Bristol Pegasus
R-9 piston aircraft engine family
The Bristol Pegasus is a British nine-cylinder, single-row, air-cooled radial aero engine. Designed by Roy Fedden of the Bristol Aeroplane Company, it was used to power both civil and military aircraft of the 1930s and 1940s. Developed from the earlier Mercury and Jupiter engines, later variants could produce 1,000 horsepower (750 kilowatts) from its capacity of 1,750 cubic inches (28 L) by use of a geared supercharger.
Further developments of the Pegasus created the fuel-injected Bristol Draco and the diesel Bristol Phoenix, both types being produced in limited numbers. In contrast, by the end of production over 30,000 Pegasus engines had been built. Aircraft applications ranged from single-engine biplanes to the four-engined Short Sandringham and Sunderland flying boats. Several altitude and distance records were set by aircraft using the Pegasus.
The Bristol Siddeley company reused the name many years later for the turbofan engine used in the Hawker Siddeley Harrier and which became known as the Rolls-Royce Pegasus when Rolls-Royce took over that company. Two Bristol Pegasus engines remain airworthy in 2010, powering Fairey Swordfish aircraft operated by the Royal Navy Historic Flight (became Navy Wings in March 2019); other examples are preserved and on public display in aviation museums.
Design and development
The Pegasus was designed by Sir Roy Fedden as the follow-on to the Bristol Aeroplane Company's very successful Bristol Jupiter, using lessons learned in development of the Mercury.
“Bristol Pegasus” enters the record as r-9 piston aircraft engine family. Crown Archives preserves that source wording while asking what Bristol, Pegasus and piston can confirm, complicate or overturn.
Why this record matters
“Bristol Pegasus” is worth following because a concise public description often conceals a longer documentary argument. Here, Bristol, Pegasus and piston provides the most credible route into that argument.
Vocabulary and entity names are the principal evidence signals here, because they determine the precision of every later search. The source revision retrieved here is dated Sep 12, 2026. The linked authority identifier is Q917964. None of the 0 selected statements returned an explicit reference. The first chronological checks are 2010 and 2019.
The absence of detail may reflect summary conventions rather than a lack of surviving documentation. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.
- Subject orientation
- Search vocabulary
- Locating named sources
The closest primary source, responsible institution and strongest cited specialist reference.
Three-step research path
- Establish the record: confirm the title “Bristol Pegasus”, its source revision and the description used here.
- Expand the search: follow Bristol Pegasus primary sources, Bristol Pegasus archive and Bristol research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Bristol Pegasus”?
- What terminology or title could unlock a more precise catalogue search?
- Which institution is responsible for the underlying evidence?
Search terms from this dossier
This entry incorporates text from “Bristol Pegasus” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.