15 September 2006

Flightdeck Friday!

Douglas F3D Skynight

Mention “MiG Killer” and Korea in the same sentence and the F-86 justifiably springs to mind. That said, however, the F-86 was chiefly a day fighter and as the B-29’s shifted to night ops to gain presumed protection against the MiG-15, it rapidly became apparent that a night fighter was required to fill in the role of bomber escort. Requirements dictated a stable platform and a capable radar system, one that had excellent search capabilities as well as a fire control radar tied into the weapons system. This platform also had to have endurance, speed and range capabilities to stay with the bombers on their runs into the North and back.

Now, the above requirements were nothing new – indeed, during the latter stages of WWII the P-61 Black Widow, with all those characteristics, epitomized the night fighter. Fast, heavily armed with a good (for the time) radar system that was manned by a specialist, the P-61 extracted a toll worthy of its moniker. It was subsequently replaced by the P-82 Twin Mustang (see Mike’s excellent account here). However, the Twin Mustang, even though it drew first blood in the conflict, was too slow to deal with the emergent MiG threat. The solution lay in a jet platform and the Navy/Marine Douglas F3D Skykight was the choice.

During WWII, the Navy, no stranger to radar, had also experimented with night fighter techniques. Since the AEW version of the Avenger was not yet available (a product of Project Cadillac I), night section tactics were practiced with AI-radar equipped TBM Avengers and a section of F6F Hellcats. This was a difficult proposition and on one of the first missions of this type, LCDR Butch O’Hare, CMOH awardee and Enterprise’s CAG was lost, either to enemy action or friendly fire.

Mindful of its experiences in the latter stages of the war and with an eye towards the coming jet age, in 1946 the Navy contracted Douglas to build three prototypes of a carrier-based night/all weather fighter. Specifications included requirements for 500 kt top speed, 500 nm combat radius and 40,000 ft service ceiling. Some unique aspects were added – a dedicated radar operator would be seated beside the pilot and it would be powered by two jet engines mounted together under the wing roots. Crew escape would be through a (now infamous, thanks to the A3D) escape chute under the aircraft.

The first prototype flew in March 1948 and a limited run of 28 F3D-1’s was contracted for. These were delivered to VC-3 and VMF(N)-542 in 1950 (the latter being the Marine’s night fighter squadron). There were some shortcomings with the F3D, not entirely unique to jets of that time. It was underpowered as Douglas was expecting to use the more powerful Westinghouse J46 engines to replace the 3,000 lb thrust J34’s, but as described elsewhere, the J46 never saw the light of day due to development problems. Additionally, the -1’s suffered from a slow roll rate at high speed. This was fixed by the use of spoilers on the -2’s (which also received stronger, bulletproof windscreens, uprated electronics for the weapons system and provisions on the outboard wings for air-to-air missiles and rockets. With the uprated J34’s the -2s also saw an increase in top speed to 600 kts and range out to 1200 nm. The F3D-2 first flew in 1951 and saw over 237 produced.

The weapons system bears special mention in its own right. Comprised of three radars it provided an interesting set of cutting edge capabilities for its day. The AN/SPQ-35 was comprised of the AN/APS-21 X-band search radar, AN/APS-28 tail warning radar, and AN/APG-26 fire control radar, produced by Westinghouse. Standard practice was to use the APS-21 search radar to locate targets (a fighter-size target could be located and acquired at a range of about 20 nm). As the aircraft closed on the contact and it was acquired by the shorter-ranged APG-26 targeting radar (fighter-sized target @ about 2 nm), the radar operator would “hand-off” the target to the APG-26 and resume scanning for other targets while the pilot closed on the target using the APG-26’s return. Although crude by today’s standards, it nonetheless was an effective “track-while-scan” capability for 1950. Likewise, the APS-28 (fitted to the F3D-2) was also fairly sophisticated, with a range of 4 nm and the ability to give range, azimuth, and elevation information of targets approaching from the rear. It would prove exceptionally valuable in the night skies over Korea.

When war broke out on the Korean peninsula, VMF(N)-513 (USMC night/all weather fighter sqdn) was sent to Kunsan, Korea, with their Skyknights in the spring of 1952, where the F3D (also known at this point as “Willy the Whale” for its less than svelte figure) served with distinction.

One of the first missions it was put to use was for escort of B-29 formations. After suffering substantial losses to MiG-15’s in daylight raids, the B-29’s shifted operations to night. The advantage gained by darkness did not last long, however, as Soviet supplied (and manned) ground-control intercept radars provided close control for MiG’s flying night intercept missions against the B-29s. At first, the USAF tried to use the F-94 Starfire but its limited radar capabilities only allowed it to fly "barrier patrols" between the bombers and the MiG-15s coming in out of Manchuria. Soviet GCI could direct its interceptors into gaps in the coverage, so the MiGs could make a firing pass on the bombers and then withdraw north of the river before the F-94s could react. With little success and mounting B-29 losses, the Marines were called upon to provide escort. The enemy GCI could not distinguish between the B-29s and the F3Ds and with this advantage, the F3Ds racked up several night kills without a single loss.

On the night of 2 November 1952, a Skyknight piloted by Marine Major William Stratton, accompanied by radar operator Master Sergeant Hans Hoagland, shot down what they reported from the exhaust pattern to be a Yak-15 fighter, though the type was not known to be operated by the North Koreans. The kill was confirmed as the Skyknight flew through the wreckage of the target, narrowly evading damage. This was the first night kill of a jet by another jet. Five days later, on 7 November, another Skyknight under the command of Marine Captain O.R. Davis with radar operator Warrant Officer D.F. "Ding" Fessler shot down a MiG-15. (SJS: Note the Korean-era "poopy suit" anti-exposure suite -- this is the item of exquisite torture mentioned in Michner's Bridges at Toko-ri. The suit YHS flew in was not terribly different in execution or discomfort...)

Though the F3D seemed ungainly, any MiG that opted to get into a turning fight with the F3D soon found itself on the short end of the stick. The combination of the F3Ds weapons system and powerful main battery of 4 x 20mm cannon proved a lethal combination for enemy aircraft. The utility of the weapons system was proven on 10 December 1952, when Lt. Joseph Corvi’s F3D with radar operator Sergeant Dan George “splashed” a bogey using radar only to score one of the first BVR kills. The bogie turned out to be one of the little Po-2 biplanes used by the North Koreans to harass UN forces at night. The Po-2 was a difficult target, since it flew low and slow and its mostly wooden construction did not show up well on radar. In toto, Marine Skyknights claimed a total of at least six kills, most of them MiG-15s, and no B-29s under their escort were lost to enemy fighters. Two Skyknights were lost in combat for unknown reasons. Still, there were occasions that demanded extreme measures to prevent being shot down and the F3D’s ruggedness proved up to the task. In this instance, for example, Capt George Kross relates an experience from a January 1953 mission – this is the closest a Marine F3D came to being shot down by an enemy aircraft (SJS note: there were 7 total F3D losses for the war, none due to enemy fighter action):

"We were flying cover for a large formation of B-29s that was hitting targets
right on the Yalu. My tail-warning radar malfunctioned just about the time our
ground control radioed a 'heads-up' warning after picking up several fast-moving
MiGs that were in the vicinity of the bombers. We were above them at about
30,000 feet. Suddenly, I felt heavy cannon rounds impacting my aircraft, and I
immediately went into a split-S, with both throttles wide open. Within seconds,
I was able to get into a cloud layer that was about 10,000 feet below, under IFR
conditions and in a vertical dive!" With the Skynight's rear warning radar
out of commission, the MiG-15, which had been vectored in behind the night
fighter, was able to move into close range-thus the quick hits on Kross's F3D.
If he had had ample warning, he could have taken evasive action and reduced the chances of his being hit.

The extremely high airspeeds brought on by vertical dives often caused problems with the controls. "As I started to ease out of the dive, I didn't have any elevator response! I could move the control stick full forward and aft, yet nothing happened. My first thought was that the MiG's cannon fire had severed the control cables. I also noted that the airspeed indicator was far beyond the red `limited speed' marker; the airspeed hit about 750mph or Mach 1.02. The reason for my problem was that the aircraft was past the limiting Mach number, and the shock wave was blanking out the tail surfaces! I cut the throttle back to idle and put the speed brakes out. This caused an intense, longitudinal wallowing as the speed brakes would open, collapse and open full again."

"As my speed decreased, elevator control was regained. I went through several high-speed stalls in trying to round out my recovery, and I succeeded in returning to level flight below the overcast and dangerously close to the Yellow Sea. Indicated airspeed was about 400 knots, with idle throttle settings and dive brakes still fully extended. As we got into better weather conditions, I pulled up to 10,000 feet and went to slow flight and tried the landing gear and flaps; I executed a stall just to be sure that I would have full control in the landing approach to Kunsan AB."

The post-mission examination of Kross's aircraft and the conclusions that were drawn as a result were very interesting. The debriefing, in which Kross stated that the MiG followed him down in the high-speed dive and fired a few more rounds, led the experts to believe that the enemy pilot would not have been able to follow the evasive action of the F3D unless it was equipped with airborne radar. It just so happened that the magazine Aviation Week broke a story in its February 9, 1953, issue that confirmed night-flying MiG-15s were indeed equipped with radar, and this would pose an ever-increasing threat to night-flying UN aircraft.

As far as damage to Kross's aircraft goes, he and his R/O were lucky to live to tell about it. Inspection revealed numerous cannon holes in the tail and one hit between the two engines that cut through 19 fuselage stringers with final impact on the escape-hatch door located between the pilot and R/O. A hit in either engine would have been fatal to the F3D and crew.

Navy carrier-based use of the F3D was limited to near the end of the war. In part, this was due to the combination of smaller decks and need for multi-mission capable aircraft, like the F9F Panther. VC-4 (Det 44N) deployed four F3D-2 aircraft onboard USS Lake Champlain (CVA-39); the ship reaching Korean waters during the final months of the war. In the combat zone, the Detachment flew both carrier based and land based sorties while attached to VMF(N)-513.

In the years after the Korean War, the F3D was gradually replaced by more powerful aircraft with better radar systems. However, with its stability and spacious fuselage, the F3D was easily adaptable to other roles. The F3D (under the designations F3D-1M and F3D-2M) was used to support development of a number of air-to-air missile systems during the 1950s, including the Sparrow I, II, and III and Meteor missiles.

The F3D-2M was the first operational Navy jet aircraft to be fitted with an air-to-air missile, the Sparrow I, a missile that used beam riding guidance for the aircrew to control the flight of the missile. Only 38 aircraft (12 F3D-1Ms, and 16 F3D-2Ms) were configured for missiles.

In the late 1950s, a number of the Marine F3D-2 aircraft were re-configured as electronic warfare aircraft and were designated F3D-2Q (later EF-10B). Also, a few aircraft were converted for use as trainers and were designated F3D-2T.

Skyknights continued service through the 1960s in gull white color scheme, when their contemporaries had long since been retired. In 1962, when the U.S. Navy and U.S. Air Force unified their designation systems, the F3D-1 was redesignated F-10A and the F3D-2 was redesignated F-10B. EF-10Bs served in the electronic countermeasures role during the Vietnam War until 1969. The U.S. Marine Corps retired its last EF-10Bs in 1970. Some aircraft continued flying as testbeds for Raytheon until the 1980s.

When the U.S. Navy issued a requirement for a fleet defense missile fighter in 1959, Douglas responded with the F6D Missileer, essentially an updated and enlarged F3D that would carry the AAM-N-10 Eagle long-range missile. Douglas did not win the contract though and that was the beginning of the end of Douglas as an independent aircraft manufacturer. Not long thereafter, it merged with McDonnell to form the McDonnell-Douglas company (now since merged into Boeing).

Although it was the antithesis of the emerging concept of jet fighters in the 1950s, the F3D was an important pioneer in a number of fields – all weather interceptions, integrated weapons systems, weapons systems operators, dedicated electronics countermeasures aircraft, and more. Many later generation aircraft would be able to trace their roots back to some contact with the F3D. Among these were the F-4 Phantom, F-14 Tomcat and EA-6A Intruder and EA-6B Prowler. A generation or more of Radar Intercept Officers also received training in TF-10s. It also remains the only tactical jet to have seen combat in both Korea and Vietnam, as well as being deployed during the Cuban Missile crisis.

A total of 256 were built, but few examples remain today. Perhaps the best restored examples may be found onboard the ex-USS Intrepid’s museum and the National Museum of Naval Aviation in Pensacola, FL.

Specifications (F3D-2):

Power Plant: Two 3,400 lb Westinghouse J-34-WE-36/36A
Dimensions: Span 50'; length 45' 6
Weight: 26,850 lbs gross
Speed: 600 mph maximum
Range: 1200 miles


Next week -- we begin a series of articles that are tied into the development of AEW (Airborne Early Warning). During the weeks to come there will be a series of posts (about 1/week) that begin with Project CADILLAC and its precursors and lead up to today's AEW platforms. Filghtdeck Fridays will synch up with those posts and provide the stories of carrier- and shore-based AEW aircraft. So, next Friday -- the TBM-3W Avenger and the birth of carrier AEW.