Along the lines of Murphy's Law, I have finally assembled an ARF Brodak Electric Super Clown which I have had in the  queue for a couple of years now. Being essentially cheap I chose not to buy Brodak's overpriced electric component set. What bumped the SC down the queue is that it is setup for the battery to be inserted into a slot in the wing. When I started looking for batteries to fit in the wing slot I found the virtually all 4S batteries were too "fat" to fit so I defaulted to 3S and still most would not fit. Then I happened up on 3S 1800 mah batteries listed on Hobby King USA warehouse that sounded like them would fit fine at $12.53 each! I bought a couple and a motor with a 1300 kv and put the S Clown together. Charged the batteries and gave it a test using a CC Phoenix ESC in Governor High. Wow, I could not get the RPM up and it quickly dropped the battery to 10 volts or so.    I tried a different ESC - same results. I was considering sending the batteries back to Hobby King when I discovered that they were NOT LIpo batteries but really they are LiFe batteries (also called A123 batteries) and 9.9 volts is the nominal voltage for them. Since the ESC was programmed for Lipo batteries it expected to see 4.18 V or so per cell instead of the 3.6 V which is full charge for LiFe batteries. I reprogrammed the ESC and Whee the RPM came up to snuff and the S Clown flies great. I am really surprised that LiFe batteries are selling so inexpensively and in that configuration.  http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=23681  One nice thing about LiFe batteries is that they are not supposed to care if they are stored at full charge and one does not have to mess with discharging them to 50% for storage. A disadvantage is that you pay a weight penalty but for a sport model like the E Super Clown that does not matter too much.

Luckily, the batteries seem none the worse for being charged as Lipo instead of LiFe variety. When searching for batteries I was concentrating on dimensions but you may be sure that I will read ALL the Specs closely from now on!!

Someone who really knows, please check my info, but i understand that the LiFe batteries can be completely discharged rather than needing a 20% margin, so there is actually no weight penalty.

Yes Larry, I believe that is correct but I do not know how much the voltage tails off during that last 20%.

Like you say, someone that has data for the voltage curve for LiFe batteries please chime in.