Re:Did removing lead from petrol spark a decline in crime?
by sokoloff on Tuesday April 22, 2014 @10:43PM
(#7631786)
The problem is that many engines can't be retrofitted to work on (premium autogas) unleaded gasoline.
Most normally aspirated engines will work fine (in some cases, better) on a high grade unleaded auto gas.
Most turbo-charged engines lack sufficient detonation margin when run with that "premium" auto fuel, and need some form of octane boost to provide adequate detonation margins for a high-temp, max performance takeoff run. Several groups, including Swift, GAMI, and Shell, are working on drop-in zero-lead replacements for 100LL. All are flying the fuel in experimental applications as I understand it. None appear "close" to certification.
The real problem is that the bulk of gallons burned are burned by airplanes that are turbo-charged. So, even if 75% of the engines can be readily converted (in many cases, a paperwork-only STC), those 75% of airplanes likely represent fewer than 25% of the gallons burned.
I've been to GAMI in Ada, OK and seen them run their no-lead fuel in a lab setup. It's impressive and looks like it would work. They still face a steep and long uphill battle with the FAA, as do Swift, Shell and the others...
Most normally aspirated engines will work fine (in some cases, better) on a high grade unleaded auto gas.
Most turbo-charged engines lack sufficient detonation margin when run with that "premium" auto fuel, and need some form of octane boost to provide adequate detonation margins for a high-temp, max performance takeoff run. Several groups, including Swift, GAMI, and Shell, are working on drop-in zero-lead replacements for 100LL. All are flying the fuel in experimental applications as I understand it. None appear "close" to certification.
The real problem is that the bulk of gallons burned are burned by airplanes that are turbo-charged. So, even if 75% of the engines can be readily converted (in many cases, a paperwork-only STC), those 75% of airplanes likely represent fewer than 25% of the gallons burned.
I've been to GAMI in Ada, OK and seen them run their no-lead fuel in a lab setup. It's impressive and looks like it would work. They still face a steep and long uphill battle with the FAA, as do Swift, Shell and the others...