What If Tetraethyl Lead additives were banned in the 1920s? Effects on WW2?

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wuzak

Captain
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Jun 5, 2011
Hobart Tasmania
It was well known that Tetraethyl Lead was toxic by the time that it became an additive to fuel for knock resistance.

After some deaths in a production facility, sales of TEL were suspended for a year and a conference held into its health issues. That, and other studies that were held in the following years, sometimes conducted by the lead industry, found that there was little health risk to the public.

But what if warnings from a few scientists were heeded and TEL sales permanently banned from 1925?

The other anti-knock additive being proposed at the time was ethanol. Had that been adopted what would aircraft performance have suffered?

How would ranges have been affected by petrol/ethanol blends? Fuel economy is ~3-4% worse with E10 compared with regular petrol.
 
A good chance most countries would have ended up using EisenPentaCarbonyl (aka IronPentaCarbonyl) instead of TEL. It is also toxic, but to a lesser degree (I think) than TEL in most circumstances.

Otherwise, alcohol as you mentioned above, and/or a significantly higher percentage aromatic content.
 
People were also adding benzene to the gasoline in late 1920s/early 1930s (at least?). The mixure of benzene/gasoline 80/20 was used on the BMW VI 7,3 (denotes 7.3:1 compression ratio), for 750 HP. The VI 6,0 was using the benzene/gasoline 40/60 mix, for up to 660 HP. The BMW VI 5,5 that used only the gasoline of the day was good for 650 HP.

All per data from January 1929. I don't know what kind of octane rating can we 'attach' to the gasoline used in that time.
 
I don't know what kind of octane rating can we 'attach' to the gasoline used in that time.
For US gasoline it ranged from a low of 38? to high of about 70. The oil in the US varies considerably as it was spread out from Pennsylvania to California. And oddly enough, the general progression of "gasoline" from those oil fields follows from the low 38-40 fuel of Pennsylvania to higher in Texas and ending up with the around 70 fuel California.

During WW I and through parts of the 1920s the US military specified the fuel by area (east coast vs west coast or Penn vs Cal fuel) as they knew there was a difference, they just couldn't measure it.

Alcohol has several problems for aircraft fuel, only one of which is the reduction in heat energy per gallon.
While gasoline and water do not mix, alcohol mixes with both and can pull water into the "mix" rather than allow water to collect at the bottom of a tank.
Alcohol has a higher freezing temperature than gasoline and a higher auto ignite temperature which makes cold weather operation more difficult. Operation can be cruising at higher altitudes, not just staring up.
Benzene also has cold temperature problems
 
used how?
Tetraethyl Lead gave different changes in knock rating using the same amount of lead depending on the gasoline it was mixed into (base stock) and the refining process, and the octane rating of the base fuel and it changed with the amount of led used. Going from 5cc of lead to 6 ccs gave a much small change that going from 1 cc to 2 cc's of lead in the same gasoline.

lead gave a greater boost to paraffins than it did to olefins, naphthenes, and aromatics for the same amount of lead.

I am sure that I left out some of the other things affecting the use of lead.
I doubt that EisenPentaCarbonyl was any easier to use.
 
Hey Zipper730,

I have been looking for a while but so far have not been able to find a comprehensive write-up on the development and use of eisenpentacarbonyl in a single source, so I put the following general info together.

Eisenpentacarbonyl (aka iron-pentacarbonyl aka iron-carbonyl) works as an anti-detonate, ie it does not allow gasoline to detonate as easily, and also slows down the burn rate of the gasoline. It is a good enough detonation and burn rate inhibitor that it is(was?) sometimes used for fire-fighting/suppression when mixed with other appropriate substances.

Basically iron-pentacorbonyl Fe(CO)5 is 5 carbon-monoxide molecules linked to 1 iron atom, with the oxygen atoms being shared by all.

When large amounts of oxygen become available at high temperatures and pressures the iron-pentacarbonyl absorbs some of the available heat energy, allowing some of the carbon-monoxide molecules to combine with the oxygen atoms to form carbon-dioxide molecules. The other resulting compound is iron-carbide (FeC3), which is a very abrasive material, and in the 1920s and 1930s it caused relatively severe wear on the engines. The 1 extra oxygen atom is free to be used in the combustion process. (Note that I am not a chemical engineer and my description of the process could be wrong to a degree - hopefully a very small degree.:oops:)

IG Farbin developed iron-pentacarbonyl (I think) in the early-1920s, and in 1925 they bought the rights to the brand of Monopolin fuel (a blend of ethyl alcohol, aromatics, and iron-pentacarbonyl) and were experimenting with various substance to alleviate the iron-carbide problem, but did not succeed before WWII. Monopolin reportedly had a much higher anti-knock rating than the usual distilled natural gasolines and the early cracked petroleum gasolines of the time, and was in fact commonly used for auto-racing by the Germans. There were tests in the 1920s performed by the Germans where they would break the engine before they encountered knock.

Interestingly, Kettering and Midgley (the 2 scientists credited with developing TEL) also experimented with iron-pentacarbonyl in the mid-1920s, in case the use of TEL was banned, but decided not to proceed (due to their inability to patent the compound) when use of TEL was allowed to continue.

In the end a relatively simple solution was developed through the addition of a stabilizer containing aluminum, preventing both the breakdown of the iron-pentacarbonyl over time and reducing the formation of abrasive iron-carbide. But, by the time this happened WWII was ongoing and TEL was in large scale production/use.

It is similar to TEL in that it is considered flammable, toxic, and a health hazard.

Unlike TEL, because it readily breaks down in the environment resulting in non-toxic compounds like iron-oxides and various carbon compounds, it is not considered to be an environmental hazard.

Unlike TEL, in the 1930s it was relatively cheap to make in bulk - at <3% of the cost of TEL.

Unlike TEL, it can be used as a fuel all on its own, and when used by itself it has an octane rating of 50. When mixed at 6ml/USgal of standard unleaded gasoline (such as today's 89 octane) it acts like 98 octane. It also acts in a similar manner when used with aromatic and alcohol based fuels.

blah :study: Hopefully this makes sense.
 
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People were also adding benzene to the gasoline in late 1920s/early 1930s (at least?). The mixure of benzene/gasoline 80/20 was used on the BMW VI 7,3 (denotes 7.3:1 compression ratio), for 750 HP. The VI 6,0 was using the benzene/gasoline 40/60 mix, for up to 660 HP. The BMW VI 5,5 that used only the gasoline of the day was good for 650 HP.

All per data from January 1929. I don't know what kind of octane rating can we 'attach' to the gasoline used in that time.
Benzene is absolutely lethal stuff. Barely better than TEL for health reasons. There was quite a bit of research going on in early WW2 period in the USA on getting the "unleaded" knock value of fuels up, as it was recodnised that TEL was really damaging engines above certain concentrations and could not be just increased and increased to get higher boost limits.
 
I doubt that removing TEL or replacing it with something else would have had that much of an effect on range or reliability.

Most sorties didn't use an aircraft's full load of fuel. Most engine reliability issues were due to factors other than exact fuel composition (e.g., oil/coolant systems).

Extreme long range ferry operations and bombing raids (e.g., Doolittle Raid) might have been negatively affected, as well as CAP operations where every bit of fuel counted.

Operationally, perhaps a tiny fractional increase in non-operational aircraft and/or reduced range might have had an impact for extremely long-range bomber operations like the RAF and USAAF offensives of 1943-45. Unfortunately, it's almost impossible to get the sort of boring operational readiness figures needed to make intelligence comparisons, even for well-organized and victorious air forces like the USAAF.

OTOH, widespread use of TEL might have had bad effects on childrens' IQ scores even a few years after its introduction (although things like lead paint, lead solder for food cans, and lead in the soil would have been much more serious problems at the time). By 1940, that means that your average 18 year-old recruit might have lost a point or two of IQ or otherwise suffered slight mental impairment, at least if they came from heavily urbanized areas. That means a slightly smaller pool of suitable Air Force recruits or recruits with subtle mental problems. So, maybe TEL in fuel was a wash overall - slightly reduced engine problems, but slightly less effective mechanics and aircrew to operate and maintain the aircraft.
 
I doubt that removing TEL or replacing it with something else would have had that much of an effect on range or reliability.

Most sorties didn't use an aircraft's full load of fuel. Most engine reliability issues were due to factors other than exact fuel composition (e.g., oil/coolant systems).

Extreme long range ferry operations and bombing raids (e.g., Doolittle Raid) might have been negatively affected, as well as CAP operations where every bit of fuel counted.

Operationally, perhaps a tiny fractional increase in non-operational aircraft and/or reduced range might have had an impact for extremely long-range bomber operations like the RAF and USAAF offensives of 1943-45. Unfortunately, it's almost impossible to get the sort of boring operational readiness figures needed to make intelligence comparisons, even for well-organized and victorious air forces like the USAAF.

OTOH, widespread use of TEL might have had bad effects on childrens' IQ scores even a few years after its introduction (although things like lead paint, lead solder for food cans, and lead in the soil would have been much more serious problems at the time). By 1940, that means that your average 18 year-old recruit might have lost a point or two of IQ or otherwise suffered slight mental impairment, at least if they came from heavily urbanized areas. That means a slightly smaller pool of suitable Air Force recruits or recruits with subtle mental problems. So, maybe TEL in fuel was a wash overall - slightly reduced engine problems, but slightly less effective mechanics and aircrew to operate and maintain the aircraft.
The higher the anti-knock rating the higher compression ratio you can run, which dramatically impacts fuel economy. So I`d have a careful think about your first statement.
 
There are charts in old text books showing what 1cc to 6 ccs per US gallon would do to certain kinds of gasoline.

However I don't think that the Allies used more than 4.6 ccs per gallon in any fuel spec.

Post war (Korean war) fuel specs called for not more than 4.6ccs in in MILITARY 91/96, 100/130 and 115/145 fuels and commercial fuel was limited to 2.0ccs in 91/96, 3.0 ccs in 100/130 and 108/135 and 4.6 ccs in 115/145.

The higher limits for military fuel was to allow much increased production, should it be needed. Depending on fuel base stocks, available additives/blending agents and whatnot military fuel didn't always have the max limit of allowable lead.

It was well known that high amounts of lead, even with additives, could lead to exhaust valve and valve seat problems (durability ?) and spark plug fowling problems (reliability).
Commercial operators were willing to trade more expensive fuel for lower maintenance costs and/or less down time for maintenance. A plane that is sitting on the ground waiting for spark plug changes isn't making any money.

Edit, just saw the other thread which has veered off into fuel/s.
I don't know if 100/150 fuel was a "standard" fuel. It was certainly used in Britain and N W Europe but perhaps not in the quantity that some people think?
I am not sure it was used much of anywhere else. Like Italy of the Far East?
 
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For US gasoline it ranged from a low of 38? to high of about 70. The oil in the US varies considerably as it was spread out from Pennsylvania to California. And oddly enough, the general progression of "gasoline" from those oil fields follows from the low 38-40 fuel of Pennsylvania to higher in Texas and ending up with the around 70 fuel California.

During WW I and through parts of the 1920s the US military specified the fuel by area (east coast vs west coast or Penn vs Cal fuel) as they knew there was a difference, they just couldn't measure it.

Alcohol has several problems for aircraft fuel, only one of which is the reduction in heat energy per gallon.
While gasoline and water do not mix, alcohol mixes with both and can pull water into the "mix" rather than allow water to collect at the bottom of a tank.
Alcohol has a higher freezing temperature than gasoline and a higher auto ignite temperature which makes cold weather operation more difficult. Operation can be cruising at higher altitudes, not just staring up.
Benzene also has cold temperature problems
Here is a Bureau of mines study of the various base stocks used to produce av gas in WWII. It also shows the effects of adding various amounts of TEL to base stocks as well as the effect of adding aromatics such as Cumene and CS (Cumene substitute).
1654048083545.png
 

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There are charts in old text books showing what 1cc to 6 ccs per US gallon would do to certain kinds of gasoline.

However I don't think that the Allies used more than 4.6 ccs per gallon in any fuel spec.

Post war (Korean war) fuel specs called for not more than 4.6ccs in in MILITARY 91/96, 100/130 and 115/145 fuels and commercial fuel was limited to 2.0ccs in 91/96, 3.0 ccs in 100/130 and 108/135 and 4.6 ccs in 115/145.

The higher limits for military fuel was to allow much increased production, should it be needed. Depending on fuel base stocks, available additives/blending agents and whatnot military fuel didn't always have the max limit of allowable lead.

It was well known that high amounts of lead, even with additives, could lead to exhaust valve and valve seat problems (durability ?) and spark plug fowling problems (reliability).
Commercial operators were willing to trade more expensive fuel for lower maintenance costs and/or less down time for maintenance. A plane that is sitting on the ground waiting for spark plug changes isn't making any money.

Edit, just saw the other thread which has veered off into fuel/s.
I don't know if 100/150 fuel was a "standard" fuel. It was certainly used in Britain and N W Europe but perhaps not in the quantity that some people think?
I am not sure it was used much of anywhere else. Like Italy of the Far East?
1654048999453.png


1654049986679.png


The British switched the majority of their production to 100/150 in 1944. Of course their total production was dwafed by the US.

1654049156767.png


The Merlin was exceptionally well suited to take advantage of 100/150 as its performance at lean mixtures was greater than anticipated

Merlin Mild Engine.png

From WWII Aircraft Performance

1654049873827.png

100/150 was also used by the 8th AF
 

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Benzene is absolutely lethal stuff. Barely better than TEL for health reasons. There was quite a bit of research going on in early WW2 period in the USA on getting the "unleaded" knock value of fuels up, as it was recodnised that TEL was really damaging engines above certain concentrations and could not be just increased and increased to get higher boost limits.
Calum,

The difference is that benzene is just carbon and hydrogen, so it's not dangerous after combustion and degradation. Tetra-ethyl lead contains, well, lead, and you can't get rid of it.

Once the TEL goes through combustion, the lead is carried into the atmosphere by by the hot exhaust gasses and can be inhaled; it also ends up in soil and water where it can be directly ingested or taken up by plants and then concentrated as it passes up the food chain.

So the difference is danger to people handling it vs. widespread environmental contamination no matter what. A gross simplification, but a good starting point.
 
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The British switched the majority of their prediction to 100/150 in 1944. of course their total production was dwafed by the US.

Thank you for the information/correction.

Do you have any idea how long the 100/150 fuel specification lasted?
In 1947 according to one engine year book (secondary source) the US was using 115/145 while the British were rating a couple of Merlins/Griffons on 115/150.
I have no idea if the 115/150 was an invention of the author/editor.
In the 1948 edition the 115/150 references have gone away and been replaced by 115/145 but it appears the power ratings (Max power) stayed the same.
 
Here is a paper describing the state of the art in the refining industry in WWII.
The dominance of the USA is mind boggling
1654195425355.png
 

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