Wheels with motors
This section provides a showcase for the many talented model engineers in West Wales. It's an opportunity to find out about what others are doing and hopefully find ideas and inspiration that you can use for your own modelling.
There are 2 sections-the first is for wheeled models with motors and the 2nd for wheeled models, as there are some amazing examples of model buildings such as farm carts and vehicles.
Trev Ford provides our first contribution and those of you that attended the last WW0GG show may recall his tank. Trev's expertise is shown below.
All hand built byTrev, these are all fully operational tracked vehicles.
From left to right T54, T34, T 43. The numbers refer to their length in inches and all were powered by petrol engines. 4.5 hp for the T54, 23 cc: strimmer 2 stroke the T34 and a 35 cc 2 stroke chainsaw engine for the T43.
From Doodle to Design Of the 8x8
Thought I might attach two early sketches for my 8x8 vehicle, as it might give some idea of the Yaw and Roll set up.
I sketch out most aspects of a project, from total overviews to individual details. Most evenings I sit and sketch in A5 sketch books, a range of ideas as they enter my mind ( Di says I am pretty mindless so they probably do not amount to much!! ) and for each model several hundred are produced, although not all end up as part of the model design.( and not all in one evening!!).
From these sketches working drawings are produced, using 5mm. squared graph paper for details or wall lining paper for full size views. Where possible I like to work to "base 5" dimensions that is in multiples of 5mm. but this often conflicts with the milling Mc. and lathe lead screws of 2 and 3 mm. pitches. Thus, it is in the main only used for bodies and superstructures.
Quite often castings and other parts are designed to encompass standard commercial components, such as ballraces, silver steel rod and sheet metal hole saws. For example, the 8x8 ballrace housings shown in earlier pictures, are cast to a size that when machined will fit a 76 mm. diameter hole saw size and house a 68x40x15 ballrace.
Anyway, that is enough nonsense for today, stay well and safe
From Drawing Board to 'turning good ideas into action'
I have been working on the new project, an 8 x 8 wheeled vehicle, using two battery powered mobility scooter drive units, passed on some time back by the greatly missed young Dennis, to power a pair of articulated bodies. The first power unit was stripped down to make a silicon rubber mould from the differential bevel gears, and with great skill I managed to lose one of the bevel gears, it now resides in the part of my workshop that bears a great resemblance to the Bermuda Triangle. A brass replacement has finally been cut, after much study of the arcane and mystic art of bevel gear cutting. Having donated my last £500,000 to the "Replace Johnson with trump" campaign I now lack the money to buy a Fellows or Gleason gear cutting machine, so in the end I employed a method last used in about 1870, and well suited to my workshop setup. The hope is that now I have a replacement , the original will reappear.
Castings for the wheels and various hubs have been machined and the four centre pivoted walking beam suspension unis assembled, now onto the plywood bodies.
Attached are some photographs, various moulds and castings for the hubs and wheel rims, two of the walking beam units, the top is the outer face , the lower the inner face with the final chain drive ( the tyres are 11 inches in diameter), The diff. bevel with a brass turned blank along with the original gear and the machined brass replacement.
Trev dressed for his favourite hobby!
This is the T 54 demonstrating its walking beam suspension in action
The T54 halfway through construction. Note the plywood hull, cheap, quick and simple build. It has braked differential steering, modified mini differential and go-kart disc brakes. Also Windscreen Wiper motor actuators -- not a successful system!
This shows that the T 54 simple belt drive controlled differential. The 2 loose belt pulley trains have a different ratio to that of the differential chain drive from the lay shaft. When either belt is tensioned its half shaft increases speed, compelling the other shaft to rotate at a lower speed. The sum of their speeds equals twice the differential speed but at a ratio determined by the pulley train ratio from the lay shaft.
The difference in how shaft speeds gives a pre-set steering radius.
Trust me it works!!