scale size

hal

for example a 1:18 represents what size in inches if possible,

Start with a known length and convert to the units you wish to use. 
eg. one foot = twelve inches. one metre = 100cm

Divide by the scale.

12/18 = 0.6666 inches = one foot @ 1/18th scale

In metric,

100/18 = 5.555 cm = one metre @ 1/18th scale

hi phil, therefore if i use as an example my 1/32 scale corsair it is 323mm lenght and 390 width. which translates to roughly 11.81 inches x 15inches .

1:18 scale becomes much larger in size roughly 1.8 ft x 2.2 ft .  i used the dimensions from the us army plane F4U corsair, with a 33'4in fuselage and 41' wing span . thankshal

good answer learned something yoday.

Ron

1:18 is an odd scale in fractions of an inch per foot. It falls between 3/8 inch per foot (1:16 scale) and 1/2 inch per foot (1:24 scale).  So it is not ordinarily expressed as N inches per foot.  Scales that have a common fraction of an inch per foot are sometimes called "architectural scales,"  and are multiples of, or even fractions of 1/12 or 1/8 inches per foot.  1:18 is not an architectural scale. 

To give you a comparison between 1:48 and 1:18