Review: Flight Replicas L-4 (FSX)

fishingrodWho doesn’t know what a Piper Cub is? Come on, hands up? No one? Good. Now who can honestly say what an “L4” is? To be honest, I had to raise my hand at this point, but when I saw the pictures of Flight Replica’s L-4 for FSX I really thought “Piper Cub”. Of course, those who thought thus are technically right. The L4 is the military version of the Piper J3 Piper cub. You can buy this plane on simMarket of course.
With some five and a half thousand variants built during WWII, this “Warbird” rightly deserves a place in the world of flight simulation. With that in mind, here is a review of the FSX model created by Flight Replicas who also brought us planes such as the ME262 and the ME109.


I have had the opportunity to discuss some of my critiques with the developer and owner/manager of Flight Replicas, Mr. Michael Flahault. He is a real life GA pilot and he does have direct contact with L-4 / Piper Cub owners. This review will include the changes as clearly marked additional paragraphs so that you, dear reader, can see where I stand corrected.

Basically, there is nothing on this model that needs changing although there are a few things that could do with some consideration.


The potted version (skip to summary)

The full version (read on)










Various screenshots – for those with time

The test system

About the author


reviewl4_1During the early days of World War 2, the US armed forces needed a light liaison and air observation aircraft to act as “gopher”. All armies need aerial intelligence to conduct their operations and using flying machines had proven invaluable over the previous centuries. Yes, centuries — for what are carrier pigeons but a means of aerial liaison? Besides, man had been airborne long before the Wright brothers added an engine to the flying machines. Hot air balloons and kites had been used long before powered flight began.

The L-4 was a cheap yet very reliable aircraft already popular with pilots in its Piper Cub form, thus it provided the US military with an almost off-the-shelf solution that was perfectly suited for the liaison and observation roles. Not fast, not armed, not even armoured, the L-4 was one of the smallest warplanes of the time, yet a good observer in the back seat could bring down more firepower onto an enemy position than any other warplane at the time, making this plane a vital asset to the US military.


Its predecessor (and successor), the Piper Cub, is an evergreen favourite with flight simulation fans, so how does the L-4 meet the standards set and how does she perform in FSX? Against the backdrop of a photo-real Hawaii scenery in the screenshot here, you could easily imagine this little warbird flying over some Pacific island with the observer in the back seat sending out position reports of Japanese ground forces…

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So how does the Flight Replicas L-4 Grasshopper stand up to the simmer’s needs?

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Download and Install

Wherever you decide to buy this aircraft, your purchase will give you a download of just under 200 MB to park on your hard drive. As it is an ‘exe’ file, installation is as simple as double clicking the installer and following the on-screen instructions. Once finished, the L-4 will use almost one and a half gigabytes of hard disc real estate. That’s quite some package!

A CD backup version can be bought in the simMarket shop

Words of caution:

1. The installer will offer a pre-written path to FSX. If you have installed FSX elsewhere or you have Vista 64bit installed, you should check the installation path and make sure.

But otherwise installation is no-nonsense and finished in a couple of minutes. Once installed, you will now have 4 new airplanes in fourteen paint schemes (I’ve already added a paint of my own and there will be a few screenshots later on in this review)

Let’s fire the sim up, pick a version, an airport, a time of day and let’s go.

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First Look – Exterior

loading-issuesAs usual, we really want to jump in and fly our new acquisition, so fire up FSX and…

The first thing an unsuspecting user might notice is that as FSX opens this plane, you will see only a black model at first. In the words of the Hitchhikers Guide to the Galaxy: Don’t Panic! After a few seconds wait — depending on your system and RAM configurations, the plane will load. A swift look at the aircraft texture folders reveals the reason: there are several very large texture files involved.

The developer has used 32 bit dds textures for this plane and also 2048 pixels square textures for the wings and fuselage. This means that the sim must load up to 95 MB of texture data for each model — and that is quite a lot for such a small plane.


Does all this amount of data affect performance?

Not much at all — on my ‘lower to middle of the road’ PC system. With a caveat of course: it really does depend where you are flying! Over “mega-cities” you will find your PC slowing down. As with all “performance issues”, check the sales information for minimum requirements and make sure your PC is up to the workload. In a similar vein, I know that someone from Flight Replicas will read this: It might help to provide a second set of “low resolution” textures, i.e. all textures in SDK standard 1024 pixel squares in DXT5 dds formats.

But if anyone feels that they would like “lighter” textures, simply open them in DXTbmp and resize them to DXT5 dds and 1024 pixel square.

But back to the walk-round…

reviewl4_17Walking round the plane, the new owner will be impressed by the level of detail that has been put into the “Grasshopper”. For one thing, the crew figures do score as a couple of the most lifelike we have had in any version of Flight Simulator. The model has been well detailed, even down to the undercarriage leg attachments and the tail wheel mounts. Even the dirt “spatter” from the wheels on the undersides of the wing has been “painted in” and the cables, pulleys, bolts, turnbuckles, cowling securing pins all add to the visual experience of this model.

As you progress around the exterior, you will find a lot to be happy with. The model has been exquisitely finished and there are enough details to more than satisfy us critics. The surface has been nicely bump-mapped, although from a personal viewpoint, I would have liked to have seen the detail that causes “bumps” painted on the textures as well, because the model does seem slightly two dimensional under certain lighting. Merely the addition of “rib tape” and stitching will give the model more “depth” — as you can see from these two pictures. I must hasten to add here, that my new paint is only a demonstration here; it will need to be tailored in to the existing bump-maps. But more of the painting later.

Another attraction of the exterior model is the way the metal parts are mapped with a different texture to the non-metallic parts. Whether this was by design or accident, only the developer can say, but I did like the way the canopy edge strips appear as painted metal and the canvas is duly more matt in appearance.

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Second Look – Interior

Now it is time to jump in and have a look at the office…

Depending on the model you have chosen, you will find yourself in either the front seat (military with an observer in the back) or in the back seat of the civilianised variants.

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One thing that is noticeable — by its absence unfortunately — is the lack of camera angles and views. This is rather a disappointment really, because the model is just so well detailed — especially the interior / VC — that it just cries out for different viewpoints. Maybe someone from Flight Replicas is reading this? Can we have a small patch here as well please?

The L-4 cockpit is most definitely not a tech-freak’s ideal. The instrumentation is basic, to say the least. But hey, we’re talking nineteen thirties aviation here; the ‘barnstorming’ years; it is a VFR only plane after all. On the other hand, the developers have produced some beautiful dials and needles here and the clarity and reflections on the gauges makes for really enjoyable “eye-candy” flying in VC mode.

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Looking around the cockpit some more, the new user will not fail to be pleased by the small details — such as the rudder control cable swaging and shackles, or the texture of the “driver’s seat” in the civvy version. Although the detail is perhaps a wee bit too good… Pardon? You read me right dear reader. The detail is so good, that as an aircraft engineer I really ought to tell the developers off because they forgot to insert the split-pin into the castle nuts that secure the rudder cables to the pedals — tut tut and harrumph!

…and a big plus point to the developers for going to this level of detail…


Another plus worth mentioning here is that the L-4 has separate brake pedals mounted slightly inboard of the rudder pedals. So all you sim-pilots with rudder pedals be aware that the “realism” is different here. I guess that real L-4 pilots steered this plane on the ground by “heel and toe” method.

With such a simple office, there’s not much more to describe, so…

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Let’s Go Flying

What can we say about the L-4? You’ve probably all flown the FSX default Piper Cub by now, so this plane will be very familiar to you. It’s a taildragger, so taxiing and acceleration does need a careful hand on the stick.

The Cub / L-4 is known to be sensitive and prone to tip forward if you have the balance slightly towards the nose. There are a few “nose-over” videos on You Tube that even show this tendency. So when taxiing always pull the stick right back and keep your speed down to a brisk walking pace — of course, that’s s.o.p. in a taildragger anyway. Also be careful when braking, because the L-4 will cause you plenty of propeller repair bills if you aren’t careful.


Otherwise, the model’s ground handling is relatively straightforward. She responds very nicely to rudder and brake steering, so lining up on the runway is no big deal if you are used to the taildragger habits.

Opening the throttle, the L-4 accelerates neatly and with the expected “taildragger twist”. You need to correct the prop wash and torque with your rudder, but as soon as the tail lifts, you must relax otherwise you will find yourself shimmying down the runway like a Brazilian Samba dancer in the Samba-drome on Mardi Gras…

The L-4 lifts her tail quite rapidly too and you are airborne quite soon, climbing away at a healthy rate of climb. Too healthy perhaps? I hesitate to say this, because I have never flown in a Cub, but I find that for such a relatively low powered aircraft, she does appear to be a lot more nimble than other planes with better performance. Having said that, it does not reduce flying pleasure in the slightest. The Cub / L-4 was renowned as a pleasant aircraft to fly and this FSX model is exactly that.


AFTER-NOTE… I have exchanged mails with the developers and I am assured that this agility is as it should be. Looking at the wing from an engineer’s point of view, I have to agree that it is indeed a high-lift wing, so climb performance does look good. Besides, with a full fuel tank you still have enough capacity to carry two adults and still not be above max AUW.

STOP PRESS FEEDBACK — A direct quote from the developer will suffice here: “Pilots describe the 95 hp versions as climbing like a ‘homesick angel’, and they take off in the three-point attitude, before the tail even has time to come up. 65 hp versions are a little slower, especially with two on board plus clunky mil radio.”

In fact, there isn’t much negative to comment on this plane’s flying characteristics at all — she flies as sweetly as the default cub — and that is exactly as it should be. Even if you treat her rough, she’s forgiving — just set trim in neutral, let go of everything and pull the throttle back even… she’ll recover from just about anything you can throw at her if you have enough height. On the other hand, you shouldn’t treat an L-4 the same way you might handle an aerobatic biplane anyway!

The FSX model will loop, stall, spin and even side-slip after a fashion. You can even manage passable tail-slides and chandelle turns if you put your mind to it, but remember — nothing violent please… Putting the aerobatics side, I did however, find the side-slip characteristics too weak. This plane has a good amount of rudder and reasonable control around the roll axis, so both yaw and roll priority side-slips could be better and she should come down a good deal faster.


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Once you have installed the L-4, you will find both a 22 page pdf and an MS Word doc hand-book for the L-4 in the Grasshopper AGF folder (C:\Program Files\Microsoft Games\Microsoft Flight Simulator X\SimObjects\Airplanes\L-4 Grasshopper AGF)

The manual covers operating techniques rather briefly — you don’t really need much more anyway and if you do, you can use the Flight Simulator reference documentation. But still, the standard procedures are described well enough.

But what I liked most about the manual was the inclusion of a foreword by Ken Wakefield, author of “The Fighting Grasshoppers” and “Lightplanes at War”. This and other background information about the L-4 make the manual very interesting to read. Also worth mentioning here are the various links to further research material on the Internet.

The manual also includes numerous screenshots with markers that point out the various knobs, levers and dials you need to know about and the “how to” parts are clearly written and easy to follow.

All in all, the manual is good enough to meet the needs of most users. There are several very useful links on the first page that will take you to some very informative online pages and I would like to add one of my own here:

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howto1Having already survived the “first flight”, I shall now take a closer and more critical look at the handling. Wherever I can, I have searched for as accurate original data as possible so that I can make a fair and justifiable comparison between the model and a real L-4 / Piper Cub

If you search the web, you’ll find copies of a very early (1940s?) 32 page pamphlet that tells you “How to fly a Piper Cub”. Considering the first 12 or so pages are filled with descriptive text about how to read the booklet and what other Piper Cub variants there are, and that a lot of the “Tuition” is covered by black and white photos, one wonders just how we humans managed to survive those early years of flight…

One particular graphic does make the reader chuckle:

howto2The last page of the pamphlet shows simple drawings of a flying instructor and the page title is “Learn what your instructor means by these hand signals”. The commentary under the last picture on the page says “14. Taps student on head — PLEASE release controls to instructor” and the picture shows the instructor giving the student a rather “firm tap” (actually “Whack” springs to mind — just goes to show that you didn’t mess with your instructor even then…)

But if you follow that guide, you will learn how to handle your L-4 properly — by the standards of the day of course.

Now let us take a look at the handling — from “Cold and Dark”. I did a search and found some performance data for the Cub (which is basically what an L-4 is):

Piper J-3 Cub – Performance Data:

Horsepower: 65
Gross Weight: 1220 lbs
Top Speed: 76 kts Empty Weight: 680 lbs
Cruise Speed: 65 kts Fuel Capacity: 9 gal (L-4 = 12 US Gal)
Stall Speed (dirty): 33 kts Range: 146 nm
Takeoff Landing
Ground Roll: 370 ft Ground Roll: 290 ft
Over 50 ft obstacle: 730 ft
Over 50 ft obstacle: 470 ft
Rate Of Climb: 450 fpm Ceiling: 11500 ft  

Taking the data above and following the Flight Replicas manual (and the procedures in that “How to fly a piper cub” pamphlet) I set up a cold and dark saved flight at my current favourite airfield — Plum Island.

The results and comments I give here are now from personal experience. I do add some subjective commentary, but this is based on a few decades of aeronautical experience and almost as many in this wonderful hobby of ours.

Operating all the switches, knobs, dials and levers (e.g. setting the altimeter or cracking the throttle) is done by using the mouse (click or scroll wheel). If you have a programmable joystick system, you can use your own pre-programmed options.

Starting the (simulated) L-4 couldn’t be simpler — there’s an invisible man who swings the prop for you after you turn the ignition to “start”. Oil pressure is there as soon as the engine turns and will remain more or less constant until the engine is turned off unless you have any “failure systems” active of course. One slight (possibly subjective) comment I shall make here is that the oil temperature was at over 100 ° F even though it was a cold and dark start on a winter’s day.

Operating the magnetos to check the mag-drops is a tricky affair. The switch animation is rather sensitive and you can easily turn the engine off. I guess that needs a bit of practice.


As I have already commented, the instruments are a sheer delight to read — the gradations on the dials are very crisp and even flying from the back seat, they are still easy to read.

Taxiing from the VC is not too difficult if you keep your speed down. Lining up on the Plum Island runway is easy, simply being a case of aligning the left and right edges of the runway with the forward lower corners of the side windows.

Applying power smoothly, you will find that the tail swings to the right (prop wash/torque reaction) and lifts very quickly, so you will have to have your hands and feet at the ready to compensate. Ground roll and 50′ clearance are both achievable within the numbers above, albeit a tad too easy for my personal feel.


Maybe that is a subjective statement. I did, however, run my stopwatch alongside the take-off and climb. The performance data above gives rate of climb as 450 fpm at best climb speed of 55 mph. I achieved 500′ to 1500′ (after stabilising my climb after take-off) in 47 seconds. And I didn’t have the throttle against the front stop. 5000′ to 6000′ took 70 seconds and 7000′ to 8000′ was still a respectable 95 seconds.

After the climb out, the throttle can be eased back to cruise power (2100 rpm) and if you trim the plane out, she will fly sweetly at around 65 Kts / 75 ish mph. Now that is on the numbers indeed.

I next took the time to check out service ceiling — in the real world this is merely a number in the book and does vary according to atmospheric conditions. On one flight over the Grand Canyon I managed to chase the L-4 to just a whisker over 14000 feet, which is rather more than the given 11500 feet service ceiling given. On a second climb over Massachusetts (for this part of the review) I took a screenshot at just over 14200 feet — the plane is still climbing as I write this: 14555 feet, 55 Kts, 2200 rpm…


STOP PRESS FEEDBACK — The developer states that climb rates are as they should be. All I can say is that the figures I recorded above are taken directly from my PC and I used a stop watch to record the climb times. Maybe I have the wrong datasheets? Also, I am currently at 15225 feet and still climbing — albeit slowly — over Massachusetts and Plum Island


I should also add that the pamphlet “How to fly a Piper Cub” gives the absolute ceiling (solo) as 14000 feet and the full load rate of climb as 450 ft.

Other things I noticed:

The real L-4 has no lateral trim. Only elevator — so I was rather surprised to find the FSX “native” keyboard (and by association, the joystick) control assignments still work.

In the denser atmosphere, I flew the L-4 at maximum throttle. Trimming the plane out to stay straight and level, places the plane in a marked nose-down attitude. At first this seems a bit unusual, but on analysis it is likely. If any real world pilot could check that out (F-R developer perhaps?), I would be grateful; because as a glider pilot, nose down is “normal for me”. And in helicopters even more so… and from my other aviation experience I do know that an Airbus cruises with its nose 3° up.


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The 3D Model and Textures

Ah… now we get to the area closest to my heart: the painter’s end of this add-on!

The model itself is well mapped to the textures, all animations are smooth and detail is excellent. Performance is good in all FS modes, i.e. DX10, DX9, from the VC or from outside. Flight Replicas do confess to using the FS default Piper Cub sounds, but that really is understandable and acceptable in anyone’s books. There is no 2D panel – but who needs one?

I seem to say this about every fabric-skinned plane I have tested (bar one) — I do miss the appropriate modelling of the wing surfaces that a certain freeware plane I know well has. It would be nice to see the 3D model wings shaped so that the wings are slightly concave between ribs. But in saying that, I will also forgive Flight Replicas, because they do make excellent use of bump-maps to simulate this wing shaping.


But with such a beautifully crafted 3D model, any complaints I have might sound unreasonable. After all, it really is a pretty model and the paints that come with it are really well done.

The texture file size has been commented on already. Moaners and groaners will shout that this causes a big loss in FPS. Yes, FSX does have to load a heck of a lot of MB of texture into the sim when the plane is loaded, but as I have so often commented on many other planes, once loaded, file size doesn’t really cause that much of a problem if you have a goodly amount of RAM and a good CPU. The developers have made the L-4 textures in 32 bit format and have made a couple of the textures 2048 pixels square. I do think they would be well served to at least provide a re-drawn set in DXT5 format as this will reduce the load by a factor of four.

I do have one other issue here, and that is the propeller disc. With all the work that has been put into the model and the textures, Flight Replicas certainly didn’t make a “moving” prop disc. All you see out of the cockpit is a transparent grey disc that doesn’t appear to move. I am not a “props painter” myself, but a few simple dabs with the paintbrush and it looks a lot more FS-like already. By putting an ever so slight offset on the texture, I now have a slight wobble and shadow visible. Although I hasten to add, that the model is more accurate with its almost static appearing prop disc.

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Flight replicas prop on the left, modified on the right.

STOP PRESS FEEDBACK — I will quote the developer direct here: “I am a GA pilot in real life, and the prop disk is what I see in real life (except at very slow rpm, which FSX doesn’t do well anyway). In fact, often it’s much more invisible than even that. The last time I was up in the 172, in a late afternoon, I couldn’t even see the edge of the prop disk at all, no matter which direction I flew! Many simmers are used to the film-and-photo prop textures, wherein you can see a blurred blade due to shutter speeds.”

I have to agree with his statements. As simmers we are indeed more used to the “TV screen blur” I have just cycled back through some of my own photos — I do have a few single engine prop-plane flights to my credit — and the developer is right of course: at flight RPM the disc does become as good as invisible — I will attach a photo of my own here.


How the prop disc is seen in the sim

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Two real-world shots looking forward out of the cockpit

I have only one other sadness to comment on about the textures and that is the lack of specular mapping. But I do write this here only as a matter of principle. The L-4 is a “rag bag” and as such, there is no real call for fancy polychromatic artwork on this plane. None of the textures have alpha channels either, but as there are no really glossy L-4s around, this does not affect the L-4 in any way.

The “Paintkit” included in this model is the icing on the cake though! Flight Replicas have included all the texture sheets in PSD and DDS format in a separate folder. The PSDs are all layered and extremely well commented so that painters of all levels can have success with their attempts to paint this plane. The Danish version (OY-ECV) you see in some of the screenshots here in this review was done by yours truly and I do think the results are worth including, even though the paint is not finished by a long shot.

STOP PRESS FEEDBACK — The developer is looking at the specular question as a matter of future reference. I also understand his personal reasons for applying the formats he has used. As users, we are not really missing out on this particular aircraft. So you need not expect any big changes made to the L4 here. Remember, we don’t need specs on this kind of aircraft model.

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If you like small planes you will just love this one. But even if you are a 747 captain, you will love this plane too! Even the tube flyers need a break and with this lovely little add-on the change is well worth it. Who knows… you may even re-discover the sheer joy of flight with this plane.

She’s perfect for low and slow flight around your favourite scenery.

I have made a few negative comments in this review? Yes, but none of them should really be seen as critical criticism. Most of the issues are easily passed off as limitations imposed by the fact that this is a simulation and we have to bear in mind we are dealing with a budget end simulator, not a full-blown, six-axis simulation machine. There are a few inaccuracies and a few small niggles, but on the whole, you really will have a lot of pleasure from the L-4

So please take the comments as encouragement to all developers reading this. This add-on sets very high standards for future releases.

I must also commend the developer on his input to this review. He has been very supportive, even where I have had to be critical.

The verdict? A “must have” for just about anyone.

Good job Flight Replicas! You don’t need to change things, despite the content of this review.

Almost a full five out of five really. I’ll go for four and a half.


Four and a half Stars out of Five

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The Summary in brief

What it can do What it can’t do Who will like it Pro Con
Fly low and slow Fly faster than about 100mph Simmers with highly detailed scenery addons Beautifully modelled Nothing
Act as a spotter plane in any military role “Shoot up the enemy” (although a well placed spot will give him a headache after the next artillery “dump”) Warbird flyers Excellent paintkit  
It’s a great little GA for fun flights Carry more than one passenger GA Flyers Fully FSX  
Fly daytime VFR Fly in the dark – no IFR or lights
“Butterfly” pilots (Those who only come out on a sunny day) Fair Price  
Give you a relaxing flight on your PC Cause you stress Airliner, combat and fast jet pilots will enjoy the rest    

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Various Screenshots (for thise with time)

Some comparisons to show how the bumpmaps work and why I advocate painting the “bumpy bits” onto the textures as well.

bmvspaint_1 bmvspaint_2


A couple showing how painted “bumpy bits” can improve things. First “Bump-maps only”


Now the Danish version with painted in bump-maps


…and here are two views taken with the plane at different angles to the sun:

bumps_1 bumps_2

Don’t you just love chromed rocker covers?

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The Test System


AMD FX62 based
Foxconn AM2 Motherboard
3GB Corsair RAM
nVidia GeForce 8800 GTS graphics, 512 MB VRAM
Realtek onboard 8:1 sound
three x 250 GB SATA2 Hard drives


Windows Vista Home Premium, 64 bit

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About The Author

maninplaneChris ‘Eagleskinner’ Brisland is an aircraft engineer with flight experience. He was knitted over half a century ago and at his current age has collected quite a few books, videos and T-shirts. A simmer since the very early days of “PC Flight”, he has a broad knowledge of flying around bedrooms, studies and home-offices. You will often find him at his desk thinking up new paint schemes for sim-planes — “finger painting without the mess”. Find him online at the simFlight Forums and many of the other places flightsimmers lurk.

He’s still not come unravelled by the way, so don’t pick at any loose ends you might find…

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0 Responses

  1. Dear Chris!
    Very, very impressed by the wonderfully detailed L-4.
    I am the guy who owns and flies OY-ECV. My son Chris who is a PC Game Concept Artist hand-painted the (very) Vargas inspired nose-art “Mistress”.
    I did modify the scheme a year ago, so now it has 357th FG paintjob with code B6-4 (see: 357th FG DID have L-4s, but I have been unable to prove that they did in june 1944. I have only seen pictures of silver ones from 1945. However I thought that it would look good (!), and I also wanted to honour triple ace and extremely nice gentleman Col. “Bud” Andersson whom I have met twice, latest at Gathering of Mustangs and Legends at Rickenbacker, OH in Sept. 2007 where he took time for a long chat with me when I presented him a print of my sons painting of 357th FG ace Lt. William C. Reece (KIA) flying P-51B C5-F “Bear River Bets” (see Chris’ website:
    Once again: Impressive L-4 details. Keep up the good work guys!

  2. Hi Chris:

    Thanks for the great review. I decided to buy the L-4 packages (wheels and floats) based on your review and was delighted (I flew a J3C90 on floats).

    I love your “Mistress” repaint. Any chance it’s available for download anywhere? I searched but couldn’t find it.


  3. Hi Mike,

    It’s on Avsim and they are back online with the file library.

    Hope that helps.

  4. Hi Chris:

    Thanks for the help!

    Unfortunately the AVSIM download link says that the file is unavailable (hasn’t been restored).

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