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Comet Industries P-38 Lightning

[IMAGE] Known by the German Luftwaffe as "Der Gabelschwanz Teufel" (The Fork-Tailed Devil) the P-38 Lockheed Lightning was light years ahead of its time. Designed as a high-altitude interceptor, contrary to what some think, the P-38 was not just a fighter; it also carried high explosive and incendiary bomb loads -- competing with the early WWII bomber aircraft (with bomb loads of up to 4000 pounds). It was the fighter of choice for pilots.

Approximately 10,000 P-38's were built, and they flew in every combat theater, around the world during WWII.

In steep dives, these aircraft could reach speeds above Mach 0.75 (called transonic). At transonic speeds, air in front of the wings became compressed and reached supersonic speeds as it flowed over the wings, forming a shock wave. This resulted in an increase in drag and a decrease in lift.

Another result was the movement of the wing's center of lift to the rear, forcing the aircraft to rotate so that the nose moved downward and it went into a steep dive. Pilots found that that their aircraft would not pull out of this dive. When they attempted to pull out, they found the control stick, as one pilot put it, "was cast in about two feet of concrete." In some cases, the airplanes crashed or broke up in the denser air as they approached the ground. In other cases, the pilots were able to pull out of the dive. These accidents and near misses reinforced the popular belief in a "sound barrier." The need for data at speeds near that of sound and the inability of wind tunnels at the time to provide it would lead to the construction and flight of the X-1 and D-558 research aircraft.

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25 years ago, wondering around town, I stumbled upon Hobby World on the west side. I hadn't played with a wood model airplane in years, but something made me pick up the Comet Industries P-38 Lightning kit they had on the shelf. I think it was the fact that it only cost $6 bucks, compared to the price of the Guillow's planes they had there, but I bought it and a tube of glue and a small bottle of airplane dope. Home I went, convinced that I'd be having lots of fun in the days to come... On the way home I stopped off at the drug store, and bought a package of single edged razor blades, and a box of straight pins. I knew all there was to know about stick and tissue airplane model construction, or so I thought. Once home I couldn't wait to open the kit box and see what was what.

[IMAGE] Imagine how pleased I was to find that the kit consisted of balsa planks with the the ouline of the parts printed on them. The concept of "die cut" seemed to have escaped these people. When I asked my dad about it, (he taught me everything I know about stick and tissue construction,) he told me that all kits were like this until the Guillow's people came along. So I bit the bullet and got started cutting the parts out with my single edged razor blade. It took weeks. Seriously. After cutting, sanding, notching, repairing, duplicating, and sanding some more, I was finally ready to start putting this thing together. At the time, my tools were limited, so hardwood dowel landing gear were impossible to work with. A 'gear up" configuration was perfect. I built it and papered it, and decided to NEVER, EVER buy a Comet model again. UNTIL...

About 5 years ago, as we began to learn how to blow up the plans for the various kts that we had accumulated over the years, I got to thinking about that dreadful P-38 kit I had built all those years ago. "Hummm... It couldn't have been that bad, could it?" So off to EBAY I went, after learning that Guillow's had bought Comet Industries, and shut em down. On EBAY I fould 4 original kits, and won all four auctions. The kits arrived, two of which were pretty much complete, one missing the plans, and one missing some parts. One had survived a house fire, but all were' buildable. As I built all fourkits at the same time, I templated all the parts as they were finished. Two planes were built "static" and two were built 1/2a U-Control. Once finished, I again didn't really want to mess with a P-38 again, EVER. UNTIL... Well, until now. I took one of the old plans, cut it up with the templates, into 81/2 by 11 chunks, and scanned them. I split each of the jpeg's into 9 images, retaining the 81/2 by 11 aspect ratio. We then printed the resulting images, achieving a 3:1 increase in aircraft size. (See the images above...) When we built the F6F recently, we used balsa. This proved be just too danged expensive for an aircraft this size, so with the addition of some Xmas tools, we bought, marked and cut a whole gruntload of 1/4 inch plywood into parts for the P-38...

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[IMAGE] It became obvious as we began construction on this project that the materials were strong and thick enough to employ screws in construction. As you would usually use a stick pin to hold various parts together in normal stick and tissue construction, we used a 5'8 #8 sheet metal screw to hold the parts. Stringer to rib, rib to structure. The result was a very strong method of assembly that was so sound that I was actually able to stand on the center fuselage assembly without damaging it! It also facilitated a quick and easy build. We built the wing in two pieces (halfs) and simply bolted them together with the proper dihedral. (6 inches) We added several stuctural stengthening pieces of 1/2 inch plywood in beteen the main fuelage and wing, and between the wing and booms on each side to allow us to screww the individual parts together. The plan is from an old Comet P-38 rubber powered plane, and strength in holding the plane together wasn't an issue. It became critical as we bgean to try to put the wing onto the main fuselage. Not to mention the booms. They weren't happy just hanging there on the wing. We screwed them on with sheet rock screws.

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[IMAGE] It came time to begin covering the plane, and for the most part it went very smoothly. At the encouragement of one of the guys on the Guillows Discussion board, I bout a book on Amazon about fabric covering on real airplanes. I discovered that cotton muslin is the right material, but shelac is the wrong dope. Btyrate Dope is the right stuff, and on the next plane, the Corsair, I'll be using butyrate. Apparently, butyrate will shrink the muslin. We'll see...

Haze Paint has been an unguarded secret for nearly 60 years. It's a camoflage story that has "slipped throught the cracks" so to speak. Having never been listed in any Technical Order, and having been withdrawn from use before the appropriate revisions could be printed, Haze Paint has been something of a mystery. Since the peculiar properties of the paint made samples impractical, color chips were never circulated. Though it was the standard high altitude photo reconnaissance camouflage paint scheme from March to October 1942...most will not even be aware of its existence...or the fact that it was applied to nearly 130 photographic Lightnings! However, if any camouflage ever achieved invisiblity...Haze Paint was it!

It was in the summer of 1940 when a prominent paint manufacturer named Samuel Cabot contacted that Army about a new white paint with "unusual properties". It was a colloidal solution of zinc oxide in oil originally know by his stock number L 31340. These "unusual properties" were the grains of pigment themselves. They had a diameter below the wavelength of blue or violet light, which causes a high reflection in these color ranges. This is known as the "Tyndall Effect." This is what makes our skies blue, and the purple of our mountains majesty. Cabot theorized that by spraying this pigment over a dark blue or black base coat, only blue and violet would be reflected...with all other colors of the spectrum being absorbed by the dark base coat. Differing angles of reflection would change the rate of absorbtion and theoretically match the ambient sky color. Although "invisibility" was not promised under all circumstances, it was felt that under certain weather conditions and lighting situations, that this scheme would yield favorable results.

Cabot took his theories to the Massachusetts Institute of Technology which was involved with a number of military related scientific projects. Their engineers found his theories sound and hence urged the Materiel Division of the Army Air Corps to institute full scale testing. It would not be until late December 1941 that these tests would take place.

The December tests of the new paint scheme were performed using a Republic P-43. These initial trials were encouraging as to the prospects of utilizing this new pigment. In March 1942, Lockheed was given instructions to paint all of it's F-4 Lightnings in Haze Paint.

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We didn't want to even get started with the expense of a gas powered engine large enough to get this thing into the air. Not to mention fuel proof paint, and other issues related to gas power including noise. So, electric power beacame the best idea. After searching the web for DC Electric Motors powerful enought to drag this airframe around the circle, we found that a hobby shop motor designed specifically to do what we wanted to do would cost in the neighborhood of $700! After pricing batteries, a charger for the batteries, and other related accessories needed, we were looking at $1200, and the plane would only fly for about 5 to 7 minutes on a charge.

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Then, we discovered Skycraft Parts and Surplus. We found a motor that would put out the power required for only $5.95 each! Yes, 6 dollars! The motor draws approximately 1 amp no load @ 12VDC. RPM 13,700 @ 12 VDC, 11,000 @ 9 VDC, 7,000 @ 6 VDC. We bought 4 of them. Now, what battery? Enter: PlanetBattery.Com. We bought 2 batteries for $20 each and a charger for $40. After testing with a 19" propeller, we found that hooked up in series at 12 volts, these 6v batteries would give us all the flight time we needed. So much so that we put a switch on the control handle for turning the motor on and off.

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The model is covered with 100% cotton muslin fabric, sold at Hancock's. We used Shelac as a substitute for the far more expensive airplane dope. Tite-Bond (yellow) glue turned out to be a fairly good choice for sticking it together.

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Insignia from the web, and enhanced in PhotoShop, then printed, and laminated onto the skin of the model with thinned glue. Aircraft total weight is 25 pounds.

The paint is: Manor Hall Exterior Latex from the Monarch Paint Company, as suggested by the paint contractor here in our new subdivision. We mixed custom colors with Testors Model Enamels, then made paint chips and sent them down to Monarch, where they again mixed custom colors. Never used better paint.

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What are we going to do with it? WE'RE GOING TO FLY IT!.

NEXT?: (92" wingspan...)

VOUGHT F4U-4 CORSAIR

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E-mail: bparker@parkerinfo.com
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