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Engine Chorus

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The sound of a supercar is one of its main attractions.

I propose a W-type engine arrangement, where each V has a separate crankshaft and is separately geared in such a way that one side runs at a slightly different RPM to the other.

This would cost more, weigh more and probably be detrimental to performance. However, we would essentially have dual oscillators as our sound source, and as anyone who has played with a synthesizer can testify, more oscillators means a thicker, more lustrous sound.

With sufficient gearing between them you could adjust the detuning.

mitxela, May 06 2014

what it possibly could sound like http://mitxela.com/...eo/engineChorus.mp3
A clip from Ayrton Senna's 1992 Honda V12, it plays the original, then detuned 0.1%, then 20% (about four semitones). [mitxela, May 08 2014]

Karlheinz Stockhausen http://en.wikipedia...rlheinz_Stockhausen
Not the most "accessible" of composers ... [8th of 7, May 08 2014]

F1 CVT http://www.f1fanati...e-transmission-cvt/
[bs0u0155, May 09 2014]

Trombone_20Exhaust [spidermother, May 09 2014]

[link]






       [+] lol.
FlyingToaster, May 06 2014
  

       [+] nice! Made me think of another idea, related, but maybe already baked? Yes, baked a millions times, so added, deleted, moving along.
sophocles, May 06 2014
  

       oh, very nice. I imagine this as having two manual gear boxes (already super complex and cool). Using these you could alter the interval between the two. So I could drive around making a power chord or maybe a diminished fourth.
bs0u0155, May 06 2014
  

       Oooh - this means that your car could sound like a Wellington bomber.   

       You'd need a finely variable, rather than fixed, gearing between the two halves, so that the sounds can drift through their phase changes at varying rates.   

       [+]
MaxwellBuchanan, May 06 2014
  

       Why not have two V8 engines, one driving each rear wheel? It means you can dispense with a differential which should prove a saving in weight and complexity.   

       That would give you your phase drift as you turn in and out of corners; the subtle difference between tyres would add to the interest.
pocmloc, May 06 2014
  

       //can dispense with a differential which should prove a saving in weight and complexity//   

       Absolutely, throw out that differential, complex maintenance hungry thing. Just get in another engine, and gearbox!!
bs0u0155, May 06 2014
  

       What [FlyingToaster] said.
Voice, May 06 2014
  

       Could something similar be achieved with a trombone-style adjustable twin exhaust system?
EnochLives, May 07 2014
  

       Or perhaps each piston could be connected to the crankshaft via its own gearbox?
hippo, May 07 2014
  

       Yes, definitely. Ordinarily I'm not a fan of CVTs, but they could be useful here if you had a manually controlled CVT for each engine. I assume you would want separate throttle control as well. Maybe the gas pedal can operate both in parallel when it is pushed down, but respond to sideways pressure or something to apply more power to one engine or the other. Of course you'll want a trim adjustment as well so you can adjust the default power balance.
scad mientist, May 07 2014
  

       The problem with using CVTs of course is the wellington bomber effect as [Max] said. Some people might find fixed harmonics to be more pleasing. Run the engines with a selectable gear ratio of 2:3, 3:4, 4:5, 5:6, 6:7 and 7:8 between them, then put the output of the two through your standard gearbox and transmission.   

       Okay, now I want to know what that would sound like, but I don't have time to find some engine sounds, adjust the timing and mix them.
scad mientist, May 07 2014
  

       You'd probably have a horrendous beat that would be difficult to prevent from destroying things over time. Vibrations are generally bad things for engines, mounts, etc, despite how they sound.
RayfordSteele, May 07 2014
  

       // your car could sound like a Wellington bomber. //   

       Wellington good (2 x Merlin X), Lancaster better (4 x Merlin XXIV) ...   

       [+]
8th of 7, May 07 2014
  

       //Vibrations are generally bad for engines// The added(/subtracted) vibrations take place outside the engine, wherever you've got the exhausts linked together, or outside the vehicle entirely if they're totally separate exhausts.   

       There should be a partial bypass of the exhausts, that join up and go through a resonator(s) tuned to (a multiple of) the beating frequency.
FlyingToaster, May 07 2014
  

       Yes, a CVT between them would be ideal. There has probably never been a better use for a CVT.   

       //trombone-style adjustable twin exhaust system// Ha! - that almost warrants its own idea. Interestingly the flared end of brass instruments has a huge effect on the harmonic spectrum, it "fills in" the missing overtones. I wonder what it would do to an engine, or indeed the eardrums of those nearby.   

       //find some engine sounds, adjust the timing and mix them// I actually had a go at that when I first thought of this. [link] I'm not convinced it's quite what the real thing would sound like though, as we're detuning everything in the recording, whereas the resonances of the manifolds would be the same... I suppose it comes back to which point the exhausts should mix.
mitxela, May 08 2014
  

       I wonder who has composed and arranged for motor orchestra - a parking lot full of tractors, race cars, motorcycles and weed whackers...
normzone, May 08 2014
  

       Stockhausen would be the first guess.   

       <link>
8th of 7, May 08 2014
  

       A CVT operating under supercar torque loads? Good luck with that...   

       The added / subtracted vibrations are propagated through the driveline, engine mounts, etc. You'd be generally shocked at how much work we put in to mitigating really bad vibrations so that your cars bits don't a: drive your hands crazy through the steering wheel or b: randomly destroy rubber bits like the suspension. Chasing vibrations around a car is like herding cats.
RayfordSteele, May 08 2014
  

       //A CVT operating under supercar torque loads? Good luck with that... //   

       Williams cracked it <link>. F1 cars have supercar levels don't they?
bs0u0155, May 09 2014
  

       But to be fair, it was probably disposable, as are their current gearboxes...
mitxela, May 09 2014
  

       They have to keep them for 6 races, that's 2000 km. That's better than my brother's first car.
bs0u0155, May 09 2014
  

       // Could something similar be achieved with a trombone-style adjustable twin exhaust system?//   

       That would give a different effect; they would enhance existing frequencies rather than alter the fundamental.   

       //20% (about four semitones)//   

       A 20% increase gives a 4:5 ratio; a pleasing interval in its own right, as [scad] said.
spidermother, May 09 2014
  
      
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