Lockheed XP-38N Lightning for FS2002
by David C. Copley

Version 3.2
14 Jun  2002

 

Contents

Installation

Project XP-38N

Facts about the Lockheed P-38

Fiction about the XP-38N

The visual model

Flight dynamics

Flying Hints

Damage Profile

Acknowledgments

References

Usage / Distribution / Permissions etc.

About the Designer

xp-38n3mtsocean-bw.jpg (21183 bytes)
The only known photo of the XP-38N in flight.

xp-38n3b.jpg (12130 bytes)
The first photo of the XP-38N just after roll-out.

(just pretend!)



Installation

1. If you have installed a previous version of XP-38N in FS2002, remove it by removing its folder from the FS2002's Aircraft folder before installing the new version.

2. Unzip the file XP-38N.zip in FS2002's 'Aircraft' folder. A folder named XP-38N and several sub-folders will be created. 

3. The panel uses a few custom gauges. Copy the *.gau files from the XP-38N\gauges folder to FS2002's gauges folder.

Notes:

This model is intended for FS2002 only.  While it shares much in common with its FS2000 and CFS2 predecessors please do not attempt to run it in anything but FS2002.

After installation, there will be two visual models contained within the same XP-38N folder.   Within in the simulator, two separate varations of XP-38N will be available: metal and black. 

Be sure to visit www.kazoku.org/xp-38n for the latest updates, more other P-38 models, and lot's of P-38 pictures!

Project XP-38N

Project XP-38N is my on-going effort to model what might have been the next version of the P-38 had the war not ended.  My first version was for FS98 and later versions subsequently supported CFS1 and FS2000 and now CFS2 and FS2002.  I also have made a P-38L-5, P-38M, P38J-15, P-38J-15 Droop Snoot, and a P-38J-20/F-5E-2 Photo Lightning.   Eventually I hope to make all P-38 variants, with XP-38N being my flagship model.  

Facts about the Lockheed P-38

The Lockheed P-38 Lightning was one of the most prominent fighters throughout WWII in both theaters of operation. P-38s scored the first kills in the Pacific Theater as they served in the arctic cold of Aleutian Islands. In Europe, they often provided high-altitude long range escorts for bombers.

The P-38 was originally developed in response to the US Army Air Corps' need for a high altitude 'interceptor' in the late 1930s. The Air Corps' requirements specified a craft that could reach an altitude of 20,000 ft in six minutes, attain a top speed of 360 mph and fly at full throttle for one hour. In addition, it would carry more armament that any previous fighter.

Lockheed's legendary aeronautical engineer, Kelly Johnson, drew on his past experience with twin-tail craft such as the Electra and proposed a twin-engine, twin-boom arrangement with turbo-supercharged engines. (Kelly Johnson went on to design the F-104, the U-2 and the SR-71.)

The XP-38 was first flown in January 1939. After logging just 11 flight-test hours, it embarked on a record-breaking cross-country flight that proved the capabilities of the design, but also lead its demise when it plowed into a golf course just before landing.

The only fighter-craft to remain in production throughout the war, the P-38 proved to be a very versatile platform for a wide range of operations including long-range escort, photo reconnaissance, fighter/interceptor, ground attack, and even formation bombing. It evolved through several variations, each iteration more successful than the last.

Perhaps its strongest asset was its concentrated fire power. Being a twin engine aircraft allowed it to have four guns and one cannon mounted in the nose. This clustered arrangement meant that the guns did not have to be sighted to converge at some optimum target range. In the hands of skilled pilot, the Lightning was a formidable fighter. No wonder America's top two fighter aces scored their victories in P-38s.

However, it was not without its faults. Early into the European war it gained a reputation for poor high altitude performance. Even though this was eventually traced to the use of lower-grade British fuels, the reputation remained. The two liquid-cooled Allison engines required a lot of attention, and there was trouble with the turbo superchargers as well. The P-38 was the first aircraft to seriously encounter a potentially fatal phenomenon: compressibility. During a high-speed dive the wings would lose lift, resulting in loss of control. The enemy soon began exploiting this weakness to elude the P-38s. The problem was finally solved when, late in the J series production, dive recovery flaps were added which gave pilots the freedom to enter into high speed dives with confidence. Early Lightnings also had poor roll rate and required a lot of muscle to turn.  When the dive recovery flaps were added during the J-25 production block, hydraulically boosted ailerons were also added.  This welcome addition gave pilots "power steering," greatly increasing the roll rate.

As the need for night fighters increased, Lockheed produced the two-seater M series. The addition of a radar operator relieved the pilot from radar duties and allowed him to concentrate on the mission objectives.

Nearly 10,000 P-38s were built, the bulk of which where J and L series. After the end of the war, the Army Air Force surplused them for $1,200 a piece. Of course you had to arrange for delivery, which was no trivial task since as many of them were in the south Pacific. Today, only a handful remain. Only a few are in flying condition.

Fiction about the XP-38N

[The following is fiction, but is based on some fact.]

Just after the first test flight of the P-38M Night Lightning, work began on the next series to be labeled 'N.' Lessons learned from the successes and failures of the L series and some of the technology used in the M upgrades were incorporated into the functional specifications for the N series. In addition, some ideas and concepts tried in the XP-49 and XP-58 (both based on the P-38) were added to the N-series plans.

From the onset, Lockheed hoped the N-series would be the next generation, or third generation, of Lightnings.  (The original up through the G were the first generation, and the J and L were the second generation.)  The USAAF was highly critical of the N-series plans, for they felt Lockheed's attention should be focused squarely on jet fighters, particularly the P-80 Shooting Star which was just on the verge of production.  Yet, a few visionaries realized that jet fighters, while vastly superior in speed, were also severely limited in range.  It was thought that a faster P-38 equipped with modern advances in space engineering, material sciences and avionics could still fill a needed role in the air force. 

Lockheed engineers had tweaked the Allison V-1710-111/113 F series and had managed to get its wartime emergency power rating up to 1850 hp without much added weight or change in space requirements, other than a few enlargements to the cooling system. A few P-38L's had been fitted with these modified engines but there was considerable skepticism whether they possessed the durability and reliability needed for combat. Thus Allison and Lockheed committed to formally develop an updated engine incorporating the modifications. The timing worked out such that this updated engine was specified in the XP-38N experimental program.

With a firm strategy in mind -- to re-vamp the P-38 into a next generation long-range, high altitude, multi-purpose attack/defense platform -- designers first addressed "legacy" features that were thought useless.  For instance, after too many pilots were killed striking the horizontal stabilizer's external mass balances as they bailed out of doomed P-38s, orders finally were issued to remove them from the design. As Kelly Johnson had predicted years earlier, they affected the flight dynamics very little. A replacement design was never needed. (During the development of the YP-38, these balances were added in an attempt to fix a severe buffeting problem. The problem was solved when fillets were added where the main wing joins the fuselage but the balances remained on all subsequent variations.)

When VE day came, the US turned its full attention to the Pacific, and the need for longer and higher altitude escort and photo-reconnaissance increased.  Lockheed returned to a concept explored in the short-lived A-series experimental program, a pressurized cockpit. Anticipating a large-scale invasion of Japan, the military asked designers to delete the retractable boarding ladder and move the components in the rear of the fuselage to make room for an additional fuel tank. This would free the wing pylons from fuel duty and allow them to carry ordnance. When the rear components were moved, new innovations in space engineering along with smaller components allowed the cockpit to be enlarged, which would give pilots a little more room to stretch their arms and legs on long duration flights. Also, it was thought that the extra room would facilitate conversion to a two-man configuration should the need arise. Even an ejection seat was specified for the new cockpit.

In all, the following changes were proposed for the N-series:

The first N series prototype, dubbed 'XP-38N', and equipped with a pressurized cockpit, was scheduled to roll out the second week of August '45.  But two significant events, both occurring on Aug 6th, postponed the roll-out and flight test program: 1) The first atomic bomb, and 2) the untimely death of P-38 Ace R.I. Bong.  Maj. Bong was working at Lockheed as a test pilot at the time and was scheduled to take part in XP-38N's roll-out ceremonies.  Out of respect for the Ace, the program was postponed until after his burial.  By the time XP-38N rolled out, Japan had surrendered and the war was over.  

When XP-38N finally made its first appearance, onlookers observed that its airframe was pretty much the same as the J and L series. However, the prototype's paint scheme stunned USAAF dignitaries: matte black with large black and white, D-Day style invasion stripes, and twin shark mouths.

Legend has it that one set of orders came through that said XP-38N was to be painted black with minimal markings, similar to its immediate predecessor (the M series, Night Lightning). Another set of orders (from a different chain of command) specified D-Day style high-visibility markings to emulate what might be used in a large-scale invasion (though to be the N-series' primary purpose). Yet no specifics were given. The end result was a practical joke by the painters, who were never told which order to follow. They simply followed both, resulting in an ironically contradictory livery. The shark mouths (which were a common feature on large cowl aircraft in the field) were added as 'icing on the cake.' 

The airplane was ordered stripped of its unique paint scheme and returned to an all-metal look.  Paying homage to the original XP-38, detailers painted the old-style red, white, and blue stripes on the tail.

Due the end of the war, the XP-38N program was in jeopardy and work tapered off dramatically.  As end-of-war celebrations diverted most people away, the XP-38N was performing standard engine run-up and taxi tests.  Finally, on a warm morning in late Aug 1945, the XP-38N took to the skies of Southern California for a brief 30 minute flight.   The very next day the XP-38N program was officially cancelled and the plane never flew again.

The visual model

For any FS model, there can be up to four aspects of the visual model: 1) external geometry, 2) textures (paint), 3) 2D panel and 4) virtual cockpit (some even have a 3D working panel).   My design is intentionally a balance between computer performance, modeling time (that is, the time I can dedicate to this hobby), aesthetics, detail, etc.

External Geometry

FSDS 1.6 was used to build the model.  I also made extensive use of scanned 3-view plans from various P-38 books (see References).  There are some visual flaws that I hope to rectify in later versions.  Good frame rates (even on older systems) became my highest priority, and I achieved my goal of having the model around 3000 polygons.

In version 3.2 I've made a few minor enhancements to the cockpit and textures.

AA 1.3 was used to animate the parts. Animation features include:

*There was no control of the nose wheel on any of the the real P-38s.   Steering was accomplished with differential braking and differential thrust.   The nose wheel was a caster, and simply moved like a shopping cart's front wheels.  But XP-38N has rudder-control steering!

Textures

Two textures are included with this release.

  1. Black w/ D-day markings 
  2. Metal, with Copley family coat of arms and red-white-and-blue tails

The basic textures were derived from scanned images obtained from several scale-modeling books on the P-38 (see References below).  I then attempted to make them appear metallic with Paintshop Pro.  I am not a graphic artist, but I did the best I could.  For me, painting the model is the most difficult and tedious part of the entire project. 

The textures are 512x512 32-bit bitmaps. 

2D Panel

My objective for the panel design was what one flight-sim designer has dubbed "functionally realistic." It is based on photos of actual P-38 panels, with emphasis on the P-38L.  I have re-arranged a few items, particularly the fuel gauges -- moving them to the right, next to the other engine gauges.  There are dual RPM gauges as on the early P-38s, whereas the P-38L had a dual-need RPM gauge. I have added a few things here and there too for the sake of my flying preferences. I included one modern instrument on the main panel for ADF and VOR2, replacing the P-38L's standby magnetic compass found in the upper left corner. The dive recovery flaps are modeled as spoilers, and as such are controlled by pressing the spoiler key ('/').  I used my imagination for the gauge design.  The numbered switches can be used to access the custom throttle quadrant, GPS and the starter panel.  A panel with autopilot and NAV radios is also available, and is accessed through a standard FS2002 icon.  Note that on the throttle quadrant, the right mouse button can be used to adjust each engine/propeller/mix separately.  

The panel bitmap image is half-height and does not include front window frames.  This was done for two reasons: 1) I prefer good visibility over such levels of realism and 2) I have found that a full size bitmap reduces simulation performance and I wanted to strike a balance between function and form.

For your information, I prefer VFR flight-simming. Someday maybe I'll figure out how to use all those navigational instruments well enough to fly above a thick cloud layer and end up at the right place. But for now, I take to the virtual skies to see things (or shoot at them, in CFS2). Many aspects of this model package reflect my bias for VFR.

Prior versions of the panel had several dummy gauges.  The new panel only has one: the vacuum gauge, an image based on photos of actual P-38 panels. I never need it for my flying and I didn't want any CPU cycles going to waste.

Virtual Cockpit

I first introduced a simple static Virtual Cockpit in version 3.0.  Since then, I have steadily improved the VC by adding better textures, dynamic gauges, animated wheel, etc.   While I am slowly refining it but it is doubtful I will ever produce a masterpiece.  For a great P-38 virtual cockpit, I recommend the P-38J-25-LO by Blue Arrow/Flight One.

Sounds

The sounds are a mixture of originals by me and MS stock sounds modified by me.  The spectral foundations for most of engine sounds were synthesized by me using an experimental technique called physical modeling.  Then I mixed in some other self-recorded, heavily-modified odds and ends (including my lawnmower, my electric shaver, my home heater/air conditioner blower, and a turbocharger from a diesel engine). The results are quite different from any engine sounds heard in other flight simulator add-ons, and reflect my imagination of what a modified Allison might have sounded like.  Also, I combined propeller sounds with the engine sounds at medium to high RPM, for the sake of download file size economy.  Note that at high power (high RPM & high manifold pressure) you can hear the turbos! 

Flight dynamics

I readily admit that I am not a pilot. Ironically, I actually hate real-life flying and avoid it whenever possible. But I can spend hours and hours flying my P-38!!!  (I even flew it around the virtual world!)

Earlier versions of XP-38N had AIRs file based on FS98 AIR files.  I spent hundreds of hours developing those AIR files and I didn't want to give them up.  For version 3.0,  I successfully transferred many of the old parameters to a CFS2-based AIR file and then made adjustments until it flew pretty much the way I wanted it.  For this version, I used FSEdit to transfer the primary flight model parameters to the aircraft.cfg file, as per FS2002's new approach. 

The flight model for version 3.2 is the same as version 3.1.  With version 3.1, I   overcame one of the major limitations in previous versions: propeller torque effects.  Not until CFS2 could counter-rotating propellers (and the resultant zero net torque) be modeled properly.  With CFS2, the method was simple but had several undesirable side effects -- propeller animation and gauge problems -- so I was unable to implement it in version 3.0 for CFS2.  Recently, with some help from online acquaintences, I overcame these problems. 

Aside from the modeling of counter-rotating propellers, this flight model is basically the same as the CFS2 version of 3.0.  A major part of updating the dynamics from version 2.0 to 3.0 was accomplished by modeling the P-38L.  For that, I sought some help.

First, I obtained P-38 videos and printed references that I studied carefully (and continue to study).  Second, I sought help from those who actually flew the plane.  I have had the privilege of corresponding with a former P-38 pilot, Lt. Col. (ret) William C. Sharpsteen II, who flew with the 339th FS/ 347th FG in the South Pacific.  Mr. Sharpsteen has taught me much about the handling of the P-38, in the air and on the ground, and about the differences between the earlier G model, which he spent quite a bit of time in, and the late J-25/L, which he also flew. 

The flight model was designed and tested mostly in CFS2, with the flight model difficulty level set to "Hard," or 100%.  It has also been tested in FS2002 with full realism applied.  During certain maneuvers above 450 mph the plane will buffet a bit.  This is intentional. While the actual plane may not have buffeted exactly like this, I am trying to simulate the fact that it did have a tendency to buffet at high speeds as indicated in the actual flight manual.  As stated in the actual P-38 pilots manual, use the dive recovery flaps to stop the buffeting. You will also note that it rolls very well at high speeds and, at most speeds, it is very difficult to stall, which was apparently true of the actual airplane.

I do not claim this to be the best or the most accurate flight dynamics model for the P-38, as AIR file/flight dynamics modeling is still somewhat of an art.  However, I do believe I have captured the essence of the late-model P-38 and what might have been the next stage in its evolution.

Flying Hints

Best taxi speed is below 50 mph. Use differential braking (F11 and F12), differential thrust or the nosewheel for steering. For best results, use a combination.  For tight turns, slow down to just a few mph.

Rotation occurs about just above 100 mph with flaps at first notch, 110 mph with no flaps (full fuel).  From a complete stop, the plane should take only 1,000 ft to be airborne (just like the real P-38).  Retract gear as soon as you can. If you take off from near sea level, you’ll find it really wants to climb! It likes to cruise between 270 and 300 mph IAS, depending on altitude. All those horses really like to climb so use trim liberally for level flight. Also, all those horses like to drink, so be sure to cut back on the fuel mixture if you want to fly for any great distances.  Max speed is about 440-450 mph, though you may be probably push it a past that in a dive before buffeting begins. Max distance is about 1,4000 miles.  For longer flights, you can edit the aircraft.cfg and 'enable' external tanks -- though FS2002 won't show them.

Use the dive recovery flaps to mitigate overspeed, especially on dives. Roll rate and recovery is fairly quick. Sharp turning at high speed may result in loss of control. Be sure to land gently, at no more than 130 mph. On approach with throttle back, once you extend full flaps and lower landing gear you will find yourself piloting a gliding rock. You may need some throttle to keep on your glide slope. Don’t use the dive flaps during final approach unless you absolutely need to slow down, and even then I would not recommend deploying them until you’re very close to the runway. 

Since there isn't any combat in FS2002, the need for speed bursts isn't as crucial.   But, if you're racing or just out for a joy ride and want maximum power, use the WEP switch to engage WAR EMERGENCY POWER.  WEP can only be engaged when at full throttle (COMBAT POWER).  Also, if you run at WEP for too long (a few minutes) you risk damaging the engines.

Damage Profile

The included DP is from the CFS2 version of XP-38N.  FS2002 only uses certain sections of the DP.

Acknowledgments

Gauges

The engine, propeller and mixture control is a modified version of HGHB's HGHB_STCK_TWIN_PROP.GAU. It's appearance was modified by me with permission from Harald Geier of HGHB Virtual Instruments. Please note the accompanying HGHB documentation.

WEP gauge programming by Mike Wagner (MoparMike)

Starter switches by Chuck Dome

Gyro Compass (Military RMI) - Richard Melville (This is the only 'modern gauge' on the main panel. I placed it where the standby magnetic compass would normally be and included it for limited IFR flying)

P-51 ball gauge: Jim Goldman

vertical speed gauge: 'DocBlake'

Left and Right fuel gauges: Graham "DOTCOM" Waterfield, FSD

Switches by Dai Griffiths, DragonFlight Designs.

the remaining gauges are either stock or modified from stock gauges

Resources / Influences / Other

714th Research Center - for their methods and AirEd.ini file.  While I did not employ their "Assembly Line" process, I admire their methodical and scientific approach and have learned much from their work. 

CFS2 Online and Combat Flight Center, AVSIM, FlightSim, and all the great PC-aviators that contribute to the forums.

Special thanks to my family for putting up with my P-38 obsession!

References

Books

Web pages

Videos

Usage / Distribution / Permissions etc.

This model is released as FREEWARE.  If Freeware can be copyrighted, then I claim Copyright © 1998-2002 David C. Copley. This package, including each and every file, may NOT be included in a commercial package.

I grant permission to repaint the visual model and/or modify the flight dynamics and/or modify the sounds, so long as such derivative works are released only as FREEWARE and include proper credits for all respective authors. You are NOT authorized to modify or distribute the gauge file xp-38n_EngProp.gau.

Version History

14 June 2002 - XP-38N ver. 3.2

26 Jan 2002 - XP-38N ver. 3.1

14 Jul 2001 - XP-38N ver. 3 (CFS2 and FS2000 versions)

21 April 2001 - P-38L: ver. 1.1.0 (XP-38N ver. 3 Phase 1) for CFS2

28 Mar 2001 - P-38L 1.0.0 (XP-38N ver. 3 Phase 1) for CFS2

9 Oct 2000 - metal paint scheme for XP-38N ver. 2 for FS2000

22 Apr 2000 - XP-38N ver. 2 for FS2000

17 Jan 2000 - XP-38N ver. 1.1 for FS98/CFS

20 July 1999 - XP-38N ver. 1.0 for FS98

Sep 1998 - began project XP-38N

About the Designer

By day I am an acoustical engineer for a major industrial company.  By night (when I'm not spending time with my family or engaged in other real-life activities) I am a P-38 nut.  I am also a musician, so my 'free' time is split between flying/making P-38s and making music.

You may contact me at db@kazoku.org, or visit my web site www.kazoku.org/xp-38n.