Scaling Irregular Shaped Parts ?
02-01-2021, 06:31 AM
#1
Thread Starter
Scaling Irregular Shaped Parts ?
What's the easiest way to enlarge or reduce irregular shaped parts without the use of cad programs or sending to a printer? Would like to resize some formers . Thanks
02-01-2021, 07:45 AM
#2
Oh, a hard to answer question! "Lofting" is the term you want to search on. Usually used to figure out the in between between two shapes (ie - round cowl former transitioning to a square tail former - how should the middle formers be shaped?) But it can be used to scale up already determined shapes, too.
Used to be done with a compass, rule, and math....
The hard part is finding "how to" using just pen and paper. I remember old articles about it in model magazines, but apparently no longer in my stack of saved things.
Closest I could find on-line was: Lofting-3 view drawings
Scroll down to the bottom, with the pictures of pages from an old model magazine. While that article does reference CAD, he goes into the "how to", which may help you to do it by hand.
Used to be done with a compass, rule, and math....
The hard part is finding "how to" using just pen and paper. I remember old articles about it in model magazines, but apparently no longer in my stack of saved things.
Closest I could find on-line was: Lofting-3 view drawings
Scroll down to the bottom, with the pictures of pages from an old model magazine. While that article does reference CAD, he goes into the "how to", which may help you to do it by hand.
02-01-2021, 09:14 AM
#3
My Feedback: (20)
Back in grade school we learned a technique where you take the drawing of the original object and overlay a grid of squares. Typically 1/4" squares will work. Now draw a grid with squares larger by the percentage you want enlarge. For example to double the size draw 1/2" squares. Then draw in each big square the lines that were in the corresponding smaller square.
Chuck
Chuck
02-03-2021, 05:01 AM
#4
Thread Starter
I took tracing paper and drew a x y coordinate system on it. Measured from the x y lines to plot the reduced shape and used the grid system as reference to make straight measurements. A little time consuming but it got the gob done.
02-07-2021, 08:50 PM
#6
02-09-2021, 11:26 AM
#7
Moderator
Often, irregular shapes are comprised of multiple standard shapes. A typical fuselage former is a rectangle with a half oval or half circle on top for example. So you might be able to use that method and then the standard methods of scaling.
