[sustran] Blowing bicycles

[Kerry Wood]

Dear Milnor

My first reaction to your proposals is that they would need too much power,
especially at the relatively high speeds you propose, so I tried some crude
calculations.

If a bicycle is to be blown along at 40 km/h, the cycling resistance equation in
the CROW manual gives an air speed of some 55 km/h. Taking a minimum cross section
of say 3 m diameter, that gives an air flow of just over 100 cubic metres per
second, or much more uphill. Cyclists will resist the idea of going through a
non-return valve, so the air flow will have to be induced by jets of high pressure
air - noisy and inefficient. I make the frictional pressure loss about 6 cm of
water gauge per kilometre. That puts the frictional losses at about 60 kW per
kilometre, or say at least 250 kW/km allowing for jet losses and both directions.
Air flow could be shut down when there were no cyclists in the section, but this is
still a lot of energy: possibly more than using buses.

I hope this means my figures are wrong.

Do you have any information on power requirements, and construction costs? What
maximum gradient would you expect to be able to manage, at reduced speed?


Regards


--
Kerry Wood  MICE  MIPENZ  MCIT
Transport Consultant
1 McFarlane Street, Wellington 6001, New Zealand
Phone + 64  4  971 5549


"Milnor H. Senior, III" wrote:

> Dear Jain Alok,
>     Please consider that in the air movement powered TransGlide System cycling
> speeds will be 40 km in urban areas which is faster than either bus or rail
> speeds.  Studies show that trip time is the major factor in determining mode
> choice.  By making cycling the fastest mode of transportation in urban areas it
> will attract much greater market segments.  Also, there are electric power

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