what is the difference btwn a helicopter radio and a plane radio

Many radios can do both, or have a "Plane" mode and a "Heli" mode on the same radio. Heli's tend to require more channels - many basic planes are ok with 4 channel radios whereas most heli's require a 6 channel radio.

That's about all I know

The heli radios also have a smoother ratchet on the throttle. I like it better. The mix functions in some of the better radios are far superior as well as the programmable curves.

Newer Heli radios will have CCPM. If your helicopter is CCPM it can not be flown with out it. Also, pots and switches may be configured better for adjustments on hovering trims. Also gyro programming, etc. I also prefer the smooth throttle ratchet. I like it better for planes too.

I like the JR 8103. My suggestion to any on buying a JR radio: If you fly planes and helis, buy a heli radio. It is easier to fly airplanes with the heli radio than helis with the aircraft radio.

Other manufacturers have good Heli radios that are competitive for price and features. All the manufacturers are making good products, so it is just a matter of preference as to brand.