North American Mustang Mk IV

The British Commonwealth provided the first Mustang orders to North American, and they continued to use the type to the end of the war.  But we normally see the late model Mustangs in US Markings.


After the jump, a brief look at a late model Commonwealth Mustang.

No. 3 Squadron of the Royal Australian Air Force spent the war attached to the Desert Air Force.  That means they started in Egypt, flying Gloster Gladiators; they re-equipped with Curtiss Tomahawks, then Kittyhawks as they moved in to Libya, Algeria then Italy.  And finally equipped with Mustangs in late 1944.  That’s a lot of combat. And with 217 air-to-air kills they were the most effective Australian Squadron of the war.


In the US Army Air Force, the only difference between a P-51D and P-51K Mustang was a Hamilton Standard propeller as opposed to an Aeroproducts propeller.*  In Commonwealth service both were classified as Mustang Mk. IV.  There were over 800 Mustang Mk. IVs, a majority with the Aeroproducts propeller which the Army Air Force apparently disfavored.

IMG_8812 IMG_8813

This subject is from the Hasegawa kit, with Red Roo decals.  The plane was flown by Squadron Leader P.M. Nash.  He is credited with adding the Southern Cross to the rudder of squadron aircraft, which was carried for the last six months of the war.



The Mustang on the left has the Aeroproducts propeller.  The one on the right has the Hamilton Standard propeller.  That is the total difference between these two aircraft. Is it more surprising that the US called one a "D" and the other a "K"; or that the British called both a Mk. IV?

The Mustang on the left has the Aeroproducts propeller. The one on the right has the Hamilton Standard propeller. That is the total difference between these two aircraft.
Is it more surprising that the US called one a “D” and the other a “K”; or that the British called both a Mk. IV?

* – Some sources claim the difference was if the plane was built in Burbank or Dallas; but this is not true.  P-51Ds were built at both plants.  But only Dallas took delivery of 1500 Aeroproducts propellers, and those are the Mustangs that were classified as “K” models by the USAAF.

File:P-51D 3 Sqn RAAF at Cervia 1945.jpg

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About atcDave

I'm 5o-something years old and live in Ypsilanti, Michigan. I'm happily married to Jodie. I was an air traffic controller for 33 years and recently retired; grew up in the Chicago area, and am still a fanatic for pizza and the Chicago Bears. My main interest is military history, and my related hobbies include scale model building and strategy games.
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18 Responses to North American Mustang Mk IV

  1. Theresa says:

    Interesting history of this air frame.

  2. Great job! I love the British scheme.

  3. Ernie Davis says:

    Whenever I think of the Mustang it is this model, the 51-D or K. Something I admit that I never knew about the plane.

    To me this is the plane that gave the allies air superiority.

    In 1943 USAAF’s theories of a self-defending bomber were being put to the test. And failing. Losses at some of the most ambitious raids were over 20%. In early 1944, as the mustang was finally becoming available in large numbers all that changed. The Mustang could escort the bombers all the way to the target and back, with supplemental fuel tanks on the wings. In addition Mustangs were being fitted with an additional fuel tank in the fuselage behind the pilot. This caused some real performance problems, but was determined to be worth it because they could empty that tank by the time the fighters would be engaged in combat.

    With the increased range Mustangs were finally able to engage German fighters over Germany as they intercepted the bombers. This lead to a need for the Germans to change tactics.

    The B17 and B24 are very rugged airframes, and to shoot them down the Germans had been relying on heavily armed and armored “heavy fighters” to inflict met of the damage. The heavy fighter concept had basically been disproven in the Battle of Britain when the German ME110’s proved easy prey to Spitfires and Hurricanes. The same was true over Germany with the Mustangs, so the very appearance of the fighter caused a change in tactics for the Luftwaffe.

    They first attempted to up-arm and armor existing light fighters, with some success, but while the German fighters (more the Bf190 than the Me109) were pushing their ceiling with the bombers, the Mustang was in their sweet-spot. This quickly led to a german tactic of massed formations of fighters cutting through bomber formations in a single pass before the Mustang escorts could react. Which in turn let to the tactic of “fighter sweeps” where the fighters went on the offensive, flew in ahead of the bombers, and cleared the airspace. It was this tactic, along with the decision to make fighters returning from escort duty ground attack units, that broke the back of the Luftwaffe by mid-1944.

    An unfortunate side-note was that the P51, with a liquid cooled engine, proved to be particularly vulnerable to ground-fire, and so the ground attack role was left to the robust P47 and the twin engine P38.

    Love the plane, love the build, love the history around this historic plane.

    • atcDave says:

      That would be Fw190 and Bf109; but otherwise, yes exactly!

      It was the P-51B (and identical C) that first took the fight all the way in to Germany. The long range fuselage tank was added during the production of the “B”. It did impact handling so severely (major CG issues) it was used to at least the halfway point BEFORE they even switched to the drop tanks.

      One of the more amazing things to me is the complicated ballet of the escort missions. Because not even the Mustang actually had the range to accompany the bombers on their whole mission. To fly all the way to Berlin and back the fighters would cruise at twice the bomber’s speed. So they had to spend a lot of the flight weaving so as to not get too far ahead.
      That meant the escort had to be provided in three or four phases during the mission. I can’t even imagine all the scheduling, route plans, rendezvous points….
      Fortunately a bomber formation is fairly easy to see, but keeping track of other escort groups, and who might be present at any given time, would be a virtual impossibility. And of course none of these guys had computer data base programs or GPS navigation. They didn’t really have any NAVAids at all over enemy territory; just dead reckoning navigation (fly a 080 heading for 90 minutes, then turn right 15 degrees… and hope the winds are close to the forecast…)
      So apart from fighting the deadliest air force in the world; they had to find the bombers, ensure more or less continuous protection on a 8+ hour mission from multiple fighter groups, and navigate cross country with minimal specialized equipment.

      And of course it took a while to get enough Mustangs too. Initially Mustangs might only fly one or two of the longest legs. Fortunately the Thunderbolt was reasonably long legged too, and could cover just over the German border. But what an amazing and heroic accomplishment.

      • Ernie Davis says:

        Yeah, can’t edit on this blog, and my desire to get my thoughts down sometimes gets the better of me. A habit I may need to break.

        But I agree with much of what you say. The tactical job, that they accomplished, is mind-blowing.

        Sometimes our iPhone hive-minds just can’t understand what our forefathers dealt with.

      • atcDave says:

        It’s pretty amazing what they accomplished without all our toys. My most recent car even has this automatic transmission thingy I don’t have to shift; we live in an age of miracles.

        Sort of a joke. They did have a K14 computing gun sight that was known as “the Ace Maker”. But of course that was analogue/mechanical computing,which makes even less sense to me than my transmission…

  4. John says:

    I have two questions I would like to ask about the Mustang. First, the Hamilton Standard propeller had a cuff on the inside third of the propeller blade. I always felt this made the Mustang look a little more macho. However, I have never been able to find out the aerodynamic reasons for having a cuff. Very few Mustangs flying today have cuffs installed, and I don’t recall ever seeing cuffs on the propellers of racing Mustangs. I sure would like to know what they are for.

    My second question concerns a small cross that is painted on the aircraft right behind the data panel. I always thought it meant that the fuselage fuel tank had been installed. Early Mustangs left the factory without a fuselage fuel tank and they were installed at the Depot level. A friend thought it indicated the center of gravity. I couldn’t see how this could be true because I had never seen the cross on any other Army Air Force fighter. Then lo and behold there is a cross behind the data panel on the ETO P38J. On the Lightning I will bet that the cross means that the dive flaps have been installed. I sure would like to know your opinion.

    • atcDave says:

      I’m not 100% sure, but I think the cuff is just to protect the base of the propeller. To keep dirt and stuff away from the mechanical parts in the hub. Post war, Hamilton Standard redesigned the propeller (blades at least, maybe the hub too) to be cuffless. By the Korean War, most Mustangs were using the Hamilton Standard cuffless propeller, and that is still true of most Mustangs on the warbird circuit. It’s pretty rare to see the WWII model of the propeller in use! But a few of the flying warbirds do use it.
      It’s funny because it is in issue in building anything other than a wartime “D” model. The two best kits available are Tamiya and Hasegawa. But Tamiya just has cuffed and cuffless Hamilton Standard blades with the kit. While Hasegawa has the cuffed Hamilton Standard, and Aeroproducts blades in their kit.

      The cross by the data block does represent a fuselage fuel tank, whether it was field or factory installed. It’s really just to draw attention to the fact from the ground personnel. I’m not sure on the P-38, my guess would be it’s the same sort of thing, some extra/optional system that needs periodic maintenance. The compressibility flaps are an excellent guess, they’re the only thing I can think of that were field modded in to a lot of early “J” Lighhtnings (and they were standard on late “J” and “L”). I’ll look later today and see if I can find an answer.

    • atcDave says:

      Okay, according to Larry Davis in “P-38 Lightning Walk Around” the “+” under a P-38 data block is extra 62 gallon fuel tanks in the wing leading edges.
      So its really almost exactly the same as the Mustang, its a slightly longer range mod.

  5. Pierre Lagacé says:

    Reblogged this on My Forgotten Hobby and commented:
    I missed that one Dave!

    Canadian Mustangs!

  6. Pierre Lagacé says:

    I stand corrected…
    Australian Mustangs.
    Got too excited.

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