As soon as the airplane joined motorized ground vehicles as tools of war, its ability to see over the horizon made it an invaluable tactical device. It was more mobile than a tethered balloon and could be used to transport messages and leaders from point to point, whenever and wherever it was needed. There was one disadvantage, however: An airplane needed a relatively flat, longish piece of ground from which to take off and land. Then Germany’s newly formed Luftwaffe brought the Fiesler Fi 156 Storch to the 1938 Cleveland Air Races. It was seen as the vehicle of long-distance adventurers and airline pioneers.
American military planners observing the races saw a clear definition of the term “short takeoff and landing,” later known as “STOL.” The Storch could work out of a tennis court, and the U.S. government promptly put out a request for proposal to aircraft manufacturers to devise such a machine.
Three companies were selected to build prototypes of their proposed designs: Stinson (O-49), Bellanca (YO-50), and Ryan (YO-51 Dragonfly). The O-49, known within the company as the “Model 74” and later named the “Vigilant,” was the winner. Incidentally, the Army changed the “O” for “Observation” to “L” for “Liaison” in 1942, and the O-49 was the first to wear the new designation as the L-1. (For even more confusion, shortly after the plane entered production in 1941, Stinson was absorbed into Vultee, which became Consolidated-Vultee.)
The L-1 was a study in specialty engineering, both structurally and aerodynamically, and was a relatively complex airplane. Everything in it was aimed at producing an aircraft that needed very little forward speed to fly. Besides having huge wings (50 feet, compared to a Mustang’s 37), its flaps were gigantic and went down 43 degrees, with the ailerons drooping 20 degrees at the same time. As if that weren’t enough to generate more lift, the movable Handley-Page leading edge slats would slide out automatically, letting the wing fly at higher-than-normal angles of attack. Of course, getting 300hp out of the Lycoming R-680-13 in the nose helped.
Pat Harker of C & P Aviation, in Anoka, Minnesota, restored and owns the Oshkosh award-winning L-1 pictured here—one of only three still flying. “I have yet to get it to actually stall,” he says. “The slats start to slowly drift out automatically around 55mph, and it’ll get down to around 22mph with the controls still feeling totally normal. However, you’re still not in a nose-high attitude. You can bring it down over the runway with practically no ground speed, chop the power, plop it on, get on the brakes, and you roll almost no distance at all. It’s amazing. And it’s huge fun!”
Only 324 Vigilants were built, before being replaced on the Stinson production line by the firm’s own L-5 Sentinel (3,896 built). Most surviving L-1s migrated to Alaska, where they were worked to death, but their bones lasted long enough to be collected and rehabilitated by the likes of Pat Harker and Fantasy of Flight’s Kermit Weeks.
by Budd Davisson | Photos by David Leininger
Dear Mr. Davisson,
It is a popular but fictional notion that the demonstration of the Fieseler Fi-56 Storch at the Cleveland Air Races in September 1938 prompted the Air Corps to solicit proposals for a similar aircraft from American manufactures. U.S. military interest in the Storch actually began more than a year prior to the air races. Here are the facts as I know them,. Hopefully you and your readers will find it interesting and enlightening:
 The Storch was demonstrated at the International Aviation Meet in Zurich during the first week of August, 1937. Several U.S. naval intelligence observers were present, as well as the military attache to France and a representative of the National Advisory Committee on Aeronautics [NACA].
 The Office of Naval Intelligence submitted a thorough report on the Fi-156 on August 10th and it was quickly circulated through channels. The ONI circulated a second report six weeks later, outlining the use of the Storch during German infantery maneuvers at Stavenhagen, noting it’s usefulness for tactical scouting.
 During a visit to Germany, Charles Lindbergh test flew the Storch on October 16th and 17th of 1937. This was reported in the newspapers two days later by which time Lindy had passed his evaluation on to the American military attache in Berlin.
 On 4th November 1937, the Materiel Division at Wright Field reported to the Chief of the Air Corps [Arnold] that they were “confident that it would be possible to develop such an airplane as the Storch along more conventional lines, using accepted and proved principles.” The same day, the Adjutant General queried Arnold, asking his opinion whether a “low speed airplane” should be included in Air Corps R&D program, and if so, he should should put the recommendation before the Secretary of War for approval.
 After studying the matter, on December 21st, it was determined that $100,000 in funds could be diverted from another project and a formal design competetion was recommended. Two days later, the proposal was approved by the Adjutant General.
 On january 8th, 1938 the Engineering Section at Wright Field sent its feasibility study through channels and on January 11th, the Secretary of War approved it.
 After six months of determinin specific characteristics for the airplane and evaluating other options, on August 23, 1938 Circular Proposal 39-2 inviting proposals for short a range liaison airplane was realeased. That was 15 days before the Storch “stole the show” at the Cleveland Air Races.
So that’s the real background story about how Stinson’s remarkable Vigilant came about. The Cleveland Air Races simply served to alert those “outside the loop” that Germany had a remarkable airplane and that we ought to match it. Little did they know that it was already well undser way.
I have a very thick file containing of all the Wright Field historical documents about the Fi-56 anbd O-49 right here on my desk should you or anyone else be interested in learning more of the story.
Jim Gray, Juneau Alaska,
Historian and researcher. Founder of the Sentinel Owners & Pilots Association.
Another correction: The 3.896 L-5’s built quoted by Mr. Davisson comes from somewhere very far out in left field. 4,375 Stinson L-5’s were contracted but Stinson only delivered 3,590 of them to the military and the remaining 875 were cancelled. 43 others that were in various stages of assembly when WWII ended were completed and sold on the civilian market in 1946, making a total of 3,633 built altogether. These are the correct numbers backed up by ample primary-source documentation.
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