Torben

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A Danish Python

The Python is a front wheel drive, center-steered low rider/racer. The idea comes from Jürgen Mages in Germany - it is build upon ideas from Airbike and Flevobike. To combine FWD with lowracer and center-steering is remarkable in itself, another remarkable thing is that the project is developing from prototype in a kind of "Open Source" environment. Experiences and ideas is shared on a mail list, and the enthusiasm from the few participants is big. The construction in itself is a stroke of genius in my opinion - that is, if one can learn to ride it..

jurgen.jpg
Jürgen
fall.jpg
fall

The number of people who can ride it can be counted on one hand to my knowledge (summer '04). Perhaps Jürgen is the only one who takes it on prolonged trips, but the number of pilots around the world is rising, judging from posts on the mail list and pictures on the website. That is a challenge I can understand, so I took on my thinking hat and started wondering if I could tweak the design to make my own sub-species of the Python. A prototype should not be copied, but improved. I hope I'm able to not destroy the design with my "improvements" :-)


My version is not as recycle oriented as Jürgen's, the major differences are :

  My solution Prototype P1 & P3
Seat a home made aluminum hard shell seat - later a carbon hard shell seat. a flexible seat made from plywood, safety belts, a front fork, some metal tubing and foam
Pivot axle, bearings, steering damper and housing from Tempelmann (Flevobike) ~80euro standard bottom bracket and crank arms
Rear fork made from 30*10*1,5 square tubing - no suspension a suspended front fork
Welding/brazing brazing welding

Well, the easy part is almost over - the building process. Now I'm looking forward to ride it. A couple of pictures:

garage_small.jpg
Garage
sleek_small.jpg
Sleek!
sideview_small.jpg
Sideview w. nice carbon
done_small.jpg
Ready for testrides w. aluseat

Training diary

June 14. Building almost finished - ready for test rides. Distance
June 15. Bragging day - showing the bike off to a HPV-friend - approx. 15 minutes of practice - no control at all, some lucky shots of keeping it upright for a few meters. 100m
Pic's </tr> getagrip_small.jpgtakeoff_small.jpgbye_small.jpgAAAARGH_small.jpg
100m
June 16 45minutes of practice - after some wobbling and a few falls it started to improve - I had several rides for 40 meters and the last one was 75, without touching the ground. I have no real control over turns, but I can make small corrections which sometimes work as intended ;-) The "gut feeling" says that I'm going to learn this, and the design seems to work. I was giggling all the time, feeling like a child (and probably looking like one :-). One of the fingers of my garden gloves is worn through - stage tape to the rescue! 

Tricks (that works for me) and theories :

  • It seems like it's easier to ride slight uphill when learning, opposite other recumbents. Maybe because I haven't got a brake yet ;-)
  • The foot-steering works best (fastest) in LOW gear, as corrections can be made on each pedal stroke. Spin spin spin.
  • Lean back and try not to focus on the front frame - it's very important to maintain contact with the seat.
  • If you have the courage, try to ride with your eyes closed for a bit when you have a bit of control - I think it can help the body to learn the technique.
1km
June 22. No training due to a busy week and a bad back (I don't know if the Python training started this, but it may be good advice to warm up, and have regular breaks during training). I think I'll be ready to continue in a few days. 1km
June 28. 60 minutes of training - there's progress! I had several runs up to 150 meter, and I'm beginning to miss a brake seriously. On slight downhill's, the bike rolls waay too fast, and as the anxiety kicks in, I'm having trouble with the balance ;-) 
I tried to ride on a large field of grass (the playground at my daughters school), and it works like a charm when the first balance issues is solved. It gives resistance to the bike, so some force is needed to keep the speed - it seems to help the steering. The roughness was not a big problem. I even rode in big circles in the end, and had some semi-successful turns. Look into the turn and feel that seat against your back.
5km
July 23. Oh My Gosh! Has it been so long.. 2 hours of training today revealed that I haven't forgot everything. I rode at the local stadium (at the rubber running tracks) and got a max. distance of about 4km. I guess I rode about 10km in total at the speed of around 16km/h. Before the second hour of training, I removed the steering damper - the bike gets more lively, but the greater freedom at the link helps when I'm about to loose control.

I have reinforced the frame several places, and mounted a front brake and a gear shifter. The rear frame bend was the first weak spot, it started to stretch at the bottom of the tube, forcing the vertical bracings apart. I have cut out 1.5mm plate and brazed it to the sides of the square tube. The front frame got 5 plates (one for each bend) and a complicated "reinforcement box" for the bottom bracket.</td>

15km</td>
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August 2.</td> Went for a 8 km ride on bike paths - mostly stone on tar surface and some gravel and mud. Took a spill in the mud - was going downhill too fast (20km/t) and the frontwheel slipped in the mud. Must have been a sight - Me stomach up on hands and feet's, and the bike casually on the side below me. The handling isn't good enough for roads yet, but I'm getting more confident. I believe that the seat should be glued to the upper back, it is SOO important to keep contact with it. 
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23km</td>
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August 3.</td> Same ride as yesterday, but I went a little further. Rode with clipless - and apparently I was ready for it. I didn't fall, but had to walk up some short steep hills.</span><p> After the ride I mounted handlebars, I'll post pictures when I find the time. A short ride to the stadium and a few rounds on the tracks felt really good and I had the most confident feeling yet. I think it's best to learn the foot-steering first, and then start to use the handlebars. It's very easy to forget what the main steering extremities are when the handlebars are there. On the Python the handlebars are just for fine-tuning and problem situations (and for brake levers and shifters). When turning they help a lot - I was riding at some speed (~25km/h) at the tracks  without gloves yay!.</td> 38km</td>
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August 8.</td> I had a visit today - Rasmus and his friend came to have a look prior to their own build. I demonstrated that the thing really is  rideable - I think it's easy to think of the whole project as some kind of Internet scam ;-) I'm proud to be able to guide newbee's in the right direction :-)<p>The handlebars works great! I made a 24km roundtrip in the beautiful sunset. I had one spill when I went under a bar at 1 km/h :-)

No gloves, clipless pedals, speeds up to 30 km/h. It's not easy to let go of the bars when I'm moving at speed,  but I'm practicing :-)</p>

     <p>One tip : at low speed, It's possible to accelerate out of problems (i.e. leaning too far in a turn). The front of the bike just drags the rest with it and gains steering speed.
62km</td>
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August 9.</td> 32km - narrow tires are not good with gravel forest roads. I dropped the bike several times, so now I need to redo the handlebar mount. Some of the trip was on public roads, but I didn't feel safe at all. The bike is great on smooth asphalt, though.</td> 94km</td>
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October 26.</td> Seat and handlebar mount fixed some time ago. Brazed Front Derailleur mount and rear brake mount last night - haven't had time for any riding lately :-(  I need to make a clever (light, and no-tool-dismantle)seatmount.</td> 94km</td>
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November 1.</td> Rear seat mount brazed - front still temporary. Went for a small ride in the dark - skil not completely forgotten ;-) Hey! If i braze a tube for the front mount, I'm (almost) ready for paint! </td> 97km</td>
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November 4.</td> Front seat mount brazed and mounted. What remains before paint :
  • rear to front frame mounting needs enforcement
  • closure of frameopenings
  • 1-2 cableguides
  • enforcement of front derailler tube (for peace of mind)
  • finishing seatmounts for quick assembly and disassembly.
   Not quite there yet I guess..</td>
97km</td>
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April 2005</td> A nice ride on bikepaths in a former military area, now recreational area. Not very confident.</td> 118km</td>
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June 2005</td> Most of the planned frame improvements is made - I need to make support tubes for the seat. I rode to Leitra and back on public roads - no spills, and I got a lot more confident. Coasting is still max. 30km/h - stability is getting better when i push slightly on the pedals with both feets. </td> 160km</td>
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October 2005</td> Paint applied, new handlebars mounted - a big improvement. I'm dreaming of long rides now.</td> 165km</td>
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Pic's 'n vid's</td> python_lak1_small.jpg python_lak2_small.jpg python_lak3_small.jpg</td>  </td>
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 </td> Video of Python Ride

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