I like Trikes, and I like Crank-Forward design

[SimpleSimon]

So, after looking at some of the designs on the RANS site, I thought I'd return to my endeavors in sketching up bike designs. Here's my interpretation of a crank-forward delta trike. As drawn, 26" rear wheels, and 20" inch front. This is a bare bones frame idea, which will lend itself to variations. Dropout sizing is 5 3/8", intended for one of the various internally geared multi-speed hubs as a mid-drive, then final drive chain loops from sprockets mounted to each of the spoke flanges of the mid-drive hub to freewheel sprockets on the inner ends of the half-axles. As envisioned, it would get dual disc brakes at the rear, on the inner ends of the support tubes for the half-axles.

I intend to do further sketching, first re-sizing the dropours for a NuVinci hub, and adding an engine/jackshaft behind the axle to put power through the secondary input sprocket available on the NuVinci. When I get that sketch done I'll post it here.

I've also run across a source for the ultra-high compression wound carbon fiber air tanks that are being used for an air powered car in Europe. With the right pressure reduction valving and a 2HP air motor, (plus a compressor that can fill those tanks at home), it ought to be possible to build a motorized bike whose only emission in use is air. By my very rough figures, one of those tanks would give you 30 mph capability and range of about 40 miles, with a 350 vehicle/rider load.

 

[SimpleSimon]

Try again.

 

[GearNut]

I like your frame design and drive train ideas.
Concerning the compressed air system, what psi would the storage tank be at?

 

[SimpleSimon]

4,800 psi.

The tanks were developed for NASA's use in the Shuttle, and are about the size of a 1/2 size standard welding gas bottle, but weigh only 14 pounds empty.

 

[fasteddy]

Simon, do you know how much the tanks are?
What size commpressor would you need?

Steve.

 

[SimpleSimon]

The tanks aren't cheap, rhat I know, although I have not yet gotten a reply to my inquiry as to price. The ones I found a guy has as surplus from NASA, but the tank design is standardized. The compressor to fill them would be the biggest issue, as it is at least a two-stage and possibly a three stage compressor to reach that level of pressurization - those things are NEVER, EVER cheap.

It's an idea, not something I'll ever lilely have the resources to implement.

Here is one example of the type of auto using an airmotor that I am referring to: http://www.popularmechanics.com/automotive/new_cars/4251491.html As referenced in that article, apparently Airbus builds the tanks for MDI, in Luxembourg. Mostly, to me, it is an interesting notion indeed.

 

[GearNut]

4,800 psi??!! Wow! My compressor will only go up to 120, a tad bit shy I'm afraid....