P-51 Design Analysis

[BiffF15]

Pete,

He probably could look under the tail a bit because with the Malcom Hood his pumpkin was basically out in the slipstream area. The D model in my opine was better as it allowed you to check six much easier in a turning fight. To check under your tail just wag the rudder pedals, plus have your wingman out in a tactical line abreast or close to it position so he can each check the others six o'clock.

Plus the D gives you two more (and more reliable) guns. More is better most of the time.

Look at modern fighters. The F-16 has the best going (a blister on the outside of the airframe) and the canopy rail at the rear.

Cheers,
Biff

 

[Peter Gunn]

Biff - Look at you all grown up and talking like a fighter pilot, one would think you've done something like this before...

Seriously though, that makes sense, it was sooo long ago I only remember him saying how easy it was to check while in cruise over where the bad guys live. For me looks wise the B/C really does it, but if I had my druthers and had to actually fight with the plane, hellz yeah, I think the D wins that one for the reasons you stated, I guess if I REALLY had my choice it'd be the P-51H.

 

[BiffF15]

I perhaps have a few tricks up my sleeves! Trying to look at it through the eyes of the author, I would guess he expected the threat to come from below (understandable once the Luftwaffe was fairly beat down). However, gentle S turns (or a wingman spread out a bit) allows for the same ability to clear ones low six and still retain the unparalleled visibility of the D. Once in a mature engagement or turning fight, the bubble offers much more ability to clear ones stern / pick up the visual on inbound bandits.

During the winter the contrails level over Germany is very low, so the bombers and fighters left many "hey look, planes this way" markers. If you are conning / marking, everybody knows (good and bad) where you are. You can play games with the cons by putting one guy up in them as bait, and several down below them waiting to kill whomever shows up (guys become fixated on what they can see). Or you can put a guy above the cons. Or you can make the cons stop. Oh the games we played...

Cheers,
Biff

 

[MIflyer]

Here are couple more items on the P-51. The engine mount drawing offers a bit different detail. Note that they built it up out of flat pieces since they were not able to get the required tubing fabricated in time to complete the prototype - and that necessity stuck with the airplane.

 

[henkypenky]

Hi Miflyer, thanks very much forthis great info; beautiful!

 

[MIflyer]

Here's a little more info. An article about NAA's production methods in the late 1930's and a couple more Mustang advertisements. I banged up my hand today trying to clean out the storage shed so I won't be on here for a while.

 

[Shortround6]

Heal fast and I hope it doesn't hurt to bad.

 

[drgondog]

Interestingly enough the tail fillet - or forward fin extension - on the B/C was not added for greater fin area but as a means of solving a problem with weakness in the horizontal stabilizer, presumably by tying into the aft fuselage more firmly. I suppose that the added fin area did not hurt anything, but of course the first D models built had no fin extension either, although they lacked the additional side area of the rear fuselage of the early models.

It seems that in postwar racing the bubble canopy models could not seem to beat the B/C racers. That additional fuselage fairing behind the cockpit must have been worth something.

The DFF primary purpose was to add Yaw stability through the slightly greater area - for both the P-51B/C and D/K. Both design drawings were completed in March 1944 (104-25001 and 109-25001) and kits were made up and included Reverse Rudder Boost kit. The Field installations began in June 1944 - about the same time P-51D-5-NA 44-13903 (#650) emerged with factory installed DFF.

The RAF experimented with both a DFF and a broader chord V.Stab between December, 1943 and Jan 1943 on Mustang X AL-963 - the DFF was a better solution but NAA experimented with fin cap & DFF before settling on DFF. The problem largely caused when applying/retarding throttle - requiring trim in each case as well as rudder input during the transition.

The P-51H design settled on stretching the aft fuselage by 13" before the Yaw stability was somewhat tamed.

Although it did Not provide any structural integrity, it also diminished the Yaw loads imposed on both the Horizontal and Vertical Stabilized via the prop vortex (up load on left H.Stab, down load on right H.Stab, and side load on V.Stab).

 

[N4521U]

Searching, searching....................... BAM................. end up back at WW2 ............. ah mazing!