Determine the scale of a model

[OV10]

I don't know how many times that I have seen this question asked across many forums, "Does anyone know the scale of this model?".
I am amazed at how many modelers don't know the simple equation for determining this or maybe it is just a lack of self motivation to figure it out due to the quirks of social media but I would like to believe it is not the latter.
So here is the equation:
(full scale wingspan in feet) x 12 (inches in a foot) / (wingspan of model in inches) = denominator of the fractional scale of 1

Example:
An OV-10 Bronco has a 40' wingspan
This is the model that I want FlightLine to do with a 60" span
40 times 12 = 480 divided by 60 equals 8 which is the denominator of the fractional scale of 1 = 1/8 scale

OK pilots, no excuses for not being able to figure the scale for yourself ;)

[bradl4648]

Hay thinks for bringing this up I get quite a few people call and ask what scale a plane is.

[WintrSol]

Sometimes, you have to use the length, but the math works the same. For example, my E-flite TaylorCraft (46" wingspan) is based on a clipped-wing version, even though the color scheme comes from a stock version. Using the length, the scale is 1:7-1/3, which means the wings were clipped to ~28' (from 36') in the prototype. Or 1/7.333, if you will.

BTW, a typo in the equation, which should be:
(full scale wingspan in feet) x 12 (inches in a foot) / (wingspan of model in inches) = denominator of the fractional scale of 1

[OV10]

BTW, a typo in the equation, which should be:
(full scale wingspan in feet) x 12 (inches in a foot) / (wingspan of model in inches) = denominator of the fractional scale of 1

Fixed.........thanx WS

[Kloverzero]

I did a lot of drawing my own plans for models, especially EDFs that you really couldn't find in the sizes or configuration that I wanted, such as TWO motors in a TWO engine Hornet, etc...and I had to scale them accordingly. I never really cared about what the actual scale was to the plane, but I would take a three view and isolate the intake, figure it to the size of the fan I wanted to use, multiply in mm because it is easier than converting inches, and figure the dimensions of the model. I would then create a center line and extend all of the angles to and out from the center line, and grab the angles with my protractor. It was then a simple task of transferring the angles and measurements to a larger sheet, and creating a center top, and center side view to work off of. I made several successful EDFs this way, and I did an OV-10 as well. The OV was by far the greatest success, and I would probably still be flying it today had an aileron servo not gone berserk on me!!

[4FunRC]

Have I got the math correct?

Formula to equate a model's scale of an airplane/aircraft using wingspan.

Plane's actual wingspan is 99 ft.

99ft x 12in = 1,188

Model's wingspan is 44 in.

1,188 divided by 44 in.
(1188/44) = 27

27 = 1/27th scale

Thanks!

[OV10]

Hello 4FunRC and welcome to the Squawk,
Your math is spot on ;)

[Grossman56]

Every once in a while, a post like this comes along that really helps everyone here, and the funny thing, it's usually Warbird Charlie that posts it!!
Thanks again fro the great info Charlie!!

Grossman56

[seaviper]

It's interesting to do this with the length of the fuselage as well. Often the scale of the fuselage will not be the same as that of the wing.

[OV10]

It's interesting to do this with the length of the fuselage as well. Often the scale of the fuselage will not be the same as that of the wing.

Correct, but only in regards to clipped wing aircraft as noted by WintrSol in post#3

[seaviper]

Nope. Manufacturers often have the scale of the fuse different than the scale of the wing. Take the Freewing Me-262. The wingspan is 1:8.27 while the fuselage length is 1:8.44. Almost every scale RC plane has differences in scale dimensions all over the aircraft. This is due to mfg limitations, how you want the bird to fly, what kind of equipment is available for servos and motors, etc. The 262 is pretty close in both dimensions. The FMS 1400mm T-28 is 1:8.5 in length, 1:8.7 in wingspan.

[WintrSol]

A couple tenths difference doesn't seem significant, to me. Now, if one was 1:8.5 and the other 1:7, I'd say there was something amiss.

[OV10]

Nope. Manufacturers often have the scale of the fuse different than the scale of the wing. Take the Freewing Me-262. The wingspan is 1:8.27 while the fuselage length is 1:8.44. Almost every scale RC plane has differences in scale dimensions all over the aircraft. This is due to mfg limitations, how you want the bird to fly, what kind of equipment is available for servos and motors, etc. The 262 is pretty close in both dimensions. The FMS 1400mm T-28 is 1:8.5 in length, 1:8.7 in wingspan.

Hello seaviper,
You're correct but I don't know that many modelers that are into the tenths of scale nor are aware of wing/fuze disproportions for flyability unless they are an aspiring master scale builder or the scale police. LOL
Your examples of the 262 and T-28 for all intents of scale purpose are still between 1/8 and 1/9 scale birds.(however you prefer to look at it)
Having both the 262 and T-28 myself, I for the most part call them 1/8 because that is the general size I try to associate my fleet sizing to. :)
To the average recreational flyer they do look really good but to the scale perfectionist there is a bunch of stuff that is not..... like pilots for one. ;)

My original posting of this thread was nothing more than to just give the folks an easy way to get a 'general' scale sizing of their model. :Cool:

Best regards,

[benjack71]

Nope. Manufacturers often have the scale of the fuse different than the scale of the wing. Take the Freewing Me-262. The wingspan is 1:8.27 while the fuselage length is 1:8.44. Almost every scale RC plane has differences in scale dimensions all over the aircraft. This is due to mfg limitations, how you want the bird to fly, what kind of equipment is available for servos and motors, etc. The 262 is pretty close in both dimensions. The FMS 1400mm T-28 is 1:8.5 in length, 1:8.7 in wingspan.

You are correct. That is why you have the term "sport" scale applied to models such as Top Flight 60 size war birds. Where a ESM is pretty darn close to scale with fuse and wings. Which is also why they are considered some of the more difficult models to fly. FMS models, at least the 1400 and 1700 stay pretty close to scale with their warbirds as well. Which is why the wing loading on the FMS warbirds is often times higher than comparable other models. Hangar 9 probably has some of the lightest wing loading for a balsa plane, at least the older ones in the 60 size did. Such as the Hellcat, the Corsair and the P-47. They also did not even have flaps because they were light enough you did not need them. Where as Top Flite was more scale with their 60 size balsa, came with flaps and could be a little more difficult to fly IMO.

[benjack71]

I don't know how many times that I have seen this question asked across many forums, "Does anyone know the scale of this model?".
I am amazed at how many modelers don't know the simple equation for determining this or maybe it is just a lack of self motivation to figure it out due to the quirks of social media but I would like to believe it is not the latter.
So here is the equation:
(full scale wingspan in feet) x 12 (inches in a foot) / (wingspan of model in inches) = denominator of the fractional scale of 1

Example:
An OV-10 Bronco has a 40' wingspan
This is the model that I want FlightLine to do with a 60" span
40 times 12 = 480 divided by 60 equals 8 which is the denominator of the fractional scale of 1 = 1/8 scale

OK pilots, no excuses for not being able to figure the scale for yourself ;)

That is some good info. I have it on my phone somewhere, but I always forget it. Thanks fot that post!

[seaviper]

Definitely not the scale police here. I love to fly. I will sacrifice scale for flight performance any day. If you want some good laughs, watch a Top Gun video from back in the day. Beautiful scale birds. Lots of wrecks. I prefer my birds to fly and be fun.
But I am trained as an engineer. so the nerd in me comes out occasionally....

[WintrSol]

Trained engineer here, too, but I worked for a fighter aircraft company, and a few tenths was good enough for government work.LOL

[Stringbag]

Trained engineer here, too, but I worked for a fighter aircraft company, and a few tenths was good enough for government work.LOL

I thought all that was needed for Government work was a Black Suit and OBLIGATORY Dark Sunglasses. And maybe a Black Escalade tossed in the mix.....