Engine

The F-100D is fitted with the Pratt & Whitney J-57 turbojet engine featuring the J-57-P-21 and J-57-P-23 afterburner nozzles. The -21 was the legacy nozzle that suffered from extensive afterburner ignition issues, reliability, and efficiency problems. The -23 nozzle (originally produced for the F-102) fixed these issues.

At full military power, the J-57 produces apoproximately 10,200 pounds of thrust under standard conditions, and 16,000 pounds in maximum afterburner.

The F-100D Super Sabre requires external air to rotate the core in order to start the engine. Otherwise, pilots used a cartridge start mechanism to rotate the core at sufficient speeds without the use of external air.

Indications

Monitor the engine's status by reading the following four gauges toward the bottom-right of the instrument panel:

• Engine Pressure Ratio
• Tachometer (RPM)
• Oil Pressure
• Exhaust Gas Temperature (EGT)

Engine Pressure Ratio Gauge

The engine pressure ratio gauge shows the ratio between the turbine discharge pressure and the pitot pressure.

The gauge shows two adjustable values for takeoff and cruise pressure ratios. Pushing in and adjusting the knob adjusts the takeoff setting. Pulling out and adjusting the knob adjusts the cruise setting.

EPR Takeoff Index Settings

Set the takeoff indexer on the instrument based on the type of afterburner nozzle installed on the aircraft, and the external temperature as follows:

-21	-23	°F	°C
1.82	1.79	122	50
1.84	1.80	118	48
1.85	1.82	116	46
1.86	1.83	111	44
1.87	1.85	108	42
1.88	1.86	104	40
1.89	1.88	100	38
1.90	1.89	97	36
1.91	1.91	93	34
1.92	1.93	90	32
1.93	1.94	86	30
1.94	1.96	82	28
1.96	1.97	79	26
1.97	1.99	75	24
1.98	2.00	72	22
1.99	2.02	68	20
2.01	2.03	64	18
2.02	2.05	61	16
2.03	2.06	57	14
2.04	2.08	54	12
2.05	2.09	50	10
2.06	2.10	46	8
2.07	2.12	43	6
2.09	2.13	39	4
2.10	2.15	36	2
2.11	2.16	32	0
2.13	2.17	28	−2
2.14	2.19	25	−4
2.16	2.20	21	−6
2.17	2.21	18	−9
2.18	2.23	14	−10
2.20	2.24	10	−12
2.21	2.26	7	−14
2.22	2.27	3	−16
2.23	2.28	0	−18
2.25	2.29	−4	−20
2.27	2.30	−8	−22
2.28	2.31	−11	−24
2.29	2.32	−15	−26
2.30	2.33	−18	−28
2.32	2.34	−22	−30
2.34	2.35	−25	−32
2.35	2.36	−29	−34
2.37	2.37	−33	−36

Tachometer (RPM)

The tachometer registers engine speed in percentage of approximate maximum RPM (9980) of the high-speed compressor rotor.

Oil Pressure Gauge

The oil pressure gauge indicates oil pump discharge pressure above the gear case pressure in pounds per square inch.

Exhaust Gas Temperature (EGT) Gauge

The exhaust temperature gauge shows engine exhaust temperature in ° C.