Dec 18

Dec 18, 2004

Almost there!

This is pretty cool - Ben has been experimenting with some CFD (computational flow dynamics) software and has run some simulations on the Rocket with and without the disc wheels and canopy bubble. We don't know for sure how much of our total resistance is due to rolling resistance and how much is due to aerodynamic drag until I do my slow speed coast down tests, but for now, we have some other estimates including the CFD analysis. Preliminary results surprisingly show the drag being much lower than we estimated at a CdA of around .04 (sq meters). In order for the watts to match up with the speed I have been getting, if the CdA was that low, the rolling resistance would have to be super high - like around .01. If that is true, then it would be great, as it would probably be easier to fix a rolling resistance problem than an aerodynamic one. I'll have more cool CFD images later.


Whew! Man, I've been working like a dog trying to get these items done so I can do my Banff run on Monday. The weather has been warm, but FAR too windy for any kind of serious haul in the Rocket, but Mondays forecast calls for cooler temperatures which means the chinook winds will replaced with a bit of snow. A skiff of snow won't matter much and the cooler weather means no wind.

Since my last update on Tuesday, I've gotten a ton of things cleared off this list - including some addition items I hadn't planned on. Wednesday was spent working on a wheel well and head rest. The Coroplast wheel well seems to work ok, but I haven't tested it on wet roads yet. Like most things, when you change one thing, it changes something else. You can change anything, but you can never change ONE thing! I had to replace the entire steering mechanism and now the wheel well won't fit, so I'll have to modify it (I'll get into the steering fiasco later...).

Here is the finished coroplast wheel well with heat molded Sintra piece that fits into the snug area where the steering column rises up from the frame.

This is a heat molded Sintra piece that fits into the area just behind the tire where most of the water and dirt gets spun into the fairing from the wheel spinning.

This is the head rest - an aluminum bracket with a foam piece velcroed on.

On Thursday I spent the entire day experimenting with a back up steering method. This exercise in futility was initiated when I pulled back on steering bar when trying to exit the vehicle and snapped the thing in half! Since I no longer had the steering column in the way, I Though it might be a good time to experiment with some alternate method of steering if my cable system failed.

As you can see from the photos, I was trying to find a way to bring some structure into the cockpit from the rear triangle that I could grab into and steer with. Didn't work - nothing worked - waste of time.

Since the steering column was broken in half (I guess my aluminum welding isn't as good as I thought...), I decided that it might be a good time to fix a bunch of nagging issues with that whole system, so I decided to completely rebuild the whole thing and add a second set of cables for redundancy.

It all started with the removal of the old UHMW plastic bushing for the old, old, old steering column (a way back when it was underseat). That was a job!! That thing was jammed in there man.

To stiffen up that big diameter, thin walled tube (something I've been wanting to do for forever), I inserted the piece shown above and welded it in place. Then I welded on a steel rectangular tube steering column that ends with a clamp and the clamp grabs into the top part of my old aluminum steering bar.

The next thing to change was the round part the pulled the steering cables around the steering bar. The old one was aluminum and it was warping because it wasn't strong enough and didn't fit over the steerer tube well enough. I fabricated a larger diameter steel collar with some gussets to give it extra strength and help it fit better over the steerer tube.

Then I made a set of cable housing sleeves for my redundant cable set

I tossed out those ball joint rod ends that I was using in the back because they weren't really working all that well and replaced them with a double set of standard cable sleeves pointed exactly to the termination bolt.

I replaced the old steel cables with a new Kevlar set. This is the cats ass man! Totally sweet steering now - the best it's ever been. Very responsive and extremely smooth. The second set not only gives me some redundancy, it also splits the load in half. I am VERY glad I did this. Because there is so much leverage due to the way the Kevlar cable winds around the steerer tube collar, I would even suggest that might make a suitable replacement for a standard front wheel steering two wheeler lowracer streamliner where fine steering control at super fast speeds might be an advantage.

The last thing to show you, I don't really want to show you. It's a mess - well, it started out as a mess, then got even worse. I couldn't bring myself to re-do the whole thing, so I spend twice as much time simply hacking together something that works. It works, but it ain't pretty. The problem was that in order for the front derailleur to fit, I had to move the brake up, and because I didn't want to remake the whole brake hanger, I added an extension onto it - a fugly one! In the end, it would have been easier and faster to simply redesign something from scratch that would hold both the derailleur and the brake. But, this will do for now - I'll change it later.

And finally, I was doing some research and was able to locate something that will make me visible to the naked eye in day light from a more than a kilometer away! A Tektite 300 Xenon scuba strobe light! I'm not certain about the legality of using this on the road, but I'm going to cover it with an amber filter and it should end up being as bright as a car standard brake light or signal light.

The after math - a 4 day fabrication fiesta hangover.

Here is what I need to do before it's ready to go:

1. Add a fastener to the canopy bubble lid.

2. Larger vent hose

3. Visibility - Try some yellow and black safety tape on the back - or spray paint the back end red.

4. Redundant brake - This could possibly wait until after Banff. Since I only have ONE brake, I have no way to stop if it fails. Which might not be very pretty. But, the single works OK - not super great, but acceptable. Enough to slow me to a safe speed going down only one single hill on the Banff Calgary route.

5. Steering redundancy

6. Helmet - not sure what to do about this. My helmet doesn't fit in the canopy bubble. If I were to crash, the streamliner would probably slide on it's side and I would be fine - I mean, it's not like I'll be going 90 miles per hour.

7. Rear view mirror - I added a mirror today (see below for photos) and it works great. I need to better secure the rotation because it could move with heavy vibration.

8. Front wheel well - Do it - it's needed.

9. Rear wheel covers - The edges of the left inside wheel cover are not pressed against the tire - fix that.

10. Finish the strut slot sliders - This is something that I don't really need for the Banff trip. They are finished and should work OK, but I haven't tested them yet. The last time I had them installed, they were making steering an impossible job - but I have shaved down the edges and they seem to slide much easier now.

11. Re-glue Sintra Canopy lid slots.

12. Adjust the front fairing mount (causing some 'folding' between the lid and the bottom)

13. Install front derailleur

14. Add a head rest



TCR 2Do LIST:

1. Test the strut slot sliders
2. Add a rear view mirror
3. Fasten down rear of canopy bubble
4. Fasten down the Eternalight strobe with velcro
5. Look into adding MORE Eternalights
6. Re-glue Sintra canopy lid slots
7. Front wheel well
8. Add a vent hole with ducting to the canopy bubble.
9. Finish the wheel covers.
10. Add a second front caliper brake
11. Make a portable wind trainer using the (mini-rollers)
12. Look into painting the fairing
13. Find a helmet that fits in the bubble

TOTAL distance on TCR1
826 km


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