talking about. The sound levels required to carry over 'typical' conditions and ones where you would expect to hear the turbine roar of a jet require several thousands or tens of thousands of times more power.

What? If I can hear it, the sound is carrying.

This discussion has strayed far off track. Even a real plane is difficult to hear under certain conditions. When this device passes by 10 feet from one's ear it will be heard. These planes can travel 60 mph easily. In a fast pass, power off glide, the sound would be cool. I see my error now. I should have kept the application to myself and asked if anyone had some insight into making a noise generating circuit played through a small speaker. period.

Hey, whats the harm in trying.

Do a search for a Benedini sound system for RC planes. This is commercially available but a bit too large, complex for my needs and doesn't require tens of thousand of time more power!

Fellow, I am afraid we may have to agree to disagree.

Thanks,
FMD.

 

[audioguru]

I live 10km from a major international airport. When jets takeoff pointing away from me with their noisy exhaust pointing in my direction I can hear the very low frequency rumble.

A greeting card with its tiny piezo speaker cannot produce any low frequency sounds, just high frequency squeaks. It will not make the sound of a jet airplane.

 

[FMD]

I live 10km from a major international airport. When jets takeoff pointing away from me with their noisy exhaust pointing in my direction I can hear the very low frequency rumble.

A greeting card with its tiny piezo speaker cannot produce any low frequency sounds, just high frequency squeaks. It will not make the sound of a jet airplane.

I am trying to produce some color of noise. Be it pink, white, whatever. That speaker will broadcast that noise. It will be audible from some unknown distance in my application. That is the scope of this project. To think that a small setup like this will sound like a real jet is neither realistic nor the intended goal.

My schematic has the noise generated from two 2N4401 transistors and goes through an LM324 op amp. The schematic shows how the op amp works. It seems with my limited knowledge one could construct this amp using various capacitors and resistors or that it can be purchased. Is that correct?

 

[audioguru]

The LM324 opamp is not a power amp so it cannot drive a normal speaker. It can drive a piezo squeaker at low levels.

 

[FMD]

The LM324 opamp is not a power amp so it cannot drive a normal speaker. It can drive a piezo squeaker at low levels.

Bingo! Now I have to check and see, but i'd bet in that card there is a small board with some type of low voltage amp that drives the speaker. There is also some kinda sound chip too. Well, bypass Kool and the Gang and add the transistors for noise, run to the amp and out the speaker. Does that sound like a way to generate noise? I'm asking cause I don't know. Seems do-able.

If my understanding is correct, these opamp's (what does op stand for?) accept a fairly wide voltage input.

I have about 50 or so grams to play with as long as the weight remains over the cg of the plane. I could double that allowable on larger models.

Thanks,
FMD.