Lycoming O-145
family of small, low-horsepower, four-cylinder, air-cooled engines
The Lycoming O-145 is a family of small, low-horsepower, four-cylinder, air-cooled engines. It was Lycoming Engines' first horizontally opposed aircraft engine and was produced from 1938 until the late 1940s. The family includes the reduction-geared GO-145. The O-145 received its Approved Type Certificate on 13 Jun 1938.
Design and development
The O-145 was produced in three major versions, the O-145-A rated at 55 hp (41 kW), the -B rated at 65 hp (48 kW), and -C rated at 75 hp (56 kW). The "B" model was the major production model, with the "A" and "C" produced in much smaller quantities.
All models of the series had the same bore, stroke, and displacement, additional horsepower being generated by increasing compression ratio and maximum rpm. All use a Stromberg NA-S2 or NA-S2A or Marvel MA-2 or MA-2-A carburetor. The dual ignition versions use two Scintilla SF-4L, SN4LN-20 or -21, Superior SMA-4 or Edison-Splitdorf RMA-4 magnetos.
The original O-145-A produced 55 hp (41 kW) at 2300 rpm, weighed 165.5 lb (75 kg), and featured single ignition.
“Lycoming O-145” enters the record as family of small, low-horsepower, four-cylinder, air-cooled engines. Crown Archives preserves that source wording while asking what Lycoming, O-145 and family can confirm, complicate or overturn.
Why this record matters
“Lycoming O-145” is worth following because a concise public description often conceals a longer documentary argument. Here, Lycoming, O-145 and family provides the most credible route into that argument.
Named sources, stable identifiers and responsible institutions provide the strongest route from overview to verifiable evidence. The source revision retrieved here is dated Jul 26, 2026. The linked authority identifier is Q6707348. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1938.
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 “Lycoming O-145”, its source revision and the description used here.
- Expand the search: follow Lycoming O-145 primary sources, Lycoming O-145 archive and Lycoming 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 “Lycoming O-145”?
- Which institution is responsible for the underlying evidence?
- What terminology or title could unlock a more precise catalogue search?
Search terms from this dossier
This entry incorporates text from “Lycoming O-145” 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.