RCU Review: Great Planes P-38 Profile

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    Contributed by: Mike Buzzeo | Published: June 2004 | Views: 47894 | email icon Email this Article | PDFpdf icon

    Review by: Mike Buzzeo (MinnFlyer) Email Me

    Great Planes
    Model Manufacturing Company

    P.O. Box 9021
    Champaign, IL 61826-9021

    Window Media Player
    Dragon 40 ARF

    Die Cutting:
    Ease of Assembly:
    Completeness of Kit:
    Balsa Quality:
    Basic Flight:
    Advanced Flight:
    Stall Characteristics:

    • Fast Easy Assembly
    • Good Quality Throughout
    • Excellent Parts Fit
    • Very Nicely Engineered Throttle Setup
    • Quality Hardware
    • Photo Illustrated Step-by-Step Instructions
    • ABS Center Pod Makes For Easy Assembly

    • Cutting trailing edge to size (See Text).
    • Typo on Metric CG Location.

    There were many great fighters from the WWII era, but none with such distinguishing looks as the Lockheed P-38. Designed in 1937 by Lockheed's Kelly Johnson, the P-38 brought a new dimension to WWII fighters... A Second Engine! With liquid cooled engines, the slightest nick in a coolant line would result in a seized engine in a matter of minutes, which for most fighters was a major concern during low-level missions. A second engine was a second chance to make it home again.

    The "Forked Tail Devil" in all it's glory!

    After going through a few design changes, as well as "growing pains" in the production stage, the P-38 "Lightning" was in full production by the early 40's. Late in 1942, it went into large-scale operations during the North African campaign where the German Luftwaffe named it "Der Gabelschwanz Teufel"--"The Forked-Tail Devil."

    By the end of its production in 1945, almost 10,000 P-38's had been built in models varying from the original to the two-seat/radar equipped P-38 M by the wars end.

    Whatever the configuration, the Lockheed P-38 is by far one of the most recognizable planes of the era, but modeling one has never been an easy taskā€¦ Until now! Great Planes has put this WWII Classic into a new class by creating the new "Profile 38".

    I would also like to add, that it is an honor and a privilege to bring you RCU's first KIT Review!

    Name: Great Planes Profile - 38

    Price: $99.99

    50" (1270 mm)

    Wing area: 416 sq in (27 sq dm)

    Length: 36.75" (933mm)

    Weight per Mfg: Total: 4-5lbs (1810-2270 kg)

    Actual Flying Weight: Total: 5.48 lbs. (dry)

    Skill level: Intermediate-Advanced

    Radio Used:
    Futaba Sky Sport Transmitter
    Futaba R127DF FM Rx
    (6) Hobbico CS-55 Servos Servos for Elevator, Rudder, Ailerons (2), Throttle, Nose Wheel

    Channels Used: 4 total - elevator, aileron, rudder, throttle

    Battery Used:
    1 SR 4.5V 600 Mah NICD

    Prop Used: Master Airscrew 9x5

    Required to Complete:

    • 4-channel radio with 6 servos
    • 2 Servo Wire Extensions
    • 2 Servo "Y" Cords
    • CA glue
    • 30-Min epoxy
    • Loctite thread lock
    • Fuel Tubing
    • (2) .15 -.25 2-Stroke Glow Engines w/ Spinners and Propellers
    • 2 Rolls Covering
    • Standard building tools

    After having reviewed so many ARF's, the Profile 38's box seemed almost comically small at first. Once it was opened, it was easy to see why. Every sheet, stick, and package was neatly laid out, with two sets of rolled plans, the manual, and the ABS parts arranged on top.

    An inventory, and inspection reveled no missing parts, and the die-cutting proved to be, at first glance, excellent. Throughout construction, only a few parts needed any sanding, as most easily pressed out of their frames.


    The 48 page Manual is everything you have come to expect from Great Planes. The instructions are step-by-step, with photos at almost every step to guide you along the way. I would have given an excellent rating on the Manual, but I did notice two typos that could be confusing. In a photo on page 8, the leading and trailing edges of the Stab are mislabeled, and on page 42, there are 2 diagrams showing the placement of the CG; In the first of the two, the 4" measurement is incorrectly converted into Metric Units as "120mm". However, in the second diagram, the correct conversion of "102mm" is shown.

    (editors note- Great Planes has posted tech notes on the website and will be correcting the manual before the next printing.)


    We start out by cutting the leading and trailing edges of the Stab, and pinning them to the building board. I am using a ceiling tile on top of my building table to facilitate the pinning. Once the LE and TE are pinned down, each spar is cut, and glued in place with thin CA.

    Once the Stab Frame is complete, the Trailing Edge Tips are sandwiched together with medium CA and glued to the outboard ends of the TE.

    Next, the die-cut pieces for the Stab Tips are also sandwiched and assembled. I like this sandwich arrangement in that the wood grain on one piece never lines up exactly with its mating piece, which adds tremendous strength to the finished parts.

    Finally, a piece of 1/4" sheeting is cut to fit the tip to provide a joiner tab for the tips.

    With the Stab pieces complete, it's time to assemble the Elevator and Rudder. Like the Inner Stab, the Elevator is a simple stick construction, while the Rudder is a combination of die-cut parts and sticks like the Stab Tips.

    After the Tail pieces are assembled, each part is given a good sanding to assure that there are no uneven edges.


    Wing construction starts with the lamination of the ribs where the Booms will attach. In most respects the construction is similar to most wings, but there are several noteworthy points. First, the Profile-38 uses an amazing one- piece shear web system. Combine that with the trailing edge/wing jig, and this wing almost defies being built anything but straight. About the only thing I could complain about, is that the Trailing Edge Jig, as nice as it is, could have had some cuts along it to aid in cutting it down to its final size.

    Unfortunately, I lost several pictures of the wing construction, but it can all be seen right in the manual which can be downloaded in PDF form here.

    Once the Gear Blocks and servo tray is installed, the wing halves are sheeted, and joined..

    Once joined, a Torque Rod Throttle Control system is installed in the wing. This is very well thought out, and easy to assemble.

    Next, the wingtips, and Leading edge are glued in place.

    The ailerons are cut and sanded to shape, as is the leading edge and wingtips. At this point, the Wing construction is done..


    The Boom construction starts with laminating the components together. Once assembled, they are laid out on the plans and joined with 1/4" square balsa sticks. The sides are sheeted, and the sheeting is cut out for the Wing and Engines.

    Once both Booms are built, the top sections are completed. Next, the engine mounts are laminated together, and epoxied in place.

    Great Planes provides an offset gauge, and each engine gets a different offset so that they both face 4 degrees outward to help keep the Profile 38 flying straight in case of a single engine flameout.


    Once the epoxy has set, the recessed sides of the engine mounts are filled with scrap sheeting and Balsa Filler, then sanded smooth.

    The engines are then placed into position, and the mounting flanges are marked on the balsa-filled area. Then the mounting holes are marked and drilled.

    With the engines removed, the balsa filler is removed from the mounting flange area so that the engines will sit directly on the slanted plywood mount.

    O.S. .25LA

    O.S. .25 LA w/Muffler Blue

    THE O.S. MAX-LA Series has been developed to meet the requirements of beginners and sport flyers. Their modern design incorporates a remote needle valve unit mounted at the rear, where adjustment is safely away from the rotating propeller. They combine low cost with reliability and ease of handling. Like all O.S. engines, they are built to standards of engineering excellence that have evolved through more than 60 years experience in the design and production of model internal-combustion engines.

    Advanced modern precision machinery, top quality materials and the efforts of highly skilled craftsmen and technicians are combined to ensure a continuation of the levels of performance, durability and reliability for which O.S. is world famous.

    • Bore: 0.709" (18.0 mm)
    • Stroke: 0.630" (16.0 mm)
    • Displacement: 0.249ci (4.07 cc)
    • Practical RPM Range: 2,000 - 16,000rpm
    • Weight: 6.54oz (185.5 g)

    Other significant features include: bronze bushings for low-friction operation, a flat prop washer and longer crankshaft that provide more thread to engage, and a squared heat sink head and added fin area to increase cooling and enhance performance and longevity.

    O.S. recommends using a fuel with 5%-15% nitromethane with 20% lubricant. Synthetic, castor, or a synthetic/castor blend may be used, but they warn against using fuels with less than 18% lubricant.

    Props recommended by O.S. for the .25LA range from a 9x5, to a 9x6. I used an 9x5 Master Airscrew Black Nylon Prop for all flights.

    At this point, the Booms, Stab, and Wing, come together as a single unit. And BOY, it's starting to look good!


    Like the other assemblies, the Center Pod pieces are first laminated together, and then the Frame Doublers are added, followed by the Canopy Alignment Disks.

    The Servo Tray and forward Bulkheads are added next, followed by Bulkhead Doublers. Once the assembly is complete, the Nose Wheel bearings are screwed into place.

    The entire assembly is now epoxied to the wing. An added support is glued in place atop the wing.

    Once this is ready, the molded Center Pod is placed on the frame, the bottom half is mated to it, and the top and bottom halves are glued together forward of the bulkhead. The rear of the bottom piece is then cut off, and tabs are glued in place for securing it once the Radio is installed.


    The Aileron Servos are secured in the wings, and balsa sticks are glued around them to form a frame for the covering to adhere to.

    The Rudder and Elevator servos are then installed in the Booms, and the dummy radiator cover mounts are taped in place around them. With the mounts in place, the tabs that will secure them are glued to the booms. The mounts are then removed.

    Holes are then cut into the booms to allow passage of the Servo wires, and with the pushrods hooked up, the Pushrod Supports are positioned (but not glued until after covering).

    Finally, the Throttle, and Nose Wheel Servos are placed into the Center Pod Servo Tray.


    Covering is never an easy task, and the Profile-38 is no exception. In fact, due to its intricate design, it was one of the tougher kits that I have covered. Not incredably difficult mind you, just more complicated than most (Of course, this is to be expected with ANY twin boom design).

    Great Planes did, however give very detailed instructions on how to seam the colors together for the "Invasion Stripes". I used the technique on the white and silver, but since the covering I was using was MonoKote brand, I opted to add the black stripes later by applying them with "No Heat" Trim Solvent.

    The Canopy and Radiator Covers were masked with 3M Fine Line tape, and painted with LustreKote Paint which matched the MonoKote perfectly.