A little discussion question for the few of us that ride and post: Production motorcycles are really poor, aerodynamically speaking. I'm guessing that the people that buy motorcycles like to see the exposed mechanism of the bike (feel free to comment). But since the late 80's or so with water cooled engines, we've begun to see more enclosed engines and entire bikes such as the Goldwing and big scooters we see nowadays. So, as the tide is changing to more bodywork, what would it take for you to consider a truly aerodynamically sleek motorcycle? Craig Vetters project is sleek in concept and is proving the point that it is a practical shape for a motorcycle, but would you seriously buy it? If not, what are the defining characteristics that would make you reallly WANT an aerodynamic shape? Comfort? Wind protection? Muscularity? Illusion of speed? Classic shape from the '30's cars? Aviation classic warbird influence? Cuteness? Something else? Automotive bodies can be aerodynamic and boring (GM EV-1), and they can be aerodynamic and exciting (Fisker). True, there is only one optimally aerodynamic shape but it won't sell in numbers, some concessions have to be made to style. If you've read this far, you're interested. Please think it over. I think we are at the cusp of a time in motorcycling where aerodynamics will begin playing a larger part in the design but it's going to be tough to crack the code on what will sell. Engines are freakin' powerful these days, we could do better, but why? Suspension and handling is well understood and pretty darn good for most new bikes. As the American market buys bikes primarily as toys, styling is where it's at, and it seems there is always something strangely new each year by somebody. What aerodynamic shape or theme would cause a positive emotional respose in you? I like landspeed racers, and drag bikes, and the DG Alligator. Low and sleek. Oh yeah, formed aluminum panels and rivets are retro-cool also. The dustbin fairings are cool but only if they look really old.
I know that bike aero is bad, but I think that most of the losses are pumping losses from throttling massive engines. 1.8 liter for a bike is nuts. (IMO) My FIT get better MPGs than most sports bikes. Heck, the Yamaha VMAX barely get 25 MPG.
Gearing has a big factor. Manufacturers gear low so that top gear freeway roll-on performance matches the intent of the bike. This usually results in gearing way, way too low for decent FE. With stratospheric redlines for big motors like the 'Busa, 197 mph is reached with a gear left to go. Throttling losses are a factor, but 250cc engines running 80%-100% open on the freeway still only return like 60 mpg, not much throttle loss there. Must be something else. My 1000cc bike has tons of throttling loss and gets about 54 combined. Lower with only freeway.
Yeah, about 400-500cc is really plenty for anyone to get anywhere they need to go with long term durability. A well built and maintained 250 will last a fairly long time. Ninja 250 engines are usually done at about 70 or 80 thousand miles, less if broken in and maintained poorly. To try to steer this back, the question here though is that aerodynamics plays a really big part of motorcycle fuel consumption at freeway speeds. What would it take for you to be motivated to buy an aerodynamically sleek bike? Landspeed racers are really sleek, but uncomfortable and not practical. Vetter MPG competitors, very slightly more comfortable, looked pretty wierd in the day, but don't look so bad since bodywork is now more common. Top fuel drag bikes are better than stockers but are still recognizable for their intended roots. Electric bikes are totally new and mimic the aerodynamically poor gas powered cousins (a chance to change things if ever there was one). The Hyabusa and ZX12 are pretty good as a stocker as thats how they can manage just shy of 200mph with the rider in a full tuck. Gee, are aerodynamically sleek motorcyles only for us geeks that want a fast comfortable freeway bike with a modest motor with 80+ mpg at freeway speeds? It just seems that improving the designs of the bodywork we're now used to, to be at least good, not optimal, motorcycle aero will produce many benefits. Benefits like rider protection from elements, even crash protection, improved freeway power, and fuel mileage seem like just what at least some of the consumers are looking for. So, any ideas?
I actually really like the EcoMobile... and would like it even better with an electric drivetrain. Reasonably aerodynamic, enclosed from the elements, capable of low speed maneuvering without tipping while keep your feet inside. With studded tires it might even handle snow/ice conditions reasonably? Too bad they are so expensive. I suspect they could get away with a lot lower displacement engine than the ones I've seen advertised (1000 to 1200).
I see the main problem in the rider position. Although on my commutes (~25km / 15 miles) I usually take that tuck position to prolong my glides after pulses (and only for the glides, Teresa with those wide, straight handlebars is totally unfit for it so I'm not in the same control as normally) but I couldn't do it during a longer ride, like the one we had lately (~500km from Vértesacsa, Hungary to Bled, Slovenia). So, to put it bluntly, you can have aerodynamics OR range, but not both. Craig Vetters vehicles look very interesting and I can't deny their efficiency, but I can't imagine how would it feel to ride(?) them. Those are... I don't know what they are, but not motorcycles anymore. I don't even know how I could stop with them at a traffic light, or how I could push them if needed. What control I'd get at all? (It would be fun to try one anyway, I'd get the answers too...) What I'd like to see is something in-between. A motorcycle that's efficiently shaped and - if it's possible at all - somehow cares about aero drag aroud the rider who sits comfortable and is in control and is still "outside". I'd even try to do minor mods - if they measurably help yet don't clash with the original design too much
With >100,000 miles on motorcycles, I think a streamlined 250 would be the way to go. Streamlining would give it top speed performance far above the typical 75 mph top speed for the class, and give the bike some respectability. No one would expect it, therefore it might just work. Once you get into 600 cc and up, those bikes have enough power to push through the wind, and there's some satisfaction in doing just that. Under 250 cc, many bikes aren't highway-legal. limiting their usefulness.
Alvaro84, I think you're right that many people want to feel like they are outside yet still have wind protection and good aerodynamics would be a benefit. Reasonable comfort is a must, especially for us older (er, experienced) riders. SentraSE-R, 250cc seems to be the lowest practical limit really. These have to run pretty hard to blend with traffic making break-in a fragile balance of staying up with traffic and not shortening the life of the motor. Maybe the manufacturers will figure a solution out though. Also you mentioned the satisfaction of pushing through the wind. Yeah, sometimes the experience of being in the wind is a large part of the appeal. One of the bikes that I thought might be a step in the right direction was the Honda DN-01, sleek kind of aero styling, comfortable position, long wheelbase, low seat height. But sometimes Honda models comeout ten years before the public is ready for them, maybe this is the case again here. For this discussion, the motor is too big and it's not aero enough. Maybe what is wanted is more of an F-1 influence. A very elemental design with exposed wheels and maybe some other mechanical parts with careful attention to detail to aero with strategically placed scoops, diffusers, vortex generators, etc to help clean up the airflow. The key to the whole thing, and tricky part, is that it's easy to make the bike sleek but everything changes when the rider sits on it and completely destroys the sleekness. The most appropriate example of a motorcycle that truly integrates the rider in a relatively comfortable position is the Dan Gurney Alligator http://www.allamericanracers.com/alligator/alligator_home.html. Here the bike looks kind of silly until the rider sits on it, then it all suddenly makes sense. Maybe if F-1 aerodynamic philosophy was applied here more fully it would be the first concrete step toward a marketable aerodynamic bike?
