Scale Question

Dave,

the way to go is to compare the dimensions of the model to the dimensions of the real thing reduced x times - and x is the scale we're talking about. Since most of the time you don't have access to the real thing, you usually take drawings, plans. Photos are not so good, because they distort - like lines that are parallel in one plane on the real thing are convergent on the photo and so on.  Sometimes you find a portion of a photo good enough to compare with your model part. Then you need a measurement/distance that is precisely known for a reference point. Once you have that, you scale (divide by x) this measurement and resize the photo/drawing to match that. Once you're done you can put your model part on paper to compare the shape or dimensions. Hope it helps, have a nice day

Paweł

I have to agree with pawel. I've never taken it to that extreme. Just compare the model to known dimensions and do the math. They are usually pretty darn close

When we use drawings, we really shouldn't be just laying parts up to them. The proper way to build from scratch with a drawing it to use the dimensions given on them to set a measuring device (of choice) with, and use that to check the part.

Anytime you have to check a size that is not called out on the drawing, you set your calipers (I've chosen those for convenience in typing this) to the dimension found by lining up with the distance between the middle of the drawn lines. You do this by setting one jaw up against the outside of one line, and the other jaw against the inside. (the line itself has a thickness, which is HUGE in 1/700, and might change your part from 1/72 to 1/70 in 1/72 scale)

Today is easier than a few decades ago, just measure with digital calipers, or by dividers and a dial or vernier, multiply up to 1/1 from the drawing scale,,,,,then multiply by your modeling scale.

If you learn it right, you can use plans drawn in 1/157 to build in 1/48. If you get a set of what you think are really useful drawings and they don't have a scale listed,,,,,,,find a dimension that you know for some place on the plans and do the math,,,,,or if you are converting an existing kit, you can just measure some kit part that you are not going to change,,,,,in either case, convert your known dimension to 1/1, then divide the drawing's part, and you will know your drawing's scale.

You really don't need drawings for each scale that you want to build,,,,,,you just need "good" drawings in any known scale.  (what is a "good" drawing of anything is a "whole 'nuther" modeling debate, haha(

Rex

Personally, I always like to have a set of drawings the same scale/size as the model. I find that makes it much easier to visualize exactly how the finished product is supposed to look. I know how to take dimensions off a drawing and convert them to model scale all right, but I find it easiest just to transfer the dimensions directly from the drawing with a pair of dividers.

If you're working from a kit (and don't want to modify it drastically), and if you have an all-in-one inkjet printer/copier, you can reduce or enlarge a set of published drawings to match the size of your model.

Caveats: one - the drawing you're copying has to be no bigger than the sheet of glass on your printer/copier. (If it's not much bigger, you may be able to get away with copying it in two or more sections. I once reduced some pieces of a 1/48 scale drawing of the U.S.S. Yorktown to 1/700, but it took about a dozen shots and the lettering wound up illegible.) Two - your copier/printer has to have a reducing/enlarging function. (Every one I've ever encountered does. But if yours doesn't, you can do the job yourself at a copy center like Kinko's.)

Then do a little arithmetic. Let's say some feature on the drawing is 2 1/2" long, and on your model you want it to be 1 1/2". Set up a simple equation: 1.5 / 2.5 = x / 100. (The 100 is relevant because we're trying to figure a percentage.) Do the math on your pocket calculator, by cross-multiplying and dividing: 1.5 x 100 = 150, and 150 / 2.5 = 60. Lay the drawing flat on the glass, key 60 into the printer as the reduction percentage, make the print, and voila! You've got a copy of the drawing that should match your model.

None of this really has anything to do with scale per se. If you want to, though, you can find out how close to the stated scale any part of the model is. Say a prototype airplane has a wingspan of 47' 8", and your model is on 1/72 scale. Divide 47'8" by 72, and you get 7.94" (or 7 15/16"). That should be the wingspan of your model. But don't be surprised if it's a little off.

Once you get the hang of it, that math is childishly simple. If it wasn't, I wouldn't be able to do it. I haven't taken a math course since I graduated from high school, in 1969. If I can work a problem, anybody can.

To my eye (caveat: I primarily build ships, so I'm biased), the precise scale of the model is less important than that every part of the model be proportional to the other parts. If a supposed 1/700-scale model is actually 1/715, I'm not going to worry about it. But if the island of an aircraft carrier is too narrow in proportion to the rest of the ship (do you hear me, Tamiya?), it'll bug me.

One tool that I recommend every modeler have in his/her arsenal is a calculator that works in feet, inches, and fractions of an inch. With that instrument, you can key in 27' 14 7/16", and divide it by 72 to get 2 7/16", without bothering to convert decimals to fractions. Or, if you like, you can work the whole problem on the metric system. The calculator I use for that purpose is a Radio Shack "Decimal Yard-Foot-Inch calculator" that I bought for $35 about 25 years ago, and still works as good as new. (I gave one like it to my father, an architect, for Christmas; he thought he was in seventh heaven, having spent decades converting decimals to fractions in his head.) Nowadays you can pick up a perfectly good one for less than $10 at Lowe's or even Wal-Mart.

Hope that helps.

Yep,got one of those. Made for the construction industry but works in fractions and metric ,very handy

the way to enlarge or reduce drawings that don't fit on your glass is to use "hash marks",,,,,they function almost the same as the registration marks on your decal sheets.

you draw sets of these on the outside of your drawing, say a 1/2 inch from the outside of a flight deck on a carrier

+

+

when you enlarge, you get some overlap so that your crosses show up on both pieces of paper

to assemble the drawing, you just trim both pages with a little of the drawing sticking out past the crosses, and line up the crosses and glue/tape the pages together

Rex

edit to ps,,,,,,,,if you enlarge drawings, it becomes even more important to use the "center of the line rule",,,,,,since you just changed the thickness of the lines and if you use the whole drawing you will be building to a different scale than you intended

I usually find myself reducing drawings. In that case,obviously, the lines on the copy are finer than those on the original. The trade off is that, at least with a home printer/copier, the copy won't be as clear.

You can, for instance, reduce all the drawings in an "Anatomy of the Ship" book to 1/700 scale. (You'll have to do it in several steps.) Those reductions won't be as pear as the originals, but the proportions will be right. I find such reductions extremely useful.

The hard part is finding good scale drawings. In the olden days (thirtys, forties, and fifties) scale model magazines used to publish scale drawings in every issue (not plans for a model, but actual scale drawings of actual aircraft).  Now, it is extremely rare for a mag to do that.  However, some of the plans from the old model mags have been reprinted from them.  Probably the most popular are the drawings of Paul Matt.  However, since these were done during and soon after WW2, you won't find contemporary jets in them.  Finding drawings of contemporary planes, either military or civil, is very difficult.  Wikipedia does give dimensions, such as length and span, so you can check these dimensions.

Scale drawings of ships are a bit easier to come by.