[Velomobile] Velomobile design

[David M. Eggleston]

   Following John Tetz’s plea for us to get together and work on the future of velomobiles, I’ve enjoyed reading your contributions. Here is my two cents worth.
   From an engineering point of view, velomobile design has to start out conceptually with a list of specifications that the final vehicle must satisfy. Nobody seems to do this on paper, but one can back-figure what the specifications are that the final vehicle satisfies or fails to satisfy when it is tested. Velomobile design has to deal with almost all of the problems that must be solved in the design of a small car. It is a long list, but speed, low noise, cushy ride, weather and crash protection, stability and handling qualities, the ability to stop quickly and safely, power efficiency, ease of ingress and egress, cost, convenience, ease of maintenance, cost of parts, etc. are some of the requirements. Velos are used for commuting, shopping, long tours, recreational day rides, running errands, racing, etc. Some machines are designed specifically for racing, with little or no thought given to other uses. Some velos are quite capable of a whole range of tasks, while others are best for only one or two types of use. An all-around velo has a better chance of commercial success than one that is only good for a few things. Owning many velos is too expensive. Carrying bulky objects is best done with a specialized vehicle or a velo with a cargo trailer.
   You can fairly easily put an aero body on an existing unsuspended trike, but you are likely to end up with many difficulties, including body attachments to the trike, noise of thin shells vibrating, and many others. Chief among these may be that when the aerodynamics are great and you can go really fast, not having a suspension can be mighty uncomfortable. It is likely to result in the rider getting lots of reasons to upgrade to a well-designed (and expensive) velomobile. So you can “cheat” on any of the design requirements up to a point, but the ones that riders want will come back to haunt you if your velo doesn’t have them.
   I harken back to the day that the Tempelman shop opened in Dronten in the Netherlands. Johan Vrielink, chief of Flevobike, came up, put his hand on my shoulder, and said “Building velomobiles is the hardest thing I have ever done in my life.” Over the years, I have come to realize the truth of this statement. There have been tremendous numbers of dream velos that never come to fruition because of this fact. Getting a design “frozen” and getting it into production is quite difficult. The market is ephemeral so raising money for a big production run is really hard. All VM manufacturers hope that Ford or General Motors or Toyota will never understand the wonderful future for the world full of velomobiles, and so far, the companies never have. 
   This means that a velomobile association could combine resources and apply the least expensive of auto design techniques, software, and testing to improve velomobiles. There is a broad range of technologies applicable to velos. You can perhaps imagine a design group equipped with all the latest computer design tools and testing capabilities switching their focus from engine-powered cars to human-powered cars.
Velomobiles need structural analysis, braking and stability studies, suspension improvements, electrical system upgrades, and production manufacturing techniques to lower their cost, among other things. We can go after the “low-hanging” fruit, as it were. In the wings are ideas for tandem velos, special cargo trailers and associated velo attachments, power trailers, power assists, and a host of other technical issues that need design, development, testing and evaluation, production expertise, and marketing.
    A great deal of experience was gained with the velos that were used on ROAM . Stability with regard to rumble strips, braking for descending mountain passes, gearing that allows high speeds downhill but very low speeds up steep hills, shifting systems that enable going smoothly from your highest gear downhill to your lowest gear going up the next steep hill, drive trains that do not drop chains, even when backing, etc. Many of us spent much time replacing brake drum plates, brake disks, tires and tubes, and other parts.  We had four velos roll over, mostly on rumble strips. Nobody was badly hurt, but one was damaged so much that the rider retired and went home. Another velo was put out of commission by a deep pothole in the Chicago area, and one was knocked over by an SUV in D.C.  I could have a whole discussion (along with Frederick) regarding incidents and our experiences with the “ground loop” instability of tadpole trikes. Following advice on tires and rims by Ian Sims, David Gordon Wilson, and Ymte Sybrandy we at VMUSA opted to use Marathon Plus tires on the rear of our tadpole trikes. They are thick and heavy and hard to mount, which is just what is needed so they don’t blow out and tend to stay on the rims even when deflated. Nobody will use them for racing or very fast recreational rides, but they are great for safety.
I look forward to working with others that can contribute to solving some of these problems. I see my most immediate contributions in the areas of dynamic simulation, vehicle systems testing and analysis, work towards improved suspension and braking, and drive train improvements. The work of Bill Patterson and others should be of great help in these efforts.
   I guess we will have to rely on our own ideas and resources for low-budget design and development paths. The realization of all the things we want for velos would cost millions, and it is not clear that such funds will ever be available. The cost spectrum ranges from about $4000 to $25,000 for velos now extant. Prices for materials and hardware are steadily increasing. The goal of inexpensive velos that have the advanced features we want is going to be really , really difficult. Low cost velos presuppose major investments in design, development, testing, manufacturing, and marketing. Who will find the money is a big question. And only those project managers that are real velo riders and racers with be able to “thread the needle” through all the development and commercial pitfalls to get a successful and long-term valued product.

David

David M. Eggleston
VelomobileUSA, LLC  
Midland, TX