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The link I sent you was listing internal fuel for all models of A6M along with the capacity of the typically used drop tank.I didn't mention external tanks, Ivan. The 134 gallons above is all internal. It is also A6M3 Model 32.
I can certainly find out the fuel capacity for the A6M5 Model 52 since we fly one, but I'd not bother the people about it until the airshow was over ... which it was 2 weeks ago. So, this weekend is a good time to ask and we HAVE the information if only the correct people are around on Saturday.
Regarding the use of settings above their "Military" rating, we have the claim by Mr. Saburo Sakai of the A6M2 being able to achieve 345 MPH on "Overboost" setting.
We also have corroborating evidence in the third of the reports posted by R Leonard (SWP Report).
Read the comments section.
The Sakae was apparently a well built and tough engine as later TAIC reports about "Flash Performance" from Oscar and Mr. Sakai's encounter with a squadron of Hellcats would seem to indicate.
This particular report and most others that show some detail on Koga's rebuilt A6M2 seem to indicate that all was not right with the carburetor.
There are comments showing a bit of surprise when thing appear to be running correctly. There was also a mention of the automatic mixture control not actually working. I believe this was by Corky Meyer. The pilot found that after a bit of climbing, the engine was starting to misbehave until it was leaned out.
This particular engine had spent a month with part of it underwater. When rebuilt, it had to have a couple cylinders resurfaced. I do not know whether the carburetor was also underwater.
In many of the test reports on Koga's A6M2, the critical altitude seems a bit too low and for some reason they are running the engine as if they believe 2550 RPM is the proper limit.
I don't recall ever seeing a test run at 2600 RPM, so if you know where I can find that, I would appreciate it. There was speculation that 2600 RPM was the limit but I haven't actually found a test report showing this was done in a test flight.
Regarding 60 inches of boost on the P-40E at altitude. I believe you are being VERY optimistic. This level of performance was more characteristic of later Allison engines that did not run out of breath quite so low.
Regarding fuel loads: Spitfire and Me 109 both had just over 100 US Gallons of internal fuel. Both were also known for having very short ranges. What I found interesting was that Hurricane wasn't that much better at only 116 Gallons. You wonder why US was complaining about the Airacobra with 120 Gallons.
Of the reports, the 141 Gallon internal fuel load for A6M2 is closest to correct. It should really be about 141.3 US Gallons or 480 Liters nominal.
I looked through the report you provided a link for.I've read other things that Sakai has said in his memoirs about fuel consumption and ranges etc, and he does seem to have a good recollection of numbers.
But tuning simulation models based on pilot quotes alone is risky business just for the reasons tyrodtom mentioned in his post above. In addition, IAS read off on a dial in a cockpit need to be converted to CAS and the POC can be quite large in some cases.
This test of Koga's Zero you mention, which one was it? There are a number of different Allied trial reports on the Zero and I'm not sure which test you are referring to?
I include a screenshot below from the Wright Field test I mentioned earlier in which they ran the engine at 2600 rpm. You can find the complete report with speeds, climb rates and technical data from that test here:
http://www.wwiiaircraftperformance.org/japan/a6m2-oct2342.pdf
View attachment 799327
That should have been 535 Liters.Regarding the use of settings above their "Military" rating, we have the claim by Mr. Saburo Sakai of the A6M2 being able to achieve 345 MPH on "Overboost" setting.
We also have corroborating evidence in the third of the reports posted by R Leonard (SWP Report).
Read the comments section.
The Sakae was apparently a well built and tough engine as later TAIC reports about "Flash Performance" from Oscar and Mr. Sakai's encounter with a squadron of Hellcats would seem to indicate.
This particular report and most others that show some detail on Koga's rebuilt A6M2 seem to indicate that all was not right with the carburetor.
There are comments showing a bit of surprise when thing appear to be running correctly. There was also a mention of the automatic mixture control not actually working. I believe this was by Corky Meyer. The pilot found that after a bit of climbing, the engine was starting to misbehave until it was leaned out.
This particular engine had spent a month with part of it underwater. When rebuilt, it had to have a couple cylinders resurfaced. I do not know whether the carburetor was also underwater.
In many of the test reports on Koga's A6M2, the critical altitude seems a bit too low and for some reason they are running the engine as if they believe 2550 RPM is the proper limit.
I don't recall ever seeing a test run at 2600 RPM, so if you know where I can find that, I would appreciate it. There was speculation that 2600 RPM was the limit but I haven't actually found a test report showing this was done in a test flight.
Regarding 60 inches of boost on the P-40E at altitude. I believe you are being VERY optimistic. This level of performance was more characteristic of later Allison engines that did not run out of breath quite so low.
Regarding fuel loads: Spitfire and Me 109 both had just over 100 US Gallons of internal fuel. Both were also known for having very short ranges. What I found interesting was that Hurricane wasn't that much better at only 116 Gallons. You wonder why US was complaining about the Airacobra with 120 Gallons.
Of the reports, the 141 Gallon internal fuel load for A6M2 is closest to correct. It should really be about 141.3 US Gallons or 480 Liters nominal.
I looked through the report you provided a link for.
I see the mention that the propeller settings would allow for a maximum of 2600 RPM, but there is nothing in the actual speed runs that states that was the RPM being used.
As for Sakai and his statement of 345 MPH on overboost, what would that look like to an opposing pilot?
How about this: (from comments in SWP report)
Comments: Mention is made of a form of automatic boost control which limits
the manifold pressure to 35". Further mention should be made here of the fact
that there is a manual over ride which permits the manifold pressure to exceed
35" and obtain maximum boost from the engine. It is thought that this gives
the dense black smoke reported often in combat in connection with unusual
bursts of speed. In some instances this smoke has been attributed to injection
of some chemicals but it is felt that this is the result of of the manual over ride.
The section following this describes messing with the propeller pitch range to try to get the engine to wind up the way they were expecting.
The difficulty here is suggestive either of a propeller that is overly large or non-optimal gearing for the engine or an engine that isn't achieving the torque that it should be.
I've been shot at in a chopper, actual combat, and it's pretty stressful.
I've also circle track raced myself from 1996-2016, helped and spotted ( radio) for other racers at NASCAR, ARA, and other tracks from 1990-to present.
I won't say racing is as stressful as combat, maybe a 6 on a scale of 10.
But I've noticed I can't or any other racer I've been around can keep track of what lap they're on without outside help, like seeing the lap number on the score board, you're exsisting in the second, using every sense you have just to keep the vehicle under control till the next second, you can plan ahead, to some extent, but your mind is in survival mode, not record mode.
When it's over you remember some, but jumbled sometimes, out of order.
One of my early sponsors was a guy that videoed every race. He gave me videos of every race I was in.
Later I would watch those videos, and realize sometimes I didn't remember things in the way they actually happened.
And that's not unique to me alone.
For years afterward we also had GOPRO recorders in the car also.
The human mind is just not equipped to record accurately under stress.
They're not cameras, they're not recorders, they're not computors, they're humans beings.
Maybe rare individuals can, but they're very rare.
So rare I don't think I've ever met any.
Some of you seem to believe perfect recall, of events that happen 50-60, maybe even 70 years before.
I notice the pilot said he circled PROBABLY 75-100 circles. A big variation, and then there is that "probably".
I know most aircraft of that era had clocks.
How many pilots do you think wrote down the time when they entered a dogfight, and again wrote down when it ended?
I think we all know it's just a guess.
I read hundreds of books too, on aerial combat, watched many videos, but I've always realized they're just memories of a human mind.
My dad, and two of my uncles were WW2 Marine veterans, all fought in the Pacific.
We had some interesting family get togethers, this was in the 50's early 60's, I'd try to soak up all they had to say.
I was in my early teens, they were in their late 30's or 40's, about 15-20 years since the war.
Even then I could see that some of their recall of events getting meshed, re-arranged, that they didn't have perfect recall.
They were my heroes , but they were still human.
If he didn't or couldn't keep count of how many turns he made, it's just a guess.His inaccuracy under stress is taken into account by him, which is why he says 75-100 circles.
All of you, on the other hand, have trouble figuring out how this is possible, because you had no conception of the "no rolling out" rule, without which you can have no understanding of why that situation was the way it was.
You don't have the most basic understanding of the facts, and are dismissing the account of a P-51 ace because it doesn't fit your understanding of how WWII turn fighting worked.
You also have likely not read 1/10th of the combat accounts I have read, which allowed me to collect the 3 general quotes concerning how rolling out was "stupid" "fired short bursts to try to get him to roll out, but he was too smart to do it", and "the majority of our kills were made good when the kraut reversed his turn: NEVER REVERSE YOUR TURN."
Pilots of the time will rarely disrepect an opponent by calling his actions stupid. They will do it only if it is an eggregious error. The fact you are unaware of this simply demonstrate your lack of first hand knowledge.
So there is no need to pontificate on vague generalities about the fallibility of human memory. That is not the source of the problem here.
The fact you are unaware of this simply demonstrate your lack of first hand knowledge.
Technical Aviation Intelligence Brief No. 3 in paragraph 4 states 2550 to 2575 RPM was used for testing.Now that there, is some very creative reading of the wording in the report which is this:
"NOTE: For these tests the propeller setting used permitted a maximum RPM of approximately 2600 and the manifold pressure is automatically regulated to 35" below critical altitude."
In addition, even the SWP report you yourself refers to, both under "Comments" and "ENGINE" mentions that the estimated rated rpm was 2600.
Well in the SWP report they also mentioned that the BUAER tests were not completed at the time the report was compiled, and this of course opens up the possibility that it was mentioned somewhere else in a later report. And for sure, if there was such a manual override and it could increase boost, say from +150 mm to a WEP of +250 mm (which as I understand it was the take-off boost?), then an increase in speed from the 335 mph at 35" (+150 mm) boost would of course be quite feasible.
But do we have any such data? Was it for example possible to go to +250 mm at the FTH? And if so, for how long could you run it like that? 1, 5, or 10 mins? Until we know, the best I've seen so far is the 335 mph at 16,000 ft with 35" and 2600 rpm. However, if some new solid data emerges suggesting a WEP setting with +250 mm or something else, then that would of course warrant an update of the modeling for me.
His inaccuracy under stress is taken into account by him, which is why he says 75-100 circles.
All of you, on the other hand, have trouble figuring out how this is possible, because you had no conception of the "no rolling out" rule, without which you can have no understanding of why that situation was the way it was.
No need to pontificate? No need to pontificate!?..So there is no need to pontificate on vague generalities about the fallibility of human memory...
Hear! Hear!No need to pontificate? No need to pontificate!?
Pontification, Sir, is the primary force that awakens me from slumber! Pontification is the glue that bolts together the tapestry of communication. How else might one bring enlightenment to those foundering on reefs ignorance? How may misguided intellects cast upon on the shoals of ignorance find guidance without our bonfires of brilliance? When one has achieved enlightened insight, without the distraction of peer review, it must be told. Nay, it must be broadcast. Broadcast I say! Through all means possible. If anonymous web sites, forums, local newspapers or crudely posted handbills are required, then they must be used. From early human beings gathered around fires, the village wisemen, shamans, alte kakes and yentas have had to bring understanding to the hidden truths hidden from those using simple logic or truth. I myself have had to expound frequently and at length despite just enjoying hearing myself talk. It would be negligent of our moral compasses not steer our blithely ignorant fellows to chapel of smart. Standing on the soapbox of awareness, it would be shameful, nay, a sin to not clear the mists of obviousness of incoherent thought. Anyone still reading this drivel? Pontification is an unstoppable force of the irresistible nature of ignoring whatever anyone else may care and just keep blathering away until they get your point. Or just the enjoyment of hearing oneself talk. Pontification is not only a sacred freedom enshrined in the constitutions of our foremost nations as well as most public lavatory walls. It therefore cuts across all social and economic strata as the gift of education, asked for or not! I do not know your beliefs, Sir, but I believe in these sacred freedoms. I believe in the Constitution of the United States, the Magna Carta and the Rights Of Man. Give me pontification, or give me death!
I looked through the report you provided a link for.
I see the mention that the propeller settings would allow for a maximum of 2600 RPM, but there is nothing in the actual speed runs that states that was the RPM being used.
As for Sakai and his statement of 345 MPH on overboost, what would that look like to an opposing pilot?
How about this: (from comments in SWP report)
Comments: Mention is made of a form of automatic boost control which limits
the manifold pressure to 35". Further mention should be made here of the fact
that there is a manual over ride which permits the manifold pressure to exceed
35" and obtain maximum boost from the engine. It is thought that this gives
the dense black smoke reported often in combat in connection with unusual
bursts of speed. In some instances this smoke has been attributed to injection
of some chemicals but it is felt that this is the result of of the manual over ride.
The section following this describes messing with the propeller pitch range to try to get the engine to wind up the way they were expecting.
The difficulty here is suggestive either of a propeller that is overly large or non-optimal gearing for the engine or an engine that isn't achieving the torque that it should be.
You kind of need to know the rest of the context of the discussion.Or the prop rpm being limited deliberately so that the blade tips did not exceed the speed of sound and lose thrust. (and that may have been because of an incorrect reduction gear ratio or it also may have been deliberate to get the great fuel economy the A6M is famous for)
Of course, without all the tech manuals and instructions, it is likely that the engine and prop set-up was not all at optimum. However, the early counterweight/hydraulic HS copy prop was limited to 20 degrees of pitch range and that is insufficient for full rpm control of a high speed 300mph+ fighter. The small available pitch range means that the installed prop setting will have to be set slightly coarse for minimum pitch stationary on the ground. This setting will not be excessive as it will reduce rpm and power at Take-off. However, for carrier operations, the Wind over the deck will see the blade angle rapidly match the required rpm. The 25 degrees min blade angle setting roughly matches this.
The max blade angle of 45 degrees is not sufficient for high speeds, especially in dives, and this is reflected in the write-ups of overspeeding in dives.
So, overall the reported "problems" with not quite being able to achieve full rpm on the ground will match the limitations of the prop pitch range. However, the inability of achieving the full 2600 rpm in flight with an engine running well would indicate the prop pitch controller or its rigging was incorrectly set or malfunctioning at the 2600rpm selection.
Eng