cbr250r streamliner sport style

[sendler]

Are your handle bars really clipped on that low?

[bschloop]

they are. the clamps are approximately 1 inch above the bottom triple tree which puts the handlebars themselves even with my knees while riding. I find it horribly uncomfortable to be in a tuck if my hands are up around my head. this allows me to tuck continually without discomfort in my shoulders wrists and elbows.

[bschloop]

So, some of you might have realized that I have a bit of a tendency to change things up quite sporadically at times. This is one of those times. As I was finishing up the right side of my fairing I took a few steps back and realized that what I had made is not only a huge compromise in aerodynamics, it is also already commercially available. I also was recently given an electric bike to play with, and have decided to streamline that as well. My new direction is simple, and much easier to implement and repeat. I have made a plug for a top/bottom piece to be put together into a dustbin type fairing 20" wide, and am going to pull a mold so that I can make multiple fairings. I will also be doing the same for a matching tail piece.

[bschloop]

Jig for shaping foam.

Finished plug ready for smoothing
My "new" e-bike

[Grant-53]

[IMG] http://futuristicnews.com/wp-content...-pauley-02.jpg.[/IMG]
I like the profile of this with a tail like that on low&slow.

[renault_megane_dci]

[/URL]My "new" e-bike

Wow !

Can you tell us more ?
Sounds like a cool story

[sendler]

The electric bike looks like one of these chassis kits from Electric Motorsport.
.
Native GPR-S Electric Motorcycle 72V 300A Developers Chassis with ME0709 and Alltrax AXE7234 - MOTORCYCLES
.

[bschloop]

Originally Posted by sendler

The electric bike looks like one of these chassis kits from Electric Motorsport.
.
Native GPR-S Electric Motorcycle 72V 300A Developers Chassis with ME0709 and Alltrax AXE7234 - MOTORCYCLES
.

That's exactly what it is. I was talking with an associate about my motorcycle projects just after my sr185 died and he mentioned that he knew someone who was trying to get rid of an electric bike. I checked the bike out and found that it had a bad battery due to a short in the charging system. This made me think twice about it as a project due to the high price of advanced batteries, but he didn't want anything for the bike, so I decided this was my best opportunity to test a theory that's been bouncing around the back of my head for quite a while now. The theory goes like this: streamlining allows less power to go faster, but gearing to go faster causes lower acceleration efficiency especially in electric vehicles. Multi speed transmissions allow for lower gearing for acceleration efficiency and higher gearing for cruising efficiency. Therefore a multi speed transmission allows for maximization of efficiency in electric vehicles especially when streamlining is employed.
With this in mind I acquired a lead acid battery pack, and will streamline the electric bike. Then I plan to assemble the 4speed transmission out of my old sr185 into a modular unit that can be easily inserted and removed from the drive train to properly test my theory.

[sendler]

Don't make it more trouble than it is worth. Streamline it and set the final gearing for the top speed that you want and then see how well it takes off from a stop. magazine tester that review the Brahmo always just end up putting it in 3rd or 4th and leaving it without shifting. the Electric Motorsport site is down or I could link the dyno for that motor. The efficiency is high over a large range of rpm.

[bschloop]

This is the performance curve you are referencing.
Unfortunately this curve does not show a wide range of rpm. It shows a steady voltage increasing torque curve for visualization of steady state operation at 48v. The x-axis represents torque not speed. The purple line which represents rpm starts at 3500 and slowly decreases to 3000 as torque increases. The efficiency line on this graph actually is showing us that as load is reduced, motor efficiency also drops because most of the power consumed is being used to overcome the internal friction, conductor resistance, and other such things just to keep the motor spinning. More important to me is the red line which shows that for a given voltage, amperage and therefore wattage will increase proportional to torque. To me this graph shows two things. One: to keep an electric motor in its most efficient operating zone we need to control the load applied. And Two: running at the lowest torque that is inside this range is ideal for keeping amperage low.

Simply running the tallest gearing that the motor can handle might seem intuitive, but it is exactly the opposite. Brammo's problem is that they started with a feasible single reduction gearing and geared down for better accelleration. Whereas if you look at a properly designed transmission, you start with a reduction which allows for acceptable acceleration then gear up to increase top speed. This is why accelerating from a stop in second gear is not practical in any successful production vehicle.