What scale am I printing, (a point of curiosity only)

[smp]

I have been printing 1/33 scale files on letter size paper, so the model is smaller than 1/33. (Printer software says 92% of full size)



My math skills have deteriorated from poor to nearly nonexistent. I measured a printed wing, (printed at 92%) at 22 cm and looked up the aircraft specs, (Aviatik Berg D.I), at 8m full size. My math was as follows: 0.22m x Scale = 8m. The scale working out to about 1/36.4 scale. Not that it matters, because I'm still getting 100% fun, but did I come close to getting the numbers right?
TIA
sp

[Draco]

Not all the printers print at the same scale, there are some milimeters of diference depending of the company and model, and the margin configuration.
The simplest solution is to take a rule, to size the distance between wingtips, and divide real size against model. What you did is exactly the real scale

[SCEtoAUX]

Yes, you did the calculations correctly.
Here is a handy little scale calculator you can download:
Starship Modeler - ScaleMaster Scale Calculator

[airdave]

Sounds like you are allowing 'fit to page'.
And this is reducing the printed area to fit within a default page margin.
(with some printer software, you can change the margin widths)

if a model has been designed on Letter size page, it does not need to be scaled to fit.

Why not opt for 'no scaling' or turn off 'fit to page' ?

One problem with fit to page, is that the scale reduction is not consistent across multiple pages.
In fact, unless every page of the model has a repeated frame or border (like I do with my models)
the scale up or down to fit the printed area will change.

So, with a multi page model, you can end up with parts of different scale.
they will be close...but not close enough for an accurate model.
(I always suggest 'no scaling' with my kits)

Also, keep in mind, when checking model scale, that most modellers are not that accurate when designing their models.
These are paper modellers, not NASA draftsmen...and many designs are based on found drawings and plans...not actual factory blueprints.

[Draco]

Dave is right, some modelers aren't "scale sensitives"
One example is Zio Prudenzio, he did a lot of wonderfull planes... but his scale was "to fit the plane in one page". The fighters were roughtly at the same scale... the bomber to another.
What I did when assembling his first planes was to print a test, measure tip to tip, rescale and make the definitive print. Even now I have to gift some plane to my friends when the scale is sligthy off

[smp]

Thanks y'all. Kind of surprised I got the math correct. Doug, I sure appreciate the scale app. Dave, I will be aware now that different pages can be different scales without a border. I have an old printer which can print A4 paper, I haven't used it in years, but I expect I need to dust it off and find some new ink cartridges for it as that would solve all issues. In the mean time, I have been lucky in that all the models I have printed and started have had no badly fitting pieces. My plastic model collection is in 5 different scales, so I'm not that particular, just curious.
Thanks again
sp

[Erik Zwaan]

Hi, I'd say the best thing to do is to ensure you do not choose "fit to page" but use the option of manual scaling and enter 100%. It depends a bit on the printer menu but there's always the option of customizing the scale. Some model sheets show a ruler so after printing you can measure if you have printed the right size.

And of course, if you know the exact dimensions of the original, then you know for sure.

Regards,
Erik

[Lex]

Dave is spot on. The size defined by your setting is only accurate if you print at 100%. Fit to page will result in uncontrollable scaling

[hornswoggler]

Originally Posted by smp

... Kind of surprised I got the math correct. ...
sp

Your practical approach got you 1:36.4. That is pretty close to the theoretical scale.
Here is a refresher on how to calculate the exact scale. This may be of interest because it does not require any specific knowledge (specs) about the prototype.
Consider the following:

If you print out a 1:33 scale kit at 100% then a part that is 1cm on paper represents 33cm (= 1cm x 33) in real life.
If you print out the same kit at 92% then the very same part is only 0.92cm (= 1cm x 92% = 1cm x 92/100) on paper but it still represents 33cm of the prototype.
The printed scale therefore is 0.92:33.
Every scale can be considered a fraction. As we may recall the value of a fraction remains the same when you divide both numerator and denominator by the same number. To convert this "funny" scale into the "standard" form we are more familiar with we divide by 0.92. So, the exact scale is 1:35.9 because (0.92/0.92) : (33/0.92) = 1:35.9

Now, if we round our results we both arrive at the same number 1:36.
Reassuring that theory and practice confirm each other .

This little exercise can be generalized for any combination of kit scale and print settings: kit 1:x, printed at y%, New scale 1:x/y%
Example 1: kit 1:72, printed at 50% New scale 1:(72/50%) = 1:(72/0.50) = 1:144
Example 2: kit 1:200, printed at 150% New scale 1:(200/150%) = 1:(200/1.5) = 1:133

The same scale relationship can be turned around to calculate the print setting necessary to re-scale a kit you have in the "wrong" scale to be printed in your favorite scale.
The original scale is 1:old, the new scale shall be 1:new, then print at old/new

Example: old scale is 1:72, new scale shall be 1:100, print at 72/100 = 0.72 = 72%

Best
Hornswoggler