RETROADSTER, a quad tandem

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Hello all.
A few years ago I had found pics of the so called"Velocar", while searching online for bike related stuff.
These vehicles were build by the french manufacturer Charles Mochet from the late 20s until the middle of the 50s.
They were basically bikes, but build like a car in sociable configuration with four wheels, partiallly whith suspended front axle.
VelocarTypeF.jpg

mochet-velocar-2.jpg

45-Mochet-Velocar-DV-08_HHC_0004.jpg

Up to 5 gears for both driver and stoker where available in the final models.
Mochet used very thin plywood (1-2mm)for the fairing, with a layer of paint and fabric on the outside to make it weather resistant.

Very few of these vehicles survived, no possibility for me to buy such an ingenious vehicle.
One Velocar (freshly restored) was sold last year on a well known online platform, for a very reasonable price of 2500€.
The Microcarmuseum auctioned a few this year for prices...wow...five, six times higher.

So my idea was, to build my own Mochet-inspired sociable.
DSC00530.JPG

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I want to use most modern and easy available bike parts and least specially constructed ones.
Since May 2012 it's driveable, used as family tandem with room for 2-3 childs in the rear box.
DSCF0181.jpg

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DSC00517.JPG

DSCF0198.jpg

As I planned the build I was a little bit too optimistic about the weight calculation of the "Retroadster".
I had estimated around 100 pounds with the fairing, but ended up with over 120 pound without the shell.
So weight saving is recently my biggest issue.
This results in a new frame build from 4mm birch plywood.
It's in fact lighter than the steel frame AND doubleacts as part of the shell (i.e. the entire bottom)
DSCF0636s25.jpg

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The last pics are showing the recent construction stage.
Next steps are the assembling of the axles, steering system, seats, backseat and then finally the fairing.

I'm still brainstorming about the final look.
More aggressive like the model, eventually shark teeths made from alum in a beast mouth shaped fake grille,
hidden head lights like this car
Peugeot_402_Custom.jpg

a little bit H.R.Giger and so on.
I'm glad to read suggestions from you, so feel free for comments and critics.

So long
Kai
 
Last edited:
Your going to make me want to do another velocar.
Post your up-dates--I like seeing them.
I'm interested in weight saving too.
 
Here are some pics of the beginning of construction.
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The rear wheels are offset outwards from the chain line.
This provides more useable space between the rear wheels (70cm/28inches breadth for the backseat), increases the cornering ability of the tandem because of the wider track (90cm/36inches), but makes chain offset axles necessary.
The second picture shows these axles (under the seat), which I want to retain on the wooden frame.
They are made from steel front hubs (lengthened on the stokers side) with welded on sprockets from disassembled rear hubs.
Here is a ratty sketch about the transmission:
karosse+Hinterbau+2.jpg

Both drivetrains are independend from each other, basically like two separate bikes.
That means, each driver can shift independently, can maintain his/her own cadence and stop pedalling while driving.
But uphill the power of both drivers is necessary, otherwise the busy driver will be very frustated about the lazy one.
But this is part of tandem driving.

Kai
 
First Silver Moon Velo for frameteam and now this beauty! Something tells me that we will see more of these on RRB.
I love the engineering that went into Retroroadster 1, but I am even more interested in the wooden version of Retroroadster 2.
Thanks for sharing! Please keep us updated on the progress.
Also, WELCOME to RRB!
 
@LTJ: It`s steers quickly, sometimes too quickly. These short middlestick i'm using is'nt that comfortable and not safe enough.
One hand steering is more difficult to handle.
Especially on bumpy roads the vibrations of the car shakes the pilot and that influences an one hand steering system more than I had expected.
The next steering version will be a normal handlebar.

@ outskirtcustoms: The "Poor"sche is well known here. It`s an austrian art project of Hannes Langeder, intended to "de-accelerate" the traffic by driving an Porsche-shaped vehicle with 3 miles/hour through the city.
After the Porsche he has build the "Fahrradi" (Fahrrad means bicycle :D )
http://www.youtube.com/watch?v=IeWCY7ihcj0

Kai
 
Way neat!!!! I've always thought pedal powered vehicles were really interesting. Have any of you guys heard of the Kinetic Grand Championship?? (If any of you are from my neck of the woods of course you have!) I helped design and engineer a few of them in high school, they're a whole lot of fun especially when you have a big group.

I know it defeats the purpose, but I want to build a quadricycle like this that's powered by a Briggs V-twin or something.... I guess sort of mini, four-wheeled version of a Morgan three-wheeler...
 
@ Kingfish & CCR: Thanx for your interest!

@ frameteam: Bicycle diffs are hard to find on the german market.
So thanks for the link.

I have preferred the solution with independent rear wheels.
It's not that impractical as some people may expect.

The single driver case:
In a normal car a diff works great, because there is no big movement of the center of gravity.
The car weights 1.5 to 2 tons and the driver on the seat (in most cases offcenter) 150-200 pounds.
The loads of the left and right wheel are nearly the same.
But on a light sociable the pilot weights more than the entire vehicle, in my case 120 pounds the car, my weight is 180 pounds, means 150% of the car.
Sitting on the left side, the left rear wheel is much more loaded than the right wheel.
Imagine, what happens, when you single-driving with an normal differential on uneven, bumpy roads.
The unloaded right wheel will loose grip very often.
Not so, when I drive only the loaded wheel on my side.
Furthermore, the drivetrain I have to move is much smaller, which results in less waste of human power.
Not to forget less weight because of the missing differential, diff axles and so on.

The two drivers case:
The car steers well, differences between the pilots and stokers power has very small influence in the steering, because of the small rear track (90cm/3ft/36inches)) and the long wheelbase (2,1m/7ft).

The old Mochets had a one piece rear axle without a diff.
They used mounted on freewheels on each side instead.
That means, while cornering, the inner wheel (to the corner) drives the car.

Kai
 
@Shorty:
Your bikes are wonderful.
In Germany such self build motor bicycles cannot be driven on public roads, it's illegal.
Only pedal assisted electric motors with maximum 250 watts/ (called Pedelec) are legal and licence/tax/insurance free.
So I'm green with envy about your possibilities.

Kai
 
Plycar said:
@Shorty:
Your bikes are wonderful.
In Germany such self build motor bicycles cannot be driven on public roads, it's illegal.
Only pedal assisted electric motors with maximum 250 watts/ (called Pedelec) are legal and licence/tax/insurance free.
So I'm green with envy about your possibilities.

Kai

Thanks man! They have a lot of room for improvement, but thats why I'm here LOL! Thats crazy you can't have motor bicycles there!! Technically anything that's on the street with any kind of power here has to get a safety inspection and you need a motorcycle/drivers license, but at least where I live the authorities don't really bother you as long as your wearing a helmet and being responsible.

What kind of hubs are you using on the front that are mounted on just one side? Are they like wheelchair hubs?
 
Such hubs are also used for recumbent tadpole trikes.
I used Sachs drums taken from an cheap wheelchair, but my next build will be fitted with Sturmey Archer drums.
They are way better and available as 90mm XL version instead of the normal 70mm size, although this will produce costs of 250€.
They provide both more braking power and better sideward stability of the wheels, because of the higher hub flanges, shorter spokes, different spoke angle etc.

Kai
 
ShortyLaVen said:
Way neat!!!! I've always thought pedal powered vehicles were really interesting. Have any of you guys heard of the Kinetic Grand Championship?? (If any of you are from my neck of the woods of course you have!) I helped design and engineer a few of them in high school, they're a whole lot of fun especially when you have a big group.

I know it defeats the purpose, but I want to build a quadricycle like this that's powered by a Briggs V-twin or something.... I guess sort of mini, four-wheeled version of a Morgan three-wheeler...
Shorty check out:http://cyclekarts.com/
 
Very cool reminds me of the pedal cars that were used in the 1976 movie Bugsy Malone with Scott baio and Jodie foster The movie was filmed in England using all child actors 20's gangster cars that were all hand built pedal cars and thompson sub machine guns(splurge guns) that shoot whipping cream instead of bullets. "The cars on Bugsy Malone were custom built by hand. In fact each one cost as much to make as a regular road going Mini. Pedal-driven, they could do a very respectable 10 m.p.h. These have been mothballed at Pinewood awaiting a deserving home" Taken from a fan page of the movie.Here is a link to the movie on youtube right at 48 minutes in begins a chase scene that shows the cars in a action
http://www.youtube.com/watch?v=49fKPUiEKfY
 

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