Do you use an fairing or partial fairing on your ebike, emoped or BSM?

General Discussion about electric bicycles.
donn   10 kW

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Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by donn » Jan 26 2022 12:53pm

BalorNG wrote:
Jan 26 2022 6:24am
Well, this is a good point, but I think your bike is a bit of an overkill. Recumbents most certainly do have a considerable problem with low speed-stability, starting from a stop and climbing *in general*, at least those worthy of the name - but you do not need a moped-like power to overcome them.
I don't need a motor to get off the start, and climb hills, but it sure does help. Those are the principal weak points of a recumbent, and the motor takes them off the list.

But indeed that thing is overkill, for me - my e-recumbent is pretty close to the limit already, for what I'd like to haul up the stairs or whatever, and I like the general feel of riding a bicycle. So that bicycle is a little too much, like typical velo designs are too much. For me, that gets to the question of what kind of fairing would not only improve the aerodynamics, but wouldn't encumber the bicycle too much.

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Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by ebike4healthandfitness » Jan 26 2022 2:04pm

SafeDiscDancing wrote:
Jan 26 2022 10:41am
spinningmagnets wrote:
Jan 26 2022 9:11am
As to fairings, I dont ride fast enough to make them worthwhile. But aero benefits fascinate me...
The Class 1 and Class 2 ebikes were given the 20 mph speed limit so no aerodynamic advantage exists by doing a redesign.

Class 3 at 28 mph starts to see serious wind resistance, so it begins to make sense.

Ideally the Class 3 should have wider rims, fatter stronger tires, better brakes and some moderate aerodynamic advantages to optimize the 28 mph situation.
Aerodynamics at 20 mph still matters for bikes. If you go to the gribble cycling calculator you can see that even for a road bike at 20 mph wind resistance amounts to 142 watts while rolling resistance and drivetrain inefficiency is only 36 watts and 4 watts respectively. So making aerodynamic improvements will still make good reductions in power usage.

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Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by Chalo » Jan 26 2022 2:36pm

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This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

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Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by ebike4healthandfitness » Jan 26 2022 4:29pm

BalorNG wrote:
Jan 24 2022 2:25am

All in all, I *think* that a narrow-ish USS bars, a front fairing that flips up and forward, all like on electrom - but with a true ogive shape and *closed* sides, so it sits *VERY* close to your body when 'deployed' , a *proper* tailbox (large and with angle of convergeance to allow pressure recovery) and a set of wearable plate fairings on your arms so air can be channelled from front fairing to rear fairing w/o irrecoverable vorticity might just work - that in allow fairing peformance which is a significant portion of a true full composite fairing, but without ingrees-egress issues
How would you have closed sides, but not have ingress and egress issues?

Also, with closed sides how are you going to put your feet out when you come to a stop sign?

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Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by tomjasz » Jan 27 2022 2:54am

My Day 6 Joy large will have a winter fairing. Nothing to do with improving efficiency. Frostbite protection in Minnesnowta. -12 this morning. No go on two wheels or without windscreen protection.
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by BalorNG » Jan 27 2022 4:22am

ebike4healthandfitness wrote:
Jan 26 2022 4:29pm
BalorNG wrote:
Jan 24 2022 2:25am

All in all, I *think* that a narrow-ish USS bars, a front fairing that flips up and forward, all like on electrom - but with a true ogive shape and *closed* sides, so it sits *VERY* close to your body when 'deployed' , a *proper* tailbox (large and with angle of convergeance to allow pressure recovery) and a set of wearable plate fairings on your arms so air can be channelled from front fairing to rear fairing w/o irrecoverable vorticity might just work - that in allow fairing peformance which is a significant portion of a true full composite fairing, but without ingrees-egress issues
How would you have closed sides, but not have ingress and egress issues?

Also, with closed sides how are you going to put your feet out when you come to a stop sign?
I'm do not have a 3d model yet, but I mean closed *sides* (as compared to only the 'top') on a fairings that flips up to allow easy entry/exit, with foot holes or even bomb bay doors - this is pretty commmon on streamliners that have at least some practicability.

Interupts in the fairings is first and foremost to allow 'body english' when situation calls for it, I find this extremely important.

Here is a very interesting one, btw:
http://recumbents.com/mars/pages/proj/t ... tzOFS.html

But level of craftmanship that went into producing this and other Tetz bikes is currently above what I can achieve, and I presume level of riding skill that I never will.

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Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by Warren » Jan 29 2022 10:04am

BalorNG wrote:
Jan 27 2022 4:22am
But level of craftmanship that went into producing this and other Tetz bikes is currently above what I can achieve, and I presume level of riding skill that I never will.
Thanks for this trip down memory lane. I met John on an organized ride (maybe a Sea Gull Century?) back in the 1990s. He showed me this left-hand freewheel on his FWD bike.

http://recumbents.com/mars/pages/proj/t ... drive.html

Seeing MARS and WISIL builders' brilliant designs back then was the happiest, and most hopeful time of my life.

http://recumbents.com/wisil/tetz/tetz_obituary.htm

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SafeDiscDancing   10 kW

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Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by SafeDiscDancing » Jan 29 2022 10:48am

tomjasz wrote:
Jan 27 2022 2:54am
Frostbite protection in Minnesnowta. -12 this morning. No go on two wheels or without windscreen protection.
And on an ebike (since this is a website focused on electric bikes) when it drops below freezing all the "sport" batteries stop working.

So everything good for summer in the high performance cells that are powerful and lightweight goes badly.

There is that Russian guy that posts tons of pictures of winter travel in his area and I guess as long as you warm the pack slowly it's okay, but you can't charge a frozen battery without destroying it.

LTO chemistry is great in the cold but it's not much better than lead acid as far as energy density.

Yeah... the entire coupling of extreme cold and aerodynamic designs is a very strong point.

But again... that Russian guy just has the balls to tough out the cold conditions so that's to be respected. :bigthumb:

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Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by ebike4healthandfitness » Jan 29 2022 4:33pm

ebike4healthandfitness wrote:
Jan 19 2022 3:29am
http://www.kreuzotter.de/english/espeed.htm

Using the above calculator with "road bike hands on tops" and changing rider height and weight to 70" and 200 lbs (average height and weight for an American male) I get a power consumption of 685:watts @ 28.0 mph with pedal cadence at 90. When I switch pedal cadence to 1 (it wouldn't let me input 0) only 615 watts is needed to make 28.0 mph.

So the extra drag caused by pedaling 90 rpm on a road bike going 28 mph is 70 watts.

For the "Roadster" it was 940 watts for 28 mph at pedal cadence 1 and 1025 watts for 28 mph at pedal cadence 90. So to he extra drag caused by pedaling 90 rpm on a Roadster going 28 mph is 85 watts.
Besides what I wrote above another thing to consider is Q factor and how extra width from that (in the form of certain mid drives) would increase drag further.

Also, while not related to aerodynamics, the efficiency of the drive train is another thing to consider as most multi speed mid drives use a single chain ring:

https://www.cyclingabout.com/drivetrain ... een-1x-2x/

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Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by tomjasz » Jan 31 2022 4:59am

SafeDiscDancing wrote:
Jan 29 2022 10:48am
tomjasz wrote:
Jan 27 2022 2:54am
Frostbite protection in Minnesnowta. -12 this morning. No go on two wheels or without windscreen protection.
And on an ebike (since this is a website focused on electric bikes) when it drops below freezing all the "sport" batteries stop working.

So everything good for summer in the high performance cells that are powerful and lightweight goes badly.

There is that Russian guy that posts tons of pictures of winter travel in his area and I guess as long as you warm the pack slowly it's okay, but you can't charge a frozen battery without destroying it.

LTO chemistry is great in the cold but it's not much better than lead acid as far as energy density.

Yeah... the entire coupling of extreme cold and aerodynamic designs is a very strong point.

But again... that Russian guy just has the balls to tough out the cold conditions so that's to be respected. :bigthumb:

I’ve ridden through Minnesota winters since 2015. I had several Minnesota customers that commute all winter. A simple set of electric clothing heaters a small battery to power or Buck converter, pack insulation and bobs your uncle.

I’ve worked outdoors most of my working life. From -10F in MN to 115F in the Mojave Desert. It’s just weather…
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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SafeDiscDancing   10 kW

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Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by SafeDiscDancing » Feb 02 2022 10:20am

donn wrote:
Jan 26 2022 12:53pm
I don't need a motor to get off the start, and climb hills, but it sure does help. Those are the principal weak points of a recumbent, and the motor takes them off the list.
Those "outside" our hobby want to see:

- Starting......................Powered.
- Flat Straights.............Pedal Power.
- Hills............................Powered.

But in my opinion we really want:

- Starting......................Powered AND Pedal Power.
- Flat Straights.............Powered.
- Hills............................Powered AND Pedal Power.

---------------------------

In other words the fairings are there so on a flat straight you get some rest before the next hill or stop sign

At least it seems to make sense because aerodynamics dominates over 20 mph to the 28 mph maximum.

What I'm saying is the pedelic throttle idea for Class 3 sort of takes the fun out of cruising around.

----------------------------

Many studies have proven over the decades that short bursts of energy spaced out is better for your health than a low grade grinding along. The endurance type abuse is in the long run bad for you.

And for older people it is worse... old people need a slow warm up then short bursts followed by rest over and over. The resting is more important the older you get.

So if these ebikes are really supposed to be for the health of older people the resting part is helpful.

Plus, the bumps on the road naturally give exercise and assists in balance which for older people is important.

Old people start to lose sense of their body so the bouncing around and adjusting keep older people younger physically and mentally.

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