Allison J71
# Allison J71

The Allison J71 was a single spool turbojet engine, designed and built in the United States. It began development in 1948 as a much modified J35, originally designated J35-A-23.

## Operational history

The Allison J71 turbojet powered the Douglas B-66 Destroyer and the McDonnell F3H-2 Demon after the failed Westinghouse J40 proved unworkable. The prototype P6M SeaMasters were also fitted with the engine.

## Variants

Data from: Aircraft engines of the World 1953

### J71-A-2

    Powered the McDonnell F3H Demon

### J71-A-2E

    9,700 lbf (43.15 kN) thrust (14,000 lbf (62.28 kN) thrust with afterburner), for the McDonnell F3H-2 Demon.

### YJ71-A-3

    7,000 lbf (31.14 kN) thrust (9,500 lbf (42.26 kN) thrust with afterburner)

### J71-A-4

    Afterburning turbojet engines for the Martin XP6M-1 Seamaster flying boat prototypes.

### J71-A-6

    Afterburning turbojet engines for the Martin YP6M-1 Seamaster pre-production flying boats.

### J71-A-7

    14,000 lbf (62.28 kN) thrust with afterburner

### J71-A-9

    Powered the Douglas RB-66 Destroyer

### J71-A-11

    10,200 lbf (45.37 kN) thrust

## Specifications (Allison J71-A-2)

Data from Aircraft engines of the World 1957

**General characteristics**

* Type: afterburning turbojet
* Length: 284.5 in (7,230 mm)
* Diameter: 39.5 in (1,000 mm)
* Frontal area: 8.5 sq ft (0.79 $m^2)$
* Dry weight: 4,890 lb (2,220 kg)

**Components**

* Compressor: 16-stage axial compressor
* Combustors: cannular with 10 flame tubes
* Turbine: 3-stage axial
* Fuel type: JP-4 / aviation kerosene
* Oil system: pressure spray with scavenge at 10–60 psi (69–414 kPa)

**Performance**

* Maximum thrust: take-off, dry 10,000 lbf (44,000 N); take-off, wet 14,000 lbf (62.28 kN)
* Overall pressure ratio: 8.0:1
* Air mass flow: 160 lb/s (73 kg/s) at 6,100 rpm (static)
* Specific fuel consumption: 1.8 lb/(lbf⋅h) (51 g/(kN⋅s)) with afterburner (wet)
* Thrust-to-weight ratio: 2.857
