In the US avgas (which has similar lead content to pre-phaseout automotive gasoline) is 0.14% of gasoline usage and declining at about 5%/year.
Fuel supplied lead is a 99.86% solved problem which is solving itself.
Congress has been funding a program to develop lead free fuel which can safely power aviation piston engines, it is ongoing. Intermediate results are largely not available because it is required to protect all commercial entities participating. https://www.faa.gov/about/initiatives/avgas/
There is a big fight over Avgas going on in San Jose over Reid Hillview airport.
Yes, while total use of leaded fuel now makes up a tiny percentage, it is still measurably significant to the people who live in the flight path of a municipal airport.
They are using that as an excuse to close the airport since that's in an area where real state is highly valued. Reid Hillview is a 'relief' airport - that means it is used to shift small GA traffic away from San Jose airport.
Those aircraft will not disappear, they will just move to SJC a few miles away and pollute just as much.
I seriously doubt that, if the lead was removed overnight, they would change their minds and stop complaining about the airport. This NIMBY fight is older than that.
I feel similarly about my HOA who complains about noise pollution from SJC. The airport predates the houses by decades but now it is suddenly a problem.
There should be far more outrage about lead in avgas than there is today - maybe then the FAA and EPA would stop bickering and issue some new regulation. Noone wants to take responsibility for the monetary damage and possible disasters stemming from the decision to phase out lead, so decades later we are still looking for the perfect avgas replacement.
Meanwhile, European planes are transitioning to other fuels. Either Jet-A or motor gas. Diamond has developed great engines, but when their aircraft are sold in the US, guess which engines they use? People will ask specifically for lead burning Lycoming or Continental. If there was a penalty for doing that, maybe this would change.
Diamond has not developed great engines. There's a video floating around of them quite literally taking stock Mercedes taxi diesels apart and putting different oil coolers on them.
The only difference in design besides those oil coolers was their gearbox, which was a joke from day one. Firstly, diesel produces RPMs similar to what a small aircraft propeller wants so even having a gearbox is either a revenue-generating design intended to fail, or an exercise in stupidity. You can tell me which, I honestly don't know.
Nor has Diamond developed great aircraft in other aspects, either. Their stick rather than a yoke design was also a cost-cutter, but no one wants to ride around with a piece of metal hitting them in the balls, either. Socata and Cirrus did a much better job of interior design than Diamond, which is why they're still making ever-more-complex airplanes, and Diamond is flirting with bankruptcy.
The solution to general aviation getting rid of leaded gas is someone to make small turbines, and the only thing holding that back is the FAA.
What the heck. Fully FADEC controlled and reliable engines with automated runup tests, what's not great about them? That the original design was derived from the automotive industry?
I am not qualified to comment on the need of the gearbox. I would suspect that neither are you.
> their stick rather than a yoke design was also a cost-cutter, but no one wants to ride around with a piece of metal hitting them in the balls, either.
The large numbers of people flying RV10s seem to disagree. Diamond doesn't have a monopoly on the center stick. Passengers may not like the floor mounted stick, but pilots? Meh. The passenger stick is removable on the DA42 and 62.
You can't seriously take a Diamond Twinstar and tell me that's not a great aircraft.
> The solution to general aviation getting rid of leaded gas is someone to make small turbines
Right, I can picture it right now, a C172 with a turbine engine. Maintenance and fuel requirements aren't even in the same league, no matter how small this turbine is.
As shown elsewhere in this thread, the lead-free, drop-in replacement has been approved.
> What the heck. Fully FADEC controlled and reliable engines with automated runup tests, what's not great about them?
A run-up is a grand total of 4 inputs even on a gas engine with 2 ignition circuits (power, prop pitch, ignition 1, ignition 2). Automating this is not rocket science, it's a gimmick. Yes, the Diamond diesel is a Mercedes taxi cab diesel with an aftermarket gearbox and oil cooler.
> The large numbers of people flying RV10s seem to disagree.
Experimental aircraft are not an apples/apples comparison to certified aircraft, they are just barely airworthy.
> Right, I can picture it right now, a C172 with a turbine engine. Maintenance and fuel requirements aren't even in the same league, no matter how small this turbine is.
Because of the FAA. The cost to get an appointment with them prices most would-be competitors out of the market. The FAA exists to protect airline and defense contractor monopolies, period.
> What does TSG want for the firewall-forward package it is developing on the RV-10 (come on, I know you want to know)? “We are hoping to offer it for between $168,000 and $175,000 USD.”
From its quoted operating cost of 20-25 gallons per hour that's doable. The last gas piston single I owned held 92 gallons and burned 19 per hour in cruise (a turbo Lycoming 540). Range would be a tradeoff, because of the increased weight of the fuel, but the bigger hindrance is weight and balance mismatches, which brings us full circle to my original point:
The entire industry has been held teetering on the verge of bankruptcy by the FAA for the last 40 years. And by "FAA" I mean their corporate and military "customers" as they refer to them when emails get subpoenaed. No one in their right mind would design new light GA airplanes (Cirrus and Socata included). All of the domestic US manufacturers have either quit or gotten the "Goldman Sachs special" (bought, loaded with debt, intentionally bankrupted, and then sold off to Textron for the meager parts supply chain profits).
Flying machines were a great idea, unfortunately they were invented in a shithole country...
Counterpoint: if we remove the habitat for civil aviation, it will, in fact, disappear. And we should: it's just a nuisance and serves no real purpose. The idea that civil aviators provide disaster relief, as advocated by those who favor keeping Reid-Hillview open, is completely absurd. A single flight of a real aircraft such as a C-5 at SJC would carry more materiel than 1000s of GA operations.
KRHV and GA in general are part of an ecosystem. There is Angel Flight West for instance which is only possible because of small GA aircraft.
A giant aircraft requires a giant amount of fuel, a giant runway and a pilot who has spent a whole lot of hours flying non-commercially. Without GA and small planes, we might also not have sustainable commercial-aviation.
My CFI took off to go work for the airlines because of increased demand several months ago. Without GA he may not have had an opportunity to stay with aviation at all. One can not learn everything needed to fly an aircraft in a simulator.
That airport has 100 octane mogas available now. Pilots from other airports have been flying there to fuel up instead of using the 100LL at their local airport.
When I was doing my research on ULPower engines (which can burn 100LL, but they would prefer non-leaded), there were very few airports who offered unleaded fuel (UL94). I think, San Carlos / KSQL was the only one I found?
I wonder what KRHV closure would mean for unleaded fuel? So everybody would just switch back to 100LL? How is that supposed to help?
Wouldn't be more practical (from the point of lead pollution) to enforce non-leaded fuels in those small airports instead? My cursory research shows that lot (?) of these light planes (and, perhaps, the majority of the trainer/weekend hobby aircrafts) would happily burn non-leaded fuel (UL94, for instance), with corresponding STC.
Can you help us laypersons understand why leaded gas is still needed in GA engines? Is this as simple as using better valve seats or something? I mean cars haven’t needed leaded gas for a long time, why can’t GA aircraft just use modern parts / engines?
Because they were designed for leaded gas and you can't just modify certified aviation stuff without spending millions on the process of getting your modification approved.
I think it's more that most aviation piston engines were originally approved for use with leaded fuel, and things have been slow to change. At least some of them apparently run fine on the right unleaded fuel.
Not an aviation guy, but a car guy. Lead has historically been used to raise the octane rating of gasoline. Octane rating expresses the resistance of the fuel to "knock" which is the sudden explosion of the air-fuel mixture inside the cylinder versus a controlled burn and which can damage the engine. The main factor that raises the octane requirement of an engine is the compression ratio (max cylinder volume to min cylinder volume). High compression ratios generate more horsepower but require higher octane fuel. The other thing is that lead lubricates the valve seats preventing excess wear, but that's a solved problem with hardened valve seats.
Fuel supplied lead is a 99.86% solved problem which is solving itself.
Congress has been funding a program to develop lead free fuel which can safely power aviation piston engines, it is ongoing. Intermediate results are largely not available because it is required to protect all commercial entities participating. https://www.faa.gov/about/initiatives/avgas/
Here is a nice article from someone involved in avgas lead removal: https://www.avweb.com/insider/going-to-the-moon-was-easy-com...