Forty-Seven Years in Aviation: A Memoir; Chapter 8: Advanced Flight Training
The well-worn cover and frontispiece of a 1945 Army Air Force Manual (below) is typical of such publications in the 1940s. It was not an exhaustive discussion of the airplane and its systems but was considered a guide for B-29 pilots training to be airplane commanders. (The operational details were covered in various Technical Orders, long since known as -1 manuals.) In contrast, the seven-week course at Randolph in 1956 was not intended to produce qualified B-29 pilots, much less airplane commanders; rather, it provided a transition from the B-25 to the larger and more complex airplanes we would fly as line pilots.
In the mid-1930s the Army Air Force foresaw the need for bigger, faster, long-range bombers. The Boeing company had a leg up on the competition due to their early research; working without a contract, Boeing had built and flown two experimental airplanes that provided a wealth of data regarding the design of a very large (for the time) bomber. The first was designated the Y1B-9A and was, if nothing else, ugly. The fat wings, open cockpits and little-wheel-in-the-back landing gear were state of the art bomber design in the 1930s. The Y1B-9A was powered by two 600 hp Pratt & Whitney radial engines, had a maximum gross weight of 14,320 pounds and cruised at 165 miles per hour.
The B-9 didn't get beyond the service test phase but it set the stage for the next prototype, the B-15. Air Corps reviewers were favorably impressed; the airplane was huge for the time (wingspan 149 feet, max takeoff weight 70,700 pounds and wings so thick there was room for crewmembers to perform minor engine repairs in flight) but before the project could proceed, the Army's emphasis had shifted to defensive capabilities and the B-15 went no further. The only one manufactured was converted to a cargo airplane, redesignated the XC-105 and put to use as a cargo hauler in the Caribbean during WW II. Aerial combat in the early days of the war over Europe made it clear that for bombers to be effective, defense was the name of the game. Boeing embarked on a lengthy series of radical design changes, a number of prototypes and a host of major modifications that resulted in the XB-29's maiden flight in September 1942. The new airplane, a direct descendant of the B-17 Flying Fortress, was aptly named the Superfortress.
And "super" it was: The fat, wide wings of its predecessors were replaced by long, narrow wings that enabled higher airspeed and increased range, with Fowler flaps to permit takeoffs and landings at lower speeds and shorter ground-run distances. The B-29 was also much larger and more powerful than the B-17, evidenced by the chart below:
The B-29 was the first bomber with pressurized crew compartments: one in the nose to accommodate the pilots, flight engineer, navigator, radio operator and bombardier; another in the rear of the airplane for the gunners. A tunnel above the fore and aft non-pressurized bomb bays provided for crew movement between these compartments. Defensively, the B-29 had four gun turrets -- two on top of the fuselage, two below -- each equipped with two .50 caliber machine guns, and a pair of .50 caliber guns in the tail. One of the more remarkable features of the B-29 was its computerized central fire control system, with which the gunner in the upper rear turret could allocate targets to the other three turrets to maximize the airplane's firepower. It was the first bomber designed to carry 20,000 pounds of bombs or -- sans bombs -- fly almost 6,000 miles. Unfortunately, the B-29 had an Achilles heel ... the four Wright R-3350, 2200-hp engines. These powerplants were rushed through production to meet the Army's demand that the B-29 be put into service ASAP, a situation that raised the specter of less-than-the-best quality control. In addition, Boeing had enclosed the engines in tight-fitting nacelles that boosted the airplane's aerodynamic efficiency, but the accompanying decrease in cooling air resulted in chronic overheating and frequent engine failures. Maintaining cylinder head temperatures at safe levels was so critical that the procedure was addressed specifically in the Airplane Commander's Training Manual:
Cowl flaps, which are 15° open as the ship takes the runway, are closed to 7-1/2° by the time the airplane leaves the ground. This setting permits rapid acceleration of airspeed and should keep all cylinder-head temperatures below 260°. If cylinder-head temperatures rise above 260° on takeoff, or stay above 248° after the second power reduction, the flight engineer informs the airplane commander. The airplane commander can then order cowl flaps on the hot engine opened to a maximum of 10°. (Never open cowl flaps more than 10° in flight. Larger openings provide little, if any, additional cooling and reduce cruising ranges considerably.) Or, the airplane commander can pull back the throttle on the hot engine to about 25". The throttle should not be pulled back unless the airplane has reached 170 mph.The problem didn't go away until after the war, when Boeing turned 200-plus B-29s into B-50s by installing Pratt & Whitney R-4360 engines. Our short course at Randolph in 1956 may have been a "dying on the vine" combination of SAC's Combat Crew Training and a more generally oriented four-engine transition program for pilots who would subsequently fly prop-driven tankers and cargo/passenger airplanes. (The B-47 jet bomber entered service in 1951 and put the Superfortress out to pasture.) The academic schedule called for a total of 113 hours of classroom work, including crew management (there's a subject we hadn't studied before), more schooling in instrument techniques and weather, and many hours getting familiar with B-29 systems, most of which were similar to those we would encounter in other large airplanes.
The B-29 was virtually an all-electric airplane that required seven generators to handle the load ... one generator on each inboard engine, two on each of the outboards and an internal auxiliary power unit (APU) powered by a small gasoline engine. Management of the electrical and fuel distribution systems plus engine controls and indicators created the need for a full-time flight engineer and a dedicated control station located directly behind the copilot ... the engineer flew backwards. The engineer was responsible for starting the engines and maintaining proper operation of all systems throughout the flight.
I was familiar with the B-29's streamlined, all-glass nose that made the airplane resemble a torpedo with wings and a tail, but I was not prepared for the unique configuration of the cockpit viewed from the inside. Because of the circular cross-section of the fuselage and the need for access to the bombardier's station in the nose, the typical instrument panel and center console gave way to a completely different control arrangement on the flight deck. The pilot's throttles were located on the sub-panel to his left and the copilot's throttles were in the same position on his right. Both pilots and the engineer had access to a duplicate set of propeller control switches, but the remaining engine controls and a third set of throttles were located at the flight engineer's station. Cooperation between pilot and engineer was perhaps the most important thing we learned in this transition course ... the pilot flies the airplane but the engineer makes it run. For whatever reason the B-29 was not equipped with nosewheel steering, which made taxiing a rather delicate procedure. We were taught to use brakes (gently, gently!) rather than differential power; cylinder head temperatures tended to rise when the engines were operated at more than the standard 700 RPM idle setting. Engine runup prior to takeoff was routine, including a full-power check on each engine to confirm proper operation of the superchargers. Our training missions began at a nominal takeoff weight of 120,000 pounds. Once lined up on the runway, directional control was maintained by walking the throttles forward slowly to full power; if you became good at it you could keep the airplane on the centerline without using brakes. The rudder became effective at about 60 mph and the lift-off speed for this weight was 124 mph. With the standard flap setting of 25 degrees, standard-day conditions and no wind, the calculated takeoff distance was about 5,000 feet; 3500 feet on the runway, another 1500 feet in the air to clear a 50-foot obstacle. A skyrocket the B-29 was not; average climb rate was in the neighborhood of 1000 feet per minute. All three airplanes I had flown to this point (Piper Cub, T-6 and B-25) had rather short, fat wings that required only moderate rudder pressure to overcome adverse yaw. The B-29 was a different animal in this regard because of its high-aspect-ratio wing; lacking boosted controls, a lot of rudder pressure was required to make coordinated turns and fly a stable platform in turbulence. In short, a considerable amount of physical strength was required to fly the airplane properly. Our flight training amounted to 40 hours, split 50-50 between pilot and co-pilot time. The air work included instrument procedures; low-frequency range orientation and approaches, ADF exercises, and an introduction to the VOR, the newest wrinkle in IFR flying. We also had an opportunity to experience the two fairly-new precision approach systems, GCA and ILS. Simulated engine-out drills were conducted frequently (so what else was new in a multi-engine training program?) as well as a number of actual occurrences; one of my classmates experienced seven actual engine failures on the eight missions he flew ... Wright 3350s doing their thing. Given the propensity for engine failures, it was comforting to know the B-29 was flyable on three engines in the landing configuration, and could maintain altitude with only two engines operating, albeit at a lower weight.
Every airplane is restricted from executing certain maneuvers and the B-29 was no exception, but this illustration in the 1945 Airplane Commander Training Manual may have been a bit of overkill; no pilot in his right mind would attempt any of these. By mid-April I had filled enough squares to graduate from the Combat Crew Training/Four-Engine Transition Course (call it what you will) and we prepared to move on to my next assignment, as a tanker pilot in the Strategic Air Command at MacDill Air Force Base in Tampa, Fla. (My thanks to 56-I classmates Ev Chambers, Chris Menadier and Ed VanAkin, whose memories of our tour at Randolph AFB were sometimes stronger than mine.) [Continued next month.]