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teddillard
15 May 2011, 1248
https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-snc6/224711_2119096856509_1218396040_32630031_1316755_n .jpg

Styrofoam mold, with saran wrap wrap.

The idea here is to make a prototype with the "moldless" method, if it works well, use that to make a proper mold.

mpipes
15 May 2011, 1314
Tip: since you're using epoxy resin, you can lay up the fiberglass/carbon directly over the styro without melting it. Then if you need the foam removed after the fact you can either carve it out or use acetone or other solvent to eat it from the back side.

You can also use stings like PVA mold release, or even latex paint (house paint) as a protectant over the foam if needed.

If you want to do a real down and dirty plug for a mold, you can use an epoxy based surfacer over styro or polyester primer over urethane foam to fill the voids, sand it smooth til it's slick, apply mold release wax and go to town pulling a mold directly off the foam buck.

ZoomSmith
15 May 2011, 1334
Is this part of your seat or tailsection?

DaveAK
15 May 2011, 1335
Looks like cheese to me.

teddillard
15 May 2011, 1339
Tip: since you're using epoxy resin, you can lay up the fiberglass/carbon directly over the styro without melting it. Then if you need the foam removed after the fact you can either carve it out or use acetone or other solvent to eat it from the back side.

You can also use stings like PVA mold release, or even latex paint (house paint) as a protectant over the foam if needed.

If you want to do a real down and dirty plug for a mold, you can use an epoxy based surfacer over styro or polyester primer over urethane foam to fill the voids, sand it smooth til it's slick, apply mold release wax and go to town pulling a mold directly off the foam buck.

woah. sick. :D


Is this part of your seat or tailsection?

no. :cool:

ZoomSmith
15 May 2011, 1403
no. :cool:

OK, looks great then.:confused:

teddillard
21 May 2011, 0538
It dawned on me I could use the cutout to help mold the piece, once the carbon was down. Here's what that looks like:

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-snc6/247172_2133471055855_1218396040_32648593_3532791_n .jpg

I have plastic wrap tight around it to smooth it and keep it tight, too. Should make it easier to finish. Here's how it looks right now, with a weight on the top flat:

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-snc6/247023_2133471295861_1218396040_32648595_2798974_n .jpg

No doubt about it. 1) this is fun. 2) I gotta get me the right supplies. :D

ZoomSmith
21 May 2011, 0658
Instrument cluster shield?

teddillard
21 May 2011, 0712
Instrument cluster shield?

nope.

:rolleyes:

jpanichella
21 May 2011, 0733
Is it something unrelated to your bike?

Headlight Bucket or something?

teddillard
21 May 2011, 0806
Is it something unrelated to your bike?

Headlight Bucket or something?

Nope, it's def. bike-related. Not headlight bucket, tho.

:eek:

Malcolm
21 May 2011, 0836
Can't resist ... motor cooling air intake?

teddillard
21 May 2011, 0857
Can't resist ... motor cooling air intake?

whatEVER would make you guess THAT? :D (bingo!)

Set up, but not fully hardened and cured yet:

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-snc6/225811_2133821984628_1218396040_32649473_7489282_n .jpg

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash4/227326_2133822224634_1218396040_32649476_1412637_n .jpg

DaveAK
21 May 2011, 0934
Chain guard sprocket cover thingamajig.

Nope, it's an air intake for the motor.

What do I win?

teddillard
21 May 2011, 0947
Just cut it out and tried it on for size. Makes a sweet chain guard too!

teddillard
21 May 2011, 1110
The fitting...

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-snc6/250870_2134110311836_1218396040_32650063_8334643_n .jpg

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash4/247926_2134110671845_1218396040_32650064_1040742_n .jpg

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-snc6/247023_2134110871850_1218396040_32650065_1541329_n .jpg

...needs hardware and some final sanding.

Nuts & Volts
21 May 2011, 1121
very cool, you should sell these as an aftermarket motor part :)

do you plan to add any sort of air filter to make sure pebbles and dirt dont fly in?

teddillard
21 May 2011, 1142
Thanks! It's been in the back of my mind for a while now. John Fiorenza, from Motenergy told me they work great to cool the motor, but the few people that had done this type of thing did have problems when riding in the wet, since it's brushed. Since this bike isn't going to be street-legal anytime soon, I'm not too concerned. I guess if I do go into production I'd have to figure something for that, huh? :D

My next step is going to be to do some airflow tests. My whole theory on this is based on the idea that there is an internal fan, but when you take the cover off the motor on the brush side there's precious little access to anything that resembles air channels. You can kind of see that here:

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash4/247926_2134110671845_1218396040_32650064_1040742_n .jpg

You take the cover off and you get huge open slots on the sides. But here's the problem. Mounted in a bike, with forward speed up, it seems to me that, even with the cover off you're going to get a pretty significant Bernoulli effect. Air is going to be sucked from both sides of the motor, at the very least making the fan pretty ineffectual. Take the cover off, and maybe even more so, I don't know.

I'm going to try doing some tests with smoke in my ad-hoc airtunnel to see what it looks like with the stock cover, without it, and then with the scoop.

mpipes
21 May 2011, 1506
I'd build the scoop to cover the entire end of the motor, then on the front face, cut out slots or rectangles where air can pass, but cover them with pre-filter material which keeps water out. http://www.outerwearsracing.com/ The "bars" between the slots would just lend support for the pre-filter material.

Additionally, carbon fiber has a very high heat transfer rate (higher than aluminum) so if you're into experimenting you could build a carbon finned heatsink for that motor as well.

teddillard
21 May 2011, 1530
you would?

mpipes
21 May 2011, 1849
you would?

Yeah, basically extending the current opening so the motor is fully baffled and so you can attach the pre-filter material without anything getting in the way. Right now the exposed portion of the motor would be in the way if you put any of the filter material over it to keep water and debris out.. or at least it may not look as clean as it could.

teddillard
22 May 2011, 0530
Yeah I guess if that was an issue for me, that would be one way to do it. Looks too much like a condom for my taste, though. :O
(edit: they DO have a circular funnel cover that's 9" dia... hmmmmm. )

OK, I set this up to test the scoop against the stock motor cover. Although the stock cover doesn't generate any Bernoulli effect as I thought it might, the scoop does a significantly better job pushing air into the motor.

<iframe width="480" height="390" src="http://www.youtube.com/embed/U3lQrIg7TPo" frameborder="0" allowfullscreen></iframe>

Nuts & Volts
22 May 2011, 0852
Awesome test setup, gettin sh-it done I like it!

Coninsan
22 May 2011, 0920
I would extend the scoop to cover the whole face of the motor, sorta like this: http://kandn.com/images/l/100-8507.jpg
And fashion a cover facing the other direction, which would then be a chain guard. This setup should ensure that there isn't any positive Bernouli effect on the sprocket side and should (if i remember my aerodynamics right) increase airflow, with the sprocket-face cover drawing out additional air as it passes over the cover. (I can't remember the name of that effect)

harlan
22 May 2011, 0948
Nice job Ted! I like the video too!

teddillard
22 May 2011, 0948
I would extend the scoop to cover the whole face of the motor, sorta like this: http://kandn.com/images/l/100-8507.jpg

you would?

:rolleyes:

I did test the scoop reversed, to see if it developed any significant negative pressure, for that reason. It did not. The vents on the motor are on the outside edges as well, so even if it did draw airflow, it wouldn't be coming from where it needs to. If you know what I mean. I'm not sure I do. :D

However, I do like the looks of this thing as a chain guard too, so maybe I make me another...

Thanks Harlan! You think you can sell em?

ZoomSmith
22 May 2011, 0950
I like it!

DaveAK
22 May 2011, 1011
However, I do like the looks of this thing as a chain guard too, so maybe I make me another...
So both my guesses were right! Twice the prizes! :D

mpipes
22 May 2011, 1855
(I can't remember the name of that effect)

Venturi. :)

teddillard
23 May 2011, 0304
Venturi. :)

No, I think it's still Mr. Bernoulli. The venturi thing is just constriction of a flow:
http://en.wikipedia.org/wiki/Venturi_effect

Bernoulli is what makes an airfoil work, because of deflection. http://en.wikipedia.org/wiki/Bernoulli%27s_principle

But I'm fairly confused. Maybe it's the same thing. I think the Bernoulli Principle is what makes the Venturi Effect happen? Yes. Pretty sure of it. Except that the both use the idea of increased speed of airflow as a result of constriction or deflection. What I was looking for was the vacuum that's created over the top of an orifice...

NOAH. HELP.

...then there are the Kutta–Joukowski guys. Those crazy kids. :D

BaldBruce
23 May 2011, 0609
Coanda-effect. Just blame it on Mr Newton and get it over with........

mpipes
23 May 2011, 0616
It is a part of the Bernoulli principle but Bernoulli couldn't have come up with his idea had it not been for the work of Venturi. And Venturi vacuum generators aren't named after Bernoulli ;)