Quote:
Originally Posted by samwichse
Something like this?
https://kronfeldmotors.com/specs/
Although it's a series hybrid, your pedaling just goes to charging the battery and there's no direct connection to the wheels. |
Sort of. The difference between that and what I want to build is the following:
1) The linked vehicle has far too high of a frontal area and given its specs it's overall aerodynamics aren't on par with those typical of a commercial velomobile. I seek to build something with the form factor and drag of a velomobile. This is built to offer a large rider plenty of room and a tall ride height, whereas I'd build a low-slung vehicle to fit the rider like a glove.
2) The linked vehicle is extremely heavy. It is built closer to the safety specs of a car than those of a velomobile. Because of its oversized motor and battery pack, it requires more pounds of battery per mile of range. To me, this is greatly extraneous. Lightness and efficiency beget more lightness and efficiency, and this thing is built to be so heavy that its components all must be heavier to compensate for it. This thing is as heavy as a high performance motorcycle, if not moreso.
3) If the battery runs out of charge or the EV drive system fails, the above vehicle is stranded. I intend to make a vehicle that can still function as a bicycle and be independent of the need for an EV drive system to move, which will require keeping it sufficiently low in mass that a fit rider can still pedal it up a steep hill and sufficiently low in drag that on flat ground and downhill it yields a significant advantage over a normal upright bicycle.
This all said, the Raht Racer is an interesting and cool concept. But the pedal generator isn't going to contribute much to its total energy use, probably on the order of a percentage point or two. It is reminiscent of the Twike designs in that sense. It's much too bloated for the application I have in mind, and the pedal drive system seems to be a gimmick from a purely functional standpoint, if the function is reducing electricity usage.
What I want to do is make a vehicle that can perform like a car, but still function purely as a bicycle whenever the need arises. This in turn will assure that it reaps the benefits that come with that, such as phenomenal energy efficiency. With the design I have in mind, it is conceivable that even careening down a highway at 100 mph, a fit cyclist could still conceivably account for 10% or more of the load for a few minutes at a time, and at freeway speeds of 60-70 mph, maybe even 20% of the load for hours at a time, or turn the motor off entirely and account for 100% of the load riding it at 25-30 mph in the city. The 450 city/230 hwy MPGe of the Raht Racer could EASILY be beaten by a wide margin. Mine gets between 3,000-4,000 MPGe as it is, even though unlike the Raht Racer it has zero crashworthiness nor is it nearly as fast, but I intend to improve upon that. There are electrified Milan SL velomobiles getting 5,000+ MPGe in city riding and if made mechanically reliable and dynamically stable for high speed riding, with their aerodynamics could easily get 2,000+ MPGe highway, and like most commercial velomobiles, they have some rudimentary degree of crash-worthiness designed into them. A modern velomobile is not anything close to as safe as a modern car, but it's greatly safer than a bicycle or motorcycle, and I think that is a reasonable degree of safety to design for when coupled with robust enough wheels/tires/axles/hubs/brakes/chassis to handle 70 mph freeway cruising, and all of which is possible within the maximum weight limit I have in mind of 100 lbs.