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Boeing XB-15

October 29, 2023

The Boeing XB-15 (Boeing 294) was a United States bomber aircraft designed in 1934 as a test for the United States Army Air Corps (USAAC) to see if it would be possible to build a heavy bomber with a 5,000 mi (8,000 km) range. For a year beginning in mid-1935 it was designated the XBLR-1. When it first flew in 1937, it was the most massive and voluminous airplane ever built in the US. It set a number of load-to-altitude records for land-based aircraft, including carrying a 31,205 lb (14,154 kg) payload to 8,200 ft (2,500 m) on 30 July 1939.[1]

XB-15
XB-15 on a test flight
Role Heavy bomber
Manufacturer Boeing
First flight 15 October 1937
Status Canceled
Primary user United States Army Air Corps
Number built 1 prototype
Developed into Boeing Y1B-20

The aircraft's immense size allowed flight engineers to enter the wing through a crawlway and make minor repairs in flight. A 5,000 mi (8,000 km) flight took 33 hours at its 152 mph (245 km/h) cruising speed; the crew was made up of several shifts, and bunks allowed them to sleep when off duty.

Design and development edit

 
The XB-15's .50 in (12.7 mm) front gun turret

The specification that produced the XB-15 began in mid-1933 as "Project A", USAAC discussions regarding the possibility of flying a very large bomber with a range of 5,000 mi (8,000 km).[2] In April 1934 the USAAC contracted with Boeing and Martin to design a bomber capable of carrying 2,000 lb (910 kg) at 200 mph (320 km/h) over a distance of 5,000 miles.[3] Boeing gave the project the internal name of Model 294, while the USAAC called it the XB-15. Martin's design, the XB-16, was judged inferior by the USAAC before a prototype was built, and was canceled.[2]

The Boeing design team, headed by Jack Kylstra, initially intended the aircraft to use 2,600 hp (1,900 kW) Allison V-3420 liquid-cooled W engines; since these were not ready, 850 hp (630 kW) Pratt & Whitney R-1830 Twin Wasp air-cooled radial engines were used instead.[2]

Starting in August 1934, Boeing began designing the Model 299 in answer to a proposal by the USAAC to replace the Martin B-10 bomber. The Model 299 design team incorporated elements of the Boeing 247[4] and the Model 294, especially its use of four engines.[5] The Model 299 design team worked alongside Klystra's team, but difficulties in fabricating such a large aircraft slowed progress on the 294.[3] The Model 299 flew first, on 28 July 1935.[6]

In mid-1935, the USAAC combined Project A with Project D; a proposal asking for "the maximum feasible range into the future." The combined program was designated BLR for "Bomber, Long Range". The XB-15 was renamed the XBLR-1; it was joined under the BLR program by two other projects: one from Douglas Aircraft, the XBLR-2 which later became the XB-19; and one from Sikorsky Aircraft called the XBLR-3, later canceled. The next year, the XBLR was dropped and the Boeing prototype was once again the XB-15.[2]

Unusual features that the XB-15 pioneered included an autopilot, deicing equipment, and two gasoline generators used as auxiliary power units (independent of the main engines) to power the 110-volt electrical system. The main engines were serviceable in flight using an access tunnel inside the wing. The aircraft contained a sizable crew compartment with bunkbeds, a galley and a lavatory. Finally, in September 1937 construction was finished, and on 15 October it first flew. Its double-wheel main landing gear remained down from takeoff to landing. On 2 December 1937, the XB-15 flew from Seattle to Wright Field in Ohio to be accepted by the USAAC for testing.[7]

With the Twin Wasp radial engines installed — the same number and type of engines fitted to the later Consolidated B-24 Liberator, with individual turbochargers added on the Liberators' Twin Wasp powerplants — the specified speed of 200 mph for the Twin Wasp-powered XB-15 was not quite reached even when the aircraft was empty; the best speed attained in level flight was 197 mph (317 km/h).[7] Loaded with the specified 2,000 pounds, the maximum speed was a disappointing 145 mph (233 km/h).[3] This was considered too slow for a combat aircraft, and the project was abandoned.[8] However, Boeing engineers projected that the prototype would be capable of carrying the heaviest air cargo to date: a load of 8,000 lb (3,600 kg).[3]

The design challenges stemming from the great size of the XB-15 were difficult to master, but the lessons learned by Boeing were later applied to the Model 314 flying boat, which essentially used the XB-15's wing design[2] with four of the more powerful Wright Twin Cyclone fourteen-cylinder radials for power. In 1938, the USAAC proposed to update the XB-15 to make the slightly larger Y1B-20, again using four Wright Twin Cyclones as with the Boeing 314, but the Secretary of War, Harry Hines Woodring, canceled the project before construction began, in favor of the expensive Douglas XB-19. Boeing went ahead with an internal redesign of the XB-15 called Model 316, a very heavy bomber with a high wing, a pressurized cabin and tricycle gear. The Model 316 was not built. The progression of design work starting with the XB-15 finally bore fruit with the Model 345 presented to the USAAC in May 1940, the very heavy bomber which resulted in the USAAF's Boeing B-29 Superfortress.[7]

Operational history edit

 
A Red Cross agent and Major Caleb V. Haynes supervise the loading of emergency medical supplies on the XB-15 in early 1939

The single prototype was assigned to the 2nd Bombardment Group at Langley Field, Virginia. Following the 24 January 1939 Chillán earthquake in Chile, the prototype flew a relief mission, carrying medical supplies. Commanded by Major Caleb V. Haynes, the aircraft carried 3,250 lb (1,470 kg) of American Red Cross emergency supplies to Santiago, making only two stops along the way, at France Field in the Panama Canal Zone, and at Lima, Peru.[9][10] Haynes was awarded the Distinguished Flying Cross and the Order of the Merit of Chile, and the whole crew earned the MacKay Trophy.[9]

Haynes piloted the XB-15 again on 10 June 1939 to return home the body of Mexican flier Francisco Sarabia who had died in a crash in the Potomac River. After flying back from Mexico City, Haynes and his copilot William D. Old undertook flight tests at Fairfield, Ohio with heavy loads. The XB-15 lifted a 22,046 pounds (10,000 kg) payload to a height of 8,228 feet (2,508 m), and 31,164 pounds (14,136 kg) to 6,561.6 feet (2,000.0 m), setting two world records for landplanes.[11] Haynes was awarded certificates issued by the National Aeronautics Association (NAA) for an international record for "the greatest payload carried to an altitude of 2,000 metres".[12] The XB-15 was not fast for a bomber but it was the fastest aircraft that could carry so much weight, and for such distances. In July 1939 Haynes received certificates from the NAA for an international 5,000 km (3,100 mi) speed record with a 2,000 kg (4,400 lb) payload. The latter performance also established a national closed circuit distance record of 3,129.241 miles (5,036.025 km).[12]

Flying from Langley, the XB-15 arrived at Albrook Field in Panama on 10 April 1940 and immediately began classified bombing tests of canal lock protections, commanded by Haynes and including Captain Curtis LeMay as navigator and Lieutenant John B. Montgomery as bombardier.[13] Of 150 bombs dropped, only three hit the target: a specially made bunker simulating a reinforced machine room. The few hits nevertheless led to improvements in bunker design.[10] In early May, Haynes and LeMay made a survey flight from Panama over the Galapagos islands, the inspection including Baltra Island.[8] Haynes piloted the XB-15 back to the United States, leaving Panama on 11 May 1940.[13]

In late 1940 the XB-15's defensive guns were removed at Duncan Field in Texas. Seats were attached so that Lend Lease aircraft ferry crews could be returned after delivery.[13]

 
XC-105 "Grandpappy" in Panama
 
The XC-105 parked on Baltra Island in the Galápagos. Flying above are two Consolidated B-24 Liberators.
 
The flight crew in front of "Grandpappy" in Panama in 1943. Note the absence of the nose gun.

Cargo aircraft edit

On 6 May 1943 the Army Air Forces converted the only prototype into a transport, the aircraft being redesignated XC-105. A cargo hoist was mounted, and cargo doors fitted. Its maximum gross weight was increased to 92,000 lb (42,000 kg).[7] By this time, the aircraft was nicknamed "Grandpappy" by 20th Troop Carrier Squadron airmen.[14] It displayed nose art depicting an elephant carrying a large crate on its back labeled "supplies".[13] During World War II, the XC-105 carried freight and personnel to and from Florida, and throughout the Caribbean, based out of Albrook Field beginning in June 1943. Hundreds of young women were flown in "Grandpappy" from Miami to the Canal Zone to engage in US government work; these trips were dubbed the "Georgia Peach Run".[13] "Grandpappy" traveled to the Galapagos, landing on Baltra Island at the same airfield built following the XB-15 aerial survey of May 1940.[13]

"Grandpappy"′s flight crew, reduced to six men, described the aircraft as difficult to fly and service. Two fires and a complete failure of the electrical system occurred in the air.[7][13] The aircraft was retired on 18 December 1944, assigned to Panama Air Depot.[13] In June 1945, it was ordered to be scrapped at Albrook Field in Panama,[7] its engines and internal parts removed along with its vertical stabilizer and rudder. The remaining airframe was deposited at Diablo dump, a swampy landfill southwest of the runway, where it slowly sank from sight.[10][13][14] Squatters built shacks on stilts in the swamp, covering the remains. The former dump is now an industrial area, with "Grandpappy" underneath.[14]

During its 18 months of transport service, the XC-105 carried more than 5,200 passengers, 440,000 lb (200,000 kg) of cargo and 94,000 lb (43,000 kg) of mail. It flew 70 cargo trips and 60 missions including anti-submarine patrol. Unusually, the aircraft was consistently referred to as "he" by its crew.[13]

 
The XB-15 parked on an airstrip.

Operators edit

  United States
2d Bombardment Group
20th Troop Carrier Squadron

Specifications (XB-15) edit

Data from Boeing Aircraft since 1916.[15]

General characteristics

  • Crew: 10
  • Length: 87 ft 7 in (26.70 m)
  • Wingspan: 149 ft 0 in (45.43 m)
  • Height: 25 ft 10 in (7.87 m)
  • Wing area: 2,780 sq ft (258.4 m2)
  • Empty weight: 37,709 lb (17,141 kg)
  • Max takeoff weight: 70,706 lb (32,139 kg)
  • Powerplant: 4 × 14-cylinder Pratt & Whitney R-1830-11 radial engines, 1000 (take-off) 850 hp at 6,000ft hp (634 kW) each

Performance

  • Maximum speed: 197 mph (317 km/h, 171 kn) at 5,000 ft (1,500 m)[7]
  • Cruise speed: 152 mph (245 km/h, 132 kn) at 6,000 ft (1,800 m)
  • Range: 5,130 mi (8,260 km, 4,460 nmi)
  • Combat range: 3,400 mi (5,474 km, 2,957 nmi) [16]
  • Service ceiling: 18,900 ft (5,760 m)

Armament

See also edit

Related development

Aircraft of comparable role, configuration, and era

Related lists

References edit

Notes edit

  1. ^ Bowers says the record flight had a payload of 71,000+ lb (32,000+ kg) but the FAI record book shows 14,000+ kg (31,000+ lb)
  2. ^ a b c d e Yenne 2005, p. 43.
  3. ^ a b c d Moy 2001, pp. 70–72.
  4. ^ Swanborough and Bowers 1963, p. 74.
  5. ^ Moy 2001, p. 73.
  6. ^ . Boeing. Archived from the original on December 8, 2006. Retrieved 26 May 2012.
  7. ^ a b c d e f g Kohn 2002 pp. 43–44.
  8. ^ a b Boniface 1999, pp. 64–67.
  9. ^ a b Haulman, Daniel L.One Hundred Years of Flight: USAF Chronology of Significant Air and Space Events 1903–2002. Maxwell AFB, Alabama: Air Force History and Museums Program, Air University Press, 2003.
  10. ^ a b c Liang, Susan Hall. "Grandpappy's dead and buried, but he's not forgotten." The Panama Canal Spillway, 19 October 1979, p. 3. Retrieved: 26 May 2012. Hosted by the University of Florida Digital Collections, George A. Smathers Libraries.
  11. ^ Maurer 1987, pp. 304–307, 355–360, 405–406.
  12. ^ a b . Archived from the original on June 13, 2009. Retrieved June 25, 2014.
  13. ^ a b c d e f g h i j Bouché, Georges G. " 'Grandpappy'-The XB-15." Aerospace Historian, Air Force Historical Foundation, Volume 26, Number 3, September 1979, pp. 171–181.
  14. ^ a b c Millam, Ed S. Jr."Grandpappy". AAHS Journal' (American Aviation Historical Society), Volume 50, 2005, pp. 46–54.
  15. ^ Bowers 1989, p. 230.
  16. ^ . National Museum of the United States Air Force. Archived from the original on November 21, 2007. Retrieved 7 August 2009.

Bibliography edit

  • Boniface, Patrick. "Boeing's Forgotten Monster: XB-15 a Giant in Search of a Cause." Air Enthusiast, No. 79, January–February 1999. pp. 64–67. ISSN 0143-5450
  • Bowers, Peter M. Boeing Aircraft since 1916. London: Putnam, Third edition, 1989. ISBN 0-85177-804-6.
  • Kohn, Leo. "Boeing XB-15 Super Flying Fortress: U.S. Heavy Bomber". In Ray Merriam. "U. S. Warplanes of World War II." World War II Journal, 69. Bennington, Vermont: Merriam Press, 2002. ISBN 1-57638-167-6.
  • Maurer, Maurer. Aviation in the U.S. Army, 1919–1939. Washington, D.C.: United States Air Force Historical Research Center, Office of Air Force History, 1987. ISBN 0-912799-38-2.
  • Moy, Timothy. War Machines: Transforming Technologies in the U.S. Military, 1920–1940 (Texas A&M University Military History Series, 71)."] College Station, Texas: Texas A&M University Press, 2001. ISBN 1-58544-104-X.
  • Swanborough, F. Gordon and Peter M. Bowers. United States Military aircraft since 1909. London: Putnam, 1963.
  • Yenne, Bill. The Story of the Boeing Company. Minneapolis, Minnesota: Zenith Imprint, 2005. ISBN 0-76032-333-X.

External links edit

 
Wikimedia Commons has media related to Boeing XB-15.

October 29, 2023
boeing, boeing, united, states, bomber, aircraft, designed, 1934, test, united, states, army, corps, usaac, would, possible, build, heavy, bomber, with, range, year, beginning, 1935, designated, xblr, when, first, flew, 1937, most, massive, voluminous, airplan. The Boeing XB 15 Boeing 294 was a United States bomber aircraft designed in 1934 as a test for the United States Army Air Corps USAAC to see if it would be possible to build a heavy bomber with a 5 000 mi 8 000 km range For a year beginning in mid 1935 it was designated the XBLR 1 When it first flew in 1937 it was the most massive and voluminous airplane ever built in the US It set a number of load to altitude records for land based aircraft including carrying a 31 205 lb 14 154 kg payload to 8 200 ft 2 500 m on 30 July 1939 1 XB 15XB 15 on a test flightRole Heavy bomberManufacturer BoeingFirst flight 15 October 1937Status CanceledPrimary user United States Army Air CorpsNumber built 1 prototypeDeveloped into Boeing Y1B 20The aircraft s immense size allowed flight engineers to enter the wing through a crawlway and make minor repairs in flight A 5 000 mi 8 000 km flight took 33 hours at its 152 mph 245 km h cruising speed the crew was made up of several shifts and bunks allowed them to sleep when off duty Contents 1 Design and development 2 Operational history 2 1 Cargo aircraft 3 Operators 4 Specifications XB 15 5 See also 6 References 6 1 Notes 6 2 Bibliography 7 External linksDesign and development edit nbsp The XB 15 s 50 in 12 7 mm front gun turretThe specification that produced the XB 15 began in mid 1933 as Project A USAAC discussions regarding the possibility of flying a very large bomber with a range of 5 000 mi 8 000 km 2 In April 1934 the USAAC contracted with Boeing and Martin to design a bomber capable of carrying 2 000 lb 910 kg at 200 mph 320 km h over a distance of 5 000 miles 3 Boeing gave the project the internal name of Model 294 while the USAAC called it the XB 15 Martin s design the XB 16 was judged inferior by the USAAC before a prototype was built and was canceled 2 The Boeing design team headed by Jack Kylstra initially intended the aircraft to use 2 600 hp 1 900 kW Allison V 3420 liquid cooled W engines since these were not ready 850 hp 630 kW Pratt amp Whitney R 1830 Twin Wasp air cooled radial engines were used instead 2 Starting in August 1934 Boeing began designing the Model 299 in answer to a proposal by the USAAC to replace the Martin B 10 bomber The Model 299 design team incorporated elements of the Boeing 247 4 and the Model 294 especially its use of four engines 5 The Model 299 design team worked alongside Klystra s team but difficulties in fabricating such a large aircraft slowed progress on the 294 3 The Model 299 flew first on 28 July 1935 6 In mid 1935 the USAAC combined Project A with Project D a proposal asking for the maximum feasible range into the future The combined program was designated BLR for Bomber Long Range The XB 15 was renamed the XBLR 1 it was joined under the BLR program by two other projects one from Douglas Aircraft the XBLR 2 which later became the XB 19 and one from Sikorsky Aircraft called the XBLR 3 later canceled The next year the XBLR was dropped and the Boeing prototype was once again the XB 15 2 Unusual features that the XB 15 pioneered included an autopilot deicing equipment and two gasoline generators used as auxiliary power units independent of the main engines to power the 110 volt electrical system The main engines were serviceable in flight using an access tunnel inside the wing The aircraft contained a sizable crew compartment with bunkbeds a galley and a lavatory Finally in September 1937 construction was finished and on 15 October it first flew Its double wheel main landing gear remained down from takeoff to landing On 2 December 1937 the XB 15 flew from Seattle to Wright Field in Ohio to be accepted by the USAAC for testing 7 With the Twin Wasp radial engines installed the same number and type of engines fitted to the later Consolidated B 24 Liberator with individual turbochargers added on the Liberators Twin Wasp powerplants the specified speed of 200 mph for the Twin Wasp powered XB 15 was not quite reached even when the aircraft was empty the best speed attained in level flight was 197 mph 317 km h 7 Loaded with the specified 2 000 pounds the maximum speed was a disappointing 145 mph 233 km h 3 This was considered too slow for a combat aircraft and the project was abandoned 8 However Boeing engineers projected that the prototype would be capable of carrying the heaviest air cargo to date a load of 8 000 lb 3 600 kg 3 The design challenges stemming from the great size of the XB 15 were difficult to master but the lessons learned by Boeing were later applied to the Model 314 flying boat which essentially used the XB 15 s wing design 2 with four of the more powerful Wright Twin Cyclone fourteen cylinder radials for power In 1938 the USAAC proposed to update the XB 15 to make the slightly larger Y1B 20 again using four Wright Twin Cyclones as with the Boeing 314 but the Secretary of War Harry Hines Woodring canceled the project before construction began in favor of the expensive Douglas XB 19 Boeing went ahead with an internal redesign of the XB 15 called Model 316 a very heavy bomber with a high wing a pressurized cabin and tricycle gear The Model 316 was not built The progression of design work starting with the XB 15 finally bore fruit with the Model 345 presented to the USAAC in May 1940 the very heavy bomber which resulted in the USAAF s Boeing B 29 Superfortress 7 Operational history edit nbsp A Red Cross agent and Major Caleb V Haynes supervise the loading of emergency medical supplies on the XB 15 in early 1939The single prototype was assigned to the 2nd Bombardment Group at Langley Field Virginia Following the 24 January 1939 Chillan earthquake in Chile the prototype flew a relief mission carrying medical supplies Commanded by Major Caleb V Haynes the aircraft carried 3 250 lb 1 470 kg of American Red Cross emergency supplies to Santiago making only two stops along the way at France Field in the Panama Canal Zone and at Lima Peru 9 10 Haynes was awarded the Distinguished Flying Cross and the Order of the Merit of Chile and the whole crew earned the MacKay Trophy 9 Haynes piloted the XB 15 again on 10 June 1939 to return home the body of Mexican flier Francisco Sarabia who had died in a crash in the Potomac River After flying back from Mexico City Haynes and his copilot William D Old undertook flight tests at Fairfield Ohio with heavy loads The XB 15 lifted a 22 046 pounds 10 000 kg payload to a height of 8 228 feet 2 508 m and 31 164 pounds 14 136 kg to 6 561 6 feet 2 000 0 m setting two world records for landplanes 11 Haynes was awarded certificates issued by the National Aeronautics Association NAA for an international record for the greatest payload carried to an altitude of 2 000 metres 12 The XB 15 was not fast for a bomber but it was the fastest aircraft that could carry so much weight and for such distances In July 1939 Haynes received certificates from the NAA for an international 5 000 km 3 100 mi speed record with a 2 000 kg 4 400 lb payload The latter performance also established a national closed circuit distance record of 3 129 241 miles 5 036 025 km 12 Flying from Langley the XB 15 arrived at Albrook Field in Panama on 10 April 1940 and immediately began classified bombing tests of canal lock protections commanded by Haynes and including Captain Curtis LeMay as navigator and Lieutenant John B Montgomery as bombardier 13 Of 150 bombs dropped only three hit the target a specially made bunker simulating a reinforced machine room The few hits nevertheless led to improvements in bunker design 10 In early May Haynes and LeMay made a survey flight from Panama over the Galapagos islands the inspection including Baltra Island 8 Haynes piloted the XB 15 back to the United States leaving Panama on 11 May 1940 13 In late 1940 the XB 15 s defensive guns were removed at Duncan Field in Texas Seats were attached so that Lend Lease aircraft ferry crews could be returned after delivery 13 nbsp XC 105 Grandpappy in Panama nbsp The XC 105 parked on Baltra Island in the Galapagos Flying above are two Consolidated B 24 Liberators nbsp The flight crew in front of Grandpappy in Panama in 1943 Note the absence of the nose gun Cargo aircraft edit On 6 May 1943 the Army Air Forces converted the only prototype into a transport the aircraft being redesignated XC 105 A cargo hoist was mounted and cargo doors fitted Its maximum gross weight was increased to 92 000 lb 42 000 kg 7 By this time the aircraft was nicknamed Grandpappy by 20th Troop Carrier Squadron airmen 14 It displayed nose art depicting an elephant carrying a large crate on its back labeled supplies 13 During World War II the XC 105 carried freight and personnel to and from Florida and throughout the Caribbean based out of Albrook Field beginning in June 1943 Hundreds of young women were flown in Grandpappy from Miami to the Canal Zone to engage in US government work these trips were dubbed the Georgia Peach Run 13 Grandpappy traveled to the Galapagos landing on Baltra Island at the same airfield built following the XB 15 aerial survey of May 1940 13 Grandpappy s flight crew reduced to six men described the aircraft as difficult to fly and service Two fires and a complete failure of the electrical system occurred in the air 7 13 The aircraft was retired on 18 December 1944 assigned to Panama Air Depot 13 In June 1945 it was ordered to be scrapped at Albrook Field in Panama 7 its engines and internal parts removed along with its vertical stabilizer and rudder The remaining airframe was deposited at Diablo dump a swampy landfill southwest of the runway where it slowly sank from sight 10 13 14 Squatters built shacks on stilts in the swamp covering the remains The former dump is now an industrial area with Grandpappy underneath 14 During its 18 months of transport service the XC 105 carried more than 5 200 passengers 440 000 lb 200 000 kg of cargo and 94 000 lb 43 000 kg of mail It flew 70 cargo trips and 60 missions including anti submarine patrol Unusually the aircraft was consistently referred to as he by its crew 13 nbsp The XB 15 parked on an airstrip Operators edit nbsp United StatesUnited States Army Air Corps2d Bombardment GroupUnited States Army Air Forces20th Troop Carrier SquadronSpecifications XB 15 editData from Boeing Aircraft since 1916 15 General characteristicsCrew 10 Length 87 ft 7 in 26 70 m Wingspan 149 ft 0 in 45 43 m Height 25 ft 10 in 7 87 m Wing area 2 780 sq ft 258 4 m2 Empty weight 37 709 lb 17 141 kg Max takeoff weight 70 706 lb 32 139 kg Powerplant 4 14 cylinder Pratt amp Whitney R 1830 11 radial engines 1000 take off 850 hp at 6 000ft hp 634 kW eachPerformance Maximum speed 197 mph 317 km h 171 kn at 5 000 ft 1 500 m 7 Cruise speed 152 mph 245 km h 132 kn at 6 000 ft 1 800 m Range 5 130 mi 8 260 km 4 460 nmi Combat range 3 400 mi 5 474 km 2 957 nmi 16 Service ceiling 18 900 ft 5 760 m Armament Guns 3 30 in 7 62 mm M1919 Browning machine guns 3 50 in 12 7 mm M2 Browning machine guns Bombs 12 000 lb 5 400 kg See also edit nbsp Aviation portalRelated development Boeing B 17 Flying Fortress Boeing Y1B 20 Boeing 314 which used the XB 15 s wing designAircraft of comparable role configuration and era Martin XB 16 Petlyakov Pe 8 Nakajima G5NRelated lists List of bomber aircraft List of military aircraft of the United StatesReferences editNotes edit Bowers says the record flight had a payload of 71 000 lb 32 000 kg but the FAI record book shows 14 000 kg 31 000 lb a b c d e Yenne 2005 p 43 a b c d Moy 2001 pp 70 72 Swanborough and Bowers 1963 p 74 Moy 2001 p 73 History The Boeing Logbook 1933 1938 Boeing Archived from the original on December 8 2006 Retrieved 26 May 2012 a b c d e f g Kohn 2002 pp 43 44 a b Boniface 1999 pp 64 67 a b Haulman Daniel L One Hundred Years of Flight USAF Chronology of Significant Air and Space Events 1903 2002 Maxwell AFB Alabama Air Force History and Museums Program Air University Press 2003 a b c Liang Susan Hall Grandpappy s dead and buried but he s not forgotten The Panama Canal Spillway 19 October 1979 p 3 Retrieved 26 May 2012 Hosted by the University of Florida Digital Collections George A Smathers Libraries Maurer 1987 pp 304 307 355 360 405 406 a b USAF Biography Major General Caleb V Haynes Archived from the original on June 13 2009 Retrieved June 25 2014 a b c d e f g h i j Bouche Georges G Grandpappy The XB 15 Aerospace Historian Air Force Historical Foundation Volume 26 Number 3 September 1979 pp 171 181 a b c Millam Ed S Jr Grandpappy AAHS Journal American Aviation Historical Society Volume 50 2005 pp 46 54 Bowers 1989 p 230 Fact Sheets Boeing XB 15 National Museum of the United States Air Force Archived from the original on November 21 2007 Retrieved 7 August 2009 Bibliography edit Boniface Patrick Boeing s Forgotten Monster XB 15 a Giant in Search of a Cause Air Enthusiast No 79 January February 1999 pp 64 67 ISSN 0143 5450 Bowers Peter M Boeing Aircraft since 1916 London Putnam Third edition 1989 ISBN 0 85177 804 6 Kohn Leo Boeing XB 15 Super Flying Fortress U S Heavy Bomber In Ray Merriam U S Warplanes of World War II World War II Journal 69 Bennington Vermont Merriam Press 2002 ISBN 1 57638 167 6 Maurer Maurer Aviation in the U S Army 1919 1939 Washington D C United States Air Force Historical Research Center Office of Air Force History 1987 ISBN 0 912799 38 2 Moy Timothy War Machines Transforming Technologies in the U S Military 1920 1940 Texas A amp M University Military History Series 71 College Station Texas Texas A amp M University Press 2001 ISBN 1 58544 104 X Swanborough F Gordon and Peter M Bowers United States Military aircraft since 1909 London Putnam 1963 Yenne Bill The Story of the Boeing Company Minneapolis Minnesota Zenith Imprint 2005 ISBN 0 76032 333 X External links edit nbsp Wikimedia Commons has media related to Boeing XB 15 Boeing s description of the XB 15 Encyclopedia of American aircraft USAF Museum description of XB 15 Retrieved from https en wikipedia org w index php title Boeing XB 15 amp oldid 1156421310, wikipedia, wiki, book, books, library,

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