[python] Re: Speculoos Recumbent HPV de Laurent Dechenne

Just noticed that I missed to answer some old postings
about Laurent's Speculoos and his latest creation.

Sorry for the delay.

On 07.11.2006 08:24, Ray Schumacher wrote:

It also seems to have significant negative trail(?)


No, the Speculoos has positive trail.

On 07.11.2006 10:02, Ghislain Pillet wrote:

About Laurent's speculoos : here is my translation of extract from a
forum (http://velorizontal.bbfr.net/ftopic306.traction-avant- directe.htm)
Question to Laurent : " about stability of forward drive recumbent bike, uphill is it difficult to hold course ... or shall I have to force on my arms to compensate the pedal induced effort..." 

Answer from Laurent "No, I climb uphill  hands in my pockets. Look at
my blog ...you've got to find the right mix between  trail and trail
angle and the angle  between pedal induced effort and steering pivot
tube and the location of the driver compared to that tube... a little tedious to explain on writing... If you keep trail angle between 55 and 60°, trail around 10 centimetres and seating as near as possible of steering pivot tube (or on), and last, seating at same height as bottom bracket... you get a stable kind of thing with interaction between the pedaling induced effort and the diretion held to a minimum so it never becomes a fuss. Voilà, you've got the whole theorical of my war treasure ..." 

Thanks for the translation Ghislain. This is a very interesting
statement from Maitre Laurent and another piece of puzzle for the
All-Embracing Generalized FWD-FWS-MBB Recumbent Bike Steering-Theory.
(short: AEG-FWD-FWS-MBB-RB-ST)


Referring to the latest creation of Laurent:

http://img91.imageshack.us/img91/558/img2734my8.jpg

On 07.11.2006 11:04, Hubert bei GMX wrote:

Und dann sieht das Ergebniss so ziemlich wie ein Airbike aus.


You are right Hubert. This is very close to the Airbike geometry.
Ziel sollte ein schneller Reisetourer auf 26 Zoll Laufrädern sein. Hubert Klapheck 

I did lots of long distance travelling with both the Airbike and
the Python. Each design has its pros and cons:

Airbike:
 + very stable at 50+ kph downhills
 - moderate traction uphills
 - unstable on loose gravel and sandy trails
 - average travelling speed around 21 kph
 + foldable
 - seat height 52 cm hurts more when falling
 - hands cannot reach ground at stops, one foot has to unclip
 - less possibilities to carry package
 - more headwind resistance
 - BB is not higher than seat
 + better overview in city traffic
 - rather uncool appearance

Python P3:
 - unstable at 50+ kph donwhills
 + good traction uphills
 + better stability on loose gravel and sandy trails
 + average travelling speed around 25 kph
 - not foldable
 + seat height 30 cm is safer when falling
 + hands reach ground when stopping, feet remain on pedals
 + carries more package
 + less headwind resistance
 + BB is higher than seat
 - less overview in city traffic
 + very cool appearance

Unnecessary to mention that the final point is the most important
one ;-)

Cheers,
Jürgen.
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