History and Details of the P-51D-5-NA (A Flight Sim Project)

[Bomber_12th]

I want to welcome everyone to another "history lesson" from your resident Mustang aficionado (putting it lightly). : ) I also want to spend some time introducing you to one of Warbirdsim’s up-coming products for FSX, the P-51D-5-NA. I hope you enjoy!


The Birth of the P-51D

Not all too unlike the original request for P-51 development, or the integration of the Rolls-Royce Merlin engine into the airframe, or even the genesis of the name itself -Mustang - the initial concept behind what would become the P-51D, the most known and recognized of the series of Mustang fighters, can be traced directly to Britain.

By early 1943, the British had figured out how to create a bubble or “teardrop” canopy, providing a clear 360-degree view all around, and began installing them to the latest mark Spitfires and Typhoons. The USAAF sent Col. Mark Bradley to England in January of ’43, to “learn the workings of this new canopy and find a way to get them onto U.S. fighters.” Upon return, Bradley immediately set forth to incorporate this new style of canopy design into U.S. fighter production. The first USAAF fighter so tested was the Republic P-47.

Not wasting any time, P-51B-1, 43-12102 was selected off the North American Aviation assembly line, to be modified as a test aircraft for the new bubble canopy, and house-designated the NA-109. The new canopy provided almost complete unobstructed vision, with virtually no distortion from the free-blown glazing. This new canopy was mounted to rollers, connected via chain and pulley to a manual hand-crank assembly on the starboard side of the cockpit. In order to accommodate this new canopy, the rear fuselage had to be cut down. This modified P-51B took flight for the first time on November 17, 1943, under the control of famed NAA test pilot Bob Chilton.

The success of 43-12102 led NAA to modify P-51B-10-NA 43-106539 and 43-106540, under a new house-designation, NA-106. These aircraft would effectively become the first of the true line of P-51D’s, officially titled XP-51D, and later P-51D-NA. Beyond the canopy modifications, the aircraft’s wings were also modified, with the addition of six .50-in machine guns (rather than four, as on previous Mustangs). The new mounting setup for the machine guns also corrected the gun-jamming issues that plagued the P-51B’s and C’s.

The landing gear operation was also re-designed, and this led to an increase in the wing root chord. The angle of the main landing gear struts, the main landing gear doors, and the entire main gear wells were completely changed. Improvements were also made to the effectiveness and strength of the ailerons. The landing light was moved from the wing leading edge to inside the landing gear well.

The very first production P-51D’s, officially titled P-51D-5-NA’s, began to enter service in Europe in late May and early June, 1944, just in time for the D-Day invasion, and the events that followed. Some of the most all-time recognizable P-51D’s – “LouIV,” “Cripes A’ Mighty 3rd,” “Frenesi,” “Hurry Home Honey,” “Donald Duck,” “Flying Dutchman,” “Happy Jack’s Go Buggy,” and the 52nd FG “Marie” – were P-51D-5-NA’s.

By mid-late P-51D-5-NA production, a report that the tails of P-51B’s, C’s, and D’s were failing structurally due to violent snap-rolls, had to be addressed. North American engineered a fillet for the dorsal fin, which tapered up into the vertical stabilizer from the point of the production-break between the fuselage and tail assemblies. This fillet both added more structural strength, and also cut down on the violent effects of snap-rolling the aircraft. This fillet was first installed on the last few production P-51D-5-NA’s, and into P-51D-10-NA production. Through a technical order that was issued, kits were also sent to all P-51D-5-NA’s and early Mustangs already operating in the field. These fillets were of a slightly different construction-design than those fitted in production of later P-51D’s.

Now, to dig into some of the finer details of what made the P-51D-5-NA unique to any other D-model, I have compiled together a list of just some of the unique details that set it apart, and I hope to illustrate these points through screenshots of Warbirdsim’s up-coming P-51D-5-NA product. This is by far the most focused P-51D-5-NA ever designed for any flight simulator platform, and I hope to continue to provide more screenshots and information on the product, through updates posted to this thread, up until the point that the product is released in the coming days. All screenshots feature “work-in-progress”, thus-far.

[Bomber_12th]

First of all, I’d like to provide a detailed look at the exterior of the P-51D-5-NA.

- The most obvious, defining feature of the P-51D-5-NA, is the lack of a dorsal fin fillet. The flight characteristics, as a result, were different when it came to yaw-stability, or the lack there of. This handling difference has been incorporated into the new flight dynamics for the Warbirdsim P-51D-5-NA.

- There was no oil radiator drain added until P-51D-10-NA production, so along the bottom of the lower cowling panel, there is no oil drain access door. There was also yet to be a fuel strainer access door added to the lower cowling panel, until late D-model production.

- The gun camera port was circular in form on the P-51D-5-NA, but on the P-51D-10-NA and later models, with the gun camera type changed, the gun camera port would became rectangular in form.

- A static ground wire below the tail was not yet added. This would become standardized on P-51D-15-NA production.

- On early P-51D's, the oil access door atop the nose cowling, was of the same size and design as that of the aftercoolant access door. The oil access door would not be enlarged until P-51D-20-NA production, when a dip stick was provided, requiring additional room to be accessed.

- On early P-51D's, the elevators were still covered in fabric, just as the rudder. By later P-51D production, the elevators were "metalized".

- Unique to the P-51D-5-NA, a white, upward-facing recognition light was fixed to the spine of the aircraft, just behind the radio antenna.

- The design of the canopy plexiglas, as fitted to P-51D-5-NA's, was also entirely unique to just the D-5-NA production run, with the tallest portion of the canopy actually positioned behind the pilot's head. The canopy plexiglas would be re-designed for P-51D-10-NA production, with the tallest portion of the glass positioned well-forward, and would become the standard canopy design.

- Until P-51D-10-NA production, there was also not yet an external push-button release for opening the canopy externally, as would be installed near to the emergency canopy release handle.

Both “Glengary Guy” and “The Comet” are un-finished at this time, but very near completion. 7-historic examples of the P-51D-5-NA will be covered, and matched to their unique and individual configurations.

20th FG "Glengary Guy"

[Bomber_12th]

339th FG "The Comet"

[Bomber_12th]

On to the interior details.

- The instrument panel, as clearly illustrated, was pure P-51B/C in design and layout. On P-51D-10-NA and later production, the instrument panel layout was re-designed, and the instruments were front mounted instead of rear mounted.

- The main electrical panel design within the P-51D-5-NA featured a 4th recognition light switch, for the white recognition light on the spine of the aircraft. This panel would be re-designed on P-51D-10-NA production and onwards, with the deletion of the upward facing white recognition light, and the layout of switches changed.

- The D-5-NA’s featured an earlier mixture control, like the P-51B’s and C’s, with positions at "Idle Cutoff," "Auto Lean," and "Auto Rich." This would be replaced with a single position mixture control and plate with positions at "Idle Cutoff," "Run," and "Emergency Full Rich" on P-51D-10-NA's and later models.

- On P-51D-10-NA's, the oxygen warning lamp, as installed on the instrument panel in the P-51D-5-NA, was made inoperative, and would later be completely removed. The oil gage service line connection, and the vacuum system adjustment knob, on the instrument panel, would also be removed with the instrument panel re-design on P-51D-10-NA production, with the vacuum system adjustment knob moving behind the instrument panel.

- An N-9 reflector gun sight was installed on P-51D-5-NA's, and would remain the standard production-installed sight until mid P-51D-20-NA production. A backup ring and bead gun sight was also provided, which would remain until mid P-51D-15-NA production.

- The throttle lever installed on all P-51D's which were manufactured with the N-9 gun sight, was the standard sphere-grip type. The throttle lever would change to a twist-handle, "bicycle grip" throttle lever with the introduction of the K-14 gun sight during P-51D-20-NA production.

- Early D-models, including the D-5-NA, only featured a carburetor air control lever at the back of the trim pedestal. Later aircraft would have a carburetor hot air control lever added next to the carb air control lever.

- On early D-models, the armor plate was positioned lower than that on later examples. On P-51D-20-NA production, and onwards, the armor plate was raised 2.25 inches. Until this time, the canopy was allowed to travel backwards, beyond the position of the armor plate. Due to the raised-position of the armor plate on P-51D-20-NA's and later models, the canopy was limited in travel.

- A manual primer pump was installed on the P-51D-5-NA, and would remain until P-51D-15-NA production, when an electrical primer was added.

- On P-51D-5-NA's, the seat installed was that of an early version of the Warren McArthur tubular-frame seat, as was commonly installed on P-51B's and C's before.

- The P-51D-5-NA had an early-design spare bulbs locker, directly below the oxygen regulator, which was the same as was incorporated into the P-51A's, B's, and C's before it. By P-51D-20-NA production, this spare bulbs locker was removed, and a spare bulbs shelf was added to the inside of the instrument panel shroud.














Through the illustrations from the original manuals, as well as period photos, here is a further demonstration of how things changed between the P-51D-5-NA and later P-51D's (they weren't all created equally!). : )

The P-51D-5-NA instrument panel (actually not fully correct in this illustration), and the later re-designed panel as seen on all other P-51D's.





The P-51D-5-NA main electrical panel layout, and the layout of the main electrical panel on all other P-51D's.





And some illustrations, demonstrating the oil gage servicing outlet, and the vacuum system adjustment knob, as only seen within the cockpit on the P-51D-5-NA.

[Bomber_12th]

As far as I know, this is the first time a fully-modeled N-9 reflector gun sight has ever been created for a Microsoft-based flight simulator platform.

Through some mad material and texture experiments, I was able to reproduce the reticle in collimated and true-"lit" form. The reticle itself is actually truly "translucent", and really glows, appearing as if projected by a light source, just as in real life.

Here are some screenshots showing the reticle under different conditions.

[Sundog]

That looks great.

As a side note, wasn't the Miles M.20 the first fighter, granted it was a non production aircraft, with a bubble canopy? I don't know if it was distortion free or not.

Also, are there still plans to bring a native FSX version of your P-51B/C to FSX? Is this the stepping stone to that?

They look great, but that's being pathetically redundant on my part, as we already know full well the quality of your work. I was just flying one of your P-51's the other day, but there are hundreds if not thousands of those stories to be told in this forum.
I love reading your Mustang history lessons as well. Don't stop.