John T. P-51 A,B,C & A-36 with Org. Wing, or Modified "D"

[Triplane102]

John Terrell, Could you please list the surviving P-51 A, B, C, & A-36 with Original /' Type " Wings & those with Modified " D " wings, I was reading how P-51 C " Thunderbird " will use a Modified " D" wing for safety reasons, but will slightly alter the Underside of the lower cowling. Thank You in Advance,

[JohnTerrell]

All of the examples of those types flying today have the original early type wings except for Dusty Dowd's (beautiful) P-51A 43-6006, which, including after its recent restoration at Pacific Fighters, retains the D wing. Back when Moon Spillers built up that aircraft, it was primarily based on an existing D model airframe, both wing and fuselage (from the upper longerons down). Uniquely, on the Collings Foundation's 'TP-51C', which does have the early type wing and landing gear geometry, the inner workings of the main landing gear doors and locks are D model, rather than the earlier A/B/C setup.

[Snake45]

Uniquely, on the Collings Foundation's 'TP-51C', which does have the early type wing and landing gear geometry, the inner workings of the main landing gear doors and locks are D model, rather than the earlier A/B/C setup.

I noticed when I saw it a couple years ago that it had a D landing light, and wondered about that.

[Dan K]

And perhaps we can start calling Dusty Dowd's 43-6006 what it really has evolved into:

The XP-51A/D

(Tin hat on and trench gun locked & loaded)

[JohnB]

Not being a in-depth Mustang expert, I noticed some unexpected things when looking at the Historic Flight Foundation's B "Impatient Virgin".

Under the right wing are three colored signaling lamps.
I'm pretty sure"D"s don't have them.

Also, the wings only have two guns, not the more common three gun setup.
Finally, the bomb/drop tank racks are seemingly added on black units, not the more streamlined silver units seen on Ds.

I assume all these changes are correct for the type since it was built by Pacific fighters and has won an award at Oshkosh.

[Kyleb]

The thread begs the question "So what are the major differences between the "D" wing and the prior wing(s)?" I knew they had changed the gear uplocks, but beyond that...

[JohnTerrell]

The most significant difference between the A/B/C wing design and that of the D wing design was the inner most leading edge "triangle" section (the area from the landing gear pivot shaft casting to the fuselage). As a result, the lower engine cowlings and fairings are of different design too.

There are of course other details that are different, but have nothing to do with the overall geometry of the wing (they only matter if you really care about the intricate details):

- the landing gear retract geometry is different between the A/B/C and the D, and the landing gear doors are different as well (the landing gear legs themselves are the same)
- gun ports - two recessed on the A/B/C vs. three that protrude on the D wing
- bullet shell and link ejector chutes - these are of course different, as seen on the lower sides of the wings, below the guns
- gun bay doors - many changes to the gun bay and ammunition bay doors, even up through the various D model production blocks (the D models themselves had three different types of ammo bay doors throughout D production, and two different styles of gun bay doors)
- landing lights - mounted in the leading edge on the A/B/C wing, vs. lowering from the left wheel well on the D
- wingtip nav light locations - on a stock A/B/C wing, there is a nav light on the top and bottom of the outboard wing extension - on the D wing/wing tips, there is a single nav light positioned out on the far edge of the wing tip (some of the A/B/C variants flying today have D model type wing tips - the geometry is the same, just the location of the nav lights is of the D-type, rather than the earlier A/B/C)
- recognition lights location - they all had them, the three lights (red/green/amber) positioned under the outboard right wing extension - on the A/B/C wing, they are farther inboard within the wing extension than they are on the D wing
- different number of external wing stiffeners (located ahead of the ailerons) depending on production model/type
- the fairings covering the bomb release shackles are quite different between the A/B/C generation aircraft and the D
- the pitot tube mounting assembly is different between the A/B/C and the D

As mentioned earlier, there is also quite a bit that is different inside the wheel wells on the A/B/C vs. the D.

One of the greatest Mustang myths, and which is completely untrue, is the often repeated claim that the D model wing was made thicker in order to mount the machine guns upright - that is completely false! The thickness of the D wing is no different than that of all of the Mustang wings going back to the earliest production example, the Mustang I. The fact that the machine guns were canted on the A-36 and P-51A/B/C variants, was that it was a leftover concept from the earlier NA-91 (P-51-1-NA/F-6A) design, which had 20mm cannons, that had to be mounted at an angle in order to fit. When the A-36 was being devised, following the NA-91/P-51-1, the Army wanted to keep the option open for either continuing to use four 20mm cannons or to go with four .50-inch machine guns - ultimately they of course would go with the four machine guns, and the mounting setup remained as it had been with the cannon installation. The P-51A then followed the A-36. By the time combat reports were coming in from pilots experiencing gun jamming with the P-51B/C, which still had the guns mounted at an angle, the NAA engineers had already been working on the new D wing armament setup, in which they were able to mount the machine guns upright, without having to change the geometry of the wing.

Here's a quick comparison between a stock A/B/C wing and the D wing, pointing to the only real significant difference between them. Pilots that have flown both comment that the earlier wing stalls ever so slightly faster than that of the D wing. The firewall location (panel seam between the fuselage and engine cowlings) is the same.

Last edited by JohnTerrell on Mon Aug 09, 2021 5:15 pm, edited 2 times in total.

[Jesse C.]

This is some great information! Thanks for explaining it, John T!

[JimH]

By the time I had the opportunity to fly a D model I already had 4 years of flying Betty Jane under my belt. I was really used to the B/C. I've sat in countless D models over the years and bought backseat rides in 13 of them prior to us getting Betty Jane. But, never flew a D from the front seat until 2013. The cockpits feel completely different. The B is more reclined and there is a lot more distance between the panel and the seat. The trims are easily accessible with the T-6/early Ball type throttle quadrant. The canopy is restricted in a couple ways. It takes a while to get used to the birdcage, but after a while you don't even notice it. You can't open it in flight, and if you open it on the ground with the engine running you are putting your life in the hands of the crew chief when it blows off the airframe . I never tried opening the side sliders in flight, it didn't really matter, it was hot no matter what was going on. Flying, it is a tad faster than a D at the same manifold pressure in cruise, and that can probably vary per airframe. I found that landing the B/C took a couple extra miles an hour over the D. I don't know if that was due to the extra weight of the turtledeck and/or the extra weight of the rear cockpit? It will still 3 point beautifully, just a tad faster. It really drops out of the sky if you get it below 110 on short final, but once you transition in to ground effect it's a pussycat and slows right down.

Getting in the D the first thing I noticed was how close the panel and front cockpit windscreen were positioned. The other thing is the massive throttle grip jutting out from the left longeron. The entire quadrant is deep enough that it makes getting to the Rudder and Elevator trims awkward. After a about 15-20 minutes you get used to it, it is just different. The D seat feels, to me anyway, a bit more upright and not nearly as reclined as the B/C. Landing the D is night and day over the B/C, you can actually see where you are going and it rounds out to a tail low touchdown with almost no effort.

Flying and acro feel the same, speeds are the same, power settings are the same...they both fly on rails, nothing else like it.

John T is correct about the wings. Chris Fahey at POF took a ruler to the A,B, and D...there are some minor differences in the doors but overall the ammo bays are he same. Also, we had some damage to our right flap a few years ago. I ferried the airplane (with a permit) to FL for repairs. American Aero hung one of Toulouse Nuts flaps on to get us through the season...so the parts are interchangable. Hope this is informative.

Jim

[Lynn Allen]

Thank you John for the intel.

[Triplane102]

I know I mentioned "Thank you in advance ", BUT I REALLY have to say Thank You ! Again ! to John Terrell, There are Tons of great post here on Wix, with lots of interesting History, backed up by great photos, But I find Just the Knowledge you have, Sir, on Warbirds & Especially on the P-51, to be Interesting and educating . Thanks also, to Jim H., Great to also have input from one who who has been at the Stick of these Great Birds. Thank You Sirs !

[sandiego89]

Thant you John and Jim for the great insight and explanations. Always like to hear about subtle differences in how models are designed and the pilots perspectives. Neat stuff!

[sandiego89]

Thant you John and Jim for the great insight and explanations. Always like to hear about subtle differences in how models are designed and the pilots perspectives. Neat stuff!