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  1. #1
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    Recumbent + electric motor + aerodynamics

    To really get people out of their cars they need to go faster and not be affected by wind so much. There are few things that seem more futile than cycling into a strong headwind. So I thought of an electric motor that could help out at times like that. Also the storage area behind the rider should be aerodynamic. No point spoiling the aero advantage with poorly designed storage. They say aerodynamics is more important behind the rider but it should be easy to have a small front mounted fairing for the chest area. I don't really care about the legs but the chest/torso is bad for aerodynamics and needs to be dealt with.

    Are any designs considering these things I wonder?

  2. #2
    Senior Member delcrossv's Avatar
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    Lowracer + tailbox + bionx electric drive.

    Done.

    Lightning P-38 / M5 M-Racer/Ryan Vanguard

  3. #3
    Senior Member osco53's Avatar
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    This is where I will go,
    I have No real need for speed and IMO Aero below 15 mph is not enough of a concern to warrant the expense.
    I'll take the wind in my face
    With My Delta I can carry a battery set up that will give me long legs and this setup lets me use ALL of my gears so I can use a smaller
    more efficient motor. Hub motors cannot do this....
    e-402.jpg
    Scott Aspect 940 29er, Tour Easy LE, Sun EZ-3 sx, Walmart Thruster :P

  4. #4
    rebmeM roineS JanMM's Avatar
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    Quote Originally Posted by bf2u View Post
    To really get people out of their cars they need to go faster and not be affected by wind so much. There are few things that seem more futile than cycling into a strong headwind. So I thought of an electric motor that could help out at times like that. Also the storage area behind the rider should be aerodynamic. No point spoiling the aero advantage with poorly designed storage. They say aerodynamics is more important behind the rider but it should be easy to have a small front mounted fairing for the chest area. I don't really care about the legs but the chest/torso is bad for aerodynamics and needs to be dealt with.

    Are any designs considering these things I wonder?
    Maybe you should ask over at the Electric Bikes forum......................
    RANS V3 (steel), RANS V-Rex, RANS Screamer

  5. #5
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    Electric is nice for an extra boost on hills too.

  6. #6
    Insane Bicycle Mechanic Jeff Wills's Avatar
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    Quote Originally Posted by bf2u View Post
    To really get people out of their cars they need to go faster and not be affected by wind so much. There are few things that seem more futile than cycling into a strong headwind. So I thought of an electric motor that could help out at times like that. Also the storage area behind the rider should be aerodynamic. No point spoiling the aero advantage with poorly designed storage. They say aerodynamics is more important behind the rider but it should be easy to have a small front mounted fairing for the chest area. I don't really care about the legs but the chest/torso is bad for aerodynamics and needs to be dealt with.

    Are any designs considering these things I wonder?
    Electric assist can be added to any bicycle or similar vehicle. An acquaintance put an electric assist on his Go-One velomobile and used it for a 40 mile round-trip commute:

    Jeff Wills

    All my bikes.

  7. #7
    pan y agua merlinextraligh's Avatar
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    Quote Originally Posted by Jeff Wills View Post
    Electric assist can be added to any bicycle or similar vehicle. An acquaintance put an electric assist on his Go-One velomobile and used it for a 40 mile round-trip commute:
    It seems like a great set up for velomobile, or a fully faired recumbent.

    You get speed with the velomobile from the fairing, but at the cost of weight.

    So add just enough motor and battery to assist acceleration from a stop, and to compensate for the weight climbing, and you've got a very fast, mostly self propelled commuter.
    You could fall off a cliff and die.
    You could get lost and die.
    You could hit a tree and die.
    OR YOU COULD STAY HOME AND FALL OFF THE COUCH AND DIE.

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    Quote Originally Posted by delcrossv View Post
    Lowracer + tailbox + bionx electric drive.

    Done.

    That looks like a work of art. Simply marvelous. Thank you.

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    > My Delta I can carry a battery set up that will give me long legs and this setup lets me use ALL of my gears so I can use a smaller more efficient motor. Hub motors cannot do this....

    Can you explain that for myself and others just starting to learn about ebikes? Why can't you use all the gears with any motor? I've never heard of this limitation before and it sounds very important.

  10. #10
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    Quote Originally Posted by bf2u View Post
    > My Delta I can carry a battery set up that will give me long legs and this setup lets me use ALL of my gears so I can use a smaller more efficient motor. Hub motors cannot do this....

    Can you explain that for myself and others just starting to learn about ebikes? Why can't you use all the gears with any motor? I've never heard of this limitation before and it sounds very important.
    You can use all your gears with hub motors too.

    Motors that installed into the drivetrain make use of the bikes gears, and therefore are more efficient, so you better performance from smaller motors. You're also limited to less powerful motors (~350 watts) because big ones would tear up the drive train. OTOH, hub motors are simpler and cheaper and you can make for the decreased efficiency by increasing power.

  11. #11
    Senior Member osco53's Avatar
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    Quote Originally Posted by bf2u View Post
    > My Delta I can carry a battery set up that will give me long legs and this setup lets me use ALL of my gears so I can use a smaller more efficient motor. Hub motors cannot do this....

    Can you explain that for myself and others just starting to learn about ebikes? Why can't you use all the gears with any motor? I've never heard of this limitation before and it sounds very important.
    Come now,, follow me,, A Hub motor has NO gears,, you hit the go juice button and it pulls or pushes...
    YES YOU can pedal with all your gears but not the hub motor..
    There are lots of posts in various forums about hub motors overheating and thermally shutting down until the temp comes down..
    It may not hurt the motor in the short term but still..
    The motor torque is set up by several factors, one being wheel diameter and that's IT that's all you get,, NO gearing to change that.
    The motors performance window is very narrow

    The EZ-3 Mid motor trike set up I posted the pic of,,,,, look at it..

    You come to a nasty hill,, you down shift and the motor can spin up to its more efficient higher RPM speeds because it is transferring torque
    through your LOWER gears, and will be far less likely to go into a thermal shut down mode...
    You crest the hill, and start shifting, the motor can still assist you now at greater speed.

    There is far more to this,,,
    choice of volts, 36, 48, etc
    type of motor,
    controller,
    battery ratings,
    power cable length, guage,,,,,

    Hub motor advantages,,, far less complexity, weight and cost,
    Mid motor advantages,,, much greater power band, and far greater power options at,,, a greater complexity and cost..

    Two Different worlds. both right but different.

    http://www.electric-bikes.com/betterbikes/index.html

    http://www.electricbike.com/recumbent/ ,,,, This one is a cool write up..

    http://www.recumbents.com/wisil/shumaker/edrive.htm ,,, here is a custom creator,, the detail here is really impressive...

    This rabbit hole goes very deep. and If any of you want to climb down the hole DO YOUR HOMEWORK before you volt up,
    You Got lots to learn... I'm still learning and yet to spend a single penny.
    Its costly and mistakes I cannot afford.
    I do have a background in many things electronic and know just enough to know I'm not ready to build up a system just yet,, I want MID Drive.
    An Important observation, I have ridden my EZ-3 to near 20 mph for very short bursts,
    and an electric set up could easily exceed those speeds,, the trike is NOT up to it. 15 mph is about the top safe speed on my Delta, and I do slow down for corners.
    wheel stress and all that.
    If you want to go fast on three wheels,, you need to move to Tadpoles as they shine at big speeds... Lower CG and all that...
    Cornering a delta at speed could get dicey real fast
    Last edited by osco53; 07-29-13 at 04:08 PM.
    Scott Aspect 940 29er, Tour Easy LE, Sun EZ-3 sx, Walmart Thruster :P

  12. #12
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    Why can't you pedal in all your gears with a hub motor? I think you're confusing overheating the motor with too much throttle and not enough RPMs/speed (on a hill for example), which could/would actually be solved by making use of all your gears.

    Also hub motors come in geared and gearless versions. You'd probably be less likely to encounter overheating problems with a geared version. Geared versions allow the motor to operate at higher RPMs where their are more efficient.
    Last edited by Jimi77; 07-29-13 at 09:36 PM.

  13. #13
    Disco Infiltrator Darth Lefty's Avatar
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    A bicycle is not big or fast enough to run with cars in the 'burbs. A motorcycle is. There is a guy currently (heh) touring around with a fully faired Zero, beating Teslas in cross country races.

    But it's still a bike. No A/C, radio, crumple zones, seat belts, airbags, so on.

  14. #14
    Senior Member osco53's Avatar
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    Quote Originally Posted by Jimi77 View Post
    Why can't you pedal in all your gears with a hub motor? .
    I guess I cannot explain it so you can understand it, last try....

    A hub motor is stitched into the hub,, torque is applied directly to the wheel,,
    there are NO gears unless the hub motor has planetary gears,
    and then the range will still be very limited,, to two ranges I would think.
    Planetary gears add a lot of rotational mass and gear surface resistance,,,
    heat makers often controlled by lubricants,, more resistance...

    But YES you can pedal and shift gears all you like, Still the hub motor will only turn at the wheel/tire RPM...
    So as you start out most HUB motors will not engage/power up until you pedal up to a certain speed say 3 or 5 mph because
    at the WHEEL's RPM below these speeds they cannot produce any useable torque,, all they can do is get hot...

    A mid drive sees the gear you are in,,, so In first gear you spin up a cadence with ease as the mid motor can also do...
    It can reach a applicable rpm and produce thrust/torque that propels the bike forward from a near or complete stop..

    The Motor winds out to its max torque producing Rpm,,, you switch a cassette gear and the motor can spin up again and again
    for the next gear change,, My EZ-3 has 7 gears out back,, that would give me a useable motor torque range 7 times wider than a
    single speed hub motor...

    We are sitting side by side on our Electric recumbent bikes..
    Yours is a 'Hub' system,
    Mine is a 'Mid Drive'
    BOTH our motors are 500 watt rated at 'X' RPM
    Both of us are in 1st gear,
    We are at the base of a 10% grade, already on the grade,
    We push off IN 1st gear, my cadence/RPM of my pedals is the same as your pedal RPM.
    say 27 gear inches for both of us....
    Your Hub motor is in a 700C wheel and rolling many feet for ONE SINGLE RPM,, you have no motor help yet.
    My 'Geared' Mid drive is through my first gear of that 27 gear inches,
    so I have as an example, A MOTOR RPM of 40 to your WHEEL/HUB motor RPM of 1.......
    Your controller will not for safety reasons allow your motor to engage until 40 rpm...
    You got nothing, your grunting up the hill,,,,

    I'm grunting up the same hill with 3 or 400 watts of assist and that is doubling my power output....
    I'm accelerating past 1st gear, now second, now third,,,, By By

    If you cannot understand it this way you need someone far better versed than I to explain it to you..

    You may need basics on Electric motors, RPM, efficiency gearing and Torque.. The Public Library would be a good place to start from..

    or go here and ask:
    http://www.recumbents.com/wisil/whatsup.htm

    the Electric section:
    http://www.recumbents.com/wisil/e-bent/default.htm

    http://www.recumbents.com/wisil/e-be...calculator.asp

    There is nothing wrong about a 'Hub' system as they are about the only ones I see due to the simplicity and cost...
    But I want the Mid drive even though that system is likely to cost THREE times as much...
    Last edited by osco53; 07-30-13 at 06:54 AM.
    Scott Aspect 940 29er, Tour Easy LE, Sun EZ-3 sx, Walmart Thruster :P

  15. #15
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    Quote Originally Posted by osco53 View Post
    I guess I cannot explain it so you can understand it, last try....

    A hub motor is stitched into the hub,, torque is applied directly to the wheel,,
    there are NO gears unless the hub motor has planetary gears,
    and then the range will still be very limited,, to two ranges I would think.
    Planetary gears add a lot of rotational mass and gear surface resistance,,,
    heat makers often controlled by lubricants,, more resistance...

    But YES you can pedal and shift gears all you like, Still the hub motor will only turn at the wheel/tire RPM...
    So as you start out most HUB motors will not engage/power up until you pedal up to a certain speed say 3 or 5 mph because
    at the WHEEL's RPM below these speeds they cannot produce any useable torque,, all they can do is get hot...

    A mid drive sees the gear you are in,,, so In first gear you spin up a cadence with ease as the mid motor can also do...
    It can reach a applicable rpm and produce thrust/torque that propels the bike forward from a near or complete stop..

    The Motor winds out to its max torque producing Rpm,,, you switch a cassette gear and the motor can spin up again and again
    for the next gear change,, My EZ-3 has 7 gears out back,, that would give me a useable motor torque range 7 times wider than a
    single speed hub motor...

    We are sitting side by side on our Electric recumbent bikes..
    Yours is a 'Hub' system,
    Mine is a 'Mid Drive'
    BOTH our motors are 500 watt rated at 'X' RPM
    Both of us are in 1st gear,
    We are at the base of a 10% grade, already on the grade,
    We push off IN 1st gear, my cadence/RPM of my pedals is the same as your pedal RPM.
    say 27 gear inches for both of us....
    Your Hub motor is in a 700C wheel and rolling many feet for ONE SINGLE RPM,, you have no motor help yet.
    My 'Geared' Mid drive is through my first gear of that 27 gear inches,
    so I have as an example, A MOTOR RPM of 40 to your WHEEL/HUB motor RPM of 1.......
    Your controller will not for safety reasons allow your motor to engage until 40 rpm...
    You got nothing, your grunting up the hill,,,,

    I'm grunting up the same hill with 3 or 400 watts of assist and that is doubling my power output....
    I'm accelerating past 1st gear, now second, now third,,,, By By

    If you cannot understand it this way you need someone far better versed than I to explain it to you..

    You may need basics on Electric motors, RPM, efficiency gearing and Torque.. The Public Library would be a good place to start from..

    or go here and ask:
    http://www.recumbents.com/wisil/whatsup.htm

    the Electric section:
    http://www.recumbents.com/wisil/e-bent/default.htm

    http://www.recumbents.com/wisil/e-be...calculator.asp

    There is nothing wrong about a 'Hub' system as they are about the only ones I see due to the simplicity and cost...
    But I want the Mid drive even though that system is likely to cost THREE times as much...
    I understand that shortcoming of HUBs - you posted that "you cannot use all your gears." It would have been more accurate to say the HUB motor doesn't make use of the gears. As far as efficiency goes, I'm more concerned about the "efficiency" of my dollars and would opt for a higher power HUB and bigger battery. If money were no object, then I'd definitely give mid and bb motors more consideration, but my lottery numbers never come up.

  16. #16
    Senior Member osco53's Avatar
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    Yeah, I hear ya Jimi, I should have never got this deep into it, I just assumed people would understand, "you cannot use all your gears." I never dreamed anyone would get hung on that.... my bad.
    The basic concept of a hub motor as a secondary power addition Is separate from the bike's gears, where the Mid drive system better integrates the additional watts into the gear system of the bike...

    As for this way of thinking, "I'm more concerned about the "efficiency" of my dollars and would opt for a higher power HUB and bigger battery" part, That also is viable
    BUT you must then consider the loss of efficiency due to the higher power needs of a larger motor and the additional weight of the larger motor controller and battery.
    Also a larger controller and the larger batteries would be a major portion of the system expense, where the Initial added cost up front of the Mid/gear system is
    most likely all very long lived durable parts, sealed bearings,, short sections of chain and or Inexpensive belts
    For example,, and again this is from data I have read from hobby level EV builders :

    To compare a hub to a mid drive it would take about a 650 watt hub motor to equal the power range of a 500 watt geared mid drive and with the hub you would still have reach 3 to 5 mph before you could benefit from the added watts where the mid drive power would become useful in just a few feet.
    And the bike gearing would allow the mid motor to remain in its power band at far greater speeds.

    It might take a similar amount of amps overall to reach a given speed but again by holding the gear driven system closer to its most efficient rpm the peak amp draw could be held lower enabling the use of smaller less powerful (Less Costly) batteries...

    One of these days I will start my dive into that rabbit hole, It should be fun.....

    Look here,,
    http://www.electric-bikes.com/betterbikes/e4.html ,,,This is dated but still,, a set up for $699.00 plus the battery

    ____________________________________________________________________________

    http://www.bicycleman.com/bionx-elec...ikes/index.htm

    http://www.greenspeed.us/bionx_motor_bike_kit.htm

    $1700 Including battery ??

    Not so much of a difference ya think ??

    Again for some the Hub motor Is the right choice..
    Scott Aspect 940 29er, Tour Easy LE, Sun EZ-3 sx, Walmart Thruster :P

  17. #17
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    The Bionx are pricey IMHO. You can get a 1200-1400 watt crystalyte HUB kit for ~$700. Even the 1900 watt system is only $750.

  18. #18
    Senior Member osco53's Avatar
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    That will be fun to look into, thanks. But 1200-1400 watts ! Wow talk about power.... I want to get into a 500-750 watt system max, I'd like a good 30 mile range with a 36 or 48 volt system. 1200, 1400, and 1900 watt systems would need a rather large fuel tank I would think..
    Scott Aspect 940 29er, Tour Easy LE, Sun EZ-3 sx, Walmart Thruster :P

  19. #19
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    Quote Originally Posted by osco53 View Post
    That will be fun to look into, thanks. But 1200-1400 watts ! Wow talk about power.... I want to get into a 500-750 watt system max, I'd like a good 30 mile range with a 36 or 48 volt system. 1200, 1400, and 1900 watt systems would need a rather large fuel tank I would think..
    Just depends on how much throttle you give them. For a delta trike, a mid-drive motor seems to make the most sense.

  20. #20
    Senior Member PaPa's Avatar
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    Quote Originally Posted by osco53 View Post
    One of these days I will start my dive into that rabbit hole,...
    Indeed, and I suspect you'll learn something too.

    My delta doesn't have the single speed RPM restrictions you allude to, even though the motor is directly coupled to the rear wheel via fixed ratio (just like a geared hub motor). It launches just fine too, if need be, but it's geared for 30 MPH and my legs produce substantially more torque so I don't typically need it or use it below 5 MPH - just no point in it. I also regularly climb 2-4% local grades at 20-25 MPH without a complaint from the motor. The beauty of assist IMO, is that I travel at the city's 25 MPH legal speed limit, take the center of my lane, and never detain traffic. It not only 'feels' safer, but IS safer to match speeds with surrounding traffic.

    The motor is 350w - the batteries are 28v li-ion DeWalt cordless packs in parallel. The bulk of the electronics (including the motor & drive components) was lifted from a Schwinn kick scooter which I purchased at a yard sale. The biggest expense was the batteries & matching charger, about $175.



    Last edited by PaPa; 08-11-13 at 06:00 PM.

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