Quote:
Originally Posted by visionary
Thoughts about landing wheel design
based upon your last post I have the following observations
Design to fail-safe. Using a powered down spring design risks wheels deploying during use with potentially dangerous outcome in the event of a mechanism failure. Here in UK it is mandatory for stand mechanism to be sprung into retracted position (probably same in US) for reasons of safety.
Design for simplicity. Involving air power requires additional components (and mass)plus delays in deployment over a mechanical system. Also the synergy of use a "shock absorber" is in response to what percieved need? Test a simple prototype first before building a complex version - you may not have a problem to overcome!
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Thanks for your input, Pete. I’ve been fallowing your project with great interest in the hopes of enhancing my own ideas.
Possible loss of air pressure during a turn is something I did not consider, but needs to be addressed with my design. I was thinking about electrical or pneumatic failure not allowing the outriggers to go down, causing an inevitable slow speed crash. I feel I must keep the spring down aspect of the design for this, and the following reason. If the vehicle sits in my garage all night, I don’t want to have to maintain pressure or power to keep it from falling over.
To keep pressure loss from causing the outriggers to go down unexpectedly, I think I will lock the non-pressurized portion of the double action cylinder up by closing its valve on delay. This is what I was planning to do on the lowering anyway, so it’s just a control wiring change. The outriggers would not be allowed to fall completely in this case. I will lose my automatic dropping upon power loss feature, but this seems worth it in the interests of safety.
Ken makes a great point about seating position and use of legs. I found in mock-ups with my low seat, that it would be impractical to use my feet to hold up the bike. The other issue is water tightness; we have a lot of cold wet roads in Oregon so a door would be necessary to meet the goals of the project (comfort). Any sort of door would make it cumbersome in an emergency to lower a leg.
I considered using a linear actuator or a motor of some other kind like the Monotracer and I presume the Electric Enclosed Motorcycle does. I could not find anything that was readily available, fast, and inexpensive. I’m sure Peravis has a supplier who is happy to provide them with large quantities of specialized products at high prices.
This is the reason I came to pneumatics. Parts are easy to find, cheap, and the outriggers will come down as fast as I want them to. I do not like the complication added to a project I swore would be kept as simple as possible, but I could not come up with anything else….That being said I love new ideas. I actually drew up something very similar to Ken’s design, but seeing how I have no hands or feet free to operate anything manually, I passed on to the next.
As for how my project is going now, I am currently on budget and waiting for my square tubing bending die. I will be making bending templates this weekend. The 2000 dollar goal I do not consider unreasonable. The only thing I’m worried about cost wise is the windshield. I find myself doubting my (nonexistent) abilities to mold Lexan, and will probably hire it out. I have not gotten an estimate yet because I’m afraid….