Another FWD Delta trike.

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As discussed with Paul earlier today, a "locking" pin will be introduced on the balance scales to provide a permanent Parking/storing lock to the tilt function.

I have had a jolly-good look and poke & prod around the frame to see what's what.
I can't put the seat much further back than this....... because the rear cross-member of the seat is tight up against the 45-degree seat support.




Measuring from the cup of the seat to where I need a BB to be suggests that the BB really needs to be 33 inches away from there (like on the other trikes).


So I shall put a "prow" of keel-tube on the front of the frame in front of this head-tube and employ an idler pully (with side-plates) for achieving the twisted-chain function.
 
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You could put the rear seat support the other side of the chassis rail if that gives a better seating position.
I looked at that, and it means my spine would be banging on that support beam all the time, so I ruled it out.
I "could" lengthen the keel by 12" but then the turning circle will get a bit silly, so I "could" shorten the trailing arms.
With the prow extension it is all still inside the extent of the front wheel.
 
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... and so after the careful use of some ancient Anglo-Saxon words and the application of the metal-glue-stick a "prow" was added to the laughing-stock concoction that is the tilting delta trike.
Regular (and more observant) readers will note that the boom is much longer than it needs to be for a gentleperson of my stature.
This is a really stupid mistake purposeful design choice; as it may transpire that taller and more northerly riders may (at some indeterminate point in the future) wish to have a ride of this deathtrap wonderful machine.



 
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I looked at the trike, and it just stared back at me with a truculent look on its face.
I realised that it was going to play hard-ball so I made a decision.
Before I invest even more time & energy in this thing I am going to prove it basically works rather than build a "perfect" [sic] trike.
No farting around with a triple-chainring & changer up front in the first pass; it is getting to use a single (middle) ring for "trial-purposes" (makes it simpler).
A traditional 90mm flag pulley will be used as a diverter, a chain tensioner will be used though to allow for "stretch" of the chain run to accommodate turning of the forks.
A smaller skateboard pulley will be used as a return-side pulley.
When I get a break from child-minding and the weather is OK I shall progress these decisions so as to get a chance to test out the viability of this "tilter".
 
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Ah the Chicken of reason rears it's beak......

Don't forget you now have 24" wheels , still you can always use the small ring to start with ? you are fitting a triple aren't you ;):whistle:
 
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This is a really stupid mistake purposeful design choice; as it may transpire that taller and more northerly riders may (at some indeterminate point in the future) wish to have a ride of this deathtrap wonderful machine.
me me me ME SIR ....
 
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Not a great-weather day today and so my time out there "playing" was short.
I disassembled the 2 halves of the trike and put a hole in the frame for a 12mm axle for a diverter pulley. All went well enough.
A chain was found and some preliminary "look-see" positioning was done. I can see that it is going to be challenging to get a FWD that does not foul on the turns.
The weather turned a bit too chilly for standing around outside so I came indoors for a sulk think.
It may be a good idea to have the return idler on a radial arm centred on the same 12mm bolt as the drive-side pulley.
It might also be a good idea to have both these things able to move left & right to accommodate the shift from low to high chainrings (I don't know).

Anyway, that's all I had time for today.

 
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It might also be a good idea to have both these things able to move left & right to accommodate the shift from low to high chainrings (I don't know).
I think you're right. It's a short distance and an ability to move would probably help.
 
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It may be a good idea to have the return idler on a radial arm centred on the same 12mm bolt as the drive-side pulley.


Hard and fixed ?

It might also be a good idea to have both these things able to move left & right to accommodate the shift from low to high chainrings (I don't know).
There are other ways gaining favour for the return idler ?



Or I bet this appeals to you ?



Or a simpler way is to just suspend it on a short length of brake inner cable , then it is free to go where it pleases ?

Don't forget a keeper for the power side idler ?

Paul
 
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Not allowed out to play for long today because of Gym and domestic stuff to be done.
I did manage to fashion a stand-off bracket for the drive-side diverter and I fashioned a keeper plate that will be cut to size (as required)
With some bungee-cord and jiggery-pokery I managed to get a look at what the chain/wheel interference might be like; and the answer is "probably not too bad". Which is a surprise.
Here are some pictures.
 
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You may have to add some adjustable stops for the turning angle of the front forks ?

Why you ask .....

Well your tyres are not smooth and those lumps on them may seriously divert the chain from it's chosen path , this will most likely occur when manouvering the trike and trying to go backwards ?

Now backwards is not generally a direction you think you need chain keepers for !

It happened all the time to my iLean FWD bike/trike and the tyres looked like this :-



failed to ever ride it , in bit's awaiting further inspiration ?



Paul
 
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You may have to add some adjustable stops for the turning angle of the front forks ?

Why you ask .....

Well your tyres are not smooth and those lumps on them may seriously divert the chain from it's chosen path , this will most likely occur when manouvering the trike and trying to go backwards ?

Now backwards is not generally a direction you think you need chain keepers for !

It happened all the time to my iLean FWD bike/trike and the tyres looked like this :-



failed to ever ride it , in bit's awaiting further inspiration ?



Paul
Yes, its early days and a bit of a "look-see" excursion.
I shall put the chain in tubes I think to aid in tyre protection.
But the amount of turn available seemed reasonable to me.
 
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Update Nov 5th 2020:
I did consider just setting fire to the delta and letting off some fireworks, but decided against it and instead I made a simple mount for a chain tensioner and welded it to the forks.


I think the alignment of the sprockets will be ok.


Then I set about making a return side idler with a chain keeper.
It is a skateboard wheel with 2 roller bearings on an 8mm shaft. This will eventually be mounted on the arm that pivots around the 12mm axle of the drive-side diverter pully.
At that point my "Mummy" said I had to come in in case my handy-pands got cold (well, she wanted help unloading the shopping). ;)

At least it is one step closer to a functioning drive-train. :D

 
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No, it is an edelweiss and weighs next to nothing. ;)
 
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Update 6th November 2020:
Domestic duties had to be done first today, but after I had painted the casings of the new front bay-window I was allowed out to freeze in my little workshop.
The end result has been a FWD arrangement that appears to basically work (under "no-load" conditions).

There is a little video and a picture below.


 
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Update 7th Nov 2020:

I did a tiny bit more mock-up and messing around with the trike today.
It seems that with the seat in the ideal place on the main keel I will indeed have the same relationship/distance between the seat and the pedals as exists on the Tadpole.
Next job is to try and sort out how to add some steering capability. USS and a rod attached to the forks seems about right.
 
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