# Aerodynamics and fairings



## frodus (Apr 12, 2008)

what kind of MC is it? that might be a place to start... so we can help.


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## flashedarling (Jun 30, 2008)

frodus said:


> what kind of MC is it? that might be a place to start... so we can help.


Well I have a 1993 Honda CBR600. I haven't started my conversion yet as I bought the bike and then realized I had no money for parts yet  
Here is a picture of it.










I also just wanted to hear general theory and what other people have done to reduce drag.


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## flashedarling (Jun 30, 2008)

Suddenly I had a burst of insight. Much of the drag is due to trailing vortices behind the rider. Even a baggy jacket can catch the wind and slow you down, making tight clothing a must. This is why an enclosed solution is the best. However this is simply not practical and of dubious street legality.

Why not use a hard fiberglass front to break the wind in front of the driver then a soft stretchable "cloak" behind them. In this fashion the resistance is minimized while driving but when stopped can you can stand up. This could be attached with either velcro or snaps for easy removal (no clue on the strength needed to prevent it from being ripped from your shoulders by the wind.) Also in case of crash you so don't get stuck attached to your bike. The only drawbacks is that it

A. May not actually help that much. Or worse gaps between your body and arms may make it act like even MORE of a parachute. 

B. Make you look absolutely ridiculous.

However since being seen will save your life on the road I can see the second one as being a slight bonus. Of course this is just a theoretical at the moment, but it was a revelation


Here is an example of a full body sock made of a stretch aerodynamic material. I would be making a bodysock that only fit behind me.












Although on my bike I wonder if I'd be hunched forward enough for this to help. For reference here is a picture of a guy on a later version of the CBR600 (Although I'm convinced I'm shorter than this guy, my bike is larger under me)


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## frodus (Apr 12, 2008)

why not get fairings for the CBR600?

http://www.airtech-streamlining.com/hondaz/CBR600F21991-94.htm

tons of solutions... at least as a guide. They're not the only ones manufacturing them either.

Great choice on a bike BTW.


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## flashedarling (Jun 30, 2008)

frodus said:


> why not get fairings for the CBR600?
> 
> http://www.airtech-streamlining.com/hondaz/CBR600F21991-94.htm
> 
> ...


It is entirely possible that I may do that. Or at least use them as a guide. The only reasons are that I'm cheap,I'll need to spend at least 400, probably more to get the fairings while I believe I can make my own for less. Also because I'm putting a higher importance on protecting my components from the elements. The ICE can get wet but my batteries and motor really shouldn't. The standard farings have lots of holes for airflow, if I make my own I can entirely enclose my parts so that they are protected from any unexpected rain with any airflow directed to keep my parts from getting wet. I'm planning on using a PMG 132 motor (not a final decision, just what I'm using for my current design) though and have no idea what kind of airflow it requires to stay cool so maybe lots of airholes would be good. Also if I can get the minimum possible drag I don't really care if it looks pretty. 

Another reason is I've got some crazy ideas about custom LED lighting for improved visibility that are easier to enact if I design the fairings myself.

So I'm exploring the options. Besides if you are going to DIY then might as well really DIY.

PS: I've just found out that the PMG-132 runs clockwise instead of CCW. This may make me change my mind as my rests right now on the motor turning CCW.


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## Slodown (Jun 8, 2008)

flashedarling said:


> Why not use a hard fiberglass front to break the wind in front of the driver then a soft stretchable "cloak" behind them. In this fashion the resistance is minimized while driving but when stopped can you can stand up. This could be attached with either velcro or snaps for easy removal (no clue on the strength needed to prevent it from being ripped from your shoulders by the wind.) Also in case of crash you so don't get stuck attached to your bike. The only drawbacks is that it
> 
> A. May not actually help that much. Or worse gaps between your body and arms may make it act like even MORE of a parachute.
> 
> B. Make you look absolutely ridiculous.


 
Evil Kneivel learned early on that Large capes can get you strangled.  That is why he used the smaller midwaist version. 

I understand that you are trying to do a touneau cover as a cheap aero method, but I would recommend following Vetter's styling because he has had 30+ years experience. He starts off with cheap materials first before using the firmer fiberglass. http://www.craigvetter.com/



> Here is an example of a full body sock made of a stretch aerodynamic material. I would be making a bodysock that only fit behind me.


Caption should read: 

I didn't know a condom could stretch that much.

Or, Man testing Elephant condoms.


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## Slodown (Jun 8, 2008)

Some other how-to you might find interesting for fairings and such. I wanted to try the acrylic heatbox.
http://www.ihpva.org/people/tstrike/building/index.htm
http://www.ihpva.org
http://www.bentrideronline.com/


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## frodus (Apr 12, 2008)

> It is entirely possible that I may do that. Or at least use them as a guide. The only reasons are that I'm cheap,I'll need to spend at least 400, probably more to get the fairings while I believe I can make my own for less.


yeah, kinda spendy... i spent over 500 for my full fiberglass fairings I'm installing soon.




> The ICE can get wet but my batteries and motor really shouldn't.


why not? Are you keeping this thing outside long term? If you're riding, its ok to get it a little wet, the water willl spin off and any heat will help it evaporate. Its ok to get it damp, but pouring water on it is not good. Open series motors are used in golf carts and forklifts and are exposed to elements. Batteries shouldn't matter, they're installed in cars, boats, motorcycles and get exposed to tons. I'd be more worried about protecting electronics.




> if I make my own I can entirely enclose my parts so that they are protected from any unexpected rain with any airflow directed to keep my parts from getting wet.


You don't want to fully enclose the motor or controller, they HAVE to breath, they need to be able to shed the excess heat.



> Another reason is I've got some crazy ideas about custom LED lighting for improved visibility that are easier to enact if I design the fairings myself.


Thats a good idea, but you've got to limit it to tail/brake/running lights only. LED's can't be used for headlights, they're just not bright enough. Calculate the candellas from a normal lightbulb, and the candellas from the highest output LED array you can. Its not going to be cheap, or give off as much light.



> PS: I've just found out that the PMG-132 runs clockwise instead of CCW. This may make me change my mind as my rests right now on the motor turning CCW.


On that machine, get a nice sepex or series wound 6.7" motor  Thats what I've got and it kicks some major ass.


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## flashedarling (Jun 30, 2008)

frodus said:


> Thats a good idea, but you've got to limit it to tail/brake/running lights only. LED's can't be used for headlights, they're just not bright enough. Calculate the candellas from a normal lightbulb, and the candellas from the highest output LED array you can. Its not going to be cheap, or give off as much light.


Are you sure about the headlights? According to this website motorcycle headlights range from 1300low-2000high lumens. http://www.ridethatbike.com/NOMAD%20orginal/HEADLIGHT.htm If I use 5 LuxeonStar Endor Rebels http://www.luxeonstar.com/endor-rebel-cool-white-triemitter-435-lumens-700ma-p-179.php that is over 2000 lumens. Also it would be 33watts for highbeams vs 65 whats for highbeams (the lowbeam power is ~18 watts) Granted this would cost around 125 dollars, so the savings don't exactly trade off for the bulb prices. I do think it is possible though, just perhaps not the most practical.



frodus said:


> On that machine, get a nice sepex or series wound 6.7" motor  Thats what I've got and it kicks some major ass.


You really like those motors don't you, this is this second time you recommended them to me. Although they are similar I notice for the same power the PMG-132 gives more power while the Sepex has a higher RPM. I'm not really sold on the Sepex, although if I knew which one was quieter that would help.

Also I'm trying to build a bike to get the same performance as this guy. http://www.evalbum.com/1877 who happens to be using the same parts I'm planning on using. Although if I could get an aerodynamic edge I'd be even happier.


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## frodus (Apr 12, 2008)

for the LED's you also need to regulate the power going into them, or you'll stress them a little. Its not impossible, but it ain't cheap. 

As far as the motor I've got, Yeah, I love it. Not knocking the perm, its a great motor. I've riden several vehicles with the pancake motors in them and they're nice. Mine peaks around 28hp. I'm not sure about sepex.

If you get the right controller you can get regen with the perm, so thats a selling point, but you can get a series for less than the perm... and get more out of it.

I really can't wait to see this bike... it looks like its going to be a fun project. Just take your time, it took me over a year and its still not complete (but it is running). Spend lots of time on the topic of batteries and figuring out what fits in the frame the best. It pays off.


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