Republic F-105 Thunderchief flyover, 419th TFW, Hill AFB, 4 June 1983. (U.S. Air Force)
4 June 1983: At Hill Air Force Base, Utah, the 419th Tactical Fighter Wing, the last U.S. Air Force unit flying the Republic F-105 Thunderchief supersonic fighter bomber, flew a Diamond of Diamonds 24-ship formation as the “Thud” was was withdrawn from service after 25 years to be replaced by the General Dynamics F-16.
Of 833 Thunderchiefs built by Republic Aviation Corporation, 334 were lost to enemy action during the Vietnam War. Though designed for air-to-ground attack missions, F-105s are officially credited with 27.5 victories in air combat.
Ten Republic F-105 Thunderchiefs (eight F-105Ds and two, two-place F-105Fs) of the U.S. Air Force Reserve 465th Tactical Fighter Squadron, 507th Tactical Fighter Group (later 301st TFW), on the flight line at Tinker Air Force Base, Oklahoma (USA), on 1 June 1978. (Camera Operator: Rick Diaz – U.S. Defense Visual Information Center photo DF-ST-86-12883)
Republic XP-47B 40-3051 prototype in flight. (Republic Aircraft Corporation)
6 May 1941: Just eight months after a prototype for a new single-engine fighter was ordered by the U.S. Army Air Forces, test pilot Lowery Lawson Brabham took off from the Republic Aviation Corporation factory airfield at Farmingdale, New York, and flew the prototype XP-47B Thunderbolt, serial number 40-3051, to Mitchel Field, New York.
During the flight, oil which had collected in the exhaust duct began burning. There was so much smoke that Brabham considered bailing out. He stayed with the prototype, though, and when he arrived at Mitchel Field, he exclaimed, “I think we’ve hit the jackpot!”
Alexander Kartveli
The prototype was designed by Alexander Kartveli, a Georgian immigrant and former chief engineer for the Seversky Aircraft Corporation, which became the Republic Aviation Corporation in 1939.
Alexander Kartveli (née Kartvelishvili, ალექსანდრე ქართველი) was born in Tbilisi, in the Kutais Governorate of the Russian Empire, (what is now, Georgia). After World War I, during which he was wounded, Kartvelishvili was sent to study at the Paris Aviation Higher College of Engineering in France by the government of the Democratic Republic of Georgia. He graduated in 1922. Kartvelishvili did not return to his country, which had fallen to the Red Army in the Soviet-Georgian War. He worked for Blériot Aéronautique S.A. until 1928, when he was employed by the Fokker American Company (also known as Atlantic Aircraft, or Atlantic-Fokker) which was headquartered at Passaic, New Jersey, in the United States. In 1931, he became chief engineer for the Seversky Aircraft Company in Farmingdale.
Republic XP-47B Thunderbolt prototype 40-3051 at Farmingdale, New York, 1941. The pilot standing in front of the airplane gives a scale reference. (Republic Aviation Corporation)
Kartveli submitted his design proposal for the XP-47B to the U.S. Army Air Corps, 12 June 1940. The prototype was ordered 6 September, and a week later, 13 September 161 production P47Bs and 602 P-47Cs were ordered. The contract was for $56,499,924. The company named the new fighter “Thunderbolt,” which had been suggested by C. Hart Miller, director of the military contracts division of Republic Aviation.
The XP-47B was the largest single-engine fighter that had yet been built. The production P-47B was 34 feet, 10 inches (10.617 meters) long with a wingspan of 40 feet, 9-5/16 inches (12.429 meters), and height of 12 feet, 8 inches (3.861 meters).¹ The wing area was 300 square feet (27.9 square meters). At a gross weight of 12,086 pounds (5,482 kilograms), it was nearly twice as heavy as any of its contemporaries.
Republic XP-47B Thunderbolt 40-3051 at Wright Field, Dayton, Ohio.(Ray Wagner Collection, San Diego Air & Space Museum Archives )
The XP-47B was powered by an air-cooled, supercharged and turbocharged, 2,804.4-cubic-inch-displacement (45.956 liter) Pratt & Whitney R-2800-21 (Double Wasp TSB1-G) two-row, 18-cylinder radial with a compression ratio of 6.65:1 had a normal power rating of 1,625 horsepower at 2,550 r.p.m., to an altitude of 25,000 feet (7,620 meters), and a takeoff/military power rating of 2,000 horsepower at 2,700 r.p.m. at 25,000 feet (7,620 meters). The engine drove a 12-foot, 2 inch (3.708 meter) diameter, four-bladed Curtiss Electric constant-speed propeller through a 2:1 gear reduction. The R-2800-21 was 4 feet, 4.50 inches (1.340 meters) in diameter and 6 feet, 3.72 inches (1.923 meters) long. The engine weighed 2,265 pounds (1,027 kilograms). Approximately 80% of these engines were produced by the Ford Motor Company. It was also used as a commercial aircraft engine, with optional propeller gear reduction ratios.
A large General Electric turbosupercharger was mounted in the rear of the fuselage. Internal ducts carried exhaust gases from the engine to drive the turbocharger. This supercharged air was then carried forward through an intercooler and then on to the carburetor to supply the engine. The engine’s mechanical supercharger further pressurized the air-fuel charge.
Republic XP-47B 40-3051. The pilot enters the cockpit through a hinged canopy segment. (Ray Wagner Collection Catalog, San Diego Air and Space Museum)
During flight testing, the XP-47B Thunderbolt demonstrated speeds of 344.5 miles per hour (554.4 kilometers per hour) at 5,425 feet (1,654 meters), and 382 miles per hour (615 kilometers per hour) at 15,600 feet (4,745 meters). Its maximum speed was 412 miles per hour (663 kilometers per hour) at 25,800 feet (7,864 meters). The test pilot reported that the engine was unable to produce full power during these tests. It was determined that it had a cracked cylinder head, resulting in a loss of 2.5–4% of its maximum rated power. Also, the XP-47B was painted in camouflage, resulting in a slight loss of speed.
It could climb to 15,000 feet (4,572 meters) in just five minutes.
The Thunderbolt was armed with eight Browning AN-M2 .50-caliber machine guns, four in each wing, with 3,400 rounds of ammunition. It could also carry external fuel tanks, rockets and bombs. The structure of the P-47 could be described as “robust” and it was heavily armored. The amount of damage that the airplane could absorb and still return was remarkable.
Republic XP-47B Thunderbolt 40-3051, 4 May 1941. (Republic Aviation Corporation)
During a test flight, 4 August 1942, the XP-47B’s tail wheel was left down. The extreme heat of the turbocharger’s exhaust set fire to the tire, which then spread to the airplane’s fabric-covered control surfaces. Unable to control the airplane, test pilot Filmore L. Gilmer bailed out. The prototype Thunderbolt crashed into Long Island Sound and was destroyed.
The third production Republic P-47B Thunderbolt, 41-5897, at Langley Field, Virginia, 24 March 1942. The door-hinged canopy of the XP-47B has been replaced by a rearward-sliding canopy, requiring that the radio antenna mast be moved.(NASA)A Republic P-47B Thunderbolt in the NACA Full Scale Tunnel, 31 July 1942. (NASA LMAL 29051)
A total of 15,683 Thunderbolts were built; more than any other U.S. fighter type. In aerial combat, it had a kill-to-loss ratio of 4.6:1. The P-47, though, really made its name as a ground attack fighter, destroying aircraft, locomotives, rail cars, and tanks by the many thousands. It was one of the most successful aircraft of World War II.
¹ Data from Pilot’s Flight Operating Instructions, Technical Order No. 01-65BC-1, 20 January 1943
Aviation Cadet Raymond L. Knight, United States Army Air Corps. (U.S. Air Force)
MEDAL OF HONOR
RAYMOND L. KNIGHT
Rank and organization: First Lieutenant, U.S. Army Air Corps.
Place and date: In Northern Po Valley, Italy, 24-25 April 1945.
Entered service at: Houston, Texas. Born: Texas.
G.O. No.: 81, 24 September 1945.
Medal of Honor
Citation: First Lieutenant Raymond L. Knight on 24 and 25 April 1945 in the northern Po Valley, Italy, piloted a fighter-bomber aircraft in a series of low-level strafing missions, destroying 14 grounded enemy aircraft and leading attacks which wrecked 10 others during a critical period of the Allied drive in northern Italy. On the morning of 24 April, he volunteered to lead two other aircraft against the strongly defended enemy airdrome at Ghedi. Ordering his fellow pilots to remain aloft, he skimmed the ground through a deadly curtain of antiaircraft fire to reconnoiter the field, locating eight German aircraft hidden beneath heavy camouflage. He rejoined his flight, briefed them by radio, and then led them with consummate skill through the hail of enemy fire in a low-level attack, destroying five aircraft, while his flight accounted for two others. Returning to his base, he volunteered to lead three other aircraft in reconnaissance of Bergamo Airfield, an enemy base near Ghedi and one known to be equally well defended. Again ordering his flight to remain out of range of antiaircraft fire, Lieutenant Knight flew through an exceptionally intense barrage, which heavily damaged his Thunderbolt, to observe the field at minimum altitude. He discovered a squadron of enemy aircraft under heavy camouflage and led his flight to the assault. Returning alone after this strafing, he made 10 deliberate passes against the field despite being hit twice more by antiaircraft fire, destroying six fully loaded enemy twin-engine aircraft and two fighters. His skillfully led attack enabled his flight to destroy four other twin-engine aircraft and a fighter airplane. He then returned to his base in his seriously damaged airplane. Early the next morning, when he again attacked Bergamo, he sighted an enemy plane on the runway. Again he led three other American pilots in a blistering low-level sweep through vicious antiaircraft fire that damaged his airplane so severely that it was virtually nonflyable. Three of the few remaining enemy twin-engine aircraft at that base were destroyed. Realizing the critical need for aircraft in his unit, he declined to parachute to safety over friendly territory and unhesitatingly attempted to return his shattered airplane to his home field. With great skill and strength, he flew homeward until caught by treacherous air conditions in the Apennine Mountains, where he crashed and was killed. The gallant action of Lieutenant Knight eliminated the German aircraft which were poised to wreak havoc on Allied forces pressing to establish the first firm bridgehead across the Po River. His fearless daring and voluntary self-sacrifice averted possible heavy casualties among ground forces and the resultant slowing of the drive which culminated in the collapse of German resistance in Italy.
1st Lieutenant Raymond L. Knight with a battle-damaged Republic P-47D Thunderbolt fighter bomber. (U.S. Air Force)
Raymond Larry Knight was born 15 June 1922 in Houston, Texas. He was the third child of John Franklin Knight, a clerk, and Sarah Francis Kelly Knight. He attended John H. Reagan Senior High School in Houston, graduating in 1940.
Knight married Miss Johnnie Lee Kinchloe, also a 1940 graduate of Reagan High School, 5 June 1942. They had one son, Raymond Jr.
Knight enlisted as an aviation cadet in the United States Army Air Corps, 10 Oct 1942, and trained as a fighter pilot at various airfields in Texas. He graduated from flight school and was commissioned as a second lieutenant, May 1944. After advanced training, Knight was assigned to the 346th Fighter Squadron, 350th Fighter Group, 12th Air Force, at Tarquinia Airfield, Italy, in November 1944. He was promoted to first lieutenant in March 1945.
Lieutenant Knight flew 82 combat missions. He is credited with 14 enemy aircraft destroyed.
The Medal of Honor was presented to Mrs. Knight by Major General James Pratt Hodges at a ceremony at John H. Reagan Senior High School, 23 October 1945.
In addition to the Medal of Honor, Lieutenant Knight was also awarded the Distinguished Flying Cross, and the Air Medal with five oak leaf clusters (six awards).
The remains of 1st Lieutenant Raymond Larry Knight, United States Army Air Corps, are interred at the Houston National Cemetery, Houston, Texas.
1st Lieutenant Raymond L. Knight (at right) and crew chief Sergeant Marvin Childers, with Republic P-47D-27-RE Thunderbolt 42-26785, marked 6D5. This is the fighter bomber that he flew on the final mission. It was named “OH JOHNNIE” after his wife. (U.S. Air Force)
The Republic P-47 Thunderbolt was the largest single-engine fighter that had yet been built. The first P-47D variant was very similar to the preceding P-47C. The Thunderbolt which Raymond Knight flew on his final mission was a P-47D-27-RE, serial number 42-26785. He had named it OH JOHNNIE after his wife. The Thunderbolt’s bubble canopy had been introduced with the Block 25 series, and Block 27 added a dorsal fillet to improve longitudinal stability which had been diminished with the new aft fuselage configuration.
The P-47D-27-RE was 36 feet, 1¾ inches (11.017 meters) long with a wingspan of 40 feet, 9-3/8 inches (12.430 meters) The overall height was 14 feet, 7 inches (4.445 meters). The fighter’s empty weight was 10,700 pounds (4,853 kilograms) and maximum gross weight was 17,500 pounds (7,938 kilograms).
The P-47D-27-RE was powered by an air-cooled, supercharged and turbocharged 2,804.4-cubic-inch-displacement (45.956 liter) Pratt & Whitney Double Wasp TSB1-G (R-2800-59) two-row, 18-cylinder radial engine with a compression ratio of 6.65:1. The R-2800-59 had a Normal Power rating of 1,625 horsepower at 2,550 r.p.m. to 25,000 feet (7,620 meters) and a Takeoff/Military Power rating of 2,000 horsepower at 2,700 r.p.m. to an altitude of 25,000 feet (7,620 meters).¹ A large General Electric turbosupercharger was mounted in the rear of the fuselage. Internal ducts carried exhaust gases from the engine to drive the turbocharger. This supercharged air was then carried forward through an intercooler and then on to the carburetor to supply the engine. The engine’s mechanical supercharger further pressurized the air-fuel charge. The engine drove a 13 foot, 0 inch (3.962 meter) diameter four-bladed Curtiss Electric or Hamilton Standard Hydromatic propeller through a 2:1 gear reduction. The R-2800-59 was 6 feet, 3.72 inches (1.923 meters) long, 4 feet, 4.50 inches (1.340 meters) in diameter, and weighed 2,290 pounds (1,039 kilograms).
A flight of three Republic P-47 Thunderbolt fighters. (U.S. Air Force)
The P-47D had a maximum speed in level flight of 444 miles per hour (715 kilometers per hour) at 23,200 feet (7,071 meters) with 70 inches Hg manifold pressure (2.37 Bar), using water injection. The service ceiling was 40,000 feet (12,192 meters). It had a maximum range of 950 miles (1,529 kilometers) with internal fuel, and 1,800 miles (2,897 kilometers) with external tanks.
The Thunderbolt was armed with eight Browning AN-M2 .50-caliber machine guns, four in each wing, with 3,400 rounds of ammunition. It could also carry external fuel tanks, rockets and bombs. The structure of the P-47 could be described as “robust” and it was heavily armored. The amount of damage that the airplane could absorb and still return was remarkable.
A total of 15,683 Thunderbolts were built; more than any other Allied fighter type. In aerial combat, it had a kill-to-loss ratio of 4.6:1. The P-47, though, really made its name as a ground attack fighter, destroying aircraft, locomotives, rail cars, and tanks by the many thousands. It was one of the most successful aircraft of World War II.
¹ A rebuilt R-2800-63 was run at War Emergency Power (2,600 horsepower at 2,700 r.p.m.) for 7½ hours on a test stand, and was in running condition when the test was completed.
Lieutenant Colonel Leo Keith Thorsness, United States Air Force. (U.S. Air Force)
MEDAL OF HONOR
LIEUTENANT COLONEL LEO K. THORSNESS UNITED STATES AIR FORCE
Rank and organization: Lieutenant Colonel (then Major), U.S. Air Force, 357th Tactical Fighter Squadron
Place and date: Over North Vietnam, 19 April 1967.
Entered service at: Walnut Grove, Minn.
Born: 14 February 1932, Walnut Grove, Minn.
Citation: For conspicuous gallantry and intrepidity in action at the risk of his life above and beyond the call of duty. As pilot of an F- 105 aircraft, Lt. Col. Thorsness was on a surface-to-air missile suppression mission over North Vietnam. Lt. Col. Thorsness and his wingman attacked and silenced a surface-to-air missile site with air-to-ground missiles, and then destroyed a second surface-to-air missile site with bombs. In the attack on the second missile site, Lt. Col. Thorsness’ wingman was shot down by intensive antiaircraft fire, and the 2 crewmembers abandoned their aircraft. Lt. Col. Thorsness circled the descending parachutes to keep the crewmembers in sight and relay their position to the Search and Rescue Center. During this maneuver, a MIG-17 was sighted in the area. Lt. Col. Thorsness immediately initiated an attack and destroyed the MIG. Because his aircraft was low on fuel, he was forced to depart the area in search of a tanker. Upon being advised that 2 helicopters were orbiting over the downed crew’s position and that there were hostile MiGs in the area posing a serious threat to the helicopters, Lt. Col. Thorsness, despite his low fuel condition, decided to return alone through a hostile environment of surface-to-air missile and antiaircraft defenses to the downed crew’s position. As he approached the area, he spotted 4 MIG-17 aircraft and immediately initiated an attack on the MlGs, damaging 1 and driving the others away from the rescue scene. When it became apparent that an aircraft in the area was critically low on fuel and the crew would have to abandon the aircraft unless they could reach a tanker, Lt. Col. Thorsness, although critically short on fuel himself, helped to avert further possible loss of life and a friendly aircraft by recovering at a forward operating base, thus allowing the aircraft in emergency fuel condition to refuel safely. Lt. Col. Thorsness’ extraordinary heroism, self-sacrifice, and personal bravery involving conspicuous risk of life were in the highest traditions of the military service, and have reflected great credit upon himself and the U.S. Air Force.
Major Leo K. Thorsness and Captain Harold E. Johnson with their Republic F-105F Thunderchief, Takhli Royal Thai Air Force Base, Thailand, 1967. (U.S. Air Force)
AIR FORCE CROSS
CAPTAIN HAROLD EUGENE JOHNSON
Air Force Cross
The President of the United States of America, authorized by Title 10, Section 8742, United States Code, takes pleasure in presenting the Air Force Cross to Captain Harold Eugene Johnson (AFSN: 0-3116556/42372A), United States Air Force, for extraordinary heroism as Electronics Warfare Officer of an F-105 aircraft of the 357th Tactical Fighter Squadron, 355th Tactical Fighter Wing, Tuy Hoa Air Base, Vietnam, engaged in a pre-strike, missile suppression mission over North Vietnam on 19 April 1967. On that date, Captain Johnson guided his pilot in attacking and destroying a surface-to-air missile installation with an air-to-ground missile. Through his technical skill, he immediately detected a second missile complex and guided the pilot into visual contact. Diving into a deadly barrage of anti-aircraft fire, his aircraft bombed and successfully destroyed this site. In the attack on this second missile site, a wingman was shot down by the intense anti-aircraft fire, and the crew members were forced to abandon their aircraft. Flying through hostile missile threats, Captain Johnson’s aircraft engaged and destroyed a MiG-17 while attacking a superior MiG force. He aided in the rescue efforts for the downed crew, engaged additional MiGs, and damaged one in the encounter. Through his extraordinary heroism, superb airmanship, and aggressiveness, Captain Johnson has reflected the highest credit upon himself and the United States Air Force.
General Orders: Department of the Air Force, Special Order GB-363 (April 19, 1967)
Action Date: 19-Apr-67
Service: Air Force
Rank: Captain
Company: 357th Tactical Fighter Squadron
Regiment: 355th Tactical Fighter Wing
Division: Tuy Hoa Air Base, Vietnam
Major Thorsness and Captain Johnson flew this Republic F-105F-1-RE Thunderchief, 63-8301, on 19 April 1967. It was one of 61 F-105Fs that were upgraded to the F-105G Wild Weasel III configuration beginning in late 1967. It survived the Vietnam War, but was destroyed 20 December 1974 when, assigned to the 35th TFW at George AFB, California, it crashed at the Cuddeback Lake Gunnery Range after an engine failure. (U.S. Air Force)
A description of the air battle follows:
The first MiG kill of the day was recorded by Maj. Leo K. Thorsness, pilot, and Capt. Harold E. Johnson, Electronic Warfare officer (EWO), flying an F-105F. Thorsness’ flight consisted of four F-105F Wild Weasel aircraft, each plane being manned by a pilot and EWO and being specially equipped to locate and attack SAM sites. The flight was ahead of the main strike force and was committed to suppress SAM activity in the target area. About 8 to 10 MiG-17s attacked as the flight prepared to strike a SAM radar site with Shrike air-to-ground missiles. The Thorsness flight split up into three parts: the third and fourth aircraft entered into separate MiG engagements while Thorsness and his wingman continued the attack against the radar. The time was then about 4:55 p.m. Johnson provides an account of the encounter:
We found and delivered our ordnance on an occupied SAM site. As we pulled off the site heading west, Kingfish 02 ¹ called that he had an overheat light. He also headed west, and the crew, Majors Thomas M. Madison, pilot, and Thomas J. Sterling, EWO, had to eject from their aircraft. We headed toward them by following the UHF-DF steer we received from their electronic beepers and saw them in the chutes. . .
As we circled the descending crew, we were on a southerly heading when I spotted a MiG-17 heading east, low at out 9 o’clock position. I called him to the attention of Major Thorsness. . . .
Thorsness continued the story:
The MiG was heading east and was approximately 2,500 feet mean sea level. We were heading southeast and at 8,000 feet MSL. I began “S” turning to get behind the MiG. After one and a half “S” turns the MiG had progressed from the foothills over the delta southwest of Hanoi. The MiG turned to a northerly heading, maintaining approximately the same altitude and airspeed. Captain Johnson continued to give me SAM bearings, SAM-PRF [pulse recurrence frequency] status and launch indications as I continued to maneuver to attain a 6 o’clock position on the MiG.
The first burst of approximately 300 rounds of 20 mm was fired from an estimated 2,000–1,500 feet in a right hand shallow pursuit curve, firing with a cased sight reticle. No impacts were observed on the MiG. Within a few seconds we were in the 6 o’clock position with approximately 75 to 100 knots overtake speed. I fired another burst of approximately 300 rounds of 20 mm. I pulled up to avoid both the debris and the MiG. While pulling up I rolled slightly to the right, then left. The MiG was approximately 100 feet low and to our left, rolling to the right. The two red stars were clearly discernible, one on top of each wing, and several rips were noted on the battered left wing. We continued to turn to the left and after turning approximately 130° again sighted the MiG, still in a right descending spiral. Just prior to the MiG’s impacting the ground, Captain Johnson sighted a MiG-17 at our 6:30 position approximately 2,000 feet back. I pulled into a tighter left turn, selected afterburner, and lowered the nose. I again looked at the crippled MiG, saw it impact the ground in what appeared to be a rice field. After confirming the MiG had in fact impacted the ground I made a hard reversal and descended very near the ground, heading generally westerly into the foothills.
Thorsness then left the battle area, but returned after refueling to provide rescue combat air patrol during the search for his wingman’s aircrew. Thorsness and Johnson attacked another MiG and scored some damaging hits before they were themselves attacked by other MiG-17s. Although it is highly probable that Thorsness and Johnson destroyed a second MiG, this kill was not confirmed.
— Aces and Aerial Victories: The United States Air Force in Southeast Asia 1965–1973, by R. Frank Futrell, William H. Greenhalgh, Carl Grubb, Gerard E. Hasselwander, Robert F. Jakob and Charles A. Ravenstein, Office of Air Force History, Headquarters USAF, 1976, Chapter II at Pages 46 and 47.
Eleven days later, 30 April 1967, Major Thorsness and Captain Johnson were shot down by an AA-2A Atoll heat-seeking missile fired by a MiG-21 fighter piloted by Vũ Ngọc Đỉnh, 921st Fighter Regiment, Vietnam People’s Air Force. They ejected but were captured. Both men were held as Prisoners of War until 4 March 1973.
Colonel Leo Keith Thorsness, United States Air Force (Retired) died Tuesday, 2 May 2017, at St. Augustine, Florida. He was 85 years of age.
