Bike and Fly Version 3

It’s been a while since I built a flying bike or any recumbent. My friend Cody Richardson contacted me a while ago so that I build him one, so I pulled myself together and built a new iteration of the flying bike, the V3. Thank you Cody, for the energy, inspiration and confidence you gave to this project. You will get your bike. This is a Python recumbent like the V1, but with a twist.

My goals with the V3 flying bike were good rideability, extreme simplicity, low weight, and compactness in flight. The current design is a very good tradeoff to meet these goals. In the picture below the bike has an experimental pivot to find the best pivot angle for riding (will be replaced soon). The folding mechanism will be installed in the geometric middle of the bike under my butt. The front wheel has a monocycle direct drive hub. I will replace this simple hub with a geared hub when I can put my hands on one. The geared hub will come from Kervelo or MC2 Bike. I really hope that one of them will sell me a hub.

V3 prototype (testing pivot, monocycle hub and no folding mechanism).

The testing pivot was installed to find the best pivot angle. This is a Python recumbent with a negative trail and 60-65° pivot angle. A regular Python does not have direct drive hub, so this should be somewhat different in handling. I therefore wanted to find out the best pivot angle for it. I designed a pivot with an adjustable angle for testing.

The starting angle was 60°, and I was able to adjust it to +/- 6 degrees. This was perfect for testing. My tests are based on starting from 60° and going down to 56° and up to 66° Here are my findings:

  • 60°: It is pretty rideable, somewhat light and wobbly.
  • 58°: Even more light and wobbly, but rideable. Actually fun.
  • 56°: Still rideable, but too wobbly. Not fun anymore.

It didn’t make sense to have an even shallower angle, it would have been pretty much unrideable at 55° or less.

  • 62°: pretty good, less light and wobbly than at 60°
  • 63°: pretty good, but it actually felt more jerky than at 62° (It may be just an impression, 62° and 63° were very close.)
  • 64°: sooo good and smooth
  • 65°: still nice, but not so good as 64°
  • 66°: feels heavy to flop on one side or the other, barely rideable

At the end I set the pivot at 64° and it was just perfect.

Riding experience at 64°: I didn’t feel any pedal steering interference. The bike just felt right. Event at 60°, I sat down on it and went on a 100m ride from the start. I had a cornering radius of around double that of a regular MTB. This will get better in time for sure, but V3 will never have the steering agility of a good MTB. This bike is meant for going straight and in comfort for long distances.

I didn’t test its climbing performance, but I expect it to be pretty weak. Climbing was a tradeoff that I sacrificed in this design. The bike has a 45% to 65% weight distribution approximately. The driven front wheel has already 45% of the weight on it, and this gets even less on an upward slope. Will see how it works, but this bike is meant to climb in thermals not on slopes.

This was my adjustment stand. It was very basic, but it worked pretty good.

The pivot under adjustment:

I hesitated to publish these images, because they show a work-in-progress prototype, with unfinished tack welds and all the unfinished ugly details. Trust me, the bike will look smooth and awesome at the end and it will bike and fly well. 🙂