Advanced HPV Project
Why don't more people use bikes? Some reasons frequently given:
- It's hard work
- You get wet
- It isn't safe in traffic
- You can fall off
All of these are valid in some degree. I have had in mind for some time
a project for an advanced human-powered vehicle (AHPV) which will
attempt to address these as far as possible. It is all ideas on
paper at the moment, but I'll go through these problems, not in
order, and suggest how they might be approached.
It's hard work
Well, inevitably it's work. How hard it is depends.
Most people can manage to produce up to 100W on a bike without too much
difficulty.
Using my
cycle power calculator
we can generate some typical performance figures for this amount
of power.
With no headwind on a flat road 100W will move you at about 25km/h,
about 16mph. A headwind reduces your speed by a corresponding
amount, so a 10mph (16km/h, Beaufort force 3) headwind will drop
your speed to a slow 9km/hr. Brisk walking speed is about 6.5km/hr,
below which speed some people find it hard to maintain balance,
so to keep going at this power input your maximum headwind is
about 18.5km/hr.
With no headwind 100W will take you up an `easy' climb of 1:50
at 15km/hr, still quite a reasonable cycling speed.
You will be able to keep going at 6.5km/hr for steeper gradients
up to 1:17, which is actually quite steep. A really steep hill
of 1:10 will drop your speed to less than 4km/hr.
To alleviate these problems:
- Go up hills more slowly - requiring >2 wheels?
- Streamline
- Fit auxilliary electric motor
You get wet
Until the 1950s motorbikes looked more or less like pedal bikes with motors.
Along came the motorscooter which provided a minimum of protection from water
from below and from the front. Bike and scooter technology has now converged
in aerodynamically designed, lightweight fairings which keep much more
water off you as well as providing streamlining (see above).
With modern materials there is no reason why you can't have these on
an HPV.
You can fall off
Most people can learn not to fall off a bike above about 5km/hr,
although some never do, and others have problems at low speeds.
Apart from dynamic stabilisation with gyros, the only answer is to
fit more wheels to give you a trike or a quad.
It isn't safe in traffic
I find it hard to argue with this, as I gave up cycling in Edinburgh several
years ago for just this reason, and now normally cycle only on quiet country roads.
There is no doubt that cyclists are vulnerable in both city traffic and
main roads. The provision of cycle lanes is erratic, cars park in them
in cities and they are often too narrow.
Making an HPV visible, giving it protruberences (scythes on the wheels?)
etc., can help. Recumbents always seem to me to be particularly vulnerable, but a longer and slightly wider vehicle may
be be safer. However, if anything does hit it, a vehicle that
is by definition ultra-lightweight is always going to be
in trouble.
No real solution other than separation of HPV and motorised traffic.
Other Issues
Other reasons why people find bikes inconvenient is a lack of carrying
capacity, either for goods or a passenger.
The AHPV should have the option of being a 2-person vehicle.
Proposed Design Specification
- 3 wheel vehicle
- Weather protection and streamlining
- 1 and 2 person design
- Optional electric assist
Link Collection
These are a few links of general relevance and ideas-sources.
More detailed links will appear on the sub-pages as I develop them.