Tuesday, July 20, 2010

I know, sad. I used canvastastic- a free demo version that imitates MS Paint.
Sad thing is that my bud Sanjay let me try Pro Engineer 2000 a few years ago, and I never used it.
I'll still need to learn it before building the Mark I.

OK, so the pic is of the Mark I (version 2) that I wish to build.
The hideous blue squiggly lines represent the general contour of a top/bottom partial fairing.
The grey parts represent the basic frame sans fairing.
I think the lower fairing may be of fiberglass or carbon fiber, and just left attached to the bike frame.
The implied fairing on the nose cone and tail box would just be lycra.
I might use pvc pipe ribs bent in a contour like an umbrella.
The Schlumph bottom bracket drive requires room for the foot to press the button.
A version that allows use of handlebar-mounted shifters would be convenient in some cases.

The fairing has the benefit of keeping the sun and weather and cold away from the rider.
However, a high ambient air temperature plus humidity will cause overheating problems.

I either need air inlets in the fairing, or the option to lower the front half to just above the knees.
Opening a vent in the tip of the nose cone would also remove an air pressure peak point.
I'm not sure how a flat fairing will actually fare in a drag test.

If the fairing is unipiece on top, and can be lowered along with the seat rear to allow a much lower profile, then the bike has
the potential to go very fast downhill with the right drive/ gear hub combo.
This has no practical application for a touring bike.
But if the bike can go that fast, then I would be afraid of crashing.
Then deforming aluminum fairing struts instead of light pvc pipe (for a mockup) would look good.
Also, the idea of the seat back/rucksack on mount securing me with the shoulder straps starts to look good.

Why bother making a short wheelbase with a long wheelbase long wheelbase, but with the pedals out front?
Cargo behind the rider. Good highracer profile. Plays well with a fairing tapering behind the rider.

One I realized the chain-thru-body-tube layout was off centre, a thudbuster could be mounted in a standard fashion in the centre. I am pondering just getting this really wide fat-ass granny seat from the bike shop.

I think in low-fairing/seat-way-back racing mode, that the thudbuster would need to be locked or removed.
The seat, being free floating, would bang on the box frame on top of the rear bike rack.

An Alice pack or other external frame backpack will face a lot of strain at the base, where it mounts to the seat rear apparatus.
I would fear it shearing while riding it. It will likely need to be reinforced considerably.
Note that all cargo must be removed from the alice pack for it to recline greatly.
Alternatively, the box mounted on the rear bike rack would need to be removable.

Can Pantour tire shocks be used to address road vibrations?

D: at 150 for a hub, not so bad.
The main issue is that they preclude stuff like a motor assist hub or a dynamo hub.
Plus I would fear the elastomer would harden in cold temperatures.

One way to address this is to mount the dynamo in the bike frame.
This works better if the chain is laid out internally like the Greenmachine.
And the frame has a suspension point for the rear tire.
Really, an entirely different beast.

Thinking about the idea of an off-centre bike frame mass distribution, I realized that 2 very heavy tubes to the left and right of centre, and just a sheet metal bit to cover the lower chain would keep the weight balanced.
The sheet metal would provide some rigidity.
However, I may still go for 2 on the right housing the chain and one heavy one on the right.
All connected with struts for rigidity.

I don't wish to tinker with 'natural' chainlines, beyond raising it above the front wheel on return.

A motor assist that does not involve the front tire hub could still mesh with the pantour.

Too bad Shimano is sitting on the internal bottom bracket dynamo...


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Dino Snider said...

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