Nov 26

Nov 26, 2004

Slow going...

Sorry about the delay in getting a status report out. I've been working, but on a bunch of different things at once and they are all taking a really long time. I didn't want to post anything until I had something complete to show.

I've been working on a way to enclose the rear strut slots. I tried every kind of flexible baffle I could think of but nothing worked including neoprene, spandex, rubber garage door seal, rubber base board and a few other soft rubbery strips that I found. I finally ended up making a sliding door out of sintra and a piece of rubber base board - a lot of intricate work! It seems to work fine but it's not quite finished yet - a fairly smooth sliding action and the rubber slider is very tight to the fairing for a good aerodynamic transition.

One thing I have been paying some attention to with the sliders is if anything got stuck in there the steering might seize up and that could be very bad. So, I am making sure than any part that moves can be crushed with steering force in case something sticks. That's why I'm using soft rubber for the sliding door.

The fairing now stays on without tape. I added two bungie straps to the lid, and two thumb screw knobs to each side. For a watts test, I would probably add tape anyhow to smoothen out the seam, but for everyday riding, its now a lot easier to take the lid off and put it back on again - plus I'm not constantly using up rolls of expensive duct tape.

I made some Sintra plastic disc wheels for both of the rear wheels. It looks like they're going to work out very well and they look pretty slick. The plastic disc rides right up onto the sidewall of the tire making a smooth aero transition from the round tire to the wheel disc.

I also removed the heavy and draggy rear disc brakes and fabricated a front wheel caliper brake instead. I haven't had a chance to test this out, so I'm not sure how it will compare with the two disc brakes. Since about 50% of my weight is on the front wheel, I would expect that a single front brake would work as well as both rears, but it's not a disc brake so we'll see.

I've ordered a canopy bubble from a few different sources in the hope that one of them works out. The plan is to stack 1/4" styrofoam shapes and sand it down (like I did for the main fairing) for the bubble top tail fairing. I'll sculpt the foam when I have the Lexan dome to shape it around. Then I'll wax it, spray it with mold release and put a few layers of fiberglass on.

I got a great email from John Snyder the other day who was reading through my watts test reports. He suggested that I input all the combinations of data pairs into his spread sheet and then average out the results. He did that for me and ended up with:

CdA of .11 sq meters which converts to a CdA of 1.18 and a rolling resistance of .0060.

If a CdA of 1.18 is correct, here is how TCR2 compares to other human powered vehicles:

HPV Image Name CdA sq meters CdA sq feet Speed @150 watt output
Barracuda 0.055 .592 44.4 kph
Gold Rush 0.0465 .50 46 kph
White Hawk 0.031 .324 50.7 kph
Bean II 0.0289 .301 51.5 kph
Cutting Edge 0.0286 .307 51.2 kph
Cheetah 0.0278 .299 51.5 kph
M5 #8 fairing 0.0255 .274 52.3 kph
Varna Diablo 0.02 .215 55 kph
Virtual Edge 0.011 .118 60.8 kph
DF Standard bike 0.68 7.3 22.6 kph
DF Mountain bike 0.50 5.38 24.7 kph
DF Racing bike (hands on top of bars) 0.51 5.4 24.7 kph
DF Racing bike (using aerobars & disk wheels) 0.23 2.4 31 kph
Easy Racer (no fairing) 0.27 2.9 29.4 kph
Quest velomobile 1.2 37.7 kph
John Tetz - Zote Streamliner .055 .6 44.2 kph
Sonny Kallehave - High racer .3 3.22 28.6
Jørgen Høiberg - Leitra velomobile .178 1.91 33 kph
Mark Olaf Slot - Optima Baron .147 1.58 34.7 kph
TCR2 .11 1.18 37.5 kph
Vector Trike .046 .5 46 kph

All Cr (rolling resistance) set to .0060
Temp = 21 degrees C
Pressure = 30 " mercury
weight = 230 lbs including rider

John Tetz has been after me to do some proper coast down tests to determine once and for all, exactly where the CdA and Crr are. I'll get to that as soon as I finish my work and the weather cooperates.


TCR2 (track) 2Do LIST:

1. Make a platform for the wind trainer (mini-rollers)
2. Add front caliper brake
3. Mount first fairing and all the work required with that
4. Make front wheel fairing
5. Make rear wheel discs
6. Make a new steering bar that rises up a bit higher - also takes up less room on the sides so fairing can be tighter
7. Adjustable seat height
8. Make fiberglass canopy top with acrylic bubble and tailbox
9. Paint this puppy!
10. Rear strut supports
11. lower and chop
12. Make sliders for the rear struts


TCR1 (cross country) 2Do LIST:

1 Add front derailleur
2 Run road, roll-over and watts tests for new suspension system
3 Worm gear steer prototype (Waiting for final design and parts list from Ben)

TOTAL distance on TCR1
826 km


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