Fighter Directors Against the Kamikazes - Chapter 13 of Radar and the Fighter Directors

By David L. Boslaugh, Capt USN, Retired

The Cherry Blossom

Even though in August 1944, the Commander-in-Chief of the Combined Japanese Fleet did not approve of aerial suicide attack tactics, the Yokosuka Naval Air Arsenal began work on a manned, rocket boosted glide bomb. It would be dropped from a mother-plane bomber. It is suspected that Vice Admiral Ohnishi, the later initiator of the special attack squadrons, supported the project and provided cover for it. The piloted bomb was named “Ohka”, meaning cherry blossom in Japanese, and in September an air group, the 721st, was established to formulate training and tactics for Ohka operations. This unit, set up at Konoike near the Arsenal, did not report to any of the naval air fleets, but rather to Imperial General Headquarters, from whom RADM Ohnishi apparently managed to keep the project secret. The 721st Air Group was issued twin-engine Mitsubishi G4M bombers with bomb bays modified to suspend the manned bomb under the fuselage. The unit was also issued its own protective fighters, mostly Zeros. By the end of October 1944, higher authority had accepted the concept of aerial suicide attack, and the air group came out of its cover. More about the cherry blossom later. [8, p.14, p.59]

Ohka (Cherry Blosom) manned bomb. Once released from the G4M mother plane, the pilot could activate his rocket engine to gain speed and extend range. National Museum of the US Air Force photo, Source: Wikimedia Commons


Preparation for Final Assault

The Island of Okinawa in the Ryuku Islands chain is only 340 miles from the Japanese homeland, and a perfect spot as a base for air operations to support the planned invasion of Japan, as well as a staging area for the invasion itself. To the Japanese it was essential to prevent the island’s capture at all costs. By early 1945, Japanese aircraft carrier air power had all but ceased to exist, and the aerial defense of Okinawa was going to depend on land based naval air power. The Japanese Navy’s 1st Air Fleet that had been in the Philippines was now in Formosa. The 3rd Air Fleet, responsible for defending the Ryukyus, was now based on airfields ranging from near Tokyo to the Island of Kyushu at the southern tip of the homeland islands. The 11th Air Fleet was also based on Kyushu, and responsible for repelling amphibious forces trying to invade the homeland. Between the Army and Navy, the Japanese had more than 4,000 serviceable land based aircraft, and more were arriving from aircraft factories every day. Their main problems were a shortage of aviation gasoline and a lack of experienced pilots. The latter was made even worse because the gasoline shortage severely restricted flight training. [15, pp.139-140]

A Japanese aircrew awaits orders to deploy their Mitsubishi G4M with Ohka manned bomb slung below the bomb bay. U.S. Navy National Museum of Naval Aviation photo No. 1996.488.161.017

From February 1945 to April, Task Force 58 ranged along the Japanese homeland coast attacking airfields to reduce the air power that could oppose invasion force. Land based air was reduced by 528 aircraft at some cost, however. On 21 February, Kamikaze aircraft from Kyushu sank the light carrier Bismarck Sea, and five suicide Zeros damaged the fleet carrier Saratoga so severely that she spent the remainder of the war under repair. Three Yokosuka dive bombers managed to put one bomb into Yorktown on 16 March, but she was able to stay on station. On 19 March, while attacking airfields on Kyushu, the fleet carrier Franklin took two bomb hits from a conventional dive bomber that left the carrier without power less than fifty miles off the Japanese coast for almost a day. Expert damage control saved her, but she would spend the duration in a shipyard. Then on 20 March, a Kamikaze attack severely damaged the destroyer Halsey Powell. [15, pp.140-145]

On 10 February 1945, 721st Air Group equipped with Ohka manned bombs came under the command of Vice Admiral Matome Ugaki as part of his 5th Air Fleet, but he held the Ohkas in reserve until he found a target worthy of expending his Kamikaze pilots lives. On 21 March a snooper found the right target, an American carrier task group 320 miles at sea from Kyushu, and apparently without fighter protection. At noon, eighteen G4Ms, carrying Ohkas with volunteer suicide pilots, and accompanied by thirty protective Zeros, took off from Toizaki, Japan. The attack was not coordinated with any other attackers and showed up on the cruiser Vincennes radar as a single large raid at over 100 miles. Vincennes’ FDO notified Task Group 58.1 fighter director LT Charles Ridgway who immediately vectored airborne CAP to check out the raid, launched backup TG 58.1 fighters, and called on the other three task groups to launch fighters in support. As a result there were 150 Corsairs and Hellcats vectored out to meet the raid. Corsairs from the fleet carrier Bennington took on the fighter protection, shot down twenty of the Zeros, and prevented the rest from engaging twenty-four Hornet and Belleau Wood Hellcats that attacked the G4Ms. Intercept was fifty miles out from the main body, and all eighteen bombers fell before they could launch their manned bombs. This was at a cost of two USN fighters. Thus, it was found that the best defense against the cherry blossom was destruction of their mother planes before they got to launch point. [8, p.59] [16, p.219]

The Radar Picket Destroyers

On 1 April 1945, nearly 50,000 allied troops went ashore on Okinawa with almost no land or air opposition, in large part due to carrier air attacks on Japanese land based air. But this would not last. As a last resort Japanese commanders began preparations for a series of massed air attacks intended to eliminate U.S. Task Force 58 as well as the British Task Force 57 stationed between Okinawa and Formosa. Until late 1944 the standard carrier task force or task group formation for air defense had been a circle of carriers with 2000-yard radius positioned around a single fleet carrier at the center, usually the flagship. Around the carrier circle would be another ring at 4,000 yards made up of battleships, cruisers, and destroyers, all armed with AA weapons of various caliber. With the advent of the Kamikazes, Allied commanders realized this formation could not adequately defend against suicide attacks, in particular ships on the periphery could not give warning in time to prepare for low flying attackers. The solution was positioning destroyers fifty to sixty miles from the main body in the direction of expected air attack to give advance warning. In most cases communication relay picket destroyers would be stationed between the outer pickets and the main body. Ships stationed alone in such “picket” positions were obviously vulnerable to air attack, so the second part of the solution was constant daylight combat air patrols orbiting over the destroyers. These CAPs would be under control of specialized fighter direction teams assigned to the destroyers. These FD teams could also be assigned control of the standing task group CAP as directed by the task group FDO. Some of the destroyers were designated “Tom Cat” destroyers with extra CAP aircraft having the job of examining every returning carrier raid to make sure no kamikazes were sneaking in under cover of the returning planes as they circled the Tom Cat destroyer. Because of the hazardous nature of the isolated duty, other ships, such as landing craft with additional AA guns, accompanied the picket destroyers. [15, pp.145-147]

During the Okinawa campaign, fifteen radar picket stations were set up around the island, and they would be occupied by destroyers on a daily basis as decided by the OTC to cover the most likely direction of enemy aircraft approach. As far as possible, every picket was to have an assigned fighter direction team, and the stations were spaced so that the control of CAP prosecuting a particular raid could be easily passed from picket-to-picket. The ships usually steamed their assigned circles at fifteen knots, but the CO had discretion to change speed, especially to go to higher speed if attack appeared imminent. The picket destroyers were to maintain constant visual and radar searches. They were to have AA weapons manned and ready at all times, and were to open fire on any unidentified airplane that came within 12,000 yards whether they had a good fire control solution or not. The pickets were to report all contacts to the OTC’s fighter director, and were to insure they got an acknowledgment for every transmission. They were to continuously guard nine different radio circuits, and all contacts were to be reported in terms of range and bearing from Point Bolo on Okinawa. Of the destroyer radar picket ships, in 1945 Commander Cruiser Division Six wrote:

In this operation it was necessary to station pickets at considerable distances (75 miles) from the center of the area in order to cover the most probable directions of approach of aircraft from enemy bases and at the same time to prevent approaching enemy planes from taking advantage of adjacent land masses. While the picket stations were close enough to each other to permit passing control of friendly fighters from one ship to another without losing contact, the stations were not close enough to permit mutual support against either air attack or surface raiders. Steps were taken to alleviate the condition by the assignment of an additional destroyer to each of the pickets in the "more vulnerable" stations and by stationing various small craft such as LCS's [Landing Craft Support] and LCI's [Landing Craft Infantry] in position to support the pickets. Nevertheless the attacks continued and severe damage and painful losses were incurred.

[53, pp.81-1-81-2]

Fifteen radar picket destroyer stations were located around the island of Okinawa during the invasion campaign. Their locations were specified in terms of range and bearing from Point Bolo on Okinawa, and picket destroyers were to stay within a radius of 5,000 yards from station center. Not all stations were occupied at one time, and the Officer in Tactical Command would specify on a daily basis which stations would be filled. From: (Radar Pickets 1945, Battle Experience, Radar Pickets and Methods of Combating Suicide Attacks Off Okinawa, March-May 1945 p.81-3)

Floating Chrysanthemum

From the first to the fifth of April, Japanese air put up only sporadic resistance to the Okinawa invasion, but things changed on the sixth with a series of massive coordinated air attacks the Japanese called Kikusui (floating chrysanthemum) in Japanese. These attacks were calculated to eliminate both the amphibious force ships in the anchorages and Task Forces 57 and 58. The first massed raid began on 6 April in the afternoon when 900 planes attacked in waves, of which a third were Kamikazes. Their score was two ammunition ships, three destroyers and one LST (Landing Ship Tank). The waves continued the following day damaging the carrier Hancock and the battleship Maryland. Task Force 58 pilot’s score was 249 aircraft claimed downed. [15, pp.149-150]

The next four days saw more sporadic attacks by groups of about twenty planes composed of both Kamikazes and conventional attackers, but on the eleventh, the second Kikusui of 150 fighters, 45 torpedo planes and 185 suiciders came in. This attack also lasted two days, and on 12 April Mitsubishi G4M bombers launched nine Ohka manned bombs. At 1445 the picket destroyer Mannert L. Abele on Okinawa Picket Station Fourteen was hit by a suicide Zero, and one minute later the ship was hit by the first Ohka to be launched in anger. It exploded in her forward boiler room, and the ship sank in three minutes, 79 men going down with her. She would be the first and only ship sunk by the cherry blossom. During those two days, RADM Clark noted that his Task Group 58.1’s fighters splashed eighty enemy planes, and credits his task group FDO’s, LT Charlie Ridgway, “brilliant fighter direction and concise instructions” as a prime contributor. [16, p.227]

While Mannert L. Abele was sinking, the destroyer Stanly on radar picket duty near Okinawa had just left her station to go to the aid of the picket destroyer Cassin Young that had just been hit by a Kamikaze. On the way, Stanly’s FDO took over the CAP that had been protecting Cassin Young and directed them to bring down six Aichi D3A dive bombers. While friendly fighters and Japanese attackers swirled above the two destroyers, another Ohka piloted bomb dove through the cloud of planes and headed toward Stanly. Its 500 mph approach speed was too great to give time to dispatch a fighter or to even train a gun on it. The Ohka’s momentum drove it through both sides of the bow and it exploded in the water clear of the ship. In a few minutes, another Ohka screamed over the mast close enough to tear away the ship’s American ensign, and then skip across the water until disintegration. The day’s casualties on Stanly were three men injured. [36, VI: p. 604] [8, p.59]

The Japanese launched the third Kikusui, consisting of 160 conventional and Kamikaze planes, on 16 April. They sank ammunition ships and minesweepers in the Okinawa anchorages, and twenty-two attackers gave special attention to the destroyer Laffey on Picket Station One. Laffey’s skipper, Commander F. Julian Becton, knew on the thirteenth that he would be going out to a picket station when he got a message directing him to go alongside the destroyer Cassin Young, anchored at Kerama Retto, to take aboard a fighter direction team. The team consisted of Lieutenants J. Vance Porlier and E. L. Molpus with three enlisted assistants. Laffey arrived on station on the afternoon of the fourteenth and that afternoon the FD team directed the CAP of a nearby destroyer on Station Three to bring down a group of three raiders. Later in the day they tallyhoed and sent eight more into the sea.

The fifteenth was quiet, but on the morning of the sixteenth, Laffey radarman Philip Nulf reported a huge formation approaching from the north. When CDR Becton looked at the radar screen he described it as so dotted that it looked like “an advanced case of chicken pox.” Fighter Directors, LTs Porlier and Molpus realized at once that they needed reinforcement for their four-plane CAP, and radioed the task force FDO aboard the amphibious force flagship Eldorado of their situation. He had ready fighters launched at once, but in the minutes it would take for the twenty-four Corsairs and Hellcats to reach Station One, Laffey would undergo an ordeal of Kamikazes. In addition to aircraft shot down by her marine Corsair CAP and by her landing craft escorts, Laffey’s gunners shot down nine Kamikazes. In contrast to instances where one bomb hit led to the sinking of an aircraft carrier, Laffey took four bomb and five Kamikaze hits and stayed afloat. On the same day, a group of 20 Kamikazes, including Mitsubishi G4Ms carrying Ohkas, and about twenty fighter escorts approached TF 58. CAP destroyed all attackers and most of the escort before they could reach the main body. On twenty-eight and twenty-nine April the Japanese staged the fourth Kikusui, this time against outer pickets and their escorts. None were hit, and in one instance six marine F4U pilots took on thirty Japanese fighters downing twelve. [4, pp.233-263] [8, p.68] [15, p.151]

The battleship Missouri about to be hit by a Japanese A6M Zero kamikaze, while operating off Okinawa on 11 April 1945. Fortunately for the forty mm quad gun crews, the plane hit the ship's side below the main deck, causing no more than a dent in the thick armor and a long scratch in the paint. The kamikaze pilot in the photo has been identified as either Flight Petty Officer 2nd Class Setsuo Ishino or Flight Petty Officer 2nd Class Kenkichi Ishii. U.S. Navy photo
A rather battered looking A6M3 Zero fighter flown by Japanese ace Hiroyoshi Nishizawa during the Solomon Islands Campaign 1943. The Zero was not an ideal suicide plane because of its very light structure which many times prevented it from penetrating a ship’s hull or superstructure, and thus causing its 550 Lb bomb to explode outside the ship (which was bad enough). Fires from ruptured gasoline tanks could also be horrendous. Japanese pilots put great emphasis on maneuverability in their fighters, which resulted in lowered structural strength, no armor plating, and no self sealing gas tanks. Some did not even carry radios. Imperial Japanese Navy photo, Source english wikipedia,

The next large scale attack came on three and four May, and again the main assault was on the Okinawa picket ships, sinking three destroyers and three landing craft. On the morning of four May, the destroyer-minelayer Shea was on Picket Station Fourteen twenty miles northeast of Zampa Misaki, Okinawa. At 0854 a single attacking G4M was spotted at six miles, and was dispatched by Shea’s FDO and protecting CAP. But another G4M carrying a piloted Ohka bomb was not spotted, and the rocket propelled bomb closed the ship at over 500 mph, hitting and passing through the bridge without exploding, but killing twenty-seven men in the process. The warhead exploded in the sea. On just one day, the fourth of May, 370 sailors were killed on Okinawa picket duty. [8, p.71] [36, VI: p.475] [15, p.152]

Eleven though thirteen May brought the sixth Kikusui, which caused severe damage to two picket destroyers as well as to the Task Force 58 flagship, the carrier Bunker Hill. One of the damaged destroyers, Hugh W. Hadley, had a miraculous survival story on the first day. While on Picket Station Fifteen northwest of Okinawa, her fighter directors were controlling CAP against a massive Japanese air attack on the invasion force when the ship was attacked by numerous Kamikazes, of whom she downed twenty with AA fire, but suffered a bomb and two Kamikaze hits, plus a hit by a manned Ohka bomb. Though severely damaged, her crew kept her afloat. Of the attack, Hadley’s fighter director wrote in his action report:

About 0800 this ship picked up a large bogey, 345 degrees, 100 miles from BOLO. Viceroy 11 and 13 at Angels 15 over Pt. Uncle were vectored out for an intercept as a single flight. Raid split at 30 miles from ship and CAP was split to intercept each half. Viceroy 13 tallyhoed six planes, Viceroy 11 tallyhoed 30 planes. Viceroy 13 quickly disposed of his six and went to the aid of Viceroy 11. Few, if any, of these planes escaped them. This is designated as Raid 1 on attached diagram. Raid 2, estimated 50 planes, flew directly over Pt. Uncle where Panamint's CAP of 8 planes engaged them. HEINE 1 was asked to send help and his planes orbiting Pt. Tare were directed to proceed to Pt. Uncle and vicinity and join the fray. No vectors were necessary. Raid 3, also appeared at this time and was on a course to pass to westward. Information was passed to Lowry in R.P. station 16 and he was asked to intercept it, which he did. His 4-plane CAP tallyhoed 20 enemy planes and effectively disposed of them. At the height of the combat, Raids 4 and 5 appeared. Raid 5 flew directly into the melee to the northeast of us and was engaged. It was impossible to vector any planes to meet it as none were left unengaged. At this time Viceroy 11-1 reported he was out of ammunition but he was staying on to do what he could. He shortly reported forcing one Betty into the water and set the pace for all planes to stand by. Several more planes were also forced down in this manner by pilots unknown. Raid 4 came in at the same time, passed by the melee intact and when 10 miles north of the ships, fanned out, circled the formation and attacked from all sides. This raid was opposed by RUBY 15 (two-plane R.P. patrol) only. Some enemy planes were shot down and a coordinated attack was partly broken up, but the majority of these planes got through to the ships and were mostly destroyed by AA gunfire. Both RUBY 15 planes began picking off stragglers at the beginning of the action, then opposed Raid 4, estimated 20 to 30. When enemy planes closed, these two planes came in with them. One very outstanding feat by one of these two planes (believed to be RUBY 15-1, but not verified) was that though out of ammunition, he twice forced a suicide plane out of his dive on the ship and the third time forced him into such a poor position that the plane crashed through the rigging but missed the ship, going into the water close aboard. This was done while all guns on the ship were firing at the enemy plane. The highest award for flying skill and cool courage is not too much for this pilot. His wingman also stayed at masthead height in the flak and assisted in driving planes away from the ship. At the time the ship was hit below the waterline, power failed, our VHF radios were already inoperative from antennas carried away by a diving plane, and all communications were lost except one SCR 610 battery operated emergency set on 34.8 M.C. However, only three bogeys were left airborne and they were all being harassed by the original CAP, now out of ammunition and low on fuel. It is believed these last planes were splashed by reinforcements coming from BOLO under control of RINGTAIL BASE. None escaped to return to Japan.

[8, p.73] [36, III; p.387] (53, pp.81-7-81-8)

Aboard Bunker Hill eleven of ADM Marc Mitscher’s staff were killed by the Kamikaze hit on the thirteenth, and the damage was so severe that Mitscher had to transfer his flag to the carrier Enterprise. Then next day, Enterprise took a Kamikaze hit, causing Mitscher to move his flag again to the carrier Randolph. Kikusui seven was staged from the twenty-third to the twenty-fifth of May, and the raids were getting smaller. The last massed attack was from twenty-seven to twenty-nine May, and the Japanese realized by then it was not going to work. They had airplanes, but they were running out of pilots, and those that were left would be needed for homeland defense. [8, p.73]

On 11 May 1945, the fleet carrier Bunker Hill, while off Kyushu, Japan, was hit by two Kamikazes in the space of thirty seconds, killing 389 men out of a crew of 2,600. National Archives photo # 80-G-323712

In retrospect, Commander Task Group 58.1, RADM J. J. Clark wrote that his group had come through the Okinawa campaign relatively unscathed. Only one of his ships, the fleet carrier Wasp had suffered damage, and he attributed the group’s good fortune principally to two factors: his extraordinary anti-aircraft gunners; and “Charlie Ridgway’s superb fighter direction.” Clark also noted that more than three hundred Ohkas had been launched against Allied sea forces in 1945, however, only five ever scored on ships, if you count Stanly’s ensign being carried away by a low flying Ohka. A number of Ohkas had been sent to Okinawa, but were never used because Allied bombing had disabled the airfields. [8, p.68] [16, p.219, p.229] [15, p.152]

An action report by Commander Task Force 58, RADM Marc Mitscher, telling of Kamikaze tactics during the Okinawa operation stated:

Fighter direction met its most strenuous test in the present Kyushu-Okinawa operations. Rarely have the enemy attacks been so cleverly executed and made with such reckless determination. These attacks were generally by single or few aircraft making their approach with radical changes in course and altitude, dispersing when intercepted and using cloud cover to every advantage. They tailed our friendlies home, used decoy planes, and in at any altitude or on the water. Only once during the entire present operation did the enemy attack in the old orthodox fashion. Here a raid of 32 Bettys with 16 fighters as cover stacked 14-18,000 feet was annihilated 60 miles from this force. Fighter Director teams and radar personnel operating in this task force were well trained and experienced and every effort was made to increase efficiency by practice and experience. Never before, however, have the limitations of our present equipment become so pronounced, and the enemy, fully aware of these limitations gained by experience and other means, made every effort to attack this force under the cloak of these limitations and with quite effective results.

RADM Mitscher’s report summarized the limitations of our air defense against the Kamikaze attack:

  • Even the new SM and SP height finding radars could not consistently detect low fliers in time to deploy fighters, especially of singles or small groups. When fighters were deployed, the attackers were usually so close that the CAP could get in only one pass.
  • There was an unusually high percentage of uncompleted interceptions against small formation Kamikazes at ranges beyond 50 miles because the CAP never sighted them. This was due to inability of height finding radars to reach beyond this range, and due to the two-degree bearing accuracy of SC-2 and SK radars that resulted in seven-mile distance errors at a range of 100 miles.
  • Present radars had difficulty in maintaining tracks on small groups or single attackers that made sudden changes in course, altitude and speed. Tracking was even more difficult when friendly aircraft were also in the picture.
  • The Japanese use of ‘window’ [deceiving paper] could be very effective.

[13, p.39]

Our most dangerous foes. Pilots of the 72nd Shinbu Squadron at Bansei, Kagoshima 26 May 1945 They range in age from seventeen to nineteen. Left to right: front row Tsutomu Hayakawa, Yukio Araki, Takamasa Senda back row Kaname Takahashi, and Mitsuyoshi Takahashi. Araki died the following day near Okinawa in a suicide attack on U.S. ships. He was seventeen. Government of Japan photo, Source: Wikimedia Commons,

Of the role of fighter direction in the Okinawa Campaign, Commander Cruiser Division Six wrote in his action report:

Fighter direction during this operation was well handled, particularly in view of the many new problems imposed on account of the large size and geographical location of the area in which our forces were operating. There were no surprise raids and the great majority of enemy planes which approached during daylight failed to reach the most vital targets in the transport area at the objective. The many successful interceptions resulted from splendid coordination of fighter direction by the Force Flagship and efficient work of numerous other vessels--especially the destroyer types which acted as radar pickets.

[53, p.81-2]

The Commanding Officer of the destroyer Mullany also summarized his impression of fighter direction during the campaign:

1. The OKINAWA operation has proven to be one demanding the utmost from radar and fighter direction doctrines. With sometimes as many as a dozen raids threatening at the same time and from both northwesterly and southwesterly directions, the reporting, interception, and splashing of the enemy has been well controlled and thorough. The stationing of pickets has resulted in complete radar coverage allowing very few "bogies" to penetrate the screen undetected. Most of the bogies approached low over the water, making early detection difficult. It is believed that enemy planes were landing on NAHA airfield during the initial stages of the operation, as "bogies" which appeared on the screen after dark would be tracked to the perimeter of OKINAWA and would then be lost without report of their being shot down.

2. The CAP has done an excellent job in keeping the figures high in the "splash" column, flying in difficult weather and until dark in several instances. The night CAP has proven valuable in many interceptions, but there is still much to be desired if control of the air at night is to be obtained. Night fighters were airborne occasionally with no attempt made at intercepting the night "hecklers". This shows a need for more specially trained intercept officers in the forward areas. With two operational airfields and qualified intercept officers present, there should be no excuse for not utilizing the night fighter to the utmost. Fortunately the Japs did not see the capabilities of a full-scale night bombing attack on KERAMA RETTO, where the anchorage was filled with damaged ships and other high-priority targets.

3. Special praise is in order for the FDO's on the Eldorado. The IFD net was very effectively used in handling the reports and assigning interceptions. At many junctures the patience of the FDO was strained by stations cutting in on his net, demanding air cover and making criticisms of the way a situation was being handled. Responsible parties should realize the FDO's job is not an easy one when large scale air attacks are forming. He is not required to provide air cover for every station when requested to do so. [53, p.81-21]M

After eighty-two days of fierce Japanese resistance, Okinawa fell to the invasion force on 22 June 1945. By early August there had been weeks of peace feelers between the Allied high command and the Japanese government, but the Japanese showed little interest because of the demand for their unconditional surrender. They were going to fight on in spite of intense fire bombing raids. The Allies were not looking forward to the invasion of the Japanese homeland. Based on the fanatical resistance Japanese defenders had shown so far, they knew it was going to be a prolonged and bloody campaign. Things began to change on 6 August 1945 when a Boeing B-29 Superfortress based on the captured island of Tinian dropped a uranium-based atomic bomb on the city of Hiroshima. Then on 9 August Nagasaki suffered a similar fate from a plutonium-based bomb. On 15 August the Japanese government agreed to the surrender terms, and on 2 September signed the surrender document aboard the battleship Missouri in Tokyo Bay.

Some historians later stated that though the A-bomb may have ended the war, it was radar that won the war. This may be giving radar too much credit, but it certainly conferred an advantage. Naval radar was not only used to detect and track air and surface targets, but also became a principal means of directing shipboard gun fire, and it was also employed very effectively in the new variable time fuses in AA projectiles. Search and height finding radars by themselves were not enough. At the WW II stage of electronics technology they needed skilled operators, plotting teams, and fighter directors to effectively use the huge amount of data that radar could provide. And of course, it was the fighter pilots in the air who were the spear point of the air defense team.

Why did not the Germans and Japanese take full advantage of radar technology? Both nations had radar development projects that probably could have produced radars as good as, and on the same scale as, the Allies, but they chose not to do so. Most military historians have concluded that it was their military ethos of rapid offensive conquest, and their perception of radar as a defensive tool that made it beneath their dignity. Both nations produced radars in limited numbers, but only too late did they realize its importance.

Thanks to lessons learned from wartime experience, by lengthened and improved FDO training school curricula, and by constantly improved equipment and facilities, naval fighter direction continuously improved during the final year of the Pacific conflict. As from the beginning, the greatest frustration seemed to be with the fighter director’s facilities and equipment. There had been times during the massed Japanese air attacks of the Okinawa Campaign when fighter direction teams had been forced to the limits of their capabilities. They found repeatedly that their greatest difficulty was the inability of the teams to effectively use all the data that their radars could potentially provide. The narrow beam height finding radars were especially frustrating in a high volume raid because they had to be coached on their targets by the search radar operators. Then they had to be stopped to take measurements before being advanced to the next target. In general the FDO’s equippage served well in low volume attacks; their problem was in keeping up with the situation and maintaining a complete tactical picture in saturation raids. It was a task calling out for some sort of automated aid to the plotting teams and fighter directors.

In a secret letter on 8 October 1945 to the Chiefs of the Bureaus of Ordnance, Aeronautics and Ships the CNO, Admiral Ernest J. King, summarized the fleet’s needs for improved facilities and equipment. He called for:

  • Height finding radars that could measure altitudes at up to 150 miles range, without the need to stop the antenna, and with elevation accuracy on the order of forty to sixty minutes of arc.
  • Radars with consistent detection ranges beyond 300 miles on aircraft up to altitudes of fifty thousand feet.
  • Airborne radars with detection ranges of 100 miles on aircraft and missiles.
  • Airborne radars with sufficient accuracy to direct fighters to interceptions at ranges up to twenty miles.
  • Search radars that could discriminate and detect air targets over land masses, and regardless of atmospheric problems or “window” countermeasures.
  • Positive identification between friend and foe, and determination of individual unit or aircraft identity.

Of the problems in the display and handling of radar data, the CNO had this to say:

The display of information was slow, complicated and incomplete, rendering it difficult for the human mind to grasp the entire situation either rapidly or correctly and resulting in the inability to handle more than a few raids simultaneously. Weak communications prevented information from being properly collected or disseminated either internally aboard ships or externally between ships of a force.

He went on to say, what was needed was:

A method of presenting radar information automatically, instantaneously, continuously, and in such a manner that the human mind...may receive and act on the information in the most convenient form... instantaneous dissemination of information within ship and force.

It would take a while to meet the CNO’s challenge, and how that was done is another story. [13, p.41]

Click here to go to “ Epilog - What is the “Right Stuff” for a fighter director? - Chapter 14 of Radar and the Fighter Directors.”