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Leaded gas was a known poison the day it was invented (2016)

smithsonianmag.com

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Re: Leaded gas was a known poison the day it was invented (2016)

#131

Post by xyzzy21 »

paulkrush wrote: post #91

I guess we live on the shoulders of nastiness and things get better. So TEL was part of our boot sequence. What nastiness are we subjecting ourselves to today? BTW: The guy that invented TEL also invented CFCs! See Thomas Midgley Jr: https://en.wikipedia.org/wiki/Thomas_Midgley_Jr . This guy who invents awesome working chemicals that are tragically bad for people on a worldwide scale manages to exit life dues to his…

Well consider what EPA managers are up to in terms of suppressing science about newly introduced chemical and their risks based on science.

https://www.ucsusa.org/resources/attacks-on-science/epa-lead...

Re: Leaded gas was a known poison the day it was invented (2016)

#132

Post by missedthecue »

photochemsyn wrote: post #86

Pure gasoline is not that great of a motor fuel because it knocks (explodes when it's not supposed to during the internal combustion engine cycle). This is a major problem with high-compression airplane engines. However, tetra-ethyl-lead (think one lead atom bonded to four ethanols minus the oxygen atoms) was never necessary to combat the problem. Ethanol's anti-knock properties at a blend of 85% gasoline 15% ethanol…

A Tesla battery weighs as much as a Cessna 172. I don't know how practical a battery powered GA aircraft with competitive range would be.

Re: Leaded gas was a known poison the day it was invented (2016)

#133

Post by tjohns »

jabl wrote: post #118
tjohns wrote: post #107

Earlier quoted context omitted.

For what it's worth, unleaded avgas is already available at some of the Bay Area airports as of recent, and it's currently priced cheaper than traditional leaded avgas.

Do you specifically mean the new 100 octane unleaded mentioned in the article the parent linked to? If not, it could be some lower octane unleaded formulation. There are a couple of standards for these, but they have never caught on.

It’s UL94, so lower octane (94 octane, as the name suggests). However, this is still fine for lower performance aircraft that make up the majority of the GA fleet.

There’s been a lot of interest in it, especially in light of the recent discussions to close RHV in San Jose. I know one of the flight schools here just switched all their aircraft over to UL94.

Higher performance aircraft will need UL100, which is still not available, but is expected soon. There’s been significant progress in getting it approved over the last year.

Swift Fuels sells the supplemental type certificate aircraft owners need to use UL94. They are offering a free upgrade to the UL100 STC once it’s offered, so aircraft owners don’t have to pay twice to start using UL94 today.

Re: Leaded gas was a known poison the day it was invented (2016)

#134

Post by nate_meurer »

Aloha wrote: post #14
air7 wrote: post #6

> The most compelling option was actually ethanol. But from the perspective of GM, Kitman wrote, ethanol wasn’t an option. It couldn’t be patented and GM couldn’t control its production. And oil companies like Du Pont "hated it," he wrote, perceiving it to be a threat to their control of the internal combustion engine. I'm generally an avid beliver in free markets as an agent for positive change, so these types of "r…

TEL (tetraethyl lead) had and has other advantages over ethanol beyond patentability - Unlike TEL, ethanol is hydrophilic, which makes gasoline blended with it more apt to be contaminated with water, and other water containing contaminants, this is particularly relevant for aviation uses and also reducing incidences of vapor lock. TEL is also (more) rubber and seal friendly, other than the (very) high risk of lead to…

> TEL also acts as a natural lubricant of its own, the lead acting as lubricant, particularly on valve and other top end engine components.

This is a myth. TEL has no lubricative properties in engines. The reality is opposite; lead deposits are corrosive. From https://www.shell.com/business-customers/aviation/aeroshell/...:

"The temperature for Lead deposits to form tend to be favourable around the spark plugs (as the whole mixture is quite cool before the flame starts to propagate) and on the exhaust valve stem (as the mixture cools after combustion). The problem is that the deposits are electrically conductive, which shorts out the spark plug - and corrosive, which can start to attack the metal of the valve stems."

Re: Leaded gas was a known poison the day it was invented (2016)

#135

Post by gumby »

stjohnswarts wrote: post #84
gumby wrote: post #61

Earlier quoted context omitted.

> I'm generally an avid beliver in free markets as an agent for positive change, so these types of "revelations" are really disheartening. There are many such examples. Here’s one from my life: when I was in the pharmaceutical business one of the chemists developed a treatment for a fairly common disease. He and a couple of others tried it on themselves. We could have patented it and run it through clinical trials, b…

So the chemist and his friend had the exact same disease and it was successfully treated and they wouldn't release it because it could be made by someone else? Uh a recipe can be patented and that protects it from being sold. Compounding pharmacies can't magically ignore those patents if they don't want to get sued into oblivion or lose their license. I'm kind of skeptical of your story, sorry.

It’s not really practical to sue a thousand small businesses — you might not even hear about them. And anyway it’s better to go after a product with a protected high margin than try to fight where somebody else can attack your margin.

BTW it wasn’t “the chemist and his friend” — that would have been a crime. It was a few chemists in the company dosing themselves — also technically illegal but done all the time and generally excused if it’s a trivial scale and disclosed in your filings.

Feel free to be skeptical but those are the business issues.

Re: Leaded gas was a known poison the day it was invented (2016)

#136

Post by nate_meurer »

roamerz wrote: post #120
stjohnswarts wrote: post #77

Earlier quoted context omitted.

So we should just stop using airplanes because their fuel has lead in it? What?

Yes - brought to you by the same people that would stop you from eating beef because cows fart. From a tech perspective tetraethyl lead also has lubricative properties that add to exhaust valve longevity under high temperature conditions which may be one of the reasons it took so long to disappear.

No, this is a myth. In reality, lead fouling decreases engine performance and longevity. From https://www.shell.com/business-customers/aviation/aeroshell/...:

"The temperature for Lead deposits to form tend to be favourable around the spark plugs (as the whole mixture is quite cool before the flame starts to propagate) and on the exhaust valve stem (as the mixture cools after combustion). The problem is that the deposits are electrically conductive, which shorts out the spark plug - and corrosive, which can start to attack the metal of the valve stems."

Re: Leaded gas was a known poison the day it was invented (2016)

#137

Post by jvanderbot »

3grdlurker wrote: post #130
paulkrush wrote: post #91

I guess we live on the shoulders of nastiness and things get better. So TEL was part of our boot sequence. What nastiness are we subjecting ourselves to today? BTW: The guy that invented TEL also invented CFCs! See Thomas Midgley Jr: https://en.wikipedia.org/wiki/Thomas_Midgley_Jr . This guy who invents awesome working chemicals that are tragically bad for people on a worldwide scale manages to exit life dues to his…

I can only wish that more people realized that we didn’t have to start with something so destructive before we could “get better eventually”.

Implying we would know about all possible destructiveness at time of invention.

Re: Leaded gas was a known poison the day it was invented (2016)

#138

Post by gumby »

jzebedee wrote: post #69
gumby wrote: post #61

Earlier quoted context omitted.

> I'm generally an avid beliver in free markets as an agent for positive change, so these types of "revelations" are really disheartening. There are many such examples. Here’s one from my life: when I was in the pharmaceutical business one of the chemists developed a treatment for a fairly common disease. He and a couple of others tried it on themselves. We could have patented it and run it through clinical trials, b…

Have you written about this anywhere? I'm curious what common disease could be cured in the manner you described. It seems like the low-hanging fruit is already picked clean in the pharma industry.

It was using urea to fight topical fungal infections (anti fungal drugs are typically quite toxic). The mechanism of action has been well known for decades; what the folks came us with was a formulation that got the dosage high enough without causing damage. It was easily whipped up in the lab but I don’t remember the details. Any notes from this would be long gone as this was over a decade ago and the company has been sold and surely any paper lab notebooks are buried and forgotten.

Re: Leaded gas was a known poison the day it was invented (2016)

#139

Post by tialaramex »

Aloha wrote: post #100
bleachedsleet wrote: post #89

Earlier quoted context omitted.

It will be over, but it’s not over yet. Your link says that it will both take a while for it to come to market and also be more expensive to produce…an expense that will likely be balked at by the airlines until forced to use it at which point it will be the customers that pay.

Airlines (outside of bush planes) are not using AvGas in any substantive quantity, and have not been since the early 60's. The amount of AvGas used a year is dwarfed (several times over) by the amount of Jet Fuel (Jet A does not have TEL in it). AvGas (which uses TEL) is used by general aviation exclusively.

I would guess one thing that confuses non-pilots is that while say an A320 or a 747 looks like it has jet engines, lots of small regional aircraft (e.g. a Dash-8) visibly have propellers, and so it's natural for lay people to assume that's basically the same idea as on a Cessna 172 or a Spitfire scaled up.

But it isn't. Those planes aren't aren't fuelled by AvGas. Their engines use JetA (basically kerosene) because they've got a turbine inside like those turbofan engines which look so visibly different, however their turbine powers the propeller rather than a set of fans to drive more air through the engine and produce thrust that way.

https://en.wikipedia.org/wiki/Turboprop

Re: Leaded gas was a known poison the day it was invented (2016)

#140

Post by afavour »

paulkrush wrote: post #91

I guess we live on the shoulders of nastiness and things get better. So TEL was part of our boot sequence. What nastiness are we subjecting ourselves to today? BTW: The guy that invented TEL also invented CFCs! See Thomas Midgley Jr: https://en.wikipedia.org/wiki/Thomas_Midgley_Jr . This guy who invents awesome working chemicals that are tragically bad for people on a worldwide scale manages to exit life dues to his…

> What nastiness are we subjecting ourselves to today?

Maybe an overwrought comparison but I genuinely do feel like we’ll look back on this age of social media and disinformation in the same way we did leaded gas. The people making money knew exactly how dangerous it was and the problems it caused but they did everything in their power to cover it up in the name of profit. Originally it felt like a social annoyance and not much else but in this era of vaccine denialism, election fraud conspiracy theories, even body image issues from touched up photos, there’s little doubt in my mind that society is suffering and that the problem will likely get worse before it gets better.

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