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Building the Orange II Velomobile |
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By Brad Teubner |
4/20/08
I’ve got over twenty miles on the new trike,
so it is time to publish the results and claim success. I intend to
paint it eventually, and the raw materials for an orange fairing are on
hand.
The plan was to build a "best of" several other bikes/trikes that I own
or have owned. It was sketched out in a simple CAD program, and parts
fabricated from there.
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It has a Ross seat and
eventually, it will be faired similarly to
my Speed Ross. My Ross is the fastest and most comfortable bike I've
ever owned. |
I simplified
the Orange Varna geometry and
driveline. Ray Brick did an incredible job designing that driveline, and
I didn’t fully appreciate his efforts until I started trying to do
something similar except simpler.
The ergonomics copy my
M5. (Fastest unfaired bike I've ever owned.) |
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The main tube is a mandrel
bent piece of 2"OD 0.055 wall muffler tubing at 8 lbs 2 oz with head
tube welded in.
The company that bent the tubing could
bend a 3” radius center-line bend, so all of the bends are that radius
to simplify their work.
The head tube is the only part welded to
the main tube; everything else clamps and so can be adjusted. (I’ve
learned that my simple computer models just aren’t good enough to cover
all of the variables.) |
| Bottom bracket clamp
is a double clamp. It adjusts front-back along the frame, and also
allows me to slide the BB shell left-right.
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Mid drive bearing
housing clamp is also a double clamp. It adjusts front-back along the
frame, and allows me to slide the bearing housing left-right. |
| Front seat mount slides
front-back along the frame. Rear seat mount is an aluminum bracket held
with hose clamps. I may move the rear of the seat down another inch. |
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Rear axle mount slides
front-back along the frame. |
| The chain idlers are also
clamps and can be adjusted. |
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The rear axle is a
1x1x36" steel with a rounded front and trailing rear welded to it. 4 lb
6 oz without wheels.
One thing I noticed during assembly (with no chains on the trike) that
you probably wouldn't with a bicycle: I had the shoes clipped into the
pedals (without my feet), and when I raised one heel and dropped it, the
shoe rocked on the crank, the crank rocked on the frame, and the trike
rocked back and forth about 1/2 inch on the floor. Low rolling
resistance; love it. When I spun both shoes, the motions become very
complex. |
Weight of 39 lbs using
the bathroom scale
((me+bike)-me) method. Not too bad for a mild steel frame tricycle.
Weight distribution with me on the bike is 55% front, 45% rear. This
will probably change when the shell is added.
After I get everything tuned in, and am happy with it, I will consider
building a lower weight frame. But I'm 20 lbs heavier than I want to be,
so hard to justify too much extra time and expense to pull 5 lbs off the
trike. |
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Handling is very quick; I tried to duplicate the front fork angle of the
Barcroft fork when used by Barcroft.
Some additional information.
- Cranks: 150mm 52/48/26. There is
some complexity to the idler system to allow the shift to the 26 and
everything to clear.
- Mid-drive: Cut down MTB crank 22/36.
It was going to be a 22/32/44, but shifting the 22/32 became a
hassle, and the 44 was higher than my knees. So it’s a 22 in, 36
out. I needed the 36 so that the chain would clear the back of the
fork.
- Final cluster: 36/11 9 spd. Overall,
23-143 gear inches. It certainly doesn’t have to be that high-geared
for me, but I want to cruise in 17 or 20 tooth final.
- 406 tires: Stelvio rear, Comet
Kevlar front.
- Front brakes only. Mechanical disc
primary, rim back-up.
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Idlers are laser-cut discs
pop-riveted together over roller blade bearings. Power side has 2
bearings, return side idlers have 1 each. |
Building a
Nosecone for Orange II
The most difficult part of
building a street fairing is finding a nosecone of the correct size for
a reasonable price. It is fairly easy to do simple curves at home, but
compound curves are more difficult. (I have been trying to talk some
college person with CFD access and time to design a 4-petal nosecone for
decades with no success.) |
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6/06/08
Finished nosecone on trike. The orange Coroplast fairing body to follow
is in the preliminary design stage. |
| Detail to show tip mechanism
for entry/egress. |
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Start with a 24” OD plastic
hemisphere from pr-tech.com. (More info on P & R Technologies at the end
of the article.) |
| Cut off the parts you don’t
want. |
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Force it into the shape you want in a mold and put it in your cardboard
oven. (Ace heat gun with circulating fan and Watlow temperature control)
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Cover the oven and heat at
200F for 1 hour. This is enough heat to allow the plastic to relax to
its forced shape.
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Recognize the error of having
your circulating fan in the output of the heat gun so the blade comes
off. Temperature was controlled to 200F at the bottom, but the top must
have gotten much hotter.
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| Redesign the mold so you can
reverse the sag. (250F for 1 hour) |
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Nosecone out of mold. I
practiced on two 20” hemispheres, and did one 24” that is good enough
for my winter work trike, and one fairly nice 24” that I’m putting on
Orange II
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| Design an attachment to the
die grinder so that you can cut 0.075” off of the trailing edge at 15
degrees. After that the trailing edge was wet-sanded with 280 grit to
break the hard edge and remove the router ripples. I plan to attach the
2mm Coroplast to the inside of the nosecone in a method
to-be-determined. Probably zip ties but possibly pop rivets. |
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P & R TECHNOLOGIES
make plastic hemispheres in a number of diameters. These are the spheres
that you see hanging on power-lines for aircraft warning, so they are
durable, and made in a number of colors. Colleen was very helpful and
friendly, and they will sell the spheres for $100/sphere (20”) and
$130/sphere (24”) plus shipping. A sphere is two hemispheres. Be certain
to specify that you do not want drainage holes, and you do not need
power-line mounting hardware.
Information at
http://www.pr-tech.com/products/markers/spanguard/spanguard-order.htm
Colleen Jackson
P & R TECHNOLOGIES
503.292.8682 phone
503.292.8697 fax
503.730.3534 mobile
colleen@prtech-pdx.com
www.pr-tech.com
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This picture triggered the
humor:
Q: "What do you do at work, Daddy?”
A: "Not much. I just sit around and bolt pieces of plastic together.”
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9/5/08
Constructing the Coroplast body.
First, I built a half-prototype out of cardboard. |
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Front view of the Orange II
velomobile with carboard fairing template. |
| Brad and his cardboard fairing
template. Then it was simply
the process of copying that pattern onto 2 sheets of 2mm Coroplast,
about a hundred zip ties, and two weeks of evenings and weekends trying
to figure out how to get in and out. |
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Length is 100 inches,
wheelbase is 42 inches, overall height is 29 inches |
| Track is 39 inches, and
nosecone width is 17 inches. |
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There is more speed hidden in
better sealing around the rear axle and in better closing of the bottom
rear. But I still need to be able to get in and out. |
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I also plan on improving the flow around
the head opening. There are some limitations in closing the hole up
as I need to be able to swing my head to use the helmet mounted
mirror, and my eye level is only 1 1/2” above the top surface.
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