You find out where the companies old drawings and records are archived and see if they have what you want may be a museum or university, find a full size one and get your tape measure out, contact the maker if they still exist and see if they can help. Basically you put in a lot of hard work as most don't come up with a google search.

The patent office (UK) are very helpful and not expensive but be aware that patent drawings can be very unreliable and often show details that are impossible to manufacture. Their sole purpose is to describe an idea or an improvement to an existing one.

Some drawings are very basic with little or no detail whilst others are very detailed but have features drawn incorrectly so as to not make life too easy!

Brian

Airfix (now part of Hornby) use original drawings , if available, and work with museums and owners of preserved machines. They appear to be much more conscientious these days than in my youth!

They use photographs and even paintings for details of an individual subject.

Some of the bigger museums (e.g. Bovington) can supply accurate (hopefully) drawings of some of their exhibits

If you look at photos of the Vickers light tank in the museum its markings have changed greatly over the years despite being nominally the same! So try and use period images.

For the Ha Go I would suggest getting any overall dimensions you can get, and working carefully from photographs.

Different drawings can be very different and even different views from the same drawing are often incompatible.

If a plastic model exists you can cheat and measure it

For things built in feet and inches many sizes will be a convenient number of inches, for example many hand-holds will be 6" long! Things made in metric tend to use less obvious sizes/spacings.

My feeling is to accept some level of error in the detail but aim to get proportions right. Looking at how things are arranged relative to each other is often a good way to figure out (sometimes recursively) how they are sized and spaced. For example, IIRC many rivets on the light tank are 4" apart which greatly facilitates estimating the size of various plates. Beware irregular shaped parts that can look very different from different angles.

One places to go wrong is making handrails and grips too bulky, as these points of 'human contact' seem to impact on how 'realistic' we find a model. They are almost always between 1 1/4" and 2" in diameter, usually 1 1/2" or less. 1/8" makes realistic handrails in 1/12 scale.

For steam engines old engravings are often remarkably accurate.

Not sure if that helps much…

Neil

Rik

The MAP plans were taken over recently by this company**LINK**

Dennis