Recumbent quadcycle: Pondering on a new (longterm) project.

[bicyclebuilder]

For a while now, I've been pondering on a new project. I've got a recumbent bicycle (two wheeled, no fairings, top steering.) and I love the way it sits on the road and the fact that it goes faster than an ordinairy racebike. The seat is extremly confortable and you could ride all day, without any pain or sour places. But.. it's not my own creation. It's a Challeng Hurricane, made for speed so minimum bits and bobs to customise. Also, I'm the only one that rides it. My wife is a bit shorter and a bit hasitant about riding the recumbent. Our daughter (almost 3) can't be transported with this bike, unless I put the bicycle trailer behind it.
What I want is a ridable vehicle, suitable for two adults and 1 (or 2) child(ren). A 4-wheeler, two seater was my first choice. First I was thinking in the lines of a Ford Model-T (Laurel and Hardy car), but that seems to high and topheavy as a quadcycle. Now I've got the Model-A (happy day's, Ralph Malph's car) as a blueprint for the quad. I don't want it to be an exact copy of that car, just as a guideline for the design.
As for the technical part, I'm thinking about two recumbent seats with one steeringwheel or handlebar for the left hand rider. Both riders get their own set of gears, standard mountainbike derailleur. With both a set of gear levers. Disk brakes all around, operated by the left hand rider. The two rear sprockets are combined with a rod and drives the third chain all the way back to the rear wheels.
I know there are off the shelve kits to turn one rear wheel into a double, with a differential gear. Also there is a kit for changing one front wheel into a double, steerable.
By law, I'm allowed to make the bike 150cm wide, maximum. Other than that, I'm virtually limitless. Good frame, proper breaks, steering etcetera, but no actual legal limits. (unless I add an engine, that's when I have to have it checked by othorities.
I have to keep it lightweight but strong enough to hold the family safely. For now I'm thinking either a aluminium frame with lightweight body or a body that is self supportive. Wheels are probably going to be 24" 2" tires on spoked wheels. Part of me wants narrow tires for speed, but the other part wants wide, cool balloon tires.
I'm visualising everything with Google SketchUp, to see what it would look like. Here's the first draft of the vehicle. It's mainly just cut and paste from a couple of models.

For now, I'm just putting ideas together and try to virtually gather the components. For what I've learned from bicycle building is that you need the components globally figured into place, before you manufacture.
First obstackle to take is room. I've got a garage, but it's full of bikes and a workbench.

[Lady Chrystal]

You might like to get hold of a copy of the film Bugsy Malone. It featured pedal cars of a similar style that may inspire you.

It's also a great, fun film.

[bicyclebuilder]

Thank you, Lady Chrystal. I remember that one, with Jodie Foster wasn't it?
I just Googled and Youtubed the vehicles from Bugsy Malone. It does look a lot for what what I'm looking for. The biggest difference is that I want to do a recumbent position and more lightweight.
I've also found a couple of pictures of a Mochet Velocar.

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Being from the early 1900s, it shouldn't be considered "Steampunk" to the purists, but I think it could have been from the Victorian era. But tell me what isn't Steampunk about this:


One of the options I'm working on is the kid seats. I have seen model A Fords with a foldable seat in the trunk.

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If I use that option, I can't keep the back passengers dry in the rain.
I could go for the sedan convertable version:

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But for single person trips, I don't want to drag along all the extras, and go for a clean look.

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And for trips to the market or supermarket:

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I could go for a modular system where I can just connect any back I want for that trip.

[Rooster]

For further inspiration, there is also the Morgan Pedalcar.

http://www.morgan-motor.co.uk/mmc/carrange/pedalcar/pedalcar.html

[Lachlan_MacAuslander]

If you're not already familiar with Atomic Zombie (www.atomiczombie.com, check out their gallery. They mostly sell DIY plans for enthusiastic welders, but some of the mutations and alterations that show up in the quad gallery might spark some inspiration...

[Narsil]

In terms of body/chassis design then there are a few basic options.

1) separate body and ladder chassis: this is the traditional way of constructing a car and is still used to a degree in commercial vehicles. The wheels/suspension, engine and transmission are supported by a flat structural chassis, typically two fairly heavy section structural beams (usually box-section steel)which run along the length of the vehicle floor parallel to each other, joined by transverse beams. Very much like a ladder.

The main advantages of this construction are that it is versatile, you can bolt on pretty much any body shape you want, and it is very simple to construct. The beams can simply be cut to size, laid out of a flat floor and welded or bolted together.

The main disadvantage is that it tends to be heavy, the body contributes virtually nothing to the structural stiffness of the vehicle and it tends to have poor torsional rigidity weight for weight.

2) Space-frame chassis. The overall shape of the vehicle is defined by a tubular steel structure to which all of the main components are mounted directly. The body may either be a separate light weight shell or a simple skin fixed directly over the frame. The lotus 7 is a classic example of this type of construction.

This allows for a very stiff but light weight chassis as the size and placement of the tubes within the structure can be specifically designed to distribute the expected loads as efficiently as possible.

The big advantage of this method is that it allows for a very stiff but light structure using relatively low-tech methods. However considerable care is needed to ensure that it is dimensionally accurate, particularly with respect to mounting points for engine, transmission and suspension components. Also fitting up and welding thin wall tube takes a considerable degree of skill and experience.

3) Monocoque construction. The body and chassis of the vehicle are essentially the same structure. This method usually relies on forming some relatively  thin sheet material, usually sheet steel or a composite with most of the stiffness of the structure being derived from its shape.

All else being equal this is usually the lightest construction method for a given stiffness and composite monocoques are the state of the art for high performance and racing vehicles. Pressed steel construction also tend to be the most cost effective for mass produced vehicles.

The downside is that it requires quite sophisticated construction methods. Since you need the ability to make complex 3 dimensional shapes from sheet materials. The tooling to do this is steel is only cost effective for very large volume production and producing composite mouldings with the required degree of accuracy on a small scale is a significant technical challenge.



So overall I would say that a tubular space-frame is probably the most attractive option for decent performance with realistic construction methods.

Chrome-moly steel will give a considerable weight saving over mild steel, although it is tricky stuff to weld effectively. It really needs to be TIG or gas welded.

Aluminium is also a possibility, again it is tricky to weld, requiring an AC TIG machine (expensive) and a certain degree of skill. Aluminium extrusions and tube can be effectively bonded together with epoxy but you will need custom made junctions, you can't just glue it together with butt joints.

[Uncle Arthur]

Here in the U.S. drag race weight fiberglass bodies are available for many old body styles. The first that comes to mind would be the 26 model T roadster. I can grab one up and wander off with one with no real effort. For something like a quad they would be fine. For automotive road use not so good.  On aeither a space frame or ladder frame they would be possibilities for your project.

[akumabito]

The max width of 150cm should not be an obstacle in the slightest - it's nearly the exact same width as my car!

Definitely also look into cyclekarts, at least for the body construction. Plywood mostly, with a dash of fiberglass. Not too heavy, easy to work with and can look plenty nice.

As for the kids' seat - look into dickey/rumble seats. In this part of the world I believe best known for its appearance on Donald Duck's car, lol..
http://en.wikipedia.org/wiki/Rumble_seat

Something else you might be interested in as it's realtively easy, lightweight and cool-looking: The Carson Top:
http://www.rodandcustommagazine.com/howto/86421/index.html

Now start stalking the Jalopy and HAMB message boards for inspiration..

[Uncle Arthur]

OH WOW!! That Carson top brings back memories. I built several when we were doing auto trim.

[bicyclebuilder]

Thanks for the information, people.

Here in the U.S. drag race weight fiberglass bodies are available for many old body styles. The first that comes to mind would be the 26 model T roadster. I can grab one up and wander off with one with no real effort. For something like a quad they would be fine. For automotive road use not so good.  On aeither a space frame or ladder frame they would be possibilities for your project.

I googled "26 T roadster Body" and got this:

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Where does it go from here with a real hotrod? Is this bolted onto a flat chassis?

I like this approach because I would be able to make the modular system of either kid seats or pickup back. I could make the body as a monocoque with front end and back as a space-frame chassis, or a lightweight fiberglass body with space-frame in bitween. What I want to end up with is a bare chassis with a fixed center part. Something like this, without the trunk in the back, and with pedals instead of an engine ofcourse:

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I can weld (haven't done it since school though) but don't have the tools to do so. Either I have to bring a detailed plan to a welder or I have to find another way to construct. Epoxy bonding could be an option. I could try to make the structure out of 45 and 90 degree junctions, so I could use of the shelve joints.

[akumabito]

That last picture is pretty typical of how they're done - most of the old-school rods use a ladder chssis. Pretty much just two frame rails with a few crossmembers.

[bicyclebuilder]

That looks like this construction could be to heavy for a low weight recumbent 4-wheeler. I've found this on youtube. Space frame recumbents made with, what it looks like, standard square tubes with stock joints.

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XYZ SPACEFRAME VEHICLES

However this is easy to manufacture with just a saw and a screwdriver.
I've found a website about a few people who build space frame domes. One of them made a dome with this kind of joints:

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It looks kind of flimsy, but perhaps with the right geometric it might just work.
Another option, and closer to the Steampunk era, would be a space frame, made from wood. I can work with wood, glue it with PE-construction glue and it's ridgid and lightweight.

About the rear wheels, there are conversion kits for trikes (bicycle-trikes)

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There are also ones with a diff, but I couldn't find it on the internet.
found it.

[bicyclebuilder]

double post! I found the front end:

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I've ridden a similair trike before and the position and angle of the front wheels gives you the opportunity to ride no-handed. Downside is that when turning, the rear wheel doesn't follow, so you slow down in corners. I don't know if a second wheel would increase or decrease this problem.
I'm going to go for a front suspension and a ridgid rear axle. A full suspension would add in weight. Big balloon tires would dampen most of the uneven roads.

[akumabito]

In terms of looks, that front suspension is somewhat similar to the Morgan threewheeler and other lightweight pre-war cars. Sliding pillar suspension was pretty common back in the days. In fact, you could make the whole thing look like a Morgan three-wheeler - this would also solve the problem of the back axle - at the expense of seaing for the kid(s) though..

I don't know how much those bicycle diffs go for, but I thought those were pretty expensive. If you're up for doing a little fabrication work, there are axles with diffentials available like these: http://www.northerntool.com/shop/tools/product_35768_35768 - those also take a variety of sprockets, AND can be adapted to both drum and disc brakes..

[Narsil]

It looks like the spaceframe trikes in the youtube video have simple bolted joints, simply drilling and bolting through the tube. This is basically ok but you do lose a lot of stiffness (and thus add weight) with this method. A potential improvement is to fill the end of the tubes where they are bolted either with a piece of square bar which fits closely inside the tube or something like a reinforced epoxy. This will greatly increase the strength and stiffness of the joint, allowing you to use thinner wall tube.

The other option is to find a source of joining pieces, a bit like the junctions used on some rigid pole tents (ey A, Y, X, L, T shaped pieces etc.) It would also be possible to get these fabricated in steel, probably reasonably cheaply. If you mix steel and aluminium you do need to take care about corrosion protection, but this is by no means an insoluble problem, especially if you are bonding the pieces together. You may even be able to find suitable parts off the shelf with a bit of searching.

The other thing to bear in mind is that any project with limited resources tends to shift the goalposts a bit in terms of the optimum solution, so sometimes a  well crafted version of a low tech concept can work better than a compromised version of something high tech.

Also a much of what has been said about basic design concepts applies just as well to wood as to metal alloys and composites, things like, ash, birch ply, spruce and even doped fabric can all be high performance materials in their own right with the right construction methods.

[Uncle Arthur]

I have seen similar space frame units built from electrical conduit. The major caveat here is that most conduit here in the U.S. is galvanized . The use of welding equipment is thus rendered risky at best. There seems to be a large number of connectors though that have assorted angles that may render the use safer and more logical.

[bicyclebuilder]

#SNIP#

The other thing to bear in mind is that any project with limited resources tends to shift the goalposts a bit in terms of the optimum solution, so sometimes a  well crafted version of a low tech concept can work better than a compromised version of something high tech.

Also a much of what has been said about basic design concepts applies just as well to wood as to metal alloys and composites, things like, ash, birch ply, spruce and even doped fabric can all be high performance materials in their own right with the right construction methods.

That's what I'm trying to prevent. I'm trying to find a balance bitween high tech (expensive) solutions and cost efficient but (close to) equal results. I've worked with wood before and find it easy to work with and remarkably strong. The plywood cruiser I've made was at some points over dimensioned. I think for this project I need to do calculations for the structure to keep the structure strong but not to big.

The Morgan cars have wooden frames, resting on a ladder chassis.

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I think, with my design I'm going to keep the doors shut and keep the doors as part of the structure. I might make progress with the sketchup model later today. I'm going to use the Ford model as a guideline for a spaceframe structure. Pics later.

[Angus A Fitziron]

I really like the modern versions of the Model A rod, like the Volvo hot rod:

http://www.babez.de/volvo/volvo-hotrod.php

Chip Fooses modern rod:
http://nnm.ru/blogs/interstate1976/the_modern_hot_rod_chip_foose_coupe/

or Tristan Hopps Mazda concept
http://www.automotto.com/entry/hotrod-concept-blends-classic-hotrods-with-modern-design/

The inclusion of a bonnet / hood covering the 'engine' in the prototype allows you to build a monocoque shell which provides a body and chassis in one structure thus saving weight. In the 60's Jem Marsh was building monocoque body/chassis units for cars - see Marcos - which made use of plywood box sections to give longitudinal and roll stiffness and as a medium you are used to working with, I suggest it worthy of research! Another material you might like to look at is aluminium and aluminium/composite honeycomb sheet. Incredibly stiff and strong and light.

Africar was another project that used plywood as a structural component.
http://www.oldwoodies.com/feature-africar.htm

Interesting project - good luck!

[bicyclebuilder]

Great info Angus, Chip Foose makes some awesome cars!
I've made some progress in modeling:

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For now, the material wil be wooden beams (44x44mm) covered with a plywood sheet to curve the edges.
It's been a while since I worked with Sketchup, but it's starting to come back now.

Now I'm off to see what this Jem Marsh did.

#Edited#
I've found this website.
http://www.americanspeedster.com/side-kick.htm
A pedal car made from pcv tubing. The structure doesn't look ideal, but it could work. Plus I work at a plumbing company, so I could get the tubes with discount.