Lockheed XV-4 Hummingbird
Lockheed Corporation · United States · first flew 1962 · light aircraft
The Lockheed XV-4 Hummingbird was a US Army VTOL research jet that used a jet ejector augmentation system to achieve vertical takeoff and landing. It was an experimental aircraft investigating the feasibility of VTOL jet propulsion for military purposes.
Recognition (WEFT)
| W — Wings | Mid-mounted, straight |
|---|---|
| E — Engines | 2 × turbojet, fuselage-mounted |
| F — Fuselage | Two fuselage-mounted jets with lift augmentation ducts |
| T — Tail | T-tail |
WEFT is AircraftIQ's four-point recognition method — how it works.
Spot it by:
- US Army VTOL jet research aircraft
- Jet ejector lift system for vertical takeoff
- Two fuselage-mounted jets with lift augmentation ducts
Small mid-wing jet with two engine pods feeding both thrust and lift systems, a T-tail, and a single-seat cockpit. The fuselage contains complex ducting for the lift augmentation system.
Specifications
- The Lockheed XV-4 Hummingbird has a length of 9.96 m (33 ft).
- It has a wingspan of 7.82 m (26 ft).
- Its maximum speed is 833 km/h (518 mph).
- Typical crew: 1.
Figures are for the representative variant described above; marks differ. See how AircraftIQ sources figures.
History
Developed under a US Army contract, the XV-4 employed Pratt & Whitney JT12 engines whose exhaust could be diverted through an augmenter lift system for vertical flight. Two prototypes were built; the first flew in 1962. The aircraft proved the concept but suffered from a fatal crash of the first prototype in 1964. The second prototype (XV-4B) was modified with multiple lift jets and continued research until it too was lost in an accident in 1969.
Variants
The XV-4A was the initial version with the ejector-augmentor lift system. The XV-4B was extensively modified with eight small lift jets replacing the augmentor system, essentially becoming a different aircraft.
Where you'll see it
Strictly an experimental research programme with the US Army. Never entered operational service. Both prototypes were destroyed in accidents.
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