L-5 Sentinel
Encyclopedia
The Stinson L-5 Sentinel was a World War II era liaison aircraft used by all branches of the U.S. military and by the British Royal Air Force. Along with the Stinson L-1 Vigilant, the L-5 was the only other American liaison aircraft of WWII that was purpose-built for military use and had no civilian counterpart. All other military liaison airplanes adopted during World War II were lightly modified "off-the-shelf" civilian models.
The origins of the L-5, affectionately known as the "Flying Jeep", can be traced to the pre-war civilian Stinson HW-75. The 75 horsepower high-wing design, built by the Stinson Aircraft Company at Wayne, Michigan, first flew in 1939 and became an immensely popular civilian airplane. It featured two front seats side-by-side, and a third "jumpseat" in back in which a small passenger could sit sideways. The design was very easy to fly, luxurious compared to contemporary personal light airplanes, and it was difficult to stall and virtually impossible to spin. Shortly after the introduction of the HW-75, Stinson became a subsidiary of the Vultee Aircraft corporation. Under Vultee management, Stinson equipped the HW-75 with an 80-horsepower four-cylinder engine for the 1940 model year, the HW-75 became known as the Model 105 "Voyager", touting its 105 mph cruise speed and comfortable cross-country capability. Re-equipped with a four-cylinder 90 hp Franklin engine for the 1941 model year, the type became known as the Model 10A. In the post-war era, the fuselage of the Model 10A was slightly lengthened and widened to accommodate four seats, and the four-cylinder powerplant was replaced with a Franklin 150 hp six-cylinder engine. This conversion became the widely known Stinson Model 108 Voyager and the only civilian airplane commercially produced by Stinson after WWII.
Six examples of the pre-war Model 105 Voyager were specially equipped with 100 horsepower Franklin O-200 engines and presented to the military for testing under the experimental designation YO-54. Evaluated by the U.S. Army and Air Forces in 1940 for potential use as a low-cost short range observation aircraft, it failed to meet military performance requirements, despite out-performing all other civilian contenders in the military competition. The Voyager was then completely re-engineered by Stinson into a much stronger and more powerful tandem-seat airplane that met all the Army engineering handbook standards for the design of military aircraft. The prototype, designated as the Model V-76 by Vultee / Stinson was accepted by the military after accelerated service trials and entered into service in December 1942 as the Army O-62 ('O' for observation). In March 1943, with the official establishment of the liaison category of light observation aircraft, the designation was changed to L-5. The primary purpose as a liaison airplane was courier and communication work with the Army Air Forces (USAAF)and artillery spotting with Army Ground Forces, but the rugged and highly capable little airplane soon took on an expanded role and eventually performed more jobs than almost any other airplane in the combined services. The later models were redesigned with a wider and deeper rear fuselage section and a cavernous rear door that easily allowed a litter patient to be quickly loaded. These L-5B and later variants were employed for front-line air ambulance and cargo work.
The L-5 series was manufactured between December 1942 and September 1945, during which time 3,590 of these unarmed two-seaters were built for the United States
armed forces, making it the second most widely used light observation aircraft of the war behind the Piper L-4 Cub. Personnel in all service branches commonly referred to the L-5 as the "Flying Jeep". The fuselage was constructed using chrome-moly steel tubing covered with doped cotton fabric and the wings and empennage were constructed of spruce spars and plywood ribs and skins, also covered with fabric. The use of aluminum, which was in critically short supply and more urgently needed for other aircraft, was limited to the engine cowling, tail cone, framework for the ailerons, rudder and elevator and the landing gear fairings. The plane was powered by a six-cylinder Lycoming O-435 engine of 190 horsepower that was specifically designed and manufactured for use on the L-5.
, the L-5 "Sentinel" delivered personnel, critical intelligence and needed supplies to the front line troops. On return flights, wounded soldiers were often evacuated to rear area field hospitals for medical treatment, providing a huge boost to the morale of combat troops fighting in remote areas. L-5's were used for many other important activities, such as aerial photography, controlling vehicle convoys, para-dropping food, medical supplies and ammunition, laying communication wire, distributing propaganda leaflets, spraying pesticide, transporting prisoners, and directing fighter-bombers to ground targets. The L-5 was also popular with Generals and other high-ranking officers for fast, efficient short-range transportation.
Five versions of the Sentinel were produced for the U.S. Army Air Force (USAAF); the L-5, L-5B, L-5C, L-5E and L-5G. There was no official L-5A variant as is often reported because the designation was intended for a version of the aircraft that was never built. Nonetheless, many people in and out of the military still refer to the standard "observer" version of the L-5 as an L-5A. Like the L-5A, the L-5D was a planned version that was not adopted. A single L-5F was an L-5B equipped with an experimental low-noise "stealth" propeller and exhaust system for research purposes. An L-5H version was on the drawing boards at Stinson when the war ended, and it never reached the prototype stage.
The L-5 carried a pilot
and observer in a tandem seating configuration, which was preferred by the military for observation work. The L-5B through L-5G models were modified to carry a litter patient or light cargo, or a rear seat passenger sitting in the normal position. The Navy and Marine version of the L-5 through L-5E were designated 0Y-1, and all these airplanes has 12-volt electrical systems. The 24-volt L-5G became the0Y-2. Neither the L-5G nor OY-2 saw combat during WWII because production did not begin until July, 1945, just weeks before the war ended, but they were used extensively during the Korean War. The British RAF procured 40 L-5's and 60 L-5B's, and designated them Sentinel I's and Sentinel II's respectively. These airplanes were used exclusively in the India-Burma theater of operations.
O-62
L-5
L-5A
L-5B
L-5C
L-5D: Not adopted. No prototype built.
L-5E
L-5G
XL-5
U-19A
U-19B
0Y-1
0Y-2
Sentinel Mk I
Sentinel Mk II
during the Korean War
. The Royal Air Force operated 100 Sentinels in India and Burma.
After WWII, the Philippine Army Air Corps
used this aircraft from 1945 to 1947. This aircraft remained in service after 1 July 1947 when the PAAC was renamed the Philippine Air Force
. The Italian Air Force operated approximately 100 L-5's from 1946 into the 1950s. Many other countries also received L-5's after the war, particularly India which received 200. A number of these went to Pakistan after the partition of India in 1948.
, the L-5 was widely used by the Civil Air Patrol
for search and rescue work. Today there are about 300 known examples left world wide and less than half are in flying condition. A restored, flying example of the 0Y-1 (L-5E) variant (VH-NOY) is located in Coolangatta, Queensland
, Australia
. This example was built for the USAAF but was delivered directly to the US Navy
instead, serving until 1949. A group called the Sentinel Owners and Pilots Association is dedicated to the preservation and enjoyment of this aircraft type.
The origins of the L-5, affectionately known as the "Flying Jeep", can be traced to the pre-war civilian Stinson HW-75. The 75 horsepower high-wing design, built by the Stinson Aircraft Company at Wayne, Michigan, first flew in 1939 and became an immensely popular civilian airplane. It featured two front seats side-by-side, and a third "jumpseat" in back in which a small passenger could sit sideways. The design was very easy to fly, luxurious compared to contemporary personal light airplanes, and it was difficult to stall and virtually impossible to spin. Shortly after the introduction of the HW-75, Stinson became a subsidiary of the Vultee Aircraft corporation. Under Vultee management, Stinson equipped the HW-75 with an 80-horsepower four-cylinder engine for the 1940 model year, the HW-75 became known as the Model 105 "Voyager", touting its 105 mph cruise speed and comfortable cross-country capability. Re-equipped with a four-cylinder 90 hp Franklin engine for the 1941 model year, the type became known as the Model 10A. In the post-war era, the fuselage of the Model 10A was slightly lengthened and widened to accommodate four seats, and the four-cylinder powerplant was replaced with a Franklin 150 hp six-cylinder engine. This conversion became the widely known Stinson Model 108 Voyager and the only civilian airplane commercially produced by Stinson after WWII.
Six examples of the pre-war Model 105 Voyager were specially equipped with 100 horsepower Franklin O-200 engines and presented to the military for testing under the experimental designation YO-54. Evaluated by the U.S. Army and Air Forces in 1940 for potential use as a low-cost short range observation aircraft, it failed to meet military performance requirements, despite out-performing all other civilian contenders in the military competition. The Voyager was then completely re-engineered by Stinson into a much stronger and more powerful tandem-seat airplane that met all the Army engineering handbook standards for the design of military aircraft. The prototype, designated as the Model V-76 by Vultee / Stinson was accepted by the military after accelerated service trials and entered into service in December 1942 as the Army O-62 ('O' for observation). In March 1943, with the official establishment of the liaison category of light observation aircraft, the designation was changed to L-5. The primary purpose as a liaison airplane was courier and communication work with the Army Air Forces (USAAF)and artillery spotting with Army Ground Forces, but the rugged and highly capable little airplane soon took on an expanded role and eventually performed more jobs than almost any other airplane in the combined services. The later models were redesigned with a wider and deeper rear fuselage section and a cavernous rear door that easily allowed a litter patient to be quickly loaded. These L-5B and later variants were employed for front-line air ambulance and cargo work.
The L-5 series was manufactured between December 1942 and September 1945, during which time 3,590 of these unarmed two-seaters were built for the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
armed forces, making it the second most widely used light observation aircraft of the war behind the Piper L-4 Cub. Personnel in all service branches commonly referred to the L-5 as the "Flying Jeep". The fuselage was constructed using chrome-moly steel tubing covered with doped cotton fabric and the wings and empennage were constructed of spruce spars and plywood ribs and skins, also covered with fabric. The use of aluminum, which was in critically short supply and more urgently needed for other aircraft, was limited to the engine cowling, tail cone, framework for the ailerons, rudder and elevator and the landing gear fairings. The plane was powered by a six-cylinder Lycoming O-435 engine of 190 horsepower that was specifically designed and manufactured for use on the L-5.
Operational history
Capable of operating from short unimproved airstripsRunway
According to ICAO a runway is a "defined rectangular area on a land aerodrome prepared for the landing and take-off of aircraft." Runways may be a man-made surface or a natural surface .- Orientation and dimensions :Runways are named by a number between 01 and 36, which is generally one tenth...
, the L-5 "Sentinel" delivered personnel, critical intelligence and needed supplies to the front line troops. On return flights, wounded soldiers were often evacuated to rear area field hospitals for medical treatment, providing a huge boost to the morale of combat troops fighting in remote areas. L-5's were used for many other important activities, such as aerial photography, controlling vehicle convoys, para-dropping food, medical supplies and ammunition, laying communication wire, distributing propaganda leaflets, spraying pesticide, transporting prisoners, and directing fighter-bombers to ground targets. The L-5 was also popular with Generals and other high-ranking officers for fast, efficient short-range transportation.
Variants
The L-5 carried a pilot
Aviator
An aviator is a person who flies an aircraft. The first recorded use of the term was in 1887, as a variation of 'aviation', from the Latin avis , coined in 1863 by G. de la Landelle in Aviation Ou Navigation Aérienne...
and observer in a tandem seating configuration, which was preferred by the military for observation work. The L-5B through L-5G models were modified to carry a litter patient or light cargo, or a rear seat passenger sitting in the normal position. The Navy and Marine version of the L-5 through L-5E were designated 0Y-1, and all these airplanes has 12-volt electrical systems. The 24-volt L-5G became the0Y-2. Neither the L-5G nor OY-2 saw combat during WWII because production did not begin until July, 1945, just weeks before the war ended, but they were used extensively during the Korean War. The British RAF procured 40 L-5's and 60 L-5B's, and designated them Sentinel I's and Sentinel II's respectively. These airplanes were used exclusively in the India-Burma theater of operations.
O-62
- Observation, artillery spotting and liaison aircraft, powered by a Lycoming 0-435-1 piston engine. 275 built.
L-5
- Observation, artillery spotting and liaison aircraft. 1,538 built, 79 transferred to USN/USMC as 0Y-1.
L-5A
- Cancelled conversions of L-5 with 24V electrical system and 200 hp ranger engine.
L-5B
- 729 aircraft with rear fuselage hatch to permit loading of a stretcher or cargo; twin-float capability. 60 transferred to RAF as Sentinel Mk II, 40 transferred to USN/USMC as 0Y-1.
L-5C
- 200 L5-B were equipped K-20 reconnaissance cameras.
L-5D: Not adopted. No prototype built.
L-5E
- 750 STOLSTOLSTOL is an acronym for short take-off and landing, a term used to describe aircraft with very short runway requirements.-Definitions:There is no one accepted definition of STOL and many different definitions have been used by different authorities and nations at various times and for a myriad of...
variants with larger tires and brakes and manually ailerons drooping ailerons allowing shorter takeoff and landing; 152 transferred to USN/USMC as OY-1. Thirty later converted to 24 volt electrical systems and re-designated 0Y-2.
L-5G
- L-5E airframe powered by 190-hp (142-kW) Lycoming 0-435-11 piston engines with improved cylinders and carburetor and fitted with controllable pitch propellerControllable pitch propellerA controllable pitch propeller or variable pitch propeller is a type of propeller with blades that can be rotated around their long axis to change their pitch...
s. 115 built, by end of the war and 785 others cancelled. Electrical system 24-volts. Final production model redesignated U-19B in 1962.
XL-5
- One test and evaluation aircraft, powered by a Lycoming 0-435-2 piston engine.
U-19A
- L-5 variants still in service redesignated U-19A by the USAF in 1962.
U-19B
- One L-5E used as a glider tug at the United States Air Force AcademyUnited States Air Force AcademyThe United States Air Force Academy is an accredited college for the undergraduate education of officer candidates for the United States Air Force. Its campus is located immediately north of Colorado Springs in El Paso County, Colorado, United States...
in 1962.
0Y-1
- 306 L-5 and L-5Bs transferred to the United States Marine CorpsUnited States Marine CorpsThe United States Marine Corps is a branch of the United States Armed Forces responsible for providing power projection from the sea, using the mobility of the United States Navy to deliver combined-arms task forces rapidly. It is one of seven uniformed services of the United States...
and United States NavyUnited States NavyThe United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
.
0Y-2
- 152 transfers of L-5E to USN/USMC; 30 0Y-1 conversions to 24V electrical system.
Sentinel Mk I
- 40 L-5s supplied to the RAFRoyal Air ForceThe Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...
under Lend-LeaseLend-LeaseLend-Lease was the program under which the United States of America supplied the United Kingdom, the Soviet Union, China, Free France, and other Allied nations with materiel between 1941 and 1945. It was signed into law on March 11, 1941, a year and a half after the outbreak of war in Europe in...
.
Sentinel Mk II
- 60 L-5Bs supplied to the RAF under Lend-Lease.
Aircraft markings
Standard camouflage as delivered from the factory was non-specular "Bulletin 41" medium gray #43 undersides with olive drab #41 above, broken around the edges of the wing and tail surfaces with medium green #41. Stars, or "stars and bars" were applied to both sides of the fuselage and on the upper left and lower right wingtips. The USAAF number appeared on both sides of the vertical stabilizer in either yellow or black. The USMC number appeared in smaller size in black only. Most aircraft were repainted silver during the post-WWII period. Some Marine Corps and Navy aircraft painted overall non-specular Sea Blue. A variety of unit identification markings including nose art were applied in the field. Interior surfaces were generally finished in yellow-green chromate primer and slightly darker ANA 611 "interior green". Instrument panels were "raw" phenolic sheet naturally matte black in color.Units using this aircraft
The USAAF, US Marines, and US Navy used this aircraft in the European, Pacific, and Far East theaters during World War II, and in KoreaKorea
Korea ) is an East Asian geographic region that is currently divided into two separate sovereign states — North Korea and South Korea. Located on the Korean Peninsula, Korea is bordered by the People's Republic of China to the northwest, Russia to the northeast, and is separated from Japan to the...
during the Korean War
Korean War
The Korean War was a conventional war between South Korea, supported by the United Nations, and North Korea, supported by the People's Republic of China , with military material aid from the Soviet Union...
. The Royal Air Force operated 100 Sentinels in India and Burma.
After WWII, the Philippine Army Air Corps
Philippine Army Air Corps
The Philippine Army Air Corps was created by the Philippine National Assembly's National Defense Act of 1935. By 1940, the corps had around 40 aircraft and 100 pilots, 500 personnel, and six squadrons...
used this aircraft from 1945 to 1947. This aircraft remained in service after 1 July 1947 when the PAAC was renamed the Philippine Air Force
Philippine Air Force
The Philippine Air Force is the air force of the Republic of the Philippines, and one of the three main services of the Armed Forces of the Philippines. Its official name in Filipino is Hukbong Himpapawid ng Pilipinas....
. The Italian Air Force operated approximately 100 L-5's from 1946 into the 1950s. Many other countries also received L-5's after the war, particularly India which received 200. A number of these went to Pakistan after the partition of India in 1948.
Postwar use and current status
After World War IIWorld War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, the L-5 was widely used by the Civil Air Patrol
Civil Air Patrol
Civil Air Patrol is a Congressionally chartered, federally supported, non-profit corporation that serves as the official civilian auxiliary of the United States Air Force . CAP is a volunteer organization with an aviation-minded membership that includes people from all backgrounds, lifestyles, and...
for search and rescue work. Today there are about 300 known examples left world wide and less than half are in flying condition. A restored, flying example of the 0Y-1 (L-5E) variant (VH-NOY) is located in Coolangatta, Queensland
Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. This example was built for the USAAF but was delivered directly to the US Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
instead, serving until 1949. A group called the Sentinel Owners and Pilots Association is dedicated to the preservation and enjoyment of this aircraft type.
Operators
- Royal Australian Air ForceRoyal Australian Air ForceThe Royal Australian Air Force is the air force branch of the Australian Defence Force. The RAAF was formed in March 1921. It continues the traditions of the Australian Flying Corps , which was formed on 22 October 1912. The RAAF has taken part in many of the 20th century's major conflicts...
- The RAAF operated one L-5 Sentinel, on loan from the USAAF. The aircraft was in service with the RAAF from 1944 to 1946.
- Italian Air ForceItalian Air ForceThe Italian Air Force has gone under different names in different periods:*Regia Aeronautica , from 1923 to June 1946*Aeronautica Nazionale Repubblicana, the air force of Italian Social Republic during World War II...
- National Security Force
- Japan Ground Self-Defense ForceJapan Ground Self-Defense ForceThe , or JGSDF, is the army of Japan. The largest of the three services of the Japan Self-Defense Forces, the Ground Self-Defense Force operates under the command of the chief of the ground staff, based in the city of Ichigaya, Tokyo. The present chief of ground staff is General Yoshifumi Hibako...
- Republic of Korea Air ForceRepublic of Korea Air ForceThe Republic of Korea Air Force is the air force of South Korea...
- Philippine Army Air CorpsPhilippine Army Air CorpsThe Philippine Army Air Corps was created by the Philippine National Assembly's National Defense Act of 1935. By 1940, the corps had around 40 aircraft and 100 pilots, 500 personnel, and six squadrons...
- Philippine Air ForcePhilippine Air ForceThe Philippine Air Force is the air force of the Republic of the Philippines, and one of the three main services of the Armed Forces of the Philippines. Its official name in Filipino is Hukbong Himpapawid ng Pilipinas....
- ROC Air Force
- Royal Thai Air ForceRoyal Thai Air ForceThe Royal Thai Air Force or RTAF is the air force of the Kingdom of Thailand. Since its establishment in 1913, as one of the earliest air forces of Asia, the Royal Thai Air Force had engaged in many major and minor battles. During the Vietnam war era, the air force has been developed with USAF-aid...
- Royal Air ForceRoyal Air ForceThe Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...
- No. 27 Squadron RAFNo. 27 Squadron RAFNo. 27 Squadron of the Royal Air Force operates the Boeing Chinook HC2 from RAF Odiham.-The Great War:27 Squadron formed at Hounslow Heath Aerodrome on 5 November 1915, soon being equipped with Martinsyde Elephant fighter aircraft, hence the use of an elephant for the squadron badge...
- No. 117 Squadron RAFNo. 117 Squadron RAFNo. 117 Squadron RAF was a Royal Air Force Squadron formed to be a bomber unit in World War I and reformed as a transport and communications unit in World War II.-Formation and World War I:...
- No. 194 Squadron RAFNo. 194 Squadron RAF194 Squadron RAF, though formed as a training unit in Egypt and ended as a casualty evacuation unit in Malaya, was for most of its active service life a RAF transport squadron that flew in South East Asia.-Formation and World War I:...
- No. 27 Squadron RAF
- Civil Air PatrolCivil Air PatrolCivil Air Patrol is a Congressionally chartered, federally supported, non-profit corporation that serves as the official civilian auxiliary of the United States Air Force . CAP is a volunteer organization with an aviation-minded membership that includes people from all backgrounds, lifestyles, and...
- United States Army Air Force
- United States Air ForceUnited States Air ForceThe United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...
- United States Marine CorpsUnited States Marine CorpsThe United States Marine Corps is a branch of the United States Armed Forces responsible for providing power projection from the sea, using the mobility of the United States Navy to deliver combined-arms task forces rapidly. It is one of seven uniformed services of the United States...
- United States NavyUnited States NavyThe United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
Survivors
- Jimmy Doolittle Air & Space MuseumJimmy Doolittle Air & Space MuseumThe Jimmy Doolittle Air & Space Museum is an extensive aviation museum located at Travis Air Force Base in Fairfield, California. The museum houses 35+ aircraft displays and various other informative artifacts.-History:...
, Travis Air Force BaseTravis Air Force BaseTravis Air Force Base is a United States Air Force air base under the operational control of the Air Mobility Command , located three miles east of the central business district of Fairfield, in Solano County, California, United States. The base is named for Brigadier General Robert F...
, Fairfield, CaliforniaFairfield, CaliforniaFairfield is a city located in Solano County in Northern California, USA. It is generally considered the midpoint between the cities of San Francisco and Sacramento, approximately from the city center of both cities, approximately from the city center of Oakland, less than from Napa Valley, 18...
Specifications (L-5)
External links
- Sentinel Owners and Pilots Association (SOPA), an organization dedicated to restoring, flying, maintaining and increasing public awareness of the Stinson L-5.