Scaling Up Plans?

I want to scale up a plan. Take for instance the wing span. eg 32 inches. I want to make it at 48 inches. If I can work out the ratio of scaling up then I can apply the ratio to all dimensions. I have tried to solve it using some maths but the latter not my best subject. I have tried online formulas but these ask for scale ratio in first instance. ie; 1/32 to 1/24. Not what I want.

Help much appreciated.

Hi Phil, divide 48 by 32, this gives 1.5. Multiply all dimensions on the 32" plan by 1.5. If using a calculator, key in 1.5 as a constant. All you need to do then is key in the dimensions of the 32" plan the conversion to the dimensions needed for the 48" version will be automatically displayed.

Phil.

Having faced the same problem when I built my 5ft span Frog Janus using the original 44" span plans (a 136% increase) I know you have a scanner so just set it to 150% and scan the plan in sections which you can then print out. Finally taking a large roll of sellotape, assemble your plan for the larger version. Job Done. Alternatively take the plan to photocopying centre like Hobbs 178 Old Christchurch Road, Bournemouth, Dorset, BH1 1NU and get them to do it for you.

Happy building!

Sheet Balsa should turn up tomorrow from SLEC but not sure when to start on the next weird n wonderful. When the snow arrives maybe.

Is there not anywhere else than can scan and print large plans from the original other than David's suggestion?

Any copy shop will be able to do it. XeroCAD in Ferndown. Office Outlet (Staples) in Bournemouth...the list is going to be endless.

A few things to watch out for:
When you scale up a plan like this all of your wood dimensions will be increased but you don't necessarily need to use larger stock. For example, a 32" model might use 1/8 sheet fuselage sides and 1/16 wing skins. A 48" model would probably use exactly the same sheet sizes but your photocopied formers and ribs will not take this into account.
Notches in formers and ribs for stringers and spar caps will be bigger than a standard size and you will have to fettle a bit to make it fit.
A scaled up model will tend to look out of proportion. A small model needs a larger tailplane (as a percentage of wing area) and whilst these large tailplanes look right on smaller models it does tend to look out of place on a larger one.