Renato Donati prepares for high altitude flight, 11 April 1934. (Società Italiana Caproni Milano)
11 April 1934: Commander Renato Donati of Italy’s Regia Aeronautica flew a modified Società Italiana Caproni Milano Caproni Ca.113 two-place biplane named Alta Quota from Montecielo Airport, outside Rome, to a Fédération Aéronautique Internationale (FAI) World Record altitude of 14,433 meters (47,352 feet).¹
At such high altitudes, airman must not only be provided with oxygen, but it must be under positive pressure. In this photograph, Commander Donati is being prepared for the flight with a special pressurized suit made of “gutta percha” (a type of rubberized fabric).
Renato Donati in the cockpit of the Caproni Ca.114, 11 April 1934. (Società Italiana Caproni Milano)
The Chicago Daily Tribune reported:
ROME, April 11.—Renato Donati, 40 year old Italian war ace, hung up a world’s altitude record today when he spiraled his specially constructed Caproni airplane nine miles up into the skies of Rome, to the very limit of the earth’s air envelope.
Seventy-five minutes after he took off from the Monticello airport on his Icarian adventure Donati dropped back onto the field. He collapsed from the nervous and physical shock of such a swift change of atmospheric conditions, for his instruments registered a height of 14,500 meters [47,560 feet] and temperature of 66 degrees below zero, Centigrade [67.3 degrees below zero Fahrenheit]. With medical aid Donato quickly recovered. . .
—Chicago Daily Tribune, Volume XCIII.—No. 88, Thursday 12 April 1934, Page 11, column 1. Article written by David Darrah, Chicago Tribune Press Service.
Renato Donati after his world record-setting flight, 11 April 1934.
The Società Italiana Caproni, Milano Caproni Ca. 113 Alta Quota was developed from the Ca.113 trainer. It was powered by a British-built Bristol Pegasus, the same type used by the Houston Mount Everest Flying Expedition to fly over Mount Everest the previous week. It was an air-cooled, supercharged, 1,752.79-cubic-inch-displacement (28.72 liter) nine-cylinder radial engine, with a compression ratio of 5.3:1. It had a Normal Power rating of 525 horsepower at 2,000 r.p.m. at 11,000 feet (3,353 meters), and produced a maximum of 575 horsepower at 2,300 r.p.m. at 13,000 feet (3,962 meters). It drove a four-blade ground-adjustable metal propeller.
Caproni Ca.113 Alta Quota at Montecelio airport, 11 April 1934. (Luce Cinecittà)
The production Ca.113 was a single-engine, two-place, two-bay biplane with fixed landing gear, built in Italy and at Caproni’s subsidiary in Bulgaria. The airplane was designed to be aerobatic. It first flew in 1931. It was constructed of steel tubing and wood, covered wit aluminum sheet and doped fabric. The Ca.113 was 24 feet, 5 inches (7.442 meters) long with a wingspan of 34 feet, 5 inches (10.490 meters) and height of 9 feet, 2 inches (2.794 meters). The lower wing was staggered behind the upper. It had an empty weight of 1,797 pounds (815 kilograms) and gross weight of 2,348 pounds (1,065 kilograms).
The Ca.113 was powered by an Alfa-Romeo engine developed from the license-built Bristol Pegasus. It had a Normal Power rating of 525 horsepower at 2,000 r.p.m. at 11,000 feet (3,353 meters), and produced a maximum of 575 horsepower at 2,300 r.p.m. at 13,000 feet (3,962 meters).
The Ca.113 had a maximum speed of 143 miles per hour ( kilometers per hour), and was capable of climbing to 13,000 feet (3,962 meters) in 15 minutes.
The following year, Commander Donati’s Ca.114 (Ca.113 R, equipped with an Alfa Romeo Pegasus S.2 engine) was flown by aviatrix Contessa Carina Negrone, to a women’s record altitude of 12,043 meters (39,511 feet).²
Lockheed NF-104A Aerospace Trainer 56-756, with its Rocketdyne engine firing during a zoom-climb maneuver. (U.S. Air Force)
6 December 1963: Air Force test pilot Major Robert W. Smith takes the Lockheed NF-104A Aerospace Trainer, 56-0756, out for a little spin. . .
Starting at 0.85 Mach and 35,000 feet (10,668 meters) over the Pacific Ocean west of Vandenberg Air Force Base, California, Bob Smith turned toward Edwards Air Force Base and accelerated to Military Power and then lit the afterburner, which increased the General Electric J79-GE-3B turbojet engine’s 9,800 pounds of thrust (43.59 kilonewtons) to 15,000 pounds (66.72 kilonewtons). The modified Starfighter accelerated in level flight. At Mach 2.2, Smith ignited the Rocketdyne LR121 rocket engine, which burned a mixture of JP-4 and hydrogen peroxide. The LR121 was throttleable and could produce from 3,000 to 6,000 pounds of thrust (13.35–26.69 kilonewtons).
When the AST reached Mach 2.5, Smith began a steady 3.5G pull-up until the interceptor was in a 70° climb. At 75,000 feet (22,860 meters), the test pilot shut off the afterburner to avoid exceeding the turbojet’s exhaust temperature (EGT) limits. He gradually reduced the jet engine power to idle by 85,000 feet (25,908 meters), then shut it off. Without the engine running, cabin pressurization was lost and the pilot’s A/P22S-2 full-pressure suit inflated.
The NF-104A continued to zoom to an altitude where its aerodynamic control surfaces were no longer functional. It had to be controlled by the reaction jets in the nose and wing tips. 756 reached a peak altitude of 120,800 feet (36,820 meters), before reentering the atmosphere in a 70° dive. Major Smith used the windmill effect of air rushing into the intakes to restart the jet engine.
Lockheed NF-104 Aerospace Trainer zoom-climb profile. (U.S. Air Force via NF-104.com)
Major Smith had set an unofficial record for altitude. Although Lockheed had paid the Fédération Aéronautique Internationale (FAI) license fee, the Air Force had not requested certification in advance so no FAI or National Aeronautic Association personnel were on site to certify the flight.
For this flight, Robert Smith was nominated for the Octave Chanute Award “for an outstanding contribution made by a pilot or test personnel to the advancement of the art, science, and technology of aeronautics.”
Major Robert W. Smith, U.S. Air Force, with a Lockheed F-104 Starfighter. (U.S. Air Force)
Robert Wilson Smith was born at Washington, D.C., 11 December 1928. He was the son of Robert Henry Smith, a clerk (and eventually treasurer) for the Southern Railway Company, and Jeanette Blanche Albaugh Smith, a registered nurse. He graduated from high school in Oakland, California, in 1947. Smith studied at the University of California, Berkeley, and George Washington University.
Robert W. Smith joined the United States Air Force as an aviation cadet in 1949. He trained as a pilot at Goodfellow Air Force Base, San Angelo, Texas, and Williams Air Force Base in Arizona. He was commissioned as a second lieutenant, United States Air Force, 23 June 1950.
Second Lieutenant Robert Wilson Smith married Ms. Martha Yacko, 24 June 1950, at Phoenix, Arizona.
Lieutenant Robert W. Smith and his crew chief, Staff Sergeant Jackson, with Lady Lane, Smith’s North American F-86 Sabre. (Robert W. Wilson Collection)
He flew the F-86 Sabre on more than 100 combat missions with the 334th and 335th Fighter Interceptor Squadrons of the 4th Fighter Interceptor Wing during the Korean War. he named one of his airplanes Lady Lane in honor of his daughter. Smith was credited with two enemy aircraft destroyed, one probably destroyed and three more damaged.
Smith graduated from the Air Force Test Pilot School at Edwards Air Force Base in 1956. He flew more than fifty aircraft types during testing there and at Eglin Air Force Base, Florida. In 1962 he was assigned to the Aerospace Research Test Pilots School at Edwards for training as an astronaut candidate for Project Gemini.
Lieutenant Colonel Robert W. Smith, United States Air Force
After the NF-104A project was canceled, Lieutenant Colonel Smith volunteered for combat duty in the Vietnam War. He commanded the 34th Tactical Fighter Squadron, 388th Tactical Fighter Wing, at Korat Royal Thai Air Force Base, Thailand, flying the Republic F-105D Thunderchief. Bob Smith was awarded the Air Force Cross for “extraordinary heroism” while leading an attack at Thuy Phoung, north of Hanoi, 19 November 1967.
He had previously been awarded the Silver Star, and five times was awarded the Distinguished Flying Cross. Lieutenant Colonel Smith retired from the Air Force on 1 August 1969 after twenty years of service.
Lieutenant Colonel Robert Wilson Smith died at Monteverde, Florida, 19 August 2010. He was 81 years old.
Lockheed F-104A Starfighter 56-756 following a landing accident at Edwards AFB, 21 November 1961. (U.S. Air Force via the International F-104 Society)
56-756 was a Lockheed F-104A-10-LO Starfighter. Flown by future astronaut James A. McDivitt, it had been damaged in a landing accident at Edwards following a hydraulic system failure, 21 November 1961. It was one of three taken from storage at The Boneyard at Davis-Monthan Air Force Base, Tucson, Arizona, and sent to Lockheed for modification to Aerospace Trainers (ASTs). These utilized a system of thrusters for pitch, roll and yaw control at altitudes where the standard aerodynamic control surfaces could no longer control the aircraft. This was needed to give pilots some experience with the control system for flight outside Earth’s atmosphere.
Lockheed NF-104A Aerospace Trainer 56-756. (U.S. Air Force)
The F-104A vertical fin was replaced with the larger fin and rudder from the two-place F-104B for increased stability. The wingspan was increased to 25 feet, 11.3 inches (7.907 meters) for installation of the hydrogen peroxide Reaction Control System thrusters. The fiberglass nosecone was replaced by an aluminum skin for the same reason. The interceptor’s radar and M61 Vulcan cannon were removed and tanks for rocket fuel and oxidizers, nitrogen, etc., installed in their place. The fuselage “buzz number” was changed from FG-756 to NF-756.
The standard afterburning General Electric J79-GE-3B turbojet engine remained, and was supplemented by a Rocketdyne LR121 liquid-fueled rocket engine which produced 3,000 to 6,000 pounds of thrust (13.35–26.69 kilonewtons) with a burn time of 105 seconds.
56-756 was damaged by inflight explosions in 1965 and 1971, after which it was retired. It is mounted for static display at the Air Force Test Pilot School, Edwards Air Force Base, California, marked as 56-760.
Lockheed NF-104 Aerospace Trainer 56-756, marked as 56-760, on display at Edwards Air Force Base. (Kaszeta)
First Lieutenant John A. Macready dressed for high altitude flight. (U.S. Air Force)Captain John Arthur Macready, Air Service, United States Army, circa 1918. (U.S. Air Force)
28 September 1921: At McCook Field, Ohio, First Lieutenant John Arthur Macready, Air Service, United States Army, flew a turbo-supercharged Packard Lepère L USA C. II biplane, serial number S.C. 40015, to a world record altitude of 40,800 feet (12,436 meters). However, the official Fédération Aéronautique Internationale (FAI) is 10,518 meters (34,518 feet.)¹ He won his first of three Mackay Trophies for this flight.
John A. Macready graduated from Stanford University in 1913 with a degree in economics. He enlisted in the Aviation Section, Signal Corps, U.S. Army, as a Private 1st Class, 16 July 1917. On 27 December 1917, he was commissioned as a 1st lieutenant in the Aviation Section, Signal Officers Reserve Corps. Lieutenant Macready became a flight instructor at Brooks Field, Texas, where he wrote the standard instructional text. On 11 October 1918, Lieutenant Macready was promoted to the rank of captain. After World War I, he became an engineering test pilot at McCook Field near Dayton, Ohio. He reverted to his permanent rank of first lieutenant, 18 September 1920. In 1923, Macready graduated from the Aeronautical Engineer Course, Air Service Engineering School.
For six years John Macready was responsible for testing turbosuperchargers, which enabled aircraft engines to produce continuous power at increasing altitudes. It was while testing these that he established his altitude record.
Lt. John A. Macready with his Packard Lepère L USA C.II. (San Diego History Center)
During a 35 hour, 18 minute endurance flight at Rockwell Field, San Diego, California, 5–6 October 1922, John Macready and Oakley G. Kelly pioneered the use of inflight refueling from another aircraft. Also, he and Kelly made the first non-stop transcontinental flight when they flew a Fokker T-2 across the United States from Roosevelt Field, Long Island, New York, to Rockwell Field in 26 hours, 50 minutes, 38.6 seconds, 2–3 May 1923. Macready won his second and third Mackay Trophies for these achievements. He is the only man to have won it three times.
The Packard Lepère L USA C.II was a World War I biplane designed by French aeronautical engineer Captain Georges Lepère and built by the Packard Motor Car Company of Detroit, Michigan. It was to have been a two-place fighter, light bomber and observation aircraft armed with four machine guns.
The Packard Lepère was 25 feet, 3-1/8 inches (7.699 meters) long. The upper and lower wings had an equal span of 41 feet, 7¼ inches (12.681 meters), and equal chord of 5 feet, 5¾ inches (1.670 meters). The vertical gap between the wings was 5 feet, 5/8-inch (1.527 meters) and the lower wing was staggered 2 feet, 15/16-inch (0.633 meters) behind the upper wing. The wings’ incidence was +1°. Upper and lower wings were equipped with ailerons, and had no sweep or dihedral. The height of the Packard Lepère, sitting on its landing gear, was 9 feet, 7 inches (2.921 meters). The Packard Lepère had an empty weight of 2,561.5 pounds (1,161.9 kilograms) and its gross weight was 3,746.0 pounds (1,699.2 kilograms).
The fuselage was a wooden structure with a rectangular cross section. It was covered with three layers of veneer, (2 mahogany, 1 white wood) with a total thickness of 3/32-inch (2.38 millimeters). The fuselage had a maximum width of 2 feet, 10 inches (0.864 meters) and maximum depth of 4 feet, 0 inches (1.219 meters).
The wings were also of wooden construction, with two spruce spars and spruce ribs. Three layers of wood veneer covered the upper surfaces. Heavy bracing wires were used. These had an airfoil cross-section and actually provided additional lift. The interplane struts were unusual in that they were fully-framed units.
The Packard Lepère was powered by a water-cooled, normally-aspirated, 1,649.336-cubic-inch-displacement (27.028 liter) Liberty L-12 single overhead cam (SOHC) 45° V-12 engine with a compression ratio of 5.4:1. The Liberty produced 408 horsepower at 1,800 r.p.m. The L-12 as a right-hand tractor, direct-drive engine and it turned turned a two-bladed, fixed-pitch wooden propeller. The Liberty 12 was 5 feet, 7.375 inches (1.711 meters) long, 2 feet, 3.0 inches (0.686 meters) wide, and 3 feet, 5.5 inches (1.054 meters) high. It weighed 844 pounds (383 kilograms).
The engine coolant radiator was positioned horizontally in the center section of the Lepère’s upper wing. Water flowed through the radiator at a rate of 80 gallons (303 liters) per minute.
Packard Lepère L USA C.II S.C. 40015, McCook Field project number P53, left profile. The turbocharger’s turbine housing is mounted above the propeller driveshaft. (U.S. Air Force)
The Packard Lepère had a maximum speed of 130.4 miles per hour (209.9 kilometers per hour) at 5,000 feet (1,524 meters), 127.6 miles per hour (205.4 kilometers per hour) at 10,000 feet (3,048 meters), 122.4 miles per hour (197.0 kilometers per hour) at 15,000 feet (4,572 meters), 110.0 miles per hour (177.0 kilometers per hours) at 18,000 feet (5,486 meters) and 94.0 miles per hour (151.3 kilometers per hour) at 20,000 feet (6,096 meters). Its cruising speed was 112 miles per hour (180 was kilometers per hour). The airplane could climb to 5,000 feet in 4 minutes, 24 seconds, and to 20,000 feet in 36 minutes, 36 seconds. In standard configuration, the Packard Lepère had a service ceiling of 20,200 feet (6,157 meters). Its range was 320 miles (515 kilometers).
The fighter’s armament consisted of two fixed M1918 Marlin .30-caliber aircraft machine guns mounted on the right side of the fuselage, synchronized to fire forward through the propeller arc, with 1,000 rounds of ammunition, and two M1918 Lewis .30-caliber machine guns on a flexible mount with 970 rounds of ammunition.
The Air Service had ordered 3,525 of these airplanes, but when the War ended only 28 had been built. The contract was cancelled.
Six Packard Lepères were used for flight testing at McCook Field, Dayton, Ohio, assigned project numbers P 44, P 53, P 54, P 65, P 70 and P 80. One of these, flown by Major Rudolph W. Schroeder, set two Fédération Aéronautique Internationale (FAI) World Records for Altitude at 9,455 meters (31,020 feet), 18 September 1918.² On 6 September 1919, Schroeder flew a Packard Lepère to 8,616 meters (28,268 feet) while carrying a passenger. This set two more World Altitude Records.³ Flying P 53, A.S. 40015, he set a fifth FAI altitude record of 10,093 meters (33,114 feet), 27 February 1920.⁴ On 28 September 1921, Captain John A. Macready flew P 53 to an altitude of 40,800 feet (12,436 meters). On 13 October 1922, 1st Lieutenant Theodore J. Koenig flew P 53 to win the Liberty Engine Builders’ Trophy Race at Selfridge Field, near Mount Clemens, Michigan. Koenig completed ten laps of the triangular racecourse in 2:00:01.54, at an average speed of 128.8 miles per hour (207.3 kilometers per hour).
The only Packard Lepère in existence, serial number A.S. 42133, is in the collection of the National Museum of the United States Air Force, Wright-Patterson Air Force Base, Ohio.
Lieutenant John A Macready flew this turbosupercharged Packard Lepère L USA C.II, S.C 40015, McCook Field project number P53, to an altitude of 40,800 feet, 28 September 1921. (U.S. Air Force)Barograph chart showing Lieutenant Macready’s record altitude of 40,800 feet (12,192 meters), 28 September 1921. (Sally Macready Wallace via www.earlyaviators.com)
Wing Commander Walter Frame Gibb, D.S.O., D.F.C. (Photograph courtesy of Neil Corbett, Test & Research Pilots, Flight Test Engineers)
29 August 1955: Wing Commander Walter Frame Gibb, D.S.O., D.F.C., a test pilot for the Bristol Aeroplane Co., set a new Fédération Aéronautique Internationale (FAI) world record for altitude when he flew an English Electric Canberra B Mk.II, WD952, to 20,083 meters (65,889 feet), near Filton, Gloucestershire.¹
A brief notice in Flight:
At 3 p.m. last Monday, Bristol assistant chief test pilot Walter Gibb took off from Filton in the Olympus-Canberra in which, during May 1953, he established a world’s height record of 63,668 feet. The Canberra, which has since been fitted with two Olympus 102 BOI.11 turbojets, was airborne for one hour. Gibb’s purpose was to better his own record and, accordingly, G/C du Boulay and Mr. Philip Mayne, of the Royal Aero Club, were in attendance. Personnel of the R.A.E. were engaged in calibration, but as we go to press it was unlikely that the outcome would be known before the end of next week.
—FLIGHT and Aircraft Engineer, No. 2432, Vol. 68, Friday, 2 September 1955 at Page 338, Column 1
The Telegraph reported:
. . . taking off from Filton, he climbed over the Bristol Channel towards Ireland and levelled off at 50,000 ft in order to burn off fuel to lighten the aircraft before continuing his ascent.
He turned east and finally reached a new record altitude of 65,876 ff (nearly 12.5 miles high) over Bristol. Gibb, who was flying solo, observed: “The last 500 ft took an awfully long time. It was the most difficult flying I have ever experienced.”
WD952 was equipped with the new Bristol Olympus BOI.11 Mk.102 engines. The Olympus was a two-spool axial-flow turbojet which produced 12,000 pounds of thrust (53.38 kilonewtons).
Wing Commander Gibb’s record-setting Olympus-powered English Electric Canberra B Mk.II, WD952. (Photograph courtesy of Neil Corbett)
This was the second FAI altitude record set by Gibb with WD952. Two years earlier, 4 May 1953, Gibb had flown the Canberra to an altitude of 19,406 meters (63,668 feet).²
On 9 April 1956, WD952 was taking off from Filton when the left engine suffered a turbine blade failure at 50 feet (15 meters). In the resulting forced landing, the Canberra’s left wing struck an oak tree and was torn off. The record-setting airplane was damaged beyond repair and was scrapped.
The English Electric Canberra B.2 was the first production variant of a twin-engine, turbojet powered light bomber. The bomber was operated by a pilot, navigator and bombardier. It was designed to operate at very high altitudes. The Canberra B.2 was 65 feet, 6 inches (19.964 meters) long with a wingspan of 64 feet, 0 inches (19.507 meters) and height of 15 feet, 7 inches (4.750 meters). The wing used a symmetrical airfoil and had 2° angle of incidence. The inner wing had 2° dihedral, and the outer wing, 4° 21′. The total wing area was 960 square feet (89.2 square meters). The variable-incidence tail plane ad 10° dihedral. The airplane’s maximum takeoff weight was 46,000 pounds ( kilograms).
The Canberra B.2 was powered by two Rolls-Royce Avon RA.3 Mk. 101 engines. The RA.3 was a single-spool axial-flow turbojet with a 12-stage compressor section and single-stage turbine. It was rated at 6,500-pounds-thrust (28.91 kilonewtons).
The B.2 had a maximum speed of 450 knots (518 miles per hour/833 kilometers per hour). It was restricted to a maximum 0.75 Mach from Sea Level to 15,000 feet (4,572 meters), and 0.79 Mach from 15,000 to 25,000 feet (7.620 meters). Above that altitude the speed was not restricted, but pilots were warned that they could expect compressibility effects at 0.82 Mach or higher.
The Canberra was produced in bomber, intruder, photo reconnaissance, electronic countermeasures and trainer variants by English Electric, Handley Page, A.V. Roe, and Short Brothers and Harland. In the United States, a licensed version, the B-57A Canberra, was built by the Glenn L. Martin Company. The various versions were operated by nearly 20 nations. The Canberra was the United Kingdom’s only jet-powered bomber for four years. The last one in RAF service, a Canberra PR.9, made its final flight on 28 July 2008.
Joe Walker and the X-15 on Rogers Dry Lake at the end of a flight. Walker is wearing a David Clark Co. MC-2 full-pressure suit. (U.S. Air Force)
22 August 1963: On his twenty-fifth and last flight with the X-15 program, NASA Chief Research Test Pilot Joseph Albert Walker would attempt a flight to Maximum Altitude. Engineers had predicted that the X-15 was capable of reaching 400,000 feet (121,920 meters) but simulations had shown that a safe reentry from that altitude was risky. For this flight, Flight 91, the flight plan called for 360,000 feet (109,728 meters) to give Walker a safety margin. Experience had shown that slight variations in engine thrust and climb angle could cause large overshoots in peak altitude, so this was not considered an excessive safety margin.
For this flight, Joe Walker flew the Number 3 X-15, 56-6672. It was the only one of the three North American Aviation X-15s equipped with the Honeywell MH-96 flight control system, which had been developed to improve control of the rocketplane outside Earth’s atmosphere. This flight was the twenty-second for Number 3.
North American Aviation X-15A 56-6672 immediately after being dropped by the Boeing NB-52 Stratofortress. (NASA)
Walker and the X-15 were airdropped from the Boeing NB-52A Stratofortress 52-003, The High and Mighty One, at 45,000 feet (13,716 meters) above Smith Ranch Dry Lake, Nevada, about half-way between the city of Reno and the NASA High Range Tracking Station at Ely. Launch time was 10:05:57.0 a.m., PDT. Walker ignited the Reaction Motors XLR99-RM-1 rocket engine. This engine was rated at 57,000 pounds of thrust. Experience had shown that different engines varied from flight to flight and that atmospheric conditions were a factor. Thrust beyond 60,000 pounds was often seen, but this could not be predicted in advance. The flight plan called for the duration of burn to be 84.5 seconds on this flight. The X-15 climbed at a 45° angle.
As Walker was about to shut down the engine according to plan, it ran out of fuel. The total burn time was 85.8 seconds, just slightly longer than planned.
“At burnout, Joe was passing 176,000 feet [53,645 meters] and traveling at 5,600 feet per second[1,707 meters per second]. He then began the long coast to peak altitude. It would take almost 2 minutes to reach peak altitude after burn out. Two minutes does not seem like a lot of time, but try timing it. Just sit back in your easy chair and count off the seconds. It is almost impossible to believe that you can continue to coast up in altitude for that length of time after the engine burns out. It gives you some feel for how much energy is involved at those speeds. For comparison, when you throw a ball up in the air as hard as you can, it only coasts upward a maximum of 4 or 5 seconds. The X-15 coasted up for 120 seconds.
“The airplane would coast up another 178,000 feet [54,254 meters] during that time to peak out at 354,200 feet. . . .”[107,960 meters]
—At The Edge of Space: The X-15 Flight Program, by Milton O. Thompson, Smithsonian Institution Press, Washington, 1992, Chapter 5 at Page 125.
Joe Walker and the X-15 reached the peak of their ballistic trajectory at 354,200 feet (67.083 miles, 107,960 meters). Walker pitched the nose down to be in the proper attitude for atmospheric reentry. The X-15 decelerated as it hit the atmosphere and Walker experienced as much as 7 Gs. The rocketplane’s aerodynamic control surfaces again became operational as it descended through 95,000 feet (28,956 meters) and Walker leveled at 70,000 feet (21,336 meters). He then glided to a landing on Rogers Dry Lake at Edwards Air Force Base, California, after 11 minutes, 8.6 seconds of flight.
Flight 91 was the highest flight achieved by any of the X-15s. It was Joe Walker’s second flight into space. His record would stand for the next 41 years.
The Società Italiana Caproni, Milano Caproni Ca. 113 Alta Quota was developed from the Ca.113 trainer. It was powered by a British-built Bristol Pegasus, the same type used by the Houston Mount Everest Flying Expedition to fly over Mount Everest the previous week. It was an air-cooled, supercharged, 1,752.79-cubic-inch-displacement (28.72 liter) nine-cylinder radial engine, with a compression ratio of 5.3:1. It had a Normal Power rating of 525 horsepower at 2,000 r.p.m. at 11,000 feet (3,353 meters), and produced a maximum of 575 horsepower at 2,300 r.p.m. at 13,000 feet (3,962 meters). It drove a four-blade ground-adjustable metal propeller.
The Ca.113 was powered by an Alfa-Romeo engine developed from the license-built Bristol Pegasus. It had a Normal Power rating of 525 horsepower at 2,000 r.p.m. at 11,000 feet (3,353 meters), and produced a maximum of 575 horsepower at 2,300 r.p.m. at 13,000 feet (3,962 meters).
