The Sorta P-38is based on a concept first shown to the builder/author (above left) by accomplished freeflighter, Pres Bruning. Built using a pair of the venerable AMA Cubkits, the model makes a fun multi-engine model for indoor or outdoor fun. The center section of the wing is reinforced using a pair of short pieces of 1⁄16× 1⁄8-inch balsa installed at the bottom of each end of the wing root
cause the solvent to slightly dissolve the ton- er, transferring it to the balsa. Let the MEK evaporate for a minute or so before moving the paper, or you risk smudging the mark- ings. The softer the balsa, the more likely you are to see some bleeding around the lines, so to get a sense of how much MEK is needed, you may wish to practice this method using a different photocopy on a few scrap pieces. You can usually get one good printing out of a copy. After that, the mark- ings get rather faint. After doing one side, cut the pod out. Af-
ter smoothing the edges with sandpaper, carefully align the other piece of paper to apply the markings on the other side. Con- nect the left and right side markings around the edges using your favorite mark- ing method, either a soft art pencil or per- manent marker. I added nose art to my Sorta P-38 by printing it on matte finish clear mylar shipping label material, print- ed on a computer ink-jet printer. A few quick trims around the perimeter with a hobby knife, and it looked like it was paint- ed in place. A light dusting of Krylon matte finish
spray, or their Workable Fixatif, or other artist’s spray, will keep the markings from running if your printer’s ink is not water re- sistant. A dusting is the key—you don’t want to induce warps at this point! Cut the slot for the wing root in the pod.
Take care to do it accurately, as the section that extends to the horizontal tail must be aligned with the underside of the tail, and a poorly aligned slot will throw off that alignment. To assemble the Sorta P-38, carefully
mark each boom 11⁄2 inches from the front, which will be the location for the leading edge for each wing. Glue the wings onto each tail boom, so that you have a left and right boom with an inner and outer wing panel glued to it. You’re not going to install the fuselage pod
at this time; that happens only after the wings, tail booms and tail are assembled and have dried. The inner panel should be flat in relation to the other center section wing. Butt the wing roots and align their edges (but don’t glue their edges together just yet!). Tape them together on the under- side with a couple of short pieces of masking tape.
Using a piece or two of scrap balsa sized
to match your motor sticks (typically 3⁄8-inch tall), hold the wing roots off your building board. Pin each wing in place, check the alignment of the entire structure, and at-
FLYING MODELS
slot in the fuselage pod (above center). Tracing paper printed on an inkjet printer provides the markings for the fuselage pod (above right). Installed using a gluestick, the markings can be dusted with a light coat of artists varnish to ensure they won’t run or wear off. One can even add some personality by adding “nose art.”
tach the horizontal tail to the aft portion of the booms, pinning it in place after you dou- ble-check its alignment. Pin the booms down on a flat building board, and allow to dry. To help reinforce the center section joint
and ensure it’s flat, add a pair of 1⁄8×1⁄16-inch balsa reinforcements at each end of the wing root slot (see the photo). Make certain they are straight. Once dry, slip the fuselage pod in position, cementing the wings in the slot while also gluing the boom to the horizontal tail. It could be argued that the pod doesn’t
have to be attached to the tail, but Pres Brun- ing and I both found that the structure was much stronger when it was built as depicted. Otherwise, the wing structure tended to be a bit floppy when all that rubber horsepower is applied by those twin motors. I also added a vertical corner gusset at the leading and trailing edges of the wings, reinforcing the joint between the outer wing panels and the booms. A round sanding stick was then ap- plied to trim away some of the gusset. Make a pair of rear motor hooks made
from short lengths of 0.032-inch music wire, or a couple of pins. Bind them with thread and glue them in place. You can add a short balsa tail skid at the ends of the tail booms if you wish. You can certainly build your Sorta P-38 without any kind of landing gear, and it would be a real going machine. But a flight off the ground is always fun, so I’ve chosen to equip my two versions with wheels. You can build the landing gear one of two
ways: On my first Sorta P-38, I chose to in- stall the gear legs further aft, well behind the prop hangers. That avoided any inter- ference with the prop hook and the landing gear. Or, you can bend an additional offset in the gear and install it using the prop hanger’s built-in landing gear slot. In either case, bend each landing gear leg to shape, add a wheel on each, and install them on the booms. While installing each of the props and hanger/landing gears on the booms, I used a dab of epoxy inside the hanger, just to en- sure the props don’t fall off. When he was younger, my son, Alden, and his friends thought it was hilarious when his Guillow’s Strato-Streak based version of the Sorta P- 38 would seemingly self-destruct every time it landed as the props, landing gear and rub- ber would all fly off in different directions upon impact, the aeronautical equivalent of the Rock-em, Sock-em Robots! This type of model invites modification, and one of the most obvious would be the
use of a tricycle landing gear to match the original airplane’s configuration. That’s what I did for the blue version you see in the photos. The main landing gear should be lo- cated just aft of the cockpit when viewed from the side. I added a piece of hardwood dowel rod to the fuselage pod to reinforce the area where the nose wheel is plugged in place. Just be sure to keep the wing at a slightly positive angle of attack when the airplane’s at rest on the ground, or the ground run will be excessive. Another change would be the carving of a pair of counter-rotating props. If you’d like, you can add a simple motor
stop on one boom so that you can wind your Sorta P-38 using your standard winding stooge and a wire coat hanger hook looped through the prop hanger. On the Sorta P-38, I just use a large alligator clip with a 3⁄32-inch dowel rod attached and sticking out far enough to stop the prop. A length of bright- ly colored ribbon or yarn tied to the end helps you find it when it gets dropped in the grass! I have found that winding the left motor
just a few more turns than the right helps prevent the left wing from coming down a bit too far during the initial power burst. The Sorta P-38 ROG’s beautifully, quickly gain- ing altitude as it banks around to the left when flying indoors. You can adjust the pow- er portion of the flight by tweaking the prop hangers to change the left/right thrust of each side; you may find, as I did, that a bit more right thrust was used on the right en- gine (as viewed from above) vs. the left en- gine. In either case, be sure to remember how many turns you put in each side, or your P-38 jockey may be in for a wild ride!
A fairly simple modification is to make it a tricycle landing gear version. The main wheels are moved aft along the booms so the airplane sits with just a slightly positive angle of attack when the nose wheel is installed.
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