GoldenMotor.com Forum
General Category => Magic Pie & Smart Pie Discussions => Topic started by: Magzy on May 24, 2011, 05:30:27 AM
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For one reason or another the Magic pie rings like a bell when under load. This attracts unwanted attention. Perceived or real, I know this doesn't bother some of our worldly counterparts but for others in more "jurisdictionally zealous" parts of the world, it's a bit of a concern.
This is an accepted fact of having a Magic pie. And one that is well hidden in the annals of the GM website (i.e. there's no data /info for the noise it makes)
Not one to be defeated in this venture, I'm looking for ways to dampen the electrical pinging noise that attracts unwanted attention from various entities. - Unofficial or otherwise in order to attain a level of stealth that would put the MP into the next level of stealthiest.
So I have embarked on a mini project to remove or dampen the pinging pulses pinging noise that reverberates through the MP housing and makes it ring like a bell.
I'd like to use this thread as a discussion for ideas, development and testing of various solutions so that other MP owners can contribute to and use.
There are a few possible solutions:
Sound absorbing acoustic tiles. http://www.google.com/search?aq=f&sourceid=chrome&ie=UTF-8&q=Sound+Absorbing+Acoustic+Tiles
These are tiles made of foam that trap the resonant waves of sound in the mid to high frequency range (i.e. not bass sounds) which falls into the range of our MP pinging noise. The sound energy is then converted into heat energy where it dissipates.
The trick here is to place this foam in the most advantageous spot on the MP so that the sounds are absorbed in the most efficient manner while absorbing the most sound.
I was thinking inside the motor would be one option but the big issue here it heat. You're effectively insulating all that heat inside the motor and this could spell trouble unless some sort of ventilation is introduced.
The other option is to place foam on the outside of the motor having placed acoustic foam in wheel covers - which would also look cool. see: http://www.google.com/search?um=1&hl=en&safe=active&biw=1263&bih=528&tbm=isch&sa=1&q=polo+bike+wheel+covers&oq=polo+bike+wheel+covers&aq=f&aqi=&aql=&gs_sm=e&gs_upl=9507l10179l0l5l3l0l0l0l2l323l636l3-2
This would also add to the stealth factor because you would not be able to see or hear the motor. If the motor has acoustic tiles on the inside AND outside, then this stealth solution would even put The Predator to shame.
As long as you can manage that heat then this could work.
Time to foam up!
Thoughts?
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I' ve been dabbling with the idea of getting a cheapish wheel cover but i'm not sure whether one will fit over the pie, you may also have to widen the center axle hole in the wheel cover. I guess it would be trial and error. Have you tried fitting a wheel cover?
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Wheel covers can be made from anything reasonably suitable - cardboard works ok - but not when wet.
Plastic is more robust - even cloth, correctly tied on would work.
Carbon fibre would be excellent. These guys www.carbonmods.co.uk do kits to do almost anything with carbon. And quite cheap as well. <$100 worth of materials to build a solid lightweight wheel cover with 5 times the tensile strength of steel at 20% of the weight.
Of course, the holy grail from here would be to create a carbon copy of the Pie Motor housing and stator and then have pie weighing just 1.2 kg instead of 6.somethig kg :P :P :P
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I've always fancied the idea of oil cooling the pie like they do with over clocked pc's.
Just wondered if that would quieten it down.
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Now, is it really the covers themselves that vibrates, or is it the spokes that resonates?!
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Could there be a possibility to spray the inside of the motor housing with rubber coating and a (a relatively thick coating)
Just an idea.
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you can make a cheap wheel disc from a plastic estate agents sign. make a wide cone shape for each side and cable tie to the spokes
Actually, i've just found this...http://youtu.be/IfoAJicjNJc (http://youtu.be/IfoAJicjNJc)
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I like the jet and huumm sound of the pie but I also like the idea of dampening the sound down very much but something tells me that unless a fellow Pie colleague on this forum is an acoustics engineer and can put 'listeners' on the pie while on full throttle and also while under max strain up a hill, then analyse the sound data and come up with a targeted solution - then we might be stabbing in the dark.
Perhaps a noise cancelling device is the future, they are developing these for commercial flights with props rather than jets - it might be neat? :-\
In the meantime the only additional idea I can come up with is to use the extra space in the pie to fill up with those moisture silica control pads you get with electronics when being shipped (things that look like little teabags). That way you could 'seal' the pie in the best sound insulation available and not worry about moisture. :) (but you would have to add the replacement of these to your service routine though)
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I am going to try this! I am not technically inclined so I will see if soundproofing the outside will works first. I can make some wheel covers then use spray adhesive to attach some acoustic foam to them. The wheel covers will work nicely as a skirt guard as well. Make that skirt/coat guard for you guys. ;D
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What we have a female forum member?? Scarce...
Unless you wear a kilt?
I'm pretty sure Gary uses his guard for his cape
;)
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LOL! I am indeed a female member. You guys have been great. I don't feel the least bit out of place (except for the fact that I am terrified at the idea of going more than the legal limit on my bike).
I have the Golden Motor Joy Ebike. It does not have the Magic Pie on it. It has the smaller 36V 500w motor. Overheating probably won't be a problem especially with my usage pattern (moderate hills & slow speeds). But, just in case, how hot is too hot?
What we have a female forum member?? Scarce...
Unless you wear a kilt?
I'm pretty sure Gary uses his guard for his cape
;)
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well I think the general guideline from most of the people I have spoken to is that if its too hot to touch, its too hot....
welcome to the forum ;).....
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Thank you & thank you!
well I think the general guideline from most of the people I have spoken to is that if its too hot to touch, its too hot....
welcome to the forum ;).....
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I just done an ebay purchase of a 1980's wheel disc plastic cover so hopefully I get tell you all soon whether they will fit over the pie
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Get a pink one, or yellow.........police will never notice lol :D
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He should paint them to look like alloy wheels as in the attachment below.
Alan
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I got an idea, take a picture of a normal non pie wheel, then get it printed supersize on your cover....invisible pie :)
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I dare not put a cover on both wheels for fear of getting blown over in windy weather!! :o
A front wheel cover will probably make the steering very dodgy, so that's out too. I will definatley also need to remove the rear brake caliper and modify the wheel cover.... it's not going to fit, is it? :D :D
and it's black not pink, but it does have some 80's graphics on it, dooh, it's going from bad to worse..., but I do like the idea of a vinyl wrap of alloy wheels, perhaps gold ones ;) - lol
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I am starting to think that wheel covers would also hold in the heat :(
Gary
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I am starting to think that wheel covers would also hold in the heat :(
Gary
I'm not worried about that. I think air will still be able to circulate enough, the pie in question has an external motor, heat maybe more of a problem with an internal. I'm more worried about actual fitment than anything else. In my opinion its worth a go. :)
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I am almost done stealthing my bike. I have laced black vinyl wheel covers over the motor made. I am currently sewing battery cover/rear rack case out of the same vinyl. I will post pics when I am done. This is taking way longer than I thought it would. It's been a long time since I sewed.
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I am almost done stealthing my bike. I have laced black vinyl wheel covers over the motor made. I am currently sewing battery cover/rear rack case out of the same vinyl. I will post pics when I am done. This is taking way longer than I thought it would. It's been a long time since I sewed.
That sounds very interesting, I look forward to the pictures.
Gary
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I am almost done stealthing my bike. I have laced black vinyl wheel covers over the motor made. I am currently sewing battery cover/rear rack case out of the same vinyl. I will post pics when I am done. This is taking way longer than I thought it would. It's been a long time since I sewed.
Yes pictures would be great. I'm currently designing a bespoke battery frame bag which I intend to post about very soon :)
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If Philip would kindly get together in Engineering, a capacitor (maybe 3) could be plugged into the power connector to silence the "voice coil" effect in the MP without a loss of power. A filter.
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just get a large pannier :)....works great for me.....since I moved from front to rear pie, all I can hear now is my big apple tyres rollin....great for the countryside ;)
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I ended up using vinyl to make my wheel covers. I still haven't taken pics because the bike was in the shop for a while. I need to get to that soon, I know.
But, I wanted to write this post because the trail by my house is getting really strict with respect to electric bikes. The police have been patrolling the trail (on motorcycles no less!). And, they have posted on Twitter asking the public to turn in anyone with an electric bike on the trail.
This morning, as I road my Joy-Ebike with its panniers and wheel cover concealing any hint of electric power, a lycra-clad road biker road next to me and asked about my wheel cover. I told him it was a wheel cover and that it kept my skirt and dresses from getting caught in my spokes. He said "I just wanted to make sure it wasn't a motor." I looked at him as though he had just started speaking another language (thumb on the throttle the entire time). And, he sped past me.
Looks like my fears were well founded!
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just get a large pannier :)....works great for me.....since I moved from front to rear pie, all I can hear now is my big apple tyres rollin....great for the countryside ;)
I really do need the covers to keep my long skirts and dresses out of the spokes. ;D
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I too have managed to get a wheel cover over my rear pie wheel. I have not had time to put it onto a bike and test it yet but I did have slight fitment problems. The freewheel hub will now only tkae a 5 cog freewheel, when spining the freewheel on the hub the plastic wheel cover seems to amplify it's already loud sound, not helped by purchasing the cheapest of the cheap freewheel for fleabay. the reason that I want a wheekl cover is so I can get rid of having a rear rack and having the battery in a large frame bag.