It’s a story about chemistry, engineering and regulation – many small aircraft owe their heritage to World War II and were designed for high octane fuels which require lead. Why has it taken so long to figure out an alternative, and why are we now facing potentially incompatible fuels in the coming decade.
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"0.56 g/L or 2g/gal but who would use those ridiculous units" 🤣🤣🤣 ridiculous how people still struggle to perform a simple conversion, I remember when I was in grade school and couldn't multiply numbers 🤣 then I grew up and figured out how to perform simple mathematics. 😂
As someone who plays Minecraft with a bunch of complex engineering mods that add oil distillation and chemistry, this is interesting. I always thought that the octane rating was because fuel vendors added different amounts of octane to regular gasoline to make it more stable for higher compression to avoid detonation.
Hi, drivetrain engineer here. I worked for, among others, Ferrari, Porsche and Bentley.
Aircraft engines are mostly hilariously obsolete, because certifying new ones is expensive and also, most of the industry is in the US, where Standards are just lower, engineering know how is lower, standards of available materials is lower and manufacturing standards are loerr.
You could run more power, for a significantly less fuel consumption, on unleaded 98, 100 or 102 octane fuel from an engine if it were built to the Standards of european car engines. DOHC, 4V per cylinder, GDI, much narrower piston clearance and blowby and also modern Combustion cycles and modern forced induction. My Daily driver has an engine that makes any Lycoming or Continental look like a fossile.
The AvGas fuel to airplane engines is a fuel with more possible energy per liter. This is good because the plane can carry more weight. To give 100 octane using tetraetila lead is necessary only 1/2 cm3 ( 0,46 cm3 ) tetraetila led. You can make AvGas 100 octane using MTBE ( metil terciário butil éter) but to get 100 octane is necessary minimum of 10 cm3. As the tetraetila lead have less calories than petroleum the final calories of the blend come to be less than using 0,46 cm3 of tetraetila lead ( and for planes probably this is not so good ). The plane pay loads will be less.
3:23 another chemistry geek here, my OCD can't resist commenting that you forgot Heptane (seven C atoms) in your graph. 😉
This is a topic that really grinds my gears, we have figured out how to get unleaded fuel in vehicles for decades. I can tell you one easy way to get air planes updated to run on non-leaded fuel… stop making leaded fuel, boom done over night they would figure it out.
If your plane cant run on unleaded that's not my problem, and it does not give you a license to poison those that live around small airports.
If you're anywhere near a Wawa most of them have blue pumps. Those blue pumps are ethanol-free and you should be running them in any older vehicles as well as your boats and smaller engines. Ethanol is also hydroscopic so it sucks up water and can cause water buildup in the bowl of small equipment. This means that you're afloat can no longer operate and it will seem like your engine is starving for fuel. I still have an old Blazer I keep running and it runs on ethanol free as well. When I went to school for my a&p license I dealt with 100 LL a good bit. Lead is also used in the fuel as a lubrication so I wonder what their synthetic lubricants might be?
When it comes to fuel I I really do trust VP racing because I've dealt with them for so long. We used to run super late model race cars and VP was the sponsored fuel of the tracks we ran. Even my big 6 gallon race cans are VP race cans
I just chalk it up to incompetence and laziness and go from there
Detonation=crash.
I kinda find it funny – US: 90 Octane gas for the cars, the only other option would be 90 Octane with ethanol. Germany: no 90 Octane fuel at all. Minimum today is 95 Octane, in a variant with up 5% ethanol and one with up to 10% ethanol (Super and Super E10). Other than that, you have Super Plus with 98 Octane and up to 5% ethanol and the more expensive brands started marketing and selling "High Performance Fuel" with 102 Octane (also, <5% Ethanol), name depending on the brand.
With older engines, the higher quality fuels don't do much, since you can't adjust much on the fly. With modern engines with the right sensors, they can detect knocking and adjust things, so for some engines, the 102 Octane fuel is actually more efficient.
The FAA and the Engine Manufacturers don't want to pay the costs to find a universal fuel. I guess one more reason to get a Diamond, and burn jet fuel.
I thought Germans could produce Ethyl and the Americans got something in exchange (wasn't it synthesized rubber?)
Regarding flying other planes – you could look into getting or renting a Diamond DA-40. They have some variants that run on Jet-A and can be certified for Diesel. They are in a similar price range as Cirrus SR-22 but they get incredible endurance. Since the plane was designed for a Lycoming engine, it has the fuel capacity to fly for 3-4 hours with that engine. The Diesel engine (based on a Mercedes-Benz 2.2l engine block) is much more efficient, resulting in an endurance of up to 8 hours.
Former Environmental Regulator here. There are two reasons for the use of tetraethyl lead in gasoline. Both of these reasons are driven by costs: (1) Adding lead to gasoline is a relatively inexpensive way to raise the octane rating of gasoline, thus making it cheaper to produce than refining the fuel differently, which would be more expensive to produce and (2) The lead deposits penetrate into the engine valve seats, providing extra lubrication. In modern car engines, costlier hardened valve seats must be used because the gasoline used no longer contains lead. While leaded automotive gasolines were sold, federal law required a standard warning sticker to be prominently displayed on each dispenser of leaded gasoline.
You can still see these stickers today at our the very few gas stations that also sell racing gasoline because it is exempt from the ban on leaded gasoline because it
is for off road use only. Interestingly, aviation gasoline dispensers have never been required to be labeled as leaded, so you will not see the leaded gasoline labels on aviation gasoline dispensers.
When your conscience says turbine aircraft but your wallet says steam turbine
I thought engine knock occured because of too high internal engine temperature and too quick of a moving piston. The quick compression would detonate the fuel mixture prematurely.
We have "no ethanol, 91octane" at a lot of normal gas stations in mt, usa. I use it in my 1979 F250… CHEERS!
Do you think the Airplane crash in Fullerton CA. Could be relative this the new fuel in San Diego County?
Greetings from KHWD (Hayward, California).
It’s tough to compete with over 3,000 comments on a two day-old video. Good job, Scott! You certainly stirred the pot. Anyway, I have a few thoughts that I would like to share.
I bought my airplane from an owner who parked it at Reid-Hillview in San Jose. It’s currently based in Hayward. It’s a 1975 Bellanca Decathlon with a 180hp Lycoming IO-360 engine. It happily works well on 100LL. Reid-Hillview has a departure procedure that purposely avoids overflying a nearby school. That’s neither here nor there, but it did have a lot to do with them banning the sale of 100LL at the airport. The city of San Jose was equally as concerned about the health of pilots. They banned the sale of candy bars in vending machines at the airport terminal located near transient aircraft parking. Apparently, sugary snacks sold to pilots passing through, are as dangerous as leaded fuel.
I think that the question about lead in aviation fuel is a big giant red herring floated by non-aviation activists who make a bigger deal about aviation leaded fuel exhaust than is really a problem. I don’t have a bunch of statistics in front of me, but the vast majority of single engine, leaded fuel-powered airplanes flying around local airports, belong to, or are leased to flight schools. Look around any small airport and you’ll see airplanes tied down that never seem to move, and rows of hangar doors closed that never seem to open. The average general aviation aircraft used for recreation and non-commercial use, barely scrapes 95 hours per year. Most are used quite a lot less. The average age of a typical general aviation aircraft is over 50 years old. To me, all of this effort and expense to phase out leaded aviation fuel is driven by people with agendas that have nothing to do with promoting aviation. Aircraft operators like me are not polluting the environment when we’re not flying. Our carbon footprint is practically insignificant when we are flying for only an hour or so. My airplane is in a hangar while I’m typing this. An hour or so of aerobatics and/or a few trips around the pattern to keep our tailwheel skills up, isn’t causing the most pollution our kids are exposed to. Why don’t we pay more attention to the fast food industry that prioritizes cars backed up in their drive-through lanes with engines idling, and air conditioning running on hot summer days, than to the people who responsibly park their cars and walk in.
Okay, I’m done ranting. Thanks for listening.
Very good Another issue with the use of auto gas in light planes is the manner in which the fuel industry handles it . A tanker that just hauled a load of diesel gets refilled with no lead compartments are not necessarily fully drained and flushed potential contamination Avgas by contrast is a garanteed product therefore a tanker is either dedicated to avgas only or is first flushed with no lead auto gas
@4:00 i was under the impression Knock occoured when the Air Fuel mixture ignighted early due to the compression in an engine simmilar to a diesel. And the higher the octane the less likely this is to happen and thus this is why higher compression engines need higher octane fuels, higher compression = higher performance. the Early ignition would happen as the pistion is still in the compression stroke and would overpressure the cylinder cauing engine damage.
As a FAA certified aircraft mechanic have you seen what the damages on the Lycoming and Continental engines that have used non-lead fuel (the fuel from gas stations) (also submitting to the FAA that you are going to use a different fuel)? The cost starts to rise on fixing engines with hot spots aka Detonation issues. You might want to tell the Aircraft Engine Manufacturer's (Lycoming and Continental) to design a better engine to handle those issues.
One of the problems with that Pan Am Clipper that had to return to NYC via SE Asia and Africa due to the outbreak of WWII in the Pacific was the low quality fuel along the trip. They could not get full power during takeoff. Lots of finger crossing.
I remember those tanker trucks carrying tetra ethyl lead. They were much smaller in diameter and length because of the weight of that lead molecule.
Simple, runs higher octane and stops pinging! Used in hot rods ect and planes ✈️
pump fuels generally peak out at 93 octane in the US… but to go higher you need more ethanol in the fuel.
You know, I am a little bit surprised the EPA let this go on for so long. You'd think at some point a decade or three ago they would've just said, "It's been long enough–figure this out, or your planes are grounded until you do."
If you can't get to the point, pfft blocked. Tittles mean stuff. Lead gasket sealer better than silicone for car parts why. Learn YouTube
This guy is a phony he may be a chemist has no clue how or why it is used
Mans talking about molecules and i keep getting distracted with models and things in the bookcase
I just finally sold a Pitts with a very high performance, 10 to 1 compression engine. 100 unleaded would not work for that airplane.
Think it's just a way to eventually end civilian aviation? I mean why does anyone NEED a personal aircraft?!? They could weaponize it!
The issue of "detonation" is pre-ignition. i.e. the fuel/air mixture igniting BEFORE the spark plug fires, which is timed relative to the piston coming to the top of the cylinder, creating destructive interference with the power stroke of another cylinder.
San Jose is trying to shut down Reid Hillview Airport for many years now and reclaiming the land due to its high value. For this, they spent millions of dollars on studies regarding how dangerous lead is to the area. Now that RHV switched to lead-free gas and lead is not an issue any more, they'll still shut it down.
Yo I live in San Jose, Ca it’s right up in my block 😭😭😭
The electric light aviation revolution can't come soon enough.
What we need is better, newer, lighter engines.
I know almost nothing about fuel chemistry. That doesn't matter at all. It isn't a chemistry problem. It's a motivational problem. The solution is to put a tax of 30% on all leaded fuel. Raise the tax by 5 percentage points per year. The solutions will magically pop into existence, found by people motivated to avoid the tax. Within a few years, everybody will have found an alternative fuel that meets their requirements.
Midroll ads with the first multi-minute ad appearing at less than 2 minute in? Sorry Scott, I terminated the video INSTANTLY. Simply not worth it.
Please consider disabling midroll ads like so many other content creators have done. Such ads are incredibly disruptive and let’s face it, nobody is going to click on such a disgusting grift.
I use alcohol and lotion on mine when I put them in my ear holes. Carefully. On rare occasion I wet them with saltwater and put them in my nose holes. Occasionally in the mouth hole with chlorhexidine
Line tech here that deals with 100LL avgas daily! The lead makes the fuel taste better than without it and a little sip of it keeps us going throughout the day!😋
The elimination of lead in cars started in 1975 when cars for that first model year, were equipped with catalytic converters. In most parts of the country, leaded automotive gas was still commonly available in diminishing amounts up through the 1980's and only completely eliminated by 1990.
This was pretty interesting. I'll forget >90% of it, but for 30 minutes I was captivated by the pursuit for unleaded aviation fuel.
You can make a gasoline with a RON in the 120's and MON in the 100's or 110's without any lead EASILY! It's just a matter of costs.
Just google the RON and MON for xylene, toluene, cumene and modern esters. Some almost at RON 140!
No lead needed!