[python] Re: Why a Tadpole?
- From: Vi Vuong <vi_vuong@xxxxxxxxx>
- To: "python@xxxxxxxxxxxxx" <python@xxxxxxxxxxxxx>
- Date: Sun, 4 Sep 2011 12:58:58 -0700 (PDT)
Hi All,
Yes, let us limit ourselves to FWD and pivot turning mechanism,
and leave RWD aside on its own. Tadpole front wheels can be
covered by the front shell piece / fairing, while delta rear wheels
cannot be covered by the sharp tail of a streamlined shell. With a
differential, in case one tadpole wheel slips, the other wheel can keep going.
Plus tadpole wheels can be placed closer to COG for more traction than delta
wheel, especially with bigger wheels / shorter riders. I am wondering if term
"reverse trike" should be clarified as FWD tadpole is like a reversed FWD
delta, and vice versa with RWD tadpole and FWD delta...
Yes, steering/braking is complicated with load/speed involved, and may be just
as difficult to build as FWD differential. Regarding control, I am hopping
that steering 2 wheels with my feet would be easier than 1 delta wheel.
Theoretically more may be better, but practically less may be more?
Thanks for the design primer pdf.
Vi
>________________________________
>From: Patrick van Gompel <patrick_van_gompel@xxxxxxxxxxx>
>To: python@xxxxxxxxxxxxx
>Sent: Sunday, September 4, 2011 11:33 AM
>Subject: [python] Re: Why a Tadpole?
>
>
>
>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,
>>
>>
>>Vi
>>
>>
>>
>>>________________________________
>>>From: 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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