Andy RR
I had the good fortune to attend a GAMI forum with George Braly in Oshkosh on Friday. What TEL does is delay the start of fast burning of fuel at the spark event (thus making peak cylinder pressure occur where it's easier on the engine somewhere after TDC. Peak pressure is lower but occurs where it's mechanically more effective.) It also slows down the start of pinging because it takes a while for the pinging fire to get its act together in the presence of TEL. Once the fire gets going leaded fuel burns just as fast as unleaded. It's similar to burning large green wood piles. They take a bit to get going but once they do they burn hot and fast. This slow start is called "latency"
JABBA
Same forum. G100 UL is now approved as a drop-in fuel for all aircraft using 100 LL. Now all they need is for someone to start making it. Probable scenario is a state by state roll out. Greens or Govt will apply pressure and a state, perhaps California will outlaw unleaded. Before whenever a push came FAA pulled the safety card and said there was no known replacement. Well now there is.
All
I've seen the best and the worst over here. Innovation and lateral thinking in aviation everywhere. (They are too numerous list here.)
I've also seen Australia under Tony Abbot . The richest country in the world has beggars in the street (many ex military), a v--e--r--y s--l--o--w internet and in some populous places non existant and a crap hospital system. The wages are very low for people in semi and unskilled jobs and the unions have been legislated almost out of existence so there is no effective voice to fight unfair practices.
On a brighter note the Americans we've met have been very friendly and helpful.
Cheers RA