Merlin power with Modern Tech but Unleaded Petrol

[swampyankee]

Lol I assume Monomethylaniline is the kind of stuff Walter White uses to make his 'product'.

No, he uses over-the-counter antihistamines. That's why you have to ask for them at the pharmacy counter. This is to prevent meth makers from buying gallons for conversion.

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When I worked at AVCO, back in the late '70s/early 80s, the test engineer running the ALF-502 altitude tests on AVCO's AJ Savage said the flight manager was seen spiking the 100/130 with TEL to bring it up to 115/145 so the R-2800s could run to full power.

 

[Shortround6]

a few comments.

How much lead you need to get to a certain octane or performance number varies enormously with the type of base stock you are using.
Around 1942 (?) the allies figured if they used 4.6 ccs per US gallon they could increase production of 100/130 fuel over 25% compared to using just 3.0 cc per gallon with the same basic supply of gasolines. (they would have less 91/96 octane though).

Toluene might work great for doping fuel in peacetime, however in war time the armaments industry is trying to make something called TriNitroToluene (TNT) and might have first call on Toluene supplies.


1400hp Grand Prix engine is good for about 700hp at 22,000ft.

 

[MIflyer]

Check this out. People have been vowing to put modern automobile engines in airplanes for decades, but it never seemed to work out very well. This guy seems to have licked the problem:

The $20 an hour Cessna 172 experiment | Air Facts Journal

 

[ThomasP]

Hey Snowygroudh,

re your post#15:

First: good post.

Second: Toluene, Xylene, Acetone, (and at least one other aromatic that I do not remember the name of at the moment) and Monomethyl Aniline, are all used fairly commonly in automotive gasoline, here in the US and in a lot of other countries around the world. I do not know how commonly they are use in the EU?

 

[special ed]

This fuel discussion has brought to mind an occasion from my teen years, 1957-58. It was Friday night after Civil Air Patrol meeting and I was waiting for the bus at the airport when I noticed an older cadet, a not very friendly one, with the hood open on his car. This car was an absolutely beautiful black '32 Ford coupe with motorcycle front fenders, bobbed rear fenders, large chromed headlights on the chrome mount between the front fenders, but the thing that has always impressed me was the 1949 Lincoln taillights that fit perfectly at the bottom edge of the rear deck. As the bus only came once an hour, I walked over to see if I could do anything. The engine was a flathead Ford with Weiand aluminum heads, a Weiand aluminum intake manifold with two Stromberg 97 carbs. When I asked, he said he was setting the distributor to full advance so he could win some money to go out Saturday night. He was going over to Pan-Air and fill the tank with 115/145. He would go to the incomplete Interstate 10 in New Orleans east where impromptu drag races were held (until the police came) and win money from the rich kids whose daddy's had bought them a '55 Chevy because they were the fastest around. Apparently, they didn't believe a flat head Ford could beat them. Years later when American Graffiti came out, I always enjoyed that movie.

 

[Admiral Beez]

In an airplane, you want something that can make good power for many hours at a time, and be reusable for 1,500 - 3,000 hours of operation. So, you do NOT want to push the HP/liter or cubic inch up anywhere near the limit; you want RELIABLE power.

That wasn't part of the OP. Racing aircraft need only hold themselves together for about a hour tops.

Talk to Cosworth or Riccardo, I think the biggest advantage today is we have the machines and technology as well as the materials to make what they knew back then a reality, 1800hp out of 27L today I feel would be quite easy to achieve.

I'd have to think a 27 L engine today would generate close to 3,000 hp. I assume we're looking for liquid cooled rather a radial, but our modern 27L engine wouldn't be a V-12 like the Merlin. Instead it would be a compact 24 - 48 cylinder X engine. The 8L W-16 on the Bugatti Chiron Super Sport generates 1,578 hp.

Combine three of these into one unit, add some structure and weight for greater reliability and the 27L 48 cylinder will be close to 4,000 hp.

 

[wuzak]

Didnt the BMW M12/13/1 produce 1400hp from 1.4L on standard street fuel? A result of very effective intercooling and high RPM presumably.

Power was estimated to be around 1,400hp, as BMW didn't have an engine dyno that could measure that amount at the time.

This was a qualifying rating - useful for 3 or 4 full-on qualifying laps (at that time qualifying allowed a maximum of 12 laps in 1 hour of qualifying. Those laps included the ones leaving and re-entering the pits).

The race tune, good for a single ~300km race, was around 900-1,000hp. Maximum power was at around 10,000rpm.

The capacity was 1.5L, and the fuel was most assuredly not "standard street fuel".

the fuels contained around 80% toluene and were poisonous and enormously expensive, costing up to USD $300 per litre at the time

Banned: Rocket fuel · RaceFans

 

[wuzak]

Modern F1 standard engines can run 4bar boost with fuel you can buy from a commercial fuel station on the street (a select few in the UK at least sell 99 RON octane stuff (Shell V-Power).

While a current F1 engine could run on high octane commercial petrol, the race fuels are custom synthetic blends. The rules limit what can be done, and specify a fuel that is similar to commercial fuels.

A couple of years ago the FIA felt compelled to insert a regulation that restricted the maximum static compression ratio of the engine to 18:1. Since all that information is held closely by the manufacturers, it is not clear if any of them where approaching that amount of compression.

That goes with ~4 bar/58psi MAP (ie ~3 bar/43.5psi boost).

Maximum power in the 10,500rpm (lowest rpm with maximum fuel flow allowed) - 12,000rpm range.

 

[wuzak]

1400hp Grand Prix engine is good for about 700hp at 22,000ft.

Assuming that the turbocharger doesn't have enough capacity to compensate for altitude.

 

[Admiral Beez]

Assuming that the turbocharger doesn't have enough capacity to compensate for altitude.

Wouldn't a dual or triple stage supercharger be a better bet?

 

[GregP]

Hi Admiral Beez,

I didn't mention racing airplanes. I mentioned Formula 1 engines only because it fully illustrates that the horsepower can be produced rather easily from a much smaller engine than 27 litres. But, doing it in an F1-size package brings with it very short engine life. No Air Force wanted or wants a short-life engine. The worst were the German engines, which almost universally had much shorter overhaul times than Allied engines. This was not due to any inherent design weakness but was rather due to the poor-quality raw materials available for making metals used in engine manufacturing. There was and is nothing wrong with German engineering.

In WWII, the time between overhauls was never about when the engine was considered "worn out." It was all about the fraction of engine blocks that could be rebuilt and not scrapped. They set the overhaul time so that 95%+ (from memory ... possibly higher) of the engine blocks could be rebuilt, not because the engine was performing badly. As they gained experience, the time between overhauls became higher. By the end of the war, the overhaul time for both Merlins and Allison was considerably higher than it was early in the war because experience showed that the engine blocks were not being harmed by normal operations.

Cheers.

 

[Shortround6]

Assuming that the turbocharger doesn't have enough capacity to compensate for altitude.

That would assume that they were using a larger, heavier turbo charger than needed for the race car at or near sea level. It also assumes that the larger turbo would be operating at decent efficiency at an air flow far from normal.

 

[Koopernic]

Thanks for all your replies. Got this from PBehn's link (thanks)

Aviation spirits with TEL used in WWII reached 150 octane to enable supercharged engines such as the Rolls-Royce Merlin and Griffon to reach high horsepower ratings at altitude.[19] In military aviation, TEL manipulation allowed a range of different fuels to be tailored for particular flight conditions.

In 1935 the licence to produce TEL was given to IG Farben, enabling the newly formed German Luftwaffe to use high-octane gasoline. A company, Ethyl GmbH, was formed that produced TEL at two sites in Germany with a government contract from 10 June 1936.[20]

So if the Germans had TEL why were they running their planes on 87 Octane?

After a little distillation the fuel that came out of Bergius hydrogenation plants at about 74 RON (off the top of my head). Adding TEL increased this to 87 RON and that was how B4 fuel was created. To create early gren dyed C3 they added about 22% iso-octane. Thus for the same coal input one got about 70% as much C3 as B4. All number of the top of my head but came from fischer-tropsch.org.

To create iso-octane they combined syngas over chromium catalysts to create butanol which they dehydrated into iso-butylene which was polymerised to iso-octane.

Unfortunately the iso-butylene was also required for BUNA-S and BUNA-N synthetic rubber and this limited the German high octane fuel supply.

Standard Oil (Now Exxon) who owned Ethyl and I.G.Farben (now BASF) actually swapped patents. Standard Oil got the rights to BUNA-N and BUNA-S rubber the I.G.Farben got the right to make TEL.

It was a great deal for the Americans as the Germans had no source of oil and synthetic iso-octane was so expensive they could never export it. It became a huge industry in the US.

There were other octane enhancers I think tin and ferrous based the Germans had.

American iso-octane initially came out of butylene from oil cracking and latter catalytic cracking and 100 octane increased because USAAF refused to buy anything else giving the refiners motivation.

Anglo Oil (now BP) developed something called acid alkylation that allowed the production of 100/130 fuel in vast quantities. It was extremely efficient.

The Germans started acid alkylation plants in 1940 but I believe only 1 actually was commissioned in 1943.

This is a crude description of the situation in the first 1/3rd of the war. Things changed and new technology came in.

 

[Deleted member 68059]

While a current F1 engine could run on high octane commercial petrol, the race fuels are custom synthetic blends. The rules limit what can be done, and specify a fuel that is similar to commercial fuels.

A couple of years ago the FIA felt compelled to insert a regulation that restricted the maximum static compression ratio of the engine to 18:1. Since all that information is held closely by the manufacturers, it is not clear if any of them where approaching that amount of compression.

That goes with ~4 bar/58psi MAP (ie ~3 bar/43.5psi boost).

Maximum power in the 10,500rpm (lowest rpm with maximum fuel flow allowed) - 12,000rpm range.

The numbers I provided are from first hand experience.

 

[pbehn]

There has been all sorts of jiggery pokery with fuels in F1, I remember a brief period when some cars had a fire in the pits but there was hardly any visible flame, like methylated spirit, very dangerous for all concerned because the driver had to be told.

 

[SaparotRob]

I remember seeing a replay of an invisible fire in the pits. I can't remember if it was F1 or CART series. Very scary. How do you fight a fire you can't see?

 

[Koopernic]

Below is an article about NREL making triptane out of biomass.
Race for a Better Fuel Begins with NREL Researchers

Triptane was once seen as the magical material with a RON of 170 with both sides trying to synthesize it in WW2. In actuality it's RON is about 113 lean.

"Hensley's ongoing research could make racing fans take notice. He and his colleagues in the laboratory's Thermochemical Catalysis Research and Development group have created a catalyst that converts biomass into a hydrocarbon mixture rich in 2,2,3-trimethylbutane, also known as triptane. Triptane is added to gasoline to reduce engine knocking, to boost the octane rating, and to increase the motor's efficiency. The biofuel NREL developed is 85% triptane.

"When we purify the crude product we just boil off some of the lower octane components, predominantly light hydrocarbons," Hensley said. "Once we get up to a concentration of about 85% triptane, we don't see much benefit in increasing the purity. Octane rating doesn't increase much above 85% triptane, and it also happens to be an easy stopping point in the distillation. Going above about 88% purity requires a lot more energy."

The anti-knock number, often called the octane rating of gasoline, varies from 85-87 for regular grades to 91-94 for premium grades in the United States. The 85% triptane mixture produced at NREL registers an estimated octane rating of 107. NREL's fuel is better suited for race cars because current standard engines aren't designed to take advantage of such high octane."

107 MON octane lean is pretty good.

I suspect aviation piston engines will make a come back. The Celera 500L with its laminar flow fueselage will prove it.

I believe triptane was in commercial production and did find its way into aviation fuels.

 

[SaparotRob]

Below is an article about NREL making triptane out of biomass.
Race for a Better Fuel Begins with NREL Researchers

Triptane was once seen as the magical material with a RON of 170 with both sides trying to synthesize it in WW2. In actuality it's RON is about 113 lean.

"Hensley's ongoing research could make racing fans take notice. He and his colleagues in the laboratory's Thermochemical Catalysis Research and Development group have created a catalyst that converts biomass into a hydrocarbon mixture rich in 2,2,3-trimethylbutane, also known as triptane. Triptane is added to gasoline to reduce engine knocking, to boost the octane rating, and to increase the motor's efficiency. The biofuel NREL developed is 85% triptane.

"When we purify the crude product we just boil off some of the lower octane components, predominantly light hydrocarbons," Hensley said. "Once we get up to a concentration of about 85% triptane, we don't see much benefit in increasing the purity. Octane rating doesn't increase much above 85% triptane, and it also happens to be an easy stopping point in the distillation. Going above about 88% purity requires a lot more energy."

The anti-knock number, often called the octane rating of gasoline, varies from 85-87 for regular grades to 91-94 for premium grades in the United States. The 85% triptane mixture produced at NREL registers an estimated octane rating of 107. NREL's fuel is better suited for race cars because current standard engines aren't designed to take advantage of such high octane."

107 MON octane lean is pretty good.

I suspect aviation piston engines will make a come back. The Celera 500L with its laminar flow fueselage will prove it.

I believe triptane was in commercial production and did find its way into aviation fuels.

I hope you're right. Piston engined airplanes just sound so nice.

 

[Koopernic]

I hope you're right. Piston engined airplanes just sound so nice.

The technology section of the OTTO aviation website for the Celera gives the foillowing for the piston engine.

OTTO AVIATION

RED A03 Engine Specifications

• Liquid cooled V12, twin 6-cylinder bank, capable of independent operation with mutually independent critical engine sub-systems for each bank
• Type certification approval granted via EASA (TC.E.150) and FAA (E00092EN)
• Certified to operate on readily available Jet A1 and biodiesel
• Capable of 550+ takeoff horsepower and best-in-class fuel efficiency
• Controlled via fully redundant electronic engine control unit with single power control lever reducing pilot workload
• Lightweight, all-aluminum design

Sound bites of the craft in the air are hard to find but it does sound like a big WW2 piston engine.

The nice thing is something called "PtL "Power to Liquids" which captures CO2 from the air (Direct Air Capture) or from Sea Water (where concentration is 143 x that of air) combines it with hydrogen from electrolysis to produced fuels such as the above. These fuels are carbon neutral. Petrol may never die.

USN once looked at making jet fuel at sea on its nuclear aircraft carriers. It would probably work now given the advances in catalysts.

 

[pbehn]

That wasn't part of the OP. Racing aircraft need only hold themselves together for about a hour tops. I'd have to think a 27 L engine today would generate close to 3,000 hp. I assume we're looking for liquid cooled rather a radial, but our modern 27L engine wouldn't be a V-12 like the Merlin. Instead it would be a compact 24 - 48 cylinder X engine. The 8L W-16 on the Bugatti Chiron Super Sport generates 1,578 hp.

View attachment 622017

Combine three of these into one unit, add some structure and weight for greater reliability and the 27L 48 cylinder will be close to 4,000 hp.

The 130/131 Merlin series engine produced 2060BHP, it isnt a massive leap of faith to think they could improve by 50% in 10 to 20 years if Jet engines didnt exist.