[Llarry]

The first aerial refueling took place in June of 1923 when one U.S. Army Air Service DH-4B refueled another. Air refueling remained more or less a novelty for a number of years thereafter, although the Sir Alan Cobham worked out hose and drogue refueling in the 1930s in the UK and founded Flight Refueling Limited.

It was 1948 before military requirements -- the need to allow bombers to reach the USSR -- drove the development of operational aerial refueling. The first U.S. Air Force refueler was the KB-29M Superfortress which used hose refueling. But the USAF's Strategic Air Command wanted a better system for their nuclear weapon-carrying bombers.

Boeing came up with the flying boom refueling method around 1950. The initial application was in the KB-29P; 116 bombers were converted to tankers in 1950-51.

The fuel capacity of the KB-29 was insufficient for Air Force requirements and the USAF bought 811 Boeing KC-97 tankers beginning in 1951. When heavily loaded with fuel, the KC-97 had difficulty flying fast enough to refuel the newest jet bombers, and the KC-97 fleet was retrofitted with a pair of turbojets to boost speed when required.

The use of the KC-97s was jealously guarded by the Strategic Air Command for use by strategic bombers. The Tactical Air Command soon wanted an aerial refueling capability for its fighters and light bombers; the answer came in the conversion of Boeing B-50 bombers to KB-50 tankers using the hose and drogue method of refueling. The KB-50J and K models, like the KC-97L of SAC, added turbojets to boost speed when refueling high-performance jets.

What was really needed was a jet tanker, and that came in the form of the Boeing KC-135 Stratotanker, which I have previously discussed, and which was bought in large numbers and ultimately replaced all the obsolescent piston-powered earlier tankers.

https://en.wikipedia.org/wiki/Aerial_refueling

Photos:
1) June 1923 refueling
2) KB-29M refueling another B-29
3) KB-29M refueling B-50
4) KB-29P with boom
5) KC-97F refueling B-47B
6) KC-97L (note added jet engines)
7) KB-50 refueling two F-104s (note 3rd hose on centerline not used)
8) KC-135A refuels B-52D

[Llarry]

Having posted about the early refuelers and (earlier discussed) the Boeing KC-135 Stratotanker, let me address the future of Air Force aerial refueling.

The U.S. Air Force operates over 350 Boeing KC-135s; of this total, about 140 are active Air Force and 210 or so are Air Force Reserve Command and Air National Guard aircraft. The USAF is currently in the middle of buying 179 Boeing 767-based KC-46A tankers (first photo) to replace some of the nearly antique KC-135s; about 60 of the new ones are already in service. The last of the 179 should be delivered in 2029, which will still leave the tanker force with quite a few old KC-135s.

Last year the Air Force revised its future tanker scheme and now plans to buy about 75 additional KC-46As as a bridge to the future.

As currently envisioned, that future will include a future stealthy tanker to become operational in the 2030s.

The problem is that the USAF has become so dependent on aerial refueling that the potential shoot-down of a tanker would have the potential to cause the loss by fuel starvation of multiple fighters or bombers. There is a new generation of very long range (100-200 miles or more) air-to-air missiles that has generated this concern.

It's still too early to predict the form of any future tanker, but some concepts have been preliminarily explored. The traditional approach -- adaptation of a commercial aircraft -- is unlikely to meet the requirement. See the attached CGI photos for some possibilities.

[vreihen16]

Interesting story about Bazooka Charlie and his "Rosie the Rocketer" Piper L-4 Grasshopper.....



https://www.usatoday.com/story/news/...r/72087625007/


.

[Llarry]

A history of large American radial engines... the radial engine was invented in 1901 in primitive water-cooled form and the first air-cooled radial ran a few years later.

The first U.S. radial was the Lawrance J-1 of 1921, which was funded by the U.S. Navy. Shortly thereafter, the Navy encouraged the acquisition of Lawrance by Wright, which became an important producer of radials. Competitor Pratt & Whitney was founded in 1925; the competition between Wright and P&W would continue for many years.

The earliest large radial was the Wright R-1820 Cyclone 9-cylinder engine of 1931. The R-1820 was also among the last of the radials to be produced, with final deliveries taking place around 1967. Over 47,000 were built and R-1820s powered a large number of aircraft: Grumman's FF biplane fighter, Curtiss' SBC dive bomber in the early days, Boeing's B-17 bomber, some Douglas DC-3s and the Douglas SBD dive bomber and Eastern FM-2 Wildcat of World War II fame. After WWII, the R-1820 powered the Grumman S-2 carrier ASW aircraft and HU-16 Albatross amphibian as well as Piasecki H-21 and Sikorsky H-34 helicopters. The R-1820 was the largest successful single-row radial engine.

The Pratt & Whitney R-1830 Twin Wasp of 1932 was a competitor to the R-1820. It was a two-row 14-cylinder engine and was the most-produced American radial engine of all time, with over 173,000 delivered. It powered the Consolidated PBY Catalina flying boat, the Douglas DC-3 and military C-47/Dakota, the Consolidated B-24 Liberator bomber. The R-1830 ended production in 1951, well before the R-1820.

Pratt & Whitney enlarged the R-1830's bore to make the R-2000, which powered the Douglas C-54 and DC-4 and later the DHC Caribou. Around 13,000 of these engines were built from 1942 to 1968.

Aircraft designers demanded ever more power and radials continued to grow in size. Power also increased due to the use of higher-octane fuels developed during World War II.

The Wright R-2600 Twin Cyclone two-row 14-cylinder radial was introduced in 1935 and powered a number of World War II combat aircraft, such as the Douglas A-20 attack plane, the North American B-25 bomber, the Navy's PBM flying boat and the Grumman-designed TBF/TBM Avenger torpedo plane and Curtiss SB2C dive bomber. Although over 85,000 were built, the R-2600 did not stay in production long after the war's end.

Pratt & Whitney planned a two-row 18-cylinder engine of about 2,600 cubic inches but when they learned of Wright's R-2600, enlarged the engine to 2,800 cubic inches. The P&W R-2800 Double Wasp was introduced in 1937. It powered a number of important World War II combat aircraft such as the Martin B-26 medium bomber, the Republic P-47 Thunderbolt fighter, the Northrop P-61 Black Widow night fighter and the Navy/Marine Vought F4U Corsair and F6F Hellcat carrier fighters. It also powered the Lockheed PV patrol plane and late in the war the Douglas A-26 Invader attack plane. Postwar, it powered the Fairchild C-123 transport and the Douglas DC-6 airliner. It was also used in pairs to power the first U.S. heavy-lift Sikorsky H-37 helicopter. Later it was used to power the Canadair CL-215 firefighting aircraft. Over 125,000 R-2800s were built before production ceased in 1960.

Wright enlarged their 14-cylinder R-2600 to 18 cylinders to produce the R-3350 Duplex-Cyclone in 1937. The R-3350 became a very high priority as it was planned to power the Boeing B-29 Superfortress heavy bomber. Unfortunately, development was troubled; it took several years to sort out the difficulties. During WWII, all R-3350 production was reserved for the B-29. After the war, it was used to power the Douglas AD (A-1) Skyraider, the Lockheed P2V (P-2) Neptune land-based patrol plane, the last of the Navy flying boats, the Martin P5M (P-5) Marlin as well as several larger aircraft: The Lockheed Super Constellation (C-121), the Douglas DC-7 airliner and the Fairchild C-119 Flying Boxcar. Production ended in the 1950s and totaled over 29,000 or over 50,000, depending on the source.

Pratt & Whitney's final radial was the monster R-4360 Wasp Major, which was first run in 1944. It was intended to power the Consolidated (Convair) B-36 six-engine very heavy long-range bomber, which did not fly until well after war's end. The R-4360 was a four-row radial with 7 cylinders per row for a total of 28 (and 56 spark plugs per engine!) The R-4360 had a troubled career; the only civilian application was the Boeing 377 Stratoliner but the airlines that bought the 377 found it to be troublesome due to engine maintenance requirements and high fuel consumption. The 377's career was not long. Boeing also used the R-4360 in the related KC-97 tanker and the B-50 heavy bomber (a B-29 on steroids). The Fairchild C-119 Flying Boxcar used the R-4360 at first, but later models switched to the slightly less powerful but more reliable Wright R-3350. Almost 19,000 R-4360s were built by 1955, when production ceased.

A note on aviation gasoline: The ultimate piston-engine fuel was 115/145 avgas, which attained its very high octane equivalency through use of lead supplements. The engines running today in collector aircraft engines do not develop the high power (or performance) of those in the heyday of piston engines due to lower quality fuel.

https://en.wikipedia.org/wiki/Radial_engine

[Lady Jane]

Posted for Llarry regarding radial engines.

EDIT: Found a smaller Gif.

[Llarry]

Here's another illustration of the workings of a radial engine. This one is a 9-cylinder.

[Lady Jane]

Hughes XF-11

https://www.warhistoryonline.com/air...hes-xf-11.html

Single four bladed prop and dual contra-rotating props prototypes.

Powered by two Pratt & Whitney R-4360-31 Wasp Major 28-cylinder, air-cooled radial piston engines producing a total of 6000hp.

[Lady Jane]

The sleek Republic XF-12 Rainbow

https://en.wikipedia.org/wiki/Republic_XF-12_Rainbow

[Llarry]

The first fighter aircraft came into being in 1915 during World War I. Initially -- in 1914 -- airplanes were considered to be valuable as observation aircraft for the ground war. As the war progressed, opposing two-seat observation aircraft took shots at each other.

The initial firing of a machine gun in front of the pilot was by French pilot Roland Garros, who fitted metal plates to the wooden propellor of his aircraft to avoid destroying the prop when the gun fired. In April of 1915, Garros had engine trouble and was forced to land behind German lines. German troops captured plane and pilot and discovered the arrangement.

Anthony Fokker was a Dutch aviation pioneer who had moved to Germany and started supplying aircraft to the German army in 1913. He was tasked with devising a better system than Garros' and quickly came up with a synchronizer system that would interrupt gunfire when the propellor was in the way. The German army ordered 30 Fokker monoplanes (eindeckers) equipped with a single synchronized 7.92mm machine gun each.

The first aerial victory came on July 1, 1915, when a German pilot shot down an enemy aircraft in the Flanders area. The air war was on.

Initially, a single Fokker E.I fighter was assigned to each unit of 6 observation two-seaters; there were no fighter squadrons. The E.I was powered by an 80 horsepower 7-cylinder rotary engine; just 54 were built before it was superseded by the improved E.II, which had a 100 hp engine and a slightly reduced wingspan. Only 49 E.IIs were built, as the fighters were still assigned in small numbers to observation units.

Production picked up with the E.III model, which had greater fuel capacity and other changes. Some E.IIIs were fitted with twin machine guns, but the standard fit was still a single gun. The E.III first saw action in December of 1915; 250-300 airplanes were built in 1915-1916 and they were flown by both the army and the navy.

By this time, the Allies had reacted to the losses with fighters of their own. In January of 1916, the French Nieuport 11 became operational; it was a biplane with a single machine gun mounted on top of the upper wing as the Allies did not have synchronizers yet. Several hundred Nieuport 11s were built in 1916.

The British also fielded a fighter in February of 1916. The Airco DH.2 designed by de Havilland was a pusher, which eliminated the need for synchronization. 453 DH-2s were built.

The Allied response blunted the impact of the German Eindeckers but German aircraft innovation was not idle. In April 1916 the first of the Albatros fighters flew. The Albatros D.I was fast and powerful and was armed from the start with twin 7.92mm machine guns. It was powered by a water-cooled Mercedes D.III inline six cylinder engine of 160 hp. Only 50 D.Is were built before being replaced by the Albatros D.II; production picked up with some 275 or more D.IIs delivered.

The aero technology battle continued late in 1916 with the introduction of new fighters by both the French and the British. By now they used synchronizers, too.

The French SPAD VII was introduced in late 1916. Like the Albatros it was powerful and fast, though still mounting just one .303 machine gun. It was powered by a Hispano-Suiza water-cooled V-8 of 140 hp -- late versions had even more power. Some 6,000 SPAD VIIs were built -- the fighter effort was becoming a big deal!

The British introduced the Sopwith Pup slightly later than the SPAD. The Pup used a Le Rhone 9C rotary engine of 80 hp and, like the SPAD, retained just one .303 machine gun. Just under 1,800 Pups were produced.

In December of 1916 the latest Albatros D.III entered combat. As 1917 began, the German fighters were dominant once again, though the balance was not as lopsided as the early 1915 era. The D.III continued with a Mercedes 160 hp six. 1,866 were built. (no photo)

Britain introduced a Sopwith Triplane fighter in the spring of 1917. The Triplane used a Clerget 9BG rotary engine of 130 hp and was still armed with a single .303 machine gun. While only 147 were built, it was significant in that it prompted the adoption of the triplane by Fokker Aircraft later in 1917. (see below)

The late spring and summer of 1917 saw rapid developments. The British SE5 biplane fighter saw combat in April. 60 SE5s were quickly followed by 5,145 SE5a fighters with 200 hp Hispano-Suiza water-cooled V-8s. The SE5s had one machine gun in front of the pilot and another on top of the upper wing.

In May 1917 the improved Albatros D.V entered combat; about 2,500 were built and these stayed operational until the end of the war in late 1918.

New fighters were coming fast and thick: In June the Sopwith F.1 Camel entered combat. It was equipped with twin .303s and powered by several different rotary engines of 130-150 hp. As with previous British fighters, some were flown by the Royal Navy Air Service. 5,490 were produced.

In August 1917 the SPAD XIII became operational. This model continued to use the French Hispano-Suiza water-cooled V-8 of 200 hp (220 hp in some later models) but the propellor was geared and it was armed with a pair of .303 machine guns. 8,472 were built. Between the British and the French, the Allied Powers were outproducing the Central Powers in fighters.

Shortly thereafter, in the autumn of 1917, the Germans introduced the Fokker Dr.I triplane fighter. The Dr.I reverted to rotary engine power with 110 hp and was exceptionally maneuverable, though tricky to fly. Armed with twin 7.92s, just 320 were delivered.

The final fighter to join the fight was the Fokker D.VII biplane, which became operational in May 1918. The D.VIII was powered by a Mercedes D.III inline water-cooled six of 160-170 hp. Some models substituted an engine from a new company called BMW: The BMW IIIa had 180 hp and with special fuel under emergency conditions could offer 235 hp. While the D.VII was outnumbered by Allied fighters, it was clearly the best fighter of the war. Post-WWI, the D.VIIs were taken over by the Allies and served in a number of air forces for some years.

[Llarry]

Tomcat Thursday

[Llarry]

And Tornado Thursday as well. Nice livery!

[Nairb1]

A great place to see WW1 planes flying.
Not the fanciest museum around but...

https://oldrhinebeck.org/

Air shows every weekend during the summer

[Llarry]

The Lockheed U-2 has always fascinated me. It began life in the early 1950s as a concept for a very high-altitude aircraft to sneak a peek behind the Communist Iron Curtain. The concept was close to a powered glider, with very low weight and a fragile structure. Power was provided by a then-new Pratt & Whitney J57 engine modified for high-altitude operation. The early U-2s did not include a (heavy) ejection seat for the pilot. The primary concern was the provision of an advanced camera system in a relatively large compartment behind the pilot called the Q-bay. The cameras were as advanced as the aircraft.

The U-2 began life as a Central Intelligence Agency project. Pilots were recruited from the Air Force and were "sheep-dipped" to disguise their USAF status. After a tour of duty with the U-2 -- during which they were paid by the CIA -- they would return to the Air Force with no loss of seniority.

Development was kept secret. A special division, called the "Skunk Works" within Lockheed was responsible for the project; the rest of the company was kept in the dark. The decision was made that testing would need to be accomplished at a secure remote facility and Lockheed selected Groom Lake, Nevada, to have a new airfield constructed for the tests.

By July of 1955, the first aircraft was ready, as was Groom Lake (referred to as "The Ranch.") The airplane was disassembled and flown to the site in a transport, then reassembled. Lockheed was responsible for the initial test program.

Early taxi tests showed the aircraft to be a handful for even a skilled pilot. To save weight, the aircraft had retractable dual-wheel main landing gear and a small tailwheel -- both on the centerline. In an era when tailwheel aircraft were fast disappearing, the aircraft was a "tail dragger" requiring a different technique to taxi, takeoff and land.

For taxiing and takeoff, the long wings could be fitted with small outrigger wheels called pogos. Once airborne, the pogos would be jettisoned for reuse. Upon landing, as the aircraft slowed it would fall off onto one wing or the other and the wingtips featured small skids to prevent wing damage. After the airplane came to a halt, ground crews would fit the pogos for the final taxi portion.

With light weight and a lot of wing area, the aircraft did not want to land. The technique was to put the tailwheel down first and then stall the aircraft to get it solidly on the ground.

After taxi tests and an inadvertent short hop on July 31st of 1955, the first flight was made on August 1st of 1955.

The "Angel" as the CIA called it, still did not have a designation, but soon was dubbed the U-2. U for utility -- yeah, right.

The number of U-2s to be built was small and there was no production line per se; I believe in the end 53 of these early U-2s were built.

By April of 1956, the U-2 and its pilots were ready. Two U-2As were flown as cargo to RAF Lakenheath in the UK to prepare for operational missions. As cover, the small unit was designated Weather Reconnaissance Squadron (Provisional) 1 and moved from the UK to Wiesbaden, West Germany, for the first overflights of the Soviet Union.

The first overflight -- with direct approval from President Eisenhower -- took place on July 4, 1956 and covered the Moscow and Leningrad areas. The mission was considered a great success, and the resulting photos were exceptional. Additional missions were approved.

In August of 1956, the second unit, WRS(P)-2, was established at Incirlik AB, Turkey. Shortly thereafter, the two squadrons were merged at Incirlik. Thirty missions were flown over the USSR from 1956 to 1960. While some had predicted that the U-2 would not be detected by the Soviets, it clearly was and many attempts were made to intercept the aircraft -- all unsuccessful. The Soviet interceptors simply could not reach the U-2's altitude.

In 1958 another unit was established at the Naval Air Station Atsugi, Japan, to overfly Asian targets.

Lockheed had further developed the U-2. The J57-powered U-2A was modified with a more powerful J75 engine and structurally strengthened. An ejection seat was provided for the pilot. The updated model was designated U-2B. Shortly thereafter, the U-2B's J75 was upgraded and the jet intakes were enlarged for better airflow, resulting in the U-2C. Earlier models were updated to the new configuration.

In 1957, the Air Force got their own U-2s with a unit at Laughlin AFB, Texas. In addition to photographic reconnaissance, they used their aircraft for weather recon and high-altitude air sampling related to atmospheric nuclear tests.

In 1960 the overflights of the Soviet Union came to a screeching halt when the USSR finally managed to down an Agency U-2B on May 1st of 1960. The fighters were still unsuccessful, but the U-2 was brought down by a barrage of SA-2 surface-to-air missiles which damaged the fragile plane and brought it down in pieces. The pilot lived and was taken prisoner. The Soviets recovered the wreckage of the aircraft and cameras. The overflights of the Soviet Union ceased, never to resume.

The CIA did continue to sponsor overflights of China by Nationalist Chinese pilots flying CIA-owned U-2C aircraft from Taiwan beginning in 1960. The rationale for this effort was the PRC effort to develop nuclear weapons and the targets were in Western China. The PRC, however, had also gotten SA-2 missiles and downed a number of flights despite efforts to skirt known SAM sites.

To shift gears a bit, the 1962 Cuban missile crisis featured USAF overflights of Cuba in an effort to gain intelligence on the Soviet buildup in Cuba; it was an Air Force U-2 that first detected the presence of nuclear-armed ballistic missiles in October of 1962. Later in October, a USAF U-2 was shot down by a SA-2 SAM over Cuba and the pilot was killed.

Late in the career of the early U-2s, it was finally recognized that a dual-cockpit trainer version would be invaluable in reducing the accident rate and a second cockpit was added where the Q-bay mission equipment would normally be.

By the mid-1960s, shootdowns and flying accidents had greatly reduced the inventory of available U-2s. It appeared that the tenure of this valuable intelligence asset was coming to an end. To avoid the resulting intel shortfall, the CIA and USAF contracted with Lockheed to buy 12 more aircraft -- 6 CIA and 6 Air Force. To correct some of the deficiencies with the original design, Lockheed undertook a substantial redesign which was designated the U-2R. The fuselage was stretched by 13 feet and the wing was considerably bigger. There were a host of other changes that transformed the U-2. The U-2R flew in August 1967. I will defer discussion of the new, improved U-2R to another post.

Early U-2s were also provided to NASA for use in earth science missions. NASA paints their U-2s high-visibility white.

While I do not know when the last first-generation U-2 was finally retired, I suspect it was in the early 1980s.

Edit: I neglected to add a couple of interesting facts about the U-2:
-- The U-2C's J75 engine developed 17,000 lbs of thrust for takeoff; at altitude, the air is so thin that the engine is only putting out about 500 lbs of thrust. Of course, at 70,000+ feet of altitude, the drag is very little.
-- Skill in piloting the U-2 is not limited only to takeoffs and landings. At altitude, the U-2 -- particularly the early models -- is operating very close to the "coffin corner." Any slower and the aircraft stalls; any faster and Mach buffeting is encountered. In either case, the fragile U-2 is susceptible to shedding its wings. The margin is only a few knots, so the pilot must be quite precise in maintaining the proper speed.

https://en.wikipedia.org/wiki/Lockheed_U-2

[flybigjet]

Originally Posted by Llarry

The Lockheed U-2 has always fascinated me. It began life in the early 1950s as a concept for a very high-altitude aircraft to sneak a peek behind the Communist Iron Curtain. The concept was close to a powered glider, with very low weight and a fragile structure. Power was provided by a then-new Pratt & Whitney J57 engine modified for high-altitude operation. The early U-2s did not include a (heavy) ejection seat for the pilot. The primary concern was the provision of an advanced camera system in a relatively large compartment behind the pilot called the Q-bay. The cameras were as advanced as the aircraft.

The U-2 began life as a Central Intelligence Agency project. Pilots were recruited from the Air Force and were "sheep-dipped" to disguise their USAF status. After a tour of duty with the U-2 -- during which they were paid by the CIA -- they would return to the Air Force with no loss of seniority.

Development was kept secret. A special division, called the "Skunk Works" within Lockheed was responsible for the project; the rest of the company was kept in the dark. The decision was made that testing would need to be accomplished at a secure remote facility and Lockheed selected Groom Lake, Nevada, to have a new airfield constructed for the tests.

By July of 1955, the first aircraft was ready, as was Groom Lake (referred to as "The Ranch.") The airplane was disassembled and flown to the site in a transport, then reassembled. Lockheed was responsible for the initial test program.

Early taxi tests showed the aircraft to be a handful for even a skilled pilot. To save weight, the aircraft had retractable dual-wheel main landing gear and a small tailwheel -- both on the centerline. In an era when tailwheel aircraft were fast disappearing, the aircraft was a "tail dragger" requiring a different technique to taxi, takeoff and land.

For taxiing and takeoff, the long wings could be fitted with small outrigger wheels called pogos. Once airborne, the pogos would be jettisoned for reuse. Upon landing, as the aircraft slowed it would fall off onto one wing or the other and the wingtips featured small skids to prevent wing damage. After the airplane came to a halt, ground crews would fit the pogos for the final taxi portion.

With light weight and a lot of wing area, the aircraft did not want to land. The technique was to put the tailwheel down first and then stall the aircraft to get it solidly on the ground.

After taxi tests and an inadvertent short hop on July 31st of 1955, the first flight was made on August 1st of 1955.

The "Angel" as the CIA called it, still did not have a designation, but soon was dubbed the U-2. U for utility -- yeah, right.

The number of U-2s to be built was small and there was no production line per se; I believe in the end 53 of these early U-2s were built.

By April of 1956, the U-2 and its pilots were ready. Two U-2As were flown as cargo to RAF Lakenheath in the UK to prepare for operational missions. As cover, the small unit was designated Weather Reconnaissance Squadron (Provisional) 1 and moved from the UK to Wiesbaden, West Germany, for the first overflights of the Soviet Union.

The first overflight -- with direct approval from President Eisenhower -- took place on July 4, 1956 and covered the Moscow and Leningrad areas. The mission was considered a great success, and the resulting photos were exceptional. Additional missions were approved.

In August of 1956, the second unit, WRS(P)-2, was established at Incirlik AB, Turkey. Shortly thereafter, the two squadrons were merged at Incirlik. Thirty missions were flown over the USSR from 1956 to 1960. While some had predicted that the U-2 would not be detected by the Soviets, it clearly was and many attempts were made to intercept the aircraft -- all unsuccessful. The Soviet interceptors simply could not reach the U-2's altitude.

In 1958 another unit was established at the Naval Air Station Atsugi, Japan, to overfly Asian targets.

Lockheed had further developed the U-2. The J57-powered U-2A was modified with a more powerful J75 engine and structurally strengthened. An ejection seat was provided for the pilot. The updated model was designated U-2B. Shortly thereafter, the U-2B's J75 was upgraded and the jet intakes were enlarged for better airflow, resulting in the U-2C. Earlier models were updated to the new configuration.

In 1957, the Air Force got their own U-2s with a unit at Laughlin AFB, Texas. In addition to photographic reconnaissance, they used their aircraft for weather recon and high-altitude air sampling related to atmospheric nuclear tests.

In 1960 the overflights of the Soviet Union came to a screeching halt when the USSR finally managed to down an Agency U-2B on May 1st of 1960. The fighters were still unsuccessful, but the U-2 was brought down by a barrage of SA-2 surface-to-air missiles which damaged the fragile plane and brought it down in pieces. The pilot lived and was taken prisoner. The Soviets recovered the wreckage of the aircraft and cameras. The overflights of the Soviet Union ceased, never to resume.

The CIA did continue to sponsor overflights of China by Nationalist Chinese pilots flying CIA-owned U-2C aircraft from Taiwan beginning in 1960. The rationale for this effort was the PRC effort to develop nuclear weapons and the targets were in Western China. The PRC, however, had also gotten SA-2 missiles and downed a number of flights despite efforts to skirt known SAM sites.

To shift gears a bit, the 1962 Cuban missile crisis featured USAF overflights of Cuba in an effort to gain intelligence on the Soviet buildup in Cuba; it was an Air Force U-2 that first detected the presence of nuclear-armed ballistic missiles in October of 1962. Later in October, a USAF U-2 was shot down by a SA-2 SAM over Cuba and killed.

Late in the career of the early U-2s, it was finally recognized that a dual-cockpit trainer version would be invaluable in reducing the accident rate and a second cockpit was added where the Q-bay mission equipment would normally be.

By the mid-1960s, shootdowns and flying accidents had greatly reduced the inventory of available U-2s. It appeared that the tenure of this valuable intelligence asset was coming to an end. To avoid the resulting intel shortfall, the CIA and USAF contracted with Lockheed to buy 12 more aircraft -- 6 CIA and 6 Air Force. To correct some of the deficiencies with the original design, Lockheed undertook a substantial redesign which was designated the U-2R. The fuselage was stretched by 13 feet and the wing was considerably bigger. There were a host of other changes that transformed the U-2. The U-2R flew in August 1967. I will defer discussion of the new, improved U-2R to another post.

Early U-2s were also provided to NASA for use in earth science missions. NASA paints their U-2s high-visibility white.

While I do not know when the last first-generation U-2 was finally retired, I suspect it was in the early 1980s.

Edit: I neglected to add a couple of interesting facts about the U-2:
-- The U-2C's J75 engine developed 17,000 lbs of thrust for takeoff; at altitude, the air is so thin that the engine is only putting out about 500 lbs of thrust. Of course, at 70,000+ feet of altitude, the drag is very little.
-- Skill in piloting the U-2 is not limited only to takeoffs and landings. At altitude, the U-2 -- particularly the early models -- is operating very close to the "coffin corner." Any slower and the aircraft stalls; any faster and Mach buffeting is encountered. In either case, the fragile U-2 is susceptible to shedding its wings. The margin is only a few knots, so the pilot must be quite precise in maintaining the proper speed.

https://en.wikipedia.org/wiki/Lockheed_U-2

Here's an interesting Smithsonian article that adds a bit more color--

https://www.smithsonianmag.com/air-s...deuce-7405385/

A little trivia: The U-2 was one of the only aircraft (that I know of) that required an actual flight by the prospective pilot during their interview. If you were selected to "potentially" fly the U-2 (based somewhat near Sacramento, CA at Beale AFB), you came out, did a face-to-face interview and then went up in a two-seat model to see if you could figure out the landing. Due to it's stupidly large wing-- the U-2 just does. not. want. to. land.

In fact, it's such a tough aircraft to land that you have another pilot in a chase car (usually a Mustang or a Camaro iirc) that goes bombing down the runway behind you talking you down and telling you how much distance you had between the main gear and the ground-- it's actually a special qual and the pilots who do it have to take check rides.

The "coffin corner" that the article references is about 3-5 knots, iirc-- at least that's what a buddy of mine who flew them said. The jet can be a handful to fly.

R.

[BMWGUYinCO]

I think the U2 is still in service on some capacity today, right?

In fact I think it was a U2 that was flown up to photograph that Chinese spy balloon just recently....?

[Lady Jane]

Originally Posted by BMWGUYinCO

I think the U2 is still in service on some capacity today, right?

In fact I think it was a U2 that was flown up to photograph that Chinese spy balloon just recently....?

You would be correct.

https://www.popularmechanics.com/mil...e-spy-balloon/

[Llarry]

To continue with the U-2 story, as I've already mentioned, the CIA and the Air Force decided to each buy six more U-2s to augment the dwindling numbers of original U-2Cs and in 1967-68, the Lockheed Skunk Works produced those 12 U-2R aircraft to operate alongside the older aircraft.

There were a host of improvements incorporated in the U-2R. The extra wing gave the R a little more leeway at the coffin corner and the larger airframe provided more fuel and longer endurance. The time-tested J75-P-13B of the older smaller models was judged perfectly satisfactory and was retained. Space could now be found for some radar warning receivers as it was clear that the U-2 was not invulnerable. The high altitude gave cameras extra reach so that in some cases, the airplane need not directly overfly the target of interest.

The CIA used their contingent of U-2Rs to revitalize the Nationalist Chinese U-2 program. This time there were no shootdowns as the Agency planned flights smarter, avoiding air defenses and using the U-2R's altitude capability to conduct photo missions at standoff ranges. By the mid-1970s, the CIA aircraft were turned over to the Air Force.

The U-2R also brought an emphasis on signals intelligence, with equipment carried in pods on the wings. At altitude, difficult-to-intercept signals could be detected and monitored at great range. Many of these operations used a remoting concept whereby a secure digital data link allowed multiple operators on the ground to control and monitor radios in the U-2R pods. These operations required the U-2R to operate within signal range of the ground facility.

There the program would have been finished, but in the late 1970s, the Air Force wanted a sensor system to monitor Soviet and Warsaw Pact forces in Europe. In 1981 Lockheed re-started production of the U-2 as the TR-1 (T for Tactical, R for Recon) with the intent of stationing a number of TR-1A aircraft in Europe. The TR-1A had two relevant systems:
-- Advanced synthetic aperture radar system (ASARS) in an elongated nose. ASARS provides high-definition radar imagery at standoff distances.
-- Precision emitter location strike system (PLSS) pod on the wings. With multiple TR-1As operating in concert, PLSS can provide accurate location data on hostile emitters. To balance the TR-1A, pods were fitted to both wings.

Lockheed got contracts for 25 TR-1As and two dual-cockpit TR-1Bs which were delivered in 1983-1989. Quietly mixed among these were eight additional U-2Rs and a dual-seat U-2R(T) for training. NASA got in on the action as well and got two ER-2s (ER = Earth Resources). When the last of the 37 new-build aircraft was delivered in 1989, the early U-2s could finally be retired, as the fleet now numbered 49 of the larger U-2R and versions.

The TR-1As were stationed in a large squadron, the 95th Tactical Recon Squadron at RAF Alconbury in the UK. The squadron operated 18 TR-1As. As with so many of the late Cold War systems, the TR-1A matured just as the need for it went away with the end of the Cold War.

Ultimately, all the TR-1s were redesignated U-2R and U-2R(T). Aircraft accidents took their toll over the years and the fleet of U-2Rs was reduced.

The reliance on a data tether to a ground station proved awkward in some remote areas and in a program called Senior Span, the U-2R was given satellite data link capability; the antenna was contained in a distinctive aerodynamic fairing on the dorsal area of the aircraft.

In the 1990s, it became clear that the Pratt & Whitney J75 engines were becoming antiques -- the F-105 and F-106 that used the J75 were long retired -- and a new engine was needed. The GE F118 turbofan used in the still-secret B-2 bomber was perfect; it had increased thrust, better fuel consumption, weighed less and was a perfect fit in the U-2R airframe. The result was that all the aircraft were converted to F118-GE-101 power during the 1994-1998 period. The reduced weight and increased power also translated into a higher ceiling by several thousand feet for the resulting U-2S. Some airframe components were converted from aluminum to composites around the same time.

The U-2S continued to use film cameras on some missions but introduced digital imagery as well. Systems were improved on a continual basis and military commanders remained enthusiastic about the U-2's capabilities.

U-2 operations had been centralized under the 9th Reconnaissance Wing at Beale AFB near Sacramento, California. There are permanent and temporary operating locations elsewhere, such as Korea and the Middle East. The Senior Span system allowed the U-2 to operate virtually anywhere in the world and forward real-time imagery or SIGINT to anywhere else in the world.

In 2000, the U-2S started testing a "glass cockpit" replacing the old round gauges with modern multifunction digital displays. Soon the whole fleet was converted.

I've not yet mentioned the U-2 pilots. They are a special breed, spending long hours in a cockpit in a full pressure suit in case of depressurization. As flybigjet has related, there is a rigorous screening process to select the pilots and a lengthy training course before a new pilot flies an operational mission. Pilots undergo a rigorous regimen to prepare for each flight, including pre-breathing 100% oxygen to eliminate nitrogen from the blood.

Every few years someone proposes the retirement of the U-2 and is met with vociferous resistance by the users of the U-2 products. In fact, I believe that the retirement of the U-2S has been proposed quite recently. Given the daunting physiological challenges, Lockheed has proposed converting the U-2 to an unmanned platform over the years.

The current active aircraft include the two NASAS ER-2s, 27 U-2S single-seaters and 4 TU-2S trainers, meaning that 16 aircraft have been lost in accidents since 1968. Lockheed maintains that the U-2 fleet has plenty of airframe service life left.

https://en.wikipedia.org/wiki/Lockheed_U-2

[Llarry]

One minor addendum to the U-2 story...

On several occasions, both the early U-2s and the later U-2R were operated from Navy aircraft carriers. Doing so is awkward as the carriers' flight decks are normally crowded with parked Navy aircraft and the hangar deck below will not accommodate all the assigned aircraft. But it was done.

The early U-2C was modified with a tailhook and strengthened landing gear (and thus became a U-2G) for the first set of trials, which took place aboard USS Kitty Hawk in August 1963. The trials demonstrated that U-2 operations were feasible if the deck were cleared. (By the way: "Office of Naval Research? Yeah, right... wanna buy a bridge? )

The larger U-2R also conducted carrier operations in 1969; in the case of the U-2R and later U-2S, minimal modifications -- the addition of a tailhook -- were required.

The U-2G was only used once operationally; in May 1964 a U-2G flew from the USS Ranger to monitor French nuclear testing in the South Pacific.

The present U-2S retains the ability, but to my knowledge does not exercise it. A casual look at the typical carrier deck illustrates why not.

[Lady Jane]

Originally Posted by Llarry

On several occasions, both the early U-2s and the later U-2R were operated from Navy aircraft carriers.

If it was super difficult to land on a runway with the assistance of a chase car, it must have been sphincter puckering to land on a carrier.

[M-technik-3]

Originally Posted by Lady Jane

If it was super difficult to land on a runway with the assistance of a chase car, it must have been sphincter puckering to land on a carrier.

And if it was rough seas the up/down movement of the deck must be a nightmare.

[Llarry]

Originally Posted by Lady Jane

If it was super difficult to land on a runway with the assistance of a chase car, it must have been sphincter puckering to land on a carrier.

The photo of the U-2R catching an arresting wire gives me nightmares. That's called an "inflight engagement" and results in the aircraft slamming down on the deck once the wire plays out -- very hard on the landing gear. I wonder what the next photo in the series look like -- maybe a U-2 with flat tires or worse?

I would think the ideal carrier landing for a U-2 would be that the tailwheel touches the deck just as the hook engages the wire.

[Llarry]

A good photo of the MiG-15 of Korean War vintage. This one is owned by the Planes of Fame museum in Chino, California.

The highest-scoring fighter pilot of the Korean War, a Soviet pilot, flew the MiG-15 and tangled with American and United Nations aircraft during 1950-53.

The MiG-15 used a license-built version of a Rolls-Royce jet engine. (Thanks a lot, Limeys! )