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F4D/F-6 Skyray: The Navy's Delta Wing Interceptor

History

In 1947 the U.S. Navy put out a requirement for a supersonic high-altitude interceptor. Douglas Aircraft Company designer Ed Heinemann developed the F4D Skyray. On June 17 Douglas Aircraft Corporation put forward their proposal. The D-571-1 plan had a delta wing which was a novel concept that interested the U.S. Navy. The Navy selected the D-571-1 plan for further development.[i]

The Navy gave Douglas a contract for two prototypes on December 16, 1949. The F4D prototype made its first flight on January 21, 1951. This was test pilot Larry Peyton’s first and last flight in a Skyray. Peyton was primarily a transport pilot and found the aircraft had some problems. Test pilot Russ Thaw took over flight testing the Skyray after Douglas corrected some of the issues Peyton found with the aircraft. [ii] Heinemann received the 1953 Robert J. Collier trophy for designing the Skyray.[iii]

On October 3, 1953 Lieutenant Commander James B. Verdin flew a Skyray to set an airspeed record of 752.9 mph (1,205 km/h). On October 15 Bob Rahn flew a Skyray on a 100-kilometer (62.1 mile) closed course at 728.11 mph (1,172.3 km/h) setting another speed record.[iv] On June 5, 1954 the first production F4D-1 became the first aircraft to sustain Mach 1 in level flight.[v] In May 1958 Marine Corps Major Edward N. LeFaive flying a Skyray set a time to climb record of 49,221 feet (15,000 meters) in 2 minutes and 36 seconds. This was one of a series of time to climb records Major LeFaive set in a F4D.[vi]

On November 19, 1958 Marine Corps Second Lieutenant Philip M. Schmitt was practicing an emergency landing at El Toro Marine Air Base. The F4D overshot the runway and crashed into the path of a passenger train. The train derailed. All 135 people on the train and 2nd Lt. Schmitt escaped serious injury.[vii]

In 1958 the Naval Ordinance Test Systems (NOTS) organization used a Skyray to launch a microsatellite into orbit. NOTS gave up after 6 unsuccessful attempts.[viii]

On October 21, 1960 a broken wire on a rudder caused an F4D-1 to crash. Lt. Jan M. Graves was killed in the accident.[ix]

The Navy deployed some Skyrays during the Cuban Missile Crisis but they were never involved in combat.[x] Skyraiders won some U.S. Navy and U.S. Air Force competitions where it competed against the most advanced U.S. interceptors of its day. The Department of Defense changed the Skyray’s designation from F4D to F-6 in September 1962. The Skyray was the first and last delta wing carrier aircraft for the U.S. Navy. It was also the last Douglas fighter accepted by the military. Douglas built 420 Skyrays.[xi]


[i] Military Factory.com, https://www.militaryfactory.com/aircraft/detail.asp?aircraft_id=638, last accessed 8/12/2020.

[ii] Airvectors.net, http://www.airvectors.net/avskyray.html, last accessed 8/13/2020.

[iii] National Air & Space Museum, https://airandspace.si.edu/collection-objects/awards-and-trophies-collier-robert-j-trophy-1950s-heinemann-edward-heisenhower, last accessed 8/13/2020.

[iv] Airvectors.net, http://www.airvectors.net/avskyray.html, last accessed 8/13/2020.

[v] Military Factory.com, https://www.militaryfactory.com/aircraft/detail.asp?aircraft_id=638, last accessed 8/12/2020.

[vi] Airvectors.net, http://www.airvectors.net/avskyray.html, last accessed 8/13/2020.

[vii] Madera Tribune, Volume 67, Number 136, 20 November 1958, https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=MT19581120.2.3&e=-------en--20--1--txt-txIN--------1, last accessed 8/15/2020.

[viii] Vectorsite.net, https://web.archive.org/web/20070805072633/http://www.vectorsite.net/avskyray.html, last accessed 8/15/2020.

[ix] China Lake Alumni.org, http://www.chinalakealumni.org/Accidents.htm, last accessed 8/15/2020.

[x] Airvectors.net, http://www.airvectors.net/avskyray.html, last accessed 8/13/2020.

[xi] Airvectors.net, http://www.airvectors.net/avskyray.html, last accessed 8/13/2020.

Background and Epilogue

Ed Heinemann’s inspiration for the Skyray was the designs of Dr. Alexander Lippisch. Dr Lippisch proposed some advanced concepts for high speed aircraft. These included the Me 163 Komet, tailless interceptor. Another Lippisch design was the DM-1 which had a delta wing.[i]

The Skyray showed the advantages and disadvantages of delta wing aircraft. The Skyray had excellent performance and good maneuverability at high speeds. The tradeoff was difficult handling at low speeds. Low speed handling difficulty is a big disadvantage for carrier-based aircraft.

With no horizontal tail, pilots used the elevons on the trailing edge of the wing to control pitch and roll. Pilots seemed to have a love it or hate it opinion of the Skyray.

As with most interceptors it had limited multirole capability. It didn’t have an air-air refueling system, which limited the Skyray’s range. The age of the interceptors ended with the 1960s. The last Skyrays on active duty were at the Navy Test Pilots School at Patuxent River, Maryland. Their purpose was to give pilots familiarity with how an unstable aircraft flew.

[i] “Delta” refers to the triangular shape, which is the symbol for the Greek letter delta.

F-6 Skyray vs MiG-19

SOURCES:
MiG-19 - Modern Fighters and Attack Aircraft by Bill Gunston (c) 1980 Salamander Books ltd.
F-6 Skyray - Airvectors.net

 F-6 SkyrayMiG-19

Max Speed

720 mph (Mach 1, 1,160 km/h)

920 mph (Mach 1.3, 1,480 km/h))

Max Range

1,200 miles (1,930km)

1,367 miles (2,200 km) with 2 drop tanks

Service Ceiling

55,000 ft. (16,800 m)

58,725 ft. (17,900 m)

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2020 Robert Sacchi

Comments

Robert Sacchi (author) on August 24, 2020:

It's amazing no one was killed in that plane/train accident. With fighters it is a tradeoff. A fighter plane has to be inherently unstable. The question is how unstable can it be before being too dangerous to fly. I read an interesting article that in an F-16 simulation between a computer and skilled pilots the computer won every time. That might be the next wave.

FlourishAnyway from USA on August 23, 2020:

The instability of the plane had to be daunting especially for a pilot still training. Certainly they need to be prepared for all kinds of situations and various aircraft. It would be frightening to be on that train that was hit. Thankfully no one was killed.

Robert Sacchi (author) on August 18, 2020:

Thank you for reading and commenting. The F4D and the F-6 are the same aircraft. The U.S. unified its designation system so they changed it from an exclusively Navy designation to a standard designation. India did show interest in the Skyray but decided against it. Most likely it was a good choice. The U.S. had many different fighters in the 50s and 60s. A lot of them had questionable records.

MG Singh emge from Singapore on August 18, 2020:

This is a nice article. Unfortunately my experience is not on American planes but on Russian planes staring from the MIG 21 and SU 7. I did have a stint in the Mirage. The MiG 19 I have seen in the museum in Russia but it was obsolete when I came in. There is not much written about the F4 and 6 but the more popular plane was the earlier generation F-86 ( sabre Jet).

Robert Sacchi (author) on August 17, 2020:

Thank you for reading and commenting. Yes, test pilots have to be brave. Their job is to find out any problems with the aircraft before it goes into mass production.

Fighter planes have to be unstable. A stable aircraft would lack the necessarily maneuverability. A comment in the article about them going to the test pilots school claimed some factiously said it was sent to teach the pilots to never let the Navy buy another plane like this one.

Peggy Woods from Houston, Texas on August 17, 2020:

Those first test pilots of new airplanes had not only to be experienced but also brave or daring souls.

Your last sentence is amazing to me: "The last Skyrays on active duty were at the Navy Test Pilots School at Patuxent River, Maryland. Their purpose was to give pilots familiarity with how an unstable aircraft flew." I guess learning about 'unstable' is as important as knowing a smooth operating aircraft.

Robert Sacchi (author) on August 16, 2020:

Thank you for reading and commenting. What's interesting is within a dozen years there was a jet aircraft, the SR-71, that could fly over 3 times the speed of sound.

Robert Sacchi (author) on August 16, 2020:

Thank you for reading an commenting. Aviation advanced a lot during World War II. At the beginning of the war the fastest fighter planes were about 350 mph. In 1944 there were planes flying 500-600 mph. More advanced aircraft were also on the drawing boards. The jet engine really opened the flight envelope.

Pamela Oglesby from Sunny Florida on August 16, 2020:

It is fascinating that this plane be could the first aircraft to sustain Mach 1 in level flight in 1958. I didn't realize that any plane was that avanced at that time. Thanks for another very interesting article about aviation hisotry, Robert.

Liz Westwood from UK on August 16, 2020:

I hadn't realised that aviation was so advanced 70 years ago.