The Lockheed XFV-1 Salmon: A Tail-Sitting Fighter That Never Took Off

The Lockheed XFV-1, nicknamed "Salmon" after its test pilot Herman “Fish” Salmon, was an ambitious experiment in vertical takeoff and landing (VTOL) aircraft. Developed in the early 1950s, it was part of a U.S. Navy program to create a ship-based VTOL interceptor that could operate from non-carrier vessels.

So, why was it built, what was its intended purpose, and why did it fail?

Why Was the Lockheed XFV-1 Built?

In 1950, the U.S. Navy sought a VTOL fighter to protect convoys and fleet assets from enemy aircraft. The goal was to:

✔ Operate from Small Ships – Deploy from vessels that lacked full-length flight decks.
✔ Provide Immediate Air Defense – Act as a quick-response interceptor against airborne threats.

To achieve this, the Navy explored tail-sitter aircraft, which could take off and land vertically on their tails like a rocket but transition into horizontal flight once airborne. Lockheed’s XFV-1 was developed to test this concept, along with its competitor, the Convair XFY-1 Pogo.

Photo Credit: airliners.net - Derek Ferguson

What Was Its Intended Purpose?

The Lockheed XFV-1 was designed as a VTOL ship-based interceptor, built to defend naval convoys without relying on traditional aircraft carriers.

✔ VTOL Capabilities – Could take off and land vertically, removing the need for runways.
✔ High-Speed Interception – Once airborne, it would transition to horizontal flight to engage enemy bombers and fighters.
✔ Ship-Based Deployment – Theoretically, it could operate from escort ships, supply vessels, or remote airstrips.

If successful, the XFV-1 could have revolutionized naval aviation, allowing smaller ships to field fighter aircraft without requiring a full-scale carrier.

Why Was It Never Mass Produced?

Despite its ambitious goals, the Lockheed XFV-1 Salmon never entered production due to several major challenges:

It Never Achieved Vertical Takeoff or Landing

• The aircraft was intended to take off vertically, but it lacked the necessary engine power to do so.
• Test flights began on June 16, 1954, but instead of vertical operations, the aircraft used a temporary conventional landing gear for horizontal takeoff and landing.
• Without its planned more powerful Allison T54-A-16 turboprop, true VTOL flight was never achieved.

It Was Extremely Difficult to Fly

• The tail-sitting design made landing especially difficult, as pilots had to descend backward with limited visibility.
• Pilots needed to control thrust, pitch, and balance simultaneously, making vertical landings extremely risky.
• The high cockpit position made it even harder to judge landing angles and descent speed.

Insufficient Engine Performance

• The aircraft used a temporary Allison YT40-A-6 turboprop, which did not produce enough thrust for full VTOL operation.
• Without sufficient power, the XFV-1 was unable to transition from hover to level flight, a critical requirement for VTOL aircraft.
• The planned T54-A-16 engine, which was supposed to correct these issues, was never delivered before the program was canceled.

Advancements in Carrier-Based Jet Fighters

• By the time the XFV-1 was being tested, conventional carrier-based fighters like the F-8 Crusader and F-4 Phantom were proving to be far superior in terms of speed, firepower, and practicality.
• The development of angled flight decks and steam catapults allowed conventional jets to launch and land more efficiently, reducing the need for VTOL fighters.

VTOL Technology Had Better Alternatives

• Helicopters, such as the Sikorsky HSS-1 Seabat, proved to be more practical for ship-based operations.
• Later, the Harrier Jump Jet provided a more feasible VTOL solution, using a thrust-vectoring jet engine instead of a tail-sitting design.
• The F-35B Lightning II, a modern VTOL jet, solved many of the problems that plagued the XFV-1.

By June 1955, the Lockheed XFV-1 program was officially canceled, and the aircraft never went beyond the prototype stage.

Photo Credit: jetprops.com

What Are the Takeaways from the XFV-1?

Though it never became operational, the Lockheed XFV-1 provided valuable lessons for VTOL aircraft development.

✔ VTOL Fighters Require Advanced Control Systems – The challenges of flying a tail-sitter fighter highlighted the need for automated flight controls to assist pilots.
✔ Engine Power Matters – The XFV-1's failure was largely due to insufficient thrust, proving that VTOL aircraft need powerful, reliable engines to be viable.
✔ VTOL Concepts Found Better Solutions – The tail-sitter idea was abandoned in favor of tilt-rotor aircraft, thrust-vectoring jets, and helicopter-based solutions.
✔ Ahead of Its Time – Much like the Nemeth Parasol and Stipa-Caproni, the XFV-1 was a bold but impractical design that aviation technology couldn’t fully support at the time.

Although the XFV-1 never entered production, it played a critical role in shaping VTOL technology, influencing future aircraft like the Harrier and the F-35B.

Conclusion: A Fighter That Never Took Off

The Lockheed XFV-1 Salmon was an ambitious attempt at creating a VTOL fighter, but it was ultimately too difficult to fly, underpowered, and outpaced by traditional jet fighters.

While its tail-sitting concept was bold, the difficulties of vertical flight, limited engine performance, and the rise of superior carrier-based fighters led to its cancellation.

Though it never became operational, the XFV-1 remains a fascinating relic of aviation history, a reminder of how ambitious engineering can push the limits of what’s possible—even if it doesn’t always succeed.

See More:

Wikipedia – Lockheed XFV-1 Salmon

Military History Matters – Back to the Drawing Board: The Lockheed XFV-1 Salmon

JetProps – The Lockheed XFV-1 Salmon: An Ambitious Attempt at VTOL