(Saturday 21st September 2002: Fuschia Room, Jabula Center, Sandringham)
Tony Gane demonstrated his newly completed model of a fairground octopus, based on a 1950s design by Hugh Henry (and described again by Tony Brown in 1998). The model runs noisily due to a closely meshed set of gear wheels.
The centre-post (carrying the wiring) is a 4mm tube made by a company called Metal Centre in Selby.
The model is built of reconstituted parts, stripped using caustic soda, acid (and, in extreme cases, paint stripper), primed with etching primer and then sprayed with Duco 300 using a compressor. The colour scheme of the model is particularly successful, making use of bright primaries from various stages of Meccano history.
Tony now has enough fairground models to usefully occupy five tables at the forthcoming exhibition.
Dave Heathcote brought a range of models, including the base of a block setter crane. The gearing drive is situated well below the main bearing, based on a design by Cobus Canfer that appeared in the TMG magazine (DATE?). Because of the weight of the top structure and operating gear, it is important to build a very rigid base.
Dave also demonstrated a component of the crane hoisting arrangement, based on a mechanism described in the MMG Magazine, and using a sprocket wheel as a brake.
The longstanding battle between Dave and Peter Feather to produce the world's smallest Meccanograph may finally be resolved by Dave's pocket Meccanograph incorporating Peter's gearing. Unfortunately the 2½x1x2½" model has only two movements instead of the preferred three, so we may yet hear from Peter on this one.
Tony Gane's helicopter (not a Rooivalk) is difficult to fly, but very impressive. The trick is to get the rotor spinning at just the right speed, and then to gently ease the model into a nose-down attitude using the joystick.
Earlier versions became unstable as the model reached the edges of the table, so a metal strip has been added under the circular flight path in order to maintain a constant air cushion beneath the aircraft. (You can find out more on the aerodynamic effects of ground surfaces on low-flying helicopters at http://www.copters.com/aero/ground_effect.html ).
Paul Wright and Ross Ballington are advising on how to prevent the speed control from over-heating.
Dick Anstee demonstrated a Fowler Lion crane engine, based on one that has been restored by Sandstone Estates. The model was inspired by Dick's visit to the Great Working 400 in April 2002.
A worm drive on the base of the hoist replaces the large calliper brake that exists on the prototype.
Fred Konig Presented his number 8 set single-seater racing car, modelled in green and red and based on a design that appeared in Meccano Magazine. It is powered by elastic, using a ratchet so that the wheels run freely once it's rolling. The nicely rounded back of the car illustrates the versatility of well-placed flat strips.
Peter Feather has completed his model of the grab for an iron ore unloader. Each of the claws is made up from two form slotted strips, bolted to a hinge, and opened or closed by levers off a central axle rod that slides freely in a collar. (The 8-claw version is also known as an Octopus).
Jonathan Konig (age 6) has built a house using nickel Meccano strips. Frames and doorways are well modelled. A very good start–keep it up, Jonathon.
Dave's mechanical hand is still in development. It has two main movements: rotating (like a wrist) and opening or closing (to grasp something). Each movement is controlled by a separate motor.
Here's Dave's description of the model:
The mechanical hand was started by building up a compact reduction box to drive the wrist rotation. A worm on the shaft engages a small contrate. This drives another worm to a 1/2" long 19t pinion, mounted on a long threaded pin, affixed by two fishplates to the motor body. This then drives a 25t zinc pinion that lines up with the axis of the motor shaft. Roughly, the reduction ration is 625:1. (Could this be right?)
The two motors are enclosed in a boiler, that is slightly expanded, to give clearance.
Dave's comment: The Meccano reduction box, while being a natty item, only accommodates tri flat axles, and the price is likely to be high! However, comment has been made about the frictional losses of worm drives, and many prefer rubber band reductions for efficiency.
Dave's experimental clock escapement is still a bit rough. It is known as a verge or folio escapement, and uses a vertically mounted crankshaft (part no. 134) as the oscillating shaft. Two springclips on the crankshaft catch in the opposite teeth of a 1½" contrate gear.
Dave's tracked vehicle demonstrates a problem with using the new plastic tracks (part number 177a) to drive a vehicle. The problem is that, when tensioned, the ridges in the tracks do not line up correctly with the grooves in the wheels, causing the tracks to regularly jump off.
Dave also demonstrated a small steam locomotive (more or less 1/70th scale). The model resembles a tank engine without the tank. The black M0 electric motor makes a neat and convincing boiler.
This was one of Dave's first Isomech designs. He recently discovered that Bob Prescott in New Zealand has built it, crediting Dave and TMG for the design. You can read all about it at http://www.dalefield.com/nzfmm/magazine/heathcote_locomotiveDec01.html .
Dave's mini block setter crane is nicely proportioned. It makes use of two girder frames (obsolete part number 113) for the jib.
Dave's miniature tank is made from modern red plastic parts and two or three bolts, and sits on top of his computer. It's made of Meccano parts, but is it a Meccano model?
Steven Manthe has built a child's mechanical digger. The child balances precariously on a sector plate, and manipulates the bucket by means of two levers.
Stephen also displayed a set of Ezy-Bilt parts in a metal box. The parts are very similar to Meccano, apart from some attractive motor tyres. The holes had to be drilled out to accommodate Meccano axles.
Ezy-Bilt is an Australian product, very closely based on Meccano–many of the part numbers are even identical. Tetchel Venn knows of a similar system produced locally in the 1950s, before Maakeets.
Pieter Gouws has built a very well proportioned miniature locomotive. The model (in approximately 1/120th scale) has a particularly strong chassis constructed using axle rods and couplings.
Jeff White has made considerable progress on his model of the giant block setter crane, using two geared plates that he bought for R250 several years ago (these currently sell for R900 each, new). The original-pattern braced girders are no longer available, so cut-down 12½" girders have been used. This has caused difficulties because of the thickness of the parts.
Graham Coombe's beam engine is based on Mike Cotteril's typical steam plant, published in a 1982 edition of Meccano Magazine (poor pictures but very good text). The model uses a quiet-running photocopier motor.
Pipes and other fittings are still to be added.
Frank Ferreira has built a Meccano jig to simplify the assembly of loudspeaker boards. Clockwork-powered robotic assembly line to follow (in red and green).
