Showing posts with label bicycle prototypes. Show all posts
Showing posts with label bicycle prototypes. Show all posts

Thursday, November 15, 2007

Fairings - HPVs, Tub bikes

I'd like to thank Reg Rodaro and the folks who put up the WISIL site, http://www.recumbents.com/home.asp and all of those links to the world of data presented in such fine fashion. My gratitude and blessings go out to you.
Mail conversations with Reg have solidified my attitude toward prototyping in weldable plastic with a hot air welder. The proto also took mental form along with the goal. Mainly, to pattern in flat sheets a "tub" bike(using their language) or as I refer to it as, an External Frame-Fairing. I'll use clear plastic of thin sheets to see how thin I can really go, while utilizing a cable tensioner to run throughout the structure and "pull" it together. Else, another approach will be to utilize thin, like material tubes to "hold" compound shapes. (Tension or Compression?) The purpose of this experiment is to find a way to lower the weight of full faired vehicles while not using an internal frame and to improve the strength of the total vehicle.
Currently, a full faired vehicle is acceptable coming in at fifty pounds or so, for practical daily use.
My foundation for this approach goes to Bucky Fuller and Kenneth Snelson for tensegrity. May I forward your thoughts and artifactual foresight into this art-in-fact.

Tuesday, October 23, 2007

Fairings - Human Powered Vehicles (conti)

Okay! Been to the supplier - got the fact sheet. Priced plastics hot air welder - basic. The end result design doesn't overlay the beginning or the middle design. Hmmm. Is this a real problem for now? Does the material drive the process? Don't think so. It has to be the mathematics which drive it. The structure, or lack of structure as the case may be in this instance. Keep it simple. I don't need the full body at this point. All I need is the external side panels, the size of wheels, crank assembly, tensional cable, turnbuckles, seat, geartrain, and, oh yes, let's not forget the steering wheel assembly. Contact supplier for raw materials list, availability and so forth. Go down and clean up the workroom. Cut up old bikes and so forth. Clear the area and set up for plastics.

Wednesday, October 17, 2007

Plastic Fairings

I wish to thank TDL Plastic's Cody Banks for the help given in researching material for the fairing. This person allowed me to bounce stuff off which may be only theoretical but took it with enthusiasm and good patience.
Indeed, with all of the changes in the world of plastics, polycarbonate still comes out on top for this design. The minus twenty Fahrenheit brittleness comes into play but may be overcome with metal infusion into the design(?).
Hmmm.
Metal mechanical connectors for the PC panels.
Hollow rivets with washers?
Panels sliding in tracks distorting shape?
The concepts/??????? are coming too fast for now. Have to go. Go with the flow.

Wednesday, October 10, 2007

Fairings - Human Powered Vehicles

Don't remember where my head was on the Plexiglas material. Long ago I had moved on to polycarbonate. Floating out there, sometimes you just latch onto whatever piece of flotsam comes by, and then you realize, after a bit of research, hey, I've already looked at this!
Running down a supplier today, cleaning up the workshop, etc,,,. Trying to pick the material type, thickness, pick out available tools, shapes to use and so forth. Think I'll have to go toward tensional setup instead of the hardback. That'll be interesting, and mind expanding. Onward. Winter's coming. Anticipation is building as to the fun!

Tuesday, October 9, 2007

Conceptualizing Bikes

In summary, the questions are, from a user's point of view, what do we need for our use? What does it need to do? How can it enhance my life? What will it cost? How can one pay for it?
From a designer's point of view, the questions are: What is the "need"? Is there one design which can fulfill the "need" or are there multiple adaptations from a central platform? What are the environmental parameters for the object? What are the environmental needs of the human operator? And, so forth,,,.
It all comes down to the; What? When? How? Why? Where?
Then, we place the word, "Need" into the word equation; Need What? Need When? Need How? Need Why? Need Where? We can rearrange the order as to their logical sequences or not. Or, we can just try and answer the questions.
As most of the science has already been done, "the math" so to speak, pertaining to the efficiencies of the wheel and being able to move objects using one or two wheels, I think I'll not challenge anything in those categories. Nor do I need to address the "Need" part. That's fairly evident.
I think I'll just put this on a personal basis. Right now, I "need" a vehicle that is cheap to operate; is fairly safe; can haul a load of fifty pounds or more; can go up and down hills in the most efficient manner possible; can get me out of the weather; can allow me to go large distances if the need arises; is self locking; is highly visible; is cheap to make. Let's see if I can think of something else to throw into the pot? Oh, yeah, and can either expand or interconnect with another like vehicle to allow another person or two or more to safely travel together. Drafting? Wouldn't that be something? If you could somehow "hook up" behind someone and then actually add your power to theirs? Sort of like flying a tanker? Could you actually make something which would allow a person to run up behind another like bike and hook into a connection that would raise the front wheel off of the ground while providing a solid connection between frames? Now that would be really tricky! But, fun! And, if it were to occur with two or more fairings, you could really put out some serious torque! Or, just use less energy to get to where you are going. Okay, back down to Earth.
Can I make a bike out of a fairing, without the bike insert? Just use the fairing material to be the frame? Can I do this cheaply? If I could use the KSS boat building method to produce a fairing, why not just take available plastic sheets on the market and make them into a fairing shortcutting around the laying out of the FRP and vacuum pumps and all of that costly process? Could I take, say, Plexiglas, and using the cables and so forth, bend it into a fairing and then using a solvent, melt the fiberglass onto the plexi? Or, once bent into the shape I need, hit it with a heat gun and "set the shape"? Once in a shape, I could string the tensioning cables inside to form the seat, seat back, and longitudinal tensioner hooking the axle/drivetrain/crank arms into a tensional unit. Okay, I think I'm onto something here. Off I go to research.

Tuesday, October 2, 2007

Imagining Bikes - Biking Minnesota

It has been stated that to try and forecast the weather in Minnesota due to three climate systems coming together in the middle of the state is like a crap shoot. Now, throw in the effects of climate shift and, boy-oh-boy, it is any one's guess. My Dad, who was a meteorologist, used to be able to predict locally based upon the lay of the land when they lived in southern Georgia. I think this place would have challenged him greatly.
Working outside in the Western U.S. for around four to five years, frequently in the middle of nowhere, forced me to carry three sets of clothes and two sets of foot ware along with other necessary survival gear for any type of weather conditions, plus a sleeping bag. One even stashed emergency rations anywhere and everywhere.
Your experiences should teach you to plan for overcoming the last miserable challenge and your survival may depend upon being able to effectively imagine the possibilities. One hopefully learns to overcome the circumstances and learns to use the past similar to tools in the toolbox. Of course, one can't afford to lug around all fixes to all possibilities so one must melt it all down to the smallest possible denominator - what can one afford to carry with one's self? What will it cost in weight? How does it perform in the worst conditions of cold, wet, dark and muddy? And, if your tools fail you or can't do the job with those tools? What if the whole thing is out of commission? Can you effectively carry it or push it?
I rode for years in all types of situations, mostly on the safety. Then, I learned on both the long wheeled base recumbent after an experience on a short wheeled base recumbent. Before those times, I had the situation of having to ride a tadpole trike both with, and without, a front fairing through winters.
There are drawbacks to every available model out there, but none that can't be overcome. Just like life.
I would like to take this time and space to acknowledge a friend who built many of the recumbent bikes and trikes I've ridden over the years and who has been a mentor, employer and business partner, Dave Krafft. It was while working with Dave on his housing makeover that we fixed his long wheel based single tube recumbent model after the tubing we had bought had failed due to the thin walled material. He was going to cut the failed part out and braze a thicker walled tube into the frame when I stopped him and proposed an alternative. (Here is where the oilfield experiences kicked in.) I told him to just put a steel cable between the front crank and the rear crank housing with a turnbuckle, and take the stress off of the tube. A trip to the hardware store, a little metal fab and it was ready for service.
We didn't just end up fixing a collapsed tube. Four prototypes readily proved we had found a solution to the dilemma of frame flex robbing power to the drive train and a host of other problems such as pogoing for that model frame and controlling frame flexure along vertical and horizontal lines without adding member framing, i.e. weight. With the long wheel based (LWB) single tube model, my feeling was that the frame became the suspension. We had to repair the hardware parts many times until we upgraded to better fixtures and cables, plus we learned we had to run the cables all the way to the back to be more effective.
Since those days, both studying why these things worked and other people's art/science of structure, I've come away with more understanding and have built a model applying these same principles to the upright, or safety bike. It works the same as far as I can tell. The biggest kick comes from understanding that the frame can be "tuned" to fit the riders weight at the time. Want a cushier ride, just loosen the frame up.
On a test ride for our first redone prototype, I alarmed Dave when I took these horrendous railroad tracks crossing the street full bore. I mean, these holes around the tracks could flatten your tire and twist your frame into a pretzel! But, nary a thing happened. I didn't even get thrown off of the bike. The bike ran true. The same for hitting sand on the trail. You just aim the bike and power through it.
Now that I've read Buckminster Fuller and viewed the work of Kenneth Snelsen, I find it completely remarkable that no one has understood basic physics when it can be applied to the problem of frame flexure for bikes or other structures. It is all about force vectoring. There was another gentleman that pioneered "tortured plywood" in building catamarans on the West Coast back in the Fifties. I think "Pile" was his name? It's the same principle. You build in, or apply force which can't be overcome by the motion which gives you the problem to begin with. Of course, one has to make sure that the structural member has enough strength range to endure the problems it will face later on through use.
Imagine an upside down bow. The connecting tubes between the front wheels and the rear wheels(axle) are now held in tension with the rider sitting on the top of the compressive member. The more movement vertically results in more compression which results in tension. As the tube at static has very little bend, it is just seeking to return to its' normal condition. The rider's weight(gravity) is counteracting the bending moment of applied tension. Place an adjustable connecting member underneath the rider, and now you have two triangles between two wheels, which give ever so slightly. I refer to it as using the frame for the suspension system.