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My brain hurts!

Posted: September 15th, 2018, 1:32 pm
by Steve Mansell
Hi,
If I have a set of 1/6 scale plans, but require 1/4 scale, how do I work out what percentage increase I need to tell the print shop?

I'm not to bad on excel, but need a formula.

One for all you maths wizards!

Cheers
Steve

Re: My brain hurts!

Posted: September 15th, 2018, 2:37 pm
by Mike Ellis
Not being any good at maths either, how about finding out the span, length etc of the full size one you are modelling.
Once you know that, devide by 4 and thats 1/4 scale !!

Re: My brain hurts!

Posted: September 15th, 2018, 3:22 pm
by steven patey
https://www.instructables.com/id/Copier ... one-Right/ the general principle is explained here.

Steven

Re: My brain hurts!

Posted: September 15th, 2018, 4:34 pm
by Mike Ellis
Nope !! Didnt get any of that lol
Surely if you want something of a measured size to fit into a space of another known size, hat principle works, BUT if you need to know what 25% of a KNOWN size is then it dosent!
Eg: full size = 36 feet (span) so 25% = 9 feet.
So tell the printer who will print your plan, that you wish the plan supplird to them,that measures 6 feet (1/6 full size) needs to be enlarged to 9 feet !! Thats what I tell the people who print for me and it always works lol

Re: My brain hurts!

Posted: September 15th, 2018, 5:06 pm
by maurice northcott
Steve

I always take 100 divide the the scale you have, ie in this case 6 = 16.6666667

Now take 100 divide by the scale you want, ie in this case 4 = 25

Then divide the 25 by 16.6666667 = 1.5

So you want your 1/6 drawing enlarged by 1.5 OR (in other words) you want it enlarged 150%

Simples :-)

Re: My brain hurts!

Posted: September 15th, 2018, 5:09 pm
by Mike Ellis
Now even I can understand that !! Well done Maurice!!
Simples!!

Re: My brain hurts!

Posted: September 15th, 2018, 5:17 pm
by maurice northcott
Always bear on mind you must check:

(a) Is the original plan correct or has it shrunk or stretched in the printing process?

(b) Is the enlarged plan the correct size? Calculate what a couple of key dimensions are (eg length and width)before you leave home, take your rule of choice with you (inches or mm) and check the enlarged drawing before you leave the shop. You may need to make "slight" adjustment when you get home, but how much "adjustment" is acceptable to you is personal choice.

Good Luck matey :-)

Re: My brain hurts!

Posted: September 15th, 2018, 6:30 pm
by David Baker
Usually work from 1/72 scale 3 views of the original aircraft... which is really useful as it also makes it easy to scale things up from a 1/72 scale Airfix kit..
just get your “multiply by number” and you have a 3D reference

Re: My brain hurts!

Posted: September 15th, 2018, 7:33 pm
by Steve Mansell
Magic!
Thanks all.
I can do a small spread sheet with Maurice's calcs, so I will just need to input the original scale and required scale and viola! off to the printers.

Ta very much
Steve

Re: My brain hurts!

Posted: September 16th, 2018, 9:33 am
by ian redshaw
Before you get the plan copied, draw two lines at 90 degrees to each other, on each sheet. I draw the lines to a length that once enlarged come to a known measurement and write "these lines to measure 500mm on the finished enlargement". This saves any hassle when you pick them up, it also gives the operator chance to get them spot on without the customer being present, making it a much more pleasurable task for them.

Ian.

Re: My brain hurts!

Posted: September 16th, 2018, 3:31 pm
by Steve Mansell
Thanks for the tips.
Still undecided on subject, but will be an early WW1.
It will be a linen covered fuselage, as I have just finished an Albatros C.iii, and the ply covering meant a lot more lead up front than I wanted. (It also cost a fortune!)

Thanks all again,
Steve