The front wheel hub of my bicycle is a bit lazy. The rear one is OK, it's got a nifty epicyclic gearbox in it, which is nice. So I want to put the front to better use, I'd say that a dynamo would be a good idea, but it's already been done.
So, an old style mechanical air-raid type siren is effectively a centrifugal fan, with slotted exits. There's often a bit of a horn-style motif to improve the whole direction of the sound control thing. We could use an epicyclic gearbox in the front hub to power such a siren. A cable operated clutch would bring it in and out of operation, otherwise you'd have a constitutive Sirencycle*
This machine could be used to ride around areas that need a good siren-ing. Such as nuclear missile targets, tornado zones or France. Alternatively it could just be a jolly feature to have on your bicycle to enjoy with like- minded chums.
* which I think is near Cheltenham.-- bs0u0155, Aug 20 2014 [xandram], this is as close as I can get Cement_20Truck_20Mu...Ice_20Cream_20Maker [normzone, Aug 21 2014] Gears http://sheldonbrown.com/derailer.htmlI think Sheldon would have liked the HB [bs0u0155, Aug 21 2014] Horror of horrors! It has just occurred to me to wonder whether or not the unique sound of bagpipes might be emulated by your bicycle siren.-- Vernon, Aug 20 2014 You could use it to warn OF imminent bagpipe deployment...-- bs0u0155, Aug 20 2014 No downside.-- bungston, Aug 20 2014 Except for lovelorn men chasing after you in the street attracted to your siren song.-- rcarty, Aug 21 2014 Out of interest, which geared hub are you using, and are you using chain or belt drive? I'm considering upgrading, but I can't get anyone to recommend anything other than a rohloff (at like $2k+).-- Custardguts, Aug 21 2014 // A cable operated clutch // jammed in engaged position 5 km from home at sunset [+]-- piluso, Aug 21 2014 + Can we get an alternate Ice Cream Truck song / siren?-- xandram, Aug 21 2014 //which geared hub are you using//
A 1966 Sturmey Archer 3 speed, with the original chain. Derailleur systems <link>, with all their wibbly- wobbly compromise cogs, are for the sort of weak minded individuals that buy a set of 107 kitchen knives off late night cable TV.
In all seriousness, I hear the new Sturmey Archer stuff is heavy but good.-- bs0u0155, Aug 21 2014 I'm pretty sure Sturmey Archer now do a fixed-gear (i.e. no freewheel) 3-speed hub, for the hipsters.-- hippo, Aug 21 2014 Sturmey Archer is the best. I detest those derrière gear systems. No man or woman needs any more than 3 speeds.-- xenzag, Aug 21 2014 The Shimano Alfine is available in 8 and 11 speed versions. I've not ridden one but a few people at work ride them. Not sure of the price but definitely cheaper than a Rohloff.-- EnochLives, Aug 21 2014 [+] idea, [+] piluso's anno.-- calum, Aug 21 2014 [+] make them mandatory during the French stages of the Tour De France to ensure a bloody good siren-ing.-- DenholmRicshaw, Aug 21 2014 //mandatory during the French stages of the Tour De France to ensure a bloody good siren-ing//
That would be fantastic, imagine the din of a furiously sirening peloton descending an alp.-- bs0u0155, Aug 21 2014 Well, if you are going to use this going downhill in France, the sound of a WWII Stuka siren might be a bit much.
If you built it right, you could use the front forks as the siren horns. The shape is vaguely the same.-- baconbrain, Aug 21 2014 // use ... in France, ... a WWII Stuka siren might be a bit much //
Au contraire, it will just mean the french riders increase their speed to get away ...-- 8th of 7, Aug 22 2014 // french riders increase their speed to get away ...//
which increases the tone and intensity of the siren, which increases the speed further...
A vicious cycle if you will.-- bs0u0155, Aug 22 2014 <applause>-- 8th of 7, Aug 22 2014 <more applause>-- AusCan531, Aug 22 2014 random, halfbakery