Official Fulqrum Publishing forum - Just curious about the P-51 FM

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IIRC there were quite a few pilots that did not like the P-51 better than the P-40 or P-39. And didn't 56th FG willingly fly P-47 because they liked them more than the P-51?

The 56th FG stayed with the P-47 because Hub Zemke went on leave at a critical moment, and eventually moved on to take over the 20th FG in order to allow Dave Schilling to command the 56th. Zemke's memoirs state flatly that he would have converted to the Mustang quite willingly, because it allowed him greater access to the enemy. Despite several upgrades in fuel tankage, the P-47 never had the range of the Mustang until the N model, and all other things being essentially equal, he wanted to get at the Luftwaffe more than he wanted the PR of being associated with the Republic fighter. Schilling, on the other hand, was much more receptive to that sort of thing.

And didn't -I think- Bud Anderson state that the P-51 required trim adjustment all through the whole flight?

The often-repeated account of Anderson's dogfight tends to ignore that it took place at high altitudes, where trim and precise handling become much more critical in the thin air. Instead of "flight", the correct word is "fight"; as I have pointed out several times, had the Mustang been the sort of trim hog compared to its contemporaries depicted in this sim, the close formation form-ups through the typical British overcast that was necessary to avoid collisions would have been far more difficult and stressful (and probably much less successful). Every account of wartime Mustang operations stresses how easy it was to master the Mustang and exploit its capabilities, much like the Merlin Spitfire marques, the FW-190 and the F6F. The in-game versions of the Focke Wulf and the Spitfire are pretty easy to operate and to exploit their strengths; why are the Mustang and other late war US fighters so much more finicky and less responsive?

The P-39 though does require constant trim change in this game. The Bf 109 supposedly does not require much trim change -as it has no adjustable rudder and aileron trim -it was designed that way.

The P-39 does require more trim than the average fighter in the context of the game, but it was a small fighter with an unusual design; using up all your cannon ammo had a definite effect on your CoG, and you had to be alert to that. However, contemporary accounts make it clear that it was not remotely the trim hog that the P-40 was, and in the game, it is. The Bf 109 was supposed to be a delight to fly, and it was pre-trimmed for cruise speeds with the understanding that the pilot would compensate for extreme situations with his control inputs. However, getting it into and out of the air was known to be much harder than for most fighters of the period; even the Spitfire, with a similar landing gear layout, was far more benign. The 109's landing and taxiing issues are ignored in the game; it is instead one of the more tractable aircraft in the inventory, and even its late-war issues are not as great as I would expect from my own reading of LW pilot memoirs.

The P-40 in this game does not require trim change as much as it should need IMHO. And it is a extremly stable gunnnery platform, maybe a bit too stable.
Just speculation, but maybe the non-changing CoG could give rise to this behaviour?

Agreed; if anything, the trim behavior of the Mustang should be swapped straight across for that of the P-40M in the game. The Mustang's fuel tank layout is very similar to that of the P-40, except that the fuselage tank was added long after the aircraft's basic design was established; in practice, that tank was filled ONLY when the extra range it conferred was not achievable with drop tanks, and the aircraft obtained 'normal' handling characteristics as soon as the fuselage tank was even half drained. This has been used as cover for a systematic defamation of the Merlin P-51 for years now, to minimize its actual climb and acceleration vs its contemporaries by insisting that its overload configuration was only its 'fully loaded' configuration.

One can only speculate as to why people would insist upon only counting the overload configuration, but the initial (1943) appraisals of the Mustang versus the P-38 and the P-47 put it right in the same class as the P-38 as regards climb and acceleration without that fuselage tank installed (or filled, in later versions). There is an account somewhere in my extensive liberry that describes a competition between one of the top Lightning groups and a former P-47 group that had (finally) obtained P-51s; the argument was about which aircraft could get to 20,000 feet first, and finally the best pilots from each group met in head to head competition after many bets had been made and several gallons of ice cream had been obtained for the members of the winning aircraft's group. The P-38 won, but it was made clear that its pilot had used shall we say, "non-standard" procedures to barely make altitude ahead of the relatively green Mustang driver.

And yes I do think the plane models -even the late war US fighters- are fairly accurate and compare well to each other. This sim doesn't just give them the accurate historic context. Range and good serviceability don't count. Pilot quality is the same in the Axis and Allied camp while in real life at the time where the Mustang ruled the skies on average an Axis pilot was less capable than an US pilot. And US forces used superior tactics many times, trying to attack from favorable positions, trying to bring numerical superiority, and trying to cover each other.

Having 'flown' the FSX A2A version of the P-51D and the DCS Mustang sim, both of which are acclaimed for their accuracy, I can point out some basic differences between these and the Il-2 Mustang using CEM. I'll start with trim: A2A and DCS' P-51 do require some trim adjustment with power changes, but mainly for the rudder, and in tiny increments. It doesn't require an adjustment for every 5mph increase in speed, and the effect is felt instantly; the needle and ball wobble and fall into place--the real challenge is to apply the trim in small enough increments. Elevator trim is pretty basic, and in most cases, stick forces are so light that it is often easier to hold the stick back a touch than it is to fiddle with the trim wheel until you've reached the alt where you plan to fly straight and level, at which point very little adjustment is required. Aileron trim so far has been minimal; generally speaking it has caused me more grief to fiddle with it than it does to just leave it alone.

Acceleration and climb; with the fuselage tank empty, once airborne, you can set your Manifold pressure to around 45" and the prop pitch for 25-2700 rpm, and you will be doing 250 mph (and climbing) before you can say "Bob's your uncle". Put your nose down and you pick up speed very quickly; without having the 'Zoom' set on my CH Throttle's microstick for the DCS version (to make up for my nearsightedness--I have to get a prescription just for midrange vision, instead of trying to see through a microdot on my trifocals), I'd be up over 450 mph at lower alts all the time--you have to watch your speed to keep it down to manageable levels, not constantly struggle to get it up and maintain it.

A2A and DCS versions are harder to take off in and easier to land than the 'simplified' Il-2 version; it took me about 3 1/2 hours of effort and fiddling with my rudder curves before I could get the DCS Pony into the air, but on the second time I got it off the ground successfully, I made a landing following what I remembered from the original MS Combat Air Simulator procedure; it worked like a charm. The next time I tried it, I spent a good hour doing touch and goes, sometimes giggling like a little girl, it was so much fun.

A2A and DCs depict the Mustang as a very responsive aircraft with predictable responses to pilot input; as long as you pay attention to what you're doing and avoid any sudden jerks or uncoordinated inputs, the Mustang will do what you want it to do; obviously it is much faster and better climbing than the Il-2 depiction, and the trim is quick to respond and predictable. It won't turn on a dime, but at 270mph indicated (which it can achieve and hold with shocking ease) the record shows that it would outturn most everyone else at the time without losing speed.

Had the US in the late war faced an enemy that could bring equal numbers of planes with enough fuel and equally capable pilots, using the same tactics the US did (reflecting the situation in this sim), they would have suffered considerably.

Now, about context, let's examine the period when the Merlin Mustang was introduced into combat; from November 1943 until April of 1944, there were only between one and three groups of nominally 50 fighters flying the P-51B/C. Besides the two P-38 groups, which had some even more serious maintainability issues and the marked inability to pursue an opponent in a high altitude dive, these were the only fighters in the Allied inventory that could reach into German airspace and escort the bombers during that period. Doctrine at the time required close escort, and there were a number of maintenance issues as well that led to most if not all escort missions being shorthanded during those months. In addition, two of the first three fighter groups assigned the Mustang were rookies; they had a few combat veterans in leadership, but more than three quarters of them were fresh off the boat from training commands. Only the 4th FG had any meaningful combat experience at the unit level, and they didn't get to join in the festivities (Mustang wise) until after Big Week in late February of 1944.

So here's your context: outnumbered in German airspace by over four to one by single engine German fighters over Germany, closely tied to the bomber stream, less than 150 fighters inflicted enormous damage to the Reich Defense fighters; from December 1943 to the early parts of April 1944, the Luftwaffe suffered an unprecedented loss of experienced leaders in its fighter corps, mostly right over Germany itself. The fuel supply at that point was not severely constrained and the German fighter pilots couldn't complain of exhaustion at that time, because the pace of Allied bombing over Germany had slacked off considerably during late 1944 until late February due to casualties to the bomber groups and the bad weather most of that winter, and the bald fact is that the Jagdewaffe was vastly more experienced and in large part just as well trained as the Americans in the Mustangs at that point in the war.

And the German pilots had not arrived in the combat zone after two or more hours of flying at high altitudes mostly over enemy held territory with their heads on a swivel in what was still essentially an experimental aircraft with a single engine that was known to occasionally pack it in over that enemy held ground or the North Sea in winter. The issues with the gun ammo feeds was quickly identified, although it took a while to fix and for the word to get around--communications were not as easy or simple as we take for granted today. The Germans were flying excellent aircraft with proven combat records and armament, well known established tactics and doctrine, with superior numbers, knowing where the enemy formations were before they took to the air, over their own territory, defending their homes--and they took a whipping.

After which, the Mustang pilots still had to fly two or more hours over enemy held territory to get back to southern England, where his base could easily be socked in by fog or heavy weather (I lived there for four years--I've seen it).

The greater numbers and superior training factored in after that point in mid-April 1944 as a direct result of the largely Mustang-inflicted casualties and the 8th AF started targeting the oil refineries in a serious way after D-Day; the Mustang was finally being produced in sufficient numbers that they could replace combat losses and equip other groups (and except for the 23rd FG in China, it was another four months before the Japanese saw a Merlin powered Mustang) and other veteran groups could convert from the P-47.

The obvious conclusion is that the P-51 was a much better than average fighter aircraft for that period in most respects, not merely range and speed. Admittedly, the opposition was hamstrung by not having a precise appreciation of what it could or could not do compared to their own aircraft, but that sword cuts both ways in war. In-game, the P-51 is slower to accelerate, harder to keep trimmed (which forces its virtual pilot to ahistorically fight his stick most of the time) and generally difficult to master compared to its opposition, which runs counter to both the record and other simulations that are widely acknowledged to be accurate.

The Mustang is not the only aircraft affected. All of the late war US fighters started experiencing 'issues' after the fracas over rights with the defense company that shall not be named; there was a steady series of problems with trims, the notorious wobble, fifty caliber convergence and the business about uneven firing synchronization of certain Allied aircraft since then. At some point, Oleg and the boys need to get over it.

cheers

horseback