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. 🙂

Bike and Fly takeoff


Many people have asked me how I take off and land with the bicycle harness. Obviously not on wheels but on foot. Taking off in cycling mode would be impossible because the wing would knock me off immediately when I try to lift it. Landing on wheels is theoretically possible, but I never tried it. I do care about my safety, even though this project might suggest otherwise.

The trick in this entire project, why this all works is, that I simply pivot back the front part of the bicycle and my legs reach the ground comfortably without the bicycle getting in the way. So I can easily do ground handling and take off as I do with a regular harness, and land in the same way.

To show how I do it, I posted a small video of ground handling in pretty strong conditions. My wing handling is probably not the best, but the video still shows how ground handling and takeoff is possible with the bicycle.

 

Showing off takeoff skills (if any) in turbulent air

Posted by Tihamér Juhász on Tuesday, May 23, 2017

Bike and Fly at Topola

About Topola:

Topola, Bulgaria is a great site for soaring in the sea breeze. It needs winds between 12 and 25 kmh between SE and SW. The best in my opinion is 15-20 kmh South, because it gives enough lift and it is still not too strong to be able to cruise from one direction to the next. The maximum flyable coastline is approx. 13 km long when conditions are ideal.

While on holiday there, I took my flying bicycle and climbed up to the takeoff. I did not check where the official takeoff was, so I just cycled along the ridge to find a takeoff place. The track uploaded to xcontest contains both the cycling and the flying sections, because they are part of the same adventure.

Cycling on country roads in search for a suitable takeoff:

After landing:

Flying:

It was a beautiful flight so I made up plans to do a bike and fly trip covering the entire Bulgarian Black Sea coast next year.

Bike and Fly

As a long-time paraglider pilot and environmentally conscious person, I have always wondered about how green our sport is. We can fly for hours and hundreds of km without any fuel, just powered by the sun. This is the coolest thing on earth for me, but when we look at how it starts and ends, it is a completely different picture. We use airplanes, trucks, buses, cable cars and everything civilization has to offer, and which runs mostly on fossil fuel, to get to the takeoff and get back after landing. This is cheating for me, so I have been searching for greener alternatives in the last few years.

 

The most natural setup for zero-emission paragliding is using a bicycle when not flying. Sounds great, but it creates a huge amount of technical challenges: how to take a bike with you for the flight in a comfortable and safe manner; how to manage safe takeoffs and landings with a lot of metal close to your body; how to turn from biking mode to paragliding mode quickly and easily; how to carry the paragliding gear and possibly all bivouac gear on the bike; how to climb steep mountains in bike mode.

Recumbent bicycles are a great starting point to solve all these issues because they are pretty close to a paragliding harness in terms of pilot body posture. They offer a lot of opportunities in repurposing bike parts for flying. So after four years of dreaming, flying and tinkering at the workshop, I have come up with a neat solution to all the above issues: the bike rides great; I can take all my equipment and camping gear with me on land and in the air without repacking at takeoff and landing; turning the bike into a paragliding harness and back takes under a minute; it is easy and safe to take off and land on foot and it also flies pretty well; pushing the bike uphill is easier than carrying the normal paragliding backpack on my back.

What’s next? Well, flying and riding it as much as possible. And touring. With a few rules. One: every journey starts at the door of my apartment. No support car to get me anywhere. Planes, buses excluded. Getting a lift in a remote mountain region? Maybe, depending on the circumstances. As life gives it to me. But going definitely unsupported. A 4WD in the background ignored by the camera would be the most embarrassing cheat of all. So lots of rules, but they are flexible. The idea and the spirit of the journey matter most. Like the Gliderforecast Facebook page to get the news.

Python turned Peregrine

Motto and role model: E.T. The Extra-Terrestrial

In an earlier post I presented my Python bicycle. The Python was made with a very specific goal in mind: to make it fly. But first the background story. I am an avid paraglider pilot and I fly a lot of cross-country flights. Actually, the adventure I enjoy most is climb up on a hill with my almost 20 kg oversize backpack, unflold my wing, take off, climb to the nearest cloud and fly far (50-100-150 km). Covering a lot of distance and flying over fields, mountains, cities, and all this without an engine, only by figuring out where the lifting air is.

In flight my average speed is around 30 kmh, which is a very enjoyable human pace, just like when riding a bike. However, after landing, my average speed drops to a snail-like 5-6 kmh. If landing out at 15 km from the nearest road the trip takes around 3 hours carrying the same 20 kg oversize backpack. As this happened to me a few times before, it gave enough motivation and time to think about possible solutions to this issue.

The key to finding a solution was the body position when riding recumbent bikes and sitting in the paraglider harness. They are actually very similar, therefore I thought about combining a recumbent bicycle with a harness. I chose to build a Python recumbent for this purpose, because using this geometry can probably give the lightest and smallest recumbent ever. The bicycle-harness was supposed to do three things:

– work as a wheeled bag to carry/pull the 20 kg stuff up and down a mountain where there are no roads;

– work as a bicycle to cover distance to go to the take-off place, get home or at least to civilization after landing or go on a long paragliding-cycling trip;

– fly.

This is the bicycle right after finishing it:

Stainless Python.

And this is what it turned into:

In the air.
Still in the air.
Well…
Right after landing. My paraglider buddies laughed their heads off when they saw me with this thing on my back.
Trying the ride home.
Cruising by.
Take-off.
Going to the take-off place.

Well, after trying it out all I can say that it behaves very good in the air. The harness needs minor adjustments, but it works good. There was some light turbulence in the air and it behaved very much like my excellent Impress 2 pod harness, no issues with tangling or whatsoever.

To do list:

– Need to work out a proper method to fix the two bike parts together to work as a wheeled bag and during flight. Not that difficult, but need a simple and well-working solution; and thinking takes time and effort.

– Need to make a bag around the rear wheel to carry the wing, helmet and other light stuff in cycling mode. I am not good at or fond of sewing, so this will take some time.

– Using smaller wheels the Peregrine could be made even smaller and lighter. Using a different geometry would make a bicycle closer to regular bikes and easier to ride.

Until then I will just take out my Python for regular riding.

Please comment on anything you find of interest.

Python flying bike

Python recumbent bikes are like this:

or like this:

Made by Erbauer Wolfgang Schneider

They are front wheel drive and center steering recumbents invented by Jürgen Mages. On the geometry and specifications read more here: http://www.python-lowracer.de.

For me the important aspects of this bike were that it can have an extremely simple structure: just two wheels and a straight line inbetween, so it can be very light and unobtrusive. No big handlebar, double (diamond) frame, the rider is integrated with the wheels. And it can be separated/folded easily at the pivot, which is somewhere almost at the middle of the bike.

The drawbacks: you need to learn to ride it anew because it has a totally different steering mechanism than we are used to and it is reported to be unstable at speeds over 50 kmh (approx. 30 mph). These two issues though seemed worth the benefits to me. It is a special bike, probably best fit for cross-country cruising.

Learning to ride it is a joy. It takes time, but the bike is predictable and it is really refreshing to learn something this basic at this age. I do the same as my 6-year old boy, sensing and figuring it out. And progress is steady, no major setbacks or jumps in performance.

So my version of the Python was born. It has 2 20″ wheels, and is made of stainless tubing: 40×1.5 mm tube for the middle section, 25×1.5 mm for the forks (wheel cage). The pivot was trickier to make, see more below.

Stainless Python, right after the last welding.
After a few days of learning.
First wheel.

I wanted to have a hub gear and a single front sprocket. But I did not think of it, and did not know that with the fixed distance between the front and rear sprocket the chain will be inevitably loose without a chain tensioner or a mechanism to adjust the distance. The solution they used for decades: have the cut where the wheel axle fits in the frame slant and not perpendicular to the chain, so as to have enough play to adjust the wheel compared to the front sprocket. My improvisation is not really an elegant solution, but this small piece of plastic tubing did the job for now. Will do better next time.

Hind wheel

I added a telescoping seat support to adjust the seat angle. Tried to make the design clean and simple.

The back fork terminations are my favourite of all.
This is a fiberglass seat made in the UK. Check it out at oceancycle.co.uk. They deserve to get free advertisement here, so this is my vote for them.
The pivot. It is a central issue.

There was a lot of brainstorming done with this pivot. I wanted to have it strong, light and easy to take apart at the same time. I carried the parts for a while in my pocket, and showed them to anybody interested to give their ideas. But of course my trusted bike shop owner came up with the most important piece of the puzzle: the A-Head type headsets which are threadless now, they were made with threads for a short while. He gave me two of these and a discarded fork to cut off the 1 1/8″ tube and mill some threads on it.

The front (inner) part of the pivot has thus a hole in it. It is put inside the back (outer) shell of the pivot, secured with two plugs from top and bottom and a quick release rod. It actually works well, we shall see how long it lasts.

The two main parts of the pivot fit together and are secured with the thingies on the picture below.
The thingies.

I have big plans for this Python. Just need to learn to ride it well. Will show you how it works out in the next post.