# Purpose built Recumbent Electric Motorcycle.



## todayican (Jul 31, 2008)

Ok, this idea got its start over at ES but I wanted to post it here as well to get ideas / feedback.

The idea is to build a mostly enclosed recumbent motorcycle capable of highway speeds (70 to 80mph)

Something with a lightweight steel frame, purpose built, room for lots of batteries for a long range version with the "main pack" being carried low in the frame.

The way I have it drawn now it will have room for 172 headways with room for another 172 in an upper compartment.

The plan is to use one of marks motors running at 96 to 108 volts.

Please take a look at my absurdly bad pencil drawing and let me know what you think, with any luck we can get some guys together and build an "open source" solution to going far and fast (and in comfort) on 2 wheels 

p.s. photoshop enhancements would be most welcomed


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## todayican (Jul 31, 2008)

Got the frame started 
tshtrikes.com


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## john818 (Aug 1, 2008)

Love your projects! I've been thinking about recumbent motorcycles myself lately. Can't wait to see how this turns out.

One thing I wonder about with your frame is that there seems to be no triangulation under the seat. Is the tube stiff enough? Won't it flex a lot? I don't know. I'm just asking.


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## Woodsmith (Jun 5, 2008)

Reminds me of the Quasar from the 1970's. I really fancied one of them.


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## todayican (Jul 31, 2008)

Ill do some triangulated cross members under the seat and forward frame.

Curious, if this bike were sitting on the pavement today, and had a top speed of 100mph with a 200 mile range, what would it fetch?


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## kek_63 (Apr 20, 2008)

Well, I know, It would fetch a couple of big speeding tickets for me


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## sunworksco (Sep 8, 2008)

todayican said:


> Ok, this idea got its start over at ES but I wanted to post it here as well to get ideas / feedback.
> 
> The idea is to build a mostly enclosed recumbent motorcycle capable of highway speeds (70 to 80mph)
> 
> ...


Here u go.


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## samborambo (Aug 27, 2008)

todayican said:


> Ok, this idea got its start over at ES but I wanted to post it here as well to get ideas / feedback.
> 
> The idea is to build a mostly enclosed recumbent motorcycle capable of highway speeds (70 to 80mph)
> 
> ...


Motorcycles generally have a pitiful drag coefficient. Your recumbent idea and the extra cowling do help mitigate the frontal area and aspect ratio of the bike by putting the rider "in" the frame. However, that cowling creates a serious problem in strong cross winds. It'll turn the bike into a kite! I discovered this when researching an electric motorcycle conversion a while back and trying to mitigate drag.

eg: Have you ever seen the movie "World's Fastest Indian"? That bike's cowling was perfect for straight line time trials/top speed on a calm day but if it hit a strong cross wind it would topple immediately.

Sam.


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## sunworksco (Sep 8, 2008)

A bike that has a low center center of gravity with the weight of the components and driver low will not be affected by wind.The "The Fastest Indian" was a little top heavy.


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## TomA (Mar 26, 2009)

I like the bike, its a great effort.

Your biggest problem is going to be the practical issue of what you do when you stop. Craig Vetter's enclosed Helix has doors where he can stick out his feet to hold the bike up. If you put the rider's feet inside the body work, you'll either have to do that or make an outrigger setup that can be deployed at stoplights, etc.

Additionally, this bike doesn't seem to have a very low cg, and with all that battery mass up front and high, the steering may be very dicey. My experience is limited to bicycle frames, but you should look carefully at the rake and trail you really want before you mount the new Honda head tube. You could also see how much of the battery weight you can get *under* the lower frame tubes to lower the cg. I disagree that just because your cg is low, crosswinds won't affect you, but yours isn't going to be low anyway, so unwanted aero forces are likely to be substantial.

There is indeed a structural weakness problem with the upper shock unit pickup creating a bending force likely to crack the seat back bottom welds, or otherwise cause trouble, as John818 pointed out. This area is going to be difficult to triangulate, or even gusset, but you need something there unless you go to a monoshock swing arm that loads the frame directly and not the seat back.

Lastly, and I'm no Joan Claybrook, but I have to say this one kind of scares me. It looks like it will have squirrely handling. More than that, if you lay it down, a major leg crush injury is going to be all-too-easy to sustain. I would think about adding some tube structure outboard of the lower frame rail so that the rider's legs won't be between the frame and the ground if it were to topple. I know, we don't build them to crash them, but as it is, a simple driveway tipover could lead to a big-time injury. I'm also a little spooked about the rider's relationship and proximity to the vertical battery framing, (what is going to bang into what?) but a seat belt and helmet would likely solve that. Don't get me wrong, I love this thing, but the older I get the more conservatively I look at safety and failure modes...

Having said all that, man, its cool. I'm anxious to see it running with Mark's motor, because I think this bike will be a little over his recommended 400lb weight rating. Since I'm bouncing around the same weight with my trike, your experience will really help me with getting operational data points at this weight. This bike will be a great test bed for the EnerTrac hub motor. Great job so far!

TomA


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## todayican (Jul 31, 2008)

Great to hear from you TomA!

You've made some excellent points. The bike has gone through some "refinements" all towards moving the project forward safely.

1) The battery box is 1 box running the length of the bottom of the bike, so all batteries (45 cells of thundersky 60ah units or 300 plus headways) will be below the rider. Seat bottom will be 15" from roadway.

2) We "eyeballed" the rake to be a few degrees out from the sportbike (a ninja) we have here in the garage, and a few degrees in from the cruiser.

3) the design calls for "partially faired" riders legs. (In other words "cutouts" for feet and legs so they can be removed freely for propping the bike up at a stop.

4) lower gussets going in this week for the seat mount.

5) were going to add a length of 1.5 square tubing to the bike in the area of the riders knee (under) to form a kind of "slider" for laydown accidents to act as a leg protector (great catch Tom)

Hows that trike of yours coming?


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## kek_63 (Apr 20, 2008)

todayican said:


> 2) We "eyeballed" the rake to be a few degrees out from the sportbike (a ninja) we have here in the garage, and a few degrees in from the cruiser.


Do yourself a favour and look at some of the "rake and trail" calculators that the chopper builders use. Too much trail and you need arms like Hulk Hogan to maintain a straight course at low speeds. Too little trail and you just built yourself a tank slapper at high speed. 

Google will find you a bunch - helped me a lot with the handling on my chopper.

Keith


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## TomA (Mar 26, 2009)

todayican said:


> 5) were going to add a length of 1.5 square tubing to the bike in the area of the riders knee (under) to form a kind of "slider" for laydown accidents to act as a leg protector


Great plan. Make sure it isn't just a stick of square tube coming out at right angles from the frame rail. That will not do well in shear (scrubbing along the ground.) What might work well to reinforce it is a wide triangular or trapezoidal shaped sheet of steel as a vertical "bottom" gusset, that runs along from the outer tip of each slider and ties both sliders to the lower frame. That would be really strong for not much more weight, and while I wouldn't want to slide 500 feet on it, it would not likely collapse in the typical lay down almost every bike sees once or twice in its life. BTW, round tube is actually stronger in this application, if you have it.

The Moonray is gradually coming together as a final, buildable design. I've ditched the "full composite monocoque" chassis concept for a hybrid body-and-subframes setup of front and rear CrMo stub frames, with the body that connects them being a stressed-skin kevlar/epoxy envelope incorporating the pilot capsule and battery boxes. Sounds more complex than it is, but I'm happy with it and it seems to be cool. Weight estimates to follow the model, wherein all the really tricky packaging problems are to be solved.

Tiny parts are finally being made. Here's a pic of the first part I made in 1:3 scale. Its an upper suspension a-arm, in styrene, steel eyebolts and epoxy, that will be 3/4" 4130 CrMo with heim joints on the Moonray. The popsicle stick is for scale. Yes, this means my dream of using standard quad components is over, but I'm happier with parts that are exactly what I need anyway. I have the anthropometric (1:3 scale Tom) pilot model built, and the batteries and wheels for the model almost done, but its time-consuming having to make everything from scratch. I have three sets of batteries mocked up in 80Ah, 60Ah and 40Ah, which will help to figure out what configuration works best. So much more to do! Swing Arm, Spindles, Shocks, Brakes, Subframe, Body Shell, Canopy, Aarrrgh... 

The good news is, if the trike is right in 1:3 scale styrene, corplast, duct tape and home center hardware, (cheap stuff) I shouldn't have a huge amount of trial-and-error work in CrMo, Kevlar, honeycomb and Lexan. (The opposite of cheap stuff...) I've already made some mistakes acquiring parts, and I'm now committed to completing the design model before I go any further on the actual Moonray. The full-scale build will go faster this way, too, once I know what I'm building... 

TomA


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## Vanquizor (Nov 17, 2009)

Spent some time looking at your layout and thinking about the aero and stability. I suggest you look at modifying the nose- I overlayed a suggestion on your drawing that gives an improved center of pressure ( moved rearward ~8 inches and lowered ~4) I put the old center of pressure on it in orange, the new one in pink and offered a suggesed nose using pink for the body outline and yellow for a windscreen (or see-through body bits. The center of pressure is still pretty high (roughly at the top of the tires) but not out of line with what some production bikes have. It could be further improved (and aero benifit added) by putting a boat tail and fin behind the rear tire below the existing tail.


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## TomA (Mar 26, 2009)

todayican said:


> (45 cells of thundersky 60ah units or 300 plus headways) will be below the rider. Seat bottom will be 15" from roadway.


Hmm...

That's 5.5lbs x 45 or almost 250lbs of Thunderskys, more than that with intra-pack wiring and BMS. That's a lot.

300 Headways would be 200+ pounds for cells without any mounting hardware, wiring or BMS. Also a lot. 

Are you sure either pack will really fit on the bike, and do you need that much juice? 

I am thinking 48 x 40Ah or 30 x 60Ah for the Moonray. Either pack would be around 165lbs. If the 'ray stays at 400lbs, with a small frontal area and .25 or lower Cd, that'll be plenty of power for me. I figure it as a little more than 1/2 gallon of gasoline equivalent (in either pack) to 80% DOD. The configuration decision will come down to speed, range and packaging preferences. If the Moonray were ICE powered, it would probably go 30-40 miles on that much gas. Not fantastic, but it keeps me near 400lbs. 

If you really carry 250lbs of batteries, your bike is going to be 500 lbs, maybe closer to 600. Mark's motor will disappoint you at that curb weight. Start calculating your mass now. Are you going to carry a charger and cord? 12V battery? Comfy seat? Pounds add up fast. I've been at this featherweight game for 6 months now, and there are no easy answers...

TomA


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## TomA (Mar 26, 2009)

Vanquizor said:


> I put the old center of pressure on it in orange, the new one in pink and offered a suggesed nose using pink for the body outline and yellow for a windscreen (or see-through body bits.)


Do you mean Center of Pressure, or Center of Area?

With a bike like this of basically tapered tubular planform, they may be very similarly located, but they are not precisely the same thing, are they?

On my reverse trike I'm pretty sure these points will be in different locations, as the cross-sectional area isn't symmetrical from front to back, but is greatest just aft of the front two wheels and diminishes rapidly thereafter, where the center of (lateral) area will be significantly farther aft than that point. I'm wondering out loud here, because I'm no aerodynamicist...

For this bike, I wonder if and how the Center of Pressure would be impacted by turbulence from the wheels, the rider's exposed legs and open cockpit. Does any of that matter?

TomA


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## Vanquizor (Nov 17, 2009)

I was talking about center of pressure, and made an educated guess based on the relatively symetrical original design. My guess could be much farther off for the revised design given the increased complexity, but the idea that it is more stable because it will have moved lower and rearward is what I am trying to communicate. If a design is symetrical the center of area and center of pressure will be the same, if not... leave room in your design for adjustability. 

***EDIT*** I was envisioning a closed streamliner... with open torso and legs leave more room for adjustability. Also I was assuming a static situation- once you add in some forward motion the genter of pressure and center of area can be vastly different.


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## TomA (Mar 26, 2009)

When in doubt, check with a master.

Craig Vetter posted an astonishingly simple method for determining the center of area, and a less astounding, but equally simple way to locate the plane of the cg (but not its height) a couple of months or so ago:

http://www.craigvetter.com/pages/470MPG/Last Vetter Fairing P28.html

Thanks, Craig, youda man...


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## _GonZo_ (Mar 23, 2009)

This may interest you:

http://www.go-one.de/index.html
http://www.aerorider.com/nl/aerorider.html


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## TomA (Mar 26, 2009)

_GonZo_ said:


> This may interest you:
> 
> http://www.go-one.de/index.html
> http://www.aerorider.com/nl/aerorider.html


No thanks, I don't want a velomobile... 

These are laughably expensive ($1800 for headlights and turn signals?) and in a completely different class of weight, performance, safety, registration and practicality than the Purpose built Recumbent Electric Motorcycle that is the subject of this Thread (or my reverse trike,) but velomobiles are cool and they are indeed interesting to look at.

What todayican and I have in common is the hub motor we intend to use- it is 10kW continuous and 30kW peak. That's many times more powerful than a velomobile motor, and it needs at least a road-licensed motorcycle to carry it and the batteries it uses. At 50+ lbs, the motor unit alone weighs almost as much as a velomobile. Two of these motors could power a very small car. 

Think of it this way- the hub motor, from Mark at EnerTrac, really determines the class of vehicle one builds around it- ideally, about 300lbs-400lbs of curb weight per unit. That's the playing field here.

Velomobiles are way cool, but off-topic...

TomA


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## sunworksco (Sep 8, 2008)

Just a thought....
A reverse-trike with batteries and motor up front with the motor driving the front wheels with a limited-slip-diff will have better handling.The center of gravity should be slightly behind the front wheel ,regardless of reverse-trike or two-wheeled recumbent bike.You will otherwise get rear wheel slip in turns.You can also build the chassis with the Lotus technique of aluminum/epoxy/Ejot rivet screw construction.Zero welding and stronger/lighter than steel.All metal www.Alulight.com aluminum foam panels can also be bonded to a monocoqe fiberglass body for an even lighter bike.


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## ev_nred (Sep 23, 2009)

sunworksco said:


> Just a thought....
> A reverse-trike with batteries and motor up front with the motor driving the front wheels with a limited-slip-diff will have better handling.The center of gravity should be slightly behind the front wheel ,regardless of reverse-trike or two-wheeled recumbent bike.You will otherwise get rear wheel slip in turns.You can also build the chassis with the Lotus technique of aluminum/epoxy/Ejot rivet screw construction.Zero welding and stronger/lighter than steel.All metal www.Alulight.com aluminum foam panels can also be bonded to a monocoqe fiberglass body for an even lighter bike.


how much would it cost with a top speed of 50 kmh and a range of 100km 16k mabey thanks this reminds me of the go-one (http://www.go-one.us/) migth be a good winter for you good luck


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## todayican (Jul 31, 2008)

Progress!

Due to me getting a recumbent trike (bicycle) and moving our home 3 miles, slow progress.

But...

Per some excellent advice from Tom A we added some support to the lower rear frame and added some "leg protection" in the process.

Should have shocks mounted and be ready to deliver to the "Body guy" next week


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## sunworksco (Sep 8, 2008)

ev_nred said:


> how much would it cost with a top speed of 50 kmh and a range of 100km 16k mabey thanks this reminds me of the go-one (http://www.go-one.us/) migth be a good winter for you good luck


My design is nothing like the Go-One.
The front-drive wheels and motor are more forward with the batteries behind the front axle.This gives a perfect CG.The motor to Honda limited-slip diff is belt-drive
The chassis is built similar to the Lotus chassis.
The trike can do what you are asking , if it is below 650lbs. and has a 45hp ac motor with a 96volt lithium iron phosphate battery pack.I would recommend using motorcycle parts,preferably a Ducati 1098.I have bought a wrecked one for mine.
There are some very good aluminum race-car front wish-bone suspension components in the UK and Australia for the reverse-trike chassis.You can even use late model front wheel-drive Porsche 996 strut suspension and drive axles.these are inexpensive parts at the breakers yard.You can even eliminate the shock tower and use a custom upper wish-bone,then add a Ducati 1098 rear shock.


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## TomA (Mar 26, 2009)

sunworksco said:


> There are some very good aluminum race-car front wish-bone suspension components in the UK and Australia for the reverse-trike chassis.You can even use late model front wheel-drive Porsche 996 strut suspension and drive axles.these are inexpensive parts at the breakers yard.You can even eliminate the shock tower and use a custom upper wish-bone,then add a Ducati 1098 rear shock.


Please tell be about these aluminum racing arms. 

The Porsche components are almost certainly too heavy for my vehicle, and "inexpensive parts" is a matter of perspective, I suppose. As parts go, the Ducati rear shocks may not be very pricey, but AWD Porsche parts will never be cheap in the US.

Anyway, what aluminum arms are you referring to?

Thanks,

TomA


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## _GonZo_ (Mar 23, 2009)

I think that new stock BMWs are mounting aluminium ssupension arms at the moment.


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## TomA (Mar 26, 2009)

The Corvette has been using them for many years. Same with some Audi, Ferrari, and surely others in the high-end class. The OEM arms are all forged, which would be a huge undertaking for an aftermarket supplier of something as low volume as, say, kit car or hot rod chassis parts.

Steeda makes aftermarket aluminum arms, for Mustang suspensions, but only on the rear. 

Jerry Kugel has made arms out of cast stainless steel for his hot rod suspension kits for many years. It isn't so much that they are lighter, but that they are much dressier for a fenderless hot rod. That's usually the case with stainless and billet parts of any kind...

Anything else out there?


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## ev_nred (Sep 23, 2009)

sunworksco said:


> My design is nothing like the Go-One.
> The front-drive wheels and motor are more forward with the batteries behind the front axle.This gives a perfect CG.The motor to Honda limited-slip diff is belt-drive
> The chassis is built similar to the Lotus chassis.
> The trike can do what you are asking , if it is below 650lbs. and has a 45hp ac motor with a 96volt lithium iron phosphate battery pack.I would recommend using motorcycle parts,preferably a Ducati 1098.I have bought a wrecked one for mine.
> There are some very good aluminum race-car front wish-bone suspension components in the UK and Australia for the reverse-trike chassis.You can even use late model front wheel-drive Porsche 996 strut suspension and drive axles.these are inexpensive parts at the breakers yard.You can even eliminate the shock tower and use a custom upper wish-bone,then add a Ducati 1098 rear shock.


srroy for not posting erailer but I have been busy. thanks so much for all the info!! srroy but I am not going to build it. I was just wondering I didnt thinke you would pot so much time in this post. however I migth build it in a few yers (when I get my drivers lisnce, money and skills) but thanks so much for all the info and srroy for makeing you waste your time!


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## gor (Nov 25, 2009)

TomA said:


> ...
> What todayican and I have in common is the hub motor we intend to use- it is 10kW continuous and 30kW peak. That's many times more powerful than a velomobile motor, and it needs at least a road-licensed motorcycle to carry it and the batteries it uses. At 50+ lbs, the motor unit alone weighs almost as much as a velomobile. Two of these motors could power a very small car.
> 
> Think of it this way- the hub motor, from Mark at EnerTrac, really determines the class of vehicle one builds around it- ideally, about 300lbs-400lbs of curb weight per unit. That's the playing field here.
> ...


Tom, could you comment more on motor 10 kw const. 30 kw peak? 

about EnerTrac manufacturer only says:

"Power output: 10KW continuous @ 25c ambient temperature
Typical Voltage needed:
72 volts for 30 MPH with 18 X 3.5 tire
96 volts for 45 plus MPH with 18 X 3.5 tire
Typical current demand:
At 72 volts and 30 MPH < 33 amps
At 96 volts and 45 MPH < 50 amps"
http://www.doingitall.net/EnerTrac/product.php#b?
thank you


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## Acemon (Dec 28, 2009)

I'm new to this forum, but not new to recumbent motorcycles. I'm building one using a Honda VF700 sportbike with an extremely modified frame and my own design front suspension. You can find my extensive website at www.ProjectVF.com Too many well-meaning recumbent builders gave me advice on steering and handling, yet their designs were based on "what felt right," so I built a relatively cheap & crude mule to test various combinations of rake and trail. If you're interested in seeing the results, I have a lot of data published within my site. 

I did a lot of research in the past regarding electric vehicles, but it was the weight and size of the batteries, in relation to their output and range, that kept me from pursuing it further. There has been a fair amount of evolution in the technology since then, but I'm not quite ready to jump in and give it a try. I'm certainly going to watch the progress of your recumbent and see how it turns out.

I also visited your website and looked through the construction of your three-wheeler. I like how it looks and I bet it'll be a blast to drive. You definately have a lot of projects on your plate.

Best of luck!

-Ace-


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## TomA (Mar 26, 2009)

gor said:


> Tom, could you comment more on motor 10 kw const. 30 kw peak?
> 
> thank you


The spec on the EnerTrac website is a little lower than what Mark actually thinks the motor can do. That's smart, he is being conservative with his performance claims. You can follow the whole evolution of the motor, and many comments Mark has made about it, here:

http://endless-sphere.com/forums/viewtopic.php?f=10&t=7718

In fact, from the hints Mark is dropping these days, the next generation motor may be significantly uprated. Its really impressive to see someone do their development and testing in public like this; answering direct questions and posting actual test data. Mark's motor is good, and if development continues at this pace it will get even better shortly.

I don't have any special information about this motor, but I think its fair to say that its actual performance envelope is somewhat unknown, especially since it is still in development and hasn't had many road or customer miles. The Purpose built Recumbent Electric Motorcycle that is the subject of this thread is in fact designed to explore the contours of that performance envelope. That's what I'm most interested to see...

TomA


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## TomA (Mar 26, 2009)

Acemon said:


> I did a lot of research in the past regarding electric vehicles, but it was the weight and size of the batteries, in relation to their output and range, that kept me from pursuing it further. There has been a fair amount of evolution in the technology since then, but I'm not quite ready to jump in and give it a try. I'm certainly going to watch the progress of your recumbent and see how it turns out.
> 
> -Ace-


Ace, your bike is sensational. I really like your methods, too, especially the models and mock-ups. Nice way to proceed. You've really done the homework on bump steer and the double wishbone suspension is great! 

This is actually a great time for you to jump back into electric. The prismatic (ThunderSky, Sky Energy) LiFePO4 batteries are here and completely change the game for electric vehicles, particularly lighter weight ones like motorcycles.

TomA


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## Evilsizer (Jan 25, 2010)

any updates?


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## todayican (Jul 31, 2008)

Havent worked on this one in a while. anyone want a hell of a deal on the rolling frame and move it forward?


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## zeroemission (Sep 14, 2010)

kind of late in the game, but the sketch looks really top heavy to me. i picture mounting a pair of batteries behind the driver on either side of the rear wheel as low as possible without altering the profile to be more stable and offer better front to back weight distribution. it might not be as much of a problem with a lower recumbent design, but i've learned even lightweight bookshelf speakers in saddlebags make a mountain bike want to tip over like crazy the second you stop riding. once you're rolling, they aren't an issue unless you try to change direction quickly, but after that experience, i try to lower the center of gravity as much as possible on 2 wheels.

if it turns out to be a problem with your design, retractable landing gear (training wheels) could help and i've seen those used on 2 wheel designs before.

more than anything though, i'd be terrified of becoming invisible to motorists in such a low vehicle on the highway. have you ever thought about reflective paint?


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