How does one go about determining the correct size electric motor for a plane listed in glow size.
is there a chart or guide available? Please help, thanks.

Richard its not easy as firstly, most motor manufacturers use different codes for the size and then there is also KV involved. The new China codes like 3536, 4250 are most consistent from most China branded motors. Then you have AXI with its own coding. Best to ask around if you are new and soon you will get the hang of it. The EFlite motors use engine sizes and that is great.

Here is a good instructional article that might help you determine motor set ups for specific applications;

http://www.richvalleyrc.com/images/T...ft_Systems.pdf

Also, here is a good calculator to determine overall performance of a specific motor/prop/ESCE/battery configuration:

http://brantuas.com/ezcalc/dma1.asp

There is a lot to learn when first getting involved in electric flight. But, once you follow some of these suggestions, nothing beats actual experimentation with actual observations using your own set ups.

I use a wattmeter whenever I get a new plane, motor, ESC or battery to make sure I don't exceed any of the manufacturers specifications. The one I use comes with an excellent write up on theory and how the wattmeter can be used. Here it is:

http://www.trextuning.com/wattsup.php

Hope all of this helps you out.

Don't get all hung up in the number codes. They don't mean anything useful with regards to motor selection. The exception is Eflite once you get up into the Power 10 and larger motors.

The nice thing is that all the manufacturers are pretty much making the same motors for the most part. You can take the size, weight, and Kv off an Eflite Power XX series motor and use that info to find a comparable motor from another manufacturer.

I have 5000mAh Lipoly 22.2V ( 836 gram) battery, Turnigy C50-65-400 motor ( 460 gram) and 80A ESC. What size aerobatic Yak 54 plane I can use these battery and motor. I built with them Yak 54- 52" wingspan, wing area 511 sq in. or 33 sq dm. and crushed it because wingloading was about 110 gram/sq. dm . So, it was too heavy ( . The flying weght was higher than 2800 gram required for the plan. It was about 3500 gram. It flew like a rocket on full throttle but it was very hard to control. So, it flew out from me. Can anyone tell me any brand Yak 54 for the listed battery and motor that left after the crush? Can anyone help me with this???? I like Yak -54

jmir - Thanks for posting those web sites ... I am saving them for furture use ... well written!
leo