The Search for Shangri-La, Nirvana aka "The Perfect Python Pivot" aka the PPP

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Summed up in one word: creativity, flexibilty, multi-purpose. Choose whichever one you want.
Of course the other consideration is that neither DannyC or I have room to house multiple trikes , however it is very easy to store trike parts ? front ends/rear ends etc and just assemble the trike you want to try when the opportunity presents itself ?
 
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Update Feb 29th 2020:

Storm Jorge was battering us about this morning but after mid-day it all went a bit quiet so I nipped off out to the mess workshop to play with my sparkle-wand.
I had some misgivings about the angle-iron contrivance I had made for the attachment plate for the PPP so I tried something else.
I took a bit of square tube and drilled a 32mm offset hole in it and welded it to the outer sleeve of the pivot.
Here is the end result all mounted into a carrier and bolted to a frame tube.
 
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Dan

Progress .....???

Which end will be fastened to the front ? and which end [ probably :LOL:] the rear ?

Strange how we all see these problems and come up with different solutions?

I would have added another piece of 1.5mm plugged welded inside behind the future mounting holes and then would have drilled the mounting holes , then cut the angles off and then cut off the short side between the angles ?
I then would have welded it vertically to the outer PPP shell ?

Oh and no drilling a 32mm hole ! I mean ?

Still it should all work out in the end ........ else there is the grinder the ultimate adjuster of our stuff !
 
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Dan

Progress .....???

Which end will be fastened to the front ? and which end [ probably :LOL:] the rear ?

Strange how we all see these problems and come up with different solutions?

I would have added another piece of 1.5mm plugged welded inside behind the future mounting holes and then would have drilled the mounting holes , then cut the angles off and then cut off the short side between the angles ?
I then would have welded it vertically to the outer PPP shell ?

Oh and no drilling a 32mm hole ! I mean ?

Still it should all work out in the end ........ else there is the grinder the ultimate adjuster of our stuff !
As you say, this is just "one-way" of doing it, there are many others. Grinders are such versatile creatures aren't they? ;)
I could have done a vertical oriented attachment equally as well/badly, This is yet to be completely finished so I have time to make any mods I want.
 
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Sorry Paul, I wasn't dodging the question....... Honest!
The picture below should help?

 
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Dan

So if you build your front ends like mine that will bolt on nicely :-



As opposed to bringing the back to a point as in a traditional Python ?



As regards your picture the pivot is the middle so there is only 1 front and 1 rear from that point :LOL:

I don't understand the 78' ? your pivot should be around 56' ?



Keep going ...we ALL must keep going .....
 
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Dan

So if you build your front ends like mine that will bolt on nicely :-


As regards your picture the pivot is the middle so there is only 1 front and 1 rear from that point :LOL:

I don't understand the 78' ? your pivot should be around 56' ?
Keep going ...we ALL must keep going .....
Paul, .... yes sorry, I got my degrees in a muddle.
I am hopeful that the 4" of weld material attaching the box-section to the pivot shell tubing and a bit of reinforcement of the box (if required) will be adequate to support a fat bloke sitting pretty close to it.
The degrees of rotation looks sufficiently large to permit proper python-like maneuvering.
The carrier bit in 4mm plate is more than up to the task ;)
 
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Today I added a small insert of 3mm bright-mild steel to the inside of the box section that forms the Pivot 's attachment plate.
I put two 8mm holes through both pieces of metal at 70mm centres. My intention is to spot-weld a captive nut on the inside face and then weld the ends of the 3mm steel insert to the inside of the box section. The 45-degree ends can then be plated over. This will leave the front face of the attachment plate with two 8mm holes with captive nuts behind. Any front triangle I make for this will be bolted on here.
The M8 nuts and bolts shown here are merely there in order to hold the parts in the correct positions.

And YES, the welds need tidying up quite a bit. ;)



 
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What is next front or back ?
 
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What is next front or back ?
Glad you asked, its a tough call.
Clearly I can do either. The most recent steel purchases were materials for trailing-arm pivots and front triangles.
First I need 2D-plan/sketch of the intended layout. I am going to re-use the mesh seat from the WD-Mk2 so I need to work out the seat height etc. so that my little short-fat-hairy legs can still put my feet on the ground at a stop and it isn't a back-wrenching agony to mount/dismount the thing. The central pivot is already on a bit of square tube that I can just cut to length at the appropriate angle to protrude downwards & forwards from the keel, or even mount the pivot carrier to a 4mm plate on the end of the keel. Whether to utilise a tilting beam or to turn any such mechanism through 90-degrees as per Mr. Solar is another decision to be made.
Did you hear anything back from your enquiries in his direction Paul?

Decision, decisions. :eek::unsure:
 
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Glad you asked, its a tough call.
Clearly I can do either. The most recent steel purchases were materials for trailing-arm pivots and front triangles.
err no , see below...

I am going to re-use the mesh seat from the WD-Mk2 so I need to work out the seat height etc. so that my little short-fat-hairy legs can still put my feet on the ground at a stop and it isn't a back-wrenching agony to mount/dismount the thing.
So put the seat mounts on a length of tubing and get it on some blocks of wood and play with the height , no 2D drawings is a substitute for straddling the real mcoy ;)

Whether to utilise a tilting beam or to turn any such mechanism through 90-degrees as per Mr. Solar is another decision to be made.
There is no way you can [ certainly initially ] consider any form of tilting rear end for this trike ?
If you do you will have made a 3 wheel Python bicycle and have a learning curve steeper and longer than the north face of the Eiger on you hands and knees.

I am only considering tilting because:-
a) I have ridden a Python trike for 6+ years
b) It will be wide , some iLean can stand on their own if they are wide enough [ does not mean they are ridable !!! ]
c) I will probably use some tilt resistance/damping [ inner tube ? bungee ? ]
Did you hear anything back from your enquiries in his direction Paul?

No will have to deconstuct from the picture , drawing to follow
 
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There is no way you can [ certainly initially ] consider any form of tilting rear end for this trike ?
If you do you will have made a 3 wheel Python bicycle and have a learning curve steeper and longer than the north face of the Eiger on you your hands and knees.
You can IF you put a tilt-lock on it, so that it can behave as a non-tilter at first while you are learning the "way of the snake".
But I fully "get" your advice here, I do remember the difficulty I had with my 2 minute ride of your Python. I just want to make it "once" (or as few times as necessary).

I can adapt the existing Delta for a Python front-end and the mesh seat, so that's 70% of the frame-work already done. Who votes for this?
"AYE" (said a hired ventriloquist from the back of the hall). Motion carried. Let's do that then. ;)

Just a mesh-seat mounting to make and attach the PPP and make a front tri-mangle. Easy!
 
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Update 3rd March 2020:

Today I finished the mounting plate on the pivot.
The 3mm insert had the captive nuts welded in place and was itself welded into the square tube.
The ends of the tube were capped with 1.5mm plate and this further strengthens the box-section tube as it will resist flexing/twisting/collapsing with all the forces applied to the front face/wall of the tube.

Pointy-ends make for "melt-back" here and there (esp. Corners), but the overall structure is plenty sound enough.








Maybe tomorrow will be a good time to look at the conversion of the front end of the delta frame to accept the mesh seat mount and this box section with the PPP on it.
 
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You can IF you put a tilt-lock on it, so that it can behave as a non-tilter at first while you are learning the "way of the snake".
Unlikely unless you make your tilting end about 30" or greater track ? so it will stand and tip ?

I think there is no way you should rely on a manually deployed lock to hold it vertical , how will your brain decided whether the latest lurch to one side needs just a turn into the turn for recovery [ counter intuitive ? however a Python trait ] or you need to apply the tilt lock ?

if it has lurched to one side a tilt lock will only dump you as you lock the trike at it's tilted angle ?

But I fully "get" your advice here, I do remember the difficulty I had with my 2 minute ride of your Python. I just want to make it "once" (or as few times as necessary).
What exactly was your difficulty ? it is a simple non-leaning trike ?

I can adapt the existing Delta for a Python front-end and the mesh seat, so that's 70% of the frame-work already done. Who votes for this?
"AYE" (said a hired ventriloquist from the back of the hall). Motion carried. Let's do that then. ;)
hmm I think i suggested that 3 weeks ago ? and was reminded you had a 36" fixed rear end for it ?
 
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What exactly was your difficulty ? it is a simple non-leaning trike ?
It wobbled and weebled left and right as one pedalled, and as for steering....... pulling handlebars and battling against one's legs produced a battle only the legs could win (at that time).
I'm sure it is a familiarisation thing. I bet you didn't get steering perfect 1st time either.
hmm I think i suggested that 3 weeks ago ? and was reminded you had a 36" fixed rear end for it ?
Yes indeed, we discussed chopping off the MBB front and putting the Python pivot and a new front triangle on it. Yes, its a bit "wide".
But then you went and tempted me with You-Tube vids of tilting delta's that looked achievable, so I am blaming you for all the delay and prevarication. ;)
This is why I have been considering making an entirely new frame as a tilter.
But! I agree that's running before walking and in point of fact I already have a new Keel (W/O any front at all) that is capable of being joined to the WIDE-BOY suspended rear stuff which is currently part of the MBB frame.
Slap the square tube that has my pivot bolted to it on the front of this new keel section and it would be ready to add a front triangle to.
However, in the long-term the WIDE-BOY suspended rear frame section is just too wide so I can cut it down a bit to make it less cumbersome. But maybe only after a degree of Python steering and control has been achieved.
I accept that the width 36" or 30" may make no real difference in terms of stability, a trike is a trike so maybe I am just being lazy by not cutting it down right away?
Anyway, tomorrow is another day and maybe I will have a dabble with the delta. Who knows? Maybe we will get swamped with grand-kids again?
 
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It wobbled and weebled left and right as one pedalled, and as for steering....... pulling handlebars and battling against one's legs produced a battle only the legs could win (at that time).
I'm sure it is a familiarisation thing. I bet you didn't get steering perfect 1st time either.
If you point a Python down a hill and remove your feet from the pedals it behaves like an ordinary bicycle and is quite stable in a straight line , if you use the bars and nudge it off course it recovers like an ordinary bike.

So we have the legs which don't initially want to take part in any steering and actively resist , making the steering appear heavy and sluggish.

The handle bars are :-
a) somewhere to put the levers within easy reach
b) can be used to get the last few degrees of turn out of it when manouvering through tight turns
c) needed at high speed as you need somewhere for the white knuckles to grip !

I have found it is actually steered by rocking the hips left and right and not as one might imagine trying to move the angles/feet left and right ?
It is possible I could not get the seat far enough forward for the little chubby legs you have ? and you may have had to rock your hips to pedal it ? in which case you would have also been steering it albietly unwittingly ?

Yes indeed, we discussed chopping off the MBB front and putting the Python pivot and a new front triangle on it. Yes, its a bit "wide".
But then you went and tempted me with You-Tube vids of tilting delta's that looked achievable, so I am blaming you for all the delay and prevarication. ;)
This is why I have been considering making an entirely new frame as a tilter.
Stay focused you are supposed to be building ' your' trike NOT mine !

However, in the long-term the WIDE-BOY suspended rear frame section is just too wide so I can cut it down a bit to make it less cumbersome.
I accept that the width 36" or 30" may make no real difference in terms of stability, a trike is a trike so maybe I am just being lazy by not cutting it down right away?
36" is only a problem on:-
a) shared bike paths
b) getting it in the car
c) getting through bike path barriers

So unless a , b, or c are likely at the moment leave it as it is , is the easiest route you still have more bits to build !
 
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Stay focused you are supposed to be building ' your' trike NOT mine !



36" is only a problem on:-
a) shared bike paths
b) getting it in the car
c) getting through bike path barriers

So unless a , b, or c are likely at the moment leave it as it is , is the easiest route you still have more bits to build !
Yes Dad. Sorry Dad.
 
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