ARF size labelling
 

Recently I have come across a few ARFs labelled as .25 size (and other engine sizes) only to find after looking at them closely that they are made for exclusively for electric power. A lot of work would be needed to convert them to glow. I find this to be a bit misleading. Some time ago, electrics used to be labelled as 'speed 400 size" or "speed 600" as well as a suitable number of cells, but I guess with all the brushless motors and Li-Po batteries available and no standardisation within the industry, it's just easier to call a plane by the equivalent size of glow engine that would fly it.
I've read a few posts regarding electric setups and I just can't follow all the numbers. It seems that people specify a particular brand and model of motor, type and number and capacity of cells in the battery, capacity of the speed controller and prop size. Given all the possible combinations of these components available, I can see why they call it a .25 size.

RE: ARF size labelling
 

I'm not sure which ARFs you are referring to. I know Eflite has some ARFs that are labelled "25e" and even just "25" (in the case of the J-3 Cub). I admit that may be little confusing, but then Eflite only makes electric planes! They use the 25 and 32 numbers because they have outrunner motors with these designations, which indicates they are meant to replace .25 and .32 nitro power plants respectively.

RE: ARF size labelling
 

It's not really the manufacturers, but more the retailers doing their own write-ups. Here's one example of what I am talking about.....


"Brand New, very adorable 15-25 class Cap 232 which reproduces the full- scale aircraft with amazing accuracy, using precise CAD engineering and data from original Cap 232. New state of the art in highly detailed balsa skin ARF's"

On closer inspection, there was no way anyone would mount a .25 on the thing. It had been designed exclusively for e power.

As I said, it's just one example. I'm not sure who the manufacturer is, and it doesn't really matter, but I'm coming across it more and more.