bzhwindtalker's roadster

bzhwindtalker

bzhwindtalker

100 kW
Joined
Dec 1, 2008
Messages
1,807
Location
Lyon, France
hello all,
My hardtail build went well, but is not of mutch use exept for recreational fun, low range, I can't pedal as fast as the motor (44-18 single speed), and not weather-proof. So I started drawing and gathering info for a new build, a tadpole velomobile with an open cokpit.
I was posityvely influenced by the builds on this forum, great stuff.

So my project is to build an eficient alternative to a car, on distances up to 30km (60km two way).
3 wheels for stability, 20" front and 26" rear, maybe a moped wheel.
tadpole configuration, way more stylish!
Great or at least ok aero.
Rear wheel drive, using a car alternator for variable field and infinite motor gearing. (but a watercooled colossus motor would be great!)
sensorless 12 or 18 mosfet bmsbattery controller.
i'm not sure what cells I should use, but from my low power requirements, 20ah TS cells would do the trick and would be cheap.
48 volts, to start with.

Here my firsts drawings,
View attachment trike1.0_3vues 001.jpg

View attachment trike1.2_2vues 001.jpg

openkab.JPG

ducati red.JPG

started the actual build a week ago, but I forgot my phone with build pictures on it at the workshop!

I'ts going good so far, I use 17.2mm hydro tube, bent with a simple but trusty hydro bender.

The bottom tubes, the front boom, and the seat tubes are done, and thack welded in place.
I am now gathering info on steering angles and direction set-ups.

sorry for my spelling!
 
WooT another custom build best of luck looks sick so far *subscribed*

KiM
 
Here a little gnupaint job of what the final structure will look like.
trike side.jpg
I may work a bit less on it for the two or so months to come, as I will pass my exams, and I have an electric winch that need to be ready for this summer, wakeboarding on a boat is just sooo expensive!.
 
Interesting design!
It looks a bit narrow around the shoulders.
The tricky part of a trike is the steering. I built my 1st trike 20 years ago and the front tires were blank after 500km because I had a lot of friction while steering. Maybe you can find something about 'Ackerman(n?)' steering geometry.
It was also very difficult to drive straight while braking. I had two indipendent front brakes...

Good luck with your winch ( and your exam ) :)
Olaf
 
hum yes It's a bit narrow on the shoulders... but I'm short, so it should be OK :D watching the mock up, i feel the front end a bit too big, not really aero :? but I just need so much space to pedal...maybe I could reduce that using 140mm or smaller cranks?
Also, I was wandering where to put handbars... the only open space I have left inside is under my legs, and it would be simple and comfortable with a pivot on the end of the ''v'' of my front wheels support. But I think higher bars will bring a better driving experience... decisions...
 
Too bad, I have no pictures from my trike...
I had a custom steering that rested on my stomach while driving but could be tilted forward to climb on and off the bike.
Almost like a top steering recumbent but with an additional knee.
The reason why I built this trike was to show a proof of concept of my linear_constant_torque_pedal system I 'invented'
Unfortunatelly study and job never left enough time to built the linear pedal system. ( read: I was driving the trike with a common pedal system the whole time ;) )
It would've been a great reduction of pedal area and your front cover could be a lot smaller.

Today I don't have access to the required machines to build the linear drive and with my 1.5kW e-drive I actually don't need the extra torque it would give.
-Olaf
 
bzhwindtalker said:
do you mean some sort of stepper pedal system? I saw a concept somewhere...
Click to expand...

A stepper would take much more room and doesn't have the constant torque feature like my version:

You'd need two linear moving pedals and two freewheeled sprockets/pulleys sitting on one shaft to turn the final drive sprocket. Both pedals are mainly independent, but for drivers comfort they can be coupled to mimic an back/forth oscillating movement. ( I'm struggling for words here :oops: )

Could someone point me to a free 3D-CAD program to make some illustrations?
Olaf
 
I think i see how this could work, the interest would be to have the foots translating on the same horisontal axis? like that you could have a very sharp front end, needing at max the heigth from foot to knee. Definitey appealing! but the mecanical part seems not so easy to set-up and possibely heavyer?


sorry for my writing, no spellcheck on my nokie yet ;)
 
some progress today! here we say "avoir le compas dans l'oeuil" when yon can draw, cut and weld whithout marks or square tool to draw on your material. but today it was not really the case for me! I welded two tubes on the rear to help the strench of the rear drops out, but one is at least 1cm out! I also welded a tube to help with lateral flex on the bottom of the chassis, that will also be used as motor mount. This one was out by maybe 5deg. The chassis looks good but starts to be heavy.... UNDER 45kg would be ok for a first try, but I dont know if I will be able to achieve that goal!Nakedchassis2.jpg
Piloteview.jpg
 
Actually it's not neccesary to build the whole frame from steel. Everything further in front than the pedals can be made of fiberglass.
I'm curious how you want to enter the cabin?

The Thijs rowing bike is a nice idea. ( The tandem is SICK ) ::put two puking smilies here::
The drawback is the long period of non power, when the driver has to fold his legs for the next row. My idea would have a counter-oscillating move with no torque interuption to talk about.
Miles: The CAD proggy wouldn't work for me, I don't have the right windows version(s). :cry:

-Olaf
 
yeah fiberglass over samba would have been so cool, but the weather here would not have allowed fast progress... resin need low humidity and high temp. If i redo it, I'll probably go with thin alloy tubing. But steel is easy to work with, It will be ok for a first try. Getting in/out will be a bit of a trick, on leg over the top bar, foot on the front wheel support, other leg on it, then slide in. it's a bit long but easy. Do you think stepper/ pusher setup is worth the extra mechanical work involved compared to 140mm crank arms?
 
bzhwindtalker said:
...
Getting in/out will be a bit of a trick, on leg over the top bar, foot on the front wheel support, other leg on it, then slide in. it's a bit long but easy. Do you think stepper/ pusher setup is worth the extra mechanical work involved compared to 140mm crank arms?
Click to expand...

I wanna see a video of that acrobatics LOL :D

The linear drive is only worth it when you try to build a low drag hull. There are competitions to win and worldrecords to break with such an advantage. ( bit bragging here ;) )
But for your first DIY trike it's a bit overkill. It's not that complicated to build but the whole design should be wrapped around it.
-Olaf
 
yeah linear drive are something to look into!
got some worck done on the trike, started the drops-out, I made them beefy so they can hold a hub motor ''if needed'' :wink:
I also got the crank in place. Now I will let somebody play with the tig to finish the welding. I work on this build in an associative workshop, created by naval construction retired guys, they can do pretty much anything with steel :) they work on old cars, old mopeds, go-carts, they repair cars for friends, It's cool, they are really happy to help anybody with their projects, and it's 10euro a year for students.
drop1.jpg
View attachment 3
trikecrank.jpg
sidetrikec.jpg
trikeup.jpg
 
suspention... to do 60+kph confortabily, I think I will need at least front suspention, 3-5cm travel on each wheel. I will use moped tyres, but do you think it will be ok on a 45kg frame at high speed?
 
Looks great so far man, very nice lines!! I like your original drawings and hope it turns out similar. I also think moped and go carr parts are perfect for this application. It's a bit archaeic, but have you thought of springs for suspension like the cheap go carts use? I wish I could post a pic from my phone so you know what I'm talking about, but it's like a spring around the steering pivot or pin that allows the axle assembly to move up and down.
 
Do you mean a sort of torsion bar ? old French cars here ( Citroen 2cv) use this sort of suspension in the rear. I can use a spring around the front lateral tube, and put a 10cm lever in the front of it. This would be simple enough to be doable, but it would change the steering angle as the suspension acts. Suspension would be really
cool to have. IF i can find a company to support me on battery, I may try to make a big loop in Europe this summer, 200km/day should be doable with 1kwh of lithium and 50w solar panel. I was planning a 3week road trip in china this summer, but with the loss of euro, it was like 800euro just to go there !
 
Some cool info! thanks to Justin ebike.ca, I will use a cycle analyst!
http://ebike.ca/
A big thank to them!
I also made my decision of use 14' dirt bike wheels and brakes, two front wheels were 40euro delivered! Heavy, but healthy!
The rims is are a bit smaller than 20' bicycle wheels, but the fatter tire will compensate. They use 12mm axles. Weight objective updated also, it will be ok if I stay under 60 kg with battery.
 
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