General Forums => Aircraft and Vehicles => Topic started by: awrabbit on January 31, 2017, 01:15:16 PM
Title: Fuel Octane differences?
Post by: awrabbit on January 31, 2017, 01:15:16 PM
ok..... my question how is HT modeling the fuel?
and also is he basing his test on USAAF tests of captured enemy planes with the high octane fuel that the US used or is he using the lower octane fuels that we available in the other countries?
has always been a question.
this would skew the performance data gathered. and I find it hard to believe that the axis and the USSR aircraft had this uber performance like they do in AH based on the stories that I have read these countries had a much poorer quality fuel that would significantly change the performance.
thought or facts?
Title: Re: Fuel Octane differences?
Post by: Zimme83 on January 31, 2017, 01:44:46 PM
We dont have any 150 octane fuel in the game so the allied planes using it irl dont have the same top performance in the game as they had with 150 octane fuel. Spit XIV is the best example, with 150 octane fuel it would have been a true monster.
Edit: The spit IX (Or rather the in game XVI) gained 30 mph top speed and 950 fpm climb with +25 lb/sq.in boost instead of the +18 lb/sq.in boost it have in game, that would put it almost equal to a in-game D-pony on wep...
Title: Re: Fuel Octane differences?
Post by: Zimme83 on January 31, 2017, 02:06:49 PM
Compare the charts and the gain in performance with 150 octane fuel is obvious: (http://www.spitfireperformance.com/spit14+25lbs.jpg) (http://hitechcreations.com/components/com_ahplaneperf/genchart.php?p1=0&p2=64&pw=2>ype=0&gui=localhost&itemsel=GameData)
Title: Re: Fuel Octane differences?
Post by: awrabbit on January 31, 2017, 02:12:36 PM
very interesting read good info.
Title: Re: Fuel Octane differences?
Post by: Zimme83 on January 31, 2017, 02:19:07 PM
Both the D-pony and spit 14/16 would be perked with 150 octane fuel. A spit faster than a Tempest and outclimbing a K-4 is maybe not what we want... the later Jug:s would prob face perking too
Title: Re: Fuel Octane differences?
Post by: Devil 505 on January 31, 2017, 03:34:42 PM
What you have to remember is that in order to utilize 150 octane, the engines must be tuned-up to run at higher power setting first. If you can't just pour in 150 octane fuel into a plane tuned for a lesser octane rating and have any benefit. Same principle applies to any change to a higher octane fuel from where you started. Octane rating is just that fuel's ability to resist detonating from the compression and heat in the cylinder before the spark plug fires.
Title: Re: Fuel Octane differences?
Post by: Zimme83 on January 31, 2017, 04:14:46 PM
Of course, but we're just assuming that the engines are optimized. Hard to compare the performance otherwise.
Title: Re: Fuel Octane differences?
Post by: GScholz on January 31, 2017, 04:40:27 PM
While the Japanese did suffer from several quality issues for various reasons, the European Axis powers did not lag behind the Allies in fuel quality. German C3 fuel was pushing 140PN near wars end.
Title: Re: Fuel Octane differences?
Post by: GScholz on January 31, 2017, 04:47:17 PM
Just a friendly reminder that the 109K4 we have in AH runs on B4 fuel and has ~1770 hp. In 1945 there were C3 powered K4s flying in Reich's Defense with ~2200 hp.
Title: Re: Fuel Octane differences?
Post by: Randall172 on January 31, 2017, 04:54:35 PM
give all planes the same fuel!
Title: Re: Fuel Octane differences?
Post by: Devil 505 on January 31, 2017, 04:55:23 PM
Just a friendly reminder that the 109K4 we have in AH runs on B4 fuel and has ~1770 hp. In 1945 there were C3 powered K4s flying in Reich's Defense with ~2200 hp.
That is about 200hp to high. Late war German fuel had quality issues.
Now don't go doing a Kurfurst on us. The only unit was one staffel that did operational testing in Dec 44-Jan 45. The use of 1.98ata was not cleared for use til late March 45 and there is no proof that the 4 Gruppen authorized to do so actually did.
Title: Re: Fuel Octane differences?
Post by: GScholz on January 31, 2017, 07:23:22 PM
100/150 octane Allied fuel had its issues as well. It was really at the limit of chemical technology. There is plenty of photographic evidence of 109K's with C3 fuel markings.
Title: Re: Fuel Octane differences?
Post by: MiloMorai on January 31, 2017, 07:36:36 PM
Did the Allied fuel turn to sludge like late German fuel?
Quote
There is plenty of photographic evidence of 109K's with C3 fuel markings.
Yes but no MW50.
Title: Re: Fuel Octane differences?
Post by: GScholz on January 31, 2017, 08:31:49 PM
They all do eventually. The shelf life of gasoline is typically around three months. It will eventually turn into a vaseline like jelly. However the problem with 100/150 avgas was separation of the TEL octane booster, causing lead fouling of the engine.
Title: Re: Fuel Octane differences?
Post by: Oldman731 on January 31, 2017, 09:34:42 PM
They all do eventually. The shelf life of gasoline is typically around three months. It will eventually turn into a vaseline like jelly. However the problem with 100/150 avgas was separation of the TEL octane booster, causing lead fouling of the engine.
Yikes! GScholz is back! Dude!
- oldman
Title: Re: Fuel Octane differences?
Post by: GScholz on January 31, 2017, 09:40:35 PM
Hey Oldman :cheers:
I pop in now and then to see if there's anything interesting going on. Not much lately though.
Title: Re: Fuel Octane differences?
Post by: colmbo on February 01, 2017, 09:24:26 AM
I just wanted to clarify that the power gains are not from the fuel but the engine tuning.
What engine tuning? What specifically are you saying is done? Is it timing? Mixture? What?
I have no experience with the super high-octane fuels but do have time in the B-17 and B-24. Present day they use 100LL. We used the performance numbers for the 96 octane fuel since that is the closest spec in the operating specs for each airplane. Using the 96 specs meant a slightly lower maximum manifold pressure but there were no changes to the engine "tune". Just wondering what you're talking about.
Title: Re: Fuel Octane differences?
Post by: Devil 505 on February 01, 2017, 11:58:46 AM
What engine tuning? What specifically are you saying is done? Is it timing? Mixture? What?
I have no experience with the super high-octane fuels but do have time in the B-17 and B-24. Present day they use 100LL. We used the performance numbers for the 96 octane fuel since that is the closest spec in the operating specs for each airplane. Using the 96 specs meant a slightly lower maximum manifold pressure but there were no changes to the engine "tune". Just wondering what you're talking about.
My knowledge in engine mechanics comes from experience as an auto mechanic, but the principles of internal combustion engines remains the same.
The manifold pressure is a measurement of the air/fuel mixture volume before entering the cylinder. It relates to the throttle setting. Where Octane comes into play is in ensuring that the fuel can handle the pressure and heat inside the cylinder during compression. As the mixture is compressed, it heats up, and is ignited by the spark plug as the piston reaches top-dead-center to propel it downwards. If the cylinder is too hot or the mixture is compressed too much, the fuel will ignite early and resist the piston's upward momentum towards top-dead-center - causing reduced power and possible engine damage. Camshaft and spark timing must be adjusted to ensure that the fuel ignites at the exact moment to provide maximum force on the piston. FYI: Diesel engines operate by being designed to compress the mixture until combustion.
While higher throttle settings will increase mixture volumes to a small degree, the large gains are made by making mechanical changes to increase either the volume of the cylinder or the volume of fuel/air mixture. Increasing the cylinder size would happen at a manufacturer level in the case of a military engine. So let's concentrate on increasing the volume of fuel/air inside the normal sized cylinder. An adjustment in camshaft timing can give some performance gains, but it is better to change the cam to one with a lobe shape to open the intake valves earlier and close them later. Another method would be to change the the gearing of the supercharger to force more air into the manifold and open up the fuel jets/injectors to account for more air. Same idea for turbochargers as well. The final method would be to add a cooling additive (such as nitrous oxide) into the manifold to super-cool the air into a denser charge, allowing for higher volume in the cylinder - also requires additional fuel delivery.
Hope that helps.
Title: Re: Fuel Octane differences?
Post by: GScholz on February 01, 2017, 01:05:55 PM
Title: Re: Fuel Octane differences?
Post by: awrabbit on February 01, 2017, 02:25:32 PM
good stuff.
I agree there would be some tuning involved and even with that, the real advantage would be with the compression upped a few notches and some porting on the intake side of the heads to handle increased volume. larger valves intake and exhaust, would keep the exhaust side on the outer port a little tighter tapered or, even maybe stock to increase the bottom end grunt of an engine. also the camshafts would need to be ground to optimize and handle the the higher fuel air volume with more lift and duration/overlap. then ya get into valve springs, turbo charger gearing, better rings...... yada yada yada. with that said engine life would suffer and would create more service work for the ground crews.
could you imagine running up on a 51 with those kind of mods and the fuel to go with it? yikes.... then some NOS just for fun :)
however the bottom line would be with a hotter plugs, hotter mags, and some induction tuning there would create some advantage with the higher octane fuels.
Title: Re: Fuel Octane differences?
Post by: GScholz on February 01, 2017, 03:00:33 PM
It's not just a matter of compression ratios as these engines all used forced induction. With forced induction the fuel-air mixture is already compressed by the blower/turbo before being pushed into the cylinder where it is compressed again. With just some minimal tuning you could increase the boost from the blower and gain significant power without modifying the engine itself. The same with ADI systems like water injection, or adding an intercooler between the blower and carb. Just by adding water injection in the blower on the DB 605 in the 109G-6 (turning it into a 109G-14) they could increase the boost and get 300 more hp out of it.
It is essentially the same thing you see with the insane power outputs the "ricers" get out of their tiny Japanese engines running on racing fuel and huge turbo/intercooler setups.
Title: Re: Fuel Octane differences?
Post by: Devil 505 on February 01, 2017, 04:41:08 PM
With just some minimal tuning you could increase the boost from the blower and gain significant power without modifying the engine itself.
Right, but that still involves mechanical changes to the gearing and impeller of the supercharger. That is not exactly "minimal work." You are still looking at a manufacturer level change in design followed by the production of new parts.
Title: Re: Fuel Octane differences?
Post by: GScholz on February 01, 2017, 05:11:11 PM
That depends on the blower design. On most designs you would at least have to change the belt/chain sprockets or change internal gearing. On the DB 600 series however the blower was not directly driven off the motor by a belt or chain, but by a hydraulic coupling. It was a large single-stage blower with variable speed independent of engine RPM. That's why the 109s have such smooth power curves. The speed of the blower was automatically controlled and also depended on air pressure/altitude. So on that engine increasing boost pressure was just a matter of tuning this blower control system.
Title: Re: Fuel Octane differences?
Post by: icepac on February 01, 2017, 08:15:20 PM
Concerning testing of captured enemy planes on high octane US fuel...................
Yes the fuel is higher octane and better quality but it will not provide "extra horsepower" over the fuel the airplane was designed to run..............unless the "testers and technicians" who prepared the planes for flight deviated from the factory settings and advanced the ignition timing and raised boost pressure.
The only advantage likely seen by the testing would have been a safety margin concerning detonation.
The engine management systems are not like the ones in modern cars that can take advantage of higher octane fuel because the ECU will be able to use more advance.
I seriously doubt the guys prepping the captured planes for testing deviated from the factory settings as defined in the manuals and likely left timing and boost pressure unchanged from when they acquired the aircraft.
Title: Re: Fuel Octane differences?
Post by: GScholz on February 02, 2017, 02:13:59 AM
It's not only octane rating that's important, but also the aromaticity and chemical makeup of the fuel. German synthetic fuel was too different from Allied petroleum based fuel that the RAF were unable to properly test the 109E before they had captured some German fuel in Africa. The DB would run rough and foul its spark plugs on Allied avgas.
Title: Re: Fuel Octane differences?
Post by: awrabbit on February 02, 2017, 02:51:35 PM
We used to put 100LL in our cars in the old days for street racing and it helped out. was much cheaper than race fuel at the track. even with the additives for aircraft. we would run a richer mixture in the secondary side and also jet up a little on the primary's and pull up the timing. I know for a fact Octane does increase power. for naturally aspirated or blowers/superchargers. you can see it in time slips at the drag strip. pump gas 93/94 octane will produce a couple 10th's lower ET ( even better with cold dense air) and MPH. hotter fuel+ more air = more torque and Horsepower.
you can tell the difference between 8 lbs of boost and 10 for sure.
then I went to nitrous uhhg.... everything comes down.... timing,shift points. the problem of stages and also the damage it does to motors when not tuned right. Valves/plugs/ lifting heads. the weather factors in big time. unless you very conservative.
also you are correct increasing the boost and raising over all compression would be redundant.( what was I thinking ) with the super charging. increasing the compression with the blower drive would give increase the power. dropping the compression and using variable supercharger gearing. the 51 has a 2 stage super charger so there are options with gearing.
as for turbos.... I am just starting to get involved in the turbos and there is is a lot of tun-ability in the modern turbos.. not so sure about the technology of what was available back then. I know I am planning on twins on my Challenger this year. :D going for 1100 hp on 94 pump gas.
well.... the USA fuels were better quality overall and if we are going on the test numbers from US testing then I think the over all performance is askew a little. just my thoughts. perhaps not a big difference but, maybe enough to count. I am sure that if we tested these aircraft the mechanics made sure they were well tuned.
Title: Re: Fuel Octane differences?
Post by: GScholz on February 02, 2017, 03:03:50 PM
In other words you had already made up your mind before even starting this thread, and it is essentially just a rant. Check.
I know for a fact Octane does increase power. for naturally aspirated or blowers/superchargers. you can see it in time slips at the drag strip. pump gas 93/94 octane will produce a couple 10th's lower ET ( even better with cold dense air) and MPH. hotter fuel+ more air = more torque and Horsepower.
you can tell the difference between 8 lbs of boost and 10 for sure.
Octane has nothing to do with the fuel being "hotter" or not. There is no more energy in a gallon of 100PN gas than in a gallon 87PN. If you drive on 87 PN and 8 lbs boost you will make just as much power as on 100 PN and 8 lbs of boost. It doesn't matter what fuel they put in the captured Zeke as long as the engine liked it and the pilot stayed within the RPM and boost restrictions in the pilot's handbook.
Title: Re: Fuel Octane differences?
Post by: awrabbit on February 02, 2017, 07:15:50 PM
In other words you had already made up your mind before even starting this thread, and it is essentially just a rant. Check.
Octane has nothing to do with the fuel being "hotter" or not. There is no more energy in a gallon of 100PN gas than in a gallon 87PN. If you drive on 87 PN and 8 lbs boost you will make just as much power as on 100 PN and 8 lbs of boost. It doesn't matter what fuel they put in the captured Zeke as long as the engine liked it and the pilot stayed within the RPM and boost restrictions in the pilot's handbook.
No was curious as to if the higher octane fuel was used for testing captured aircraft or if the performance numbers were from the country of origin of the aircraft.
I knew the allies used hotter fuel but, was unclear as to what was used or how the performance numbers were gathered.
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Title: Re: Fuel Octane differences?
Post by: awrabbit on February 02, 2017, 07:21:12 PM
No was curious as to if the higher octane fuel was used for testing captured aircraft or if the performance numbers were from the country of origin of the aircraft.
I knew the allies used hotter fuel but, was unclear as to what was used or how the performance numbers were gathered.
Sent from my iPhone using Tapatalk
There was no rant at all intended. Just curious and got some education.
A lot of sharp people involved in this community. <S>
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Title: Re: Fuel Octane differences?
Post by: FBKampfer on February 15, 2017, 05:02:17 PM
It should be noted that the 190A3 and later models were required to use C3 fuel by their BMW 801D's. The chemical synthesis of the artificial C3 fuel was relatively straightforward, but the infrastructure was simply of limited capacity.
Pre war, intention had been to transition the Luftwaffe exclusively to synthetic C3 fuel, leaving refined B4 fuel for the Heer. But production never managed to reach required levels, and so B4 continued to be used wherever possible, while C3 was for 190 units, and units operating high altitude interceptor variants of the 109, such as the G5, and G6,G14/As models.
Throughout the war, synthetic fuel had shown stability problems, but certainly nothing insurmountable. It was distributed on as-needed basis, and only in 1944 did fuel supply issues affect the Luftwaffe to any significant degree. And it's important to remember that it affected the entirety of the Luftwaffe, including units running B4 fuel.
Thought general logistics isn't my expertise, I would hazard a guess that it was in large measure related to the Allies targeting transportation hubs. Stop the fuel, stop the fighters.
Title: Re: Fuel Octane differences?
Post by: PR3D4TOR on February 16, 2017, 02:42:39 PM
B4 is also synthetic. A3 and C2 are natural.
Title: Re: Fuel Octane differences?
Post by: Krusty on February 16, 2017, 02:56:43 PM
Concerning testing of captured enemy planes on high octane US fuel...................
Yes the fuel is higher octane and better quality but it will not provide "extra horsepower" over the fuel the airplane was designed to run..............unless the "testers and technicians" who prepared the planes for flight deviated from the factory settings and advanced the ignition timing and raised boost pressure.
The only advantage likely seen by the testing would have been a safety margin concerning detonation.
You're not taking into account the Japanese engine development and wartime practices of the time.
Take, for example, an engine DESIGNED for 130 octane. Now add in such deplorable production quality and then top it off with lack of 130 octane gas. What are you going to do? Just... put some 87 octane in it and tell the pilots "don't run it above xxx inches"
Then what happens when the US (for example) gets a captured version, cleans it up and with no real changes other than making sure it all functions, puts 130 octane gas in it?
The Japanese engine development was full of pittfalls and setbacks and their ambitions surpassed their abilities by a lot. They had more engine teething problems and delays than most US planes had -- and we've had our share! Many of their fuel sources were contaminated, or thinned down with sap-based turpentine just to keep the fight going. It didn't matter if the quality was less, when pilots were still taking the fight to the US forces. Several tales from Zero pilots recount how they used poor fuel and could not meet even the factory specified numbers. The planes would belch and spit and sputter and even trail gray smoke streams at times during combat. This was the norm.
Now imagine that engine got a total overhaul and was fixed with perfect new seals, gaskets, clean oils, fresh gas of the best quality? Guess what -- it's going to behave a HELL of a lot better in the US tests than the Japanese tests.
Just saying...
Title: Re: Fuel Octane differences?
Post by: Devil 505 on February 16, 2017, 03:16:54 PM
Now imagine that engine got a total overhaul and was fixed with perfect new seals, gaskets, clean oils, fresh gas of the best quality? Guess what -- it's going to behave a HELL of a lot better in the US tests than the Japanese tests.
I doubt that any engine parts were overhauled unless absolutely necessary. Why risk damaging parts that are extremely difficult to get a hold of? And it's not like the plane came with an English language manual for tear-down and assembly procedures.
Title: Re: Fuel Octane differences?
Post by: PR3D4TOR on February 16, 2017, 03:29:04 PM
All this speculation is pointless. If someone (and you know who you are) have documentation then post it.
Title: Re: Fuel Octane differences?
Post by: DaveBB on February 16, 2017, 04:07:06 PM
Where's the famous KI-84 and KI-100 test documentation?
Title: Re: Fuel Octane differences?
Post by: Krusty on February 16, 2017, 04:17:10 PM
Where's the famous KI-84 and KI-100 test documentation?
Oh you mean the documentation that showed that for a time 2/3 crashed on takeoff from the factory into the trees, making the people who built them sad? Or the ones where the engines would never output even at rated basline levels, so much that outdated Kis were faster and more reliable? Or the many reports where Ki-84s would take off but not make enough power to climb up to even mid-level attackers because their engines were struggling to run at all?
Plenty of documentation for all of that has been shown before.
>:)
Title: Re: Fuel Octane differences?
Post by: Krusty on February 16, 2017, 04:23:19 PM
I doubt that any engine parts were overhauled unless absolutely necessary. Why risk damaging parts that are extremely difficult to get a hold of? And it's not like the plane came with an English language manual for tear-down and assembly procedures.
Okay, I mis-used the word "overhaul" -- you're right. But they often did have to do a lot of work on these captured airframes. One they found flipped on its back after force-landing on a tiny island in the middle of the ocean. It had been days before a sub spotted it and more before they could get in there, remove the dead pilot, and figure out how to cart it off. All while sitting on a salt-sprayed beach. Doesn't lend itself to keeping an engine in good keep. They'd try to replace some seals and gaskets if they were brittle and worn, and in some cases (not specific to IJN captures) they had to do a lot of work and were best-guessing what they should do. RAF captured Fw190 tests were pretty well botched because they had unbalanced the trim and weren't running the engine properly. Just one example.
Title: Re: Fuel Octane differences?
Post by: Zimme83 on February 16, 2017, 04:30:49 PM
But all this is of course irrelevant when we talks about AH as long as mechanical errors and production issues are not modeled. ALL our planes have better performance and reliability than the real world fighters had. Production issues, rushed development, poor fuel and a bad day decreased the performance for most fighters.
We all know that a lot of fighters had a lot of mechanical issues but no one would accept having random engine failures etc just because it happened in the real world..
Title: Re: Fuel Octane differences?
Post by: PR3D4TOR on February 16, 2017, 05:28:21 PM
Okay, I mis-used the word "overhaul" -- you're right. But they often did have to do a lot of work on these captured airframes. One they found flipped on its back after force-landing on a tiny island in the middle of the ocean. It had been days before a sub spotted it and more before they could get in there, remove the dead pilot, and figure out how to cart it off. All while sitting on a salt-sprayed beach. Doesn't lend itself to keeping an engine in good keep. They'd try to replace some seals and gaskets if they were brittle and worn, and in some cases (not specific to IJN captures) they had to do a lot of work and were best-guessing what they should do. RAF captured Fw190 tests were pretty well botched because they had unbalanced the trim and weren't running the engine properly. Just one example.
Then wouldn't it be a safer bet to say that the crashed and jury-rigged IJN/IJAAF aircraft in the U.S. tests probably performed worse than in Japanese service, just like the RAF Fw 190. Way to go on shooting down your own argument.
Title: Re: Fuel Octane differences?
Post by: PR3D4TOR on February 17, 2017, 08:41:18 AM
Found the report on the U.S. Zeke test:
They had problems with the propeller not allowing maximum RPM.
Quote
the propeller on this particular Zero airplane is not set to permit maximum allowable r.p.m. (maximum obtainable r.p.m. was 2075)
They did not use the best available U.S. fuel and recognized that the engine had timing issues and thus had reduced performance during the tests.
Quote
91 octane fuel was used in the conduct of all tests, and at full throttle at 10000 feet no detonation was experienced. This indicates that timing was probably slow, insomuch as engine is reportedly designed to operate on 100 octane fuel; normal performance probably was still further reduced thereby.
They did not understand the mixture controls, or the controls themselves were not in working order.
Quote
Mixture control - Use of this control is not fully understood, as in the rear position of this lever, mixture control is automatic. Movement of the lever to any forward position at any altitude causes no perceptible change in engine operation.
So they tested a crashed Zeke that they repaired without having spare parts or factory documentation. They did not use any higher grade fuel than what the Japanese were using, they couldn't figure out the mixture controls, the engine timing was off and the propeller governor did not allow maximum RPM. I think it is pretty safe to assume this Zeke performed rather poorly compared to its brethren in Japanese service at the time.
Title: Re: Fuel Octane differences?
Post by: Krusty on February 17, 2017, 03:26:29 PM
According to many Japanese pilots that flew it in combat, not so much. Again, you need to get a wider sampling and look at actual war-time records.
It wouldn't be safer to say that it performed better than the test. As a total "system" of combat there were many considerations including the fuel and oil flowing through the engine. It would be safe to say it gave the US a data point when they had none at all. It was SOMEthing for them to look at to use, but it could be better, and it could be worse. For example, the Ta-152-H-0 test flown did about what ours does on WEP but without any "go-juice" because the H-0s and most of the 152s got a mid-life engine retuning to run hotter without actually needing additive boosts. They had factory engineers make the rounds and effect minor changes and this had real world effects on the plane's combat performance that aren't quite reflected in-game. Kind of like the Spit12 got for the fuel flow constrictor in the carbuerator.
Title: Re: Fuel Octane differences?
Post by: MiloMorai on February 17, 2017, 03:47:51 PM
Quote
Kind of like the Spit12 got for the fuel flow constrictor in the carburetor.
???
Title: Re: Fuel Octane differences?
Post by: Krusty on February 17, 2017, 03:50:27 PM
The Spit12 had a gravity-fed carb that would sputter in low-Gs. They put a restrictor on the feed so that it would pool and feed in, so that in moments of low-G it wouldn't sputter out and die. See Miss Shilling's orifice.
EDIT: Not important. Just an example of an comprehensive modification that changed performance for the better.
Title: Re: Fuel Octane differences?
Post by: MiloMorai on February 17, 2017, 04:15:45 PM
The Spit12 had a gravity-fed carb that would sputter in low-Gs. They put a restrictor on the feed so that it would pool and feed in, so that in moments of low-G it wouldn't sputter out and die. See Miss Shilling's orifice.
EDIT: Not important. Just an example of an comprehensive modification that changed performance for the better.
It was used on Merlin engined Spits well before the Griffon engined Spit XII.
Title: Re: Fuel Octane differences?
Post by: Zimme83 on February 17, 2017, 06:06:08 PM
If it says spit 1 and 2 then its more accurate.
Title: Re: Fuel Octane differences?
Post by: PR3D4TOR on February 17, 2017, 07:59:06 PM
According to many Japanese pilots that flew it in combat, not so much.
Quote me one Zeke pilot claiming his ride under-performed in 1940-1943. You can't.
Title: Re: Fuel Octane differences?
Post by: Perrine on February 20, 2017, 09:51:33 PM
We have perk points for airplanes...
How about introducing perk points for special weapons, fuels and equipment? This opens lots of possibilities to spice up this stale game again.
Perk fuel - high octane fuel available to select planes based on historical records
Perk ordinance - IL-2 and Yak-9 PTAB, aerial rockets for me 262, for example
Perk equipment - computer gunsights like in p51, for example
Just make sure it can only be used once and work hard to earn it back again.
Example, land 5 victories in a Mustang D and perk add-ons become available. You get the option to take high octane fuel (based on actual records) or a k-14 computer gunsight... You can not take both. Once used you gotta earn it again by landing 5 victories using the standard in-game issued mustang D
Title: Re: Fuel Octane differences?
Post by: Zimme83 on February 21, 2017, 03:15:41 AM
If you can land 5 kills then you dont need it, and it would lead to even more vulching and cherry pickin so -1
Title: Re: Fuel Octane differences?
Post by: Brooke on February 22, 2017, 01:54:27 AM
They had problems with the propeller not allowing maximum RPM.
They did not use the best available U.S. fuel and recognized that the engine had timing issues and thus had reduced performance during the tests.
They did not understand the mixture controls, or the controls themselves were not in working order.
So they tested a crashed Zeke that they repaired without having spare parts or factory documentation. They did not use any higher grade fuel than what the Japanese were using, they couldn't figure out the mixture controls, the engine timing was off and the propeller governor did not allow maximum RPM. I think it is pretty safe to assume this Zeke performed rather poorly compared to its brethren in Japanese service at the time.
All of this is correct except for the fact that the test referred to above was not from a U.S. test but from a test that took place in Kunming, China. The top speed for this A6M2 Zero was around 290 mph so yes, it performed rather poorly compared to its brethren in Japanese service at the time.
The link to this test can be found here:http://www.wwiiaircraftperformance.org/japan/p5016.pdf (http://www.wwiiaircraftperformance.org/japan/p5016.pdf)
This test also points out that the engine used in the Zero was "of almost identical design to our own Pratt & WhitneyR-1535 series". More importantly, the test states that "the engine is reportedly designed to operate on 100 octane fuel". I believe at this time in the war, the Japanese were using 91 octane fuel in their airplanes.
The link to the U.S. test of the Aleutian Zero or Koga's Zero can be found here: http://www.wwiiaircraftperformance.org/japan/intelsum85-dec42.pdf (http://www.wwiiaircraftperformance.org/japan/intelsum85-dec42.pdf)
In my book, "Cracking The Zero Mystery", they state that the engine was indeed overhauled upon the plane's arrival in San Diego. The Zero wasn't damaged very badly at all and performed as good as if not better than the Zeros our pilots were facing in the Pacific. I would say there's a good chance that we ran 100 octane fuel in it since the China test pointed out the engine was designed for it in the first place. Since the Japanese were using 91 octane at the time, the 326 mph top speed is probably a little high for the A6M2s we were facing as I pointed out in one of my previous posts - True Top Speed for the A6M Zero on Jan. 28.
Title: Re: Fuel Octane differences?
Post by: Guppy35 on April 04, 2017, 12:07:19 PM
Make it stop!!!!
Do you guys know how many times this same 150 octane fuel debate has raged here? I was hoping against hope that someone just dredged up an old thread but no! Please make it stop! :)
Title: Re: Fuel Octane differences?
Post by: Rich46yo on April 09, 2017, 08:06:28 PM
I was always under the impression the Germans had more issues with fuel quality then we did, most of all during the BOB, and even when they got it straightened out some they still had to tune engines specifically to fuel type and that their better synthetics was always in short supply while the Allies never worried about aviation fuel stocks.
The Japanese situation I know about but maybe someone could clarify better about The Luftwaffes experiences with their fuel. Thank you.
Title: Re: Fuel Octane differences?
Post by: Mike Williams on April 13, 2017, 06:31:59 AM
Do you guys know how many times this same 150 octane fuel debate has raged here? I was hoping against hope that someone just dredged up an old thread but no! Please make it stop! :)
Presumably you prefer "alternative facts"?
Title: Re: Fuel Octane differences?
Post by: MiloMorai on April 13, 2017, 07:22:39 AM
Just Hungarian lawyer facts. :x :devil
Title: Re: Fuel Octane differences?
Post by: Guppy35 on April 16, 2017, 10:31:17 PM
LOL can't say that's the truth Mike. I'm a WW2 history junkie just like you for over 40 years now. My specialty is the Spit XII if it helps. If you happen to come across Steve Brew's massive two volume history of 41 squadron, you'll find that much of my research fills Volume II covering the Spit XII era. Phil Listemann's book on the XII also has my stuff in it. So no, Alternative facts aren't an interest.
My point is, we've been over this stuff before, including yourself. Your material has been quoted many times. We've posted images showing 51s with 150/100 Octane written in the Data Blocks from the ETO. We've done everything under the sun before to show that factually it happened.
Problem is, folks want it so they can make the game easier, not for some great historical accuracy. I believe the folks at HTC have despite our many attempts to show the 'facts' decided that for game play, giving Spits, Temps, 51s etc 150 octane fuel would not help game play so leaving it as it is, was their decision.
We could obviously take for example, the Spitfire V in AH. Initially we had an LF Vc even though visually it looked like a Vb. It was a beast down low as the LF V was designed to be. For game play reasons I imagine, we got backdated to the early Vb that isn't nearly the performer the LF V was in AH. Our IX has a Merlin 61 when historically the majority of IXs had Merlin 66s. So it doesn't perform as well at the altitudes in AH that a Merlin 66 bird would.
You can go on and on with the "Facts', but combining them with the need for even out the game play seems to be a fact as well.
Here is one of the first discussions of 150 fuel. 17 years ago. There are 25 other threads if you search 150 Octane where folks are making their pitch.
Title: Re: Fuel Octane differences?
Post by: PR3D4TOR on April 17, 2017, 04:59:15 AM
The Spit LF Vc was last V and is a 1942 bird and not representative for the V that fought in many famous battles in North Africa and over the Channel in late-1940 and 1941 against 109Fs and later the 190A. The AH Spit IX is a 1942 version meant to fill the slot for an early IX vs 190A time frame. The Spit XVI is for all intents and purposes a clipped wing Spit LF IX and fills that role for late war IXs. There's also the VIII for a full wing Merlin 66 Spit.
Title: Re: Fuel Octane differences?
Post by: PR3D4TOR on April 17, 2017, 05:05:16 AM
However I will add that a tropicalized Vc would be great for Far East scenarios.
Title: Re: Fuel Octane differences?
Post by: thrila on April 17, 2017, 10:19:08 AM
The Spit LF Vc was last V and is a 1942 bird and not representative for the V that fought in many famous battles in North Africa and over the Channel in late-1940 and 1941 against 109Fs and later the 190A. The AH Spit IX is a 1942 version meant to fill the slot for an early IX vs 190A time frame. The Spit XVI is for all intents and purposes a clipped wing Spit LF IX and fills that role for late war IXs. There's also the VIII for a full wing Merlin 66 Spit.
Please bear in mind that the Bf 109F in AH uses 1942 boost settings.
We had the spit LF Vc in AH several years back, she was quite the little plane under 10k and was very popular- a bit too popular if i recall correctly. It would probably see a lot of use in AH if it was remodelled, but maybe not to the same extent with the greater variety of aircraft now present in AH.
My wishlist for a new spit would be a seafire L IIc or L III (this isn't to say I would say no to a spit Vc by any means). Despite the LIII being the most produced seafire and L IIC the most produced varient of the seafire IIC I think it's unlikely due to it's performance relative to other carrier fighters for MA gameplay.
Title: Re: Fuel Octane differences?
Post by: Guppy35 on April 17, 2017, 11:54:23 AM
The Spit LF Vc was last V and is a 1942 bird and not representative for the V that fought in many famous battles in North Africa and over the Channel in late-1940 and 1941 against 109Fs and later the 190A. The AH Spit IX is a 1942 version meant to fill the slot for an early IX vs 190A time frame. The Spit XVI is for all intents and purposes a clipped wing Spit LF IX and fills that role for late war IXs. There's also the VIII for a full wing Merlin 66 Spit.
LOL Thanks for the Spitfire education :aok
You prove the point. What you just typed is what's been said by me and others any number of times regarding the Spit line up. It's representative even if not exactly historical. Having flown the 41 Spit Vb in a 43 scenario, it was certainly evident it was not an LF V.
The point is the same for the 150 octane fuel. Players bemoan Runstangs, Spit 16s, etc. Now imagine the whining if they had the performance from 150 octane. I truly believe we don't have 150 octane for that very reason, play-ability.
Title: Re: Fuel Octane differences?
Post by: PR3D4TOR on April 17, 2017, 02:30:42 PM
I'd like to see 100/145 and 100/150 Spits and Ponies, but with a perk tag on them.
Title: Re: Fuel Octane differences?
Post by: Guppy35 on April 17, 2017, 02:35:18 PM
I'd like to see 100/145 and 100/150 Spits and Ponies, but with a perk tag on them.
And again this was discussed many times. I'm not saying not to talk about it. Just don't expect much to change if anything :)
First question I'd answer, is how would it benefit the game play? Why this fuel change, but not an LFVc then? You get the idea?
Title: Re: Fuel Octane differences?
Post by: PR3D4TOR on April 18, 2017, 04:55:39 AM
I would love to see the LF Vc back (preferably a clipped wing), as long as they keep the current Vb as well. The more the merrier. I've never understood people who argue against including something historically accurate to the game.
Oh you mean the documentation that showed that for a time 2/3 crashed on takeoff from the factory into the trees, making the people who built them sad?
Two thirds went off the factory runway into the trees you say? Documented. What was 'for a time' defined as? Months, days, minutes? And they also documented that it made people sad? How did they document their sadness? This is intriguing. Only Krusty knows such things :aok
Title: Re: Fuel Octane differences?
Post by: save on April 19, 2017, 05:08:11 PM
R4M for Me262 and Fw190's clusterbombs for Russian and German attack-planes.... 100 octane fuel 1940 during Bob for Bf109s for a slight perk cost.
Think about the new guys with no or few perkes, who already get clubbed, against some in here with 40k+ perk points to spend.
I would love to see the LF Vc back (preferably a clipped wing), as long as they keep the current Vb as well. The more the merrier. I've never understood people who argue against including something historically accurate to the game.
It isn't about arguing against. It's realizing you have to factor in the size of the company, the development time and priorities as well as game play for the newbies to the vets.
I've lived and breathed Spitfire XIIs since 1980. Would I love to have one in AH? Absolutely. Would it be the best use of resources and would it benefit the game? Probably not. Think of the howls now about Spit 16s which are nothing more than LF IXs with American made Merlins. Now add a 1943 low level beast in a Spitfire XII and they'd probably have the pitchforks and torches out for HTC.
Title: Re: Fuel Octane differences?
Post by: Oldman731 on April 21, 2017, 07:54:20 AM
How about a compromise and give the spits the option for the 45 and 90 gallon drop tanks- at least for scenarios.
Hah! Everyone knows Spits didn't have drop tanks!
- oldman
Title: Re: Fuel Octane differences?
Post by: Guppy35 on April 21, 2017, 11:05:18 PM
Funny part is that discussion took place a while ago. It was agreed the 30 was the best compromise as it was the standard tank once the Spits got the ability to carry DTs. :)
Title: Re: Fuel Octane differences?
Post by: thrila on April 22, 2017, 04:53:23 AM
Funny part is that discussion took place a while ago. It was agreed the 30 was the best compromise as it was the standard tank once the Spits got the ability to carry DTs. :)
The 30 gallon was the most common but the 90 gallon was certainly not rare. I'm not fussed for MA use, but it would certainly be handy for scenarios. I remember the thread discussing rationalising the spitfire tree in AH, i can't seem to find it though.
I've been listening to oral histories hosted on the IWM site (I would recommend listening to a couple, they're very interesting). I was listening Wing Commander Peter Parrott's WWII experiences recently and in one of his tapes he talks about how he pulled the lever so hard to drop his tank he broke it. :) It's about 3 hours long in begins with his experiences in France 1940 all the way up to his post WWII experiences. It can be found here: http://www.iwm.org.uk/collections/item/object/80012874 (http://www.iwm.org.uk/collections/item/object/80012874)
BTW this hijack was unintentional. Sorry. :D
Title: Re: Fuel Octane differences?
Post by: RODBUSTR on April 22, 2017, 05:16:10 PM
Virtually all the german planes were optimized to burn 87 octane that I know of.
Title: Re: Fuel Octane differences?
Post by: morfiend on April 22, 2017, 06:44:15 PM
Virtually all the german planes were optimized to burn 87 octane that I know of.
Hmmm what octane was the jet fuel? and what about the planes that used C3 fuel like the 190's?
:salute
Title: Re: Fuel Octane differences?
Post by: save on April 22, 2017, 08:32:04 PM
C3 was required for the 190, 109 could used with both b4 and c3, with MW50 injection octane levels increased on b4 fuel. About 2/3rd of German production 1944 was C3 fuel.
According to a British post war report (http://www.fischer-tropsch.org) German C3 fuel had properties closer to 100/150 than 100/130.
Title: Re: Fuel Octane differences?
Post by: Guppy35 on April 22, 2017, 09:50:43 PM
The 30 gallon was the most common but the 90 gallon was certainly not rare. I'm not fussed for MA use, but it would certainly be handy for scenarios. I remember the thread discussing rationalising the spitfire tree in AH, i can't seem to find it though.
I've been listening to oral histories hosted on the IWM site (I would recommend listening to a couple, they're very interesting). I was listening Wing Commander Peter Parrott's WWII experiences recently and in one of his tapes he talks about how he pulled the lever so hard to drop his tank he broke it. :) It's about 3 hours long in begins with his experiences in France 1940 all the way up to his post WWII experiences. It can be found here: http://www.iwm.org.uk/collections/item/object/80012874 (http://www.iwm.org.uk/collections/item/object/80012874)
BTW this hijack was unintentional. Sorry. :D
I corresponded with Peter Parrott back in the early 80s as he had some experience with the XII. An interesting man :)
The connection between the cockpit and DT in the Spit was not very sophisticated. One of the Spit XII pilots I got to know had the same thing happen in an XII. He pulled so hard on the DT lever it snapped. He let his squadron mates know he was going to have to belly in as the fuel tanks didn't switch over and he was dead stick. One of the other pilots told him to "Pull your wire man!" meaning take the actual wire running to the tank and pull it. Apparently it was also slang for playing with oneself. Tom responded "This is no time for jest!" as he glided down to become a POW.
The 90s were used for ferry flights and on a few occasions for long range escort later in the war. But the weight was so great there was always risk of blowing a tire, which some did. The 45 was used more often, but again, I think the decision to use the 30 was the most logical. It was the one used during 42-44 for cross Channel flights. With the Griffon birds due to the increased fuel consumption it was standard to fly with the 30 amd they often forgot it was on.
Title: Re: Fuel Octane differences?
Post by: MiloMorai on April 23, 2017, 01:16:24 AM
C3 was required for the 190, 109 could used with both b4 and c3, with MW50 injection octane levels increased on b4 fuel. About 2/3rd of German production 1944 was C3 fuel.
According to a British post war report (http://www.fischer-tropsch.org) German C3 fuel had properties closer to 100/150 than 100/130.
Early 190s used B4 fuel. It was from the BMW801D engine on that required C3 fuel.