Righto you lot, spend two days away from pprune and look what happens.
Facts.
TEL does only one thing, Creamie is 100% correct. End of discussion.
Leadsled,
That FAA tests proved no change as described by Deacon, (you are a lawyer) didn't disprove the problem with exhaust valves and seats, because there is no information about the material used in the valves and valve seats of the "test" engines.
TCM and Lycoming have ALWAYS used hardened seats. The problems that started the old wives tales you are reciting stem back to the days when Ag operators in the USA were suffering fuel prices going up and up, they went to UL fuel, and before long they were having problems, so they correctly aligned the sudden spike in valve problems with running unleaded fuel. Therefore the LEAD was protecting the valves. This was a
100% correct OBSERVATION and a
100% incorrect CAUSATION.
The issue was the LATENCY of the fuel. Nothing more and nothing less. The solution was knock off a few degrees of timing and all was good again, happily burning bog standard unleaded.
Now the old Holden engines, they had what? Cast Iron heads and the valve seats were machined into the heads, they were not the fancy seats used in modern engines or the same kind that were used for decades in Aviation Piston engines. Big difference. So the lack of Octane rating and thus the difference in latency mean the peak pressure happens at a different interval, and you should see the results on the Dyno when sampling ICP's at 50khz.
You can come see this in Sydney in November if you like. We do several runs, and we use Mogas ordinary premium unleaded.
Basically as best I can tell from scanning Creamie's posts is his are the only ones 100% correct so far.
Not bad for a dumbs lawyer
So, lets just move onto the bottom line, a 100% drop in replacement for Leaded Avgas. It needs to be unleaded, it needs to be suitable not just for low compression O-320's but also High compression turbo charged engines, and even more so, those on big blowers, C414's, 421's Chieftans and Nevergo's etc.
It also needs to be 100% mixable as the fleet and the fuel outlets need to "change over" without penalty. It also must be compatible with not only new materials but old in service materials.
It must have equal or better vapour pressure properties.
It must also be able to be produced in most decent refineries with no significant cost increase.
I only know of one of these fuels anywhere in the world, having given in the taste test so to speak, seen the data test reports and watched it in action on a TN IO550, I can tell you it is the answer.
It is ready now, just needs some more time for paperwork and an industry to take it up when the FAA give the FLEET WIDE STC approval.
Hows that sound.
Ohh and by the way all those big old radials can have the Hi-Blower unleashed again on this stuff. It out-performs 100LL and the old purple stuff you might remember Leadslead.
Here is the data sheet.
