GTO - The Editorial Fairing
Words: Dave Larrington
Pictures: Dave / Tina Larrington
unles otherwise stated
The information contained in "So You Want
To Build An HPV" is extremely useful, but doesn't go into enormous detail.
Since I decided to build a full hard fairing for the Editorial Kingcycle,
I thought I would enlighten you with some of the hows, whys and wherefores.
What do I do with my HPV? I race it and ride
it on the road. Racing is just for "fun" and covers maybe 300 miles in
the whole year. This is equivalent to three weeks of commuting.
What are the disadvantages of commuting with
my present HPV? It's cold in the winter and wet when it rains.
Why not just use my race fairing? It's uncomfortably
tight and sweaty, floppy and fragile, difficult and time-consuming to get
into and out of, and it makes it well-nigh impossible to get into the luggage
Anything else? Yes, luggage space is a bit
limited, especially once you've got all the usual stuff - lock, pump, tools
& spares, waterproof jacket, battery etc. - on board. This makes it
much harder to build a better life by stealing office supplies. And it's
getting old and tatty. Therefore, I want a hard shell. This might even
bring the added advantage of making the bike faster.
The FWD Rotator Coyote
run by Dean Peterson in the 1996 IHSPC. Not much troubled by crosswinds,
Photo: Bill Volk / RCN
Joachim Fuchs' Aeolos
- read all about it at http://www-ifia.fzk.de/personal/fuchs/13.htm
Photo: from the above web site
The Aerolope featured
in the RCN Buyers' Guide
The BumbleBike. If the
likes of Klaus Schlager can use one daily, I don't see why I can't!
Photo: from "Das Liegerad" by Gunnar
Andy Wilkinson's faired
Photo snaffled from the Windcheetah
After much deliberation, the decision
was made to go for a shell with a forward-opening lid. The Aerolope and
Rotator are designed to allow the rider in and out through large side openings,
but you've still got to get your machine in and out, so you may as well
have a (removable) lid, with smaller side openings for hand signals, much
like a faired Speedy. The holes could easily be closed off with fabric
or GRP side-screens for racing or really filthy weather, while the
lid can be left off for sunny day cruising. Important when you need to
work on your tan.
"Design" Process - Part 1
Get a nice accurate scale drawing of the "chassis"
in side elevation. You don't have to go over the top with this, just ensure
all the salient points are present - wheels, seat, steering, bottom bracket
etc. are present. Here's one I prepared earlier:
Measure the position of awkward extremities
of your body while in a riding position. Such things include head, knee,
foot, shoulder, hand and a whole bunch of other stuff you usually forget
first time around. These will define certain fixed points inside which
your fairing cannot go, unless you plan to be either very cramped (e.g.
big lads like Sam Whittingham in small machines like the Varna) or the
subject of major surgery.
Varna Orpheus (38cm wide!)
Photo: Jeff Wills
Depending on the height of your eyes, steering,
knees and bottom bracket, you may find it more practical to have bumps
for your knees and / or feet - examples include Eggert Bülk's machine
at the 1997 World Championships and the Evolvente - to allow you a better
chance of seeing the road.
Decide how much wheel you want sticking out
at the bottom. I went for 1/3 of the diameter of the front wheel,
because it seemed like a good idea at the time. This may change, however,
depending on how much higher my head and shoulders are after fitting a
new seat - the old one had a broken frame and felt very laid-back
compared with the new one!
For a RWD machine, decide whether you want
the rear wheel inside or outside the fairing - inside is easier to build
but harder to get at, unless you don't have a problem with grovelling around
on the floor trying to persuade a recalcitrant wheel through a narrow slot.
How long do you want your tail? Long tails
can impose undue stresses on the rest of the structure, and the aerodynamic
benefits are dubious - whether you subscribe to the theories of Sir Sydney
Camm or Dr. Wunibald Kamm, the principle of the chopped-off tail is well-known.
But if it's all short and stumpy, you'll lose cargo capacity.
Where do you want you windscreen? If it's
close up to your face, it will be more prone to steaming up in cold weather,
and possibly a bit claustrophobic, but if it's somewhere down the sharp
end, seeing out in the wet could be a problem, and operating a wiper more
difficult. A ready-made NACA duct with a dinky little deflector lip - as
used on Nigel Sleigh's Plastic Maggot - can be purchased from car accessory
shops of the "Max Power" variety and can blow air up the inside of the
Nigel Sleigh's Plastic
Photo: Jonathan Woolrich
"Design" Process - Part 2
Once all the above has been sorted, you should
be able to come up with a nice side elevation of your proposed machine.
In order to get the curves right on the plug,
you will need to measure the vertical distance between some hypothetical
baseline and the curve in question. Repeat at suitable intervals for the
duration of the curve.
Then you will need to do a plan view, and
front and rear elevations. It's probably for the best if you make this
symmetrical about a longitudinal axis. The ends will come more or less
by default (mine did, anyway). For mounting lights and other bits and bobs,
you might feel the need for a reasonably uncurved area to avoid unsightly
Ensure that the fairing is wide enough to
fit both your machine and yourself inside, comfortably. Small may be beautiful,
but if you're planning to spend a lot of time inside, slightly-larger is
Important dimensions include the width of
the shoulders, separation of the hands (allow some extra space for turning
the bars), seat width and width at the pedals. If you use clipless pedals,
ensure that there's adequate space to twist your foot enough to unclip
yourself, as you will look silly if you have to unfasten your shoe every
time you want to put a foot down.
If you are intending to use "bomb doors" for
your feet, rather than holes (and bomb doors are much sexier), you
had better ensure that the ground clearance is sufficient to allow them
to open fully. You didn't?
If, like me, you want to be able to extract
the rear wheel without a prolonged fight, you will need a wheel arch with
adequate space for hands, freewheels and other nasties to be able to co-exist
in harmony. This dictated a wide rear end (oo-er, Missus!), but also meant
that I could utilise the vertical panel above the opening for a "hatchback".
There's little point in having plenty of carrying capacity if you can't
reach it. It may also prove sensible to divide the general behind-the-seat
area into smaller spaces, with plywood, Corriboard or somesuch. Ensure
that however you divide it up, you can actually
reach the furthest
extremities thereof without turning the bike upside down and shaking it
vigorously, as that spot is precisely where your tool kit will end
up when you have a puncture.
Congratulations! You now know precisely what
the finished article will look like (irony)! Recheck all dimensions
carefully, and write them on the drawings, so you don't mess up later.
Too small, and your machine will be unridable; too large and it will not
fit in your shed. Both are Bad, and should be avoided.
There's no need to go over the top with the
accuracy of the drawings, unless you're building a record-brekaer and/or
are capable of marking out a line over 2m long, drawn with a Magic Marker,
with that kind of precision. I wasn't, and I'm not.
I reckon that using some kind of computer
program will make life a lot easier, though you will be limited to 1:10
scale unless you have access to a weapons-grade printer. I used TurboCAD,
from Imsi, which came free with my father's PC. I also used, for some bits,
a little Windows program called "Optimum Fairing Design", by Warren Lemoi
(downloadable from this site). This
does all the hard sums on pp 100-103 of "Bicycling Science" and gives you
a series of x-y co-ordinates which you can input into your CAD program
or pencil. It kept crashing when I tried to print the listing (under Windows
'95), but apart from that it works fine.
Saturday January 17th(1999)
Curses! Due to the odd shape of the CX
Safari's roof, my roof bars won't fit. B&Q can only deliver to our
area on "Monday". No, they can't be any more specific than that. Buy other
things and go home to think.
Saturday January 24th
After a week spent investigating the cost
of trailer and van rental, a brainwave and some bodging (Imperial nuts
onto metric bolts, anyone?) sees the roof bars and Moby firmly conjoined.
And what a stirring sight he made with twelve 2" sheets of 8'x4' insulating
board on the roof. If you're planning on doing this, try to pick a day
a howling north-easterly gale. Haul down boards and stuff in shed, pending
purchase of hot wire cutting tool and gas bottle for stove to heat conservatory
(my enforced "workshop" space).
Saturday January 31st
Hot wire tool and gas bottle obtained.
Sit down in nice warm conservatory and practice cutting up off-cuts
of Jablite we actually bought for its insulating properties. Hmm, not as
easy as it seems.
Sunday February 1st
Drag first sheet out of shed. Cut large
lumps off it so as to make it easier to handle. Oops, too large.
Never mind, we can re-use that one for one of the "outer" pieces. Drag
second sheet out of shed. Trim more sensibly. With tape measure, set square,
pair of compasses, various bits of wood and a ruler discovered in the shed
which is exactly the same length as the main part of the fairing
is high, mark out the first sheet. Start cutting. Knock sheet off Workmate.
Sheet lands on the floor with wood, cutting tool and extension lead on
top of it. It breaks into two pieces. Harsh words are said. Repeat from
"Drag second sheet." until dinner time sets in. So far have filled
six bin-liners with scrap foam.
The Rest Of February And Well Into March
Continue to mark out remaining sheets.
Progress is slow due to:
A bout of gastric flu which left me unable
to do anything very much for about a fortnight
The fact that the conservatory is a little
too narrow to allow a complete slab inside so as to be able to cut it roughly
to size. So it has to be done outside - tricky when it's dark, raining
and blowing a gale
A partially-Edited sheet
of insulation foam. Note vast size of workshop...
However, once this is out of the way, progress
be made. Watch this space for more details!