Bookmark and Share

Posts Tagged ‘ply’

Straw Man

Wednesday, August 3rd, 2011 by Mick Allan

Over the weekend I remade the box with reference to the manufacturers drawings.

bakfiets dimensionsAll that talk of remaking it in carbon-fibre honeycomb sheet and boxes shaped like cabin cruisers went by the wayside. I like that this is a simple box, and I like that it’s exactly the same shape as the one it came with. There’s something honest and unpretentious about it. But the best reason for making it to the same spec as the factory original is that it permits me to use the manufacturer’s excellent rain cover.

This new box is 40% lighter than the one it replaced – which was itself a replacement of the original. The material used is a mix of 9mm and 12mm beech faced ‘water-proof and boil-proof’ ply. Why anyone would would want ‘boil-proof‘ ply I can only guess. (Actually, I can’t guess. Answers on a postcard to the usual address.)

We are joined in the office today by Dom, a return to the Cyclorama office – he was part of the team which got Cyclorama.net rolling. Good to have him back. He caught up with me on the pedal out to work and snapped the following:

Hay!

When making the new box I did tweak a couple of details: I generated my own curve for the back of the box and also made it possible to stow the seat board by folding it up on a piano hinge. This feature opens up the full load area for cargo and also allows larger passengers to sit on the floor of the box, which makes it more comfortable and improves handling by lowering their centre of gravity.

Seat up

Just a couple more of coats of Top Oil and that’s it done.

There’s a growing collection of imgs on Cyclorama’s Facebook page.

The PlyCycle continued..

Friday, November 19th, 2010 by Mick Allan

Ply-Cycle Specification:

24 inch wheels. Two speed ‘Kick-back’ hub with coaster, linear pull front rim (’V') brake.

The Ply-Cycle is designed to be assembled locally from a kit of parts which could include locally sourced materials. The key feature of this design is the use of two sub-assemblies which are bolted to a ‘frame’ made from inexpensive router-cut ply-wood sheet.

Primary frame components are:

1.       Front sub-frame (fork, steer tube, head tube and handlebar).

2.       Rear sub-frame (seat tube, seat post and seat, chain stays and rear wheel drop-outs).

3.       Pair of frame sides (marine ply or similar sheet material).

The main advantage of this type of construction is the ease of assembly but importantly it also allows the opportunity to make substantial changes to the overall design without expensive re-tooling. By simply changing the shape of the ply-wood frame sides the Ply-Bike can be produced as a standard solo bike, a child carrying bike, a long tail cargo bike, a tandem or in any combination of the above.

Other advantages of this design are that it allows for individual frame components to be replaced should they suffer crash damage and that individual machines can be altered and adapted to suit different requirements without the need for welding equipment or even electricity.

A vehicle designed for Africa using steel subframes and plywood? Haven’t we been here before ??!

Credit where it’s due, this is what inspired the construction of the PlyCycle.

Africar

Unfortunately the very promising Africar project didn’t outlive the eighties.

The question which cannot escape my thoughts is; can the PlyCycle compete? Unavoidably some (indeed most) of the components would need to be imported. Pedals, chains, rims… there isn’t a single factory in the all of continental Africa making these things. So where do we draw the line between what we bring in and what we manufacture on site? Consideration has to be given to supply lines for components and materials – the plywood sheets will want to come from fairly nearby. What about the subframes? The fork? And at what point does it stop being manufacture and become mere assembly?

When my local supermarket can sell a full sized bike for £79.99 (and, heaven help us, even cheaper elsewhere) does it actually make financial sense to manufacture it in Africa? I’m not for one moment suggesting that we send rebadged gas-pipe specials. A bike designed to cope with Africa would have to be be a whole lot better quality than the supermarket offerings but one has to wonder if there is any point in the exercise when established bicycle builders in the Far East can do it so well. And so very inexpensively.

Plycycle

Wednesday, November 17th, 2010 by Mick Allan

I discovered the African Bicycle Design Contest through Bicycle Design Blog recently. Unfortunately I discovered it too late to qualify for entry but I did have a good old think about the subject. Regular readers will be familiar with my Kona Africa Bike and my on-going efforts to make it a more useful machine.

We lived in Africa when I was a child; my father worked as an engineer in Malawi for many years and I remember vividly the big old-fashioned black Raleigh roadsters which were the bike of choice for well off Malawians. With heavy components, single speed transmissions and woeful rod-brakes the only real performance feature was their durability. Raleigh has long since been elbowed out of the market by cheaper Chinese manufacturers but the 100 year old technology has hardly changed. Bicycles have moved on substantially since I was a lad but most African cyclists are still lumbered with those heavy old tanks.

To a rural African the value of a bicycle cannot be overstated. When school, market, the next village or even the water supply might be several hours walk away, ownership of a bicycle can transform a life. Many cycle folk recognise this and work tirelessly to supply bikes to Africans. We’ve discussed the Kona Africa Bike Project at some length but there are very many more dedicated people and organisations working to populate Africa with bikes. Depending on the individual project these include new bikes  (such as the Kona Africa Bike) and schemes which deliver unwanted pre-owned bikes. To my knowledge there is no bicycle factory in Africa, every bicycle from each of these programmes is shipped in.

At the core of the African Bicycle Design Contest is a subtly different approach. The contest organisers invited designers to submit ideas and visions for affordable and sustainable bicycle designs ; ‘Important criteria for the submissions were the usefulness in the African context, innovative aspects in design and manufacturing and market feasibility. Another very important criterion is the sustainability – durability of the design, possibility for local manufacturing, utilisation of local available and sustainable materials‘ (my italics). This is an invitation, not just to start from first principles from a design point of view but to actually create the seed of an African bicycle manufacturing industry.

(It’s been done before with wheelchairs. In 1980something I was working in a London bike shop when a guy came in in a wheel chair and had me fit a pair of protective discs to his wheels. He was about to embark on a journey to India. Twelve years later I was working in a Bristol bike shop when he came in (sporting the same wheel discs). This time around he was director of a charity; Motivation, which works to improve the quality of life of people with mobility impairment. One of the ways they do this is by designing and making affordable wheelchairs for people in developing countries. Motivation now produces wheelchairs from local materials in 17 countries and to date 25,000 wheelchair users world-wide have benefited from his endeavours.)

So. A local bike for local people. There’s a complex set of parameters to consider including fairly straight-forward stuff such as what the range of sizes should be, how many gears, what frame materials and methods of construction. Specifics about how will it be used and therefore what individual features should it have and then more complex considerations; from a spare parts perspective should it use component standards which are already commonly available locally or start with a clean sheet? Should it all be wholly manufactured locally or assembled locally from shipped-in kits? Most importantly (when my local supermarket can sell a ‘full suspension’ mountain bike shaped object for less than the cost of a tank of petrol) how do you design a bike to be useful, durable and yet inexpensive enough for an African wage.

Well I’ve had a think. Furtling my own Africa Bike has been a useful exercise for this and I think I’ve come up with a pretty good design. Modular, versatile, tough and inexpensive. Think plywood sandwich. The Plycycle! (rhymes with bicycle)

Rubbish sketches to follow.

George would like to point out that this is a vast improvement over the original sketch and that it should *not* therefore be labelled "rubbish"

Keep your eye on that competition, I’m really looking forward to seeing the winning entry.