Jan 13, 2005

A few thoughts on the Trans Canada objective

I have travelled over 800 km on the lean steer trike, and a couple hundred in the fully faired Rocket – most of those miles on the highway so I have a much better idea of exactly what it’s like – the pros and cons of spending some serious time in a fully faired velomobile on the highway with other vehicles and mother nature. I have a much better feel for the kind of vehicle that is required to successfully cross this large continent. To be brutally honest, I’m not sure the Rocket in it’s current state is the best choice.

Highway shoulder width: Parts of the trans Canada highway has a fairly large shoulder, but parts of it has almost no shoulder at all. Combine no shoulder with a single lane (I know – it’s lame, but this is Canada, not New Jersey) and you have safety issues with the vehicular traffic you share the lane with. Add to that, the fact that the Rocket is over 34″ wide, and you double the risk of getting clipped by a fast moving vehicle who didn’t see you until the last minute. The solution to dealing with narrow or non existent shoulders is a two wheeled recumbent that is the same width as a road bike or touring bike. Hundreds of those transit the country every year without incident.

Rumble strips: When you combine a narrow shoulder with rumble strips and a 34″ wide trike, you stand a very good chance of the left rear trike wheel riding over the grooves. That’s not acceptable. Even with wide shoulders, repeated accidental wonderings over to the rumble strip will eventually shake the trike apart, not to mention the pilot. Narrow shoulders guarantee that the left rear wheel will be permanently jack hammered. Again, the solution to the rumble strip problem is to go with a two wheeled vehicle.

Wind: When the wind is blowing hard (about 50% of the time here in Southern Alberta), controlling the streamliner is very difficult and a lot of work. It’s also potentially dangerous, as a wind gust has the potential to blow you into traffic. The type of vehicle ideally suited to a cross country would be something that is easily converted to something with less fairing surface area for the wind to blow against. I’m not sure what this might be – perhaps a bike with a partial fairing rather than fully enclosed. Another potential solution to side wind is a fairing that is much wider than a typical streamliner – something more like a solar car (The X of 1 solar car is being built by a fellow Canadian to set a world solar car distance record). The problem with a wide fairing like that, is it would no longer fit into a typical shoulder.

Heat: It gets very hot inside that fully enclosed fairing – even on a relatively cold day, I could be sweating like a dog in there. I’m not sure exactly how comfortable that would be hour after hour, day after day on a long cross country trek. I would suggest again, that perhaps something with a partial fairing might be more suitable – or at least a fully faired vehicle with a large removeable top.

Efficiency: In order to beat the existing cross Canada record, it was my intention to take advantage of science and technology to design a more aerodynamic vehicle. The Rocket definitely is that – with a current CdA of 1.1 compared to about 5 for a road bike, it’s far more efficient than a typical road bike, but nowhere near as efficient as other streamliners. In fact, it’s only slightly more efficient than an unfaired lowracer with a tail box.

Speed stability: I am still somewhat concerned about high speed stability of the lean steer configuration. Without the fairing and without the heavy stabilizing weight of the fairing, it’s a bit strange at very, very high speeds over sudden bumps. This is probably due to the bump steer phenomenon and according to Bob Rohorn, it’s just something to get used to and probably won’t cause a crash. The other concern is high speed cornering stability due to the trike wheels – any trike geometry has the same issues with super high speed cornering and that is tipping. The Rocket is as stable or more stable than most commercial trikes, but none of them are anywhere near as stable as a two wheeled lowracer.

Weight: Canada isn’t flat. Weight is the biggest issue when climbing mountains or hills, and currently the Rocket weighs in at over 75 pounds! I compare that to John Tetz’s fully faired Zote foam streamliner which weighs about 30 pounds and has a CdA of .6 compared to my 1.1. To put that into perspective for you, here is a speed comparison of our respective vehicles at 150 watts of input power climbing various grades:

Being visible: I learned this from flight training: when something is nearly invisible to the wind, it’s also nearly invisible to the eye. When you are flying a small plane, spotting other planes near you in the circuit is very important and sometimes very difficult to do. It’s the same phenomenon with fairings – cars approaching from behind can’t see you. Less streamlining definitely helps here – a standard recumbent bike is far more noticeable. I believe this issue can be solved with lighting – flashing lights with enough luminosity to be seen during the day from miles away – like a standard brake or signal lamp on the car.

Turning radius: Currently, the turning radius on the Rocket sucks. It’s more than enough for general highway travel, but not nearly enough for convenient use around a city.

THE IDEAL CROSS COUNTRY RECORD SETTING VEHICLE

Don’t get me wrong – I LOVE the lean steer trike. Absolutely love it. It’s a blast to ride, handles great and is very stable and comfortable. It benefits from very efficient power transfer to the front drive wheel due to the fixed front wheel and short chain, and is fairly aerodynamically efficient as far as commercial velomobiles go – even with the two rear trike wheels sticking out of the fairing in the back. I believe it would make a pretty good daily use velomobile – but perhaps not a record breaking speed bike, or a suitable cross country HPV.

Here is a list of what I think the ideal cross country speed record setting human powered vehicle should be:

1. 40 pounds maximum weight. There are plenty of hills and mountains and the lighter the better. Ideally, I would love for this vehicle to weigh no more than 30 pounds.

2. It should have two wheels to fit into narrow shoulders and between the rumble strips and the edge of the road. Also two wheels solve the high speed stability issues. Incidentally, I am aware of a couple who travelled across Austrailia in two custom fully faired trikes. When Stuart Andrews and Paula Mathews were asked what they would change if they had to do it again, then both admitted that they would rather do it in a two wheeled recumbent than a trike for all the same reasons I have just given.

3. It could have a three wheel option for comfort when required and stability while climbing steep hills and/or negotiating around tight corners through cities and towns.

4. It should feature some suspension to avoid rider fatigue and discomfort

5. It should feature an adjustable seat (seat bottom up and down, and seat top back and fourth) to change the seat angle for variety in muscle recruitment.

6. It should feature a minimum of side fairing profile to avoid control issues in cross winds – either that or an airfoil profile from the side that helps direct cross winds over and around the vehicle.

7. The fairing should feature plenty of easily removable surface areas to aid in rider cooling when and if conditions allow.

8. It should be very aerodynamically efficient – ideally a CdA of .6 or better.

9. It should feature highly luminous lighting at the rear for visibility in traffic.

Possible candidates:

1. Low racer with a tail box.

(This is Jim Scozzava’s Optima Baron with carbon tailbox – I hope he doesn’t mind me using his photo)

A good carbon low racer with a tail fairing would weigh no more than 30 pounds – in fact, I know of some that weigh-in at around 20! They are very stable at high speeds, feature a minimum of fairing area to aid in cooling and avoidance of wind turbulence and are narrow enough to fit into shoulders of any width. Typically, commercially available lowracers do not feature adjustable seats, but a custom model very easily could. The draw-back to a tail boxed lowracer is less aerodynamic efficiency than a fully faired vehicle. The CdA of a good lowracer with a tailbox is around 1.58. That equates to about 37 kph at 150 watts on flat ground which incidentally is 1 kph slower than the fully faired Rocket.

2. Lighting recumbent with body sock.

This was the vehicle of choice for the 2004 Race Across America HPV team and the current record holder for a human powered cross America team effort (5 days, 1 hour!!!!). If it was good enough for two trans America records, then perhaps it’s good enough for a cross Canada record. These bikes are very comfortable, feature a removable soft spandex fairing cover, and weigh in at less than 30 pounds. I would suggest the only draw back is less aerodynamic efficiency (can’t find any references to the actual CdA value) than a full fairing and that I personally think they look funny.

3. Zote foam streamliner

This is John Tetz’s semi-hard shell Zote foam streamliner. It weighs only 33 pounds and features an AWESOME CdA of .6 which equates to 46 kph at 150 watts!!!). It could also feature more removable fairing sections for rider cooling, and wind gust avoidance.

4. Custom carbon faired streamliner

This is a rough concept that takes advantage of the best of all the possible vehicle candidates and incorporates as many of my prerequisites as possible.

A FWD two wheeled lowracer – possibly made from Zote foam to keep it light.

Removable top to simulate a lowracer with a tailbox, but with a nose cone also. There is still plenty of fairing surface area for the wind to blow around, so perhaps the nose cone could be removable also.

The vehicle could feature retractable trike wheels for slow speed manouvering, hill climbing or parking. These rear wheels could be very small because rolling resistance isn’t as much of a concern for manouvering speeds.

This shows a couple of options as to how the removable top could be stowed. Another option could be a soft removable top made from Spandex like the body sock, or a plastic like Zote foam or lexan that could be rolled up.

For now, I am going to continue to work away at the Rocket with the goal of making it a good, solid velomobile to gain yet more experience with velomobile travel around town and on the highway. That experience so far as been invaluable, and perhaps over time will gain me more insight into exactly the kind of vehicle that is required for a trans Canada speed record.

TCR Do LIST:

1. Strut slot sliders – Simplify to a folding cover
2. Canopy Bubble – make a sliding convertible top
3. Front wheel well – Make glass version
4. Wingnuts for fairing mounts
5. Electrical – rechargable battery with a panel with switches for rear strobe and front headlight
6 Add a second front caliper brake
7. Make a portable wind trainer using the (mini-rollers)
8. Look into painting the fairing
9. Find a helmet that fits in the bubble
10. Add second brake

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