Packard 1A-2500

American V-12 liquid-cooled aircraft engine

1A-2500

A preserved Packard 3A-2500 on display at the National Museum of the United States Air Force
Type	Liquid-cooled V12 engine
National origin	United States
Manufacturer	Packard
First run	1924
Number built	258

The Packard 1A-2500 is an American V-12 liquid-cooled aircraft engine designed by Packard in 1924 as a successor to the World War I-era Liberty L-12.^[1] Five aero variants were produced, of which the 3A-2500 was the most numerous. Three marine versions, used most prominently in American World War II PT-boats, the 3M-2500, 4M-2500, and 5M-2500, were also derived from it.^{[citation needed]}

Applications

Boeing TB
Heinkel HE 8
Martin T3M
Naval Aircraft Factory PN
Huff-Daland LB-1
PT boats - marine versions of the 3M/4M/5M-2500^{[citation needed]}
Packard-Bentley one-off race car
USSR World War II torpedo boats and sub-chasers, which were fitted with 535 4M-2500 engines with W-8 modification under Lend-Lease^{[citation needed]}

Variants

1A-2500: 1924, 800 hp. Six built.
2A-2500: 1925, 800 hp. 75 built.
2A-2540: ? Huff-Daland XHB-1
3A-2500: 1926, Geared propeller drive option, 800 hp. 175 built.
4A-2500: 1927, fitted with a supercharger, 900 hp. One built.
5A-2500: 1930, experimental use only, 1500 hp. One built.
3M-2500: Marine version^{[citation needed]}
4M-2500: Marine version, 1200 hp (895 kW), subsequently upgraded in stages to 1500 hp (1,150 kW).^{[citation needed]}
5M-2500: Marine version, larger supercharger, aftercooler, and power output of 1850 hp^{[citation needed]}

Engines on display

A Packard 3A-2500 is on display at the National Museum of the United States Air Force.^[2]
A Packard 3A-2500 is in storage at the National Air and Space Museum.^[3]
A Packard 3A-2500 is on display at the New England Air Museum.^[4]
A Packard 4M-2500 is on display at the Packard Proving Grounds Historical Site in Shelby Twp., Michigan.^{[citation needed]}
A Packard Series 142 Diesel Model 1D-1700 is on display at the Packard Proving Grounds Historical Site in Shelby Twp., Michigan.^{[citation needed]}
Three working Packard 5M-2500s are installed the only operational PT boat, Higgins PT-658 in Portland, Oregon.^{[citation needed]}

Specifications (1A-2500)

Data from Aircraft Engine Historical Society^[5] and Race With the Wind By Birch Matthews ^{[citation needed]}

General characteristics

Type: 12-cylinder V engine
Bore: 6+3⁄8 in (162 mm)
Stroke: 6+1⁄2 in (165 mm)
Displacement: 2,540 cu in (41.6 L)
Dry weight: 1,120 lb (510 kg)

Components

Valvetrain: Four valves per cylinder, overhead camshaft
Fuel type: Petrol
Cooling system: Liquid-cooled

Performance

Power output: 850 hp (630 kW) at 2,500 rpm
Specific power: 0.33 hp/in³ (15.2 kW/L)
Power-to-weight ratio: 0.76 hp/lb (1.25 kW/kg)

References

Notes

^ Gunston 1989, p.109.
^ "Packard 3A-2500". National Museum of the United States Air Force. 8 June 2015. Retrieved 26 June 2020.
^ "Packard 3A-2500 Geared Drive, V-12 Engine". National Air and Space Museum. Smithsonian Institution. Retrieved 26 June 2020.
^ "Packard 3A-2500". New England Air Museum. Retrieved 26 June 2020.
^ Aircraft Engine Historical Society - Packard Archived 2015-03-25 at the Wayback Machine Retrieved: 30 January 2009

Bibliography

Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9
Aircraft Engine Historical Society - Packard Engines
Matthews, Birch. Race With the Wind. Osceola, WI. MBI Publishing, 2001. ISBN 0-7603-0729-6