MiG Alley Korea War, the first jet vs. jet aerial warfare
February 20, 2012
The MiG-15 and F-86 make their debut
You will recall when we started this report that I posed the question why was MiG Alley so far up north, and to the northwest. Hopefully we all now understand why. Allied forces were way up there, the Chinese invaded and pushed the Allies south below the 38th parallel, they retook Seoul, and now they had extended logistics lines all the way back to China and the Yalu, logistics lines which the Chinese had to protect and the US had to destroy. The only way for the US to destroy these logistics lines was by air, by bombers and these bombers required fighter escorts.
While addressing the Chinese invasion, I took you through to December 1950, year’s end. Most of what I discussed had to do with action on the ground. There was much going on in the background before December 1950 to address the air situation.
The Soviets, and by implication the Chinese, knew that that NKAF was no match for the USAF and Naval aviation, and something would have to be done. Well, the Soviets did do something.
They brought in the MiG-15 jet fighter, among the best air superiority aircraft in the world at the time, if not the best. Appearance of the aircraft at earlier air shows surprised the West. Their appearance in the Korean War came as a bit of a surprise, at least to General MacArthur, but the real surprise, that they were mostly flown by Soviet pilots was kept very secret by both the Soviets and Americans until many, many years later. That said, everyone knew the Soviets were the flying them and were the enemy.
A most interesting set of events followed.
John T. Correll, the editor of Air Force Magazine, wrote:
“In August 1950, a Soviet air division (the 151st Guards Fighter Division - GIAD) with 122 MiG-15 jet fighters arrived in northeastern China and were based at Antung on the Yalu River, the dividing line between Chinese Manchuria and North Korea.
“151st GIAD MiG-15s engaged UN forces for the first time in early November 1950. Shortly thereafter, the Soviets activated the 64th Independent Fighter Aviation Corps (IFAC) to engage UN forces in Korea, subordinate to the Commanding General (Aviation), (Soviet) Far East Military District.”
As an aside, Antung, also known as Andong, is now named Dandong. It is connected to Shenyang to the north by rail.
64th IFAC MiG-15s lined up at an air base in China.
The 324th Fighter Air Division (FAD) hosted the USSR’s most experienced pilots from WWII, especially good at taking down B-29s.
Danz Blasser, a senior analyst of a Korean War Working group, said:
“During the next two and a half years, a total of 12 Fighter Aviation Divisions, comprised of 34 Fighter Aviation Regiments, two independent Fighter Aviation Regiments, four Anti-Aircraft Artillery Divisions comprised of ten Anti-Aircraft Artillery Regiments, two Aviation Technical Divisions, two Anti-Aircraft Artillery Searchlight regiments, and a host of support units rotated through the 64th Fighter Aviation Corps.”
Antung, China and Sinuiju, North Korea (directly across the Yalu from Antung) were the two main MiG-15 bases on the Yalu in northwestern North Korea. Sinuiju was in North Korea and could be attacked, while Antung was just across the Yalu in Manchuria and, by the book, could not be attacked. Large formations of MiGs would fly in and out of Manchuria using it as a sanctuary.
US reconnaissance flights up in this area spotted the MiG-15s and reported not only their presence but the fact that they were flying in DPRK airspace. The US response was the F-86. We’ll introduce you to both aircraft, and then highlight the initial engagements.
Let’s take a look at both these aircraft.
First, the Mikoyan MiG-15.
The Germans during WWII had determined that the swept wing fighter was the best design for transsonic speeds, that is above the speed of sound at a range of Mach 0.8-1.2, or 600-900 mph. The US got the best German designers and most of them after WWII. But the Soviets did get some, and used German design plans and a few German aeronautical engineers they had captured to help them design the MiG-15.
British Rolls Royce engine in British plant.
To Stalin’s surprise, in 1946 the Soviets asked and the British provided technical information on their Rolls Royce Nene engines, the British licensed the Soviets to manufacture them, and allowed them to buy one engine.
A Soviet team visited the Rolls Royce plant. They were most interested in what the engine blades were made of. As they toured, they pressed their shoes hard against the shavings and took the shavings back to the USSR. By the time they purchased the engine, they already knew the composition of the alloy. This helped speed up Soviet reverse engineering of the engines. They were able to launch the engines into production and installed them in the MiG-15.
The first production model flew on December 31, 1948 and it entered service in the Soviet Air Force in 1949. The next variant entered service in 1950 with an improved engine, better placement for the 23 mm cannons on the undercarriage, and installation of under-wing hardpoints for unguided rocket launchers or bombs.
There were transsonic issues associated with tail design but these were solved. Another problem was it tended to go into uncontrollable spins. It also suffered from what one expert has called “wicked stall characteristics.” These latter two problems would haunt them through the war.
The MiG-15’s mission was to intercept and kill USAF B-29s which posed the strategic atomic threat to the Soviet Union. So the MiG-15 was to be an air defense fighter. And, it would be the B-29 that would cause them the most problems keeping their logistics and supply lines open. Here you see a B-29 over North Korea in a MiG-15’s sites.
The Soviets exported the MiG-15 to China. The MiG-15s were employed against the Chinese Kuomintang and on April 28, 1950 a MiG-15 piloted by a Soviet flier scored the MiG-15s first combat kill shooting down a Kuomintang P-38. Another MiG-15 also flown by a Soviet shot down a Chinese Nationalist B-24 Liberator on May 11.
Between November 1950 and December 1951, every MiG combat sortie had a Soviet pilot.
The major problem the American pilots faced with the MiG-15 is they knew precious little about it. They knew it could fly higher than their F-86 Sabre, they knew it was fast, they knew they flew in massive formations at high altitudes, they knew that they required ground intercept controllers to guide them, and, thankfully, they would learn after some missions that it was very unstable in a dive.
It took until 1953 for the US to get its hands on a MiG-15. This is an interesting story.
This picture of Lieutenant No Kum-Sok’s MiG-15 was in the estate of Airman Second Class Billy Oliver Shelor, who served with the 4th Fighter Interceptor Wing at Kimpo Air Force Base, Korea, from July 1953 to July 1954.
“On the day I landed and parked my MiG-15 next to the F-86, Captain Cipriano Guerra was sitting in the plane on alert. He got out of the plane and walked toward me between the two planes. Captain Guerra was the first American I met and shook hands with.”
Unfortunately, this acquisition was made two months after cessation of hostilities.
Yeager in the cockpit of the MiG 15. All of the gauges were based on the metric system, making them all virtually useless to him. He completed three missions in the airplane, logging 2 hours and 45 minutes of flying time. The USAF put US markings on the aircraft.
So now the US had a flyable MiG-15. Major Chuck Yaeger and Capt. H.E. “Tom” Collins got to fly it. Yaeger called it a “flying booby trap.” Having heard it was unstable in a dive, he put it into a dive and reached Mach 0.95. The aircraft buffeted about and was almost uncontrollable. Finally at about 3,000 ft. he managed to pull her out of the dive. Part of this handling problem, which existed at several speeds, was due to the MiG’s small aileron surface and lack of elevator effectiveness.
The MiG still had faster acceleration, and could climb faster and higher than the Sabre, attaining 45,000 ft. in nine minutes, while it took the F-86 13 minutes. The MiG-15 ceiling was 56,000 ft. while the F-86 could only get up to 51,000 ft. The MiG was at her best at combat at lower speeds where its lower thrust load allowed greater maneuverability. It could rapidly accelerate when at low speeds. It also had a short turning radius and short takeoff and landing requirements. The cockpit controlled systems needed a lot of attention, and the cockpit itself was prone to high heat at low altitude and chilling cold at high altitude. The cockpit canopy also decreased vision because of these inadequate heating and cooling systems and poor rearward visibility.
A nagging problem for the Soviet pilots was that they did not have G-suits that were needed in the hugh speed dogfights that demanded prompt and tight maneuvering. If they pulled high Gs, they were prone to blackout. This series of photos shows John Stapp riding in the “Sonic Wind” sled up to a speed of 421 mph in March 1954. He did not have a G-suit. You can see him black out in frame number 6. The G forces do most of their damage during acceleration. In most situations, both MiG and Sabre pilots flew fairly slowly until they entered combat, when they would suddenly accelerate to gain the advantage. That’s when G-forces would hit the Soviets hard. The Americans had G-suits to keep the blood flow in the upper half of their body instead of forcing it all downward.
The Soviet pilots were controlled from the ground and had to fly what became known as ground controlled intercepts, or GCIs. The GCI controllers were good and they received improved equipment, especially improved radar, and access to improved air defense artillery. The GCI controllers were able to position the MiGs very well, often at high altitude, where they would wait for the chance to attack the Sabre at lower altitudes. Unfortunately for them, US listening posts could monitor their transmissions and reconstruct their tactics. The constant conversations also gave away the fact that Soviets were flying the MiG.
The MIGs had the advantage of being close to home base for the MiG Alley fight, and could beat feet back if they got into trouble. We’ll talk about this later. The F-86 pilots were prohibited from chasing them into Manchuria, and we’ll address that later as well --- “Oh, did I cross into Manchuria?”
The MiG-15 also had better armament, two 23-mm and one 37-mm cannon.
Now a brief look at the North American F-86 Sabre.
The F-86 was America’s first swept-winged fighter. It was a bit faster than the MiG, but still transsonic. The Americans benefitted greatly from German aeronautical engineers who came to the US following WWII. German aerodynamic data showed that the swept wing was the only way to go. Investments in an aircraft known as the XP-86 delayed action on the new swept wing application. Unfortunately, the XP-86 could not reach speeds above 582 mph, not fast enough to meet military requirements. So modifications in the swept wing and other areas were made.
I want to highlight that the F-86A was the first to be sent to Korea. The F-86 rapidly went through a number of modifications taking her all the way up to the F-86F. Furthermore, a 6-3 wing kit was developed that deleted the leading edge slats and added a new solid leading edge with six more inches of chord at the root near the fuselage and three more inches in length at the wing tip. A high boundary layer “fence” was also added to the wing’s upper surface to 70 percent of wingspan to direct air flow. Changes were made to electrical, hydraulic and gun systems, the gunsight and other controls too numerous for me to track. The short story is that she was a pretty good aircraft when she first arrived, and within a couple years was one helluva aircraft just about equal to the MiG-15 and in many cases better.
Here are pictures of each model. I will leave it to you pros to spot the differences noticeable from the outside.
The XP-86 prototype, which would lead to the F-86, rolled out on August 8, 1947.
A note on the difference in engines between the MiG and Sabre. A jet engine gets its power from igniting fuel and air under tremendous pressure. There are different ways to compress the air.
The British Nene engine used by the MiG-15 compressed air with centrifugal force (blue area) inside the engine, propelling air outward through the to pressurize it, the the meeting with the fuel for combustion, and air forced out the rear powering the aircraft forward.
The F-86 engine was much like this graphic of a basic jet engine. It sucked air in through the front and compressed it and ignited it inside the engine and blew the air out the rear propelling aircraft forward. The F-86 engine, known as the General Electric J-47-GE-13, or “J47,” while much more efficient, unfortunately weighed more than the MiG-15’s. The MiG was simpler, and the structural components lighter, which allowed it to climb faster.
The F-86 made her maiden flight on October 1, 1947. She entered service with the Strategic Air Command (SAC) in 1949, assigned to the 22nd Bomb Wing, the 1st Fighter Wing and the 1st Fighter Interceptor Wing. In September 1948, the F-86 set a world speed record of 670 mph, and attained speeds later as high as 685 mph.
The F-86s delivered to Korea came in three models, the A, E and F. The F-86F, shown here, came off production in November 1952 and had a much more powerful engine, more streamlined leading edges on the wings and the size of the wings was increased. All together, it had improved aerodynamics and stability. The USAF now had an aircraft that could carry a great deal of fuel and still climb as well as the MiG and take on the MiG at much higher altitudes. BUt don’t sell the A model short. She was the first to get in a fight and held her own.
Two more fighter-bomber wings, the 8th and 18th, converted to the F86F in spring 1953.
A South African fighter squadron, the 2nd Squadron, also used it, flying with the 18th FBW.
The F-86 was produced to be a fighter-bomber and a fighter-interceptor. She could carry bombs, napalm and unguided rockets and was outfitted with fuel tanks that could be jettisoned. She carried M3 Browning machine guns which were later replaced by four 20 mm cannons capable of employing armor-piercing and armor-piercing incendiary rounds.
Her cockpit was far more comfortable than the MiG. The aircraft was far easier to handle as well. If a F-86 pilot got a MiG hot on his tail, his best defense was to dive. She handled very well in a dive, while as we mentioned the MiG did not handle well in a dive at all. Also, the Sabre had higher roll and turn rates than the MiG.
The Americans had G suits, known to the pilots as “speed jeans,” and these helped them enormously when in their steep dives. This photo is of a Korea War era G-Suit, which I believe actually were worn in WWII as well. The Navy used the one on the left, the USAF the one on the right. The top section was worn around the abdominal region, and the legs went through the other two sections. The pilot would tighten the suit outside the aircraft but not too tight; it should be loose and comfortable, and he should be able to bend over easily outside the aircraft. At high Gs, these inflated to hold the blood flow above the waist so the pilot would not blackout. The suit also reduced the need for the pilot to crouch when pulling high Gs. He could sit straight up and pay attention to what he saw outside his canopy. The suit also tended to eliminate fatigue during a dogfight and on long missions. The pilot would get into the cockpit seat and connect his suit to receive air pressure from the aircraft. That air pressure would start flowing when G forces exceeded 2.5 to 3.0 on the aircraft.
The pilots also liked their AN/APG-30 radar gunsights (a graphic of which is shown here), which gave them far greater accuracy and the system was easy to use. The pilot would line up his fighter so he could center the radar “pip”, or target image, in the gunsight circle. As the fighter banks, two gyros tilted a mirror device in the sight head; then the pilot would correct for mirror tilt by turning to center the “pip” while a computer supplied correct deflection. The “pip” glowed very brightly as the target came within shooting range at 2,000 yards.
The AN/APG-30 radar ranging unit was coupled with the A-1CM gun bomb and rocket sight. The F-86E was the first production-line aircraft in which the units were fit. For air-to-air work, the unit determines range, deflection, and any other factor necessary for good shooting. In the Korean War, the F-86 pilots felt they achieved results impossible with a conventional gyro sight. The unit was not small. It extended inside from the pilot through the fuselage nose all the way to the tip of the nose.
They later received the Sperry A-1C radar gunsight which had a range limiter on it which the pilot could set to 1000, 1200 or 1600 ft. The earlier gunsights did not have this range limiter.
John Boyd, who would retire an USAF colonel, was a fighter pilot who became a renowned theorist on aerial combat tactics. He developed the “E-M Theory” or “Energy Maneuverability Theory” to determine an aircraft’s specific energy rate. Basically, what the engineers put on paper is not always the way the aircraft ends up flying. Applying the E-M Theory to the MiG-15 and F-86, he concluded that the F-86 did so well against the MiG-15 because it had advantages from its fully hydraulic flight control system which the MiG did not have. Therefore it was more quick to transition from one maneuver to another. He said that the MiG was quicker and tighter in most maneuvers, but the F-86 pilot could get his aircraft in and out of any maneuver more quickly because of the F-86’s better hydraulics. This was especially true due to the fact that the F-86 pilot’s canopy gave him 360 degrees of view.
Boyd further developed a term nicknamed “OODA Loop,” which stood for “Observation, Orientation, Decision Action.” These were the steps necessary to any decision cycle. Whoever could go through these steps quicker had the advantage. With the F-86, a pilot could “get inside the adversary’s decision cycle” especially when getting inside the opponent’s loop or turn. Boyd would become a champion of maneuver, and using his calculations, the F-86 was better in this department than was the MiG-15.
This would help explain why most F-86 pilots would say how well the aircraft handled.
Later downstream, a fellow named John Penney, an air racer, said, “The F-86 has excellent control harmony, very good visibility, and good handling during landing approaches. It’s a lovely machine.” Penney would also say, however, that she was a “sensitive” aircraft at high speed, where, “Little tiny changes in pitch and roll produce rapid changes in altitude and bank angle.”
As an interesting aside, 5th AF pilots were initially worried that the MiG-15 and the F-86 were so much alike that they might confuse them in the heat of combat. I found one pilot’s story that certainly confirmed that, as he almost shot down one of his own aircraft.
Lt. J.A.O. “Omar” Lovesick, a Royal Canadian Air Force pilot on temporary duty with the 4th FIW, suggested doing what they did in WWII, marking the aircraft with stripes.
The 4th FIW took his suggestion to heart and put on fuselage bands angled toward the front of the aircraft. Stripes were also added to the leading edge of the rudder as a group marking.
The 51st Wing, of course, would not go the same route exactly. They painted black checkers on their vertical tail and became known as “The Checkertails.”
When the 18th entered the fray, it adopted a tail band like the 4th Wing but used dark blue with red or yellow borders.
Then came the 8th Wing. It retained its old “sunburst” tail stripes in the squadron colors, to go with the black and yellow bands.
I mentioned the “6-3” wing conversion kits earlier. Five “6-3” wing conversion kits were shipped to Korea in great secrecy in September 1952 to convert F-86Fs and eventually enough of these kits arrived to convert all F-86Fs and some F-86Es. This new wing configuration enabled the F-86 to reach speeds equal to the MiG-15 at altitudes up to 47,000 ft. The also allowed the F-86 to more easily turn inside the MiG.
The Russians were desperate to get their hands on a F-86, and standing orders were issued to try to get one down without having it crash. They went so far as to take a group of test pilots to practice “boxing” in a F-86 in order to force him to land. This group, however, would not make the cut and did not get to perform this maneuver. Instead, a Russian pilot pulled his aircraft up to an F-86 and hit the F-86 behind the cockpit, damaging the J-47 engine and ejection seat. The American, 2nd Lt Bill Garrett, pointed his aircraft toward the Yellow Sea and struggled with her.
Another Russian pilot was patrolling in a formation of four when he spotted Garrett and his struggle. He chased him to an altitude of 3,300 ft. and opened fire. Garrett worked to get away from the MiG but lost so much altitude that he was forced to ditch land in a mud flat along the coast. Fortunately, he was picked up promptly by a SA-16 amphibian in the area. F-86s above tried to destroy it but the MiGs fought them off. There was a three hour battle and the Russians lost seven MiGs in the fight, but they got their F-86, though it was no easy task to get it out of there. Ralph Wetterhahn has a great story on the subject, “To Snatch a Sabre,” which I commend to you.
The Russians took the Sabre to Moscow to assess the American technology and apply it to Russian fighter design. All the electronics were removed from the Sabre and sent to a laboratory for study. Among the major findings was that the F-86 employed a radar that provided range to target data that, when processed through a rudimentary computer, enabled the USAF pilot to portray his gunsight on his cockpit screen and fire quite accurately. In response, the Russians installed a radar warning device to alert the MiG pilot a F-86 was in the area and approaching from the rear.
Another finding when another newer model F-86 was captured was that the F-86 employed a horizontal stabilizer in the rear that moved as one piece. Previous versions moved as separate pieces on either side of the fuselage. The single piece adjustment is what enabled the F-86 to perform such controlled high speed dives when being chased.
I have concluded from my research that these were two fabulous aircraft for their time, and roughly equal, each having a few advantages over the other, but roughly equal. The difference turned out to be with the quality of the pilots. The Soviets were good, some were very good, the Chinese and North Koreans not so good; actually the latter were horrible. The Americans were top-of-the-line, free to fight on their own without GCI control, free to apply GI ingenuity that has always made US military forces so good.
MiG-15 and F-86 engagements
The Soviet piloted MiG-15s first engaged USAF aircraft in November 1950.
On November 1, 1950, six MiG-15s (Soviets say five) from the 72nd Guards Fighter Aviation Regiment (GIAP) intercepted a flight of USAF F-51 Mustangs in DPRK airspace. This was the first reported MiG-15 jet attack in Korean air space. The US said the USAF fighters managed to escape. The Soviets claim they shot down one Mustang. They said that a group of MiG-15s spotted ten F-80 Shooting Star aircraft at 4,500 meters altitude. They said that four F-80s were leading the overall flight in combat column order and a MiG-15 attacked these four. The other three F-80s reportedly chased the MiG-15s and the MiGs countered. The US fighters were said to have broken off the fight.
The Soviets claimed this to be the first jet air battle in history. The US side said a F-80 was lost that day in a raid against Sinuiju airfield but was shot down by Chinese anti-aircraft artillery (AAA) fire. The US analysis is conjecture, believing a second F-80 was shot down that day but its loss went without USAF comment. There was an engagement between MiG-15s and Mustangs but I have not seen any losses recorded.
I mention this only to underscore how hard it is to get a clear picture of who did what to whom during many of the fighter and homer engagements in this war. Statistics on fights between USAF and MiG-15 aircraft are confusing and in my opinion often shaky. Either record-keeping was very bad or tall stories were being told by crews or secrets were being kept, I don’t know. I just warn you to be careful when reading the stats. I tend to read the numbers to obtain a general descriptor of what happened.
On November 8 the Soviets said a force of 17 B-29s planned a mass strike on the city of Sinuiju and the bridges over the Yalu. Mustangs from the 8th Fighter Bomber Group (FBG) and F-80s from the 18th and 49th FBG attacked AAA positions in the area of the target. F-80s from the 51st Fighter Interceptor Group (FIW) provided top cover. Then six MiGs were spotted coming from Antung and attacked a flight of F-80s from the 16th Fighter Interceptor Squadron (FIS). The USAF aircraft turned to attack the MiGs and the MiGs turned around to leave, but one F-80 shot down one MiG.
The problem with this story is that the F-80 that chased that MiG experienced five out of his six guns jamming. A later analysis was that it would be very difficult for one machine gun to take down a MiG, and therefore the US conclusion later was that no MiG was shot down.
That said, I have seen US reports that an USAF F-80 encountered a MiG-15 and did shoot him down, and on November 7 a B-29 gunner shot down another MiG-15. As a matter of interest, while the F-80 was not really a match for the MiG in an air superiority role, it could turn inside the MiG and score some victories.
VF-111 F9F Panthers over Wonson
The conclusion that the USAF F-80 did not in fact shoot down the MiG on November 8 turns out be important historically. On November 9 a Navy F9F Panther jet from VF-111 “Sundowners” aboard the USS Philippine Sea (CV-47) is said to have scored the first jet-on-jet victory by shooting down a MiG-15 while providing cover for a propeller aircraft attack on bridges across the Yalu.
The pilot was LCmdr William Amen, shown here being congratulated after the flight. This was the first engagement between the MiG and a Panther.
Whatever the case here, the fact is that jet vs. jet aerial combat had begun. The fight was on.
Most US commanders thought the Chinese and NKAF were flying the MiG-15s. Given these early successes, they dismissed the MiG-15 as an overbearing threat even though the USAF knew they had nothing that could match it. It was a swept-wing jet fighter at least 100 mph faster than anything the USAF had at the moment, all of which was straight-winged.
Not only that, but the Soviets set up a three-nation command center at Antung and the Soviets were in charge. The Americans quickly learned the pilots were Soviet by monitoring their air-to-ground communications. The Soviet pilots were told to communicate in Chinese, but they had trouble doing that while flying and most often reverted quickly to speaking Russian. One Soviet pilot acknowledged often swearing in Russian during an engagement.
Colonel Pepelyayev would say:
“It was impossible psychologically in the heat of battle to use a foreign language you hardly knew. So after a week or two we just decided to ignore the order. The top brass started complaining, so I told them: ‘Go and fight yourselves!’ ”
The Soviets were told to wear Chinese uniforms. The Russian pilots did not like this, and off duty, switched into civilian clothes rather than wear the Chinese uniform. It should be mentioned that during the course of the war Polish pilots also flew the MiG-15 against the US.
I need to pause for a moment. The Soviets, fearing their secret of flying the MiGs in North Korea would come out into the open, worked to train the North Koreans and Chinese in the early months of the war. But they did not try very hard. The Soviets trained them to take off and land, but not how to fly fast or who to fly in combat. They taught them how to fly in formation and at altitudes up to 50,000 ft. But they soon learned they were up against a far better trained pilot in the American.
By way of summary, the US found itself up against tens of thousands of Chinese regulars on the ground and Soviet piloted MiG-15s to provide them air cover. The Chinese stopped the American offensive and MacArthur’s forces retreated to the south to positions at Suwon in the west, Wonju in the center, and an area north of Samcheok in the east, all of which were south of the 38th parallel and south of Seoul. One result was the enemy again crossed the 38th and retook Seoul.
The enemy, however, outran its logistics tail and could not proceed much beyond Seoul. So a battle line was formed. The US and its Allies counter-attacked and by March 14, 1951 retook Seoul from the enemy for the second time.
At this point, speaking at a top level, each side had a problem.
The Chinese and NKA forces that crossed south of the 38th parallel again had outrun their logistics, so it was crucial for them that their lines of communication stay open and very active to resupply them.
Given the entry of the Chinese into the war, one of the main targets for the USAF’s B-29s were those supply lines that came across the Yalu River from China into the DPRK. It was a cake walk for them as they went in and out unopposed, until the MiG-15 appeared, flying its first combat air patrols in November 1950. Not only did the MiG-15 show up with Soviet pilot, but the US had nothing on hand to counter either of them.
God must have been on the Allied side. The USAF had the North American F-86 Sabre, also a swept wing fighter. It was used for air defense of the homeland. This was the only fighter that had a chance against the MiG and it was sent to the fight.
The MiG, however, got into the action a month before the F-86s arrived, and during that time ruled the skies, a turn around from the era prior to their introduction. The F-51 Mustang was a good fighter, but could not match the jet. The F-86s and F-80s gave them a fight, but flew about 100 mph slower.
So the Russians had a bit of a field day. However, the F-86s arrived in November 1950 and went into combat almost immediately. They shot down six MiG-15s in a single engagement in December 1950.
The B-29 Superfortress and MiG Alley