Misplaced Pages

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162-836: In earlier days, most larger aircraft were designed and built with a flight engineer's position. For U.S. civilian aircraft that require a flight engineer as part of the crew, the flight engineer must possess an FAA Flight Engineer Certificate with reciprocating, turboprop, or turbojet ratings appropriate to the aircraft. Whereas the four-engine Douglas DC-4 did not require a flight engineer, the FAA type certificates of subsequent four-engine reciprocating engine airplanes ( Boeing 307 and 377 , DC-6 , DC-7 , Constellation ) and early two-, three- and four-engine jets ( Boeing 707 , 727 , early 747s , DC-8 , DC-10 , L-1011 , early A300s ) required them. Smaller twinjets ( DC-9 , 737 , BAC 1-11 , Caravelle , Dassault Mercure ) were never complex enough to require

324-495: A horseshoe . In the case of a distribution of separate bodies, such as the planets of the Solar System , the center of mass may not correspond to the position of any individual member of the system. The center of mass is a useful reference point for calculations in mechanics that involve masses distributed in space, such as the linear and angular momentum of planetary bodies and rigid body dynamics . In orbital mechanics ,

486-529: A 212.5 US gal (804 L; 176.9 imp gal) fuel tank located between the inner and outer nacelles, on both sides of the aircraft, providing a total of 1,700 US gal (6,400 L; 1,400 imp gal) of fuel in six tanks. With the fuselage being 3.5 ft (1.1 m) wider than on the B-17, the span had increased from 103 ft 9 in (31.62 m) to 107 ft 3 in (32.69 m) compared to early B-17s. After being modified,

648-498: A Master Bedroom, two bathrooms, a galley and a bar as well as a living room. In 1949, Hughes spent an additional $ 100,000 renovating it so he could sell it, which, like the T&;WA and Pan Am aircraft now included an interior designed by Raymond Loewy . Oil tycoon Glenn McCarthy bought it to coincide with the opening of his new Shamrock Hotel and he renamed it Shamrock and had it repainted, however McCarthy defaulted on payments and it

810-545: A captain) but with civilian insignia. The first ICD service flight began on February 26, when a 307 flew south to Brazil from Washington, before crossing the South Atlantic to Africa, and north to Cairo, before continuing on to Prestwick, Scotland where they arrived on April 20, 1942, having primarily carried 25,000 rounds of armour piercing shells to British troops in Cairo, who were facing Rommel and his Afrika Corps . ICD

972-682: A circle instead of a line. The calculation takes every particle's x coordinate and maps it to an angle, θ i = x i x max 2 π {\displaystyle \theta _{i}={\frac {x_{i}}{x_{\max }}}2\pi } where x max is the system size in the x direction and x i ∈ [ 0 , x max ) {\displaystyle x_{i}\in [0,x_{\max })} . From this angle, two new points ( ξ i , ζ i ) {\displaystyle (\xi _{i},\zeta _{i})} can be generated, which can be weighted by

1134-514: A contract with Douglas to develop the 40 passenger DC-4 (later known as the DC-4E). Each company contributed $ 100,000 to development costs and agreed to not operate other aircraft with a maximum weight of 43,000 to 75,000 lb (20,000 to 34,000 kg) for revenue service. Due to development problems and poor performance, all of the airlines dropped out of the DC-4 program and cancelled their orders, but

1296-518: A few weeks later, on September 26, a TWA New York bound Stratoliner at 17,000 ft (5,200 m) with a jetstream providing a strong tailwind reached a ground speed of 387 mph (623 km/h). Flight 45 added additional stops at Philadelphia and Pittsburgh on December 1, 1940. On December 14, 1941, representatives from various airlines as well as the Air Transport Association of America (ATA) met with Colonel Robert Olds of

1458-607: A flight engineer's position. However, this position also doubled as a gunner, usually operating the upper turret, as was the case of the Boeing B-17 Flying Fortress . On some commercial airliners with a flight engineer, the FE is the third in command, after the captain and first officer . Unlike commercial pilots, the Federal Aviation Administration never set a mandatory retirement age for flight engineers. As

1620-410: A flight engineer, while later large two, three, and four-engine jets ( Airbus A310 , A300-600 , Boeing 767 , MD-11 , 747-400 , and later) were designed with sufficient automation as to eliminate the need for the position. In order to dedicate a person to monitor an aircraft's engines and its other critical flight systems, the position of "flight engineer" (FE) was created. The FE did not actually fly

1782-732: A floating object is the one that makes its center of mass as low as possible. He developed mathematical techniques for finding the centers of mass of objects of uniform density of various well-defined shapes. Other ancient mathematicians who contributed to the theory of the center of mass include Hero of Alexandria and Pappus of Alexandria . In the Renaissance and Early Modern periods, work by Guido Ubaldi , Francesco Maurolico , Federico Commandino , Evangelista Torricelli , Simon Stevin , Luca Valerio , Jean-Charles de la Faille , Paul Guldin , John Wallis , Christiaan Huygens , Louis Carré , Pierre Varignon , and Alexis Clairaut expanded

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1944-567: A larger more suitable design, and they that they would use it for familiarization training with four engine aircraft. They required that it fly on just two engines, use Pratt & Whitney automatic mixture controls, have a 2,500 mi (4,000 km) range, be able to carry freight or mail, and have moderate tire ground pressure. KLM then requested a quote for three 307s, either with Wright Cyclones and with Pratt & Whitney 1830 engines, fitted with constant speed propellers and automatic carburettor mixture control and with additional fuel to provide

2106-574: A loosening of the tightly controlled government access to routes. TWA's fare structure remained the same as pre-war. New TWA flight routes were added with routes 370 & 371 between La Guardia and Spokane with intermediate stops in Chicago, Albuquerque, for fuel, and Burbank and routes 48 & 49 between La Guardia and Kansas City with a stop in St Louis. At this time, the TWA Stratoliners were briefly

2268-425: A malfunction, abnormality or emergency occurs, it is displayed on an electronic display panel. One pilot does the flying while the other pilot starts reading and executing the quick reference handbook (QRH) to resolve the problem. Modern technological advancements in today's aircraft have reduced the dependence upon human control over systems. The most recent aircraft built with FE stations include military variants of

2430-411: A metal structure, and were aerodynamically balanced and fitted with adjustable trim tabs to lighten flight loads. The rudder and elevators also had hydraulic boost, to lighten control forces. The partially retractable main undercarriage had hydraulic brakes and used Goodyear 55x19x23 tires, and was raised and lowered with electric motors. Manual backups were provided for electrically driven systems, but

2592-636: A pressure relief valve prevented the pressure difference from exceeding 2.65 lb/sq ft (12.9 kg/m ). The structure consisted of continuous longitudinal stiffeners spaced every 9 degrees around the fuselage with radial hoop stiffeners mounted every 16 in (410 mm) along the fuselage, reinforcing the similarity to a dirigible. The skin seams were sealed with tape impregnated with sealing compound trapped between lapped joints which were secured with two rows of rivets spaced 5 ⁄ 8  in (16 mm) apart, while doors and hatches were sealed with soft rubber gaskets and control cables entered

2754-453: A pressurized version, on July 27, 1938, but nothing came of these discussions and ANA never operated the type. The first customer delivery was to millionaire Howard Hughes on July 13, 1939. He bought aircraft serial number 1997 registered as NX19904 for $ 315,000 for a round-the-world flight, hoping to break his own record of 91 hours 14 minutes set between July 10 and 14 in 1938 in a Lockheed Model 14 Super Electra . Hughes' Stratoliner

2916-399: A range of 3,400 mi (5,500 km). Boeing responded that the price for three aircraft would be $ 289,000 each if fitted with Cyclone engines or $ 314,000 if fitted with R-1830s, plus $ 3,100 - $ 4,000 per aircraft to increasing fuel capacity to either 1,700 US gal (6,400 L; 1,400 imp gal) or 2,125 US gal (8,040 L; 1,769 imp gal), provided that

3078-471: A requirement for a large 4 engine airliner remained. Donald Webb Tomlinson at T&WA carried out five years of high altitude flight research, with a Northrop Gamma and a Douglas DC-1 , which helped determine that T&WA would need a four-engine airliner with a pressurized cabin. During this period, He also test flew the XB-17 and determined that it would provide an ideal basis for an airliner, and so Boeing

3240-573: A result, some pilots would voluntarily downgrade themselves when turning 60. This policy was the subject of two U.S. Supreme Court cases in 1985, when it ruled against Western Airlines that forced retirement of flight engineers based on the regulations for pilots was a violation of the Age Discrimination in Employment Act . Earlier in the year it had rejected a policy that prevented pilots from "bumping" flight engineers from their positions upon

3402-698: A single pilot. The first Allied military operation during the Second World War involving FEs occurred in February 1941 with a Short Stirling ; it was the first four-engined bomber-raid of the war by the RAF . The flight engineer ("air engineer" in the Royal Air Force) is primarily concerned with the operation and monitoring of all aircraft systems, and is required to diagnose, and where possible rectify or eliminate, any faults that may arise. On most multi-engine airplanes,

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3564-414: A sink, plush upholstered stools, soft indirect lighting provided by fluorescent lamps , ashtrays , hot and cold running water, shelves with towels, and a separate cubicle for the toilet. The men's washroom was in front as the "Men's Lounge", and also had a separate cubicle for the toilet, two sinks, and outlets to run an electric razor . A galley of just 28 sq ft (2.6 m ) provided hot food

3726-1126: A subsidiary, the Intercontinental Division (ICD), whose civilian crews would operate them on behalf of the United States Army Air Forces. Otis Bryan was made head of the ICD The Stratoliners were sold to the USAAF, who assigned the type the C-75 designation, and each of them was given a USAAF serial number. The first of these was accepted by the USAAF on March 1, 1941, and the last one on December 17, 1942. ICD crews included pilots, 1st & 2nd officers, navigators, flight engineers, flight radio operators and pursers. ICD Supervisor pilots and captains were paid $ 1100/month, first officers $ 800/month, Navigators $ 600/month, Flight Engineers (FEs) $ 500/month and Flight Radio Operators (FROs) $ 400/month. Personnel were issued with USAAF uniforms which they wore with rank stripes (two solid stripes for

3888-621: A test-flight on March 18, 1939, killing all 10 occupants, and forced several design changes, of which the fin and rudder are the most immediately obvious. KLM was considering four-engine airliners for the European routes, and a longer ranged four-engine aircraft for their routes to the Netherlands East Indies (now Indonesia). Aircraft considered included the Douglas DC-4 (E), the Boeing 307,

4050-400: A uniform field, thus arriving at the mathematical properties of what we now call the center of mass. Archimedes showed that the torque exerted on a lever by weights resting at various points along the lever is the same as what it would be if all of the weights were moved to a single point—their center of mass. In his work On Floating Bodies , Archimedes demonstrated that the orientation of

4212-437: A wobble pump, along with a rest area for the crew. A desk was added behind the pilot for a radio operator, who had a 50 watt Bendix TA-12 high frequency Morse transmitter, and a BC-348 tunable receiver. A 400 ft (120 m) trailing wire antenna was used with a 5 lb (2.3 kg) lead weight on the end - which the radio operator needed to remember to reel in, by hand, when landing. Inexperience sometimes led to either

4374-413: Is a particle with its mass concentrated at the center of mass. By selecting the center of gravity as the reference point for a rigid body, the gravity forces will not cause the body to rotate, which means the weight of the body can be considered to be concentrated at the center of mass. The linear and angular momentum of a collection of particles can be simplified by measuring the position and velocity of

4536-422: Is always directly below the rotorhead . In forward flight, the center of mass will move forward to balance the negative pitch torque produced by applying cyclic control to propel the helicopter forward; consequently a cruising helicopter flies "nose-down" in level flight. The center of mass plays an important role in astronomy and astrophysics, where it is commonly referred to as the barycenter . The barycenter

4698-593: Is an American stressed-skin four-engine low-wing tailwheel monoplane airliner derived from the B-17 Flying Fortress bomber, which entered commercial service in July 1940. It was the first airliner in revenue service with a pressurized cabin , which with supercharged engines, allowed it to cruise above the weather. As such it represented a major advance over contemporaries, with a cruising speed of 220 mph (350 km/h) at 20,000 ft (6,100 m) compared to

4860-668: Is chosen as the center of mass these equations simplify to p = m v , L = ∑ i = 1 n m i ( r i − R ) × d d t ( r i − R ) + ∑ i = 1 n m i R × v {\displaystyle \mathbf {p} =m\mathbf {v} ,\quad \mathbf {L} =\sum _{i=1}^{n}m_{i}(\mathbf {r} _{i}-\mathbf {R} )\times {\frac {d}{dt}}(\mathbf {r} _{i}-\mathbf {R} )+\sum _{i=1}^{n}m_{i}\mathbf {R} \times \mathbf {v} } where m

5022-468: Is crucial, possibly resulting in severe injury or death if assumed incorrectly. A center of gravity that is at or above the lift point will most likely result in a tip-over incident. In general, the further the center of gravity below the pick point, the safer the lift. There are other things to consider, such as shifting loads, strength of the load and mass, distance between pick points, and number of pick points. Specifically, when selecting lift points, it

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5184-432: Is something of a colloquialism, but it is in common usage and when gravity gradient effects are negligible, center-of-gravity and mass-center are the same and are used interchangeably. In physics the benefits of using the center of mass to model a mass distribution can be seen by considering the resultant of the gravity forces on a continuous body. Consider a body Q of volume V with density ρ ( r ) at each point r in

5346-1708: Is the mass at the point r , g is the acceleration of gravity, and k ^ {\textstyle \mathbf {\hat {k}} } is a unit vector defining the vertical direction. Choose a reference point R in the volume and compute the resultant force and torque at this point, F = ∭ Q f ( r ) d V = ∭ Q ρ ( r ) d V ( − g k ^ ) = − M g k ^ , {\displaystyle \mathbf {F} =\iiint _{Q}\mathbf {f} (\mathbf {r} )\,dV=\iiint _{Q}\rho (\mathbf {r} )\,dV\left(-g\mathbf {\hat {k}} \right)=-Mg\mathbf {\hat {k}} ,} and T = ∭ Q ( r − R ) × f ( r ) d V = ∭ Q ( r − R ) × ( − g ρ ( r ) d V k ^ ) = ( ∭ Q ρ ( r ) ( r − R ) d V ) × ( − g k ^ ) . {\displaystyle \mathbf {T} =\iiint _{Q}(\mathbf {r} -\mathbf {R} )\times \mathbf {f} (\mathbf {r} )\,dV=\iiint _{Q}(\mathbf {r} -\mathbf {R} )\times \left(-g\rho (\mathbf {r} )\,dV\,\mathbf {\hat {k}} \right)=\left(\iiint _{Q}\rho (\mathbf {r} )\left(\mathbf {r} -\mathbf {R} \right)dV\right)\times \left(-g\mathbf {\hat {k}} \right).} If

5508-503: Is the point between two objects where they balance each other; it is the center of mass where two or more celestial bodies orbit each other. When a moon orbits a planet , or a planet orbits a star , both bodies are actually orbiting a point that lies away from the center of the primary (larger) body. For example, the Moon does not orbit the exact center of the Earth , but a point on a line between

5670-903: Is the sum of the masses of all of the particles. These values are mapped back into a new angle, θ ¯ {\displaystyle {\overline {\theta }}} , from which the x coordinate of the center of mass can be obtained: θ ¯ = atan2 ⁡ ( − ζ ¯ , − ξ ¯ ) + π x com = x max θ ¯ 2 π {\displaystyle {\begin{aligned}{\overline {\theta }}&=\operatorname {atan2} \left(-{\overline {\zeta }},-{\overline {\xi }}\right)+\pi \\x_{\text{com}}&=x_{\max }{\frac {\overline {\theta }}{2\pi }}\end{aligned}}} The process can be repeated for all dimensions of

5832-427: Is the systems expert of the airplane with an extensive mechanical and technical knowledge of aircraft systems and aircraft performance. On some military airplanes ( Lockheed C-5 Galaxy , Boeing E-3 Sentry , McDonnell Douglas KC-10 ) the FE sits behind the co-pilot in the cockpit , facing outboard to operate a panel of switches, gauges and indicators or forward to operate throttles, lighting controls, flight controls. On

5994-474: Is the total mass of all the particles, p is the linear momentum, and L is the angular momentum. The law of conservation of momentum predicts that for any system not subjected to external forces the momentum of the system will remain constant, which means the center of mass will move with constant velocity. This applies for all systems with classical internal forces, including magnetic fields, electric fields, chemical reactions, and so on. More formally, this

6156-1282: Is the unit vector in the vertical direction). Let r 1 , r 2 , and r 3 be the position coordinates of the support points, then the coordinates R of the center of mass satisfy the condition that the resultant torque is zero, T = ( r 1 − R ) × F 1 + ( r 2 − R ) × F 2 + ( r 3 − R ) × F 3 = 0 , {\displaystyle \mathbf {T} =(\mathbf {r} _{1}-\mathbf {R} )\times \mathbf {F} _{1}+(\mathbf {r} _{2}-\mathbf {R} )\times \mathbf {F} _{2}+(\mathbf {r} _{3}-\mathbf {R} )\times \mathbf {F} _{3}=0,} or R × ( − W k ^ ) = r 1 × F 1 + r 2 × F 2 + r 3 × F 3 . {\displaystyle \mathbf {R} \times \left(-W\mathbf {\hat {k}} \right)=\mathbf {r} _{1}\times \mathbf {F} _{1}+\mathbf {r} _{2}\times \mathbf {F} _{2}+\mathbf {r} _{3}\times \mathbf {F} _{3}.} This equation yields

6318-434: Is true for any internal forces that cancel in accordance with Newton's Third Law . The experimental determination of a body's center of mass makes use of gravity forces on the body and is based on the fact that the center of mass is the same as the center of gravity in the parallel gravity field near the earth's surface. The center of mass of a body with an axis of symmetry and constant density must lie on this axis. Thus,

6480-418: Is undefined. This is a correct result, because it only occurs when all particles are exactly evenly spaced. In that condition, their x coordinates are mathematically identical in a periodic system . A body's center of gravity is the point around which the resultant torque due to gravity forces vanishes. Where a gravity field can be considered to be uniform, the mass-center and the center-of-gravity will be

6642-416: Is very important to place the center of gravity at the center and well below the lift points. The center of mass of the adult human body is 10 cm above the trochanter (the femur joins the hip). In kinesiology and biomechanics, the center of mass is an important parameter that assists people in understanding their human locomotion. Typically, a human's center of mass is detected with one of two methods:

Flight engineer - Misplaced Pages Continue

6804-1141: The ( ξ , ζ ) {\displaystyle (\xi ,\zeta )} plane, these coordinates lie on a circle of radius 1. From the collection of ξ i {\displaystyle \xi _{i}} and ζ i {\displaystyle \zeta _{i}} values from all the particles, the averages ξ ¯ {\displaystyle {\overline {\xi }}} and ζ ¯ {\displaystyle {\overline {\zeta }}} are calculated. ξ ¯ = 1 M ∑ i = 1 n m i ξ i , ζ ¯ = 1 M ∑ i = 1 n m i ζ i , {\displaystyle {\begin{aligned}{\overline {\xi }}&={\frac {1}{M}}\sum _{i=1}^{n}m_{i}\xi _{i},\\{\overline {\zeta }}&={\frac {1}{M}}\sum _{i=1}^{n}m_{i}\zeta _{i},\end{aligned}}} where M

6966-533: The Air Corps Ferrying Command (later renamed Air Transport Command) over the use of their airliners in wartime. Pan Am had already signed a contract on the 13th, in which it would keep its 307s, but sell the 314s to the government. T&WA sold all five of its 307s to the USAAF, but would then operate them on behalf of the USAAF on a cost plus basis though a new subsidiary. At the time the Stratoliner

7128-707: The Boeing 707 , such as the E-3 Sentry and E-6 Mercury , both built through 1991, the Tupolev Tu-154 , the final example of which was delivered in 2013, and the Scaled Composites Stratolaunch whose sole example first flew in 2019. The last major US passenger airline to fly aircraft equipped with a flight engineer's station was Northwest Airlines , who retired their final 747-200s from charter service in 2009. The final major cargo operator to employ flight engineers

7290-557: The Boeing Model 299 B-17 Flying Fortress heavy bomber as the Model 307. It combined the wings, tail, rudder, undercarriage, and engines from the B-17 with a new, much larger pressurized circular cross-section fuselage with a maximum diameter of 138 in (3.5 m). The pressurization system required extensive testing, which was carried out over many months, progressively increasing the air pressure after each successful test, and each time,

7452-683: The Cosmic Muffin , in which form it still survives. As one of the companies sponsoring the development of the Douglas DC-4, Transcontinental & Western Air lost interest due to delays and poor performance, but the agreement they signed with Douglas limited the maximum weight of any replacement design to 43,000 lbs. After discussing their needs with Boeing, T&WA signed a contract with Boeing to buy six 307s with an option for 13 more for $ 1,590,000 on January 29, 1937, with deliveries to be made in mid-1938. T&WA defaulted on their payments though and

7614-588: The Douglas DC-3 's 160 mph (260 km/h), at 8,000 ft (2,400 m) then in service. When it entered commercial service it had a crew of five to six, including two pilots, a flight engineer , two flight attendants and an optional navigator , and had a capacity for 33 passengers, which later modifications increased, first to 38, and eventually to 60. In 1935, Pan American Airways , United Airlines , American Airlines , Eastern Air Lines and Transcontinental & Western Air (T&WA) had each signed

7776-635: The Gander, Newfoundland - Scotland leg distance. The first aircraft to land at these fields, which were north of the Arctic Circle, was an ICD C-75, on April 20, 1942. Marshall, Eisenhower, "Hap" Arnold and Admirals King and Towers flew to London from Washington via Montreal, Gander and Prestwick on May 23, 1942, and returned to Washington via Prestwick, Reykjavik and Gander. On June 20, 1942, Air Corps Ferrying Command became Air Transport Command The exiled (but not yet deposed) King Peter II of Yugoslavia

7938-702: The Junkers Ju 90 , the Focke-Wulf Fw 200 Condor , and the Bloch 160 , of which only the DC-4 and 307 came close to meeting their requirements Boeing made a proposal to KLM on September 20, 1936, for exclusive option on 10 certified 307s for $ 2.4 million with options for 18 aircraft and with first delivery in 14 months. By January 14, 1937, the price had increased for 18 aircraft to $ 265,000 each, not including pressurization equipment. KLM let Boeing know that they were interested in 4 aircraft, for use as an interim measure pending

8100-656: The Lockheed C-69 Constellation would not fly until January 1943, while aircraft with two engines were considered unsafe for ocean crossings with VIPs on board. On the entry of the United States into World War II , Pan Am continued operating its Stratoliners on routes to Central and South America , but under direction of the Army Air Forces' Air Transport Command, All five TWA Stratoliners were withdrawn from operations on December 24, 1941, while TWA created

8262-755: The Tupolev Tu-134 the FE sits in the nose of the aircraft. On other western military airplanes, such as on the Lockheed P-3 Orion and Lockheed C-130H Hercules , FEs sit between, slightly aft of (and, in the case of the C-130A-H models, slightly higher than) the pilots. On the P-3 Orion, E-6B Mercury and E-3 Sentry the FE is responsible for starting and shutting down engines at the start and end of each flight, and also during in-flight shutdowns which are carried out to save fuel on long range operations. In some militaries,

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8424-515: The lend-lease program. From April 22, regular crossings were being made. and ICD was growing rapidly, growing from 71 personnel in January, to 343 by April, and they were now making 16 ocean crossings a month. Following his April 1942 raid on Tokyo , but before it had been made public, Jimmy Doolittle took a C-75 from Karachi in India through Khartoum , Kano , Accra , Robertsfield Airport , crossed

8586-628: The navigator . Earlier referred to as a "flight mechanic" on the four-engine commercial seaplanes like the Sikorsky S-42 , Martin M-130 and the Boeing 314 Clipper , the FE's role was referred to as an "engineer" (much like a ship's engineer) on the first very large flying boat, the Dornier Do X . On the Do X the FE operated a large and complex engineering station similar to later large transport aircraft to monitor

8748-440: The percentage of the total mass divided between these two particles vary from 100% P 1 and 0% P 2 through 50% P 1 and 50% P 2 to 0% P 1 and 100% P 2 , then the center of mass R moves along the line from P 1 to P 2 . The percentages of mass at each point can be viewed as projective coordinates of the point R on this line, and are termed barycentric coordinates . Another way of interpreting

8910-618: The Army Chief of Staff General George C. Marshall , General Dwight D. Eisenhower (to command Operation Torch for the invasion of North Africa), Deputy Chief of Staff of Army Ground Forces General Mark W. Clark , Operation Torch Air Force liaison officer Colonel Hoyt Vandenberg , Chief of the Navy's Bureau of Aeronautics Rear Admiral John Henry Towers , who oversaw Navy aircraft procurement and training, and presidential advisors W. Averell Harriman and Harry Hopkins who were crossing to negotiate

9072-617: The Atlantic to Natal in Brazil, and headed north to Belém , and from there with an additional fuel stop to Washington, D.C., arriving in time for the news of the raid to be made public. Many of the surviving members of the raid followed soon after in another Stratoliner. The North Atlantic ferry route was set up with help from former Arctic explorer Colonel Bernt Balchen , who assisted with Bluie East Two and Bluie East Eight in Greenland to reduce

9234-598: The Atlantic. By the time they were withdrawn, over 3000 trans-oceanic crossings had been made, and they had flown 21,284 while in USAAF service with the ICD. The sole accident occurred during night landing at Natal in Brazil when an undercarriage leg was torn off by a mound of dirt. It cost TWA about $ 2 million to have the five aircraft rebuilt by Boeing and the first of them resumed passenger service on April 1, 1945. The CAA recertified these as SA-307B-1 civilian airliners with their original registration numbers. On April 1, 1945,

9396-810: The B-17C mounted low on the fuselage to a constant chord center section faired to the fuselage, with four 1,100 hp (820 kW) Wright GR-1820 Cyclone air-cooled radial engines . TWA examples used GR-1820-G105A engines fitted with two stage superchargers for high altitude performance, while the Pan Am examples used the GR-1820-G102 with a single stage supercharger. Engine exhaust collector rings designed to reduce noise, and exhaust mufflers were installed. TWA aircraft were fitted with cowl flaps, to adjust engine cooling air, while Pan Am aircraft had fixed cowling rings without cowling gills. When operating in cooler conditions,

9558-494: The CAA for overland flights, which were served by a network of beacons across the continent, when the aircraft were not being flown by visual flight rules (VFR). Both T&WA and Pan Am normally carried two flight attendants. T&WA began using Hostesses (as they called them) as cabin crew in late 1935, while Pan Am continued to use male stewards until late in WW2. Following the entry of

9720-746: The FE sets and adjusts engine power during takeoff, climb, cruise, go-arounds, or at any time the pilot flying requests a specific power setting to be set during the approach phase. The FE sets and monitors major systems, including fuel, pressurization and air conditioning, hydraulic, electrics (engine driven generators, auxiliary power units ), gas turbine compressor/air turbine motor (APU, GTC, ATM), ice and rain protection (engine and nacelle anti-ice, window heat, probe heater), oxygen, fire and overheat protection of all systems, liquid cooling system, draw through cooling system, forced air cooling system, and powered flying controls. FEs are also responsible for preflight and postflight aircraft inspections, and ensuring that

9882-557: The Pan Am aircraft could be fitted with a blanking disk that covered part of the front of the engine. Both versions had sufficient power to maintain altitude on only two engines, one of the KLM requirements. Both used three bladed Hamilton Standard Hydromatic constant speed propellers, and new high octane fuels were developed to help the engines operate under the increased supercharger pressure. Both versions had trailing edge flaps controlled with electric motors, although SA-307B for T&WA and

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10044-534: The SA-307B-1s used the wings and elevators from the B-17G with split flaps, and 1,200 hp (890 kW) Cyclones. On most, but not all examples, the leading edges of the wings, horizontal stabilizer and fin were fitted with rubber expanding type de-icing boots, which would inflate and deflate repeatedly to break ice from the flying surfaces. All movable surfaces, including the rudder, ailerons and elevators had fabric over

10206-546: The SB-307B for Hughes featured slotted flaps with prominent external hinges, while the Pan Am examples had simpler split flaps with flush hinges, similar to those used on the B-17s. All of the fuel was carried in the wings, with a 212.5 US gal (804 L; 176.9 imp gal) tank mounted between the inboard nacelle and the fuselage, and a 425 US gal (1,610 L; 354 imp gal) main fuel tank as well as

10368-528: The South Atlantic, and between New York and Prestwick , Scotland, across the North Atlantic. They often flew non-stop the 2,122 mi (3,415 km) between Gander, Newfoundland and Prestwick, Scotland in the north, and the 2,500 mi (4,100 km) between Natal , Brazil and Accra , Ghana in the south. After July 1942 a refueling stop at Ascension Island was added in the South Atlantic. In

10530-410: The Stratoliner underpowered, and the climb suffered accordingly. The overloading burnt out engines and destroyed piston rings, but closely monitoring engine oil consumption often caught failures before they occurred. Passenger facilities were reduced to 4 bunks which when folded away allowed seating for 12, along with 4 seats along the opposite side of the aircraft. Removable tables were provided in

10692-490: The T&WA markings which had already been applied to their airframes were removed. T&WA filed a lawsuit against Boeing for default of contract, and Boeing sued T&WA for breach of contract over the non-payment. Hughes had begun secretly buying up T&WA shares and by March 1939, Hughes has a controlling interest in Trans-World Airlines (or TWA - as it was rebranded once he had taken over), with roughly 46% of

10854-601: The US Government gave export permission on the engines. After not hearing back, Boeing sent a new quote to KLM for $ 300,000 per aircraft, or $ 320,000 for the pressurized version December 20, 1938, the KLM board made the decision to order two four-engine aircraft, with consideration of the Boeing 307 and Focke Wulf Fw 200 Condor, however the Condor was not suitable for the East Indies route. Following T&WA defaulting on payments,

11016-509: The USAAF had amassed sufficient long range transports that it no longer needed the C-75s, and they sold the fleet back to TWA, who paid to have them converted back to civil standard under Boeing's SA-307B-1 designation. CAA concerns over cracks in the wing spar tubing led to the TWA Stratoliners getting new B-17G wings and horizontal tail, with the leading edge of the longer span, narrower chord horizontal stabilizer moved about 3 ft (0.91 m) to

11178-471: The United States into World War II in December 1941, long-range transports were needed to ferry government and military officials around the globe and many aircraft, including T&WA's Boeing 307s, were pressed into service. Beginning in February 1942, these were flown to Albuquerque, New Mexico for conversion, which included the removal of the plush, but heavy civilian fittings, including the massive mirrors in

11340-400: The air, which was then passed through radiator condensers to cool the air, and it was then run through channels to the vents in the cabin. External hookups allowed ground air conditioner units to cool the cabin air when the engines were off. The Stratoliners were normally flown with a pilot and co-pilot, and both Pan Am and T&WA aircraft carried a flight engineer to reduce the workload on

11502-422: The aircraft stalled and entered a spin. It made two to three turns before the pilot was able to stop the spin using the engines, however the ensuing high speed dive and the forces that resulted from attempting to pull up before hitting the ground, resulted in the left outer wing tearing off with one engine still attached, followed by the right wing, just outside the outer engine, both of which also tore off parts of

11664-512: The aircraft's FE is also authorised to make and certify repairs to the aircraft when it is away from its base. This can eliminate the need for technical repair crews to accompany the aircraft on short deployments. On civilian airplanes the FE is positioned so that they can monitor the forward instruments, pilot selections and adjust the thrust levers located on the centre pedestal; the FE's chair can travel forward and aft and it can swivel laterally 90 degrees, which enables them to face forward and set

11826-415: The airplane; instead, the FE's position had a specialized control panel allowing for the monitoring and control of various aircraft systems. The FE is therefore an integrated member of the flight deck crew who works in close coordination with the two pilots during all phases of flight. Traditionally, the FE station has been usually placed on the main flight deck just aft of the pilot and copilot, and close to

11988-432: The antenna being torn off, or lashing against the fuselage. An astrodome was fitted and the perspex top windows which produced excessive parallax were replaced with optically flat glass, to allow the navigator to take star shots (the angle between stars and the horizon could be used to determine how far north or south they were), necessary to determine their position when crossing large bodies of water. The SA-307B-1s retained

12150-421: The astrodomes when converted back from C-75 in 1944. To further aid navigation, a B-3 driftmeter was installed, along with an aperiodic compass that did not lag or lead in turns as a conventional compass does. Mae West life vests and life rafts were also provided. The landing gear was strengthened, and the maximum takeoff weight was increased from 45,000 to 56,000 lb (20,000 to 25,000 kg), leaving

12312-449: The cabin to lay out maps and do paperwork. The exterior was then camouflaged in standard USAAF colours, with olive drab upper surfaces and neutral grey undersides, and each aircraft had its name painted on the nose and over the cabin door, which would also be used by many later operators. The names had previously been used in TWA publicity, but not painted on the aircraft. After three years

12474-523: The carburetor heating themselves and the aircraft was repaired and returned to service. Boeing made claims both in their period advertising and in their current web site that it was the first high-altitude commercial transport, and the first with a flight engineer. However its first flight on December 31, 1938, was later than that of the Renard R-35 which also had a pressurized cabin for passengers, which flew on April 1, 1938, but it crashed, and development

12636-500: The case of a system of particles P i , i = 1, ...,  n   , each with mass m i that are located in space with coordinates r i , i = 1, ...,  n   , the coordinates R of the center of mass satisfy ∑ i = 1 n m i ( r i − R ) = 0 . {\displaystyle \sum _{i=1}^{n}m_{i}(\mathbf {r} _{i}-\mathbf {R} )=\mathbf {0} .} Solving this equation for R yields

12798-414: The center of mass is the particle equivalent of a given object for application of Newton's laws of motion . In the case of a single rigid body , the center of mass is fixed in relation to the body, and if the body has uniform density , it will be located at the centroid . The center of mass may be located outside the physical body , as is sometimes the case for hollow or open-shaped objects, such as

12960-488: The center of mass is the same as the centroid of the volume. The coordinates R of the center of mass of a two-particle system, P 1 and P 2 , with masses m 1 and m 2 is given by R = m 1 r 1 + m 2 r 2 m 1 + m 2 . {\displaystyle \mathbf {R} ={{m_{1}\mathbf {r} _{1}+m_{2}\mathbf {r} _{2}} \over m_{1}+m_{2}}.} Let

13122-406: The center of mass of a circular cylinder of constant density has its center of mass on the axis of the cylinder. In the same way, the center of mass of a spherically symmetric body of constant density is at the center of the sphere. In general, for any symmetry of a body, its center of mass will be a fixed point of that symmetry. An experimental method for locating the center of mass is to suspend

13284-493: The center of mass of the whole is the weighted average of the centers. This method can even work for objects with holes, which can be accounted for as negative masses. A direct development of the planimeter known as an integraph, or integerometer, can be used to establish the position of the centroid or center of mass of an irregular two-dimensional shape. This method can be applied to a shape with an irregular, smooth or complex boundary where other methods are too difficult. It

13446-502: The center of the Earth and the Moon, approximately 1,710 km (1,062 miles) below the surface of the Earth, where their respective masses balance. This is the point about which the Earth and Moon orbit as they travel around the Sun . If the masses are more similar, e.g., Pluto and Charon , the barycenter will fall outside both bodies. Knowing the location of the center of gravity when rigging

13608-460: The concept further. Newton's second law is reformulated with respect to the center of mass in Euler's first law . The center of mass is the unique point at the center of a distribution of mass in space that has the property that the weighted position vectors relative to this point sum to zero. In analogy to statistics, the center of mass is the mean location of a distribution of mass in space. In

13770-399: The coordinates R to obtain R = 1 M ∭ Q ρ ( r ) r d V , {\displaystyle \mathbf {R} ={\frac {1}{M}}\iiint _{Q}\rho (\mathbf {r} )\mathbf {r} \,dV,} Where M is the total mass in the volume. If a continuous mass distribution has uniform density , which means that ρ is constant, then

13932-623: The coordinates of the center of mass R * in the horizontal plane as, R ∗ = − 1 W k ^ × ( r 1 × F 1 + r 2 × F 2 + r 3 × F 3 ) . {\displaystyle \mathbf {R} ^{*}=-{\frac {1}{W}}\mathbf {\hat {k}} \times (\mathbf {r} _{1}\times \mathbf {F} _{1}+\mathbf {r} _{2}\times \mathbf {F} _{2}+\mathbf {r} _{3}\times \mathbf {F} _{3}).} The center of mass lies on

14094-551: The copilot becomes the PNF and the captain becomes the PF; one such example was on the A300 B-Series aircraft when there was a complete loss of generator-supplied electrical power, whereupon the standby instruments that were powered were on the captain's side only, requiring the captain to be PF and the PNF and FE to resolve the issue. During World War II many U.S. bomber aircraft incorporated

14256-522: The crossing, and the ICD C-75s would routinely lead flights of USAAF twin-engined aircraft, such as Douglas A-20s across. In November 1943, a C-75 carried Soong Mei-Ling , wife of the Chinese Nationalist warlord Chiang Kai-Shek , from Chungking to Washington to receive medical care and to negotiate military aid for China. Two main routes were flown, between Washington, D.C., and Cairo across

14418-436: The distinction between the center-of-gravity and the mass-center. Any horizontal offset between the two will result in an applied torque. The mass-center is a fixed property for a given rigid body (e.g. with no slosh or articulation), whereas the center-of-gravity may, in addition, depend upon its orientation in a non-uniform gravitational field. In the latter case, the center-of-gravity will always be located somewhat closer to

14580-440: The distributed mass sums to zero. For a rigid body containing its center of mass, this is the point to which a force may be applied to cause a linear acceleration without an angular acceleration . Calculations in mechanics are often simplified when formulated with respect to the center of mass. It is a hypothetical point where the entire mass of an object may be assumed to be concentrated to visualise its motion. In other words,

14742-438: The engine power, then move aft and rotate sideways to monitor and set the systems panel. The FE is the aircraft systems expert onboard and responsible for troubleshooting and suggesting solutions to in-flight emergencies and abnormal technical conditions, as well as computing takeoff and landing data. The FE's seat on modern aircraft has a complete range of motion (side to side, forward to aft, swivel, up and down) to accommodate

14904-483: The engines that was not needed for the simpler supercharger installation used on the Stratoliner, while one duct opening was retained on each wing between the engine nacelles, to provide additional cabin air. Further mods made by TWA included improved sound proofing and temperature control, and on March 15, 1945, the B-1 recertification tests were completed to the CAA's satisfaction. The estimated cost to repurchase and refurbish

15066-528: The equations of motion of planets are formulated as point masses located at the centers of mass (see Barycenter (astronomy) for details). The center of mass frame is an inertial frame in which the center of mass of a system is at rest with respect to the origin of the coordinate system . The concept of center of gravity or weight was studied extensively by the ancient Greek mathematician , physicist , and engineer Archimedes of Syracuse . He worked with simplified assumptions about gravity that amount to

15228-419: The fares slashed by a third. The first coach service, from New York La Guardia to Chicago via Pittsburgh was made on June 1, 1949, with a full load of 38 passengers. Centre of gravity In physics , the center of mass of a distribution of mass in space (sometimes referred to as the barycenter or balance point ) is the unique point at any given time where the weighted relative position of

15390-453: The first of 12 C-54s. and Pan Am would also supplement their Stratoliners with 12 C-54s. TWA received two C-54s in August and had 5 by September, and a full allotment of 12 by November, along with the first three C-87s, to supplement the C-75s. At the same time Curtiss C-46 Commandos , Douglas C-47s and C-53s provided feeder links to the C-75s, C-54s and C-87s, as their range was inadequate for

15552-430: The first post-war civil commercial flight was made by Zuni, now as a SA-307B-1, from La Guardia to San Francisco via Pittsburgh, Saint Louis, Kansas City, Albuquerque, and Burbank, but the second transcontinental flight did not happen until a month later, when on May 1, 1945, a flight was made from Washington, DC to Spokane, Washington, via Dayton Municipal Airport , St Louis, Kansas City, Albuquerque and Burbank, reflected

15714-460: The first three T&WA aircraft were offered to KLM in late 1939 but a quick decision was needed by Saturday, March 18, 1939, but KLM was unable to make that decision before the offer expired, and requested an extension. On March 21, 1939, KLM confirmed that they still planned to buy 307s and insisted that they were content with Boeing's progress. Ultimately though, KLM did not buy the 307s because their representatives' test flight insurance coverage

15876-407: The five aircraft was $ 2 million. Ten 307s were built. NC19906 was temporarily marked as NX1940 and NC1940 for publicity purposes. The first Boeing 307 Stratoliner, serial 1994, registration NX19901 , made its first flight from Boeing Field , near Seattle on December 31, 1938, prior to its intended delivery to Pan Am following testing and certification. As related above , it crashed on

16038-473: The force of the spin prevented their use. The crash delayed the program by over a year, beginning with a three-month investigation by the US Civil Aeronautics Authority , the precursor to the current Federal Aviation Administration , and Boeing to determine the causes. Flight and wind tunnel testing showed that both an extended dorsal fin and an enlarged vertical tail were needed to prevent

16200-432: The former reaching retirement age. Starting in the 1980s, the development of powerful and small integrated circuits and other advances in computers and digital technology eliminated the need for flight engineers on airliners and many modern military aircraft. On two-pilot flight deck airplanes, sensors and computers monitor and adjust systems automatically. There is no onboard technical expert and third pair of eyes. If

16362-405: The formula R = ∑ i = 1 n m i r i ∑ i = 1 n m i . {\displaystyle \mathbf {R} ={\sum _{i=1}^{n}m_{i}\mathbf {r} _{i} \over \sum _{i=1}^{n}m_{i}}.} If the mass distribution is continuous with the density ρ( r ) within a solid Q , then

16524-467: The highly polished fuselage was coated with soapy water while the fuselage pressurized, for workers to look for the bubbles that would indicate a leak, much like testing a bicycle inner tube. Before the first aircraft had rolled out, T&WA's chief engineer discovered that the extruded metal tubing used for the wing spars was defective, with stress corrosion cracks produced by cold rolling the tubing to increase tensile strength. Affected aircraft included

16686-423: The inboard flaps were also extended. The first several aircraft, including NC19902, NC19903, and NC19904 were all rolled out with the small tail and then modified later. Test flights resumed on May 19, 1939, after the changes had been incorporated, and on June 20, 1939, the first flight was made with the "supercharged cabin" pressurization system on. On March 13, 1940, Approved Type Certificate (ATC) number 719

16848-439: The integral of the weighted position coordinates of the points in this volume relative to the center of mass R over the volume V is zero, that is ∭ Q ρ ( r ) ( r − R ) d V = 0 . {\displaystyle \iiint _{Q}\rho (\mathbf {r} )\left(\mathbf {r} -\mathbf {R} \right)dV=\mathbf {0} .} Solve this equation for

17010-481: The last of their five was delivered on June 4, 1940. It was not their first four engine airliner, as one of their parent companies, Western Air Express had operated the Fokker F-32 . All five were named in TWA promotional material for North American Indigenous tribes - names that would be used throughout their careers, continuing long after they left TWA. War intervened in December 1941, and civil aircraft production

17172-404: The main attractive body as compared to the mass-center, and thus will change its position in the body of interest as its orientation is changed. In the study of the dynamics of aircraft, vehicles and vessels, forces and moments need to be resolved relative to the mass center. That is true independent of whether gravity itself is a consideration. Referring to the mass-center as the center-of-gravity

17334-422: The many positions required to monitor and operate the aircraft systems. The basic philosophy of a three-person flight deck in many flight operations, should an abnormality or emergency arise, is for the captain to hand over the actual flying of the aircraft to the first officer (co-pilot). The captain and FE together review and carry out the necessary actions required to contain and rectify the problem. This spreads

17496-512: The mass of the particle x i {\displaystyle x_{i}} for the center of mass or given a value of 1 for the geometric center: ξ i = cos ⁡ ( θ i ) ζ i = sin ⁡ ( θ i ) {\displaystyle {\begin{aligned}\xi _{i}&=\cos(\theta _{i})\\\zeta _{i}&=\sin(\theta _{i})\end{aligned}}} In

17658-470: The maximum landing weight rose to 47,000 lb (21,000 kg). Slots were re-incorporated into the wingtip leading edges, as they had been with the pre-war airliners. The cabin was redesigned and passenger capacity was increased from 33 to 38, with the cabin now divided into a 10-seat front section and a 28-seat rear section, with no sleepers. The cabin pressurization system was never re-installed. The B-17G wings came with turbo-supercharger ducting for

17820-419: The modified undercarriage, and in hard landings, easily exceeded the contract's minimum required 500 ft/m (46 m/ft) descent rate with a successful 800 ft/m (74 m/ft) landing descent. T&WA was also concerned about the engine carburetor intake heaters being deliberately restricted by Boeing to prevent cooking the engines, which could potentially leave crews unable to clear ice. Their point

17982-537: The north, stops at Iceland or Greenland were often necessary, when flying west against unusually strong prevailing winds. As Douglas C-54 Skymasters took over the Gander to Prestwick route, the C-75s operated between Marrakech and Prestwick over the Atlantic. ICD C-75s crossing the Atlantic had to be careful to avoid Allied convoys and German U-boats , to avoid being shot at. Cherokee was returning American troops from Reykjavik to Gander at 1,000 ft (300 m), and

18144-463: The object from two locations and to drop plumb lines from the suspension points. The intersection of the two lines is the center of mass. The shape of an object might already be mathematically determined, but it may be too complex to use a known formula. In this case, one can subdivide the complex shape into simpler, more elementary shapes, whose centers of mass are easy to find. If the total mass and center of mass can be determined for each area, then

18306-520: The object. The center of mass will be the intersection of the two lines L 1 and L 2 obtained from the two experiments. Engineers try to design a sports car so that its center of mass is lowered to make the car handle better, which is to say, maintain traction while executing relatively sharp turns. The characteristic low profile of the U.S. military Humvee was designed in part to allow it to tilt farther than taller vehicles without rolling over , by ensuring its low center of mass stays over

18468-741: The particles relative to the center of mass. Let the system of particles P i , i = 1, ..., n of masses m i be located at the coordinates r i with velocities v i . Select a reference point R and compute the relative position and velocity vectors, r i = ( r i − R ) + R , v i = d d t ( r i − R ) + v . {\displaystyle \mathbf {r} _{i}=(\mathbf {r} _{i}-\mathbf {R} )+\mathbf {R} ,\quad \mathbf {v} _{i}={\frac {d}{dt}}(\mathbf {r} _{i}-\mathbf {R} )+\mathbf {v} .} The total linear momentum and angular momentum of

18630-415: The point of being unable to rotate for takeoff or flare for landing. If the center of mass is behind the aft limit, the aircraft will be more maneuverable, but also less stable, and possibly unstable enough so as to be impossible to fly. The moment arm of the elevator will also be reduced, which makes it more difficult to recover from a stalled condition. For helicopters in hover , the center of mass

18792-413: The power had to be turned off before being used. A parking brake was provided, along with an emergency air brake system run off a bottle of compressed air, while the tailwheel was fully retractable. The fuselage was described as being dirigible shaped, and was an elongated teardrop, with a constant 11.5 ft (3.5 m) diameter tube lengthening it at its widest point. The circular section fuselage

18954-443: The pressurized cabin through specially developed glands designed to allow free movement of the cables, with a negligible amount of air leakage. The main cockpit windows were made from 5 ⁄ 8  in (16 mm) thick safety glass, while the rest of the windows were made of Plexiglass or Lucite sealed into rubber channels A large ram-air scoop on the cabin roof was provided to supply cooling air while at lower altitudes, and

19116-461: The process here is the mechanical balancing of moments about an arbitrary point. The numerator gives the total moment that is then balanced by an equivalent total force at the center of mass. This can be generalized to three points and four points to define projective coordinates in the plane, and in space, respectively. For particles in a system with periodic boundary conditions two particles can be neighbours even though they are on opposite sides of

19278-697: The prototype, the first Pan Am machine, and some early production B-17s, and resulted in T&WA having to have their engineers manually inspect every tube that was to be incorporated into their aircraft. The first aircraft completed, registration NX19901 , crashed on March 18, 1939. while being demonstrated after having been recently fitted with instruments to measure flight control forces. The Boeing 307 took off at 1257hrs (local time) from Boeing Field in Seattle with ten occupants, and they climbed to an altitude of 11,000 ft (3,400 m) where stability tests were made and while carrying out side-slips near Alder,

19440-431: The reaction board method is a static analysis that involves the person lying down on that instrument, and use of their static equilibrium equation to find their center of mass; the segmentation method relies on a mathematical solution based on the physical principle that the summation of the torques of individual body sections, relative to a specified axis , must equal the torque of the whole system that constitutes

19602-525: The rear, while more powerful versions of the same Wright Cyclone engines increased power from 1,100 to 1,200 hp (820 to 890 kW), but without the B-17G's turbosuperchargers. New propellers and landing gear were also installed. The change to the tailplane required that the structural bulkhead supporting the forward spar be moved aft, while the rear bulkhead was reworked and additional fuselage stiffeners were added. The tailwheel switched to using B-17G wheels and 26" smooth tread tires, which required that

19764-429: The reference point R is chosen so that it is the center of mass, then ∭ Q ρ ( r ) ( r − R ) d V = 0 , {\displaystyle \iiint _{Q}\rho (\mathbf {r} )\left(\mathbf {r} -\mathbf {R} \right)dV=0,} which means the resultant torque T = 0 . Because the resultant torque is zero the body will move as though it

19926-448: The rudder stalling in a yaw, and solutions were flight tested on NC19903 , including an intermediate solution consisting of just an extended dorsal fin. The resulting redesign was also incorporated into the redesign of the rear fuselage of the B-17E bomber. The wings were reinforced and Handley Page slots were added to the outer wing leading edges to improve low speed aileron control while

20088-401: The same. However, for satellites in orbit around a planet, in the absence of other torques being applied to a satellite, the slight variation (gradient) in gravitational field between closer-to and further-from the planet (stronger and weaker gravity respectively) can lead to a torque that will tend to align the satellite such that its long axis is vertical. In such a case, it is important to make

20250-408: The shares. By August 1939, TWA and Boeing had resumed negotiations so TWA would get five 307s, and Hughes would get one. The cost to TWA had risen, and was now $ 1,750,000 or $ 350,000 per aircraft - three times the cost for Douglas DC-3s. In early 1940, Hughes bought up all remaining outstanding TWA shares not otherwise reserved for employees. TWA received its first Stratoliner on May 6, 1940, and

20412-586: The sole four-engine commercial airliner in domestic service in the US. On July 10, 1939, TWA had signed a contract with Lockheed to develop the Constellation , which was to be capable of 5 miles/min (350 mph (560 km/h)) compared to the Stratoliner's 4 miles/min (246 mph (396 km/h)), but with production diverted to military for the duration of the war, the first TWA Constellations did not enter service until February 1946 and were soon grounded dealing with

20574-418: The space bounded by the four wheels even at angles far from the horizontal . The center of mass is an important point on an aircraft , which significantly affects the stability of the aircraft. To ensure the aircraft is stable enough to be safe to fly, the center of mass must fall within specified limits. If the center of mass is ahead of the forward limit , the aircraft will be less maneuverable, possibly to

20736-1500: The system are p = d d t ( ∑ i = 1 n m i ( r i − R ) ) + ( ∑ i = 1 n m i ) v , {\displaystyle \mathbf {p} ={\frac {d}{dt}}\left(\sum _{i=1}^{n}m_{i}(\mathbf {r} _{i}-\mathbf {R} )\right)+\left(\sum _{i=1}^{n}m_{i}\right)\mathbf {v} ,} and L = ∑ i = 1 n m i ( r i − R ) × d d t ( r i − R ) + ( ∑ i = 1 n m i ) [ R × d d t ( r i − R ) + ( r i − R ) × v ] + ( ∑ i = 1 n m i ) R × v {\displaystyle \mathbf {L} =\sum _{i=1}^{n}m_{i}(\mathbf {r} _{i}-\mathbf {R} )\times {\frac {d}{dt}}(\mathbf {r} _{i}-\mathbf {R} )+\left(\sum _{i=1}^{n}m_{i}\right)\left[\mathbf {R} \times {\frac {d}{dt}}(\mathbf {r} _{i}-\mathbf {R} )+(\mathbf {r} _{i}-\mathbf {R} )\times \mathbf {v} \right]+\left(\sum _{i=1}^{n}m_{i}\right)\mathbf {R} \times \mathbf {v} } If R

20898-615: The system to determine the complete center of mass. The utility of the algorithm is that it allows the mathematics to determine where the "best" center of mass is, instead of guessing or using cluster analysis to "unfold" a cluster straddling the periodic boundaries. If both average values are zero, ( ξ ¯ , ζ ¯ ) = ( 0 , 0 ) {\displaystyle \left({\overline {\xi }},{\overline {\zeta }}\right)=(0,0)} , then θ ¯ {\displaystyle {\overline {\theta }}}

21060-440: The system. This occurs often in molecular dynamics simulations, for example, in which clusters form at random locations and sometimes neighbouring atoms cross the periodic boundary. When a cluster straddles the periodic boundary, a naive calculation of the center of mass will be incorrect. A generalized method for calculating the center of mass for periodic systems is to treat each coordinate, x and y and/or z , as if it were on

21222-404: The tail as a result of the aileron cables pulling them against the fuselage, which then caused the aircraft to pancake into a forested area at 1317hrs. All ten aboard were killed, which included T&WA's representative, KLM's technical director, a Dutch Air Ministry representative, Boeing's test pilot, as well as their Chief Aerodynamicist and their Chief Engineer. Parachutes were available but

21384-590: The twelve engines. The first US military aircraft to include a FE was the Consolidated PBY which was introduced into naval service in 1936. The FE panel was located in the pylon between the fuselage and the wing. The FE did not have ignition, throttle and propeller controls, thus a person in the cockpit was also required to start the engines. During the war the Avro Lancaster and Handley Page Halifax bombers employed FEs, as these large aircraft employed only

21546-412: The two pilots, by monitoring the engines for any problems and fine tuning them, while they also controlled fuel consumption from each of the tanks to maintain the aircraft's fore-aft and lateral balance. Too much fuel used in one tank could result in the aircraft becoming uncontrollable. They also monitored other aircraft systems, including hydraulics and the cabin pressurization system. The Flight engineer

21708-472: The underside of the fuselage. Extensive use was made of the latest in sound proofing, and the Dynafocal engine shock mounts were designed to reduce vibrations from being felt by the passengers. The air conditioning system used both electrical and mechanical systems, which drew air in through vents in leading edge of each wing near the roots to bring outside air to two engine driven superchargers that compressed

21870-568: The usual teething problems encountered with a new type, from July 11 to September 20, 1946, while the Douglas DC-4s began arriving in 1946 in small numbers and the Douglas DC-6 similarly, from 1947. At the same time, due to strong competition from war-surplus non-sked flights operating cheaply purchased war-surplus Douglas C-54s , in May 1949 the Stratoliner's were downgraded to a coach-only service with

22032-442: The vertical line L , given by L ( t ) = R ∗ + t k ^ . {\displaystyle \mathbf {L} (t)=\mathbf {R} ^{*}+t\mathbf {\hat {k}} .} The three-dimensional coordinates of the center of mass are determined by performing this experiment twice with the object positioned so that these forces are measured for two different horizontal planes through

22194-430: The volume. In a parallel gravity field the force f at each point r is given by, f ( r ) = − d m g k ^ = − ρ ( r ) d V g k ^ , {\displaystyle \mathbf {f} (\mathbf {r} )=-dm\,g\mathbf {\hat {k}} =-\rho (\mathbf {r} )\,dV\,g\mathbf {\hat {k}} ,} where dm

22356-413: The weight and balance of the aircraft is correctly calculated to ensure the centre of gravity is within limits. On airplanes where the FE's station is located on the same flight deck just aft of the two pilots (all western three- and four-man deck airplanes), they also monitor an aircraft's flight path, speed, and altitude. A significant portion of their time is spent cross checking pilot selections. The FE

22518-493: The wheel well be enlarged, and structure supporting the tailwheel reinforced. The main undercarriage wheels, tires, tubes & brakes remained unchanged, although the legs themselves were strengthened. The fuselages were stripped to bare metal and rewired with a 24VDC 1800 amp system from the B-29 Superfortress , replacing the original 24VDC 800 amp system. Maximum weight was increased to 54,000 lb (24,000 kg) and

22680-420: The women's "charm room" and the pressurization system to save weight. The sound insulation was also stripped out leaving the cabin much noisier than it had been. The forward men's washroom, and two of the four forward compartments were replaced with five gravity fed 212.5 US gal (804 L; 176.9 imp gal) fuel tanks and a 45 US gal (170 L; 37 imp gal) oil tank fed with

22842-423: The workload and ensures a system of cross-checking which maximizes safety. The captain is the manager and decision maker (pilot not flying, PNF), the first officer, or co-pilot, is the actual flier of the aircraft (pilot flying, PF), and the FE reads the check-lists and executes actions required under the auspices of the captain. There can be occasions when the roles of the pilots during an emergency are reversed, i.e.

23004-617: Was FedEx Express when they retired the last of their 727s in 2013. FedEx continued to operate the DC-10 until the end of 2022, all of which were originally delivered with a flight engineer's station, however all examples that were still in the fleet had been converted to MD-10 standard, which provided for a two-crew cockpit. Boeing 307 The Boeing Model 307 Stratoliner (or Strato-Clipper in Pan American service, or C-75 in USAAF service)

23166-493: Was La Guardia, NY to Chicago, Illinois to Kansas City, Missouri to Albuquerque, New Mexico to Burbank California and the reverse. 1940 was the best year for TWA, with 50% increase in passenger traffic over 1939, but they were still running exclusively in the red. On September 9, 1940, a TWA Stratoliner from Chicago to New York set a commercial speed record flying the 778 mi (1,252 km) in two hours and 52 minutes at an average speed of 271.4 mph (436.8 km/h). and

23328-436: Was abandoned. As for employing a flight engineer, it was preceded in the US on a commercial aircraft by Maddux Air Lines Ford Trimotors , whose "Mate" had the same responsibilities as a flight engineer. Additionally, all German World War One Riesenflugzeug multi-engine bombers had flight engineers as they were integral to the specification. As built, the Stratoliner used the all-metal stressed-skin cantilever wings from

23490-467: Was also an Aircraft Maintenance Engineer (AME) and aside from operating the radio, which required training in Morse code , he was also responsible for all technical issues, and would carry out repairs and maintenance on the 307s. Pan Am aircraft had one additional crew member compared to T&WA aircraft. Because they made long overwater flights, they carried a navigator, who was not yet considered necessary by

23652-481: Was approached with the idea. A ceiling of at least 16,000 ft (4,900 m) was required to avoid summertime "chop" over the Rocky Mountains , and to allow the aircraft to fly around the thunderstorms that can sometimes block mountain passes, which meant a pressurized cabin would be the most comfortable for passengers on long flights. In 1935, Boeing then designed a four-engine airliner using components from

23814-466: Was assigned to the Pan Am Boeing 307s, allowing commercial deliveries to commence. A second ATC was issued for the TWA aircraft, number 726, due to the numerous differences between the Pan Am and T&WA aircraft. T&WA was concerned about excessive undercarriage stiffness from their experience with the test flights with the XB-17, which were to be modified for the airliner. T&WA flight tested

23976-411: Was covered for a replacement cost of $ 500,000, with hull coverage and passenger liability, carried by Aero Insurance Underwriters and Associated Aviation Underwriters, despite the fact that Boeing was offering to sell the aircraft to KLM for much less than that. Another company that Boeing was in discussions with was Australian National Airways , who they quoted $ 310,000 per Stratoliner, or $ 340,000 for

24138-569: Was fitted with extra fuel tanks and was ready for the first leg of the round-the-world attempt when Nazi Germany invaded Poland on September 1, 1939, causing the attempt to be cancelled. Hughes' aircraft was stored in Glendale, California for the duration of the war, prior to being converted into a flying condo. Hughes had the extra fuel tanks removed, and for around $ 250,000, he had it fitted with much more powerful Wright R-2600 engines for its transformation into "The Flying Penthouse", which included

24300-499: Was flown in July 1942 from London to Washington to meet with North American leaders, with the engines leaned out so much that the last leg of the trip was able to skip numerous stops, so that they ended up being in the air for 21 hours 16 minutes when they arrived in Washington. On July 10, 1942, Ascension Island 's airfield opened in South Atlantic, shortening the hazardous transatlantic leg enough that smaller aircraft could now make

24462-455: Was halted, preventing any further deliveries. TWA first service flight was chosen to be on July 8, 1940, to coincide with anniversary of TAT's 48 hour coast-coast service, which had used trains for night legs. TWA's Stratoliners flew between Los Angeles and New York , making three stops. TWA's Burbank - La Guardia flight via Chicago was 2 hours quicker than for a DC-3 (13:40 east and 15:38 west) with 3 stops in each direction. The main route

24624-490: Was initially set up at the crowded Washington Bolling Field but was soon transferred all of their operations to nearby Washington National Airport . Passengers continued to be loaded at Bolling Field, after flying the short hop from Washington National Airport. The first north Atlantic crossing was in March 1942, when a flight from Washington to Prestwick carried senior military and government officials to Europe, which included

24786-443: Was made when icing problems during a test flight on May 17, 1940, with NC19905, while carrying dignitaries in overcast conditions in the mountains resulted in three of the four engines failing, while the fourth was losing power, despite every measure being taken to clear the ice. This resulted in the aircraft making a belly landing in a field with a partially lowered undercarriage, just south of Lamar, Colorado . T&WA then modified

24948-492: Was of all metal construction, skinned with 24ST Alclad and capable of maintaining a cabin pressure equivalent to 8,000 ft (2,400 m) when flying at a 16,000 ft (4,900 m) altitude, and a 12,000 ft (3,700 m) cabin pressure when at 20,000 ft (6,100 m), with a maximum pressure difference of 2.5 lb/sq ft (12 kg/m ). The structure was designed with strength reserves so as to handle as much as 6 lb/sq ft (29 kg/m ), but

25110-470: Was provided with adjustable air conditioning vents, reading lights, and a call button. Nine additional seats were provided along the port side of the aircraft, while washrooms which doubled as dressing rooms were provided at both ends of the cabin. The rear washroom was for women and was named the "ladies charm room". Its walls were covered in heavy plate glass mirrors, and it contained in its 34 sq ft (3.2 m ) area two dressing tables, each with

25272-604: Was regularly used by ship builders to compare with the required displacement and center of buoyancy of a ship, and ensure it would not capsize. An experimental method to locate the three-dimensional coordinates of the center of mass begins by supporting the object at three points and measuring the forces, F 1 , F 2 , and F 3 that resist the weight of the object, W = − W k ^ {\displaystyle \mathbf {W} =-W\mathbf {\hat {k}} } ( k ^ {\displaystyle \mathbf {\hat {k}} }

25434-411: Was rejected, and KLM found Boeing's response to providing for the next of kin unsatisfactory, a disagreement that was not cleared up until after World War 2. The insurance coverage on the aircraft was sufficiently large that it had the insurance industry worried about fallout, and as was the norm at the time, neither passengers nor crew could get coverage from any insurance company, but the aircraft itself

25596-443: Was returned to Hughes. It languished unflown until August 1965, when it was damaged beyond repair by Hurricane Cleo , with only about 500 hours on the airframe. It was then bought for $ 69 by Kenneth W. London, who cut the damaged wings and tail off, built a hull under it, and installed a pair of V-8 engines to convert it into a houseboat which he named Londonaire . After various repossessions, deaths and failed sales later, it became

25758-488: Was shot at by a US Navy ship that left over 200 holes in the aircraft's tail, and which nearly severed the elevator controls. Many transatlantic trips were made at night, so the navigator could get good star sightings. By 1944 the USAAF had enough long range transports that it no longer needed the small number of C-75s it had, and sold the fleet back to TWA, with the aircraft being transferred between January 6, 1944, and December 19, 1944. On August 11, 1942, ICD had received

25920-451: Was shut off when the cabin was pressurized at higher altitudes. The cockpit was fitted with an autopilot, radios and a radio direction finder (RDF) for navigation. The noted industrial designer Raymond Loewy designed the passenger cabin, with furnishings provided by Marshall Field's . It was divided into four compartments, each with six deep comfortable reclining chairs which could be converted into 16 sleeping berths. Each compartment

26082-406: Was situated at the rear of the cabin, behind which was positioned the rear hemispherical pressure bulkhead. Up to 412 cu ft (11.7 m ) or 6,590 lb (2,990 kg) of baggage could be stowed under the floor of the cabin, both between the wing spars, and behind the rear spar, which was accessible in flight through a hatch in the cabin floor, or on the ground through three hatches on

26244-574: Was the only available landplane transport capable of transatlantic flights with any payload. Seaplanes were too slow and not numerous enough, while the Douglas C-54 Skymaster would not enter service until March 1942 and took months to be available in any numbers, aside from a few ad-hoc conversions from Consolidated B-24 Liberator bombers, the Consolidated C-87 Liberator Express would not be ready until September 1942, and

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