The Boeing Model 40 was a United States mail plane of the 1920s. It was a single-engined biplane that was widely used for airmail services in the United States in the 1920s and 1930s, especially by airlines that later became part of United Airlines. It became the first aircraft built by the Boeing company to carry passengers.
|First flight||July 20, 1925|
|Introduction||July 1, 1927|
|Primary users||Boeing Air Transport|
Varney Air Lines
Pacific Air Transport
|Number built||ca. 80|
In 1925, the US Post Office issued a requirement for a mailplane to replace the ex-military DH-4s then in use. The new aircraft was required to use the same water-cooled Liberty V12 engine as used by the DH-4, of which large stocks of war-built engines were available. The resultant aircraft, the Boeing Model 40, was a conventional tractor biplane, with the required Liberty engine housed in a streamlined cowling with an underslung radiator. The aircraft's fuselage had a steel tube structure, with an aluminum and laminated wood covering. Up to 1,000 lb (450 kg) of mail was carried in two compartments in the forward fuselage, while the single pilot sat in an open cockpit in the rear fuselage. The wings and tail were of wooden construction, and the Model 40 had a fixed conventional landing gear.
The Contract Air Mail Act of 1925 set out the gradual privatization of the Post Office's Air Mail routes. In late 1926, bids were requested for the main transcontinental trunk mail route, which was to be split into eastern and western sections, with Boeing bidding for the western section. Boeing revived the design for the tender, with the Model 40A replacing the Liberty engine with a 425 hp (317 kW) air-cooled Pratt & Whitney Wasp radial engine, which was 200 lb (91 kg) lighter than the Liberty, ignoring the weight of the Liberty's radiator and cooling water. The fuselage was redesigned to make more extensive use of welded steel tubing, and an enclosed cabin was fitted between the mail compartments, allowing two passengers to be carried as well as 1,200 lb (540 kg) of mail. Boeing's bid of $3 per lb was much less than any of the competing bids, and Boeing was awarded the San Francisco to Chicago contract in January 1927, building 24 Model 40As for the route (with a further aircraft being used as a testbed by Pratt & Whitney).
The next model to reach production was the Model 40C, with an enlarged cabin allowing four passengers to be carried. Meanwhile, Boeing Air Transport's Model 40As were modified by replacing their Wasp engines with 525 hp (391 kW) Pratt & Whitney Hornet radial engines to become the Model 40B-2. The Model 40B-4 was a new-build aircraft combining the four-passenger cabin of the Model 40C with the Hornet engine of the B-2. Production continued until February 1932.
Boeing's airline, Boeing Air Transport, commenced operations on the San Francisco–Chicago route on July 1, 1927.
As of February 17, 2008, Boeing 40C c/n 1043 became the only airworthy example in the world. It also holds the title of the oldest flying Boeing in the world. In 1928, the aircraft was substantially damaged in a crash near Canyonville, OR. After being recovered, it was completely rebuilt over an eight-year period from 2000 to 2008 and an estimated 18,000 man hours by Pemberton and Sons Aviation in Spokane, Washington. On May 8, 2010, this airplane had an aerial rendezvous with Boeing's newest passenger aircraft, the Boeing 787 Dreamliner. In September, 2017, it was sold to the Western Antique Aeroplane & Automobile Museum in Hood River, Oregon. It remains airworthy and flies on special occasions.
The Museum of Flight in Seattle, Washington has a complete full-scale replica and two partially finished replica fuselages (showing what the original Boeing factory would have looked like circa 1928-29) on display.
Data from Boeing Aircraft since 1916
For the current active command, see Air Mobility CommandAir Transport Command (ATC) was a United States Air Force unit that was created during World War II as the strategic airlift component of the United States Army Air Forces.
It had two main missions, the first being the delivery of supplies and equipment between the United States and the overseas combat theaters; the second was the ferrying of aircraft from the manufacturing plants in the United States to where they were needed for training or for operational use in combat. ATC also operated a worldwide air transportation system for military personnel.
Inactivated on 1 June 1948, Air Transport Command was the precursor to what became the Military Air Transport Service in 1948 and was redesignated Military Airlift Command (MAC) in 1966. It was consolidated with MAC in 1982, providing a continuous history of long range airlift through 1992 when the mission was transferred to today's Air Mobility Command.Airmail
Airmail (or air mail) is a mail transport service branded and sold on the basis of at least one leg of its journey being by air. Airmail items typically arrive more quickly than surface mail, and usually cost more to send. Airmail may be the only option for sending mail to some destinations, such as overseas, if the mail cannot wait the time it would take to arrive by ship, sometimes weeks. The Universal Postal Union adopted comprehensive rules for airmail at its 1929 Postal Union Congress in London. Since the official language of the Universal Postal Union is French, airmail items worldwide are often marked Par avion, literally: "by airplane".
For about the first half century of its existence, transportation of mail via aircraft was usually categorized and sold as a separate service (airmail) from surface mail. Today it is often the case that mail service is categorized and sold according to transit time alone, with mode of transport (land, sea, air) being decided on the back end in dynamic intermodal combinations. Thus even "regular" mail may make part of its journey on an aircraft. Such "air-speeded" mail is different from nominal airmail in its branding, price, and priority of service.Claire Egtvedt
Clairmont L. "Claire" Egtvedt (1892–1975) was an airplane designer and president and chairman of the Boeing Company. Along with Ed Wells, he is considered to be the father of the Boeing B-17 bomber.Egtvedt was chief engineer on airplanes such as the B-1 mailplane, Boeing Model 15 and Boeing Model 21 pursuit airplanes, and the Boeing Model 40 airliner-mailplane. Though promoted to the executive ranks, he also participated heavily the design of the Boeing Model 80, XB-15, and B-17 models. As president, and later chairman of Boeing he oversaw and approved the development of the B-47, B-52, 707, 727,737, and 747. Flight Global ranked Egtvedt 2nd behind William McPherson Allen as most impactful Boeing boss.History of United Airlines
United Airlines is the third largest airline in the world, with 86,852 employees (which includes the entire holding company United Airlines Holdings) and 721 aircraft. It was the brainchild of William Boeing and emerged from his consolidation of numerous carriers and equipment manufacturers from 1928 to 1930.List of civil aircraft
List of civil aircraft is a list of articles on civilian aircraft with descriptions, which excludes aircraft operated by military organizations in civil markings, warbirds, warbirds used for racing, replica warbirds and research aircraft.Mail plane
A mail plane is an aircraft used for carrying mail.
Aircraft that were purely mail planes existed almost exclusively prior to World War II. Because early aircraft were too underpowered to carry cargoes, and too costly to run any "economy class" passenger-carrying service, the main civilian role for aircraft was to carry letters faster than previously possible. In 1934, some mail services in the USA were operated by the United States Army Air Corps, soon ending in the Air Mail scandal.In the past, mail-carrying aircraft had to carry a special official emblem on the fuselages; in case of British-registered aircraft, a special Royal Air Mail pennant (a blue triangular flag with a crowned bugle emblem in yellow and the letters "ROYAL AIR MAIL" in white) would sometimes be flown as well.
From the late 1940s, mail planes became increasingly rare, as the increasing size of aircraft and economics dictated a move towards bulk carriage of mail onboard airline flights, and this remains the primary method today. Parcel mail, overnight mail and priority mail, however, are still carried aboard what may be considered the spiritual successors of classic, pre-war mail planes; small, general aviation aircraft that have been adapted to the role, with the Cessna 208 and Piper PA-31 Navajo being among the most popular. Cargo airline operators, such as UPS and FedEx, also carry mail along with bulk cargo, aboard converted airliners.Question Mark (aircraft)
Question Mark ("?") was a modified Atlantic-Fokker C-2A transport airplane of the United States Army Air Corps. In 1929, commanded by Major Carl A. Spaatz, it was flown for a flight endurance record as part of an experiment with aerial refueling. Question Mark established new world records in aviation for sustained flight (heavier-than-air), refueled flight, sustained flight (lighter-than-air), and distance between January 1 and January 7, 1929, in a non-stop flight of more than 150 hours near Los Angeles, California.
Following the record-setting demonstration, the C-2A was returned to transport duties. In 1931 more powerful engines replaced those used in the endurance flight and it was re-designated as a C-7 transport. The aircraft was damaged beyond economical repair in 1932 when it crash-landed in Texas after running out of fuel and was scrapped.
The flight demonstrated the military application of the concept, but while it inspired numerous efforts to set even greater endurance records, development of a practical in-flight refueling system was largely ignored by the world's air forces before World War II. Civilian development of aerial refueling in Great Britain was more successful, but in the end it, too, was disregarded. However, Spaatz, two decades after the flight of the Question Mark, became head of the United States Air Force and using the British system as a starting point, implemented in-flight refueling on a worldwide operational basis.Stearman 4
The Stearman 4 is an American commercial biplane that was manufactured in the 1920s by Stearman Aircraft. They were marketed at the time as fast and luxurious executive transports and mail planes for about US$16,000.Stearman M-2 Speedmail
The Stearman M-2 Speedmail (nicknamed the Bull Stearman) was a mail-carrier aircraft produced by the Stearman Aircraft Company of Wichita, Kansas. It first flew in January 1929. The Speedmail was a single seat biplane, with two large cargo compartments in place of a front cockpit. The fuselage and tail unit were constructed from welded chrome-moly steel tube faired with wooden formers and fabric covered aft of the pilots cockpit, detachable aluminium alloy panels covered the fuselage forward of the pilots cockpit. The wings were constructed from spruce spars and plywood built-up ribs, all fabric covered. It differed from previous Stearman aircraft by having a tailwheel instead of a tailskid due to its size and weight.United Airlines fleet
As of October 2019, United Airlines' fleet consists of the following aircraft: For information about the fleet of United Airlines' regional operations, see United Express (airline brand).
In a 2019 United Enhanced Equipment Trust Certificate, a new Embraer 175 mean valuation is $30.6-30.7 million, a Boeing 737 MAX-9 is $51.9-52.7 million and a Boeing 787-10 is $155.5- 156.3 million.
Boeing aircraft model numbers