# Pratt & Whitney R-1830 Twin Wasp
The **Pratt & Whitney R-1830 Twin Wasp** is an American 14-cylinder, two-row, air-cooled radial aircraft engine with a displacement of 1,830 cubic inches (30.0 L), produced from 1932 to 1951 in a total of 173,618 units by [Pratt & Whitney](https://www.edgepedia.org/pratt-and-whitney) and its licensees, more than any other aircraft engine.[1](https://www.enginehistory.org/Piston/P%26W/R-1830/r-1830.shtml) It powered two of the most-produced aircraft in history, the four-engined [Consolidated B-24 Liberator](https://www.edgepedia.org/consolidated-b-24-liberator) bomber and the twin-engined [Douglas DC-3](https://www.edgepedia.org/douglas-dc-3) transport and its military C-47 version, along with the Grumman F4F Wildcat fighter and the Consolidated PBY Catalina patrol aircraft.[1](https://www.enginehistory.org/Piston/P%26W/R-1830/r-1830.shtml)
| Key fact | Detail |
|---|---|
| Configuration | 14 cylinders in two rows of seven, air-cooled radial; bore and stroke 5.5 in (140 mm); displacement 1,829.4 in³ (30.0 L)[1](https://www.enginehistory.org/Piston/P%26W/R-1830/r-1830.shtml) • [2](https://airandspace.si.edu/collection-objects/pratt-whitney-twin-wasp-r-1830-90c-r-1830-s3c4-g-2-row-radial-14-engine/nasm_A19600115000) |
| First run / first delivery | First ran 16 April 1931; first production engine delivered to the U.S. Navy on 9 November 1932[1](https://www.enginehistory.org/Piston/P%26W/R-1830/r-1830.shtml) |
| Power range | Takeoff ratings from 630 to 1,350 hp depending on model; the R-1830-90C was rated 1,200 hp (895 kW) at 2,700 rpm[1](https://www.enginehistory.org/Piston/P%26W/R-1830/r-1830.shtml) • [2](https://airandspace.si.edu/collection-objects/pratt-whitney-twin-wasp-r-1830-90c-r-1830-s3c4-g-2-row-radial-14-engine/nasm_A19600115000) |
| Production | 173,618 engines built by Pratt & Whitney and licensees between 1932 and 1951, more than any other aircraft engine[1](https://www.enginehistory.org/Piston/P%26W/R-1830/r-1830.shtml) |
| Weight | 678.1 kg (1,495 lb) for the R-1830-90C[2](https://airandspace.si.edu/collection-objects/pratt-whitney-twin-wasp-r-1830-90c-r-1830-s3c4-g-2-row-radial-14-engine/nasm_A19600115000) • [3](https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/195797/pratt-whitney-r-1830-90c/) |
| Principal aircraft | Consolidated B-24, Douglas DC-3 and C-47, Grumman F4F, Consolidated PBY Catalina, Martin M-130, Short Sunderland[1](https://www.enginehistory.org/Piston/P%26W/R-1830/r-1830.shtml) • [4](https://airandspace.si.edu/collection-objects/pratt-whitney-twin-wasp-r-1830-92-radial-engine/nasm_A19750478000) • [5](https://canadianmuseumofflight.ca/2024/07/10/pw-r-1830-twin-wasp/) |
| Derived engine | The R-2000 Twin Wasp D, bored out to a 5.75 in bore, powered the Douglas DC-4/C-54[6](https://repo.poltekbangsby.ac.id/632/1/Air%2520Warfare_%2520An%2520Encyclopedia%25202%2520Volume%2520set%2520%2528%2520PDFDrive%2520%2529.pdf) |
## Development
Pratt & Whitney began work on a two-row radial in late 1929. The experimental 14-cylinder R-2270, built mostly from Wasp and Hornet parts, first ran on 14 May 1930 and was developed into the Twin Wasp, also a 14-cylinder two-row radial.[1](https://www.enginehistory.org/Piston/P%26W/R-1830/r-1830.shtml) The Twin Wasp design work began in 1931 under the guidance of the Pratt & Whitney engineer Luke Hobbs; the twin-row layout mounted 14 cylinders in two rows of seven on a forged aluminum crankcase, with liberal use of magnesium to save weight and attention to engine mounts to reduce vibration.[5](https://canadianmuseumofflight.ca/2024/07/10/pw-r-1830-twin-wasp/)
The Twin Wasp first ran on 16 April 1931, and the first production engine was delivered to the U.S. Navy on 9 November 1932.[1](https://www.enginehistory.org/Piston/P%26W/R-1830/r-1830.shtml) The engine was certificated in 1933, and its two-row layout opened a power market unreachable for single-row engines.[2](https://airandspace.si.edu/collection-objects/pratt-whitney-twin-wasp-r-1830-90c-r-1830-s3c4-g-2-row-radial-14-engine/nasm_A19600115000) The National Museum of the [United States Air Force](https://www.edgepedia.org/united-states-air-force) records the 1932 introduction ratings as 775 or 825 hp at 2,400 rpm, corresponding to compression ratios of 6.1 or 6.5.[3](https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/195797/pratt-whitney-r-1830-90c/) To reach its designed power the engine needed the highest-octane gasoline then available; with improved fuel it reached 1,000 hp and later 1,200 hp.[3](https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/195797/pratt-whitney-r-1830-90c/)
## Design
The R-1830 is a 14-cylinder, two-row, air-cooled radial with a bore and stroke of 5.5 in (140 mm) and a displacement of 1,829.4 in³.[1](https://www.enginehistory.org/Piston/P%26W/R-1830/r-1830.shtml) Each cylinder is built up from a cast aluminum head with integral valve mechanism housings, screwed and shrunk onto a forged steel barrel with integral fins; pressure baffles supply uniform cylinder cooling in all flight conditions.[1](https://www.enginehistory.org/Piston/P%26W/R-1830/r-1830.shtml) Exhaust valves are sodium-cooled and faced with stellite, and each cylinder has one intake and one exhaust valve actuated by ball-bearing rocker arms and push rods of heat-treated aluminum alloy.[7](https://mail.enginehistory.org/Piston/P%26W/R-1830/r-1830.shtml)
The two-throw one-piece crankshaft is supported by three roller bearings, and the propeller shaft runs within the crankshaft on a lead-copper pilot bearing, with a deep-groove ball bearing in the nose section absorbing propeller thrust.[1](https://www.enginehistory.org/Piston/P%26W/R-1830/r-1830.shtml) The planetary reduction [bevel gears](https://www.edgepedia.org/bevel-gear) are of Pratt & Whitney design with a 0.7625 ratio.[7](https://mail.enginehistory.org/Piston/P%26W/R-1830/r-1830.shtml) The crankcase is made up of six sections, with the nose section housing the reduction gears and, in geared versions, provision for a Hamilton Standard hydromatic full-feathering or other controllable propeller.[1](https://www.enginehistory.org/Piston/P%26W/R-1830/r-1830.shtml)
Induction runs from a Stromberg injection carburetor with automatic mixture control through the supercharger and diffuser passages, providing uniform distribution and improved performance at high altitude.[7](https://mail.enginehistory.org/Piston/P%26W/R-1830/r-1830.shtml) The basic engine used a single-stage, single-speed supercharger; beginning in 1936 Pratt & Whitney focused on the R-1830 with single-stage and two-stage or turbo-superchargers, and many later versions had two-speed supercharging along with turbo-supercharging for enhanced high-altitude performance.[2](https://airandspace.si.edu/collection-objects/pratt-whitney-twin-wasp-r-1830-90c-r-1830-s3c4-g-2-row-radial-14-engine/nasm_A19600115000) • [7](https://mail.enginehistory.org/Piston/P%26W/R-1830/r-1830.shtml) • [8](https://www.normsplash.com/Samples/SAE/918617881/R-154-en-2.pdf) Ignition comes from two Scintilla flange-mounted magnetos, each operating an independent set of spark plugs.[7](https://mail.enginehistory.org/Piston/P%26W/R-1830/r-1830.shtml)
## Service use
The Twin Wasp entered commercial service with the Martin M-130 China Clipper, whose trans-Pacific operations began in 1935; the 14-cylinder, 597 kW (800 hp) version powered that flying boat.[4](https://airandspace.si.edu/collection-objects/pratt-whitney-twin-wasp-r-1830-92-radial-engine/nasm_A19750478000) United Air Lines installed 746 kW (1,000 hp) Twin Wasps in its Douglas DC-3As, which entered service in 1937, and 9,600 Twin Wasp DC-3s were built for the military as the C-47, C-53, and C-117, the principal transports of World War II.[4](https://airandspace.si.edu/collection-objects/pratt-whitney-twin-wasp-r-1830-92-radial-engine/nasm_A19750478000) Pratt & Whitney alone built 13,464 R-1830-90C engines for the C-47.[3](https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/195797/pratt-whitney-r-1830-90c/)
Military users extended across the Allied air forces. The R-1830 powered the Consolidated B-24 Liberator, the [Grumman F4F Wildcat](https://www.edgepedia.org/grumman-f4f-wildcat) (the R-1830-86 was used in most early F4F-3s), the [Consolidated PBY Catalina](https://www.edgepedia.org/consolidated-pby-catalina), the [Douglas TBD Devastator](https://www.edgepedia.org/douglas-tbd-devastator), the Curtiss P-36, the Seversky P-35, and the Republic P-43.[1](https://www.enginehistory.org/Piston/P%26W/R-1830/r-1830.shtml) • [9](https://www.aircraftmanuals.aero/MENU_COMMON/SDETAIL.asp?mID=544) • [10](https://ww2aircraft.net/forum/threads/build-an-improved-gloster-f5-34.55772/page-3) British and Commonwealth aircraft included RAF Catalinas, Short Sunderland Vs, Martin Maryland bombers, and Bristol Beauforts.[3](https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/195797/pratt-whitney-r-1830-90c/) • [5](https://canadianmuseumofflight.ca/2024/07/10/pw-r-1830-twin-wasp/)
## Production and derivatives
From 1932 through 1951, output of the Twin Wasp by Pratt & Whitney together with its licensed manufacturers reached 173,618 units, a total exceeding that of any other aircraft engine.[1](https://www.enginehistory.org/Piston/P%26W/R-1830/r-1830.shtml) License production was granted to Buick and [Chevrolet](https://www.edgepedia.org/chevrolet) in the United States, to Commonwealth Aircraft in Australia, and, after World War II, to Flygmotorbolaget in Sweden.[5](https://canadianmuseumofflight.ca/2024/07/10/pw-r-1830-twin-wasp/) Wartime subcontracting followed the pattern Frederick Rentschler had established: Buick built the R-1830 Twin Wasp and the advanced R-2000 Twin Wasp, and Chevrolet built the Twin Wasp.[11](https://tile.loc.gov/storage-services/master/pnp/habshaer/mo/mo1900/mo1991/data/mo1991data.pdf)
The R-1830's constructive scheme remained almost unchanged over the years and supported dozens of models and sub-types, with power rising from about 650 hp in the first prototypes to over 1,350 hp in the latest models while the original dimensions stayed nearly unchanged.[12](https://www.museomotori.unipa.it/scheda.php?id=234&lang=en) Two direct derivatives enlarged the displacement: the R-2000 Twin Wasp D was an overbored R-1830 rated at 1,200 shp for the C-54 (DC-4), and the R-2180 Twin Hornet was a bored and stroked R-1830 rated at 1,150 shp for the DC-4E.[6](https://repo.poltekbangsby.ac.id/632/1/Air%2520Warfare_%2520An%2520Encyclopedia%25202%2520Volume%2520set%2520%2528%2520PDFDrive%2520%2529.pdf) The R-2000 was bored out to a 5.75 in (146 mm) cylinder bore with other changes to improve fuel economy and allow higher power ratings on lower-octane fuel.[13](https://www.youtube.com/watch?v=7_P-cav9OvU) Development of the Twin Wasp line eventually led Pratt & Whitney to the R-2800 Double Wasp, an 18-cylinder two-row radial introduced in 1939.[11](https://tile.loc.gov/storage-services/master/pnp/habshaer/mo/mo1900/mo1991/data/mo1991data.pdf)
## Legacy
The production total of 173,618 makes the R-1830 the most-produced aviation piston engine in history, a standing it owes partly to its use in the B-24 and the DC-3, two of the most-produced aircraft ever built.[1](https://www.enginehistory.org/Piston/P%26W/R-1830/r-1830.shtml) • [13](https://www.youtube.com/watch?v=7_P-cav9OvU) The engine is no longer manufactured, but it remains in regular service with fleets of DC-3s and a few remaining Canso (PBY) flying boats, and spares and second-hand engines are still traded.[5](https://canadianmuseumofflight.ca/2024/07/10/pw-r-1830-twin-wasp/) • [13](https://www.youtube.com/watch?v=7_P-cav9OvU) Surviving examples are displayed at the [National Air and Space Museum](https://www.edgepedia.org/national-air-and-space-museum), the [National Museum of the United States Air Force](https://www.edgepedia.org/national-museum-of-the-united-states-air-force), and the RAF Museum Midlands, among others.[2](https://airandspace.si.edu/collection-objects/pratt-whitney-twin-wasp-r-1830-90c-r-1830-s3c4-g-2-row-radial-14-engine/nasm_A19600115000) • [3](https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/195797/pratt-whitney-r-1830-90c/) • [14](https://www.rafmuseum.org.uk/research/collections/engine-pratt-whitney-r-1830-90d-twin-wasp/)
## References
1. [Pratt & Whitney Twin Wasp (R-1830), Aircraft Engine Historical Society, compiled by Kimble D. McCutcheon](https://www.enginehistory.org/Piston/P%26W/R-1830/r-1830.shtml)
2. [Pratt & Whitney Twin Wasp R-1830-90C (R-1830-S3C4-G), National Air and Space Museum](https://airandspace.si.edu/collection-objects/pratt-whitney-twin-wasp-r-1830-90c-r-1830-s3c4-g-2-row-radial-14-engine/nasm_A19600115000)
3. [Pratt & Whitney R-1830-90C, National Museum of the United States Air Force](https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/195797/pratt-whitney-r-1830-90c/)
4. [Pratt & Whitney Twin Wasp R-1830-92 Radial Engine, National Air and Space Museum](https://airandspace.si.edu/collection-objects/pratt-whitney-twin-wasp-r-1830-92-radial-engine/nasm_A19750478000)
5. [Pratt & Whitney R-1830 Twin Wasp, Canadian Museum of Flight](https://canadianmuseumofflight.ca/2024/07/10/pw-r-1830-twin-wasp/)
6. [Air Warfare: An Encyclopedia, entry on the R-1830 Twin Wasp](https://repo.poltekbangsby.ac.id/632/1/Air%2520Warfare_%2520An%2520Encyclopedia%25202%2520Volume%2520set%2520%2528%2520PDFDrive%2520%2529.pdf)
7. [P&W Twin Wasp (R-1830) description, Aircraft Engine Historical Society (mirror)](https://mail.enginehistory.org/Piston/P%26W/R-1830/r-1830.shtml)
8. [Pratt & Whitney, SAE historical publication](https://www.normsplash.com/Samples/SAE/918617881/R-154-en-2.pdf)
9. [P&W R-1830 Twin Wasp Maintenance Manual (part# 118610), March 1953](https://www.aircraftmanuals.aero/MENU_COMMON/SDETAIL.asp?mID=544)
10. [Build an improved Gloster F5/34, WW2Aircraft.net Forums (R-1830 supercharger development history)](https://ww2aircraft.net/forum/threads/build-an-improved-gloster-f5-34.55772/page-3)
11. [Pratt & Whitney Plant (Bannister Federal Complex), HAER No. MO-118, Library of Congress](https://tile.loc.gov/storage-services/master/pnp/habshaer/mo/mo1900/mo1991/data/mo1991data.pdf)
12. [Pratt & Whitney R-1830 Twin Wasp, Museo dei Motori, University of Palermo](https://www.museomotori.unipa.it/scheda.php?id=234&lang=en)
13. [pratt & whitney r 1830 twin wasp, aircraft engine - youtube](https://www.youtube.com/watch?v=7_P-cav9OvU)
14. [Engine – Pratt & Whitney R-1830-90D Twin Wasp, RAF Museum](https://www.rafmuseum.org.uk/research/collections/engine-pratt-whitney-r-1830-90d-twin-wasp/)
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*Topic: Encyclopedia › Technology and the built world › Transport and spaceflight › Aviation › Aircraft › Airliners and civil transport aircraft › Early and piston-engine airliners › Piston airliner engines and propulsion technology*
*Initially written Sep 17, 2026 · Reviewed: Oct 15, 2026 · Edited: Oct 15, 2026; Oct 25, 2026 · Last review: Oct 15, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license