# Tilting tadpole trike scratch build



## Gene (Apr 8, 2009)

Hi,

Don't worry about what other people think of your ideas, if you feel like building something innovative and you have the means to do so go for it.
There's someone on this forum who is doing a similar build.
http://www.diyelectriccar.com/forums/showthread.php/three-wheeler-26208.html
Maybe you can exchange idea's and help each other.
Good luck with your build.


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## mattW (Sep 14, 2007)

Welcome to the forums. Sounds like a great project. I have dreams of a tadpole scratch build trike in my post-lottery future also. Looking forward to seeing photos and CAD screenshots. I will be living vicariously through you.


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## davidru (Apr 12, 2009)

I'm a big fan of leaning trikes, even started on a design for a leaning velomobile (goofy low res cad doodles here http://www.dave.com/trike.htm). Maintaining correct steering geometry (Ackerman) at all points of lean and steering angle was a bit of a geometric puzzle, but I got it pretty close, with no more than a half degree of error from 0-45 degree lean and +/- 20 degree steering.

Are you dead set on fly by wire leaning? My impression is that a leaner can work like a normal single track vehicle, i.e. with countersteering. Downside is that stopping at a light can be a challenge, as they tend to fall over without help, just like a motorcycle or bicycle. Most "free leaners" use some kind of lean locking mechanism to hold them upright at low speeds. Making a U turn on a 30% grade could be interesting though 

Although the controversy about stability of tadpole vs delta is largely moot with leaners, I prefer the looks of the 'tad, and the simplicity of a single driven rear wheel. The exposed front wheels do add to aero drag though. I can't help but think the leaning trike is a better solution to stability than something like the non-leaning Aptera with it's semi truck width. Maybe the Aptera is a safer (as in less product liability exposure) for the masses though.


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## Hordur (Jun 9, 2009)

Ive been having a design competition on a 3d forum and have found a pretty decent design... 

So the outer and inner design is pretty much complete (with some minor modifications)

The frame will be simple, with most of it will be visual (the roll bar behind the seat, the dual tube sides with crossmembers and so on.
Some interior framework needs to be designed aswell as fit the leaning mechanism into the front end.

The body will be moulded in fibreglass and add structural strenght to the vehicle. A core-material will be used (similar to surfboards) and strenghtened by glass and carbon fibre tubes (fibre socks) that will be sandwitched into the composite.


Im not sure of the weight anymore, but im guessing somewhat under 200kg inkluding a 15kw drivetrain and 4x 12V batteries (as placeholders for LiIon/LiPo batteries)


I have a question.. 
Is it possible to connect a battery pack in such way that i can easily while driving shift between power configs?
Shifting battery config could be like shifting gears 

Im thinking 1S4P (1 in series, single, 4 in paralell) or 2S2P for tourqe on low revs, and 4S1P for highspeed with low range.

i also been concidering if i can connect a separate 1s4p 12v battery connector on the existing batteries regardless of their propulsion configuration.
Meaning, can i connect the same battery pack with both 12v 4paralell and 48v outputs simultaniously?


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## rillip3 (Jun 19, 2009)

Really nice looking!

I love the idea of three wheels, and really want one, but the state laws here are goofy. Anything that has less than four points of contact with the road is concisdered a bicycle for legal purposes, which means having to get a motorcycle liscence. Getting the year long permit is easy, it's like a 10 question test, but getting the full liscence is signficantly more difficult and expensive than getting a regular liscence.


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## Guest (Jun 27, 2009)

rillip3 said:


> but getting the full liscence is signficantly more difficult and expensive than getting a regular liscence.


But well worth the time and effort. Remember if you don't want to use the trike for the test you can always borrow a regular bike, then take the test. 

Pete


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## rillip3 (Jun 19, 2009)

gottdi said:


> But well worth the time and effort. Remember if you don't want to use the trike for the test you can always borrow a regular bike, then take the test.
> 
> Pete


See, there in lies the rub. You have two options to get your liscence: take a class at the local college. Easy, but they always offer it as a night class, and I work nights.

The second option is to just go take the test. The last part is to take a cone test, and unless you're an experienced rider, you will not pass. Which is somewhat counter intuitive. In order to be allowed to drive a motorcycle, you have to be an expert at driving a motorcycle, which you can't drive legally...? It's like they didn't really think too much about that.

Essentially, the test looks something like this
___
( )
\ /
| 
|

There are cones, placed no more than four feet apart, and you have to slalom through them. At 5mph. If you touch the ground, you fail. If you go over 5 mph, you fail. If you miss a turn, nick a cone, or go outside the lane markings, you fail. And unlike the car liscence, where you take the test, and if you pass you pay for your liscence, you have to pay to take the test.

I thought about it hard before starting my EV conversion, and deicded that learning to ride and take the test would be more stressful than it was worth. Though if I got a chance to snag this or an Optera...


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## Guest (Jun 27, 2009)

> See, there in lies the rub. You have two options to get your liscence: take a class at the local college. Easy, but they always offer it as a night class, and I work nights.


Well that is a bummer but I am sure you can find a private company that will fit your time constraints. There is always a way around the issue and getting your motor cycle license is well worth the time, money and effort. 

Pete


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## rillip3 (Jun 19, 2009)

gottdi said:


> Well that is a bummer but I am sure you can find a private company that will fit your time constraints. There is always a way around the issue and getting your motor cycle license is well worth the time, money and effort.
> 
> Pete


Maybe when I'm done with my ev conversion I'll see about it. I think I'll try for some sort of three wheeled vehicle for my next conversion.


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## toddshotrods (Feb 10, 2009)

Ohio has seperate two and three wheel motorcycle licenses. I have had my motorcycle endorsement for a couple decades now. I always wanted to get my trike endorsement but never had access to a trike to do it. Maybe that's a good excuse to build an EV trike! 

Our riding test was similar (with cones, etc) but we get a learner's permit after passing the written test. No passengers, no riding after dark, no freeways, etc., while riding on the learner's permit. I had been riding for a couple years before I actually took the riding test, and had heard all the horror stories of people hitting cones, wrecking their bikes, failing the test...

I was on a 77 Kawasaki KZ1000 and breezed through the test like it was nothing. I got five points off for showing off and doing a full panic stop instead of placing my front wheel on the line at the end of the test. Yes, I got penalized for being able to haul my bike down too fast! 

The point is, if you can really handle your bike you can pass those tests. They are designed to weed out the people who are likely to kill themselves due to not being able to handle the bike.

Set up some cones (plastic bottles) in a parking lot and practice until you're confident.


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## Russ_VC (Mar 5, 2009)

I California, the motorcycle safety foundation offered a CHP (Ca Highway Patrol) approved course takes a full weekend, but gets you out of the DMV driving test and an insurance discount for having taken a safety course.

Love the trike design you came up with. In leaning mechanisms, I like the one off the Brudeli 625L. Simple, easy to understand from the website pics.


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## Cdog (Oct 18, 2010)

Great Idea!!! Already prototyped by someone and being shopped to investors. See it at

http://www.revolutionmotors.biz/revolution/


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