My life with Python trikes Mk1 , Mk1.5 , Mk2 ?

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Feb 7, 2008
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Hi all

Tilter #3 = 76 miles

Oh sh*t moments 0/10
Enjoyment 10/10
adventure 10/10
interesting 10/10

So now it is becoming very routine as we crawl towards 100 miles :LOL:

Rolling the Tilter#4 out into the day light ?



So as can be seen rear end overlaps axle , giving a main spine :-



Not to shabby , although before I weld it there I will have it in line vertically and see what the angle is.

The cheesy welds on the elastomer mount are because there seems to be a Zinc coating on the steel and no amount of cleaning seems to remove it.
The mount is only needed because the elastomer anti crush tube passed straight threw 2 plug welds holding the inner joint sleeve in place , so I passed the anti crush tube through both sides and welded it top and bottom.



It has :-

Seat height <> 18"
w/b <> 40"
track 24" [ centre of tyres ]
overall width will be 28"



I will add 3 tubes through the frame at the rear for 8mm bolts in the hope they will be in the right place for a pannier rack , could look neater than loads of clamps around frame.
Light brush with the weld improver and a lick of paint ...

Paul
 
Joined
May 31, 2013
Messages
3,193
Location
South Benfleet, Essex, England, UK
Hi all

Tilter #3 = 76 miles

Oh sh*t moments 0/10
Enjoyment 10/10
adventure 10/10
interesting 10/10

So now it is becoming very routine as we crawl towards 100 miles :LOL:

Rolling the Tilter#4 out into the day light ?



So as can be seen rear end overlaps axle , giving a main spine :-



Not to shabby , although before I weld it there I will have it in line vertically and see what the angle is.

The cheesy welds on the elastomer mount are because there seems to be a Zinc coating on the steel and no amount of cleaning seems to remove it.
The mount is only needed because the elastomer anti crush tube passed straight threw 2 plug welds holding the inner joint sleeve in place , so I passed the anti crush tube through both sides and welded it top and bottom.



It has :-

Seat height <> 18"
w/b <> 40"
track 24" [ centre of tyres ]
overall width will be 28"



I will add 3 tubes through the frame at the rear for 8mm bolts in the hope they will be in the right place for a pannier rack , could look neater than loads of clamps around frame.
Light brush with the weld improver and a lick of paint ...

Paul
Looking pretty good there Paul. :)
Keep the ride-reports coming. (y)
 
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Is number 4 going to be a less meccano and less cobbled together version of number 3? Essentially the finished version of the prototype? If so, I hope you buy a new pot of enamel. The 70's brown stuff on the prototype is not something to be seen on outside a historical documentary on kipper ties and bad haircuts.:p
 
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DannyC & Popshot

Actually the ' last ' prototype I hope , this one is to prove/disprove the need for tilting when the trike is :-

Tilt#4 ------------------------------------------------ original Python
Seat height <> 18" ------------------------------- 8"
w/b <> 40" ----------------------------------------- 36"
track 24" [ centre of tyres ] -------------------- 30"
overall width will be 28" ------------------------- 34"

I will need to have rear axle under main tube as I am losing pivot angle..

Above main tube - main tube 0.6' tail down pivot angle 54.5'
level with main tube - main tube 2.4' tail down pivot angle 51.5'

It is probably ridable , however it will be a lot of bodging to correct if it isn't so best do solution that gives nearest figures .

More of this again :-

This is an illustration of what’s known as path dependence and lock-in.

Past decisions have lingering, unintended effects that we accept without really questioning their genesis. These can make us closed to what might be possible because we confuse what is possible with “what is possible within the way we do things at the moment.”


Popshot are you saying I may need to grow a mustache and wear flairs ?

Paul

ps I don't normally name my build's however i am toying with the idea of a exception for this one ? maybe De-Bugger could be suitable ?
 
Last edited:
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If you are going to paint it brown you need a 70's pornstar 'tache and enormous lapels to go with the flares.
He may also need more actual "hair" :D
 
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Hi all

WELDED !



So after mulling over the options with DannyC and the promise of jigs and clamping big right angled lumps of MDF ...

What did I do .....

Yep winged it :whistle:;)(y)

It is only a prototype after all.

I realised I would have to cap off the main spar if they could not being butted together into a ' T ' shape [ they are overlapped in a ' T ' shape ]

So I cut a piece of 3mm plate bit bigger width wise and about 2.5 times bigger than the 1.5" tubing and welded it to the spine piece on all 4 sides.
That gave me two places to clamp the 2 parts together , vertically over the joint and horizontally under the joint.
When it was clamped and measured to be 90' +/- sod all , I could weld the 2 parts together on all 6 sides , so joint is now very strong and no need for gussets [ sorry DannyC 😥 ]



So we have narrower track...



More vertical wheels with a little camber , maybe 0.25" at top.
hey and I got the rear end the right way around AND the right way up !




So the black piece is original main spine and brown bit new main spine , quite a height difference.

To do ?

Flap disc down and paint
transfer over seat and brake cables
ride !

Paul
 
Joined
May 31, 2013
Messages
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Location
South Benfleet, Essex, England, UK
Hi all

WELDED !



So after mulling over the options with DannyC and the promise of jigs and clamping big right angled lumps of MDF ...

What did I do .....

Yep winged it :whistle:;)(y)

It is only a prototype after all.

I realised I would have to cap off the main spar if they could not being butted together into a ' T ' shape [ they are overlapped in a ' T ' shape ]

So I cut a piece of 3mm plate bit bigger width wise and about 2.5 times bigger than the 1.5" tubing and welded it to the spine piece on all 4 sides.
That gave me two places to clamp the 2 parts together , vertically over the joint and horizontally under the joint.
When it was clamped and measured to be 90' +/- sod all , I could weld the 2 parts together on all 6 sides , so joint is now very strong and no need for gussets [ sorry DannyC 😥 ]



So we have narrower track...



More vertical wheels with a little camber , maybe 0.25" at top.
hey and I got the rear end the right way around AND the right way up !




So the black piece is original main spine and brown bit new main spine , quite a height difference.

To do ?

Flap disc down and paint
transfer over seat and brake cables
ride !

Paul
Well done that man! Will the prototype make a seamless transition to being the "real thing" I wonder? ;)
 
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Well done that man!
Thanks , baby steps..

Will the prototype make a seamless transition to being the "real thing" I wonder? ;)
Well it certainly isn't the ' real ' thing to many flaws , however it does incorporate all the features I would like to see in the real thing.

Paul
 
Joined
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Messages
3,260
Location
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Hi all

Tilter #3 = 88 miles

Oh sh*t moments 0/10
Enjoyment 10/10
adventure 10/10
interesting 10/10

So now it is becoming very routine as the next ride should see 100 miles :LOL:

In a phone conversation with DannyC he tried to suggest the rear brakes were on the wrong way around ?

Now this is an interesting conundrum ?

Is there a right and wrong way ?

Most tadpoles have the cables pointing backwards as they leave the back plate
The Python I ride now have the cables pointing forwards , as they leave the back plate.?

He is correct despite having Front and Top written on the rear axle AND welding it that way I had intended this to be like all my others with the cables pointing forward , the cables will now have to come in from the rear so the same as a tadpole ?

Paul
 
Joined
May 31, 2013
Messages
3,193
Location
South Benfleet, Essex, England, UK
Hi all

Tilter #3 = 88 miles

Oh sh*t moments 0/10
Enjoyment 10/10
adventure 10/10
interesting 10/10

So now it is becoming very routine as the next ride should see 100 miles :LOL:

In a phone conversation with DannyC he tried to suggest the rear brakes were on the wrong way around ?

Now this is an interesting conundrum ?

Is there a right and wrong way ?

Most tadpoles have the cables pointing backwards as they leave the back plate
The Python I ride now have the cables pointing forwards , as they leave the back plate.?

He is correct despite having Front and Top written on the rear axle AND welding it that way I had intended this to be like all my others with the cables pointing forward , the cables will now have to come in from the rear so the same as a tadpole ?

Paul
I could be wrong Paul (I often am), but I understand the SA Drum hubs to be "Handed" because the backplates are actually sold as "Left" & "Right" with different part numbers HSB519 (LEFT) and HSB518(RIGHT).
The design is a "single leading shoe" whereby the forward direction and braking actually drags the "leading-shoe" harder onto the drum under hard braking.

As a test I suppose you could jam the brakes on and then try and turn the wheel in the forward direction and then see how hard it is Vs. the opposite direction? If there is a harder direction to turn against I would think that should reveal something. :)
 
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I think they are only marked left and right to distinguish them from a sales point to ensure you get a matched pair. If you look inside the drum there is a symmetry of moving parts down a centre vertical. Given this symmetry the brake should work just as well either way round. The only thing that will change is the leading and trailing designations swap shoes.
 
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Messages
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I think they are only marked left and right to distinguish them from a sales point to ensure you get a matched pair. If you look inside the drum there is a symmetry of moving parts down a centre vertical. Given this symmetry the brake should work just as well either way round. The only thing that will change is the leading and trailing designations swap shoes.
Popshot is right, it IS purely cosmetic (actuator placement and where it points (front/rear).
I stole this from Sheldon Brown's site. I won't argue with him. ;)
 
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DannyC & Popshot

I perhaps see this as a physics verses quantum physics problem ?

In physics something the weight of a car has very poor braking if it has drums all around and goes in reverse ?

In quantum physics something the weight of a trike makes almost no difference to a drum brake performance going forwards or backwards ?

Paul
 
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Not sure where quantum physics comes in to this. It's simply a function of the actuating system that means it works equally well either way and would do so regardless of the vehicle weight.
 
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Not sure where quantum physics comes in to this. It's simply a function of the actuating system that means it works equally well either way and would do so regardless of the vehicle weight.
I am simple saying you cannot apply car style explanations to trike situations , due to the difference in weights and speeds they behave differently ?

Paul
 
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Overall force and the distribution of force are two separate matters.
The reason it works equally well in either direction is simply a function of the design. Cars with drum brakes almost always use a single double sided slave cylinder to operate them. Whilst this looks similar to the cam system Sturmey uses it differs in one vital area. The double sided slave has no fixed point from which to operate. It's pistons are free to slide both ways. The simpler cam system has a fixed central pivot so must apply force both ways in equal measure. The hydraulic twin piston single cylinder will almost certainly provide much more overall force than a cable cam, hence it is found in cars.
 
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Hi all

So I claim the prize for the AZ member with the most elastomer's ?



There is one more not pictured still on the tilter is a 203 kg one that was sharing the work with a 113 kg = 316 kg
the 113 kg has been swapped for another 203 kg so now the elastomer's = 406 kg !

Why ?

Well each time I increase the values it seems to be easier to control and less nervous to ride.

Currently I have only been around the estate to confirm it does still tilt :giggle: which it does.

Should be out on it Monday all being well.

the big beggar ? maybe I will try 1 x rod end and 1 x elastomer like the Flevo however only tilting the seat , should give me some suspension and the yaw cannot affect the steering ?

Tilter#4 main frame painted and handle bars , decided to make a new seat keel while waiting for the paint to harden.

Paul
 
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We await the CTD reports ;)
 
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