DCS P-51D Block found out (and a bug)

So last night I tried to figure out which exact P-51D block was modeled in DCS.

I came to the conclusion that a P-51D-NA-30 must be modeled. Of these aircraft 800 units were built in total and they arrived too late in europe to see combat. They did however arrive in time to see combat in the pacific theatre.

This observation is based on a few highly indicative modifications in the cockpit. The landing gear lights were shifted to make room for the gyro gunsight control panel. The K-14 installation is not a field modded N-9 attachment and is instead the later K-14 attachment. It has the late style twistable throttle grip (definitely block 30-NA). Externally the DCS Pony has all the features expected of a block 30-NA as well. This includes metal elevators, rocket hardpoints, ass saving radar (AN/APS-13).

So since it is cleared up now that we have a post war (ETO) Mustang going against late 1944 configuration Luftwaffe planes, I dont want to hear anymore complaints! :smilewink:

Now while thumbing through manuals I found in the "Erection and Maintainance Instructions" (AN 01-60JE-2) a passage which contradicts the current DCS configuration. In DCS the IFF (SCR-695-A) is modeled. The cockpit panel can be seen in the following picture.

The problem being, that you cant install the IFF and the fuselage tank at the same time. The following pictures show where the fuselage tank is installed and how the configuration looks in DCS at the moment. (I mislabeled the fuel gauge as filler pipe in the picture.)

In the following picture it is very obvious why there can not be a simultanous installation of fuselage tank and IFF. Both would occupy the exact same space in the fuselage. You can hower see the SCR-552-A (radio) and in behind the battery are located exactly as in the DCS version.

Furthermore there are corrosponding text passages which make note of this limitation. It is described on two seperate occasions in the manual.

Now I checked if there were other options, but the only version which would allow a simultaneous installation of IFF and tank would be the following one. This is described as a korean era version and includes relocation of the battery into the engine compartment.

http://s212.photobucket.com/user/tourist-51/media/Picture1-51.png.html

It would be nice if someone of the ED staff could take a look into this. :thumbup:

Upon further investigation the corrosponding antenna for the IFF seems to not be modeled. It would be a small rod located on the underside of the outer right wing.

I was also wondering what these antennas do. Now I could find out that the dual antenna on the back was apparently used at Iwo Jima. The planes were equipped with an AN/ARA-8 homing adapter and MD-34 modulator keying unit nicknamed "Uncle Dog". The AN/ARA-8 panel is connected with the IFF panel in the DCS model.

Flying single-engine fighters on a round-trip of 1,200 nautical miles over a vast ocean with minimal onboard aids required a fancy bit of navigating. It was a task for which none of the Mustangs and few of the pilots were equipped to attempt on their own. The P-51 Ds had a magnetic compass and instrument panel clock; no radio compass or other nav aids. Voice communication was available by one VHF four-channel radio, and that was all. "You lose your radio or dynamotor and you have to time-and-distance 600 nautical miles to a spot in the ocean less than four miles in diameter," said Harry Crim. "Coming back if your radio worked you could get a steer for the last 100 miles from radar, if it was working. That's why you didn't want to be alone."

 

Fortunately, help was available. Six B-29 navigation planes, in three pairs, led about 100 Mustangs on each mission to a prearranged spot off the Japanese coast, and circled there while the 51s went inland. As the Mustangs began reaching the rendezvous point the first pair of B-29s waited until about half the fighters had arrived, then set course for Iwo. The other two pair of Superforts departed the coast at ten-minute intervals, allowing latecomers to latch on to one pair or the other. The last B-29 to depart continually transmitted on the "Uncle-Dog" frequency so any remaining straggler could home in.

 

Seventh Fighter Command frankly regarded Uncle-Dog as the greatest invention to come out of the war. It consisted of a pair of VHF antennae side by side on the 51 's aft fuselage, tuned one-quarter wavelength apart. Whichever antenna got a signal first would transmit to the pilot's earphones and suppress the other signal. The right-hand antenna gave a Morse Code letter U (dit-dit-dah) "Uncle from the phonetic alphabet. The left-hand antenna gave the letter D "Dog" (dah-dit-dit). The pilot then turned in the appropriate direction and refined the heading by watching his compass. When both signals were received simultaneously the pilot heard a steady hum, which meant he was on course for base or for the transmitting aircraft.

Is the lower centerline antenna maybe for the IFF (SCR-695-A)? It looks different from the AN-95 antenna in the manual, but I dont know what else it could be?! So maybe everything is correct and we have a special Iwo Jima stationed (PTO) version in DCS? These flew operations from April to August of 1945.

Edit: ETO stationed Mustangs did not seem to have employed the Detrola (BC-1206) radio and therefore had no overspan antenna wire.

Very interesting read on that topic: http://de.scribd.com/doc/39145899/WWII-Radar-Comm-Equipment

There is just no room for the IFF system (SCR-695-A). Behind the fuselage tank the oxygen bottles are stored and further behind there is the warning radar unit AN/APS-13 located. On top of the tank there is the VHF radio (SCR-552-A) as well as the battery located. No further space, except if the battery was moved to the engine compartment.

The antenna below the fuselage looks exactly as the VHF double antennas on the upper back fuselage.

Something at least is wrong! Either the cockpit panel or the 3D model.

Oh nooo!!! This is my favorite DCS bird and it has an error :( My question is, why would they replace a fuel tank with crappy 1940s IFF. I would have preferred a D-10 or 15 with more traditional N-9 sights.

Could someone from ED respond to this excellent research by Rel4y? Any plans of changing anything based on this?

Interesting stuff, thanks for posting, rel4y!

The bottom antenna is for AN/ARC-3 radio set.

Basically, we have an external model of mid '45 PTO Mustang, with an engine of early '44 ETO Mustang and mix of radio equipment from different periods.

The bottom antenna is for AN/ARC-3 radio set.

 

Basically, we have an external model of mid '45 PTO Mustang, with an engine of early '44 ETO Mustang and mix of radio equipment from different periods.

are u sure?

AN/ARC-3 radio set was after war (1948 ) instalation in F (T/F)-51D but bottom antenna was installed in P-51D during spring 45 with UncleDog...

Upper antennas are for AN/ARA-8 homing adapter (UncleDog).

Bottom antenna is for radio set SCR-552-A, it was moved from up because of AN/ARA-8 antennas.

No mix of radio equipment is in DCS P-51D, only battery behind cockpit should be replaced by SCR-695-A IFF and DCS P-51D layout fit exactly 7.AF`s P-51D on IwoJima, spring/summer 45 or short post war Ponies.

Engine in early 44 and mid '45 PTO Mustang is the same....

... all this technical talk. What's wrong with just pressing WASD to go up, left, down, and right? Heck, any nintendo or xbox can do it. Who needs joysticks?

:smartass:

are u sure?

 

AN/ARC-3 radio set was after war (1948 ) instalation in F (T/F)-51D but bottom antenna was installed in P-51D during spring 45 with UncleDog...

 

Upper antennas are for AN/ARA-8 homing adapter (UncleDog).

Bottom antenna is for radio set SCR-552-A, it was moved from up because of AN/ARA-8 antennas.

I did read posts about the ARC-3 on PTO Mustangs before, but I see some sources saying this was post war equipment indeed. I'm not an expert on radios so You might be right.

Engine in early 44 and mid '45 PTO Mustang is the same....

I was thinking about infamous higher manifold pressure clearance, discussed on these forums ad nauseam ;).

I wonder why it is infamous though. People have a wierd way of dividing stuff on worthy or not worthy of attention. It seems as some people are "too cool" to use something :P

Great research indeed mate :thumbup:.

So, IFF antenna is DCS P-51 vertical fin doesn't match to installed radios?

S!

DCS P-51D does not have IFF device only non-functional control box, so P-51 does not need IFF antenna.

DCS P-51D`s antennas match instaled radio equipment.

btw. IFF antenna was placed under right wing, behind wheel bay. It is barely visible on photos, because it was thin rod.

I wonder why it is infamous though. People have a wierd way of dividing stuff on worthy or not worthy of attention. It seems as some people are "too cool" to use something

I think the phenomenon is due to the faulty & incomplete USAAF manuals. Because the manuals (inaccurately) implied that the lowest of the WEP ratings for a given model was the maximum (or at least the standard), and since most printed secondary sources used the USAAF as primary reference, most people think that these lowest ratings were the highest or the norm.

So, to these folks, who've seen sources for decades listing e.g. 67" as the P-51D's WEP rating, a less well-known, later-in-the-war authorized rating like 72" looks like a revisionist addition, as if we simmers were pushing for a non-historical, non-standard rating to be included. Which, of course, is not the case. The problem lies in the USAAF manuals, riddled with errors and omissions, as they were.

Current P-51D was planned long before the Normandy map came to scene. So we have late war Pacific variant in the DCS now.

I'm very appreciated for such great research. We'll update our Mustang for War in Europe in near future.

I propose P-51D20 with 72'hg and G-Suit :3.:smilewink:

Upper antennas are for AN/ARA-8 homing adapter (UncleDog).

Bottom antenna is for radio set SCR-552-A, it was moved from up because of AN/ARA-8 antennas.

 

No mix of radio equipment is in DCS P-51D, only battery behind cockpit should be replaced by SCR-695-A IFF and DCS P-51D layout fit exactly 7.AF`s P-51D on IwoJima, spring/summer 45 or short post war Ponies.

Was the battery relocated to the engine compartment as was the case in korean era 51s? I couldnt find any useful sources nor pictures at the time I compiled the info into this thread. This must have been the only possibility all the radio equipment of the Iwo Jima 51s could be fitted into the plane while also retaining the fuselage tank.

PS: While were at it, here is a document (1990) publicized by NASA stating what I have done several times so far. Laminar flow on the Mustang is a persistent myth.

Russell G. Robinson of NACA Headquarters helped N.A.A. select the specific parameters for the most suitable laminar-flow airfoil shape for the XP-51 A, B, and D models. Operational environments prevented laminar flow. The laminar flow airfoil's primary advantage proved to be the increase in its critical Mach number, thus postponing drag rise, severe buffeting, large trim changes, etc., due to shock stall.

crgis.ndc.nasa.gov/crgis/images/6/62/NACA_Contributions_to_the_N.A.A._P-51_Airplane_Reeder.pdf

I think the phenomenon is due to the faulty & incomplete USAAF manuals. Because the manuals (inaccurately) implied that the lowest of the WEP ratings for a given model was the maximum (or at least the standard), and since most printed secondary sources used the USAAF as primary reference, most people think that these lowest ratings were the highest or the norm.

U are so wrong.

Manuals waren`t (and aren`t) issued inaccurately.

If we talking about allowed manifold presurre, Mustangs were built in some standard, let say "global standard or factory standard" like other planes and it was 67" inHg in case of manifold pressure and with some equipment. And this standard was covered by "factory" manuals, like Pilot operating manual, Maintenance instruction and etc.

But

before planes reached frontline unit, they had undewent several modifications which were required for particular battlefield, IFF, radio, specific navigation devices and others or engine upgrade.

These modifications were covered by different kind of T.O., bulletins ... and not by factory manuals.

75" inHg upgrade were covered by several documends and they weren`t mandatory for all Mustangs but this particular modification was released only for ETO, 8th AF exactly, and the other Mustang users did not do it.

During long Mustang service, 75" inHg was used for short time and only one user but yes the most know and famous.

So, if DCS is 8th AF simulation, 75(72)inHg will be necessary but it is not now.

Was the battery relocated to the engine compartment as was the case in korean era 51s?

yes, exactly

battery was placed between oil tank and intercooler

Well thats the picture I posted before, but it apparently is a post WWII doc. When I was looking for confirmation of my guess, I couldnt find any technical order describing the changes necessary. :/

only presumptive evidence, photos where air intake for battery vent on L/H nose side or inertia switch behind armor plate is visible.

only presumptive evidence, photos where air intake for battery vent on L/H nose side or inertia switch behind armor plate is visible.

Makes sense.

Here is a guy claiming the battery relocation was a modification done to Uncle Dog installed, as well as block 30NA models. Cant confirm the latter though.

When you delve into the details (the intricate and not so intricate differences between say a P-51D-10-NA, to a P-51D-15-NA, P-51D-20-NA, or P-51D-25-NA, etc.), it isn't of the exact D-model types that you would have seen in Europe during WWII, although a few P-51D-30-NA's did make it to the Pacific very, very late in the war. Just one such detail that sets apart a P-51D-30-NA, from earlier makes, is that the battery was moved to the engine-bay, from where it had been positioned behind the pilot's armor plate on previous models (those out-fitted with the 'uncle-dog'/VLR antenna setup, also had the battery moved in such a way) - so the Mustangs that you would have seen in Europe during WWII, and most of the examples you would have ever seen in the Pacific/CBI, had the battery behind the pilot (the easiest way to notice if the battery was re-positioned, is by a little battery vent-scoop that is mounted on the port-side of the nose, on the wing-fuselage elbow fairing).

IMHO i do not think that Uncle Dog was a reason for battery movement, it was so small two boxes with control box and antennas.

SCR-695-A is big as battery is or nearly that. I think it was reason for battery movement.

Mustangs, block -25, on one picture from factory line look like equiped with air vent for battery, but picture is not perfect... Because of it (and IPC from November 45) I think that this local modification, battery movement, become "factory standard".

btw. 75inHg remained only temporally modification for while and one location

for info, Iwo Mustangs were -20 and -25 and air vents for battery were at least two different shape, "early" probably designed by local modification centre and "standard" designed by NAA or adopted by NAA perhaps.

IMHO i do not think that Uncle Dog was a reason for battery movement, it was so small two boxes with control box and antennas.

SCR-695-A is big as battery is or nearly that. I think it was reason for battery movement.

Neither me nor the quoted text said Uncle Dog was the reason for battery movement. As shown in the opening post, simultaneous use of IFF (SCR-695-A) and fuselage tank made the battery relocation necessary.

I have read, that some production line 25NA had the battery relocated to the engine compartment. Some people say with block 30NA it became standard. As I said, I cant really confirm this.

Excellent research + rep for you.

It is unfortunate that the P-51 modelled isn't in the 1944 period but as it was developed long before there was even going to be a 1944 map and associated aircraft set - it's disrespectful for people to slam them about it.

Raccoon above said They will update a '44 model which is fantastic news for accuracy in the upcoming theatre.

Once the pacific things get fleshed out a bit more it will be nice to play with the current mustang around the pacific against (hopefully) the AM6 that LN might be developing (while it outclasses the AM6 it will still be nice to have a historical opponent).