Sounds like you've done some REAL flyin! I'm pretty low-end at this point, but I'm learning fast. My problem is that I tend to get into something (ie, RC airplanes), learn "just enough" about them, then start doing modifications and upgrades that are out of scope of the original hobby. At least here I'm trying to meld the RC hobby with the PIC/electonics hobby. I'm a mechanical engineer by training, so most of this stuff comes fairly easy (though at the expense of my free time...)

Anyhow, 6-7 cell NiCd batteries were the start of electric R/C, then came NiMh which had better capacities and weight. Now the latest thing is Lithium-Polymer (or LiPo) that has an incredible energy density. The discharge rate isn't as high as the regular batteries, but it's getting better all the time. The other downsides of LiPo's is that you can't overcharge them (they explode) and you can't run them down below 3 volts or you'll damage them - hence my voltage monitor project.

Transmission is at 72MHz for air, and I think it's 75MHz for ground vehicles. Many of the new radios are digital, and in my case, fully programmable as well.

Check out www.rcgroups.com for some great discussion and info on the "state of the art" of electronic flight!

-Jeff