[python] Re: Why a Tadpole?
- From: Patrick van Gompel <patrick_van_gompel@xxxxxxxxxxx>
- To: <python@xxxxxxxxxxxxx>
- Date: Sun, 4 Sep 2011 20:33:31 +0200
Interesting discussion.
Probably you guys know, but I found this document very usefull for trike setup
comparisons, steering angles and other stuff:
http://www.hellbentcycles.com/trike_projects/Recumbent%20Trike%20Design%20Primer.pdf
I was wondering this statement too: "With 2 front wheels
driving/steering/braking, we should get more traction/control/stopping power."
-Not sure why 2 front wheels give better control. If you have all the right
angles for both wheels it might, but if you have not, it probably makes things
worse.
-Nowadays any decent brake has more than enough power to stop the wheel. So
having two front brakes instead of one wouldn't make much difference. What does
matter is where you CoG is positioned. Usually it is easier to flip over the
two front wheels of a tadpole than over the one more foward placed front wheel
of a delta. And, having one front brake is less complicated than having two. A
lot of tadpoles seem to suffer from 'brake turning' (or what is the proper
word?).
Gerald, there is another thing to consider (your last point). Although your
legs bent to the inside of the bent, your front wheel contact point goes to the
inside as well. So your CoG might actually move to the outside of the bent. Of
course that depends on the construction of your bike and the rider.
Patrick
From: bepb@xxxxxx
To: python@xxxxxxxxxxxxx
Date: Sun, 4 Sep 2011 19:48:40 +0200
Subject: [python] AW: Re: Why a Tadpole?
Hi Vi,
there is a strong point in the curiosity, no question. Its been the reason I
have been thinking about a tadpole python myself.
The shell for the delta somehow need to adapt to the bending off the trike, but
in which way could a tadpole python solve this issue?
Concerning driving I dont see where the FWD tadpole has an inherent advantage.
The additional contact area will be nullified by the less load per area for
breaking and driving.
I like the considerations about the placement off the solar pannel. In my case,
I should place the panel on the back. I generaly drive in westery directions in
the morning and easterly coming home from work in the evening.
There are some sources comparing tadpole vs delta on the net, but they seem to
have in common that they focus on LWB deltas vs SWB tadpoles.
But there are some huge differences between a python delta and a LWB delta.
*On python trikes, the load is significant more on the front wheel. You need
this to avoid wheel slip.
*I dont think that there is need to have the CoG (Center of Gravity) any higher
than with a tadpole.
*On the python trike, the frontwheel actually tilts because off the pivot angle
0~50*.
*Since the steering involves moving the legs to the inside off the bent, weight
distribution should improve, certainly over the LWB delta, most propbly also
over the tadpole.
Maybe we need a python trike based comparison?
Gerald
-----Ursprüngliche Nachricht-----
Von: Vi Vuong <vi_vuong@xxxxxxxxx>
An: "python@xxxxxxxxxxxxx" <python@xxxxxxxxxxxxx>
Gesendet: So., 04. Sep 2011, 06:13:58 GMT+00:00
Betreff: [python] Re: Why a Tadpole?
Hi Gerald,
With 2 front wheels driving/steering/braking, we should get more
traction/control/stopping power. Tadpole also fits nicely in a standard
streamlined shell, http://www.youtube.com/watch?v=jETRur5Bf58, but it should be
possible to achieve similar
level of aerodynamics with advanced shell design for a delta...
According to Lightfootcycles, the name tadpole came from the "wiggling" caused
by leg movements, similar to python PSI? They also have a long pros/cons list,
but seem to favor delta trikes (that they make)
http://www.lightfootcycles.com/trikecomp.php Henry (Jetrike) discussed in
depth on braking & turning, and favored the tadpole for larger tilting range,
http://jetrike.com/tadpole-or-delta.html.
Cargo / weight
distribution is another good deciding factor for a delta or tadpole. If the
load is a large
flat solar panel in my case, it seems that placing it up front would give
better weight distribution for a FWD. Plus having the electric motor in the
rear tadpole wheel may be simpler than in front delta wheel.
Last, the curiosity factor of building a tadpole is huge :) with possibilities
of sharing frame/module with a exiting bike or delta trike. Yep, the Guinea
Pig needs one more module to go from bike to delta/tadpole/quad,
http://www.youtube.com/watch?v=0cy50C1Lhjw
Cheers,
ViFrom: Gerald <bepb@xxxxxx>
To: python@xxxxxxxxxxxxx
Sent: Friday, September 2, 2011 11:27 AM
Subject:
[python] Why a Tadpole?
Hi All,
It is not that I like to discourage creativity - inspired by your ideaes, I
have been thinking about a tadpole python design myself.
But actually what specific advantage one like to gain from the tadpole python
design? Just to have something to aim for.
Gerald
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