NEW YEAR NEW IDEAS

It's been a while since I last visited the blog. I'm still attending college and have gone through several life changing events.

Anyway, I've come up with some new ideas for building a scaled prototype. To save on the cost of material for the prototype I would prefer to use a polyester resin which leaves out regular foam for shaping the prototype. The cost of a urethane foam is too expensive to justify the cost. Therefor, no foam is planned to be used to make the prototype.

Chicken wire, I said it chicken wire is my grand idea. Since a scaled prototype won't be supporting anyone the prototype needs only to inspire more ideas and show the spacial relationship in 3d. I plan to make the prototype with fiberglass over a wood and chicken wire frame. Working with the fiberglass will giving me more hands on experience with the material. Additionally, I'll be able to further work on my body work skills. I'll probably use auto body putty since I'm using using polyester resin. However, any actual velomobile would use epoxy micro putty to smooth the exterior of the body due to the lightness of the material.

I currently don't have any design software. I'll have to try and get more software to redesign and put together an electronic design to save on material when making parts. I recently have lucked out in that my father purchased a MiG welder. I might forgo the expense of buying a gas tank for Argon gas to weld aluminum; we'll see.

Material Research

I have done some thinking and have sided that building with plywood will be more cost effective and yield quicker results. I would love to use a foam technique but the cost of the epoxy would be too costly. Even a honeycomb material would be nice to try and save weight, but that is also more expensive. The local supply of luan (lauan)plywood is horrible with two thin plys on the exterior and one large ply in the middle. The middle ply does not look like a solid ply but some other filler material. However, the birch plywood seems to have even plys throughout the plywood.

Looking at my design, it looks like a slight bend to the panels would add strength and stiffness. Flat panels are easy to join, but are flimsy without any additional stiffing of some sort. After reading more on the stitch and glue technique, it seems feasible. The technique doesn't require any molds or special techniques. It is very reproducible by anyone, as long as the panels are cut correctly. A simple epoxy filler and fiberglass work is needed to cover all the joints for strength.

Velomobile Stitch and Glue

I am trying to make time to work on the seat. Haven't been able to get to my dad's house where the material is. I am guessing I might take a few times to get the seat profile down.

I am thinking about how to apply stitch and glue boat building techniques into velomobile building. For my first project I figure I want to make the body as inexpensive as possible, since I can always reuse the mechanical parts for another velomobile later. I have been thinking of simple but decent shapes for the shell.

I read that the angle on the rear end should be 12 degrees or less. The idea I have drawn up has a 13 degree angle. Pretend there is an imaginary line that extends along the edge of the velomobile and you measure at the point the rear begins to narrow. The angle from the imaginary line to the point the body curves to the rear should be less than 12 degrees, which makes for a long body if it has any width to it.

I drew two lines to represent the angle that is being measured for a visual. Like the old saying goes, a picture is worth a thousand words.

I decided to play with different roof lines to see what kind of effect it gave. A lower roof line in the front gave a pretty neat effect. Will need to verify measurement to see how low the top can comfortably be. I think my ideas are within being able to use the stitch and glue technique. My drawing has a width of 38 inches and a length of over 9 feet. I am hoping to make room for a back seat.

Seat Design/ Building Process

Well, I have been doing some research to make a seat. I want to have a seat that might be used to do some mock ups. I want to do some mock ups to help me better determine space requirements. This is something that could probably be done on the computer, but I have a hands on personality. Besides, building the seat at this stage just means one less thing to build later.

I think I have found a pretty good method for using plywood as the seat material. The process is pretty straight forward. You shape three pieces of plywood to the given contour of the seat and fasten 2x4 in between the three shaped pieces of plywood as a form. The 2x4 run the length and up the sides of the plywood with the 4" sides perpendicular to the plywood/ horizontal. Once the form is built you can make your seat.

You use two or more sheets of plywood to make the seat. Sound like 1/4" plywood was the choice of many builders. You glue the two or more sheets of plywood together and fasten them to the mold with clamps/ straps. Use spare material to place in between the seat and the fastening method of your choice to not scar the seat surface. Make sure the plywood being formed is larger then your desired seat; you will later trim the seat to size.

Let the seat sit an appropriate amount of time for the glue to harden, usually twenty-four hours. You wouldn't want to remove the seat to early and waist all your work.

I am thinking I might make a fiberglass or Kevlar seat later on, Kevlar is just laying around. I might try and put a backseat for my wife or one son to ride with me. I might have to get creative on how to work that out. I am figuring a few extra pounds for a seat wouldn't break me. Besides, the seat can always be made removable.

Forum: http://www.bentrideronline.com/messageboard/showthread.php?t=35802&highlight=plywood+seat

Velomobile Fairing

I was thinking about different methods for building the fairing that might be more easily shaped for an aerodynamic benefit. One method would be to use a foam core that is ruff cut to the desired shape, fiberglass and smoothed. Here is an example that shows someone using foam to shape their bike's exterior in foam. http://www.wisil.recumbents.com/wisil/barracuda/barracudafairing2.htm

Another method would be to build foam ribs and fasten thin strips of foam across the ribs to for the outer shell. A really good example is here: http://www.adventuresofgreg.com/HPB/2006/12/dec-4-2006deck-covering-until-just.html

I think both ideas would work. The rib method would probably be lighter than leaving all the foam in the velomobile, but the extra foam would allow for more impact resistance in the event of an accident. I have to way the difference in safety for weight. The weight penalty should be minimal and this is supposed to be a commuter velomobile.

Rear suspension

Here is a look into the rear suspension. I figured I could either use bushings or bearings for the pivoting point of the suspension. I am not sure what would transfer the least amount of noise to the body of the velomobile. I would think that polyurethane bushings would absorb the impact and disperse any road noise. I am not sure if friction is a critical factor with this part of the suspension. Its not a continuously moving part like the wheel bearings, which require an efficient low friction manner of spinning.

Front Suspension

This is what I have drawn up for the front suspension minus the shock and brakes. I am figuring the steering axis inclination at a 15 degree angle in the diagram. The steering axis inclination is the angle at which the two lines intersect with the bottom patch of tire and the pivoting point of the A-arms. I will do more research on suspension geometry before doing a finally design and mock up. I am trying to keep to simple geometry that should make fabrication easier. I think most of these parts can be built with patients, a drill press and a hacksaw. I will probably use aluminum because it is fairly easy to work with.

Reasonable Top

I figured I would try a different approach on my bubble top idea. I still like the idea of a bubble top, but I would need to build an oven to heat the plastic with. I could always start with no top and then build a simple top that could use the same outline for the bubble top. This would allow for the canopy's to be interchangeable.

I hope to find more people that have home built human powered vehicle and home built velomobile.

Bubble Canopy Velomobile

Well, I decided to play with the idea of a bubble canopy. Ideally, I would make the canopy deeper than in the drawing. I am trying to weight the difference between making the rear wheel enclosed vs being open. With the rear wheel being enclosed it makes tire changes and patches more difficult. An open rear tire is more easily changed or repaired and allows for a trailer to be hitched to the rear drop out, but is less aerodynamic.

The dark area around the canopy would be the hatch that would lift up and forward for the operator to enter/exit. I am exploring the idea of having the main frame being wider (20 inches vs 4 inches) then I originally planned and having a sub frame in the middle for the pedals, seat, and rear suspension. A wider frame approach would allow for more side protection in the event of an accident. I could add foam blocks between the frame and the outer shell of the velomobile, like a modern car bumper for side impact protection.

The down side to a canopy is the greenhouse effect. The canopy would have to be painted on the top to block the sun. A canopy could be made with some simple tools. It should yield an aerodynamic shape with little effort.

Designing

Well, I have been working on designing the velomobile in sketchup. I am having issues manipulating the curves in sketchup to form the complex curves for the nose. I am going to start designing the suspension parts. This will help me further my work, while getting more used to sketchup. Getting used to drawing my ideas on the computer seems to be quicker for some things. It's very nice to be able to turn the item all different directions and rescale without starting over.

I am researching joining IHPVA, International Human Powered Vehicle Association. After reading their web page it seems the organization is along the lines of what I am trying to accomplish. A human powered vehicle to get from one point to another. I am going to try and contact them to see how active the organization is. They have sub chapters around the World, but the nearest one listed on their web page is over a hundred miles away.

Bentrider Online is another resource I might explorer for getting advice. They have some active forums to communicate with.

Drawing Program

Well, I have been doing some of the tutorials for Google Sketchup and it appears to be user friendly. I will have to download the program and try my hand at it. Hopefully I can get it downloaded and start sketching different velomobile ideas, soon. A 3D drawing program will help with figuring out how things can better fit together.

Velomobile frame drawing

This is what my main frame idea will consist of for the velomobile. Two pieces of plywood that run parallel to one another. Then bulk heads made from 1/4 inch plywood and about two inches thick will be made to construct the shape of the sides. The front will most likely by formed in foam to allow for more curvature. I plan to router 3/4 inch groves out of the plywood bulk heads to run more thin strips of clear pine. The thin strips will be flexible enough to blend around the bulkheads.

After the strips of pine are attached an 1/8 inch thick strips of plywood will fill the void between strips of pine. This will give the final outline of the velomobile. Epoxy and a filler material will be filleted along the bulk heads and finished with a layer of fiberglass.

I am looking for a way to draw to scale on the computer. I am researching google sketchup because it is free. I hope to find something more suitable soon, then paint for the velomobile project.

Chain Routing

Attached is an option to route the chain. I want to have a geared hub in the middle to use as a transmission. This will allow for several gear ratios and help keep things simpler around the pedal sprocket. The pedal chain, left chain, would change levels with a idle sprocket, then run to the the geared hub, call it a mid drive, to the point where the rear suspension pivots. This should keep the rear suspension from tightening at pedal start up before any forward movement takes place, at least lesson the movement. A final chain will complete the power transfer to the rear tire sprocket. This is not drawn to scale and is just representative of the idea.

Steering and Suspension

Suspension

One of the first things that need to be decided is what type of suspension and steering mechanism that will be used. I plan on using a double wishbone suspension for the front suspension, unlike most commercially available models which use a McPherson strut assembly. Either design would work, but the double wishbone suspension allows the use of bike shocks. There are a lot of choices when it comes to bike shocks, from adjustable height, dampening, and load.

The double wishbone suspension is going to add weight but will allow more adjustment for the velomobile's suspension. Camber and caster will be adjustable, to an extent, with a double wishbone suspension. By being able to adjust the suspension, the performance and/or life of the tires can be extended. A double wishbone suspension has a lower and upper A arm with a shock attached to either arm.

A double wishbone suspension also allows for the suspension to attached to the main support frame, instead of adding extra support to the top of the wheel well for a McPherson suspension, which would add weight and not be as adjustable. I should be able to bolt everything together, for ease of assembly and fabrication.

Double wish bone suspension

• Adjustable Camber
• Adjustable Caster
• Completely supported by the main frame
• No weld design

Steering

The steering will be either double tiller or a steering bar. Both methods will utilize Ackerman steering. The double tiller allows for a more open feeling with nothing to maneuver around while enter and exiting the vehicle. The steering bar allow for simpler fabrication, less parts to adjust and maintain. The steering bar could pose a safety hazard while exiting the velomobile in an emergency.

The rear suspension will be addressed at a later date. I need to draw some of my ideas on the computer, or find a way to scan my hand drawings.

Velomobile Planning

Well, I am working on ideas for how to build the frame and body of the velomobile. I know I want to use two pieces of plywood for the main frame that will go from the front to back of the vehicle. I will use bulkheads like building a boat and then have thin strips of wood strung across the plywood bulkheads. I will then cut very thin plywood into six inch or smaller strips and attach them to the strips. This method should allow for the curvature of the sides from top to bottom as well as from front to back. Plywood in a larger piece would not bend in more than one direction, hence the cutting into strips. After gluing the plywood strips to the outside, I will sand it smooth and then fiberglass. The fiberglass will then be smoothed and painted.

I plan on making a model at 1/2 scale. The model will be built using full scale material, which should give me an idea of the difficulty working with different material.

Opening

Hello! This is my first post. I want to do an over cap of the velomobile project. I have done a lot of research on ideas for suspension and drivetrain. This is something that has gained interest as a way for me to travel to and from work.

The velomobile must be built mainly of readily available material, wood, fiberglass. Most drivetrain parts will consist of bicycle parts. I have a 500 watt electric assist motor to make the vehicle easier to operate. I want to incorporate working lights and blinkers for safety. It will have a bright color to stick in traffic. Did I mention, this need to be build able. I have a little wood and fiberglass experience, but no design or bike building experience.

Building material

• Wood- Main frame
• Fiberglass
• Aluminum or steel- for suspension parts

Features

• Pedal/ electric assist
• Lights/ blinkers
• Fully enclosed
• Full suspension
• Tadpole layout

I will post building ideas later. I have some drawings I will try to get scanned.