What was the first Control Line Plane with the motor upside down?
There are probably several candidates for this. Exact dates of when first built are somewhat uncertain for the following.
The first Big Job was built by Addie Naccarato, it had an inverted engine. Really ahead of its time with a big wing, thick airfoil, long tail moment with a good sized horizontal tail. There is a picture of it in the 1953 Air Trails Annual that says it is from 1951. When researching this airplane, Tony, her son, told Charlie Reeves for the April 2007 construction article Flying Models that the original was built in 1948. (In my opinion, one of the four top old time stunt designs.)
Another candidate is an interesting one. The Pagan was published in the 1951 Aeromodeller Annual. Another one ahead of its time. Inverted engine. A semiscale design of the deHavilland TK-4 racer. Really quite a good looking airplane. A really good performing OTS design.
Another semi scale design and a good performer for OTS is the Black Tiger by Robert Elliott. Published in the February 1953 issue of Air Trails. The article said construction was started in 1951. A great article on this design was published in the July 1996 issue of Flying Models.
The Bouncing Bertie was published in the June 1952 issue of Air Trails. This was a triplane, inverted engine. No mention in the article when it was first designed.
Can-Stunt was a pusher canard with an inverted engine. Published in an early issue Flying Models. I am checking for a publish date.
The Stunt Champ by Lloyd Curtis won the 1952 Plymouth Internats in his age category. Published in the March 1953 issue of Air Trails. No mention of when it first flew of designed.
From Air Trails, October 1950, there was a design by S. Calhoun Smith (old timers know about him) that was a semi scale of the Delanne double mono-plane. Had an inverted engine. Interesting design.
December, 1948 Model Airplane News had the stunt model called the Screwball Fury by J. S. Luck. Inverted engine. This is a very attractive design that others have said is a capable OTS design. Perhaps another model, with little attention that was well before its time. It is in the Morris OTS book.
Lethal Lucy by Leon Shulman, Air Trails, December 1952 had an inverted engine. Surprised we have not seen more of these in OTS.
The Moitle, a biplane, has already been mentioned. This design, resurrected by Don Hutchinson in the 90's was first designed in 1946. Had an inverted engine. Documented by Don with its designer, Francis Reynolds, officially recognized by PAMPA as OTS legal. Plans in June 1996 Model Builder.
Don Still's Stuka Stunt was designed in the 1951 time frame, published in April 1952 Air trails. Inverted engine.
Almost all of the designs mentioned above are what could be considered OTS airplanes.
There might have been some scale designs from before 1950 that featured inverted engines.
One of the earliest published designs for control line with an inverted engine is from December 1943 model Airplane News. This was a very attractive gull-wing model that gives the appearance of the fighters or more correctly the military observation aircraft from the mid 1930's. 46 inch span, 350 sq in. Even shows the details for what would be considered now as a typical bellcrank, unusual for the time. Semi-symmetrical wing section, about 14% section. Just called the "Control Line Fighter" by Peter Westburg who is/was responsible for many detailed scale drawings published many years later, primarily in Model Builder magazine. Very detailed plans and very detailed construction article. Nothing is mentioned about maneuverability, but basic maneuvers should be possible, particularly if built light enough.
Interesting question.
Keith