| © James H. Gray |
Sentinel Owners and Pilots Association
| I...Introduction |
The Stinson L-5 is one of the most important but overlooked American airplanes of World War Two.
Overshadowed by the more glamorous fighters and bombers, and outnumbered by the popular Piper L-4
Cub, the Sentinel has been relegated to relative obscurity. Nearly 4,000 were built in Wayne, Michigan, by
the Stinson Division of the Consolidated-Vultee Corporation between 1942 and 1945 but only a few
hundred have survived.
Overshadowed by the more glamorous fighters and bombers, and outnumbered by the popular Piper L-4
Cub, the Sentinel has been relegated to relative obscurity. Nearly 4,000 were built in Wayne, Michigan, by
the Stinson Division of the Consolidated-Vultee Corporation between 1942 and 1945 but only a few
hundred have survived.
| .Stinson L-5B owned by Brad Hurley, Croydon Hills, Australia |
.The most versatile and robust of the Army's "grasshopper" fleet of liaison aircraft, the L-5 was a true
workhorse and flew a wider variety of missions than any other type. Designed especially with combat support
in mind the L-5 didn't require an airfield to operate and could be maintained under the most primitive of
conditions. Routinely called on for artillery spotting, photo reconnaissance, re-supply, search and rescue,
evacuating the sick or wounded, dispatching couriers, and transporting personnel, the Sentinel performed
missions that are now mostly accomplished by helicopters.
workhorse and flew a wider variety of missions than any other type. Designed especially with combat support
in mind the L-5 didn't require an airfield to operate and could be maintained under the most primitive of
conditions. Routinely called on for artillery spotting, photo reconnaissance, re-supply, search and rescue,
evacuating the sick or wounded, dispatching couriers, and transporting personnel, the Sentinel performed
missions that are now mostly accomplished by helicopters.
Never far from the action, the sturdy Stinsons participated in most theaters of the war and became a familiar
sight to friendly and enemy troops alike. American soldiers commonly used the nickname "Flying Jeep" when
referring to the L-5 because it was rugged, versatile, and could be relied upon to accomplish nearly anything
asked of it. British troops fighting in Burma also greatly admired the Sentinel and christened it the "Jungle
Angel" for bringing life-saving ammunition, food, medecine, replacements and mail to areas not accessible to
other aircraft. Thousands of people in all theaters owed their lives and welfare to the courageous men who
flew these unarmed and unarmored machines.
sight to friendly and enemy troops alike. American soldiers commonly used the nickname "Flying Jeep" when
referring to the L-5 because it was rugged, versatile, and could be relied upon to accomplish nearly anything
asked of it. British troops fighting in Burma also greatly admired the Sentinel and christened it the "Jungle
Angel" for bringing life-saving ammunition, food, medecine, replacements and mail to areas not accessible to
other aircraft. Thousands of people in all theaters owed their lives and welfare to the courageous men who
flew these unarmed and unarmored machines.
A Civilian Origin
The L-5 Sentinel had a civilian origin and was roughly based on the Stinson Model 105 Voyager. Unlike
other pre-war civilian aircraft that were adopted pretty much off-the-shelf by the military, the Voyager
underwent a substantial redesign and emerged as a new type specifically tailored for the liaison role.
other pre-war civilian aircraft that were adopted pretty much off-the-shelf by the military, the Voyager
underwent a substantial redesign and emerged as a new type specifically tailored for the liaison role.
| ..1939 Model 105 Voyager. |
(Aerofiles photo)
The Model 105 Voyager was first introduced in 1939 as the HW-75. This was an engineering designation
that indicated it had a high wing and a 75hp engine. The entire airframe was fabric covered and featured a
welded steel-tube fuselage, predominantly wooden wings and tail, and a steerable tailwheel. Surprisingly,
the wings incorporated the advanced concepts of slotted flaps and leading edge slots to enhance lowspeed
flight and handling characteristics. An 80 horsepower version, called the HW-80, was also offered.
that indicated it had a high wing and a 75hp engine. The entire airframe was fabric covered and featured a
welded steel-tube fuselage, predominantly wooden wings and tail, and a steerable tailwheel. Surprisingly,
the wings incorporated the advanced concepts of slotted flaps and leading edge slots to enhance lowspeed
flight and handling characteristics. An 80 horsepower version, called the HW-80, was also offered.
.The 105 Voyager name came about as a marketing scheme in order to boost orders. Sales literature
emphasized the comfort, styling, and 105 mph cruise speed while hinting at unlimited freedom and
adventure. Specifically aimed at the growing personal use market, the Voyager proved quite successful and
over 500 were sold. It had side-by-side seating and a third "jumpseat" in back where a passenger could
ride sitting crosswise. In reality three occupants was not very practical unless the rear passenger was a
child, but the extra space easily accomodated more baggage than competing 2-place designs.
emphasized the comfort, styling, and 105 mph cruise speed while hinting at unlimited freedom and
adventure. Specifically aimed at the growing personal use market, the Voyager proved quite successful and
over 500 were sold. It had side-by-side seating and a third "jumpseat" in back where a passenger could
ride sitting crosswise. In reality three occupants was not very practical unless the rear passenger was a
child, but the extra space easily accomodated more baggage than competing 2-place designs.
.Further refined in 1940, the Voyager was marketed in two versions: the spartan 75hp Model 10A (HW-75)
and the luxuriously appointed 90hp Model 10B (HW-90). The fuselage was widened somewhat on both
models and many other small improvements were made. These versions were even more popular than the
original Model 105 and over 750 were produced. Voyagers were owned by notables such as Howard
Hughs, Roscoe Turner, Jimmy Stewart, Wilbur Shaw, and Edgar Bergen and these celebrities undoubtedly
helped improved sales . Eventually, the design also caught the eye of the U.S. Army.
and the luxuriously appointed 90hp Model 10B (HW-90). The fuselage was widened somewhat on both
models and many other small improvements were made. These versions were even more popular than the
original Model 105 and over 750 were produced. Voyagers were owned by notables such as Howard
Hughs, Roscoe Turner, Jimmy Stewart, Wilbur Shaw, and Edgar Bergen and these celebrities undoubtedly
helped improved sales . Eventually, the design also caught the eye of the U.S. Army.
| A Stinson Model 10A in standard two-tone finish |
(photo obtained from L. Westin)
The Army Takes an Interest
In 1938, the Germans brought their Fiesler FI-156 'Storch' to the U.S. for a public demonstration. The
very-impressed onlookers included U.S. Army personnel and representatives from several aircraft
manufacturers. Major General 'Hap' Arnold, by then appointed Chief of the Army Air Corps, recognized the
possibilities of such an aircraft, so in 1940 the Army invited various manufacturers, including Stinson, to
submit existing designs for field trials in order to assess the military potential of civilian aircraft. Among the
planes tested were six Voyagers specially fitted with 100hp Franklin O-200-1 engines. These peppy little
airplanes were designated YO-54's , the 'Y' meaning "evaluation status" and the 'O' meaning "observation"
category. They performed and handled well enough that the Army ordered ten additional ones. They initially
labelled the type AT-19A but the designation was ultimately changed to L-9A in 1942. Primarily used for
training and coastal patrol work by the Civil Air Patrol and Civilian Pilot Training Program, this tiny fleet was
eventually augmented by sixteen 90hp civilian models that were designated L-9B's.
very-impressed onlookers included U.S. Army personnel and representatives from several aircraft
manufacturers. Major General 'Hap' Arnold, by then appointed Chief of the Army Air Corps, recognized the
possibilities of such an aircraft, so in 1940 the Army invited various manufacturers, including Stinson, to
submit existing designs for field trials in order to assess the military potential of civilian aircraft. Among the
planes tested were six Voyagers specially fitted with 100hp Franklin O-200-1 engines. These peppy little
airplanes were designated YO-54's , the 'Y' meaning "evaluation status" and the 'O' meaning "observation"
category. They performed and handled well enough that the Army ordered ten additional ones. They initially
labelled the type AT-19A but the designation was ultimately changed to L-9A in 1942. Primarily used for
training and coastal patrol work by the Civil Air Patrol and Civilian Pilot Training Program, this tiny fleet was
eventually augmented by sixteen 90hp civilian models that were designated L-9B's.
| .1941 YO-54 |
(AeroFiles photo)
A Winning Design
The YO-54, with its fixed leading-edge slats, had great handling qualities but lacked the power and many
other features that the Army most desired. They really wanted an aircraft comparable to the impressive
Fieseler Storch didn't didn't want to spend a lot of money or wait years for development of a new type.
Many good designs were already around that could match the Fiesler, including the Vultee (Stinson) L-1 /
O-49, but all were found wanting because they either required too many strategic materials in their
construction, had high maintainance requirements, were too complicated for rapid production, or simply cost
too much money.
other features that the Army most desired. They really wanted an aircraft comparable to the impressive
Fieseler Storch didn't didn't want to spend a lot of money or wait years for development of a new type.
Many good designs were already around that could match the Fiesler, including the Vultee (Stinson) L-1 /
O-49, but all were found wanting because they either required too many strategic materials in their
construction, had high maintainance requirements, were too complicated for rapid production, or simply cost
too much money.
| ..Fiesler Fi-156 "Storch" |
(Gallery of Flight)....
In the end, the excellent aerodynamic qualities and relatively simple maintainance and construction of the
Voyager won out, but not before it underwent a major redesign. Although a large number of components
were retained , the upgraded version was substantially different from its parent in both appearance and
structure. The slotted wing was substantially stiffened to endure greater aerodynamic stress, a new lengthened
fuselage featuring tandem seating and 'greenhouse' windows increased visibility all around. Long-stroke main
gear oleos and a telescoping oleo-damped tailwheel strut greatly improved its rough-field capability. The fin
and rudder were also enlarged and the number of aluminum components throughout the airframe were
substantially reduced. Many other changes (too numerous to mention here) were also incorporated. Most
importantly, all these alterations required only a small change in factory tooling and assembly procedures so
that production could commence almost immediately.
Voyager won out, but not before it underwent a major redesign. Although a large number of components
were retained , the upgraded version was substantially different from its parent in both appearance and
structure. The slotted wing was substantially stiffened to endure greater aerodynamic stress, a new lengthened
fuselage featuring tandem seating and 'greenhouse' windows increased visibility all around. Long-stroke main
gear oleos and a telescoping oleo-damped tailwheel strut greatly improved its rough-field capability. The fin
and rudder were also enlarged and the number of aluminum components throughout the airframe were
substantially reduced. Many other changes (too numerous to mention here) were also incorporated. Most
importantly, all these alterations required only a small change in factory tooling and assembly procedures so
that production could commence almost immediately.
| ...L-5B owned by John Markham, Subiaco, W.A. |
(photo courtesy of John Markham).....
.Known conceptually as the Model 75, the ptototype was tested with various engine configurations before
the 185 horsepower six-cylinder Lycoming O-435-1 was finally selected. The features and performance of
the final version, known as the Model 76, so completely impressed the Army that a contract for 275
airplanes was immediately awarded and the normally required evaluation period was waived. The Stinson
Model 76 was originally given the designation O-62 but this was changed to L-5 by the time the first
airplanes were delivered.
the 185 horsepower six-cylinder Lycoming O-435-1 was finally selected. The features and performance of
the final version, known as the Model 76, so completely impressed the Army that a contract for 275
airplanes was immediately awarded and the normally required evaluation period was waived. The Stinson
Model 76 was originally given the designation O-62 but this was changed to L-5 by the time the first
airplanes were delivered.
Congress ultimately allocated money for several additional batches of Sentinels.Seventeen hundred were
requisitioned in 1942, and twenty-four hundred were ordered in 1944. By 1945, improvements to the design
resulted in four other production designations: the L-5B, L-5C, L-5E, and L-5G . Navy and Marine versions
were identical to the Army models but were known as the OY-1 and OY-2, while British Lend-Lease
airplanes were known as the Sentinel I and Sentinel II
requisitioned in 1942, and twenty-four hundred were ordered in 1944. By 1945, improvements to the design
resulted in four other production designations: the L-5B, L-5C, L-5E, and L-5G . Navy and Marine versions
were identical to the Army models but were known as the OY-1 and OY-2, while British Lend-Lease
airplanes were known as the Sentinel I and Sentinel II
Official U.S. Navy Phot
Post War Use
After WWII many L-5's went to Korea and remained operational until replaced by the all-metal Cessna
L-19 "Bird Dog". Other's served training and utility functions in Japan, Europe or the U.S. until the
mid-1950's, and some even went to foreign Air Forces. A few survived in the U.S. armed services into the
1960's, but most Sentinels were removed from active duty by 1957. Large numbers were distributed to Civil
Air Patrol squadrons where they continued to be useful for training or search-and-rescue missions up to
about 1970. One notable Sentinel remained in the Air Force inventory for many years (re-designated U-19B)
and was used at the Air Force Academy as a glider tug.
L-19 "Bird Dog". Other's served training and utility functions in Japan, Europe or the U.S. until the
mid-1950's, and some even went to foreign Air Forces. A few survived in the U.S. armed services into the
1960's, but most Sentinels were removed from active duty by 1957. Large numbers were distributed to Civil
Air Patrol squadrons where they continued to be useful for training or search-and-rescue missions up to
about 1970. One notable Sentinel remained in the Air Force inventory for many years (re-designated U-19B)
and was used at the Air Force Academy as a glider tug.
| .Cessna L-19 Bird Dog |
(photo obtained from IBDA)
.Hundreds of surplus L-5's found their way into civilian hands and served many tasks including training, crop
spraying, banner towing, aerial photography, patrolling, and surveying. Popular among warbird enthusiasts,
quite a few Sentinels have been restored to military configuration and can be seen at fly-ins and airshows.
About two dozen examples have been preserved in aviation museums around the United States, and several
others can be seen abroad. (See the "Preserved Aircraft" page for details)
spraying, banner towing, aerial photography, patrolling, and surveying. Popular among warbird enthusiasts,
quite a few Sentinels have been restored to military configuration and can be seen at fly-ins and airshows.
About two dozen examples have been preserved in aviation museums around the United States, and several
others can be seen abroad. (See the "Preserved Aircraft" page for details)
| OY-1 owned by Dick Blosser, Fullerton, CA |
(photo courtesy D. Blosser)
| Welcome to the Stinson L-5 Data Pages A brief history of the L-5 design |
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