Stinson L-5 Sentinel

The L-5 was a purpose-built military airplane; similar but different in design were the preceding commercial Stinson HW-75 series (a.k.a. Model 105) and Model 10 (a.k.a. 10A Voyager) aircraft.* Six Model 10s were purchased by the AAF in 1941 under the nomenclature YO-54. Quantity orders for a slightly larger and heavier Model 76 Sentinel (all-new to meet military requirements) began in 1942, first as the O-62 before the designation was changed to “L” for liaison in April of the same year. Between 1942 and 1945, the AAF ordered 3,590 L‑5 aircraft.

The Stinson L-5 was adopted as a replacement for the much larger and more expensive Stinson O-49 Vigilant (L-1). By the end of WWII, the L-5 was the second most widely used liaison aircraft. It was rugged and powerful. The L‑5 was unarmed and designed with short field takeoff and landing (STOL) capability. It was often referred to as the Flying Jeep.

The L-5 served in every possible role including artillery spotting, supplying soldiers behind enemy lines, performing courier service, and serving in medical evacuation. It was used for reconnaissance, removing litter patients from front line areas, delivering supplies to isolated units, laying communications wire, spotting enemy targets for attack aircraft, transporting personnel, rescuing Allied personnel in remote areas, and even for light bombing. In Asia and the Pacific, the L‑5 remained in service with USAF units as late as 1955.

Alamo Liaison Squadron’s L-5 Sentinel “Burma Babe” was built in an ambulance configuration accommodating a medevac litter in the rear hatch with the rear seat folded down. Demonstration flights of the L‑5 performing a battlefield pick-up are given at the squadron’s annual fly-in event at Cannon Field.

In total 3,591 were built for the U.S. Armed Forces, making the L-5 the second most widely used light observation aircraft of the war behind the Piper L-4. An additional 31 units of the L-5 were completed and sold post-WWII on the civil market.

Note: The L-5 was equipped with an electric starter, landing and navigation lights, flaps, leading edge slats, and a parking brake. By comparison the L-4 had none of these features.

Your tax deductible donation will help to support the preservation of this aircraft.

If you prefer to give by mail, send your check payable to: Alamo Liaison Squadron, 2352 S. Loop 1604 W., San Antonio, Texas 78264. Please write “Donation” in the memo line.

The L-5 was the largest of the liaison aircraft serving in WWII. An excerpt from Ken Wakefield’s The Other Ninth Air Force: November 6, 1944 – Visit from 30th Inf Div Arty Air Officer (Maj. Blohm) to discuss supply matters. He believes it imperative than an L-5 be assigned to Div Arty HQ (the Commanding General weighs over 200 Ibs and likes to fly).

Also from Ken Wakefield’s The Other Ninth Air Force: A worthwhile experiment during the month [December 1944] had been the installation of a K-22 camera in one of the 125th’s L-5s. The Fairchild K-22 was a high-altitude, standard day reconnaissance camera designed for ground and target intelligence spotting and for both vertical and oblique photography. It had an Eastman Kodak Aero Ektar lens, a focal plane shutter, and a 24-inch lens. The K-22 was used on such aircraft as the Boeing B 29, Douglas A-20, and North American P-51 and F-86.

The L-5 was produced by the Stinson Division of the Vultee Aircraft Company. During the L-5s tenure, Stinson, as an aircraft design and manufacturing entity, would become part of Consolidated Vultee on the merger of the two companies in 1943. More than half of the total L-5 production (2,526 units) was completed prior to the merger. Stinson remained in Wayne, Michigan as the Stinson Division of Consolidated Vultee. While all production of the L-5 had ended in 1945, the Stinson company was sold to the Piper Aircraft Corporation in 1948.

Read more about the L-5 in service in Interprète Volant a rare book written by a commissioned French interpreter who traveled with the 72nd Liaison Squadron during the push back of German troops from 1944–1945. Composed later from a notebook kept during his time with the squadron, author Jean Ably reconstructs the daily routines of his traveling companion officers, soldiers and American airmen. He extolls the virtues of marching with the aid of an airplane through his native France, and later into Germany. An indispensable tool was the L-5 for the transport of personnel in advance of troops and on exploratory missions into otherwise inaccessible areas.

* The following clarification was provided by Jim Gray of the Sentinel Owners and Pilots Association:

The Stinson marketing department caused all sorts of confusion. They called the HW-75 the 105 because it supposedly cruised at 105 mph, but on the type certificate, it says HW-75. No mention of 105. They were available in 75- and 80-hp versions. Then, they came out with the “New 105 for 1940” at the end of 1939, which is how the national advertising billed it, which had only minor changes but the 80-hp engine was now standard.

In the spring of 1940, the fuselage cabin was widened by about two inches and they called this the Model 10, which is also on the type certificate (but not HW-80). This is what was sold to the military in August 1940 as the YO-54, with the addition of a radio and wind-generator to keep the battery charged. Two months before they were delivered, Stinson had already flight-tested the tandem-seat Model 75B.

After Stinson became a subsidiary of Vultee in August, they came out with the Franklin-powered 90-hp version with redesigned cowl, fancy upholstery, full electrical system with generator, a new paint scheme, and other “improvements.” This was marketed as the Voyager (Gen. Patton bought one in 1941). They also offered a stripped-down 80-hp version of the Voyager dubbed the 10B. The 10A and 10B were manufactured under a new type certificate that does not include the “Voyager” name or the designation HW-90. The military purchased 20 Voyagers and these are what became the L-9. What is odd and adds to the confusion is that the 10A became the L-9B. Go figure!

In the meantime, a miscommunication with the military about the YO-54s temporarily misidentified them as Model 105s until the chief engineer at Stinson got that screw-up straightened out, explaining in a letter to Wright Field that they were in fact Model 10s, but the damage had been done and 105 got published in some of the literature of the period, hence the confusion ever since. And, of course, most people (and the media) have mistakenly called all of them Voyagers because they all are quite similar if one doesn’t look too closely. Likewise, HW-80 and HW-90 do not appear to be official engineering designations for them either, and those designations are not on the type certificates, further adding confusion to what has been widely published for 70 years.

The Sentinel Owners and Pilots Association can be reached at sentinelclub.org.