[python] Re: Pythonjetrike

A few of my friends were laughing at the idea of a bicycle without a handle bar, so I thought I'd better put two on them ;-p

Just kidding of course...
My Python already had a handle bar for steering and the trike has the same front. The other handle bar is for controling the leaning, because I read on Henry's website that he was unable to stop without falling to a side. The other reason was that I was unsure about the forces that the trailer would carry over to the trike and I thought a handle bar could aid in staying in control. But after some test drives, I am quite sure that the handle bar for leaning is not needed. The loaded trailer doesn't seem to push me to the outside of a corner. And driving on an uneven (chambered?) road doesn't make it a nasty trip, although that does depend a bit on the linkage settings.
The handle bar for steering is not at all needed for steering (unless for very tight turns), because the trike handles so much easier than the two wheeled Python. Cycling hands free is dead easy. But I do like this handle bar for a different reason now: to apply force on the pedals. It is the same as with my underseat handle bars of my RWD recumbent; when I push hard on the pedals my body goes up in the seat, but I can counter this with pulling the handle bars with my arms. The trike in the current setup seems to have some wobble at a certain cadence when riding hands free, so then I use the bars as well.
The initial idea was to test both handle bars seperately and later combine them into one (for the next bike project). I was planning to make one handle bar that controled steering when turned left/right and control leaning when turned up/down. Nice idea, but not needed anymore.

I will have to wait for new rod ends, since my installed ones did have some play after testing. I did some calculations, but there is a considerably force going from the swing arm to the rocker arm. I did realize that the arm lenght difference multiplies the forces like 5 times, but probably the rod ends of this strenght/size can't cope when the rear wheel hits a bump at higher speeds. Probably I will also make a new rocker arm and remove the handle bar.

Henry, again an interesting design! Good luck with testing/tweaking the prototype.
Patrick

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From: whpthomas@xxxxxxxxx
To: python@xxxxxxxxxxxxx
Subject: [python] Re: Pythonjetrike
Date: Sun, 4 Sep 2011 07:31:43 +1000

Well done Patrick!

I love the way you have resolved the trike design with the two handle bars. It seems like you will get the best of both worlds. Being able to lean and being able to control the lean at low speeds. I am really looking forward to hearing your ride report - and maybe a video on Youtube of you riding it ;)

These days I have been working on something completely different. A bike you can run on - here is a glimpse of my first prototype.

-h

Henry Thomas

On 04/09/2011, at 5:34 AM, Patrick van Gompel wrote:

Recently I have finished my Python and Jetrike combination. See http://cycle.free-creativity.com for pictures.
The trike handles rather well and will do duty as a utility vehicle to pull a big trailer. I still want to redesign the front part to get a better strenght/weight ratio and add mountings for a fairing. But that will be a next project. Adding rear brakes will be first priority.
Many thanks to Jürgen and Henry for sharing their ideas! It really helps when you don't have to start from the bottom.
Patrick