Aerodynamics

[LockH]

Nice looking tri and very stealthy in terms of hiding your electric propulsion, I just never liked them because they take up too much width on the bike track.
Would prefer a recumbent high racer although aerodynamics on that tri would be almost unbeatable without going overboard !

Well, some might suggest maybe we need more/wider bike "tracks"? But unless I have missed my guess, the trike will RULE (for us "seniors" and those "disabled" - I am sorta both).

 

[cal3thousand]

Nice looking tri and very stealthy in terms of hiding your electric propulsion, I just never liked them because they take up too much width on the bike track.
Would prefer a recumbent high racer although aerodynamics on that tri would be almost unbeatable without going overboard !

Well, some might suggest maybe we need more/wider bike "tracks"? But unless I have missed my guess, the trike will RULE (for us "seniors" and those "disabled" - I am sorta both).

Someday I will own a trike. But I'm not old enough

 

[docnjoj]

Nice looking tri and very stealthy in terms of hiding your electric propulsion, I just never liked them because they take up too much width on the bike track.
Would prefer a recumbent high racer although aerodynamics on that tri would be almost unbeatable without going overboard !

Well, some might suggest maybe we need more/wider bike "tracks"? But unless I have missed my guess, the trike will RULE (for us "seniors" and those "disabled" - I am sorta both).

Someday I will own a trike. But I'm not old enough

I'm 69 and probably not old enough too but the trike helps me keep the shiny side up and out of the ER.
otherDoc

 

[LockH]

Yah. My broken trike stands out in the back yard right now (in the snow) on the lawn. Kinda handy having those two back wheels. Pretty much decided to go two front wheels and recumbent (seat sits up w/folding arm rests when vehicle/operator "at rest"). Will need to whip up some sort of "aero" foam-sandwich cover (to compliment the sail.)
L
PS. Na Na! My back basket is bigger than your basket. (Front basket ain't too shabby either.) And in the future, wanna pull a two-wheeled rickshaw w/more baskets, and seats two (think big comfy couch). Going after the downtown/around the harbour etc "tourist market".

 

[made_in_the_alps_legacy]

Did this evaluation recently, assuming a cubic relation between power against aerodynamic drag and speed,
then comparing to electrcial consumption of E-boards from various topics :

seems like the most effective e-boards are the ones of torqueboard and beto_pty:
maybe they are more "aerodynamic" than others... :lol:
of course, there are various noises from measuring method hidden in the values and aerodynamic drag is not the only source of power consumption

 

[LockH]

`Course, some sailors may take a quite different... tack re "aero":
http://electric-powered-bikes.com/blog/electric-bike-conversions/

 

[WASYLBRYTAN]

There is a new invention out there from an outfit called Null Winds. I am in the process of testing my crude home made version of it and initial tests show 5% speed increase and 30% more battery range. I did this with coroplast and duct tape.
This could be the aerodynamic miracle the world is looking for. It can be added to both wheels for virtually no cost. It increases stability in crosswinds. It makes my bike coast further. It creates a slight downforce and increases traction. And it really seems to work. Bill

https://www.facebook.com/photo.php?...65921465.1073741828.100002509115158&type=3&sr

 

[LockH]

Seems a crime to let that free energy get away.

 

[veloman]

There is a new invention out there from an outfit called Null Winds. I am in the process of testing my crude home made version of it and initial tests show 5% speed increase and 30% more battery range. I did this with coroplast and duct tape.
This could be the aerodynamic miracle the world is looking for. It can be added to both wheels for virtually no cost. It increases stability in crosswinds. It makes my bike coast further. It creates a slight downforce and increases traction. And it really seems to work. Bill

https://www.facebook.com/photo.php?...65921465.1073741828.100002509115158&type=3&sr

30% increase in range? I would love to hear that. Can you do some more thorough testing? I've been meaning to build my own as well.

 

[WASYLBRYTAN]

There is a new invention out there from an outfit called Null Winds. I am in the process of testing my crude home made version of it and initial tests show 5% speed increase and 30% more battery range. I did this with coroplast and duct tape.
This could be the aerodynamic miracle the world is looking for. It can be added to both wheels for virtually no cost. It increases stability in crosswinds. It makes my bike coast further. It creates a slight downforce and increases traction. And it really seems to work. Bill

https://www.facebook.com/photo.php?...65921465.1073741828.100002509115158&type=3&sr

30% increase in range? I would love to hear that. Can you do some more thorough testing? I've been meaning to build my own as well.

I'm not kidding. I have trouble believing it myself each time I do it but I get consistent results between 20% and 30% improvement. I have an 8.8 amp hour battery which normally gives me 24 kilometres of range at full power. This has been a constant throughout hundreds of cycles. The first time I did it with my home made wind fairings just on the front wheel I managed 31 kilometres. Now granted, there will always be some variation for wind and conditions but I ride under nearly identical conditions and the same route every day. I consistently get around 30 with the fairings and around 24 without. I hope more people experiment with these because we just may have found the holy grail of e-bike aerodynamics. Bill

 

[amberwolf]

Looks like something easy to check out on CrazyBike2. I could add some side pieces to my existing fenders and see if it affects my Wh/mile at all. I suspect that given the rest of my bike's lack of aero, I won't see much change.

 

[WASYLBRYTAN]

Looks like something easy to check out on CrazyBike2. I could add some side pieces to my existing fenders and see if it affects my Wh/mile at all. I suspect that given the rest of my bike's lack of aero, I won't see much change.

Well, I am sad to report that I have discontinued experiments with wheel fairings because I do not have the skill or dexterity to make a setup which does not rub the wheels. It is hit and miss, when set up correctly they really work but they get out of adjustment easily and rub the spokes or tires which can become dangerous at high speed. I am just not competent to set it up but IT DOES WORK. You are wrong about suspecting there won't be much of a change. Bill

 

[amberwolf]

Well, we'll see. You might wanna go look at hte pics of CrazyBike2 in the more recent posts it's thread (link in my sig), to see why I don't think it'll make much difference to that particular bike.

I'll try it two ways, just in case. The first would be simply "extending" the front fender down on it's sides, rather than right up against the rims as the ones discussed above do in the kickstarter page images.

The second would be to move them inward and downward, so they line up with the rims as pictured on kickstarter, leaving the tire itself exposed (though i won't be removing the fender itself, as I need that to keep debris and the rare wet stuff flying up from the road off of me as I ride).

Also, I can only do the front wheel, as the rear wheel is surrounded by the cargo pods and such, and is also behind the seat and the "fairing" already on the bike's central frame, and it would almost certainly make no difference to the aero of the bike because of that. (previous versions of top-half-of-rear-wheel fairings/fenders have made no difference, either)

I'll do my usual commuting/etc with them in each position for a while, and see if there's any average difference in wh/mile. Since I don't pedal (except sometimes ghost pedalling now that it's hot enough my knees don't hurt as bad doing it) there's no input from me to worry about distorting the results.

I couldn't tell you if there will be any speed difference, as 20MPH is the max speed limit here, and I could already easily exceed that anyway if I had to.

 

[WASYLBRYTAN]

I would love to see your results and for what it's worth, I'll share some of my findings with you. I tried extending the fenders but it is more efficient to place the flaps near the rims, even if the bike has fenders. The flaps should be one eighth to one quarter of an inch from the rim, it's ok if the rear flares out a little more. You should not cover too much of the wheel, just the top one third or so, any more introduces drag. Disk wheels actually introduce as much drag as they do aero so the gains are almost cancelled out because only the top of the wheel needs to be covered. Also, results are sometimes inconsistent because the aero effect is more pronounced as the headwind or speed increases. Contrary to popular belief, upper wheel fairings on the back really do improve effectiveness although in most cases they are harder to put on. Best of luck. Bill

 

[WASYLBRYTAN]

Well, they say you can't keep a good man down and I could not abandon a good idea just because it is difficult to implement. My wheel fairings worked so well when I had them that I missed their performance when they were gone. So I stared at my e-bike for a couple of hours and used my imagination to solve some of the problems I was having. I installed a new set as in the picture; they cost me about $10. in materials to make and the first ride with them was incredible, I could feel them right away. The amount by which they increase the battery range is difficult to pinpoint because they become more effective as the headwind increases. I took 2 separate rides, both with a headwind but the second headwind was twice as strong. Under exactly the same conditions, with and without the fairing, I noticed at least 20% difference in range. The tires seemed to stick to the pavement better, I could coast farther and the bike hardly slowed down when I hit a headwind. Anyone reading this thread, please try these out; they cost almost nothing and they give incredible results. Bill
ps. When people first see a picture of these fairings they immediately imagine that they act as sails in a crosswind. Nothing is further from the truth. They actually improve stability in crosswinds.

 

[veloman]

Great. Thanks for keeping with this. A good way to add mounting points to the forks is with steel clamps with a hole drilled in them for a screw to face out. I use this technique a lot when I don't want to drill or weld onto a frame.

 

[jbalat]

Well, they say you can't keep a good man down and I could not abandon a good idea just because it is difficult to implement. My wheel fairings worked so well when I had them that I missed their performance when they were gone. So I stared at my e-bike for a couple of hours and used my imagination to solve some of the problems I was having. I installed a new set as in the picture; they cost me about $10. in materials to make and the first ride with them was incredible, I could feel them right away. The amount by which they increase the battery range is difficult to pinpoint because they become more effective as the headwind increases. I took 2 separate rides, both with a headwind but the second headwind was twice as strong. Under exactly the same conditions, with and without the fairing, I noticed at least 20% difference in range. The tires seemed to stick to the pavement better, I could coast farther and the bike hardly slowed down when I hit a headwind. Anyone reading this thread, please try these out; they cost almost nothing and they give incredible results. Bill
ps. When people first see a picture of these fairings they immediately imagine that they act as sails in a crosswind. Nothing is further from the truth. They actually improve stability in crosswinds.

Are you able to post some pics and let us know what materials you used. I can 3D print some mounts for the forks and maybe a support that goes over the front of the wheel. I thought about coreflute but may be a bit too flimsy ?

 

[WASYLBRYTAN]

Well, they say you can't keep a good man down and I could not abandon a good idea just because it is difficult to implement. My wheel fairings worked so well when I had them that I missed their performance when they were gone. So I stared at my e-bike for a couple of hours and used my imagination to solve some of the problems I was having. I installed a new set as in the picture; they cost me about $10. in materials to make and the first ride with them was incredible, I could feel them right away. The amount by which they increase the battery range is difficult to pinpoint because they become more effective as the headwind increases. I took 2 separate rides, both with a headwind but the second headwind was twice as strong. Under exactly the same conditions, with and without the fairing, I noticed at least 20% difference in range. The tires seemed to stick to the pavement better, I could coast farther and the bike hardly slowed down when I hit a headwind. Anyone reading this thread, please try these out; they cost almost nothing and they give incredible results. Bill
ps. When people first see a picture of these fairings they immediately imagine that they act as sails in a crosswind. Nothing is further from the truth. They actually improve stability in crosswinds.

Are you able to post some pics and let us know what materials you used. I can 3D print some mounts for the forks and maybe a support that goes over the front of the wheel. I thought about coreflute but may be a bit too flimsy ?

The picture that is here is all there is to it. I bought a roll of 12"x18" aluminum sheeting at Rona, cut the shapes and duct taped them to the sides of the fenders. It took a lot of fooling around to get them into exactly the right position but I finally did it. The front ones were zip-tied to the forks to help hold them in the right position.

My next modification was to tape the base of all the spokes with duct tape on both sides to simulate aero wheels. I wondered what effect this would have so I tried it and it worked so I kept it. The total package gives an amazing performance boost. The exact percentage is difficult to measure because the effect increases with higher speeds or greater headwinds. But there is a definite increase in the range I get from a battery charge. There is also a noticeable boost in top speed and I am able to reach top speed more easily. This mod seems to be a no brainer; I expect everyone will be using it once word spreads of how effective it is. The technology was developed by Garth Magee whose company is called Null Winds. Bill

 

[Miles]

The total package gives an amazing performance boost. The exact percentage is difficult to measure because the effect increases with higher speeds or greater headwinds. But there is a definite increase in the range I get from a battery charge. There is also a noticeable boost in top speed and I am able to reach top speed more easily. This mod seems to be a no brainer; I expect everyone will be using it once word spreads of how effective it is. The technology was developed by Garth Magee whose company is called Null Winds. Bill

I think we need rather more substance than this...........

 

[DrkAngel]

The use of a drop front, basic fender might have just as much, or better, effect.

Consider that, at 30mph, the top potion of a tire is producing 60mph wind resistance.
Especially with a knobby tread, the determent is severe.

The use of a "fairing" covering the top half of the tire and ideally encompassing the front forks should provide a marked aerodynamic advantage.

A similar rear wheel fairing should produce a much less noticeable improvement but will keep the bike looking ... more even?

 

[speedmd]

 

[veloman]

There are rightfully skeptic people. I am open to the idea and will experiment soon. Worst that happens is you spend a bit of time making your bike look funky. I will report my findings when I get to it.

 

[WASYLBRYTAN]

The use of a drop front, basic fender might have just as much, or better, effect.

Consider that, at 30mph, the top potion of a tire is producing 60mph wind resistance.
Especially with a knobby tread, the determent is severe.

The use of a "fairing" covering the top half of the tire and ideally encompassing the front forks should provide a marked aerodynamic advantage.

A similar rear wheel fairing should produce a much less noticeable improvement but will keep the bike looking ... more even?

Fitting the unit to the front wheel was very difficult; I could not cover more of the front wheel without having wheel rub all the time. The way I have it set up is imperfect but it is the best I could do given the layout of my bike and what I had to work with.

Contrary to what you say, my original trial was with a front unit only; when I added the back unit the beneficial effect was doubled. Also, taping the spoke bases to reduce turbulence has a noticeable benefit.

I have found from my experiments that performance cannot be predicted based on how a setup looks in a picture; only actual use of a product will determine its effectiveness. This bike used to have a 350 watt mid drive motor. I recently upgraded to a 450 watt motor with the battery and all other parts remaining the same. The only difference is the addition of the wheel fairings to the 450 watt motor. The laws of physics dictate that battery range should be 22% less with the more powerful motor but in reality my range is 7-8% higher than it used to be. Consequently, I credit the wind fairings with upto a 30% increase in range. Since the fairings cost almost nothing to make, I would consider the improvement to be phenomenal and I think this may end up being the holy grail of e-bike aerodynamics. Top speed is also about 5% higher and acceleration to top speed seems to be faster and easier.

I find that most people scoff at this idea because of how it looks and their own preconceived (expertise) on the subject of aerodynamics. It is their loss that they are unwilling to even try it out. Bill

 

[cal3thousand]

The use of a drop front, basic fender might have just as much, or better, effect.

Consider that, at 30mph, the top potion of a tire is producing 60mph wind resistance.
Especially with a knobby tread, the determent is severe.

The use of a "fairing" covering the top half of the tire and ideally encompassing the front forks should provide a marked aerodynamic advantage.

A similar rear wheel fairing should produce a much less noticeable improvement but will keep the bike looking ... more even?

Fitting the unit to the front wheel was very difficult; I could not cover more of the front wheel without having wheel rub all the time. The way I have it set up is imperfect but it is the best I could do given the layout of my bike and what I had to work with.

Contrary to what you say, my original trial was with a front unit only; when I added the back unit the beneficial effect was doubled. Also, taping the spoke bases to reduce turbulence has a noticeable benefit.

I have found from my experiments that performance cannot be predicted based on how a setup looks in a picture; only actual use of a product will determine its effectiveness. This bike used to have a 350 watt mid drive motor. I recently upgraded to a 450 watt motor with the battery and all other parts remaining the same. The only difference is the addition of the wheel fairings to the 450 watt motor. The laws of physics dictate that battery range should be 22% less with the more powerful motor but in reality my range is 7-8% higher than it used to be. Consequently, I credit the wind fairings with upto a 30% increase in range. Since the fairings cost almost nothing to make, I would consider the improvement to be phenomenal and I think this may end up being the holy grail of e-bike aerodynamics. Top speed is also about 5% higher and acceleration to top speed seems to be faster and easier.

I find that most people scoff at this idea because of how it looks and their own preconceived (expertise) on the subject of aerodynamics. It is their loss that they are unwilling to even try it out. Bill

Thats interesting. Do you have any pictures of your setup? I'm real interested in trying this out.

 

[veloman]

Comparison tests need to keep variables the same. if you change motors or power settings, I would not include those results. Just because you use a higher power motor does NOT mean you are using more power. It's all about the load at speed. You need a Cycle Analyst or watt meter in order to do any real energy consumption testing IMO.