The History of the Boeing Model 40

A Contribution to Corporate and Air Line Growth

Boeing Historical Archives Boeing Historical Archives

45th AIAA Aerospace Sciences Meeting and Exhibit

January 7-10, 2008 Grand Serra Resort Hotel Reno, Nevada

Mike Lavelle, Associate Fellow AIAA Fellow, Royal Aeronautical Society Museum of Flight Seattle, Washington

Dedication

This paper is dedicated to Mr. William E. Boeing Jr. for his stewardship and continuous support of aviation/aerospace education.

Author and Mr. William E. Boeing Jr. Boeing Model 40B Roll Out Wenatchee, WA. October 6, 2007

This paper is copy write by author and The American Institute of Aeronautics and Astronautics 2008

2 Acknowledgements

This paper has been supported in one way or another by many people with whom I work. I like to thank them all for their time, assistance and feedback they provided while the paper was in the process of being researched and written.

The Museum of Flight Staff • Alison Bailey - Associate Director of Development Museum of Flight • Andrew Boike - Annual Fund Coordinator Museum of Flight • Meredith Downs – Photo Archivist Museum of Flight • John Little – Exhibits Technician and Aviation Historian • Ernst Marris – Security Officer Museum of Flight • Dennis Parks – Director of Collections Museum of Flight • Katherine Williams – Archivist Dahlberg Center for Military Aviation History, Museum of Flight

The Boeing Company Archives Staff • Mike Lombardi - The Boeing Company – Corporate Historian • Tom Lubbesmeyer – Boeing Historian \Archivist

Museum of Flight Trustee

• Brien S. Wygle – Retired Boeing Vice President and Company Test Pilot

I would especially like to thank Andrew Boike and Brien Wygle who spent their own time helping with the papers editing and format.

This paper is copy write by author and The American Institute of Aeronautics and Astronautics 2008

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Outline

The History of the Boeing Model 40 A Contribution to Corporate and Air Line Growth

• Introduction and Background o Overview Post Office Operations until 1923 o Early Aircraft used o Need for Updated equipment

• The Contenders for the de Havilland DH-4 Replacement o The industry response o Boeing Model 40 Overall Performance o Boeing’s Design approach

• Establishing the Industry o Events leading to Model 40 redesign o The Pratt & Whitney Aircraft Company

• Bringing the Boeing Model 40A into Production o Key events and Activities o The Boeing Model 40 Line Operations o United Aircraft and Transportation Corporation o How many were built and What Model 40 is it

• Where are they now – The Boeing Model 40 survivors and replicas.

• Pictures of the constructions of The Museum of Flight Model 40 replica under construction.

• Summary and conclusion.

• References

• About the Author

This paper is copy write by author and The American Institute of Aeronautics and Astronautics 2008

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The History of the Boeing Model 40

Introduction and Background

Overview of Post Office Operations until 1923

Aviation historian called 1919 the “First Year of Air Transportation”. That year marked the advent of the postwar passenger-carrying airplane; it was born amidst the glut of surplus wartime airplanes from all the combatants’ air arms. Within two months of the armistice, on January 8, 1919, Germany authorized airline development. The first German airline was the Deutsche Luft Reederei (D.L.R.), which opened passenger service between Berlin and Weimar, via Leipzig with war-surplus A.E.G. and D.F.W. biplanes. While in France, the Farman Brothers, well known aircraft designers before and during World War I opened scheduled service between Paris and Brussels using the Farman F.60 Goliath (figure 1a) in March of 1919. The British soon followed in August of 1919 when Aircraft Transport and Travel Ltd flew a modified D.H. 4A,(figure 1b) from London to Paris carrying cargo and one passenger initiating the first scheduled international air service. (Hallion 1977 p8) As we shall see the DH-4 also played a major role in the U.S. air transportation system with the U.S Postal Air Service.

Kenneth Munson Illustration Farman F.60 Goliath (1a)

de Havilland D.H. 4A (1b)

Figure 1

In the United States the development of schedule commercial aviation did not start with passenger service as in Europe but was tied closely with the efforts of the United States Post Office. When the US Army began flying the mail from New

5 York to Washington D.C with Philadelphia as an intermediate stop in May of 1918, few realized that within less than two and half years this nascent 215-mile route would grow into a 3000 mile transcontinental air mail line. The initial force and credit behind this growth was Assistant Postmaster General Otto Praeger who by August of 1918 transitioned Army mail flights to civilian Post Office operations. Praeger, a self-taught former Washington D.C. correspondent from Texas was a demanding chief. During the summer of 1918, he appointed personnel to key management positions. One such person was Captain Benjamin Lipsner who resigned from the Army to become the first Superintendent of the Air Mail. Lipsner in turn hired qualified pilots, selected aircraft, and established logistical support along the Post Office’s route structure.

Post Office Air Mail Routes 1918-1921 From R.E.G. Davies Airlines of the United States Since 1914

Figure 2

During the first year of operations, the Post Office realized an operational profit of $19,000. Postal revenues for the year totaled $162,000, while the cost to fly the mail was $143,000. The initial year of operations would be the only time that the airmail service generated a profit.

Early Aircraft Used

6 However, this is understandable given the swift route expansions illustrated by Figure 2. During this growth period, the Post Office was trying to find the optimum aircraft for the route as the line expanded west. The Post Office utilized mostly World War I surplus aircraft that included the Curtiss JN-4H and, Army surplus de Havilland DH-4s. There was also a mix of new post war aircraft. Such as the seven Standard Aircraft Company’s JR-1Bs (figure 3a) and a new post World War I design, the all-metal German Junkers JL-6. (figure 3b).

www.postalmuseum.si.edu Standard Aircraft Company JR-1B (3a)

www.postalmuseum.si.edu All-Metal Junker JL-6 (3b)

Figure 3

As a point of interest the Standard’s were the first non-military aircraft the U.S. Government purchased for $3500 each. They had 150 H.P. Hispanso-Suiza engines and could climb to 6000 feet faster than the Curtiss Jenny JN-4Hs. This would be an important performance consideration along the mountainous sections of the route.

Early in fiscal year 1921 the Post Office paid aircraft manufactures $476,000 for new and modified aircraft. However, when they could not find the ideal aircraft for

7 their operational needs they selected what was considered to be best of what they had and began a program of standardization.

The specific reasons for retiring these aircraft varied but generally included one or more of the following reasons, high cost of maintenance, safety, efficiency and/or overall aircraft performance. Figure 4 lists the aircraft types phased out.

Aircraft Phased out

• 7 Curtiss JN-4Hs 3 Glenn Martin Mailplanes • 7 Standard JR-1Bs 4 Junker JL 6s (F-13) • 17 Curtiss R-4ls 1 L,W.F. Type V • 20 Twin DH’s 2 Curtiss H-as

Figure 4

Boeing Historical Archives

de Havilland DH-4

Figure 5

Although a World War I British design the de Havilland DH-4 (figure 5) emerged from this pack of mixed aircraft a reliable work horse along the transcontinental route until the Post Office would turn their routes over to industry contractors at the beginning in 1926.

During World War I the DH-4 was built for the Army Air Service by the Dayton- Wright Aircraft Company under license agreement from the Airco consortium of Great Britain. The American version of the aircraft was powered by a 12 cylinder 400 HP Liberty Engine. After World War I the Army Air Service had several

8 aircraft manufactures modernize the DH-4 airframe. For example, Boeing modernized one hundred airframes between March 6 and July 1, 1920 by repositioning the fuel tanks and pilot’s cockpit. This improved the safety of flight in the event of an engine fire. Additionally, the landing gear was also moved forward slightly to improve ground handling. In 1923 Boeing further improved DH- 4s by converting several airframes from wood to steel. Intended primarily for the Army, many of the modernized (DH-4M’s) were transferred to the Post Office, remaining in service until it ceased flying the mail in 1927.

By mid-1924, using primarily the DH-4, regularly scheduled transcontinental mail service became a reality. In addition, to day flights, the Post Office pilots began regular night flights. They were guided by a lighted airway system with rotating beacons and brightly lit emergency landing fields, timing their night flying to reach the end of the lighted airway by daybreak. The Post Office resumed using special airmail postage, which it had discontinued in 1919. By 1924 Airmail now cost eight cents to travel in any of the three zones comprising the transcontinental route and could travel across the country for 24 cents. By the end of 1924, airmail planes were routinely completing the New York to San Francisco route within 34 hours.

Need for Updated Equipment

On April 7, 1924 realizing the need to replace the aging DH-4 fleet, the Post Office requested proposals from interested companies for an aircraft based on the following specifications:

• Liberty Motor • Cruising Speed at least 95 M.P.H. • Landing Speed 50 M.P.H. or less • Service Ceiling 15,000ft. • Pay load (mail) not less than 1000 pounds • Cargo space not less than 50 cubic feet • Fuel - cruising range 450 miles

Other requirements included: crash-proof gasoline tanks conforming to Army specifications, seat type to accommodate a parachute worn by the pilot, and a statement of materials and unit stresses to be used in the construction of primary structural parts. Other provisions specified that the design had to be easy to produce, allow rapid replacement of engine or other components while being mechanically simple to maintain. (Boeing Historical Archives)

At the time, the major Post Office requirement specified the aircraft needed to use the well-proven and somewhat reliable Liberty 400 HP engine. This requirement had at the time sound rational behind it.

9 The Liberty 12-cylinder water-cooled engine was America's greatest technological contribution to aircraft design and development during WWI (figure 6). Rated between 400-450 hp, it weighed only two pounds per horsepower, far surpassing similar types of engines mass-produced by England, France, Italy, and Germany at that time. During the war, Packard, Lincoln, Ford, General Motors, Nordyke, and Marmon produced 20,478 Liberty 12s. They were used primarily in U.S.-built D.H.4s. With the Post Office, operating DH-4s along their routes the pilots and maintenance personnel had extensive operational experience with their performance, maintenance and idiosyncrasies. Additionally, the Post Office Department had over two hundred Liberty 12 engines with associated spare parts in their inventory.

Boeing Historical Archives Liberty 12 – In For Maintenance Figure 6

Since the new air-cooled radial engines in design with The Wright Company and Pratt & Whitney were not yet fully developed, the Liberty was the logical engine of choice for the Post Office’s objective of developing a reliable airmail plane (Smith 1981 p111-112). The goal at this point was not to advance new aircraft development as much as improve bottom-line cost and low risk investment. While at the same time they would be expanding the mail service routes with reliability and consistent operations. Consequently, the Liberty engine requirement produced from the aircraft manufactures who offered aircraft for Post Office evaluation similar performance numbers as indicate for three aircraft companies listed in figure 8.

During the same time frame, there was pressure from Congress to reduce the cost of flying the mail by turning the routes over to private contactors. The passage of the 1925 Air Mail Act (Kelly Act) brought that concept into reality. However before the 1925 Air Mail Act came into effect several manufactures submitted designs to the Post Office for evaluation.

10 The Contenders for the de Havilland DH-4 Replacement

The Industry Response

Bids were submitted to the Post Office purchasing Agent in Washington, D.C. on July 15, 1925. Eleven aircraft manufactures (figure 7) tendered design proposals with cost breakdowns for aircraft produced in lots of three to fifty. (Boeing Historical Archives). The aircraft companies submitting proposals are listed in figure 7.

The Douglas Co. Santa Monica, Calif. The Boeing Airplane Co. Seattle Washington The Kurz-Kacch Co. Dayton Ohio. Aerial Service Corp. Hammondsport, N.Y. Lawson Aircraft Co. Inc. New York City Huff Daland & Co. Ogdensburg, N.Y, Curtiss Aeroplane & Motor Co. Garden City N.Y. Cox-Klemin Aircraft Corp. Baldwin, Long Island Consolidated Aircraft Corp. Buffalo, N.Y. G.Elias & Bro., Inc Buffalo, N.Y. Sikorsky Aero Engineering Corp New York City Post Office - De Havilland DH-4 Aircraft Replacement Bidders Figure 7 . The Boeing Airplane Company entered the Model 40 Mailplane prototype in the competition. Other manufactures in the competition that provided aircraft for evaluation included Douglas Aircraft, of Santa Monica, California with their M-1 Mailplane and Curtiss Aeroplane and Motor Company of Garden City, New York with their first commercial aircraft since 1919 called the “Carrier Pigeon”. (Bower, 1979). Of course no one knew it at the time but this would be the first of many competitive commercial aircraft product battles between Boeing and Douglas they would have against each other over the next 72 years until they merged in 1997.

Boeing Model 40 Overall Performance

Figure 8 shows the three main aircraft three contenders the Post Office evaluated along the air mail route structure to replace the DH-4. The winning design had the potential for a production order of 50 aircraft or more. The Douglas proposal for a production lot of three aircraft was $16,500 per aircraft decreasing to $12,500 per aircraft for a lot order of 50. The Boeing Airplane Company was $23,000 per example for three aircraft and $11,000 per aircraft for 50. The highest bidder was Sikorsky Engineering Corporation coming in at $27,000 per aircraft for a lot of three. The low bidder was the Kurz-Kacch Co. with $8,000 for a lot of three aircraft. (Boeing Historical Archives) It is interesting to note when reviewing figure 7 above that of the eleven companies submitting

11 bids eight were from New York State, mostly from the New York City area. Clearly, one could conclude the geographic center of aircraft engineering and manufacturing during the 1920’s in the United States was on the east coast. Eventually, with Douglas and Boeing established on the west coast they would with the help others, such as, North American and Consolidated Aircraft shift aircraft engineering and manufacturing to west coast of the Untied States by 1945.

Boeing Model 40 Douglas DAM-1 Curtiss Carrier Pigeon

Curtiss Carrier Aircraft Boeing Model 40 Douglas M-1 Pigeon First Flight 7-Jul-25 6-Jul-25 # Produced Prototype Prototype Pilot & Pax Pilot Only Pilot / 2 Optional Pax Pilot Powerplant Liberty 400 h.p. Liberty 400 h.p. Liberty 400 h.p. Wing Span 44'2" 39'8" 41"11" Length 33'2" 28'11" 28" 9.5" Height 12'3" 10'1" 12"1" Empty Weight 3,425 lbs 2,885lbs 3603 lbs Gross Weight 5,495 lbs 4,775" 5620 lbs Speed 135 m.p.h 145 m.p.h. 125 m.p.h. Range 700 miles 600 miles 525 miles ceiling 15,800' 17,000' 12,800' Basic Specifications of aircraft evaluated by the Post Office 1925 Figure 8

When one studies the overall dimensions and performance numbers of these three aircraft evaluated by the Post Office, few apparent differences stands out between them. Even when looking at the three basic performance numbers of he speed, range and useful load, in figure 9, the numbers again are similar but two of the categories favor the Boeing Model 40 by slight margins.

12 6000

5000

4000

3000

2000

1000

0 Range Gross Empty Useful Speed mph miles Weight lbs Weight lbs Load lbs Boeing Model 40 113 700 5495 3425 2070 Douglas M-1 118 600 4775 2885 1690 Curtiss Carrier Piegon 105 525 5620 3603 2017

Boeing Model 40 Douglas M-1 Curtiss Carrier Piegon

Basic Performance Comparison 1925 Mailplanes Figure 9

For a while, during the evaluation period the Curtiss Carrier Pigeon seemed to be the front-runner of the three. (Leary, 1985) That changed when Post Office Pilot Arthur R. Smith left Chicago for Bryan, Ohio on the night of February 12, 1926. Shortly after 10 PM Smith crashed into the woods after hitting a tree near Montpelier, Ohio just six miles from Bryan. The crash was fatal for Smith. The cause of the accident was thought to be weather related even though there was a 1000-foot ceiling. (Leary 1985-p232). Most-likely, it was another case of low level flying in marginal weather condition at night. But as a result, Curtiss did not receive any follow on orders from the Post Office. Nor was the Boeing Airplane Company with their Model 40 prototype selected for additional orders.

The evaluative phase for the Post Office aircraft selection was largely informal and based mostly on pilot’s comments, input and pilot reports of Post Office pilots flying the prototypes on the mail routes.

Douglas Aircraft Company at the time had an excellent reputation in the aircraft industry with their military aircraft observation planes. Many of the Post Office pilots were Reserve Army Aviators and had flown the Douglas O-2B observation aircraft on which Douglas based their M-1 mailplane design. (Francillion, 1979). The Douglas M-1 mailplane also featured welcome innovations such as brakes and a tail wheel instead of a tail skid as on the other two aircraft (Leary 1985 - p232). The 1000lbs mail load could be carried at a cruise speed 118 mph while landing at 52 mph. Additionally, two of the four Douglas World Cruisers (DWC) had completed a around the World flight in 1924. The positive image of the

13 successful Around the World Flight reinforced the image of Douglas as an up and coming firm that designed and built excellent aircraft.

Based upon the recommendations from the mail pilots, the Postmaster General ordered 40 planes from Douglas Aircraft at $11,900 each. Later as the Air Mail Service was transitioning their routes to private contractors under the 1925 Air Mail Act (Kelly Act), it would order an additional 11 aircraft. (Leary 1985 - 233)

Boeing’s Design Approach

The Boeing Company of Seattle will have a hundred years of history in 2016. However, when it established itself as Pacific Aero Products on July 15, 1916 it was a small firm with only 21 employees. The named was changed on April 26, 1917 to Boeing Airplane Company and has been “Boeing” in one form or another ever since. (Bowers 1966 p34) From the end of World War I, in November of 1918, to the time of the design of the Model 40, Boeing managed to survive on aircraft modernization contracts for the government, that included the de Havilland DH-4 as describe previously, and building new airplanes designed by the Army Air Service Engineering Division based at McCook Field Dayton, Ohio. An example of the survival activity that Boeing was involved with was the GA-1 project. Boeing was the successful bidder to build to 20 (later reduce to 10) Ground Attack -1 (GA-1) that the Army had designed. This aircraft design was based on the experience of World War I trench warfare. First flown in May of 1921 the GA-1 had many design issues that included being extremely overweight, with poor aerodynamics and engine cooling. Nevertheless Boeing delivered all 10 aircraft to the Army. The experience did provide Boeing the opportunity to learn production methods for aircraft assembly, engineering design processes for aircraft performance improvement methods which would pay dividend in the later 1920’s.

The first non-military airplane designed and built by Boeing since 1920 was the Model 40 prototype in response to the Post Offices request for bids to replace the DH-4 .On April 7, 1924 E.N. Gott President of the Boeing Airplane Company authorized the Chief Engineer Claire L. Egtvedt and his team to proceed with the planning to respond to the Post Office request along the lines discussed in a meeting the pervious day with Mr. William E. Boeing. (Boeing Historical Achieves 170-2)

14 Boeing Historical Archives Model 40 Profile and Frontal View Figure 10

The aircraft that was designed had conventional wooden spars and rib construction with fabric covering. The overall length of the wing span, for both the upper and lower wings, was 44’ 2.25” inches. The wing span dimensions would remain unchanged with all subsequent Model 40s. The Fuselage length as seen in the profile drawing (figure 10) was 33’2.25”. The fuselage used laminated veneer wood over wood formers when at the time aircraft designers including Boeing were converting to steel tubing for the fuselage structures. Why Boeing selected this method of construction over steel can only be speculated since no document has surfaced at this time. I would assume it was a matter of the time and cost to build welding jigs when they had skilled resources to design and build the wooden structure prototype to meet the Post Office deadline. Later in 1932 a Boeing production manager remarked it cost three times as much to build a metal aircraft as a wooden one.

15

The wood veneer covering the fuselage had the grain running at a 45 degree angle to the axis of the fuselage as seen in figure 11a and 11b below.

Boeing Historical Archives Model 40 Wood Veneer Covered Fuselage (11a)

Boeing Historical Archives Veneer Fuselage of Model 40 with Liberty Engine (11b) Figure 11

There was also an unusual feature with the upper wing configuration. The right wing fastened to the cabane struts above the fuselage, but projected slightly to the left of centerline to the point where the left wing joined the right. (Bower 1989 p125) This offset can be clearly seen in the drawing of the Model 40B. (Figure 19).

There were four ailerons, all without balance in each wing. With the upper and lower ailerons connected by a pair or wires. The Model 40 made its first flight on

16 July 7, 1925. Flight test determined that the fuselage was a little short for directional stability. A modification was engineered to lengthen the fuselage to correct the problem by adding a steel frame extension at the tail. In figure 12 a, b and c below one can readily see the effects of this modification on the Model 40 prototype appearance.

Boeing Historical Archives

Profile Model 40 prior to Fuselage Extension (12a)

Boeing Historical Archives

Boeing Historical Archives Model 40 Fuselage extension Model 40 Fuselage extension modification (12b)

17 Boeing Historical Archives

Profile Model 40 with Rear Fuselage extension Covered (12c) Figure 12

Post Office records show the Boeing Model 40 (Boeing C/n: 775) was purchased and put into service February 10, 1926 on the Cleveland–Chicago route. (Boeing Historical Archives - file 604) The flight performance seemed to be satisfactory and was reported as such by a Post Office Pilot flight report filed by C. Eugene Johnson to F. E. Caldwell Acting Superintend of the Western Division route on February 26, 1926. (Boeing Historical Archives Post Office Letter Dated February 26, 1926)

Johnson documented his impressions on a flight from Concord California to Maywood Illinois prior to putting the Model 40 into service on the Cleveland – Chicago route. He reported on the taxing, take-off, landing, stability, maneuverability and visibility charteristics of the Model 40. Johnson reported mostly positive comments with the exception being the visibility. He said, “This could be improved and most of the fault lies in arrangement of the windshield, size and shape of pit opening (cockpit). At present, it takes considerable straining and stretching for “hedge-hopping” work, of which was done through Illinois.” (Boeing Historical Archives Post Office Letter Dated February 26, 1926)

What is telling about the comment Johnson made is the type of flying that was being done along the mail routes especially with poor visibility due to adverse weather. That in itself was a major factor contributing to the death of 32 of the original 40 Post Office pilot having fatal accident while flying the mail. Obviously, visibility was a major safety concern but flying low was not the solution.

However, the mechanical performance of the Model 40 did not receive favorable reports either. Apparently the cooling radiator for the Liberty 12 engine had several leaks. In over 187 hours of operation between February 26 and June 20, 1926 the Model 40 had to be taken off the line 10 times for repairs. Additionally, several large cracks and splits in the veneer fuselage were found during inspections. They revealed that the cracks, splits and tears were mainly localized

18 about the two front upper fittings which, with corresponding lower fittings supported the engine nacelle where they received loads due the reaction of the propeller torque, (twisting force) the thrust of propeller and the weight of the engine. The impacts from landing also contributed to the; cracks by the forces gear being transmitted through the gear, fuselage and engine mounts.(Figure 13) The result of this inspection determined the Model 40 had to be withdrawn from service on June 22, 1926 until modification and repairs were made. (Boeing Historical Archives Post Office Letter Dated July 20, 1926) This added to the factors why the Model 40 was not considered for a follow on orders from the Post Office at the conclusion of their evaluation period, when orders were placed for the Douglas Mailplane.

Boeing Historical Archives Area which fuselage cracks appeared on Model 40 Figure 13

Although, the Boeing Airplane Company did not win the initial competition for the D.H. 4 it was not the end of the Boeing Model 40. The following will describe the Model 40 rebirth and engineering along with the contribution it made towards facilitating corporate aviation growth in the turbulent years ahead.

Establishing the Industry

Events leading to Boeing Model 40 redesign

With the announcement that the Douglas M-1 mailplane was the winner of the Post Office contract to replace the Department’s aircraft and Douglas Aircraft would receive follow-on orders for additional planes. Boeing filed away all of their design drawings, not realizing they would be pulled from the file within 18 months to re-engineer the Model 40 mailplane. The Boeing Airplane Company would

19 redesign the aircraft in order to submit a bid for the Chicago to San Francisco portion of the transcontinental air mail line.

Since the Wright Brother’s developed and publicly demonstrated the first practical aircraft to the U.S Army at Fort Myers Virgin (Orville) and Le Mans France (Wilbur) in 1908 it is strange the United States should lag so far behind other countries aviation industries prior to and after World War I. After the Great War three main elements in the United States kept the aircraft industry alive and in front of the public. The three were the Military, with demonstration flights, such as, the Navy’s 1919 NC flights across the Atlantic and the Army’s 1924 around the World Flight with two of the four Douglas World Cruisers completing the attempt. The second were the Barnstormers who with surplus aircraft from the war gave thousands of Americans their introduction to going aloft. And finally the Post Office with the successful effort of establishing the transcontinental air mail line.

However, none of these had any established infrastructure, regulations or standard operating procedures guiding them prior to the United States entering World War I. The National Advisory Committee for Aeronautics (NACA) was established on March 3, 1915. Although the NACA rapidly became an independent agency little was accomplished due to public and government apathy toward the aviation industry. Shortly after the World War I President Wilson submitted a Bill to Congress drafted by the NACA that would authorize the Department of Commerce to license pilot, Inspect aircraft and operate aerodromes (airports) but the apathy continued and no legislation was passed. In the interim 26 States passed what was to be called the Uniform Aeronautics Act which was regulatory in nature but hardly uniform and rarely enforced. (Hallion, 1977)

Ironically it would be the railroad industry that would be the catalyst that accelerated the legislation and infrastructure so badly needed in aviation to move beyond the level of a hand to mouth aircraft industry. As airmail began crossing the country successfully in the mid-1920s, railroad owners started complaining that the government-sponsored enterprise was cutting into their business. They found a friendly ear in Congressman Clyde Kelly of Pennsylvania, chairman of the House Post Office Committee, who largely represented railroad interests. On February 2, 1925, he sponsored H.R. 7064: the Contract Air Mail Bill, which, when enacted, became the Air Mail Act of 1925 or the Kelly Act as it became known. The act authorized the postmaster general to contract for domestic airmail service with commercial air carriers. It also set airmail rates and the level of cash subsidies to be paid to companies that carried the mail. As Kelly explained: The act “permits the expansion of the air mail service without burden upon the taxpayers….” By transferring airmail operations to private companies, the government would help create the commercial aviation industry.

20 Eighty percent of the stamp money received by the Post Office was to be paid to the civilian airmail carriers. The quantity of stamps needed depended on the weight of the mail and also on how many of the three zones the mail had to cross. (The country had been divided into three air zones on July 1, 1924.) Companies saw that they would make more money if they carried smaller but heavier pieces of mail. This led to some unethical practices, like the shipment of phone books by friends of the contractors. Also, since they would receive the same amount of money no matter how many miles they flew within a zone, they preferred to fly shorter distances within a single zone and save some operating costs. (Davies 1998)

Harry S. New, postmaster general under President Calvin Coolidge wanted the new contract airmail carriers to expand their routes and to buy larger airplanes to carry passengers. He awarded contracts only to the larger companies that bought the largest aircraft, which could accommodate passengers as well as the mail. New realized that if the airlines sold more passenger tickets, which then numbered only a few hundred each year, they could carry less mail and still make a profit. The companies would receive their income from paying passengers rather than from the Post Office payment for carrying the mail. Post Master New started by awarding eight airmail routes to seven airmail carriers, beginning in October 1925. One carrier, Ford Air Transport, won two of the routes and was the first to fly airmail carrier under contract, starting on February 15, 1926 (figure 14) (www.centennialofflight.gov/essay/Government_Role/1925- 29_airmail/POL5.htm)

First Contract Mail Routes Awarded to Civilian Contract 1926 Figure 14

With the passing of the 1925 Air Mail Act Congress moved rapidly with the passing of the Air Commerce Act in May of 1926. For the first time this gave the U.S. Government responsibility for fostering air commerce, establishing airways and aids to air navigation, making and enforcing safety rules. Under this act, the government supplied money for air navigation facilities so that the routes would become safer to fly, day and night. Management of the route system moved to the new Aeronautics Branch of the Department of Commerce, which was established in August of 1926. This act also set the standards for levels and types of pilot license, mechanics certification to maintain aircraft, airmen’s medicals and the government certification of U.S. Civil aircraft.

21 Both these pieces of government legislation would have far reaching impacts not only to the aviation industry but also the Boeing Company and the redesigned Boeing Model 40.

The Post Office began the transition of its routes to private contractor in April of 1926 and was completed in August of 1927. They started with the routes that feed into the main transcontinental line but in late 1926 the Post Office asked for bids for two main portions of the transcontinental line. The two bids would be submitted for either the San Francisco–Chicago route or the Chicago–New York route which would be transferred to the bid winners on July 1 1927. The Post Office wanted to guard against the possibility of one operator going out of business after contract award and shutting the air mail system down for an extended period of time. The Post Office felt no one operator had the planning and logistical experience to operate the entire transcontinental air line starting out of the gate as a new operator.

Apparently William E. Boeing Chairman of the Boeing Company whose post war employment was at an all time high of 602 employee in 1926 gave little if any initial thought to submitting a bid to the Post Office for either one of the longer transcontinental air mail route segments. However, as in all key moments in history fate was to intervene.

Eddie Hubbard, a well known local Northwest Pilot who had worked for Boeing in the past completed along with William Boeing the world’s first international airmail flight into the United States from Vancouver B.C. to Seattle Washington on March 3 1919. (Brown 1996). Hubbard would leave Boeing’s employment and go on to fly the mail and charters for fishermen going to remote lakes throughout the Northwest. Hubbard used the first Boeing commercially design and built aircraft as seen in figure 15. This was the Boeing B-1 (model 6) (Bowers 1989 p49). Hubbard also worked for short period of time in California to take advantage of expanding flying opportunities. However, he remained friends with William E. Boeing and Boeing’s then President Philip Johnson and Chief Engineer Claire Egtvedt.

22 Boeing Historical Archives

Boeing’s First Civilian Aircraft Model B-1

Figure 15

In November of 1926 when the Post Office had announced plans to put its Chicago–San Francisco airmail route up for bids Hubbard returned from California to meet with Boeing’s Johnson and Egtvedt. Hubbard had a concept in mind based on his experience flying mail and passengers between Seattle and Vancouver B.C. Since Johnson was away from the office he met with Claire Egtvedt. In the parlance of today’s vernacular Hubbard presented “a business case” to Egtvedt for the successful operations on the San Francisco - Chicago airmail route. Hubbard had estimated his return on investment (ROI) on day/night operations, miles flown and pounds of mail carried. During the meeting it was suggested by Egtvedt that Boeing re-engineer the Boeing Model 40 Mailplane using the newly design Pratt & Whitney Wasp 420 H.P. air-cooled engine. With the air cooled engine it would be feasible to be successful especially with an aircraft on a long route. After further refining their estimates they met with William E. Boeing for his thoughts and input. Boeing by nature was a conservative person who based his success in his many business endeavors on thoroughly analyzing the risk involved with the opportunities presented. He did not say no to Hubbard and Egtvedt when they first met but thought about the possibility over night. The next day he came to the plant to go over the figures once again. The Post Office would allow the winner of the bid up to $3.00 per pound for the first 1,000 miles and fifteen cent for each additional 100 miles (Bauer 2006 - p37).

Based on the expected performance of the re-engineered Model 40 with the Pratt & Whitney Wasp engine William Boeing felt the numbers the team put together were realistic and then had his team prepare a bid proposal of $2.88 for a pound of mail carried between San Francisco and Chicago. This bid proposal was submitted to the Post Office by the due date of January 15, 1927.

The reason Eddie Hubbard, William Boeing and the Boeing engineering staff felt confident they could be successful with the bid proposal submitted was their familiarity with the relatively new power plant designed and developed by the

23 recently formed company called Pratt & Whitney Aircraft Company of East Hartford, Connecticut.

The Pratt & Whitney Aircraft Company

Frederick Rentschler had resigned as president of the Wright Aeronautical Corporation on September 21, 1924. When the Wright Company was looking into the possibility of the radial engine they examined a possible merger with the Lawrance Engine Company who had been one of the pioneers working on the air cooled engine concept since 1921. Rentschler after studying the Lawrance Company operations and engine designs advised his board against such an acquisition. In his own words “a completely confused manufacturing operation”. (Pratt & Whitney 1950 p28). From that point on Rentschler had difficulty with the Wright Aeronautical Board, made up mostly of bankers owning little stock in the Wright Company who only wanted immediate return on investment (ROI) rather than longer research and development efforts for the possibility of greater ROI.

When he departed Wright Aeronautical, Rentschler sought the advice of another industry icon, Chance Vought, Rentschler told Vought of his plan to create an organization where management and engineering drove the organization. Rentschler laid out a plan of what such an organization would look like in order to design and develop an air-cooled radial engine capable of 400 plus horse power with as many modern features as possible. (Pratt & Whitney 1950 p32). After listening to Rentschler’s proposal Vought urged him on to look for backers for his concept and plan. So six month after resigning from Wright Aeronautical Rentschler went to see the Pratt & Whitney division of the Niles-Bement-Pond a machine tool company of Hartford Connecticut. He asked them for $425,000 to build a prototype engine. With his past experience and reputation in the aircraft industry, especially with engines Bement-Pond accepted the proposition.

On July 23, 1925 Pratt & Whitney Aircraft was incorporated with Rentschler president, George Mead vice president and Andy Willgoos chief engineer. Mead and Willgoos had both left Wright Aeronautical to joined Rentshler at Pratt & Whitney. They and those they hired worked around the clock on the new design and manufacturing processes of their prototype air cooled radial engine. Their only numerical goals was to develop 400 H.P. within a weight of 650lbs. December 29, 1925 they started the engine for the fist time and within in a few days it was delivering 425 H.P. within the 650lbs limit. The Pratt & Whitney Wasp engine was born. (figure16)

24

Pratt & Whitney 1926 Wasp Figure 16

The first engine was a test stand engine that never flew but the second engine became airborne powering a Wright FeW-1 Apache flown on May 5, 1926 by Navy Lieutenant C.C. Champion Jr.

The flight test results were dramatic in terms of performance and reliability. Pratt & Whitney Wasp engines were installed in short order into Curtiss, Vought and Boeing Aircraft. And that is why Claire E Egtvedt thought the Pratt & Whitney engine would be the right selection for the re-engineered Boeing Model 40 when he initially talked with Eddie Hubbard in November of 1926. The Boeing Company had been working with the Navy testing the new Pratt & Whitney Wasp Engine on the Boeing Model 69 (XF2B-1) (figure 17). This aircraft would go into production as the Navy F2B-1. However, at the time the Boeing Company submitted their bid proposal to the Post Office for the re-engineered Model 40 no production Navy F2B-1 had been constructed yet.

Boeing Model 69 (F2B-1) with New Pratt & Whitney Wasp Figure 17

25 But Boeing would have a supply of Wasp engines on hand for the 32 F2B they were going to build as soon as funding was approved. (Bower PNAHF Journal Vol. 8).

The other main bidders for the Chicago – San Francisco route were Western Air Express and National Air Transport. Both were experienced well financed airline operators already flying shorter contract mail routes. Western Air Express had an excellent reputation of flying the Liberty powered Douglas M-2 (figure 8) mailplanes across the mountainous country between Los Angels and Salt Lake City while National Air Transport had six Curtiss Carrier Pigeon, (figure 7) also Liberty powered built specially for the use on Chicago – New York portion of the route. When the bids were open and evaluated by the Post Office in the latter half of January 1927 the Boeing bid was the lowest coming in at $2.88 per pound of mail for the whole journey. This beat by a substantial margin the next closest bidder, Western Air Express, that was $4.25 (Davies 1972 p59). The advantage of using the relatively new technology Pratt & Whitney air-cooled engine allowed Boeing to bid at the unprecedented low bid. The engine weighing 200 pounds less than the older Liberty translated into passenger capability as well as more mail that could be carried. As William E. Boeing told anyone who would listen. “I would rather fly 200 more pounds mail than water”. (Pratt & Whitney 1950) After winning the contract on January 29, 1927 the Post Office required an insurance performance bond. The Post Master was reacting to other competitor companies telling him the mail could not be carried for such a low cost as Boeing submitted. William Boeing personally wrote a $500,000 bond so the Boeing Organization could continue with its’ plan to operate an airline. (AAHS Journal Vol. 49 - P114) On February 17, 1927 Boeing Air Transportation was incorporated.

Bringing the Boeing Model 40A to Production

Key Events and Activities

Now the Boeing team had five main challenges; (1) to complete the redesign of original Model 40 prototype, (2) acquire enough Pratt & Whitney Wasp engine to produce 25 Model 40A’s with spares, (3) hire the personnel to fly and maintain the new aircraft along the route (4) be ready to begin operations along the entire route in six-months starting July 1, 1927. (5) comply with the new airworthy standard set forth in the recently passed legislation called the “Air Commerce Act of 1926”. This legislation was signed into law by President Calvin Coolidge on May 26, 1926. (van der Linden 2002) This act effectively established the first regulations in the United States for the certification of airmen, airways and aircraft. The Air Commerce Act created an Aeronautics Branch charged with the promotion and regulations marking the beginning of civil aviation oversight in the United States. (Emme, Hallion, Two Hundred Years of Flight in America, 1976 p158) This would also be a learning curve since no manufacture had gone through the “Aircraft Type Certification” (A.T.C.) process which now had to be

26 followed and complied with under the Act. The Boeing Model 40A would only be the second aircraft to do so when it received A.T.C. #2 in July 1927.

Eddie Hubbard went off to Salt Lake City, the city where three of the five exiting air mail routes came together. It was an excellent location to hire personnel for the new Boeing airline operation. The first 21 pilots came from the Post Office Air Mail Service. All of them had many hours of experience flying the mail for the Post Office. (AAHS Journal Vol. 49 - P114) This would be a real plus for many reasons especially when it came to attracting passengers by highlighting the experience of the line’s pilots.

In the mean time William Boeing himself was instrumental in securing the needed and critical Pratt & Whitney Wasp engines for the Model 40A’s. Fred Rentschler and William Boeing had become friends (Figure 18) when the Wasp engine was mated to the Navy F2B-1 Fighter. The Boeing Company was contracted to build 32 for the Navy. Unfortunately, all the Wasp engines had been committed to the F2B contract therefore making it impossible to obtain the new engine commercially for at least a year. However, William Boeing through his friendship with Rentschler was able to arrange with the Navy to release Wasp engines to the Boeing Model 40A project with an assurance from Rentschler that replacements Wasp would be available when needed for the Navy F2B-1 contract. (Bower -1966 p116).

Through this collaboration with Pratt & Whitney’s Rentschler, William Boeing, the Boeing engineering staff and production personnel would have the needed numbers of Wasp engines required for the Model 40A. (figure 18)

Boeing Historical Archives Boeing and Rentschler inspect Wasp Figure 18

Here is an interesting speculation, “What if Boeing and Rentschler hadn’t had the friendship they had, how would that have affected the course of Boeing History”? However, what did occur because of Rentschler’s arranging an agreement with

27 the Navy Bureau of Aeronautics was that the Boeing Airplane Company would begin receiving 5 Wasp engines per month beginning in February 1927. In addition, they would receive 3 extras spare engines for a total of 28 when flight operations began on July 1, 1927.

The Boeing engineering team under Egtvedt had been working on the redesign of the Model 40A with the possibility of the Pratt & Whitney Wasp engine even before initial discussion with Eddie Hubbard in November of 1926.

At first glance when one compares the specification and performance numbers between the original Model 40 and the new Model 40A using the Pratt & Whitney Wasp there appears to be little apparent difference (Figure 19 a & b).

Boeing Historical Archives

Model 40 Redesign with P&W Engine

Figure 19

28

Aircraft Boeing Model 40 Boeing Model 40A First Flight 7-July 1925 6-June-1927 # Produced Prototype 25 Pilot / 2 Optional Pilot & Pax Pilot Only Pax Powerplant Liberty 400 h.p. P&W 420 h.p. Wing Span 44'2" 44'2" Length 33'2" 33'2" Height 12'3" 12'3" Empty Weight 3,425 lbs 3,531 lbs Gross Weight 5,495 lbs 6,000 lbs. Speed 135 m.p.h 128 m.p.h. Range 700 miles 650 miles ceiling 15,800' 14,500' Boeing Model 40 and 40A Comparison Figure 19a

7000 6000 5000 4000 3000 2000 1000 0 Gross Empty Speed Range Useful Engine Weight Weight mph miles Load lbs HP lbs lbs

113 700 5495 3425 2070 400 Boeing Model 40 105 650 6000 3531 2469 420 Boeing Model 40A Boeing Model 40B-2 105 650 6000 3531 2469 525

Boeing Model 40B-4 125 535 6075 3722 2353 525

Boeing ModelModel 40 Boeing40s Summary Model 40A BoeingPerformance Model 40B-2 ChartBoeing Model 40B-4

Figure 19b

However, due to the 200 lbs. reduced weight of the Pratt & Whitney air-cooled engine verses the older Liberty 12 engine which translated into increased payload not only in mail but allowed for two passenger to fly the route to generate additional income above the mail contract compensation. This plus the added benefit of the Wasp engines increase in reliability allowed Boeing to submit their relatively low bid when compared to the others in the competition.

From a dimension point of view the two Model 40’s were identical. The wing construction on both used spruce and ribs with fabric covering a six foot seven inch Clark “Y” airfoil (figure 20). This airfoil would suit the operational

29 requirements for the high altitude because of with its good high lift flight chacteristics. The inter-plane struts on the Model 40A eliminated the wooden diagonal braces between the main forward and aft members that were on the Model 40. They were replaced with heavy flying wire bracing on the 40A.

Boeing Model 40 Clark “Y” Airfoil 6’ 7”

Figure 20

The Model 40A fuselage structure was also completely different than the Model 40. As seen in figure 21 the fuselage structure was welded tubular steel rather than the wood veneer fuselage of the prototype Model 40.

Boeing Historical Archives

Boeing Model 40A Steel Truss Fuselage Figure 21

The steel truss airframe was built up with non-load bearing wood stringers that provided the rounded and streamline shape to the fuselage before being covered with cotton fabric and sections of dural aluminum sheet metal.

30 420 hp Wasp Engine Front baggage bin 25 cu.ft. Passenger compartment

Aft mail bin 37 cu.ft.

Pilot Cockpit Boeing Historical Archives

Boeing Historical Archives Boeing HistoricalBoeing ArchivesHistorical Archives

Boeing Model 40A Fuselage Configuration Figure 22

Figure 22 shows the airframe configuration for the pilot, two passengers, mail and baggage bins. This arrangement provided the aircraft a great deal of flexibility for load and management of the center of gravity for weight and balance purposes. On the Model 40A there is a passenger door on each side of the fuselage. The passenger cabin area was metal lined throughout with the seat covered in leather. (figure 23) An airspeed indicator along with an altimeter was also located in the cabin. The non-shattering glass window could be open in flight and was large enough to provide excellent view of the scenery. A dome light could provide limited light at night. A 100 gallon fuel tank was provided just behind the aft mail bin. This configuration would change in subsequent Model 40’s to using three different fuel tanks. The Model 40B would have one forty gallon tank located in the upper right center section with other two located on the right and left side lower wing root area.

Model 40A Two Passenger Compartment Figure 23

31

The Model 40B-4 andBoeing Model Historical 40C Archives would have the same configuration. However, the upper wing tank had a capacity of 60 gallons. Figure 24 shows schematically arrangement which was basically the same on all Model 40 versions after the Model 40A.

New Model 40 Fuel System - After the Model 40A Figure 24

32 Mounted Night Lights

Mixture & Rudder Bar Throttle Fuel Tank Selector

Boeing Historical Archives

Model 40A Pilots Cockpit Figure 25

The cockpit was fairly typical for its day. The mixture and throttle controls were on the left side with the standard flight instrument that included altimeter and turn and bank. Cockpit lights were also standard to illuminate the instruments during night operations. (figure 25). The landing gear used the new air-oleo strut of Boeing design.

The overall redesign of the Model 40A was strong, functional and producible. All these attributes would be important for the operational success of the aircraft while flying the Contract Air Mail (CAM) Route #18 from San Francisco to Chicago.

The Boeing Seattle factory had to build and certify twenty-five planes and then test fly them in less than five months. To add to this challenge when the aircraft were completed (figure 26) they had to be trucked 15 miles away from the Boeing factory to Sand Point located north and east of factory on Lake Washington because Boeing did not have a long enough runway near the factory. At Sand Point a pasture was cleared among the pines to serve as the needed runway. This location also served as, King County Airport until 1928 when Boeing Field formally opened. (figure 27)

33 Boeing Historical Archives Completed Boeing Model 40A Figure 26

Boeing Historical Archives Sand Point Testing Location Figure 27

From contract award in February 1927 to being operationally ready on July 1, 1927 it was an all out effort for the Boeing team. When Pratt & Whitney sent Wilbur Thomas one of its early service representatives to support Boeing he was shocked and concerned how much there was left to do. Arriving on June 1st 1927 Thomas found only one aircraft completed. (Pratt & Whitney 1950) From that point on one plane per day seemed to be completed. Then immediately after a short test flight the aircraft was flown off points along the route. By midnight June 30th all 25 Model 40As were in place along CAM #18 to begin operations the next day as per the contract. Ever 24 hours the new model 40A’s with their Wasp engines would cover 4000 miles on the round trips between San Francisco and Chicago.

34 The Boeing Model 40 - Transcontinental Line Operations

Boeing Air Transport began air mail service as scheduled on July 1, 1927 from San Francisco’s Crissy Field. The day before Mrs. Bertha Boeing, William Boeing’s wife, sitting on the right side of the platform (figure 28) between two gentlemen christened the inaugural Model 40A aircraft “City of San Francisco”.

Boeing Historical Archives Inauguration Day Boeing Air Transport - Crissy Field Figure 28

The next day at the other end of the line in Chicago Boeing Air Transport (BAT) boarded their first passenger on a Model 40A. A reporter from the Chicago Herald Examiner Jane Eads took off at 9:30 PM with former Post Office Pilot Ira Biffle now working for BAT and they headed west bound. As the trip progressed west Eads gave positive reports and statements to the media, such as, “I could fly forever”. (Bauer 2006 p 39) Eads completed her trip after 23 hours of flying time and BAT was officially in the business of both flying the mail and passengers.

Due to terrain, weather conditions and a lack of navigational land marks it would have been hard to find a more challenging route to begin operations. As figure 29 illustrates the Midwestern section of the route between Iowa City and Omaha looks like it could be flown with deceptive ease.

35

Figure 29

However, from North Platte a long steady climb to Cheyenne was begun flying westbound as the route penetrated the Rockies Mountains to Rock Springs. After topping the saw-toothed Wasatch Mountain Range at 7000 feet it was a descent to the hot salt flats of Salt Lake City. From Salt Lake to San Francisco there was more mountain high country between Elko and Reno before another major ascent over the Sierra Nevada’s finally descending down into the Sacramento Valley and landing at the Oakland Municipal Airport. The eastbound was just as rigorous with a maximum climb to Reno and not descending until after Cheyenne.

The schedule route time from Chicago was approximately 20 flying hours plus. Passengers who would follow Jane Eads would pay $200 one way to ride in rather confined by enclosed passenger compartment in front of the pilot (figure 24). Choosing this method of transportation BAT passengers found they had taken 43 hours off the enroute time compared to taking the train between the two cities of Chicago and San Francisco. (Davis 1982).

With mail and passenger operations now becoming a daily event the Pratt and Whitney Wasps engines were proving themselves in the field. After some minor overheating problem during the first two weeks of operations they became incredibly reliable passing the then standard 200 hours of operation before overhaul. The reliability of the engine and the paying passenger carried in the

36 Model 40A allowed Boeing Air Transport to astound its critics and make a profit during the first year of operations. (Davis 1982, p60). The inaugural year saw BAT fly a million and half miles over the route. At the end of two years they had flown 5,500,000 miles while delivering 1300 tons of mail and 6000 passengers. The 24 months of initial flight operations was also accomplished with a good safety record for the time. Only three fatalities were recorded for an average of one for every 1,750,000 miles flown. These types of metrics helped to sell the idea of air travel not just to the adventurer but to the general public and business professionals as well. This positive response was helped in no small measure by the effects of Charles A. Lindbergh’s successful flight from New York to Paris on 27 May 1927. This not only sparked people’s imagination to the possibility of air transportation but it facilitated financiers to the investment potential of the aviation industry. It seemed like almost over night everyone wanted to become involved with the aviation industry. Pilot starts increased dramatically with more Research and Development (R&D) money becoming available from government, foundations and industry for the development of aircraft and aircraft support functions, including the development of those items listed in figure 30. These examples of R&D projects had begun at a slow pace in mid 1920’s became a rapid evolution during the decade of the 1930’s. (Whitford, 2007)

1924 -1929 AIRCRAFT TECHNICAL DEVELOPMENTS

•RADIAL ENGINES •DRAG REDUCTION •AIRCRAFT STRUCTURAL IMPROVEMENTS •WING FLAPS •RETRACTABLE LANDING GEAR •INSTRUMENTATION •AIRCRAFT SYSTEM

Figure 30

Aviation and technology historian John Anderson would identify this era in chapter 6 of his book “The Airplane, A History of the Its Technology” as “The Era of the Mature Propeller-Driven Airplane”. The Boeing Model 40A which from a new aircraft technology point of view was at the back end of an old aircraft design concepts was however, with the Pratt & Whitney Wasp radial air cooled engine, at the front end of the rapidly developing industry change. The Model 40A made it possible for the Boeing Company to be in the right place to participate in this growth. Shortly after the Model 40A made its introduction with BAT another Pratt & Whitney engine with more horsepower was being developed for the higher

37 altitude landing fields along the route, especially west of Cheyenne. This engine was called the Hornet. The design began in January of 1926, making its’ first flight in June of the same year. The new air cooled radial engine offered 525 hp, an increase of 105 horse power over the Wasp engine of 420hp.

Although Boeing Air Transport had a separate identity from the parent Boeing Airplane Company BAT was managed from Seattle. With the positive results they were achieving on their section of the transcontinental line (CAM #18) Boeing management made two major decisions in 1928. One they would convert most of their Model 40 A’s to the new Pratt & Whitney 525 hp Hornet engine. With this change to the Model 40A they would become Model 40B’s. On a rotational schedule they were flown back to the factory in Seattle for the engine change then back to flying the line. However, since this engine change altered the Model 40A’s gross weight to 6075lbs along with other flight performance numbers it had to be re-certified; on February 1928 ACT #27 was awarded making those Model 40As Model 40Bs. The other major decision was made on January 1, 1928 when Boeing Air Transport acquired control of Pacific Air Transport (PAT). PAT was a contract air mail carrier on CAM #8 which paralleled the west coast form Seattle to San Francisco. The acquisition provided a direct link from the Boeing Seattle factory to the western end of the transcontinental route in San Francisco, as well as, a market for additional Boeing transports. In May of 1928 Pacific Air transport began operating six Boeing 40Bs. (Davies 1982 p70). This merger also necessitated a name change to “The Boeing System” for the combined lines.

Logo Change for combined Boeing System Line Figure 31

Boeing Historical Archives 38 Figure 31 shows the revision made to the logo to accommodate the merger of the two lines. On the former PAT route the words AIR TRANSPORT, INC were removed from the circle and replaced by the single SYSTEM, while the words PACIFIC AIR TRANSPORT were painted on a straight line flanking the logo. The original logo was retained for the Boeing Air Transportation routes. (Bower 1966 P117) Boeing management in Seattle continued to oversee and provide strategic decision making for both lines in the “SYSTEM”. As reported in United Aircraft & Transport Corporation’s first annual report to stockholders in 1929 the two transport companies completed flying 8 million miles in December of that year and at the time were considered to be the most efficiently operated mail-passenger lines in the United States. (1929 UATC Annual report p 41)

The re-engineered Boeing Model 40 was making it possible for the Boeing Company to fulfill its original charter to "To engage in the business of aerial navigation by any means whatsoever, heretofore or hereafter invented or developed, including also to act as a common carrier of passengers and freight by aerial navigation..." (Boeing Historical Archives- Articles of incorporation Pacific Aero Products 1916) From this point on expansion and opportunity would continue at a rapid pace for the Boeing Airplane Company.

United Aircraft and Transportation Corporation

Some air mail contract operators didn’t believe the passenger business would ever be profitable. They felt the money spent for marketing to a potential passenger was money thrown away. When passenger did show up for a flight the mail bags were often treated better. What the operators wanted was a faster aircraft that could carry heavier payloads than the existing aircraft on flying the line.

William E. Boeing and Fred Rentschler had another concept in mind. Why not increase passenger revenues on top of the air mail contract revenues. Bigger and faster aircraft were needed but carrying more passengers in better comfort seemed to have a greater potential. Rentschler who like working with Boeing on the Model 40’s production and the results they were achieved suggested that they form a partnership between their two organizations which could capitalize on their mutual strengths in the commercial aviation market. From these initial discussions several mergers were consummated in late 1928 into 1929 between The Boeing Company, Pratt & Whitney and other aviation companies. These merger agreements lead to the formation of United Aircraft and Transportation Corporation on February 1, 1929. It was a holding Company whose original members included Pratt & Whitney Engines; Boeing Airplane Company; Chance Vought; and Hamilton Aircraft Propeller. A short time

39 later Standard Propeller, and the Stearman Aircraft Corporation were added to the engineering and manufacturing companies. On the air transport side of the organization, National Air Transport which now flew routes from Dallas Texas to New York via Chicago along with Varney Air Lines whose route ran from Reno, Nevada to Pasco Washington via Boise Idaho were added to Boeing Air Transport and Pacific Air Transport Line. As a result of the increase in air transportation routes and activity a new management company was formed to handle the growth and the “Boeing System” became United Air Lines. (Pratt & Whitney p73) The United Aircraft and Transport Corporation Model 40’s were now flying the transcontinental line. (Figure 32)

Boeing Historical Archives

Boeing Model 40A Air Transport with after the fact Photo touch up with United Airline Marking. No actual Model 40A had this logo Figure 32

With $146,000,000 of total capital between the Equipment and Transport Companies this formed a formable aviation conglomerate as can be seen from the scope of the organization chart for UATC in figure 33 below.

By 1929 BAT was operating 46 aircraft on the line, many of which were Model 40 B-2s and 40B-4s (four passengers Model 40bs).

.

40

Figure 33

The Organizations listed under United Aircraft & Transport Corporation in their 1929 Annual Report to Stockholders were:

• Equipment Companies o The Boeing Airplane Company o `Boeing Aircraft of Canada, Ltd. o The Hamilton Standard Propeller Corporation o Northrop Aircraft Corporation, Ltd. o The Pratt & Whitney Aircraft Company o Canadian Pratt & Whitney Aircraft Co., Ltd. o Sikorsky Aviation Corporation o The Stearman Aircraft Company o Chance Vought Corporation • Transport Companies o Boeing Air Transport, Inc.- Pacific Air Transport o Stout Air Lines • Other Operations o Boeing School of Aeronautics o United Aircraft Exports, Inc. o United Airport Company of California, Ltd. o United Airports of Connecticut, Incorporated

41 The headquarters for UATC organization was located in East Hartford Connecticut with Fred Rentschler as President and William Boeing as Chairman of the Board. The timing for the formation of UATC could not have had happened at better time because by the late 1920’s other groups were forming large aviation corporations as well North American Aviation, which acquired the Curtiss-Wright Corporation. The auto manufacture, General Motors, got into the mix as well by acquiring Western Air Express. Aviation was now big business and the financiers wanted to get into the act by bringing competition into the industry with additional mergers.

The UATC companies were now in a position to deal with the increased competition growing in the commercial aircraft market place from these other mergers. Additionally, many companies that were part of UATC were able to survive the trouble ahead when the stock market and world economy suffered a depression starting in November 1929. However, before the reality of that became evident the Boeing Model 40 which initially brought Boeing and Pratt & Whitney together was constantly being modified and improved during the merger and acquisition process that formed UATC.

The strength of UATC was the rich talent of the combined companies engineering and production staffs. They formed a technical advisory committee for the purpose of interchanging of ideas, unity of efforts and making available the benefits of research to all.

This would improve and accelerate aircraft design while enhancing safety improvements for flight operations.

One example of this type collaborative effort in R&D was led by Boeing’s Thorp Hiscock. (figure 34) He suggested that radioing updated weather information to pilots en route could eliminate some of the uncertainty, and then offered to solve the problem. With approval from the Boeing Airplane Company, he began experimenting with low-frequency radio transmitters and receivers. Hiscock had radio receivers and transmitters installed in some Model 40s. He soon achieved what others before him had not: ground-to-air radio communication. This major break through step would help to tremendously improve flight safety by having pilots while in the air receive the most current weather and flight information

42

Boeing’s Thorp Hiscock Figure 34

How many were Built and What Model 40 is it

The following is a summary of the variations of the Model 40 built. As seen below in figure 35 the total number of Model 40s built was 82.

Model Year Built ATC Number Number Built

40 1925 Not Required 1

40A 1927 2 25

40B-4 1929-1931 183 39

40C 1928-1929 54 10

40X 1928 54 1

40Y 1928 183 1

Total U.S. Boeing Built 77

Non U.S. Boeing Canada

“40H-4 1929-1931 Non - U.S. 5

Total Boeing U.S. & Canada Model 40s 82

* Last Canadian Aircraft Msn CB-9 not Completed

Model 40 Production Numbers Figure 35

43 There has seems to be a bit of confusion over the total number of Model 40s built, with both 81 and 82 being documented.

Boeing has Manufacture Serial Number (Msn) Data Cards for each aircraft constructed going back to the original 1916 Boeing & Westervelt B&W bi- plane. Reviewing these Msn data cards show the total number of U.S. Boeing Model 40s built to be 77. However there were 5 Canadian built Model 40s built by Boeing Aircraft of Canada Ltd. In Vancouver, B.C.

Boeing also issues a Model Specification and History data sheet for each Boeing Commercial Aircraft. These sheets provide basic specifications and performance numbers for the aircraft model, as well as, numbers of that model built. In many cases the Boeing Model Specification and History data sheets list the Msn(s) for the Model as part of the references with in the context of Model Specification and History sheet information.

The Model 40B-4 Specification and History sheet has recorded 38 built with the Msn listed on page 3 of the sheet. However, Boeing Manufactures Serial Numbers issued for the Model 40B-4 (Msn) as recorded in their Msn Data Cards show 39 aircraft. The additional 40B-4 is Msn 1164 which Boeing identifies as a 40B-4A sold to Pratt & Whitney with a Pratt & Whitney 650 H.P. engine and a three bladed propeller.

Aviation Historian Walt Bohl in his excellent summary article on the Model 40s in the American Aviation Historical Society Journal (Summer 2004 volume 49 Number 2) list all the Model 40B-4 built by Msn.

Boeing Historical Archives

Four Passenger Model 40B-4 Figure 36

44

Bohl’s lists MSN 1164 for the Model 40B-4 not found on the Boeing Model Specification and History sheet. Bohl’s list also matches the Boeing MSN data cards for the Model 40B-4 found on file in the Boeing Archives.

The Msn listed in Bohl’s article and the Boeing Msn Data cards came to 39 Model 40B-4 in both counts. However, Bohl’s summary of the number of Model 40B-4 built at the end of his article shows 38 Model 40B-4s built Apparently, Bohl didn’t include MSN 1164 as a model 40B-4 in his final count or it was a miscount being recorded as 38 instead of 39 found in his article showing the list by Msn numbers.

This author has verified Bohl’s list of 39 with Msn Data Cards on file with the Boeing Historical Archives. The Model 40B-4 Msn that was listed in Bohl’s article and in the Boeing Msn Data Cards match including Msn 1164 delivered to Pratt & Whitney on October 10, 1929.

The Model designation for the Pratt & Whitney aircraft was Model 40B-4A. The information seems to confirm that 39 Model 40B-4s were built not 38 as previously reported in a variety of sources. This would bring the number of U.S. Boeing built Model 40’s to 77 and shown in figure 36.

However, the confusion doesn’t stop there. Another area of confusion was the number of Canadian Build Model 40’s. During the merger activity between1928-1929, Boeing established a factory in Vancouver, B.C. called Boeing Aircraft of Canada Ltd. They built 5 Model 40s confirmed by their Msn system. Their version of the Model 40B-4 was called the Model 40H-4. This was an aircraft basically the same as the Model 40B-4. The “H” in the Model designation was used to honor the Boeing Canadian Company President Henry Hoffar. From late 1929 to early 1931 they issued 5 Canadian Msn’s for their Model 40s. However, only four were completed. Msn Canada-Boeing (CB-9) was not completed and put in storage then sold in 1936 to United Air Transport Canada. After which it was then given to Calgary Institute of Technology and Art. (AAHS Journal Summer 2004 volume 49 Number 2). That is why some historical aviation references refer to 81 Model 40 being built. The official recorded Msn’s from Boeing U.S. and Canada-Boeing records show the numbers to be 82 airframes built with 81 Model 40s that actual flew.

Figure 35 also shows seven Model 40 variation designations with four U.S. Aircraft Type Certifications assigned to six of the seven designations. The last certification was issued by the Canadian Government for their 5 Model 40s built by the Boeing Factory in Vancouver, B.C. However, in the literature covering the Model 40’s reference is made to two other Model 40 variations.

45 The following will be an attempt to explain these designations and the rational behind the designation.

The straight Model 40 built for the Post Office in 1925 did not receive an ATC number due to the fact it was designed and built before the regulations came into effect in 1926 under the Air Commerce Act.

The 25 Model 40As were built in 1927 for the Transcontinental Line and equipped with the Pratt & Whitney Wasp engines. They were issued ATC number 2 under the 1926 under the Air Commerce Act in July of 1927.

The Model 40Bs as mentioned earlier in the article were Model 40As modified with the higher 525 horsepower Pratt & Whitney Hornet engine. Due to their weight and performance numbers changes these aircraft had to be re-certified and were issued ATC number 27. However, the Model 40B was never a production Model 40 for Boeing since they were modified Model 40As.

The Boeing Model 40Cs were built after the Model 40As were converted to 40Bs. The Model 40C of which ten were built were identical to the Wasp-powered Model 40A except the rear mail bin compartment was converted to carry two additional passengers. They had two doors on the left hand side of the fuselage. The Model 40C received ATC number 54. They were delivered to airline customer, Pacific Air Transport, in August of 1928. They cost at the time $23,500. (Bower PNAHF Journal Vol. #8). One Model 40C went to National Park Airways. Later seven of the 10 Model 40Cs were converted to Model 40B-4s by the converting the Pratt & Whitney Hornet engine installed on their airframe.

The Model 40B-4, which 39 were built between 1929 and 1931 under ATC number 183 was a production 4 passenger aircraft with the Pratt & Whitney Hornet engine factory installed at the time of construction. When these aircraft became operational with Pacific Air Transport, Western Air Express, Varney Airlines and others it caused a retroactive Model designation change to the existing Model 40Bs flying with installed Hornet engine certified by ATC number 27. They remained under that certification ATC number but became Model 40B-2s to differentiate from the new four passenger Model 40B-4s under ATC number 183.

As discussed above there were the 5 Boeing-Canadian Model 40H-4s which were basically the same as the Model 40B-4s.

Additional there was also two one of a kind Model 40 variation with their own designation. These were the Model 40X and Model 40Y.

46 The Model 40X was a 4 passenger aircraft sold to Associated Oil Company in 1928 with Pratt & Whitney Wasp engine in 1928. It was built under ATC Number 53 used for the Model 40Cs. The Model 40Y also sold in 1928 was the Pratt & Whitney Hornet powered 4 passenger aircraft built under ATC # 183 and sold to Standard Oil of California.

Where Are They Now

Currently there are there two original Boeing Model 40s in existence. One is located in the Chicago Museum of Science and Industry where it hangs on display . The Chicago Museum of Science and Industry’s particular Model 40 is a Model 40B-2 Msn 888 which was displayed at the “Wings of a Century” pageant at the Century of Progress Exposition in Chicago in 1933. After the world fair exposition this aircraft with 6000 plus hours on the airframe was donated to the Rosenwald Museum (now called the Chicago Museum of Science and Industry) in November of 1933. Following a period of time in storage it was hung from the ceiling in 1939 where it remains and can be seen today.

The other is located in the Henry Ford Museum in Dearborn Michigan. This is also a Model 40B-2 Msn 896 with over 6000 hours on the airframe. The aircraft had an interesting history that included heavy repairs due to landing accidents, installation of 100 lbs radio equipment with mast and converted to an airline instrument trainer for National Air Transport. (AAHS Journal Vol 49 Number 2 summer 2004 p117)

However, there are three other Model 40s, two replicas and one reproduction. The two Model 40s replicas were by Century Aviation of East Wenatchee, WA. One is a Model 40B fuselage sitting on its landing gear in the Museum of Flight, Seattle Washington. This can be currently seen on display in the Museum’s Boeing Red Barn exhibit area. (figure37)

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Model 40B replica fuselage - The Museum of Flight Figure 37

The other is an exact replica of a Model 40B-2 delivered in October 2007 also to the Museum of Flight. This Model 40B-2 is part of The Museum of Flight’s Air Mail Exhibit in the Museum’s Great Gallery. The Model 40Bs for the Museum of Flight have been supported and inspired by Mr. William E Boeing Jr. son of The Boeing Company Founder William E. Boeing. The aviation community is very fortunate to be able to see up close the size and features of these historic aircraft from the ground level. Historical aircraft on display in this manner help to educate and bring alive the pioneering efforts of those who established the civil aircraft industry in the United States.

Also, in Washington State Pemberton & Sons Aviation has another Model 40 in restoration that is nearing completion. This one will be a flying reproduction of an original Model 40C. With the original data plate and 50 original components integrated into the reproduction this will be only flying example of a Model 40 in the world. This aircraft is also scheduled to make its debut within the next six-months. Pemberton & Sons intend to have this aircraft on display at selected air shows. They also plan to fly the CAM # 8 route between Seattle and Los Angles making stops along the route at or near the original airfields. That truly would be a wonderful “must see” event to witness this aircraft in the air once again.

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Pemberton & Sons Photo Pemberton & Sons Aviation Reproduction Model 40C Figure 38

Summary and Conclusion

Boeing constructed various marks of the Model 40 between 1926 and 1931. From an aircraft engineering, design and production point of view it was a basic aircraft even for its time. They receive little if any mention in aviation history books on their contribution to the industry. According to Heppenheimer’s authoritative history on the commercial aviation industry he stated. “In their technical design, airplanes in the 1920’s were generally failing to advance… One could see this in the Boeing 40 of 1927, built a decade after the war. It had an air cooled engine, but in other respects its layout remained thoroughly conventional. It showed a fuselage framework built of welded steel tubes, a construction technique that dated to 1916. Other features included the usual: open cockpit, biplane wings with spruce ribs fabric covering… This stodginess in design contrasted sharply with the great freedom available to designers”. (Heppenheimer 1995, p.15).

Yet the Boeing Model 40 was a historically significant aircraft if not from an engineering point of view but from the perspective they were the right aircraft, at the right time and place to play a significant role in the overall growth of aviation manufacturing and the airline industry. This point has been repeatedly missed in aviation histories of this era. The Model 40’s were an excellent aircraft to introduce the concept of the air cooled radial engine to the commercial aircraft market. Boeing Air Transport was able to make a profit in the first year of operation flying the line with the Model 40A.

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It is purely left to speculation as to what would have happen to the Boeing Company if they had not produced the Model 40A and win the San Francisco-Chicago portion of the Transcontinental Line. But without the Model 40s the Boeing Airplane Company at the time would not have been in a leadership role with Pratt & Whitney in forming the United Aircraft and Transport Corporation. As Museum of Flight exhibit Technician, historian and docent educator, John Little put it succinctly “The Boeing Model 40s were the most important aircraft Boeing ever designed or built, they allowed Boeing to survive and put them in the drivers seat when it came to the agreements of the mergers that formed UATC”. As a telling tribute as to what William E. Boeing thought of the Model 40 venture his son Mr. William E. Boeing Jr. told the author, “The Boeing Model 40 was the only picture of a Boeing airplane we had hanging anywhere in our house.” Apparently even at the time Mr. William E. Boeing realized the historical significant of the Model 40 to the Boeing Airplane Company. Perhaps to him the Model 40 represented the reaching of the goal he had set to achieve as stated in the articles of incorporation when he first set up the company, "To engage in the business of aerial navigation by any means whatsoever, heretofore or hereafter invented or developed, including also to act as a common carrier of passengers and freight by aerial navigation..." (Boeing Historical Archives- Articles of incorporation Pacific Aero Products 1916)

Century Aviation Photo Fig. 39 Century Aviation Built Boeing Model 40B for The Museum Of Flight First Public Roll Out Wenatchee, WA. October 6, 2007

50 Pictures of the constructions of The Museum of Flight Model 40B replica

2005-2007

A collection of photography’s of the Model 40B Construction

Figure 40

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Bibliography and References

Conversations

William Boeing Jr., Museum of Flight Trustee

Addison Pemberton, Pemberton and Sons Aviation, Model 40 Reproduction - Will be only one left flying.

Mark Smith, East Wenatchee Century Aviation, Model 40 Replica – Museum of Flight Model 40B replica and fuselage

Selected Websites

Air Mail Pioneers: www.airmailpioneers.org/

American Institute of Aeronautics and Astronautics: http://www.aiaa.org/

National Postal Museum; www.postalmuseum.si.edu

Pratt & Whitney: www.pratt-whitney.com

Smithsonian National Air and Space Museum: http://www.nasm.si.edu/

The Boeing Company: www.boeing.com

Periodicals

American Aviation Historical Society Journal

Volume 49, number 2 summer 2004

Archives

The Boeing Company - Seattle, Washington

The Museum of Flight – Seattle, Washington

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Books

Authors Name Title Publisher Year

Bowers, Peter Boeing Aircraft since 1916 Naval Institute Press 1989

Bowers, Peter Curtiss Aircraft 1907-1947 Putnam 1979

Brown, Jim Hubbard The Forgotten Boeing Aviator Peanut Butter 1996 Publishing

Dvaies, R.E.G. Airlines of The United States Since 1914 Smithsonian Institution 1982 Press Revised Edition Emme, Eugene M Two Hundred Years of Flight In America American 1977 Ed. Astronautically Society

Francillon, Rene' J. McDonnell Douglas Aircraft since 1920: Naval Institute Press 1979 Volume I

Hallion, Richard P. Legacy of Flight: The Guggenheim University of 1977 Contributions to Washington Press American Aviation

Heppenheimer, T.A. Turbulent Skies - The history of Wiley 1995 Commercial Aviation

Leary, William M. Aerial Pioneers The U.S. Air Mail Service, Smithsonian Institution 1985 1918-1927 Press

Pratt & Whitney, United Aircraft & Transport Corporation Pratt & Whitney (reprint) 1995 Presented by First Annual Report to Stockholders For the Year Ende3d December 31, 1929

Pratt & Whitney The Pratt & Whitney Aircraft Story Pratt & Whitney 1950 Commemoration of the 25 year

Smith, Herschel A History of the Aircraft Piston Engine Sunflower University 1986 Press van der Linden, Airlines & Air Mail: The Post Office and the The University Press of 2002 Robert F. Birth of the Kentucky Commercial Aviation Industry

Whitford, Ray Evolution of the Airliner The Crowood Press 2007

53 MIKE LAVELLE Museum of Flight Seattle, Washington

Mike Lavelle has over 46 years of aviation industry experience in aircraft flight and maintenance operations. Eleven of those years were with the Cessna Aircraft Company of Wichita Kansas and 24 years with The Boeing Company.

He is now Director of Development with the Museum of Flight in Seattle Washington.

Mike is a FAA flight and ground instructor, as well as a certified Airframe & Powerplant Mechanic. His over 7000 hours flying time include several hundred hours in vintage aircraft.

With a long time interest in aviation history, he has written papers and made aviation history presentations to air museums, The Imperial War Museum at Duxford, Branches of the Royal Aeronautical Society in the UK and United States, as well as, sections of AIAA. He was also a guest on NPR where he discussed early aviation history on the Science Friday Program.

Mike is a Fellow in the Royal Aeronautical Society and Associate Fellow of the American Institute of Aeronautics and Astronautics.

Mike and his wife live in Issaquah, Washington, and have two sons, both former US Army Rangers now working in industry.

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