Wednesday, January 18, 2023

Grandfather rights

Well, that is good news! I have just heard from Stefan, the Chair of Cyclekarts GB,  that the committee has just approved my variation to the rules regarding wheelbases, which were formally promulgated just after I started my build. Ordinarily under the Cyclekart GB rules, the centre-to centre wheelbase can't be longer than 66", and a car should be scaled to fit that. 

I wrote to Stefan back when the rules were being formalised, pointing out that the Bédélia, pro-rata with its width, had been unusually long, so that when scaled down, in order to look like what it pretended to be, with wheels in proportion to our 17" ones, a cyclekart would need a 72" base. He took my point and reassured me, back then, that he didn't think it would be a problem.


We car builders were recently invited to apply to the committee, justifying any design features which were at variance with the rules, if we had started our builds before the club rules were formalised. I knew the application was being considered, so I was a bit concerned. It could have been disallowed. That would have been unfortunate because, if you can't race with the club, there are currently no other race options for this class. And of course, you can't drive them on the roads.

In law, "
Grandfather rights is a provision in a new law that allows old rules to apply; as such it provides exemption from having to follow new legislation".

Being given grandfather rights in the year I turn 60 seems somehow appropriate.

Many thanks to Stefan and the Cyclekarts GB Committee.


Saturday, December 31, 2022

Pitch perfect

One of the things I really love about building this cyclekart is that I learn about things which I start out knowing nothing about at all, and today it is the naming of the parts of my main drive chain. And for that I consulted a site recommended by Stefan Nahajski, the Chair of Cyclekarts GB: the Cut Price Racing Guide.


picture from Renold.com

picture from hammerinhandcycles.com

This afternoon I measured the circuit my chain will travel round - when stretched around the driving and driven sprocket - in mm. Then, you just divide this by the pitch of your chain, which in the case of my 420H chain will be 12.7mm and that gives a total number of 92 links, which is what I need to order, bearing in mind that one of them will be a joining link.

Thursday, December 29, 2022

Quick reminder of where this project started

Follow these links:

The concept car 

The mocking up

A chance to see a real Bédélia in action

The faux driver: Monsieur Bourbeau

My work-in-progress on its first outing



Drop-in engine frame

 I have constructed an engine frame which can be pulled out of the engine bay with the engine mounted on it. This makes it possible to keep the engine alignment if ever the engine needs work and access is tight.


engine bay with brackets to hold blue frame

blue frame dropped in 

The engine plate, which is welded to the frame, is slotted so that the engine can be slid back in it, if ever I need to take up slack in the chain.

To brace the engine against sliding towards the drive sprocket (and to assist with alignment) I have welded some nuts at the rear of the frame, so that tightening bolts can bear against the engine base. This last innovation is not my own. Another cyclekarter shared the idea on Facebook recently.

align and brace

alignment checked

engine in














Tuesday, December 20, 2022

skates

An algorithm read my mind and offered me these three wheeled casters. I got some and made skates for slipping under my kart so that it can be moved around easily, as I have little room to work in.








Monday, November 28, 2022

adapting steering box and fitting thrust bearing


Thrust bearings come in inconvenient sizes, for my purposes anyway. The closest size was far too tight, the next size up allowed too much slop. So, to take up the slop I made a bushing, but without a lathe (as I don't have such a thing). I cut off some steel tube, slit it and widened it, made a platform out of a slip of box section (to accommodate the weld connecting the collar to the box), fitted that round the collar (which slides up and down and round the pillar), allowing room for the slit tube, then after hours of grinding and filing, fitted the tube around the collar and inside the raised platform, welded it in place, plug welded the platform to the box and fitted the bearing sandwich with room to move but minimal slop, and made a sheet steel super-washer to sit the spring base on.

All told, it works well.


The raised platform absorbs the weld fillets so that the spring will sit on a turntable which is flat.
Ready for the top bearing washer and the spring base washer. Then the spring.





Monday, November 21, 2022

buck

I have been working on my buck. It is so frustrating. You do a fabulously accurate, dimensioned drawing, then as soon as you start cutting you get all sorts of errors arising from blade thickness, material thickness, etc, and a fine plan ends up looking really dreadful. But at the end of the day, this is just something to lay my metalwork over to understand where I need to stretch or shrink the aluminium to make the cowling. You also need to appreciate that the cowling will be about a centimeter shallower - when the base is removed. 

 have needed to make it slightly higher than the original, to give my hands room to move on the top of the steering-wheel, and you need to appreciate that the steering-wheel, which I am hiding under the cowling, didn't exist at all in the original.

As it stands, the buck covers more of the cockpit than it will in the end because it will have a cut-away which slopes forward on each side.







Grandfather rights

Well, that is good news! I have just heard from Stefan, the Chair of Cyclekarts GB,  that the committee has just approved my variation to th...