Acceleration comparisons

[JtD]

You'll need to engage low gear (2nd stage in game) in order to get any benefit from water injection. Both with and without water injection you're operating above full throttle altitude, where the benefit of water injection is nearly zero.

I would like to know what your "generally accepted" speed performance figures for the Wildcats are. I can tell you right now that they match or exceed the figures given in Americas 100000 as well as the figures quoted on ww2aircraftperformance.com.

F6F and F4U performance is modelled for clean aircraft.

[horseback]

Originally Posted by JtD

You'll need to engage low gear (2nd stage in game) in order to get any benefit from water injection. Both with and without water injection you're operating above full throttle altitude, where the benefit of water injection is nearly zero.

I would like to know what your "generally accepted" speed performance figures for the Wildcats are. I can tell you right now that they match or exceed the figures given in Americas 100000 as well as the figures quoted on ww2aircraftperformance.com.

F6F and F4U performance is modelled for clean aircraft.

The 'HUD' message telling you that water injection is engaged goes up even so. Who knew that the game would lie to me like that?

As mentioned in an earlier post, ww2aircraftperformance.com shows a test for the FM-2 with a level speed at 5000 ft of 312 mph true (502 kph); an F4F test for 4600 ft shows a true airspeed of 283 mph (455 kph).

Attached is a blowup of the chart from America's Hundred-Thousand for the Wildcats' various models' Speed and Climb performance, scanned from the book and then printed on graph paper in the forlorn hope that it would be made a bit clearer (Murphy made his usual appearance, alas). The FM-2's speed graph line is highlighted in pink, the F4F-4 is in blue and the F4F-3 is in green. As you can see, the FM-2's line at 5000 ft is clearly east of the 300 mph line, while the F4F-3/-4's lines are well to the west of it, around 285 mph.

I used the same references you claim you used.

cheers

horseback

[JtD]

The HUD tells you the water injection is active because it is. It works above full throttle altitude. It did in real life. There's just no increased boost any more, and therefore there's no meaningful extra power. As it is in real life.

In game, the F4F manage around 295 mph at 5000ft. So clearly, the Wildcats do not "fall well short of generally accepted performance figures". Two of them are clearly overmodelled, and one of them falls "somewhat" short of generally accepted performance figures, and that not even at all altitudes. Unfortunately though, at the important ones.

[Woke Up Dead]

Originally Posted by JtD

The HUD tells you the water injection is active because it is. It works above full throttle altitude. It did in real life. There's just no increased boost any more, and therefore there's no meaningful extra power. As it is in real life.

I think IL2 Compare helps you figure out at what altitude boost no longer makes a difference. There are two lines on each maximum speed graph: the speed at 100% throttle, and the speed at 110%/boost. In some planes, like the Hurricane and Spitfire, the two lines meet at 4-5000m.

[horseback]

Originally Posted by JtD

The HUD tells you the water injection is active because it is. It works above full throttle altitude. It did in real life. There's just no increased boost any more, and therefore there's no meaningful extra power. As it is in real life.

In game, the F4F manage around 295 mph at 5000ft. So clearly, the Wildcats do not "fall well short of generally accepted performance figures". Two of them are clearly overmodelled, and one of them falls "somewhat" short of generally accepted performance figures, and that not even at all altitudes. Unfortunately though, at the important ones.

I used the term 'well short of accepted figures' for the Navy fighters as a group, which was a bit sloppy of me. The Wildcats are, however, shockingly sssllllloooooowwww by any measure; over 10 seconds to gain a bit over 6 miles an hour can seem like hours after testing the Corsair at sea level. When you're struggling to maintain level flight by detecting whether the altimeter needle is moving (the variometer is at least a second behind the curve), the intervals take forever to go by, and when you finally reach the point where there just ain't no more, you glance at the speedbar and think "WTF?"

Even if they are about 20 kph faster than they should be, that impression is hard to shake.

In any case, the FM-2 is poorly represented, and if former pilots' direct testimony to me is to be believed, the tall-tail Wildcat could accelerate with the Zeros and Oscars they encountered in the Marianas and the Philippines (the old guys picked out all of the Japanese fighters from my then-extensive collection of 1/72nd scale models and named each one --and corrected some of the color choices I made). Even accounting for the usual hypercompetitive BS factor present any time Navy veterans of any age meet, that means that like its climb, the FM-2's acceleration should be pretty good as well, even if measured against beat-up, poorly maintained A6M5s of the later war period. My former landlord said (realizing for the first time that my wife was present) that the FM-2 was "a he-heck of a lot uh, peppier than the Dash Fours or even the Threes."

If it was anything like the one we have in Il-2 '46, there wouldn't have been three 70-something year old men in my living room that day in 1985.

cheers

horseback

[horseback]

The document above states: "Rudder trim effectiveness was not sufficient to trim in the high power climb." If I get this correctly it means though FULL rudder trim was applied in a high power climb the plane still deviated from flying straight. So at least early F6F-3s were trim hogs in rudder when climbing with full power - and I doubt that later model F6F behaved much different - even if a larger trim tab or different rudder were added, changing from clevel flight to climb would still require lots of trim change in rudder.

If you read my post containing the trim sections from America's Hundred Thousand, you'll recognize the passage below:

"There were nose up trim changes with gear and flap retraction, though they were minimal, and the same was true of initial acceleration into climb. In general, there were substantial both directionally and laterally with speed and power changes, but tab action allowed trimming out control forces to zero except for the rudder. At low speed and high power rudder pedal force could not be trimmed out fully. Most pilots thought trimmability was generally good, though some made the following comments ‘Lack of trimmability”, Excess rudder trim change”, and “Aircraft requires excessive trim” (three pilots). It was noted that in a dive control forces could not be trimmed out quickly enough."

Trim adjustment was a relatively new practice in military aviation in the early 1940s, and most American fighters appear to have had some points in their performance where full trim input did not completely wash out the need for a bit of rudder input, or where it couldn't be input as quickly as the demand increased. The extra amount of right rudder needed didn't result in the unbalanced muscular deformities claimed by long-time P-40 or Bf 109 drivers, so it wasn't a severe problem, but it was something that wasn't supposed to be there, according to either the original request for proposal or the resulting contract language for the F6F-1.

The phraseology used sounds like a standardized bullet point in the test documentation to my long time government contracting ears; I would expect that that phrase, or some minor variation of it is found in almost every Hellcat acceptance test document. Without it in there, a battalion of government bureaucrats would have had a near fatal case of the vapors, and the US war effort might have ground to a complete halt.

As I pointed out, the FW 190A and Bf 109 lacked any in-flight trimming capability for their rudders, even though rudder had to be added or subtracted as attitudes and speeds changed; does that mean that they were 'trim-hogs' in the rudder department too? I know that US pilots doing comparison tests of German aircraft were quick to criticize that particular feature of those aircraft, but that it didn't seem to limit their combat effectiveness.

So it was with the Hellcat.

I'll try using the second stage of supercharger with the Hellcats and Corsairs as you suggested; if the results are significantly better with the initial test runs, I'll revise the charts.

cheers

horseback