×
Aircraft / Aviation Vehicles & Artillery Infantry Arms Warships & Submarines Military Pay Scale Military Ranks
HOME
AIRCRAFT / AVIATION
MODERN AIR FORCES
COUNTRIES
MANUFACTURERS
COMPARE
BY CONFLICT
BY TYPE
BY DECADE
GOLDEN AGE

Boeing Model 40


Mailplane Transport Biplane (1927)


Aviation / Aerospace

1 / 6
Image copyright www.MilitaryFactory.com; No Reproduction Permitted.
2 / 6
Image copyright www.MilitaryFactory.com; No Reproduction Permitted.
3 / 6
Image copyright www.MilitaryFactory.com; No Reproduction Permitted.
4 / 6
Image copyright www.MilitaryFactory.com; No Reproduction Permitted.
5 / 6
Image copyright www.MilitaryFactory.com; No Reproduction Permitted.
6 / 6
Image from the Public Domain.

Jump-to: Specifications

Fewer than 100 Boeing Model 40s were produced in the latter part of the 1920s - these serving with a select few global operators.



Authored By: Staff Writer | Last Edited: 04/01/2019 | Content ©www.MilitaryFactory.com | The following text is exclusive to this site.
One of the earlier, effective uses of the airplane outside of the military realm was in mail delivery. Until this point in history, mail arrived view rail or other ground-based method. Some aircraft designs were developed exclusively for the mail delivery service and generally built around good speed and inherently strong hauling capabilities. Boeing did just that with its Model 40 which undertook its first flight on July 20th, 1925 and introduced the product in July of 1927. About 80 of the type were ultimately built and served several transport lines of the day (including Boeing Air Transport).

The aircraft was originally developed to a new requirement put forth by the United States Postal Service (USPS). Up to this point, the service relied on the British de Havilland DH.4 biplane which appeared during the fighting of World War 1 (1914-1918) in 1917. Nearly 6,300 of the two-seat biplane light bombers were produced with a bulk of this (including its Liberty engines) emerging from American factories. The line went on to influence subsequent aircraft such as the DH-9 detailed elsewhere on this site.

To ease development and production, the same Liberty engines used by the wartime version of the aircraft would be featured in the new mail plane. A biplane wing arrangement was retained and the tail unit sported a conventional single-finned configuration. The open-air, single-seat cockpit was seated aft and under the upper wing element. The undercarriage was fixed and wheeled at all three legs. The exposed Liberty V12 radial engine was fitted in the nose and drove a two-bladed propeller. Steel tubing, aluminum, wood and fabric were used in the aircraft's general construction makeup. The original aircraft held a cargo capacity of 1,000 lb.

The resultant design was the Boeing "Model 40". The USPS ended up pursuing the competing Douglas M series instead after securing the Boeing prototype. However, the Contract Air Mail Act of 1925 opened two fronts in the mail service approach, an eastern and western region, and Boeing looked to secure its aircraft for the latter routes. This involved revising the Model 40 into the "Model 40A" to make for a more tempting product in which a key change was introduction of the lighter weight Pratt & Whitney "Wasp" radial engine of 425 horsepower output. An interesting addition was a two-person cabin fitted between the upper and lower wing elements where each position was given a hinged, automobile-style access door and viewing windows. In terms of cargo, the aircraft improved its hauling capacity to 1,200 pounds of mail goods.

Twenty-five Model 40A aircraft were purchased and some were eventually fitted with Pratt & Whitney "Hornet" engines of 525 horsepower for improved performance. This produced the Model 40B-2 variant which were essentially re-engined Model 40A aircraft. The Model 40B-4 designation marked new production aircraft fitted with Hornet engines from the outset. The Model 40B series was followed by the "Model 40C" which could seat four persons in its cabin space.

Beyond the United States, the Model 40 was featured as part of the Honduran Air Force service and a pair are known to have been delivered to New Zealand. Boeing Canada added aircraft to the total production stock through a few of its Model 40H-4 variant.

Performance from this interwar biplane (in particular the Model 40A) included a maximum speed of 128 miles per hour, a cruise speed of 105 miles per hour, a range out to 650 miles, a service ceiling of 14,500 feet and a rate-of-climb of 770 feet per minute.

Specifications



Service Year
1927

Origin
United States national flag graphic
United States

Status
RETIRED
Not in Service.
Crew
1

Production
80
UNITS


Boeing - USA
National flag of Canada National flag of New Zealand National flag of the United States Canada; Honduras; New Zealand; United States
(OPERATORS list includes past, present, and future operators when applicable)
Transport
General transport functionality to move supplies/cargo or personnel (including wounded and VIP) over range.
Commercial Aviation
Used in roles serving the commercial aviation market, ferrying both passengers and goods over range.


Length
33.1 ft
(10.10 m)
Width/Span
44.3 ft
(13.50 m)
Height
12.3 ft
(3.75 m)
Empty Wgt
3,538 lb
(1,605 kg)
MTOW
6,019 lb
(2,730 kg)
Wgt Diff
+2,480 lb
(+1,125 kg)
(Showcased structural values pertain to the base Boeing Model 40 production variant)
Installed: 1 x Pratt & Whitney Wasp radial piston engine developing 420 horsepower.
Max Speed
127 mph
(205 kph | 111 kts)
Ceiling
14,501 ft
(4,420 m | 3 mi)
Range
649 mi
(1,045 km | 1,935 nm)
Rate-of-Climb
770 ft/min
(235 m/min)


♦ MACH Regime (Sonic)
Sub
Trans
Super
Hyper
HiHyper
ReEntry
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 base Boeing Model 40 production variant. Compare this aircraft entry against any other in our database. View aircraft by powerplant type)
None.


Model 40 - Base Series Designation; original model of 1925 with Liberty powerplant.
Model 40A - Fitted with PW Wasp radial engine; two-seat passenger compartment; 25 examples.
Model 40B - Fitted with PW Hornet radial engine
Model 40B-2 - Re-engined Model 40A with Hornet engine; 19 examples.
Model 40B-4 - Four-passenger cabin seating; 38 examples completed.
Model 40B-4A - Engine testbed airframe
Model 40H-4 - Boeing Canada Model 40B-4; four examples
Model 40C - PW Wasp engine; ten examples
Model 40X - Special variant based on Model 40C with two passenger seating in cabin; forward cockpit ahead of pilot.
Model 40Y - Special variant based on the Modle 40X; PW Hornet engine used.


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 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.

Disclaimer | Privacy Policy | Cookies


2021 Military Pay Scale Army Ranks Navy Ranks Air Force Ranks Alphabet Code DoD Dictionary 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, the World Directory of Modern Military Aircraft, and SR71blackbird.org, detailing the history of the world's most iconic spyplane.


Facebook Logo YouTube Logo

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