Author Topic: Is 12 inches big enough?  (Read 1953 times)

Offline collbee

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Is 12 inches big enough?
« on: January 24, 2014, 05:05:39 PM »
Hi to all  :-) ,

I am about to, hopefully, embark upon construction of  the
 "SWEET SIXTEEN" Traction Engine (Model Mechanics 1979)
  which will be my first attempt at a large project. I would like to
  ask a couple of questions if I may ?

The specifications are as follows:

Length:             12 ins
Width:                6 ins
Height:               7.9 ins

Rear wheels:      4.1 ins diameter.
Front wheels:     2.6 ins diameter.

Wheel base:      7.5 ins

Engine:             Single cylinder, double acting --- 0.5ins bore x 0.6ins stroke.

Flywheel:          3ins diameter. (or maybe larger and heavier - if it will fit ?)

Boiler:              1.5in diameter,  3 x 0.375in firetubes,  2 x 0.1875in. syphon tubes.

Working Pressure:
                               40 psi.  Butane fired.

Gears:                Low ratio .......  15.60 : 1
                                  High ratio .......    9.75 : 1

I have no real expertise on the subject of steam, being a collector of IC stationary
 engines most of my adult life, so I would like to first ask if a model of the above
 proportions is just a shelf model .... or is it capable of being put to work
 carrying/towing a payload of around 178lbs. (me ?

Secondly, if it is not capable of bearing a weight of that magnitude, what
 would members of the forum consider the minimum, suitably sized traction engine
 that would 'putt-putt-putt' round  the back yard with me in tow ?

Collbee. (Qld. Australia.)
« Last Edit: January 24, 2014, 05:21:11 PM by collbee »

Offline Stuart

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Re: Is 12 inches big enough?
« Reply #1 on: January 24, 2014, 05:30:25 PM »
I would say no sorry

To pull you you would need at least a 1 1/2 inch one a 2 inch would be better. To ride on you will need 3 inch or 4 inch

These relate to the inches to the foot of the full size

The size you have postulated would move its self but would be a devil to fire to keep up the steam pressure/water level

My aim is for a accurate part with a good finish

Offline collbee

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Re: Is 12 inches big enough?
« Reply #2 on: January 25, 2014, 07:41:13 PM »
Thanks Stuart ...

I had a feeling that was the case ... just as an aside .... the accompanying text states that she carries enough water to run for 25 minutes.

This is where I start to get lost .... psi vs hp vs load capacity etc etc.

Thanks again,
Cheers ...........