Ethylene glycol and engine cooling

[Tommy Cookers]

....RR engines started out using 85 octane and had reached about 120 octane by the end of the war.

Just as an aside, they got it to 150 octane by late 43 or early 44, I can't remember specific dates. The mark 9 spitfires with the Merlin 66 used it to chase down V1s.

also as an aside ....
though by the military sometimes for practical purposes called 150 octane - there may be no such thing as 150 octane number

afaik
120/150 fuel means 120 and 150 PN (Performance Numbers) and the associated 'supercharge ratings'
not the Research Octane Number RON and Motor Octane Number MON ratings which inherently range between 0 and 100
btw the same CFC fixed design variable compression test motor is used today as c. 90 years ago
iso-octane (the 100 ON reference fuel) used and the knock-limiting compression ratio established (presumably at NA imep)
120 means the fuel tests (at 'lean' ie worst mixture detonationwise) at 120 PN ie 20% higher imep - implying 20% more power
150 PN means the fuel tests (at 'rich' ie best power mixture) at 50% - implying 50% more power
the higher imeps ie boost being obtained from air tanks
presumably induction air temperature standardised as in RON and MON tests ie cooling effect of rich mixture standardised
the blurb is here https://www.astm.org/Standards/D909.htm (supercharge method)
and D2699 (research octane number) and D2700 (engine octane number aka motor octane number) used for car gasoline
supercharge rating was developed for rating aviation fuels more knock-resistant than 100 Octane No ON
D909 uses reference fuels in a range from 85 octane to isoctane + 6ml/usgal TEL


postwar civil and military Avgas standards were/are 80/87PN 100/130PN 108/135PN 115/145PN
'rich' PN is much higher than 'lean' PN in typical Avgas due to unnaturally high content of alkylate, benzene, toluene, or xylene
'rich' mixture being AFRs of 0.55 or 0.6
typical Avgas ie 100/130 was a British contrivance that by the accident of WW2 became the global standard
somewhat to the distaste of eg the US whose 100/130 may be around 108/130 though sold as 100/130 PN spec
the Wright engines as in WW2 B-29 and postwar Turbocompound-powered airliners always needed 115/145
but Pratt & Whitney refused it because of the high TEL - 108/135 came from 115/145 with 100/130's TEL content
when the big engines retired the 100/130 (called 100L) was replaced by 100LL - this had/has slightly less lead (still a lot)

[J.A.W.]

The FIA is already 'going green' with FE, by powering its diesel-electric generators on bio-glycerol,
so mayhaps F1 will also use it as a coolant base (+ nano carbon additives) - or will the temptation
to use a coolant 'blow-off' scheme as a defacto fuel additive, like lube is, too - put the kybosh on it?

Or 'heavy water' D2O - as a coolant medium? That ~10% increase in density could be useful...


(Edit: typo corrected, & addit).

[J.A.W.]

....RR engines started out using 85 octane and had reached about 120 octane by the end of the war.

Just as an aside, they got it to 150 octane by late 43 or early 44, I can't remember specific dates. The mark 9 spitfires with the Merlin 66 used it to chase down V1s.

also as an aside ....
though it was by the military sometimes for practical reasons called 150 octane - it wasn't 150 octane

120/150 fuel means 150 PN (Performance Number) in supercharged test (not 150 ON Octane number)
(the same ASTE-fixed design variable compression test motor in use today as originated c. 90 years ago)
120 means the fuel tests (at 'lean' ie worst mixture detonationwise) at 120 (NB whether ON or PN is unclear at this moment)
150 PN means the fuel tests (at 'rich' ie best power mixture) at higher mep/'power' (boost from tank) than on 'lean' mixture

NOTE afaik
PN was written around 100/130 fuel (100PN and 100 Octane No ON are set coincident with this fuel)
its clear that 130 PN means the PN mep (power) is 130% of the 100 ON mep (power)
broadly implying the aircraft engine can get 30% more power when using a rich mixture and the higher boost so allowed
what's not clear is how 120/150 PN fuel compares (except that 150 PN means 150% of some power and not 150 Octane)
for aviation there's officially no ONs beyond 100 (unlike some road-related fuel ratings adding TEL to octane reference fuel)

postwar civil and military Avgas standards were/are 80/87PN 100/130PN 108/135PN 115/145PN
PN is much higher than ON in typical Avgas due to high content of eg alkylate, benzene, toluene, or xylene etc
100/130 was the main Allied fuel standard in WW2 - though US 100/130 may test around 108 0ctane it's sold as 100
the Wright engine as in the B-29 always needed 115/145
when the big engines retired the 100/130 (called 100L) was replaced by 100LL - this had/has slightly less lead (still a lot)

For those with an interest in development of 'hi-test' avgas for heavily boosted piston engines
back in the day, this site linked below has a cogent presentation using original documentation:

http://www.wwiiaircraftperformance.org/ ... -fuel.html

[Rodak]

Water injection was used for temporary power increases during dogfights or take off. The water/alcohol (so it doesn't freeze) injection was used to cool the engine.

From Wiki....

Due to the cooling effect of the water, Otto cycle aircraft engines with water injection can be made to produce more power through higher charge densities at the time of combustion. The additional charge density is typically achieved by allowing higher manifold pressures before the onset of detonation. This is normally done by adding or increasing the amount of forced induction or further opening of the throttle.

[J.A.W.]

Water injection was used for temporary power increases during dogfights or take off. The water/alcohol (so it doesn't freeze) injection was used to cool the engine.

From Wiki....

Due to the cooling effect of the water, Otto cycle aircraft engines with water injection can be made to produce more power through higher charge densities at the time of combustion. The additional charge density is typically achieved by allowing higher manifold pressures before the onset of detonation. This is normally done by adding or increasing the amount of forced induction or further opening of the throttle.

Oddly enough Rodak, during WWII, BMW engineers concerned about the heat-soak issues of their
air-cooled radial during hard-running at high power settings, tried adding MW ADI to their DFI mill,
but in the event, found that an extra injector spraying additional avgas into the supercharger eye
was less problematic, as an auxilliary cooling medium.

But of course, due to rules limiting fuel use, this isn't an option for F1 today.

[Rodak]

Back in the late 1980's I was running a Reynard FF2000 car for a customer and we were having cooling issues on hot summer days. IIRC the Ford 2 liter liked to run fairly cool (165°? - that seems too cool) for best power, so I set up a system that used a windshield (windscreen for you Brits) washer pump and a temp sensor so that water would be sprayed on the radiators if the temp got too high. Worked brilliantly! The heat of vaporization of water is pretty high, so it cooled things down quickly and didn't need much volume. I suspect it wasn't legal, but no one ever even knew it was there and I never asked.

[J.A.W.]

Indeed, Rodak I can recall seeing - decades ago, at the drag racing - judicious blasts of CO2
from a regular fire extinquisher being used - to 'dry' cool the mill of a big aircooled 2-stroke triple
dragbike very effectively, to rid it of power-sapping heat-soak build-up - between runs down the strip.

Later, in production-racing motorcyle events, I saw the same technique applied to the radiator
of liquid-cooled bikes during pit stops, to prevent boil-over when shut down after hard running.

Another 'trick' back then was to do tank fills from ~40 degrees below gas-churns, both to pack in
max volume, & offer added internal coolant effect, but this too is forbidden by F1 rules, nowadays.

[gruntguru]

Indeed, Rodak I can recall seeing - decades ago, at the drag racing - judicious blasts of CO2 from a regular fire extinquisher being used - to 'dry' cool the mill of a big aircooled 2-stroke triple dragbike very effectively, to rid it of power-sapping heat-soak build-up - between runs down the strip.

Later, in production-racing motorcyle events, I saw the same technique applied to the radiator of liquid-cooled bikes during pit stops, to prevent boil-over when shut down after hard running.

Another 'trick' back then was to do tank fills from ~40 degrees below gas-churns, both to pack in max volume, & offer added internal coolant effect, but this too is forbidden by F1 rules, nowadays.

Dick Johnson famously had a fire extinguisher plumbed to spray onto the intercooler of his Sierra Cosworth for Bathurst qualifying. Totally illegal of course but difficult to detect.

[gruntguru]

Water injection was used for temporary power increases during dogfights or take off. The water/alcohol (so it doesn't freeze) injection was used to cool the engine.

From Wiki....

Due to the cooling effect of the water, Otto cycle aircraft engines with water injection can be made to produce more power through higher charge densities at the time of combustion. The additional charge density is typically achieved by allowing higher manifold pressures before the onset of detonation. This is normally done by adding or increasing the amount of forced induction or further opening of the throttle.

Oddly enough Rodak, during WWII, BMW engineers concerned about the heat-soak issues of their
air-cooled radial during hard-running at high power settings, tried adding MW ADI to their DFI mill,
but in the event, found that an extra injector spraying additional avgas into the supercharger eye
was less problematic, as an auxilliary cooling medium.

But of course, due to rules limiting fuel use, this isn't an option for F1 today.

Rodak. The addition of methanol not only acts as an anti freeze but also significantly improves the detonation resistance compared to water alone. This was established by Harry Ricardo 100 years ago.

JAW. Adding fuel for ADI is not as effective as water:methanol or even straight water. This also was established by Harry Ricardo 100 years ago.

[J.A.W.]

^ Yeah gg, MW50 (50/50 Methanol/Water) ADI was successfully/widely used by the liquid-cooled WW2
German V12 DFI aero-engines (which would tolerate use of lower octane fuel than the BMW radial).

Although a useful addition to P&W's R-2800 aircooled radial used in US fighters (albeit no liquid-cooled
Allied fighter engine in service required it - with up to 150 grade avgas available) BMW found it caused
problematic engine damage, & so, when tests showed the C3 hi-test fuel already used by the FW 190
fighter could be utilized instead (as already descibed) with positive reliability/durability results.

So it was introduced into service, particularly for the low-level/hard-flown JaBo (fighter-bomber) units
for which heat-soak power-fade would allow the hot-pursuit/tail-chasing RAF Napier Sabre-powered Typhoons (which relished hard-running) to make an intercept, before the English Channel was re-crossed.

[AJI]

Indeed, Rodak I can recall seeing - decades ago, at the drag racing - judicious blasts of CO2 from a regular fire extinquisher being used - to 'dry' cool the mill of a big aircooled 2-stroke triple dragbike very effectively, to rid it of power-sapping heat-soak build-up - between runs down the strip.

Later, in production-racing motorcyle events, I saw the same technique applied to the radiator of liquid-cooled bikes during pit stops, to prevent boil-over when shut down after hard running.

Another 'trick' back then was to do tank fills from ~40 degrees below gas-churns, both to pack in max volume, & offer added internal coolant effect, but this too is forbidden by F1 rules, nowadays.

Dick Johnson famously had a fire extinguisher plumbed to spray onto the intercooler of his Sierra Cosworth for Bathurst qualifying. Totally illegal of course but difficult to detect.

The co2 extinguisher/IC trick was actually Fred Gibson, Dick wasn't that smart. It was legal. You had to have a fire extinguisher, but there was no rule saying it had to be full at the end of a run. He also ran a brake bias adjustment disgused as a dash illumination pot and delivered tech specs in Japanese so the scrutineers couldn't understand them...

[Tommy Cookers]

....The addition of methanol not only acts as an anti freeze but also significantly improves the detonation resistance compared to water alone. This was established by Harry Ricardo 100 years ago.
....Adding fuel for ADI is not as effective as water:methanol or even straight water. This also was established by Harry Ricardo 100 years ago.

also 2 other mechanisms whereby power is increased ....
1 methanol replaces some of the avgas fuel - that replacement gives 10% more heat than the replaced Avgas would have
(per mass of air used methanol fuel gives about 10% more heat than does avgas)
avgas fuelling rate was reduced during deployment of MW aka WI aka ADI
2 the MW cools the supercharging process and reduces the cost in crankshaft power for a given amount of supercharging

MW aka ADI aka ICAO Methmix was in quite widespread use by airlines with some piston engines and even some turbojets
I may have travelled that way by BAC 111 in E Africa

btw if we believe the internet the 3350 Wright Turbocompound gave 4250 hp with WI (but didn't fly)

[gruntguru]

The co2 extinguisher/IC trick was actually Fred Gibson, Dick wasn't that smart. It was legal. You had to have a fire extinguisher, but there was no rule saying it had to be full at the end of a run.

My mistake - it was actually Peter Brock that got caught. Brock wasn't that smart either but I can assure you that someone on Dick's team was smart enough even if Dick wasn't.