Stinson’s Big-Guy L-Bird: L-1 Vig­i­lant

Flight Journal - - CONTENTS - by Budd Davis­son

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 (YO50), 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-thannor­mal 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.

Above: Ac­cord­ing to Pat Harker, the owner/re­storer/ pi­lot, the cen­ter­mounted gear “wad­dles” a lit­tle but ab­sorbs land­ing shocks with al­most no re­bound.

Left: Al­most un­no­tice­able in the bliz­zard of orig­i­nal de­tail and tub­ing are com­pli­cated pieces, such as the Y-shaped, com­pound-formed alu­minum cover over the rear con­trol ca­bles. The air­plane abounds in such com­plex­i­ties.

Above, right, and be­low: As part of the Air Trans­port Com­mand, the air­plane was mod­i­fied for many pur­poses: in the air, on the ground, and in the wa­ter. It was to be “util­ity” per­son­i­fied. (Pho­tos cour­tesy of Stan Piet)

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