Question Mark ("?") was a modified Atlantic-Fokker C-2A transport airplane of the United States Army Air Corps. In 1929, commanded by Major Carl A. Spaatz, it was flown for a flight endurance record as part of an experiment with aerial refueling. Question Mark established new world records in aviation for sustained flight (heavier-than-air), refueled flight, sustained flight (lighter-than-air), and distance between January 1 and January 7, 1929, in a nonstop flight of 151 hours near Los Angeles, California.
Following the record-setting demonstration, the C-2A was returned to transport duties. In 1931, more powerful engines replaced those used in the endurance flight and it was redesignated as a C-7 transport. The aircraft was damaged beyond economical repair in 1932, when it crash-landed in Texas after running out of fuel, and was scrapped.
The flight demonstrated the military application of the concept, but while it inspired numerous efforts to set even greater endurance records, development of a practical in-flight refueling system was largely ignored by the world's air forces before World War II. Civilian development of aerial refueling in Great Britain was more successful, but in the end, it, too, was disregarded. However, Spaatz, two decades after the flight of the Question Mark, became head of the United States Air Force and using the British system as a starting point, implemented in-flight refueling on a worldwide operational basis.
Background The first complete in-flight refueling between two aircraft took place on June 27, 1923,While they had passed minor amounts of fuel in practice, the June 27 flight was the first aerial refueling mission, an attempt to set an endurance mark. when two Boeing-built de Havilland DH-4Bs of the United States Army Air Service accomplished the feat over San Diego's Rockwell Field. Subsequently, the same group of airmen established an endurance record of remaining aloft for more than 37 hours in August 1923, using nine aerial refuelings. In June 1928, a new endurance record of more than 61 hours was established in Belgium by Adjutant Louis Crooy and Sgt. Victor Groenen, also using aerial refueling.
Second Lt. Elwood R. Quesada, an engineer of the U.S. Army Air Corps stationed at Bolling Field in Washington, DC, nearly crashed from lack of fuel in April 1928 while participating in a long-range rescue mission to Labrador. Working with a U.S. Marine Corps aviator from Anacostia Naval Air Station, he devised a plan to break the Belgians' record using aerial refueling.According to the January 14, 1929 Time magazine, in addition to Crooy and Groenen's air-refueled record, an endurance record of 65 hours 31 minutes had been set in 1928 by a pair of Germans, Johann Risticz and Wilhelm Zimmerman, but they had not refueled during the flight. Quesada submitted the plan to Capt. Ira C. Eaker, an aide to Assistant Secretary of War for Air F. Trubee Davison, who had also been on the April mission. Their mutual interest in air-to-air refueling led Eaker to forward it to Maj. Gen. James E. Fechet, Chief of the Air Corps. Both Fechet and Davison approved the project on the condition that it demonstrate a military application and not just as a publicity stunt. Overall command of the project was given to Major Carl A. SpaatzIn 1929, the legal spelling of his name was "Spatz". the Assistant G-3 for Training and Operations in Fechet's office, who was on orders to take command of the 7th Bombardment Group at Rockwell Field.
Preparations
Aircraft modification A new Atlantic-Fokker C-2A transport, serial number 28-120, was selected for the project. Assigned to the Air Corps Detachment, Bolling Field at Bolling Field, it was flown to Middletown Air Depot, Pennsylvania, for modifications.Joe Baugher, 1922–1929 USAAS Serial Numbers The C-2A was an American-built military version of the Fokker F.VIIa-3m Trimotor, a high-wing monoplane with a gross weight of , re-engined with three Wright R-790 motors producing each. A C-2 variant nicknamed the Bird of Paradise had made the first transpacific flight to Hawaii the year before and proven the capability of the design. The C-2A had an internal fuel capacity of in a pair of wing tanks, and for the project, two tanks were installed in the cargo cabin. A hatch was cut in the roof of the C-2 behind the wing for transfer of the fuel hose and passage of supplies from the tanker to the receiver. The 72-octane aviation gasoline would be received in increments of about 90 seconds' duration.National Aviation Hall of Fame, Carl A. Spaatz biography
A tank was used to provide engine oil to the three motors, replenished by in-flight deliveries of cans of Pennzoil triple-extra-heavy lowered on slings. A copper tubing system was installed in an attempt to adequately lubricate the rocker arms of the engines in-flight. Doorways were cut on each side of the cockpit and catwalks built on the wings to enable mechanic Roy Hooe to access the engines for emergency maintenance. To reduce propeller noise, the two wing engines were mounted with Westinghouse twin-blade Micarta propellers, while the nose engine used a Standard three-blade steel propeller.
As word of the project spread, its members were continually being asked how long they expected to remain aloft. Their responses were generally to the effect: "That is the question." A large question mark was painted on each side of the fuselage to provoke interest in the endurance flight, prompting the nickname of the plane.
To deliver the fuel, two Douglas C-1 single-engine transports were also modified, s/n 25-428 designated "Refueling Airplane No. 1" and s/n 25-432 as "Refueling Airplane No. 2". The biplane C-1s were evolved from the Douglas World Cruiser design, with the pilots side-by-side in an open cockpit forward of the wing. Two tanks were installed in their cargo compartments, attached to a lead-weighted length of fire hose. The nozzle of the hose had a quick-closing valve on the tanker's end and was tightly wrapped with copper wire, one end of which could be attached to a corresponding copper plate mounted in Question Mark to ground the hose. The C-1s would each carry a third crewman in the cargo compartment to reel out the hose, lower a supply rope, and work the shutoff valve.
Planning The operation was scheduled to begin Tuesday, January 1, 1929, at Los Angeles, California, to take advantage of weather conditions and to generate publicity while refueling by overflying the 1929 Rose Bowl football game played that day in Pasadena. The refueling planes were based at each end of a 110-mi-long racetrack oval flight path, one at Rockwell Field and the other at the Metropolitan Airport, now Van Nuys Airport. The flight would originate and terminate there for any endurance record to be officially recognized by the Fédération Aéronautique Internationale.
Van Nuys was chosen over an existing dirt-strip airfield, Mines Field, located at El Segundo, because the weather in Van Nuys was considered more reliable and predictable, particularly in regard to temperature inversions and smog. Metropolitan was also an operational facility, while Mines Field had just been procured by the City of Los Angeles for use as a commercial airport. The project arrived there in December 1928 to begin preparations for the flight, with Capt. Hugh M. Elmendorf in charge of logistics and maintenance.
Because of weight considerations and the unreliability of radios, none was installed in the Question Mark. All communications between the aircraft or between Question Mark and the ground had to be accomplished using flags, flares, flashlights, weighted message bags, notes tied to the supply lines, or messages written in chalk on the fuselages of PW-9D fighters, painted black and nicknamed "blackboard planes". (One such message written on the side of a 95th Pursuit Squadron is externally linked below.) The first message delivered by chalked message was: "Don't forget Rose Bowl". (Maurer, p. 263)
Six days in the air
Crews The crew of Question Mark consisted of Spaatz, Eaker, Quesada, 1st Lt. Harry A. Halverson, and Sgt. Roy W. Hooe. Refueling Airplane No. 1 (at Rockwell) was crewed by pilots Capt. Ross G. Hoyt and 1st Lt. Auby C. Strickland, with 2nd Lt. Irwin A. Woodring reeling the hose. Refueling Airplane No. 2 (at Van Nuys) was crewed by pilots 1st Lt. Odas Moon and 2nd Lt. Joseph G. Hopkins, and hose handler 2nd Lt. Andrew F. Solter.
Four pilots of the 95th Pursuit Squadron, based at Rockwell Field, flew the PW-9 "blackboard planes": 1st Lt. Archie F. Roth, and 2nd Lts. Homer W. Kiefer, Norman H. Ives, and Roger V. Williams.
Takeoff and refueling Question Mark took off from Van Nuys at 7:26 am on New Year's Day 1929 with Eaker at the controls, carrying only of fuel to save takeoff weight. Aboard the Question Mark, either Halverson or Quesada did most of the piloting during cruising flight while Eaker monitored the throttles for smoothest engine performance. A log was kept by the flight officer (co-pilot) and dropped to the ground daily, and Eaker was responsible for winding the barograph, an instrument that continuously recorded altitude and time as documentary evidence for the records.
Less than an hour later, Moon completed the first refueling over Van Nuys. During refuelings, Eaker and Halverson manned the controls, Spaatz and Quesada supervised the fuel exchange, and Hooe operated a "wobble" pump. The C-1 approached the Question Mark from above and behind, maintaining 20 to of vertical separation, until in a position slightly ahead of the C-2. Both aircraft stabilized in level flight at and the hose was reeled out. Spaatz climbed on a platform below the open hatch, and wearing rain gear and goggles for protection against fuel spills, grounded the hose and then placed it in a receptacle mounted in the upper fuselage.
Made from a bucket with a sloped floor, the receptacle had connections to the two extra fuel tanks, and at Spaatz's signal, Solter opened the valve. Fuel flowed by gravity into the bucket at per minute and then into the tanks, where it was then pumped by hand into the wing tanks by Hooe. Food, mail, tools, spare parts, and other supplies were also passed by rope in the same fashion.
Sustaining flight The five men aboard Question Mark underwent medical examinations before the flight, and their flight surgeon planned a special diet. However, an electric stove to heat food was eliminated to save weight, and hot meals were sent aloft by the refuelers, including a turkey dinner on New Years Day prepared by a church in Van Nuys. The crew warded off boredom by reading, playing cards, sleeping in bunks mounted over the fuel tanks, and writing letters. After the existing endurance record was surpassed on Thursday evening, January 3, the support crew sent up cheese, figs, olives, and five jars of caviar for an in-flight celebration.On the other hand, when Spaatz's wife Ruth pointed out the aircraft passing overhead to their seven-year-old daughter Tattie after it had set the new record, rather than being impressed, the child reportedly said, "I think it's kind of dumb." (Davis, p. 22)
During a refueling,Bakse (p. 53, quoting Eaker) and Davis place this incident while the Question Mark was refueling over the Rose Bowl game on the afternoon of January 1. Boyne (p. 70) and Maurer (p. 262), using the flight record, place it just after midnight January 2. Spaatz was drenched with fuel when turbulence caused the hose to pull out of the receptacle. Recalling the event in 1975, Eaker said:We went over the Rose Bowl. It was very bumpy, as you can appreciate, as we should have appreciated, up against those mountains in January, and the refueling plane and the Question Mark were torn apart. I was piloting the Question Mark and I realized that General Spaatz had probably been drenched in high-octane gasoline.