Seversky P-35 (oz5937)

About this Plan

Seversky P-35. RC scale model for 1.5 to 2.5 engines. This 1/5 scale model is covered with 0.005 thick aluminium sheet.

Quote: "A true scale model of a unique fighter produced prior to WWII. By Col Art Johnson, Master Modeler.

A US fighter plane without a popular name? Yes, the P-26 Peashooter came before it and the P-36 Hawk and P-40 Warhawk after. Its immediate factory descendent was the P-43 Lancer but the Seversky P-35 was known only as the P-35. Although it didn't have a catchy name. the P-35 was a very historical aircraft and the Granddaddy of the P-47 Thunderbolt.

Seversky's fighter went into operational service in 1937 with the three fighter squadrons stationed at Selfridge Field, Michigan. The squadrons were equipped with the total buy of the P-35 (76 aircraft). This was a year before the Hawker Hurricane Mk1 was operational in England, and the Hurricane at that time had a lot of fabric covering and a wooden two blade prop. The Seversky P-35 was, in fact, the first USAAC fighter to have an enclosed cockpit, metal covering without wire bracing, and three retractable wheels. It was the first of our modern low wing fighters and operational at a time when the US Navy was still ordering biplanes.

An early model of the Pratt & Whitney twin row Wasp R-1830 engine powered the P-35. The original 850 hp pushed the plane at a top speed of 280 mph. Later models of this engine hit 1150 hp in the P-36. 1250 hp in the P-43 and F4F Navy Wildcat, and more than that in the B-24 bombers. Civilian versions of the Seversky P-35 won the Bendix Trophy Race two years in a row 1938, 1939). Jackie Cochran set numerous speed records with the plane and Jimmy Doolittle flew one for Shell Oil. These civilian versions of the plane give modelers a different choice of paint scheme including gold, green, and yellow. The military versions came out of the factory in shiny aluminum.

Foreign countries liked the Seversky fighter so well that they ordered more than this country. The Japanese bought 20 and others went to South American Countries. The biggest order was from Sweden and half of the planes (60) EPI-106 aircraft from this order became P-35A's when they were held back by the US and sent to bolster the defenses of the Philippines in 1940. These P-35's saw combat against the Japanese in December 1941, but for a very short time. Most were knocked out on the ground as were the other USAAF aircraft based at Nichols and Clark. The P-35's were still in their bright silver finish when the Japanese attacked and they said that they could see them from 50 miles out.

If the P-35 was so famous. how come we have not seen any R/C models of the type until now? I was asking myself that question when a friend of mine, Dr Kitson, first interested me in building a model of the plane. Bob Kitson remembered the P-35 from his early days in Michigan and had collected 3-views and other documentation over the years. When he learned that I might try an R/C version. he loaned me the whole package and the project just grew from there.

I decided that maybe scale modelers had not tried the P-35 because it had a short nose and tail moment, narrow gear, and a lot of projecting parts that would have to be familiar with the details. Closer to my home is a P-35A that was restored by the USAF Museum and is now in the Weeks Air Museum in Miami, Florida. These are the only remaining P-35's and both look like they just came out of the factory complete with buffed aluminum finish.

There are a number of 3-views of the P-35 with the most detailed being Wylam's drawings. These drawings are loaded with dimensions - supposedly of the original. When I put these dimensions in a computer CAD program and tried to reproduce the bulkhead drawings. it was apparent that something was wrong. If I had built a model with these bulkhead sections. it would have turned out very strange indeed. The drawings by Paul Man turned out to be better and the Williams Brothers improved on these.

For my own drawings, thanks to cooperation from the people at the Weeks Museum. I was able to actually measure all the details of the aircraft and put the correct dimensions into my own computer drawings. It sure helps to know the exact width of the wheel fairings, the length of the scoops, and many other similar details. For this reason I used the markings and details of the P-35A in the Weeks Museum for my own model. It is painted like the 17th Pursuit Squadron P-35A of the Squadron Commander as used in 1941 in the Philippines. If you build the version of the P-35 in the USAF Museum, you would not have to make the gun blisters or the extension to the carburetor scoop that was added as a modification to the P-35A as it appears in the Weeks Museum.

Construction. Scratch-building a scale model from plans is not a task for beginners, so we are going to assume that anyone attempting this model has some scale building experience under their belt. Some building techniques on this model were a bit different, however, and some tips on these might be of interest.

As usual, I like to get the tedious part of building out of the way first - meaning the wings. Besides, it is easier to fit the fuselage to the wing than the other way.

Wing: Seversky came up with his own airfoil for the P-35. He called it a CYH - I am only guessing if I call this a Clark Y Hybrid. It does have a flat bottom over much of the chord but with a fairly sharp leading edge and a definite reflex at the trailing edge. l used the scale airfoil because past experience has shown me that most models will fly decently with the same airfoil as the original. This was going to be a built-up balsa wing because cutting an elliptical wing from foam looked like too sticky a project. No two ribs on the wing have the same thickness percentage due to the elliptical shape. Generating rib drawings of this type on the computer is pretty straightforward - by hand it's another story.

The position of the main spar is dictated by the need to retract the wheels partially into the wing. The ply spar running past the gear mounts provides the strength needed for not so nice landings..."

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