Squid-in-Training said:Okay so I'm doing a HPV project at my university. We're looking for several
things:
A concept project vehicle, not a production-intended unit for use by
an average rider? Been done, countless times. You have much research
to do into prior attempts, grasshopper.
Quoted message said:1. Fast (and efficient)
Been done, still being done, evidence abounds on the floor at any bike
shop, for reasonable definitions of "efficient".
Quoted message said:2. Big wheels (to go fast)
Not a needed criteria unless you're aiming for speeds over 100mph,
which is also not a useful target. Existing art indicates that for
common human-achievable speeds, current common bike wheel sizes are
sometimes larger than really needed.
Quoted message said:3. Tandem (to go fast)
Not necessarily relevant. Two engines typically don't achieve much
more than one in this arena.
Quoted message said:4. Strong (so it doesn't fall apart)
Well, duh, but you haven't stated what kind of riding parameters are
proposed; for smooth level pavement, this is trivially easy.
Quoted message said:5. Somewhat light (less than 100lb)
Shoot for under 35 lbs for a tandem, or under 20 lbs for a single,
with full fairing, and you'll get some attention. Under 100 lbs is a
criterion that was bettered before 1890 even for a tandem bike.
Quoted message said:6. Modular (we have riders at 5'5" and riders at 6'2" that will have to ride
the bike)
Adjustable frame? Possible, but introduces a great deal of fragility
and complexity to the design which impedes efficiency.
Quoted message said:There's a bunch more but I'm going to be polling the NG a whole lot in the
next couple days.
My questions:
1. What kind of bike should it be? Are bents faster overall? Is semi-bent
a good idea? The riders will be experienced riders that are used to
traditional frames.
2. What kind of tubing diameters should we be ordering? 1 1/4? 1 1/8? 2?
3. What kind of designs employ 700c wheels front and rear on a tandem bent?
How can we get that to work with shorter riders?
You need to cruise the sites that detail the history of the HPV
projects that have come before, and then hit the books in the
libraries and archives of the enthusiast groups and competition
arbiters to see what has already been achieved. Omit this groundwork,
and you are committing to making the same mistakes that have been made
and overcome in the past.
The modern bicycle is a mature product of a great deal of practical
experimentation over more than a century of time. Extreme variants
designed for special tasks (raw speed, speed with duration, raw speed
without regard to wind resistance, etc) have been made many times. A
bicycle was used to break the 100mph barrier (riding in a moving
enclosure) more than 50 years ago. Bicycles capable of allowing a
single rider to exceed 70mph regularly in open air have been built a
number of times. The bikes used in the Race Across America, an
extreme endurance race, are nothing as exotic as you might suppose.
You'll note the conspicuous lack of URLs and cites in the statements
above. This is supposed to be *your* research project, not mine. In
my opinion, the criteria you have set forward demonstrate that you've
skipped the essential first step in any such project; seeing where the
rest of the world has already taken this, and finding out what worked,
and what still needed more work. Materials change, tech changes,
people with new ideas come along...there's still plenty of opportunity
for innovation and improvement in bike design. If you are not to
simply repeat the mistakes of the past, however, you need to start
with an understanding of it, and then devise your specs to take
advantage of what you know at that point.
--
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