William Fairbairn Scale

[Maryak]

The scale as drawn is pretty close to 1":24" which gives a flywheel of 5" dia (~130mm)and a model height around 9 1/2" (~240mm). Scale 1":12" would give a flywheel of 10" dia (~260mm) and a height of around 19" (480mm). Cylinder dia's would be 3/4" (19mm) or 1.5" (38mm) and stroke would be 1 1/4" (32mm) or 2 1/2" (64mm).

At this stage it is really only a question of numbers but I would appreciate some feed back as to what is most appropriate so I have added a poll to get your ideas.

Best Regards
Bob

 

[RobWilson]

Build it big Bob.
interesting looking engine

Regards Rob

 

[Philjoe5]

Bob,
First off thanks for posting the engine plans/schematics. That's one of the benefits of moving, eh? Personally I like big, so I'll vote for a bore of 1.25" - 1.50". But no matter, because I can always rescale what you publish.

Cheers,
Phil

 

[Brian Rupnow]

Bob---Go for the 1:24 scale. Many of the folks that build these machines don't have the equipment (in terms of lathe size) to build anything bigger. And good on you, for taking the time and effort.----Brian

 

[dsquire]

The scale as drawn is pretty close to 1":24" which gives a flywheel of 5" dia (~130mm)and a model height around 9 1/2" (~240mm). Scale 1":12" would give a flywheel of 10" dia (~260mm) and a height of around 19" (480mm). Cylinder dia's would be 3/4" (19mm) or 1.5" (38mm) and stroke would be 1 1/4" (32mm) or 2 1/2" (64mm).

At this stage it is really only a question of numbers but I would appreciate some feed back as to what is most appropriate so I have added a poll to get your ideas.

Best Regards
Bob

Bob

This will be an interesting project. I voted for 1/12 scale but realized later that I was having a brain fart at the time. What I really wanted to vote for was the 1/24 scale which would be the smaller physical size. I'll be watching when you start building it.

Cheers

Don

 

[joe d]

Bob

I voted for 1: 24 , simply because I run Taig/Peatol equipment, so I'm always having to remember that big is not necessarily better :big:

As Philjoe mentioned, one can always re-scale it.

Cheers, Joe

PS Glad to see you back at it... but don't over-do it!

 

[Maryak]

Well there ya go it's turning into a lizard, (many scales) now how do I wriggle around it. Maybe I can post as a DWG/DXF file and we can all have a play. : ???

Attempt 1 of 1 front elevation at 1":12" little detail just some very basic sizing.

Best Regards
Bob

EDIT I forgot to say thanks to you all for the support and interest

View attachment WFB10tcw.pdf

View attachment WFB10tcw.pdf

View attachment WFB10.dwg

 

[deverett]

Bob

That's a very interesting looking engine.

Even at 1:24 it will be a chunkly little devil. I believe the majority on this forum would struggle with the larger size, hence my vote for the smaller one.

I look forward to your serialisation with great interest!

Dave
The Emerald Isle

 

[steamer]

Can't see the engine on my end Bob...but build her big is my position

A small engine in big scale is great for added detail


Dave

 

[rudydubya]

I voted for the 1:24. I guess I'm just small minded. ;D

 

[Jasonb]

I'd go with 1/12th personally but can see why people would want a smaller one to fit their machines. You have to think through what sizes the smaller parts like governor and rods etc will come out at eg at 1/24th a 1" dia rod or bolt will be 3/64"

A lot will depend on how you see the finished engine - will it be a barstock engine that is just generally based on the layout of the Fairbain in alloy & brass or will it be a true scale representation down to making all the parts look like castings and matching bolt for bolt.

What about 1/16" scale as a compromise? This would give a 7 1/2" flywheel so would fit 9x lathes and you could just make a slightly smaller flywheel to suit the 7x lathe users and still keep the rest at 1:16th scale

Jason

 

[Maryak]

What about 1/16" scale as a compromise? This would give a 7 1/2" flywheel so would fit 9x lathes and you could just make a slightly smaller flywheel to suit the 7x lathe users and still keep the rest at 1:16th scale

Some really good points there Jason - Thankyou. :bow: :bow:

Best Regards
Bob

 

[Jasonb]

Oh and 1/16 makes scaling down nice and easy, if you just measure everything off the original in inches.

1" = 1/16"
6" = 3/8"
12" = 3/4"

If you make a simple spreadsheet in excel you can quickly convert by just looking at it rather than calculating each individual dimension

J

 

[Maryak]

Jason,

Thanks again.

As it turns out, by using a 12" metal scale and reading directly from the original scans, I end up with a drawing at 1" : 24." (Well at least that's what I think I have :)

That's what I propose to do to get a set of working drawings and then thanks to the magic of CAD I can scale to whatever and end up with parts that are workable. I am still a CAD novice but I will experiment with, (in Turbocad terms), associative dimensions which I hope as the scale changes they will change with it.

When one set is done others will be produced to satisfy the poll results.

You are absolutely spot on about relative sizes when reduced, the piston rod as shown is some 2" long, and tapers from 3/32" to 1/16" over that length. Got me whacked how the gland seals - and so it goes. Things like this will IMHO have to be a compromise to achieve a working model, a tapered metallic spring loaded packing at that scale is way beyond my capabilities and I don't think they were around in the mid 1800's.

It will be a barstock engine, (at least the one I make - after the hit & Miss), I hope to use some of the sandblasting techniques described in the forum to get a casting look on some of the major components. I guess it will end up based on the Fairbairn.

More grist for the mill and thanks everybody for all your contributions. Designing the M10 was easier than this but nothing ventured nothing gained.

Best Regards
Bob