'Unleaded' For G/A..??
Thread Starter
'Unleaded' For G/A..??
From Avweb (USA).....
"Lycoming Pushing For Unleaded AVgas
Moving the general aviation fleet off of 100LL and onto an unleaded fuel will bring positive changes and features to powerplants that pilots will want, Lycoming's Michael Kraft said Wednesday at AirVenture. The company says moving from leaded fuel would unlock the full feature set of its iE-2 FADEC engine for the GA market in part because leaded fuels contaminate certain FADEC sensors (octane, for example) "immediately." If that potential could be unlocked, said Kraft, Lycoming's full FADEC would be more advanced than turbine or automotive engines. Read More
Will the 'metalurgy' of our engines take to this OK..??
'Additives' required..??
Cheers
"Lycoming Pushing For Unleaded AVgas
Moving the general aviation fleet off of 100LL and onto an unleaded fuel will bring positive changes and features to powerplants that pilots will want, Lycoming's Michael Kraft said Wednesday at AirVenture. The company says moving from leaded fuel would unlock the full feature set of its iE-2 FADEC engine for the GA market in part because leaded fuels contaminate certain FADEC sensors (octane, for example) "immediately." If that potential could be unlocked, said Kraft, Lycoming's full FADEC would be more advanced than turbine or automotive engines. Read More
Will the 'metalurgy' of our engines take to this OK..??
'Additives' required..??
Cheers
Creamie,
I will chime in and and say that tetra-ethyl lead performs a number of functions, one of which is the raise the octane rating.
I am told that Continental (possibly Lycoming, anybody know for certain??) have been producing cylinder kits where the specification of the exhaust valve and valve seat have been changed to prevent accelerated damage to same,( ie; using unleaded in an engine designed for leaded fuel) so that unleaded fuel can be used, if you have a "mogas" STC for your aircraft.
There are quite a few engines that were certified originally for 80/87, I have a pair that were originally certified for the little known 92, with suitable valve/seat changes, these should be able to operate on (motor octane number) 100 unleaded.
All the early Gipsy engines had a wonderful fuel specification:" a good grade of motor spirit, well filtered", back in the days when "hi-octane" meant 60.
Tootle pip!!
I will chime in and and say that tetra-ethyl lead performs a number of functions, one of which is the raise the octane rating.
I am told that Continental (possibly Lycoming, anybody know for certain??) have been producing cylinder kits where the specification of the exhaust valve and valve seat have been changed to prevent accelerated damage to same,( ie; using unleaded in an engine designed for leaded fuel) so that unleaded fuel can be used, if you have a "mogas" STC for your aircraft.
There are quite a few engines that were certified originally for 80/87, I have a pair that were originally certified for the little known 92, with suitable valve/seat changes, these should be able to operate on (motor octane number) 100 unleaded.
All the early Gipsy engines had a wonderful fuel specification:" a good grade of motor spirit, well filtered", back in the days when "hi-octane" meant 60.
Tootle pip!!
Lead is there to perform one function, and it performs one function, alone: to reduce the speed of combustion.
Last edited by Creampuff; 2nd Aug 2013 at 04:51.
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on my O-200 it provides two functions.
the one as you mention and as a visual guide to the mixture.
white exhaust too lean, light grey perfect, dark grey to black too rich.
my O-200 runs ok on 91 octane unleaded. dont notice the reduction in power at all.
the one as you mention and as a visual guide to the mixture.
white exhaust too lean, light grey perfect, dark grey to black too rich.
my O-200 runs ok on 91 octane unleaded. dont notice the reduction in power at all.
So the difference in colour is caused by a difference in the amount of lead burnt at the different mixture settings?
Wow: We may have discovered a new OWT!
Wow: We may have discovered a new OWT!
Last edited by Creampuff; 2nd Aug 2013 at 05:44.
Creamie,
I've just learned something new, I didn't need to modify all those Jag cylinder heads to run on unleaded, and the blokes who supplied the new valve seats and valves (of clearly different material to older exhaust valves) was obviously deluded by Jaguar supplying these new p/ns for "unleaded" conversion.
It was all a big con!!
Likewise, those very real examples of "hammered" valve seats I have seen are nothing to do with running unleaded, but the problem mysteriously does not reoccur if we modify the cylinder heads with the new exhaust valves and valve seats.
From a BP data sheet.
UNLEADED WILL NOT HARM YOUR ENGINE
Unleaded Petrol is perfectly suitable for those engines capable of converting from Leaded to Unleaded. These engines do not require lead for exhaust valve seat lubrication and are satisfied by the lower octane of Regular Unleaded Petrol. Old leaded engines not on this list either require lead for valve seat lubrication or require a higher octane fuel.
https://www.google.com/url?sa=t&rct=...3,d.dGIhttp://
Another con job by the RACQ:
Unleaded Petrol and Pre-1986 Cars | Motoring | RACQ
Now, perhaps, we could start a discussion on flame propagation rates of burning, versus pre-ignition versus detonation and the significance of differing octane ratings, and the contributions of various components of the typical leaded and unleaded fuels, and the effects of different fuel air ratios. (ie What does 100/130 for an aviation fuel mean).
Oh Boy, this takes me right back to the test engine for determining octane ratings we had in the basement of the old Engineering School at Sydney Uni. --- that WAS a long tome ago --- but, mysteriously, the ASTM D 910 Aviation Gasoline specification for leaded, of the present day, looks remarkably like the one we had then??
Tootle pip!!
I've just learned something new, I didn't need to modify all those Jag cylinder heads to run on unleaded, and the blokes who supplied the new valve seats and valves (of clearly different material to older exhaust valves) was obviously deluded by Jaguar supplying these new p/ns for "unleaded" conversion.
It was all a big con!!
Likewise, those very real examples of "hammered" valve seats I have seen are nothing to do with running unleaded, but the problem mysteriously does not reoccur if we modify the cylinder heads with the new exhaust valves and valve seats.
From a BP data sheet.
UNLEADED WILL NOT HARM YOUR ENGINE
Unleaded Petrol is perfectly suitable for those engines capable of converting from Leaded to Unleaded. These engines do not require lead for exhaust valve seat lubrication and are satisfied by the lower octane of Regular Unleaded Petrol. Old leaded engines not on this list either require lead for valve seat lubrication or require a higher octane fuel.
https://www.google.com/url?sa=t&rct=...3,d.dGIhttp://
Another con job by the RACQ:
Unleaded Petrol and Pre-1986 Cars | Motoring | RACQ
Now, perhaps, we could start a discussion on flame propagation rates of burning, versus pre-ignition versus detonation and the significance of differing octane ratings, and the contributions of various components of the typical leaded and unleaded fuels, and the effects of different fuel air ratios. (ie What does 100/130 for an aviation fuel mean).
Oh Boy, this takes me right back to the test engine for determining octane ratings we had in the basement of the old Engineering School at Sydney Uni. --- that WAS a long tome ago --- but, mysteriously, the ASTM D 910 Aviation Gasoline specification for leaded, of the present day, looks remarkably like the one we had then??
Tootle pip!!
Last edited by LeadSled; 2nd Aug 2013 at 06:28.
Yes: It was indeed, and continues to be, all a big con.
From the inestimable John Deakin’s must-read article: Lead in the Hogwash http://www.avweb.com/news/pelican/182149-1.html:
From the inestimable John Deakin’s must-read article: Lead in the Hogwash http://www.avweb.com/news/pelican/182149-1.html:
First, a few of the OWTs...
Lead Myths
•Lead does NOT "cushion" or "lubricate" valves. There is nothing in the serious literature, and no known scientific data to support this notion. If you know of something, please write. I said DATA, not some mechanic or overhauler mouthing this decades-old gossip. Remember, EVERYONE once "knew" the world was flat (and some still believe it). I do have one report that high-output marine engines had some valve problems when switched from mogas to unleaded fuels, but that same report said that hardened valve seats took care of that problem.
•Lead has no effect on the BTUs or "power" in the fuel. "Octane rating" has very little effect on BTUs or "power," and what effect it has is in the wrong direction. The more the fuel components are processed to raise the octane, the less "power" the fuel will produce. But the effect is almost negligible. The same "power" is generated by a gallon of 80/87, 91/96, 100LL, or the old 115/145, with or without lead. (What DOES change is the required timing for different fuels. Hold that thought. Timing is that all-important measure of when the spark lights off in relation to top-dead-center piston position.)
•Lead does NOT cause valves to run cooler or hotter. Lead does NOT prevent (or cause) "valve recession."
•Finally, EGT has little or no effect on valve temperature. Most of the heat comes from the very high combustion temperatures during the combustion event, 3,000 degrees Fahrenheit or more, and most of that heat is transferred to the cylinder, and the cooling fins. EGT shows the temperature of exhaust gas after the exhaust valve opens, by which time a great deal of the heat has been dissipated.
I know of NO known reliable DATA to support any of these notions, other than the well-meaning folks who happen to believe them, having heard them repeated over and over for decades. As I mentioned, there is some good data that refutes them, if you'll look.
Just for one example, the FAA ran a twin with flat sixes for several hundred hours, one engine running 100LL, and the other side with unleaded fuel. Then they tore both engines down and used some custom-built instrumentation to measure the valve wear. The lead did no good, at all. That's pretty good data, but I'd like to see more of it. Well done, FAA!
If any of you have scientific evidence for any of these, PLEASE point it out. I am NOT talking about "My mechanic says," or "everyone knows," I'm talking about published, scientific data by reputable people, who know what they're talking about.
At this point, let me point out that in the 30s and 40s, all the best and the brightest engineers were working with recips, and virtually everything we know about them comes from that era. Those people were ENGINEERS in the classic mold, and knew their stuff. What they did with primitive tools is astounding, and just about everything we're re-learning today was known then! Starting in the 50s, all the "best and brightest" gravitated to turbines, and it wasn't long before the general attitude was, "recips are dead." The old knowledge and "corporate memory" died, the marketing folks took over at Lycoming and Continental, and today we see the results. There may be a few real engineers left, but I don't see much evidence of that at the factories. The result is that most technical information coming from "the big two" is either intellectually dishonest, or solidly based on pure ignorance. There is NO curiosity left, and warranties are often worthless. The basic engines are usually excellent, having been originally designed by the engineers of yesteryear, but what the factories have done to them is pathetic.
…
If lead doesn't add power, what does it do? Like "octane," lead ALLOWS a higher power SETTING without detonation. The primary means of accomplishing this is in simply reducing the speed of combustion. By reducing the speed of the flame front, it takes longer to reach maximum pressure, and thus that max pressure occurs later, after top dead center. Can you spell T-I-M-I-N-G, again? …
Lead Myths
•Lead does NOT "cushion" or "lubricate" valves. There is nothing in the serious literature, and no known scientific data to support this notion. If you know of something, please write. I said DATA, not some mechanic or overhauler mouthing this decades-old gossip. Remember, EVERYONE once "knew" the world was flat (and some still believe it). I do have one report that high-output marine engines had some valve problems when switched from mogas to unleaded fuels, but that same report said that hardened valve seats took care of that problem.
•Lead has no effect on the BTUs or "power" in the fuel. "Octane rating" has very little effect on BTUs or "power," and what effect it has is in the wrong direction. The more the fuel components are processed to raise the octane, the less "power" the fuel will produce. But the effect is almost negligible. The same "power" is generated by a gallon of 80/87, 91/96, 100LL, or the old 115/145, with or without lead. (What DOES change is the required timing for different fuels. Hold that thought. Timing is that all-important measure of when the spark lights off in relation to top-dead-center piston position.)
•Lead does NOT cause valves to run cooler or hotter. Lead does NOT prevent (or cause) "valve recession."
•Finally, EGT has little or no effect on valve temperature. Most of the heat comes from the very high combustion temperatures during the combustion event, 3,000 degrees Fahrenheit or more, and most of that heat is transferred to the cylinder, and the cooling fins. EGT shows the temperature of exhaust gas after the exhaust valve opens, by which time a great deal of the heat has been dissipated.
I know of NO known reliable DATA to support any of these notions, other than the well-meaning folks who happen to believe them, having heard them repeated over and over for decades. As I mentioned, there is some good data that refutes them, if you'll look.
Just for one example, the FAA ran a twin with flat sixes for several hundred hours, one engine running 100LL, and the other side with unleaded fuel. Then they tore both engines down and used some custom-built instrumentation to measure the valve wear. The lead did no good, at all. That's pretty good data, but I'd like to see more of it. Well done, FAA!
If any of you have scientific evidence for any of these, PLEASE point it out. I am NOT talking about "My mechanic says," or "everyone knows," I'm talking about published, scientific data by reputable people, who know what they're talking about.
At this point, let me point out that in the 30s and 40s, all the best and the brightest engineers were working with recips, and virtually everything we know about them comes from that era. Those people were ENGINEERS in the classic mold, and knew their stuff. What they did with primitive tools is astounding, and just about everything we're re-learning today was known then! Starting in the 50s, all the "best and brightest" gravitated to turbines, and it wasn't long before the general attitude was, "recips are dead." The old knowledge and "corporate memory" died, the marketing folks took over at Lycoming and Continental, and today we see the results. There may be a few real engineers left, but I don't see much evidence of that at the factories. The result is that most technical information coming from "the big two" is either intellectually dishonest, or solidly based on pure ignorance. There is NO curiosity left, and warranties are often worthless. The basic engines are usually excellent, having been originally designed by the engineers of yesteryear, but what the factories have done to them is pathetic.
…
If lead doesn't add power, what does it do? Like "octane," lead ALLOWS a higher power SETTING without detonation. The primary means of accomplishing this is in simply reducing the speed of combustion. By reducing the speed of the flame front, it takes longer to reach maximum pressure, and thus that max pressure occurs later, after top dead center. Can you spell T-I-M-I-N-G, again? …
Last edited by Creampuff; 2nd Aug 2013 at 06:25.
Creamie,
I have the greatest of respect for John Deacon, but nobody is always correct about everything, unless you want to believe that "big oil" and "big auto" ran a con job on exhaust valves world wide.
What would the motive have been, unleaded was a done deal. Why would OEMs now be offering cylinder kits "suitable" for unleaded, if any of the P/Ns could run on unleaded for a normal overhaul life --- another big con job???
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.
I have considerable experience with "old" auto engines, particularly Jaguar XK series --- it is quite remarkable how rapidly old material seats "hammered" or recessed withing a few thousand miles with unleaded. Equally, such problems ceased when we rebuilt heads with Jaguar supplied replacement seats and valves.
Old Holden "grey" motors were a particular problem, the early "Holden" 5L and the 350 Chev derived engines of the era also suffered, even with "lead substitute" additives.
This isn't my imagination, it is all a matter of records.
Tootle pip!!
I have the greatest of respect for John Deacon, but nobody is always correct about everything, unless you want to believe that "big oil" and "big auto" ran a con job on exhaust valves world wide.
What would the motive have been, unleaded was a done deal. Why would OEMs now be offering cylinder kits "suitable" for unleaded, if any of the P/Ns could run on unleaded for a normal overhaul life --- another big con job???
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.
I have considerable experience with "old" auto engines, particularly Jaguar XK series --- it is quite remarkable how rapidly old material seats "hammered" or recessed withing a few thousand miles with unleaded. Equally, such problems ceased when we rebuilt heads with Jaguar supplied replacement seats and valves.
Old Holden "grey" motors were a particular problem, the early "Holden" 5L and the 350 Chev derived engines of the era also suffered, even with "lead substitute" additives.
This isn't my imagination, it is all a matter of records.
Tootle pip!!
Last edited by LeadSled; 2nd Aug 2013 at 06:47.
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TetraEthyl Lead was determined by experimentation as the best of 16,000 substances tried as a detonation inhibitor. it was significantly better than the next best substance.
described in "Engines & Enterprise, the life and work of Sir Harry Ricardo" by John Reynolds. published by Haynes Publishing as book H4516.
ISBN 978 1 84425 516 0
Library of Congress card No. 2008922573
a very interesting read.
"moreover, in 1926 two scientists working for General Motors in the USA, Charles Kettering and Thomas Midgeley, discovered the use of tetraethyl lead as an additive had a remarkable effect in reducing the tendency of petroleum fuels to detonate"
described in "Engines & Enterprise, the life and work of Sir Harry Ricardo" by John Reynolds. published by Haynes Publishing as book H4516.
ISBN 978 1 84425 516 0
Library of Congress card No. 2008922573
a very interesting read.
"moreover, in 1926 two scientists working for General Motors in the USA, Charles Kettering and Thomas Midgeley, discovered the use of tetraethyl lead as an additive had a remarkable effect in reducing the tendency of petroleum fuels to detonate"
Last edited by dubbleyew eight; 2nd Aug 2013 at 06:51.
dubbleyew8,
An equally good read:
"I Kept No Diary" by Air Commodore Rod Banks.
Banks was an Australian who was the youngest naval commander in WW1 -- of an armed sand barge patrolling the Suez Canal.
During the 20s/30s he worked for International Octel Inc, who "invented" Tetra Ethyl Lead as a petrol additive, selling it around Europe. He became a fuel expert, and was responsible for the "bug juice"mixtures used in a number of Schneider Trophy contenders, particularly Italian and British.
That was all about octane ratings, whatever the additives, the wear reduction properties of "lead" were a useful side effect.
By WW11, he was called up, in the RAF, worked for Beaverbrooke, and played a central role in making one single gasoline the standard for everything gasoline before D-Day.
There is a very interesting story of an airlift of valves from US to UK in the weeks before D-Day, it was found that a lot of British MT was not compatible with the available petrol, thousands of vehicles had to have new valves fitted -- one GMC has valves of the right stem diameter, wrong head, so there was a frantic effort to re-machine the heads to the right size and fit them before D-Day. Maybe a bit off thread, but all about compatibility of materials and fuels.
Tootle pip!!
An equally good read:
"I Kept No Diary" by Air Commodore Rod Banks.
Banks was an Australian who was the youngest naval commander in WW1 -- of an armed sand barge patrolling the Suez Canal.
During the 20s/30s he worked for International Octel Inc, who "invented" Tetra Ethyl Lead as a petrol additive, selling it around Europe. He became a fuel expert, and was responsible for the "bug juice"mixtures used in a number of Schneider Trophy contenders, particularly Italian and British.
That was all about octane ratings, whatever the additives, the wear reduction properties of "lead" were a useful side effect.
By WW11, he was called up, in the RAF, worked for Beaverbrooke, and played a central role in making one single gasoline the standard for everything gasoline before D-Day.
There is a very interesting story of an airlift of valves from US to UK in the weeks before D-Day, it was found that a lot of British MT was not compatible with the available petrol, thousands of vehicles had to have new valves fitted -- one GMC has valves of the right stem diameter, wrong head, so there was a frantic effort to re-machine the heads to the right size and fit them before D-Day. Maybe a bit off thread, but all about compatibility of materials and fuels.
Tootle pip!!
Last edited by LeadSled; 2nd Aug 2013 at 07:33.
......where's JABBA?
Come on Jabba we won't bite:-)
He'll set us all straight, that guy knows way too much about recip donks
Lead is a good lubricant, used on door hinges as well:-)
Wmk2
Come on Jabba we won't bite:-)
He'll set us all straight, that guy knows way too much about recip donks
Lead is a good lubricant, used on door hinges as well:-)
Wmk2
Creampuff, are you actually aware that valves rotate slowly as they work (otherwise you could make them square, triangular or any other shape you like that would increase valve seat area to get more charge in and out), which is one of the reasons they need some form of deposit regularly being put on the valve face or it will dig itself into the valve seat as there is nothing to stop complete metal to metal contact and galling from the rotating valve as it closes. BTW, your link is broken/not copied correctly and I suspect they would ignore this one small fact as it doesn't suit their argument.
You may wish to expand your understanding further with this from Shell: Avgas Facts and Future which touches on a couple of reasons why some older designed engines will not cope with unleaded fuels that do not have any form of additive in them that protects the valves and their very soft seats. This issue does not affect ALL engines, just a few with certain composition seat inserts.
I respect your superior intellect and intimate knowlege of legal circles and regs etc, however you're well wide of the mark on this one. The last thing I wish to do is enter into a piddling contest but this issue does only effect a small percentage of engines but what it ultimately means is that someone may have to spend $$$$ on designing and certifying new seat inserts that will work well and stay in situ (think expansion rates) - or that will spell the end of the effective life for those engines.
Regards,
OpsN.
You may wish to expand your understanding further with this from Shell: Avgas Facts and Future which touches on a couple of reasons why some older designed engines will not cope with unleaded fuels that do not have any form of additive in them that protects the valves and their very soft seats. This issue does not affect ALL engines, just a few with certain composition seat inserts.
I respect your superior intellect and intimate knowlege of legal circles and regs etc, however you're well wide of the mark on this one. The last thing I wish to do is enter into a piddling contest but this issue does only effect a small percentage of engines but what it ultimately means is that someone may have to spend $$$$ on designing and certifying new seat inserts that will work well and stay in situ (think expansion rates) - or that will spell the end of the effective life for those engines.
Regards,
OpsN.
Last edited by OpsNormal; 2nd Aug 2013 at 07:25.
I don’t understand how you can still get the guy’s name wrong
Easy, and if I recall correctly, this is not the first time I have made that mistake, and you have picked me up. It's all because I have an acquaintance called Deacon. I promise to try harder.
As to data, what data would you like. The problem of exhaust valve seats v. unleaded fuels or not an urban myth. As far as I an concerned, my own personal experience over quite a number of engines is enough for me.
If it really is a huge con. job, it is one of the most successful and enduring of all time. The 1986 lists of vehicles came from the vehicle manufacturer's themselves, on what basis they separated valve/valve seat suitability in various models for unleaded operation without modification I do not know, but I doubt they plucked it out of thin air --- not after their experiences with Ralph Nader.
If all they wanted to do was sell new cars, why did some offer conversion kits of one kind or another (ie: Jaguar selling valves and seats made of the same material as later generation -post mid 1980 - production)
In Australia, NSW DMT/RTA (or their predecessor?) NRMA, RACQ, RVAC etc were all suckered in, amazing!!
Tootle pip!!
Ok.....The solution is.... install hardened valve seats and if you want to go the whole hog...buy a set of stainless valves. In an automotive engine costs about a grand plus labour of remove and replace cylinder head(s).
I can't see why it would be more complicated in an aero engine not counting CASA's involvement.
I can't see why it would be more complicated in an aero engine not counting CASA's involvement.
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CNG
I found this idea interesting,
an old composite oxy bottle and some CNG and off we go, would fit perfect in the belly of a 206
wonder what it will do to temps
what say Jaba?
an old composite oxy bottle and some CNG and off we go, would fit perfect in the belly of a 206
wonder what it will do to temps
what say Jaba?
Last edited by Oracle1; 2nd Aug 2013 at 08:16.
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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,
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.
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.
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.