Aircraft / Aviation Vehicles & Artillery Infantry Arms Warships & Submarines US Military Pay (2022) Global Military Ranks


Aviation / Aerospace

Thomas-Morse S-4

Advanced Flight Trainer Biplane Aircraft [ 1917 ]

The Thomas-Morse S-4 series of advanced flight training biplanes emerged during the World War 1 period from American aero-industry.

Authored By: Staff Writer | Last Edited: 11/09/2018 | Content ©www.MilitaryFactory.com | The following text is exclusive to this site.

What became the Thomas-Morse Aircraft concern of the United States was started in 1910 by brothers William Thomas and Oliver Thomas as the "Thomas Brothers Company". It remained in operation until 1929 when it was taken over by the Consolidated Aircraft Corporation - makers of the famous World War 2-era B-24 "Liberator" heavy bomber. From 1910 until that time, the brothers managed a healthy collection of products related to the world of aviation including the D-2, T-2, and S-4 offerings. The S-4 was of particular note, developed as an advanced flight trainer of biplane form and extensively utilized by the United States military during the World War 1 (1914-1918) period.

Over 500 of its type were produced and many ended up in private circulation after their military days had ended.

The United States entered World War 1 in April of 1917 following the sinking of the passenger ship Lusitania by German U-boat. This spurred American industry into action in support of the war effort in Europe. The S-4 owed its design roots to one Benjamin Thomas (unrelated to the brothers), and English engineer who had previously plied his trade with the famous Sopwith Aviation Company (makers of the classic Sopwith "Camel" biplane fighter of the First World War). The Thomas-Morse S-4 aircraft was constructed as soon as June 1917 and recorded its first-flight over Ithaca, New York, that same month. In this form, it carried a Gnome rotary engine of 100 horsepower output with two-bladed propeller unit.

The end-product was of traditional biplane wing arrangement with an upper and lower wing member in play supported by angled, parallel struts and cabling. The wings were of equal span and single-bay arrangement. A fixed, two-wheeled undercarriage with tailskid unit allowed for ground-running. The pilot sat in an open-air cockpit aft of the engine in the nose and under/aft the upper wing member. The tail unit was of conventional, single-rudder design. The engine fit drove a two-bladed wooden propeller in "puller"/"tractor" fashion consistent with the times.

Dimensions included a length of 19.9 feet, a wingspan of 26.5 feet, and a height of 8 feet. Gross weight became 1,330lb.
Three prototypes proved the S-4B model and this carried the Gnome rotary engine of 110 horsepower. Some 100 of this mark were ordered during the summer of 1917 with the U.S. Army taking a stock of 97 of the aircraft while the U.S. Navy added another six in floatplane configuration as the "S-5". The S-4B became the definitive advanced flight trainer for the U.S. air service for a good part of the war until succeeded by the S-4C mark. These were given Gnome B-9 series engines of 80 horsepower and were represented through six prototypes followed by some 461 serial aircraft, four also added (again, in floatplane arrangement) to the USN stable. After the 52nd example came off the line, the C-mark was updated with the Le Rhone 9C engine of 80 horsepower.

With the 9C engine unit, the aircraft could make top speeds nearing 100 miles per hour and fly up to a ceiling of 15,000 feet. Endurance was a 2.5 hour window giving good range for a trainer type. A single air-cooled 0.30 caliber Marlin machine gun could be installed for gunnery training.

In service, the aircraft became known as "Tommy".

A post-war attempt to sell the military on a new model, the S-4E, with revised tail unit and Le Rhone 9J 110 horsepower powerplant failed, leading to this aircraft being re-engined with an Aeromarine unit of 135 horsepower and flown by air racer Basil Rowe as the "Space-Eater"

The S-4 proved a quite the success for both the American Army and Navy during the wartime period as its numbers and popularity would eventually show. Their availability in number naturally led to many being acquired by way of surplus at the civilian market level in the post-war years where they continued on as trainers, racers, aerobatic performers, and flyable Hollywood props - such was their versatility. Many of these post-war models adopted the Curtiss OX-5 engine for drive power instead of the original military fits.


Service Year

United States national flag graphic
United States

Not in Service.


National flag of the United States United States
(OPERATORS list includes past, present, and future operators when applicable)
Training (General)
Developed ability to be used as a dedicated trainer for student pilots (typically under the supervision of an instructor).

19.8 ft
(6.05 m)
26.5 ft
(8.08 m)
8.0 ft
(2.45 m)
Empty Wgt
882 lb
(400 kg)
1,334 lb
(605 kg)
Wgt Diff
+452 lb
(+205 kg)
(Showcased structural values pertain to the Thomas-Morse S-4C production variant)
Installed: 1 x Le Rhone 9C air-cooled rotary piston engine developing 80 horsepower while driving a two-bladed wooden propeller unit at the nose.
Max Speed
96 mph
(155 kph | 84 kts)
14,764 ft
(4,500 m | 3 mi)
233 mi
(375 km | 694 nm)

♦ MACH Regime (Sonic)
RANGES (MPH) Subsonic: <614mph | Transonic: 614-921 | Supersonic: 921-3836 | Hypersonic: 3836-7673 | Hi-Hypersonic: 7673-19180 | Reentry: >19030

(Showcased performance specifications pertain to the Thomas-Morse S-4C production variant. Compare this aircraft entry against any other in our database or View aircraft by powerplant type)
1 x 0.30 caliber Marlin machine gun.

Supported Types

Graphical image of an aircraft medium machine gun

(Not all ordnance types may be represented in the showcase above)
Hardpoint Mountings: 0

S-4 - Base Series Designation
S-4B - Fitted with Gnome 110hp engine; three prototypes completed; 97 ordered by U.S. Army aviation and a further 10 examples for the USN.
S-5 - USN examples numbering six with floats for waterborne landings and take-offs.
S-4C - Succeeding B-model aircraft; six prototypes; completed with Gnome B-9 80hp (early) or Le Rhone C-9 80hp (52 aircraft onwards) engines; 461 examples to U.S. Army with four floatplane derivatives delivered to USN.
S-4E - One-off model with revised tail section and Le Rhone 9J rotary of 110hp for aerobatic service; later fitted with Aeromarine engine of 135hp for racing pilot Basil Rowe.

Military lapel ribbon for Operation Allied Force
Military lapel ribbon for the Arab-Israeli War
Military lapel ribbon for the Battle of Britain
Military lapel ribbon for the Battle of Midway
Military lapel ribbon for the Berlin Airlift
Military lapel ribbon for the Chaco War
Military lapel ribbon for the Cold War
Military lapel ribbon for the Cuban Missile Crisis
Military lapel ribbon for pioneering aircraft
Military lapel ribbon for the Falklands War
Military lapel ribbon for the French-Indochina War
Military lapel ribbon for the Golden Age of Flight
Military lapel ribbon for the 1991 Gulf War
Military lapel ribbon for the Indo-Pak Wars
Military lapel ribbon for the Iran-Iraq War
Military lapel ribbon for the Korean War
Military lapel ribbon for the 1982 Lebanon War
Military lapel ribbon for the Malayan Emergency
Military lapel ribbon representing modern aircraft
Military lapel ribbon for the attack on Pearl Harbor
Military lapel ribbon for the Six Day War
Military lapel ribbon for the Soviet-Afghan War
Military lapel ribbon for the Spanish Civil War
Military lapel ribbon for the Suez Crisis
Military lapel ribbon for the Ukranian-Russian War
Military lapel ribbon for the Vietnam War
Military lapel ribbon for Warsaw Pact of the Cold War-era
Military lapel ribbon for the WASP (WW2)
Military lapel ribbon for the World War 1
Military lapel ribbon for the World War 2
Military lapel ribbon for the Yom Kippur War
Military lapel ribbon for experimental x-plane aircraft

Ribbon graphics not necessarily indicative of actual historical campaign ribbons. Ribbons are clickable to their respective aerial campaigns / operations / aviation periods.

Images Gallery

1 / 4
Image copyright www.MilitaryFactory.com; No Reproduction Permitted.
2 / 4
Image copyright www.MilitaryFactory.com; No Reproduction Permitted.
3 / 4
Image copyright www.MilitaryFactory.com; No Reproduction Permitted.
4 / 4
Image copyright www.MilitaryFactory.com; No Reproduction Permitted.


Disclaimer | Privacy Policy | Cookies

2022 US Military Pay Army Ranks Navy Ranks Marine Ranks Air Force Ranks USCG Ranks Compare Ranks (NEW!) DoD Dictionary Military Ribbons Identification Military Alphabet Code Military Map Symbols American War Deaths French Military Victories Vietnam War Casualties

The "Military Factory" name and MilitaryFactory.com logo are registered ® U.S. trademarks protected by all applicable domestic and international intellectual property laws. All written content, illustrations, and photography are unique to this website (unless where indicated) and not for reuse/reproduction in any form. Material presented throughout this website is for historical and entertainment value only and should not to be construed as usable for hardware restoration, maintenance, or general operation. We do not sell any of the items showcased on this site. Please direct all other inquiries to militaryfactory AT gmail.com.

Part of a network of sites that includes GlobalFirepower, a data-driven property used in ranking the top military powers of the world, WDMMA.org (World Directory of Modern Military Aircraft), WDMMW.org (World Directory of Modern Military Warships), and SR71blackbird.org, detailing the history of the world's most iconic spyplane.

www.MilitaryFactory.com • All Rights Reserved • Content ©2003-