Another FWD Delta trike.

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Today was another bit of mocking-up to check & recheck if I am barking up the wrong tree (as opposed to just barking-mad).
This time we have 3 major components all clamped together in layers to see what the end-result might look like and to check some of the critical dimensions.
The spar with the pivot on is monstrously heavy a little bit heavy :( but most of that is the industrial strength tube & the 2 TRB's.
When assembled as shown below I can still step over the front wheel and step backwards and the front edge of the seat is where I need it to be.
This, all without any steering gear/bars in the way (as yet). The option to use "tank steering" has been briefly discussed but my preference would be for a traditional "bars fixed to front frame" solution.

If I keep the entire front half detachable via the 2 bolts that hold the pivot carrier to the spar at the front then disassembly for car transport is very viable and probably desirable.

Having checked the critical dimensions I can see that the front spar with the pivot can be shortened and attached further rearwards (rotating the BB shell further forwards and clockwise) while the arms of the front frame that connect to the pivot can be shortened (movingthe BB rearwards) to keep the BB axle in the correct orbit/distance from the seat mounting point.

Still lots to do, but I am limited in how much I can do in one go at the moment.


 
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Definitively going to be a odd looking beast , sort of like a camel ? a horse designed by a committee...

.. yes I know I stand need to talk :-



Just missing the 24" wheels ........ or is it ?

Paul
 
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Definitively going to be a odd looking beast , sort of like a camel ? a horse designed by a committee...

.. yes I know I stand need to talk :-



Just missing the 24" wheels ........ or is it ?

Paul
Yes definitely like a camel and will probably ride just as badly. :)
Talking of odd looking trikes.... look at the one above this text! :eek:
 
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Still plodding on with things.
Here is the pivot shell (removed from the carrier) and a short section of 25mm @ 2mm square tube shaped to fit onto the pivot shell and to be welded to it.
Cut out with zip-disc, rough shaped with a flap-disc and then hand-filed.

All this metal is adding up to one really heavyweight beast (a bit like the proposed rider 😟 ).



Despite how it looks here, it will be welded on square ;)

 
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Wow virgin steel , now that's spending money !

Paul
 
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In a further insult to the TIG welding art I managed to attach the frame element to the pivot sleeve.
I really dislike trying to do fillet-welds on a curve. :eek:
Mine came out so badly [ in fact they were 💩 ] I was forced to resort to several passes of the weld-bead adjuster.

I then added two outrigger arms that will be used to mount the handlebar clamp-tube.
I didn't bother to even try to weld the infernal internal corners as there are already 3" of weld on each outrigger and a 4th just feels like hard work overkill.
I used far more filler on the welds than is required but I don't think I will bother to dress them back down (we will see).



So when this monstrous malarkey is mounted back in the pivot carrier and on the frame spar it looks like this (the long tube is just there to illustrate where the handlebars will plug in).


There will certainly be a lot of articulation available to the steering.
I may have over-cooked it and the outriggers may be too long (easily rectified) and the handlebar clamp-tube may strike the underside of the main keel when this is all put together.



The OTT heavyweight materials being used are perhaps unnecessary but having injured myself far more than I bargained for (or realised) in my last "build-failure" I really do not and can not risk a repeat performance.
Although it has to be said that accidents are not always as a result of a frame/build failure.
So if the result is a really heavy frame then that's just too bad - So there! :p
 
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.. I do like a lot of lock :giggle:

Paul
 
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Today I tried to attach the frame to the pivot.
It did not go well. :(
We seem to have something "off-true". :eek:
The frame is not true to the spar that the pivot is attached to.
Not sure what I can do about it yet. But its not pleasing to look at and it probably would be awful to ride.

I may have to cut it back off and try again.

 
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Update...
Not willing to be confounded I thought I would do some measuring to see if I could determine where the "skew" has crept into it all.
So I put the spar in my bench vise and packed it all out with wood & steel to be pointing "dead-ahead".
First measured point for reference is the spar itself. How vertical is that in my vise?
Not bad, the vise is holding the spar at 89.87 degrees (biased in an anti-clockwise direction as we look at it), so the bench vise is 0.13 degrees off vertical.


Then I measured the arms of the frame that I made as they present forwards from their attachment to the pivot.
Hmm... 0.2 of a degree off horizontal, but remember the vise is 0.13 of a degree off vertical.
It depends in which direction, this could mean the frame is either 0.3 of degree off horizontal OR 0.07 of a degree off.



But up at the face of the BB shell we have 89.17 degrees a whole 0.83 of a degree off vertical but in the opposite direction?
Remembering the other end of the assembly is 89.87 degrees we are still talking about one degree out of true (0.13 off at one end and 0.87 off at the other)?


The annoying bit is jus how bad it looks with the wheel in the frame. :(

Definitely time for some sulking thinking. :(
 
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Dan

If it is any consolation the front of Python number one was always off vertical , trike never seemed to mind and I only found it slightly annoying [ and a help ] as the wheel was tipped over slightly to the left giving a great view of the sprockets and chain.

The only bike/trike you can ride and watch both derailleurs working whilst still looking ahead :D

From your pictures it is very hard to judge what is bolted and what is welded and what the last operation was that resulted in this misalignment ?

As it is the wheel that you want vertical can this be corrected when you weld the large section piece to the main spar ?

Paul
 
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Dan

If it is any consolation the front of Python number one was always off vertical , trike never seemed to mind and I only found it slightly annoying [ and a help ] as the wheel was tipped over slightly to the left giving a great view of the sprockets and chain.

The only bike/trike you can ride and watch both derailleurs working whilst still looking ahead :D

From your pictures it is very hard to judge what is bolted and what is welded and what the last operation was that resulted in this misalignment ?

As it is the wheel that you want vertical can this be corrected when you weld the large section piece to the main spar ?

Paul
Paul,
All is welded except the pivot-carrier to the spar.
Maybe I have not done such a bad job then? :cautious:
 
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Looking at it from the spar-end I think I could just slice through the LH weld of the drop-out section of the bike frame and pull it over by 1mm and that might straighten things out.
Everything else is pretty good.
 
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Early this morning we had a session at Dr. Stormbirds "frame correction clinic" and several ideas were put forward with regard to isolating and correcting the evident frame "twist".

This afternoon the frame was sedated and taken down to surgery where it was sliced & diced in two places after a session on the "rack of trueness" (engineering blocks used to determine which frame members were at fault).
As suspected, one of the "strengthening struts" was pulling the frame awry.

So after a bit of further pulling around and inserting a slice of metal into the foot of the strut and welding it all back up again the frame no longer "rocks" like a 4 legged table on uneven ground when sat upon the engineering blocks on top of the bench.

When the wheel was reapplied it was found to be a bit more difficult to insert into the dropouts but is parallel to the spar that the pivot is mounted to.

It is however clear to me that the wheel will required "dishing" to get the rim to run more central to the frame.

So, I think we have resolved the problem discovered yesterday. :)

BTW, my laser plumb-bob crosshairs thingummy also showed what was in line and what wasn't.


 
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When the wheel was reapplied it was found to be a bit more difficult to insert into the dropouts but is parallel to the spar that the pivot is mounted to.

It is however clear to me that the wheel will required "dishing" to get the rim to run more central to the frame.
Was the wheel dished correctly when built and fit before ? or is the tyre causing the problem ?

Paul
 
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Was the wheel dished correctly when built and fit before ? or is the tyre causing the problem ?

Paul
Dunno.
I may be chasing another problem here.
Let me have a play around with it and see.
I didn't do any dishing on the wheel at all.
I will look the hub up and see if it requires dishing.
 
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If the tyre clears the frame and you are not using the brakes does it matter it is not dished ?

Paul
 
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Nope the hub is symmetrical.
http://kstoerz.com/freespoke/hub/198
So there's something else happening.
I may get a chance to play with it later today to do some measuring of the frame.
But as you say, its clear of the frame on both sides, so it may not be an issue.
 
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Well, we are all sorted (sort of).
The wheel is running back square & true in the frame (as far as I can tell). (y)
Puzzling is the fact that I cut it open, clamped BOTH sides down to the benchtop on packers, tacked it and checked it was true still.
Welded it up a bit more and then put the whole thing together with the wheel and it looks fine.
Take the wheel out and put it back on the packers and one corner is no longer level with the others. 😟

I am fed up :mad: chasing this particular ghost so it can stay an unsolved mystery.

Onwards and sideways upwards. :p




 
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Take the wheel out and put it back on the packers and one corner is no longer level with the others. 😟
So you don't think the clue is in ' Take the wheel out ' ?

Paul

ps seen you have lost the shock non absorber , looks much better..
 
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So you don't think the clue is in ' Take the wheel out ' ?

Paul

ps seen you have lost the shock non absorber , looks much better..
Yes, but the same frame (without wheel in it) was perfectly level before.
Something in the sequence from "tacking" to "welding" has caused it to twist again (like we did last Summer ;) ).
I wonder if I should put the spar on crooked to compensate? :unsure:
 
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