hoppy

Don't laugh, what does 1/2A actually mean? I've been flying glow engines for almost three years and am working on a Herr Piper cub that is "1/2A". I want to convert to electric, but first I would like to know what size glow engine is used.

flyinrog

My Feedback: (1)

I usually get close on this one, but theres lots of folks that can fix it here A class is .050 and over? .049 is 1/2A .020-.033 is 1/4A and .010 is 1/8A or so you could change from an .049 to an.051 and switch classes from 1/2A to A just by changing out engines on the same plane...Rog

cwrr5

My Feedback: (32)

Would that make up to .25 "AA" and .25 to .50 "AAA"? .50 to 1.20 = "C"? Gas engines = "D"?


Don't take this seriously!!!!!!!!!! I just have a warped sense of humor..
Actually, I always wondered what the designation meant... Thanks guys!

hoppy

Thanks Rog, I guess I wasn't alone.

dennis

My Feedback: (90)

Now what would you do if you were in Merry old England and 1/2 A is an 09?
Dennis

gcb

At one time class A was anything up to .19. From there to .29 was "B", I think thru .40 was "C" and above that "D".
When the .049's (and others near that) came out, they established a class for smaller engines with a limit of .05 (in the USA), and named it 1/2A (even though it was only 1/4A in actuality). There is no OFFICIAL 1/4A and 1/8A as far as I know...it's just a size reference.
Later as more US flyers wanted to compete in FAI FF, the .19 size class "A" fell to the wayside popularity wise in favor of the .15. (FFers can correct me on this.)
There were several engine sizes on the class border. For 1/2A it was .049 and .051. For class A it was .19 and .201, etc.
The purpose was to allow a FF plane to fly in two classes without having to re-trim.

This is all from memory so please keep me honest.

George

Larry Driskill

The engine defined classes are probably only important to folks interested in competition and to others who need some standards to more easily converse so all involved in the conversation are on common ground and speaking the same "language".

The CL Speed section in the AMA Rule Book lists the engine classifications. Look on page four of the Acrobat document.


http://www.modelaircraft.org/PDF-fil...ook/cline1.pdf

Bipe Flyer

I think the classes have been changed a few times and they vary slightly depinding on if you compete in FF, CL etc.

I've seen a few charts with slightly different cutoffs between classes, but I beleive this one is pretty close.

Class Cubic Inches

1/2 A 0.000 to 0.050

A 0.051 to 0.0.1525

B 0.1526 to 0.300

C 0.301 to 0.650

Generally speaking 1/2 is anything around an .049 but we include up ot .09 in discussions here.

As Flyinrog mentioned, although they aren't official classes, people use the terms 1/4A for .020 - 033 and 1/8A for .010.