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Gates Lear 25

lear25c
Lear 25C


The Learjet 25, first flown in prototype form on 12 August 1966, was basically a Learjet 24 incorporating a fuselage stretch of 1.27m to provide seating for the crew of two and eight passengers. The Lear 25 set the time-to-climb record to 40,000 ft at 6 min 19 sec.


Certificated on 10 October 1967, it was followed by improved Learjet 25B and Learjet 25C models in late 1970, the latter having additional 193 USG fuel capacity; thus, the Learjet 25B and Learjet 25C corresponded respectively to the Learjet 24E and Learjet 24F.


Gates certified its Century III 24/25 Learjets to cruise at 51,000 feet, higher by 5,900 feet than the max for any other FAA-certified commercial aircraft. Since pressurization failure at that altitude could be fatal no matter how enthusiastic one's emergency descent were, the FAA's certification tests were the same ones they'd planned to give the abortive Boeing SST- including firing pistols point-blank at the cabin windows.


In 1976 incorporation of the new cambered wing and aerodynamic improvements introduced simultaneously on the Learjet 24 models resulted in new Learjet 25D and Learjet 25F versions of the basic Learjet 25 and, similarly, all four Learjets became available later with General Electric CJ610-8A turbojets certificated for operation at an altitude of 15545m.


In addition to civil operations, a number of Learjet 25s were acquired by air arms, including those of Argentina, Bolivia, Ecuador, Mexico, Peru and Yugoslavia. Their primary role in most cases was for high-altitude photography and remote sensing, with a large single or dual integral camera pod just forward of the wing. Such aircraft were convertible easily for high-speed cargo or VIP transport duties. Manufacture of the Learjet 25F ended during 1979, but the Learjet 25D continued to be built until August 1982, when sales of the Model 25 had reached 368, when the growing recession in the aircraft industry caused its production to be suspended indefinitely in favour of the Learjet 35 and 36.

LR-25
Engines: 2 x GE CJ610-6.

LR-25B


LR-25C
Engines: 2 x General Electric CJ610-6 turbojets, 2,950 lbs thrust each.
Length: 47 ft 7 in.
Wingspan: 35 ft 7 in.
Speed: 545 mph.
Ceiling: 45,000 ft.
Range: 2,550 mls.

Lear 25D
Engines: 2 x GE CJ610-6, 2950 lb.
Seats: 10.
Wing loading: 64.7 lb/sq.ft.
Pwr loading: 2.54 lb/lb.
Max TO wt: 15,000 lb.
Operating wt: 8055 lb.
Equipped useful load: 6945 lb.
Payload max fuel: 847 lb.
Zero fuel wt: 11,400 lb.
Range max fuel/cruise: 1635 nm/3.5 hr.
Range max fuel / range: 1818 nm/ 4.4 hr.
Service ceiling: 45,000 ft.
Max cruise: 464 kt.
Max range cruise: 418 kt.
Vmc: 102 kt.
Stall: 93-118 kt.
1.3 Vso: 121 kt.
ROC: 6300 fpm.
SE ROC: 1725 fpm @ 220 kt.
SE Service ceiling: 23,500 ft.
BFL: 3937 ft.
Cabin press: 8.9 psi.
Fuel cap: 6098 lb.

LR-25D Learjet Century III 25D
Engines: 2 x General Electric CJ610-8A, 2950 lbs thrust.
Seats: 10.
Length: 47.6 ft.
Height: 12.3 ft.
Wingspan: 35.6 ft.
Wing area: 232 sq.ft.
Wing aspect ratio: 5.5.
Maximum ramp weight: 15,500 lbs.
Maximum takeoff weight: 15,000 lbs.
Standard empty weight: 8350 lbs.
Maximum useful load: 7150 lbs.
Zero-fuel weight: 11,400 lbs.
Maximum landing weight: 13,300 lbs.
Wing loading: 64.7 lbs/sq.ft.
Power loading: 2.5 lbs/lb.
Maximum usable fuel: 6098 lbs.
Best rate of climb: 6830.
Certificated ceiling: 51,000 ft.
Max pressurisation differential: 9.4 psi.
8000 ft cabin alt @: 51,000 ft.
Maximum single-engine rate of climb: 1910 fpm @ 220 kts.
Single-engine climb gradient: 521 ft/nm.
Single-engine ceiling: 23,500 ft.
Maximum speed: 475 kts.
Normal cruise @ 41,000ft: 452 kts.
Fuel flow @ normal cruise: 1088 pph.
Stalling speed gear/flaps down: 97 kts.

Lear 25F
Engines: 2 x GE CJ610-6, 2950 lb.
Seats: 8.
Wing loading: 64.7 lb/sq.ft.
Pwr loading: 2.54 lb/lb.
Max TO wt: 15,000 lb.
Operating wt: 7990 lb.
Equipped useful load: 7010 lb.
Payload max fuel: 0 lb.
Zero fuel wt: 11,400 lb.
Range max fuel/cruise: 1913 nm/4.1 hr.
Range max fuel / range: 2152 nm/ 5.2 hr.
Service ceiling: 45,000 ft.
Max cruise: 464 kt.
Max range cruise: 418 kt.
Vmc: 102 kt.
Stall: 93-118 kt.
1.3 Vso: 121 kt.
ROC: 6300 fpm.
SE ROC: 1725 fpm @ 220 kt.
SE Service ceiling: 23,500 ft.
BFL: 3937 ft.
Cabin press: 8.9 psi.
Fuel cap: 7391 lb.

LR-25G Learjet Century III 25G
Engines: 2 x General Electric CJ610-8A, 2950 lbs thrust.
Seats: 10.
Length: 47.6 ft.
Height: 12.3 ft.
Wingspan: 35.6 ft.
Wing area: 232 sq.ft.
Wing aspect ratio: 5.5.
Maximum ramp weight: 16,500 lbs.
Maximum takeoff weight: 16,000 lbs.
Standard empty weight: 8650 lbs.
Maximum useful load: 7850 lbs.
Zero-fuel weight: 11,400 lbs.
Maximum landing weight: 13,300 lbs.
Wing loading: 71.1 lbs/sq.ft.
Power loading: 2.8 lbs/lb.
Maximum usable fuel: 6638 lbs.
Best rate of climb: 5720.
Certificated ceiling: 51,000 ft.
Max pressurisation differential: 9.4 psi.
8000 ft cabin alt @: 51,000 ft.
Maximum speed: 464 kts.
Normal cruise @ 41,000ft: 452 kts.

 

 


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