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Author Topic: Aerodynamics  (Read 4276 times)

Killroy

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Re: Aerodynamics
« Reply #45 on: October 26, 2015, 11:21:51 AM »

Even though the racing Vetter fairings from the eMoto Racing series are designed more for a tuck, I like the overall size of the tail.  The lack of turret makes it a little easier too.  I would make one a touch higher.

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Doug S

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Re: Aerodynamics
« Reply #46 on: October 26, 2015, 08:22:08 PM »

Thanks to the links in this thread, I have been reading up and have become quite a fan of Vetter and Terry.

That's a big fan club you're joining there.
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Richard230

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Re: Aerodynamics
« Reply #47 on: October 31, 2015, 08:44:48 PM »

I found this photo of a BMW streamliner that was built in the 1930's.  It does a good job of illustrating the design.  But it sure doesn't look very comfortable.    ;)
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Richard's motorcycle collection:  2018 16.6 kWh Zero S, 2020 KTM 390 Duke, 2002 Yamaha FZ1 (FZS1000N) and a 1978 Honda Kick 'N Go Senior.

mrwilsn

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Re: Aerodynamics
« Reply #48 on: October 31, 2015, 10:46:41 PM »

I found this photo of a BMW streamliner that was built in the 1930's.  It does a good job of illustrating the design.  But it sure doesn't look very comfortable.    ;)

Haha...Nice! Looks like a fish swimming through the air  8)
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togo

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Re: Aerodynamics
« Reply #49 on: November 10, 2015, 11:27:39 AM »

...

Here is a dustbin that has a good sized wind screen that allows the use of the stock headlight and turn signals:



where is that dustbin available?
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Killroy

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Erasmo

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Re: Aerodynamics
« Reply #51 on: November 16, 2015, 10:12:30 PM »

I was thinking about the back part today and it's role in the earodynamics. If you had a top case that didn't enlarge your cross section would that be better for the mpg?

Of course it's far from a kammback but maybe it is better than nothing?
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Richard230

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Re: Aerodynamics
« Reply #52 on: November 17, 2015, 04:32:59 AM »

I was thinking about the back part today and it's role in the earodynamics. If you had a top case that didn't enlarge your cross section would that be better for the mpg?

Of course it's far from a kammback but maybe it is better than nothing?

When I went on my 140-mile ride on a single charge last year, I had my 30L Givi top box installed. I did it for just that reason.  It seemed to me like the small top box would improve the aerodynamics of my Zero and I think it did.    :)
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Richard's motorcycle collection:  2018 16.6 kWh Zero S, 2020 KTM 390 Duke, 2002 Yamaha FZ1 (FZS1000N) and a 1978 Honda Kick 'N Go Senior.

Burton

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Re: Aerodynamics
« Reply #53 on: November 17, 2015, 11:17:41 PM »

I have a givi v46 monokey topcase on my bike and I don't think my range has increased by having it on beyond what is advertised.

Now I have a new phone I can properly test this be crouching at 75mph with and without the top case to see what the watt/miles are on the same section of road. But I likely wont get a chance to do this in the next couple of weeks :/
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Erasmo

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Re: Aerodynamics
« Reply #54 on: November 18, 2015, 12:39:44 AM »

Doesn't matter if it takes a bit longer, the fact that you want to test out my brainfart is awesome already.
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Killroy

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Re: Aerodynamics
« Reply #55 on: December 11, 2015, 11:25:11 AM »

Aero Story!

So I have been commuting on my Zero for 5 days and I have noticed something about the aerodynamics of a stock SR.

My commute is from Campbell to Scotts Valley, CA, the home of Zero, but I dont work there.  Its about 21 miles over the SAnta Cruz Mountains and its about a 1600 ft climb.  On the way down I notice that I cant really just cost down, I have to power down at ~60 MPH.  I dont have any bags dragging in the wind and I am small and in a crouch/ minor-tuck and I can't coast. 

When I'm in my year 2000 Insight Hybrid, not only am I coasting, I'm in a low level regeneration mode 60-80% of the way down at the same speed.

So when I am on my Zero, I'm wasting energy going down a steep mountain.  When I am in my car, I'm charging a battery down.  That is how bad the aero is on a stock motorcycle. 

It should be noted that the original Honda Insight is a freak of car and it has kooky wheel skirts and it has one of the best coefficient of drag of all mass production cars. Note that Tesla Model S is very close, looks really good and does not have weird mobile wheel skirts.

The point is that aero on stock motos is a a large burden on the drivetrain. 

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NEW2elec

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Re: Aerodynamics
« Reply #56 on: December 11, 2015, 11:47:18 AM »

Killroy are you sure you don't have your throttle regen >0 or maybe your brakes are rubbing but going down a mountain you shouldn't need to power at all unless you just really want to fly down it.
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mrwilsn

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Re: Aerodynamics
« Reply #57 on: December 11, 2015, 11:56:33 AM »



The point is that aero on stock motos is a a large burden on the drivetrain.

True but don't under estimate momentum.  A motorcycle doesn't weigh nearly as much as a car and as a result will slow down much quicker....especially with regen trying to slow you down.  While better aero will result in less resistance moving through the air, in the down hill test you outlined I think you would see results much closer to a EV car by just packing on a bunch of weight (if you can do it without also significantly increasing drag coefficient).

Sent from my XT1060 using Tapatalk

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Killroy

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Re: Aerodynamics
« Reply #58 on: December 11, 2015, 12:20:15 PM »

So a insight with driver is about 2000 lb, a Zero with rider is ~600 lb.  So, yes a Insight has ~3 times the mass, but the Zero's its frontal cross sectional area is a fraction of the Insight.  If the aerodynamic drag was proportional on both vehicles, then the Zero should be regeneration on the down hill, but the Zero has poor coefficient of drag, and the frontal area is probably not proportionally low, so it takes a hit there too.  The biggest variable is coefficient of drag, not weight. 
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