# Lycoming GSO-580

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This article is about the 1959-era geared, eight-cylinder aircraft engine series. For the 1997 six-cylinder engine, see [Lycoming IO-580](/source/Lycoming_IO-580).

GSO-580 Type Piston aero-engine Manufacturer Lycoming Engines Major applications Beechcraft Model 34 Fairchild XNQ Manufactured 1948–1961

The **Lycoming GSO-580** is a family of eight-cylinder [horizontally opposed](/source/Flat_engine), [supercharged](/source/Supercharger), [carburetor](/source/Carburetor)-equipped aircraft engines for both airplanes and [helicopters](/source/Helicopters), manufactured by [Lycoming Engines](/source/Lycoming_Engines) in the late 1950s and early 1960s.[1][2]

The family includes the original GSO-580 [fixed-wing aircraft](/source/Fixed-wing_aircraft) engine series, as well as the later **SO-580** and **VSO-580** helicopter engines. There is no non-supercharged, non-geared version of the engine, which would have been designated O-580 and therefore the base model is the GSO-580.[1][2]

## Design and development

The GSO-580 family of engines covers a range from 375 hp (280 kW) to 400 hp (298 kW). All have a [displacement](/source/Engine_displacement) of 578 cubic inches (9.47 litres) and the cylinders have air-cooled [heads](/source/Cylinder_head). Compared to other horizontally opposed engines of similar displacement this family of engines produces high output power by supercharging and high maximum rpm, at the cost of higher weight.[1][2]

The GSO-580 series was [certified](/source/Type_certificate) under Type Certificate 256, while the SO-580 and VSO-580 series were certified under type certificate 285. Both were manufactured under Production Certificate No. 3.[1][2]

## Variants

**O-580-1**
- Military variant similar to the GSO-580-D[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*]

**GSO-580**
- Eight-cylinder, horizontally opposed, geared-drive, supercharged, 578 cubic inches (9.47 litres), 375 hp (280 kW) at 3300 rpm for take-off, 320 hp (239 kW) at 3000 rpm continuous, dry weight 619 lb (281 kg), Bendix PSH-9BDE carburetor. Minimum fuel grade 91/98 [avgas](/source/Avgas). Designation indicates *Geared, Supercharged, Opposed*.[1]

**GSO-580-B**
- Eight-cylinder, horizontally opposed, geared-drive, supercharged, 578 cubic inches (9.47 litres), 400 hp (298 kW) at 3300 rpm for take-off, 350 hp (261 kW) at 3000 rpm continuous, dry weight 624 lb (283 kg), Bendix PSH-9BDE carburetor. Minimum fuel grade 100/130 avgas. Designation indicates *Geared, Supercharged, Opposed*.[1]

**GSO-580-C**
- Eight-cylinder, horizontally opposed, geared-drive, supercharged, 578 cubic inches (9.47 litres), 375 hp (280 kW) at 3300 rpm for take-off, 320 hp (239 kW) at 3000 rpm continuous, dry weight 604 lb (274 kg), Bendix PS-9BDE carburetor. Minimum fuel grade 91/98 avgas. Designation indicates *Geared, Supercharged, Opposed*.[1]

**GSO-580-D**
- Eight-cylinder, horizontally opposed, geared-drive, supercharged, 578 cubic inches (9.47 litres), 400 hp (298 kW) at 3300 rpm for take-off, 350 hp (261 kW) at 3000 rpm continuous, dry weight 608 lb (276 kg), Bendix PS-9BDE carburetor. Minimum fuel grade 100/130 avgas. Designation indicates *Geared, Supercharged, Opposed*.[1]

**SO-580-A1A**
- Eight-cylinder, horizontally opposed, geared-drive, supercharged, 578 cubic inches (9.47 litres), 400 hp (298 kW) at 3300 rpm for take-off, 350 hp (261 kW) at 3000 rpm continuous, dry weight 596 lb (270 kg), Bendix PS-9BDE carburetor. Minimum fuel grade 100/130 avgas. Designation indicates *Supercharged, Opposed*. Designed for horizontal or up to 35 degrees nose-up helicopter installation.[2]

**SO-580-A1B**
- Eight-cylinder, horizontally opposed, geared-drive, supercharged, 578 cubic inches (9.47 litres), 400 hp (298 kW) at 3300 rpm for take-off, 350 hp (261 kW) at 3000 rpm continuous, dry weight 578 lb (262 kg), Bendix PS-9BDE carburetor. Minimum fuel grade 100/130 avgas. Designation indicates *Supercharged, Opposed*. Designed for horizontal or up to 35 degrees nose-up helicopter installation.[2]

**VSO-580-A1A**
- Eight-cylinder, horizontally opposed, geared-drive, supercharged, 578 cubic inches (9.47 litres), 400 hp (298 kW) at 3300 rpm for take-off, 350 hp (261 kW) at 3000 rpm continuous, dry weight 592 lb (269 kg), Bendix PS-9BDE carburetor. Minimum fuel grade 100/130 avgas. Designation indicates *Vertical-mounted, Supercharged, Opposed*. Designed for vertical helicopter installation.[2]

## Applications

**GSO-580**

- [Beechcraft Model 34](/source/Beechcraft_Model_34)

- [Cessna 308](/source/Cessna_308)[3]

- [Fairchild XNQ](/source/Fairchild_XNQ)

**SO-580**

- [Doman LZ-5](/source/Doman_LZ-5)[4]

## Specifications (VSO-580-A1A)

*Data from* FAA AIRCRAFT ENGINE SPECIFICATION E-285, Revision 2[2]

### General characteristics

- **Type:** 8-cylinder fuel-injected horizontally opposed, vertically mounted, helicopter engine

- **[Bore](/source/Bore_(engine)):** 4.875 in (123.8 mm)

- **[Stroke](/source/Stroke_(engine)):** 3.875 in (98.4 mm)

- **[Displacement](/source/Engine_displacement):** 578 cu in (9.47 L)

- **[Dry weight](/source/Dry_weight):** 592 lb (269 kg) dry

### Components

- **[Supercharger](/source/Supercharger):** 7.91:1 drive ratio

- **Fuel system:** Bendix PS9BDE carburetor

- **Fuel type:** 100/130 [avgas](/source/Avgas) minimum

- **Cooling system:** air-cooled

### Performance

- **Power output:** 400 hp (300 kW) at 3300 rpm

- **[Specific power](/source/Power_density):** 0.51 hp/in³ (33.3 kW/L)

- **[Compression ratio](/source/Compression_ratio):** 7.30:1

- **[Power-to-weight ratio](/source/Power-to-weight_ratio):** 0.68 hp/lb (1.12 kW/kg)

## See also

- [Lycoming IO-580](/source/Lycoming_IO-580)

**Related lists**

- [List of aircraft engines](/source/List_of_aircraft_engines)

## References

1. ^ [***a***](#cite_ref-E256_1-0) [***b***](#cite_ref-E256_1-1) [***c***](#cite_ref-E256_1-2) [***d***](#cite_ref-E256_1-3) [***e***](#cite_ref-E256_1-4) [***f***](#cite_ref-E256_1-5) [***g***](#cite_ref-E256_1-6) [***h***](#cite_ref-E256_1-7) [Federal Aviation Administration](/source/Federal_Aviation_Administration) (April 1959). ["AIRCRAFT ENGINE SPECIFICATION, Revision 6"](http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/72B3B8E50E7712F586256B1B00667681?OpenDocument&Highlight=580). Retrieved 2009-01-04.

1. ^ [***a***](#cite_ref-E285_2-0) [***b***](#cite_ref-E285_2-1) [***c***](#cite_ref-E285_2-2) [***d***](#cite_ref-E285_2-3) [***e***](#cite_ref-E285_2-4) [***f***](#cite_ref-E285_2-5) [***g***](#cite_ref-E285_2-6) [***h***](#cite_ref-E285_2-7) [Federal Aviation Administration](/source/Federal_Aviation_Administration) (March 1959). ["AIRCRAFT ENGINE SPECIFICATION, Revision 2"](http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/985CC61D95E1681A8525670E004F6395?OpenDocument&Highlight=580). Retrieved 2009-01-04.

1. **[^](#cite_ref-Cessnas_3-0)** Murphy, Daryl (2006). ["The Cessnas that got away"](https://web.archive.org/web/20090227001732/http://www.wingsoverkansas.com/features/article.asp?id=461). Archived from [the original](http://www.wingsoverkansas.com/features/article.asp?id=461) on 2009-02-27. Retrieved 2008-12-22.

1. **[^](#cite_ref-NEAM_4-0)** Collinge, Ken & Glidden S. Doman (2006). ["Doman Helicopters: Unsung Innovations, Part 1"](http://www.neam.org/articles/a_doman1.asp). Retrieved 2009-01-04.

v t e Lycoming aircraft engines Opposed piston engines O-145 O-233 IO-233 O-235 O-290 O-320 O-340 O-360 (O-360 variants) IO-390 O-435 O-480 O-540 TIO-541 GSO-580 IO-580 IO-720 O-1230 Radial engines and H engines R-680 XR-7755 XH-2470 Aircraft diesel engines DEL-120 Turbofans PLF1 ALF 502/YF102 LF 507 Turboprops/Turboshafts AGT1500 LTS101/LTP101 T53 T55 Aero-derivative marine gas turbines TF-40 Joint development Avco (Lycoming)/Pratt & Whitney: T800-APW (Turboshaft) See also AlliedSignal Aerospace/Honeywell Aerospace

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Adapted from the Wikipedia article [Lycoming GSO-580](https://en.wikipedia.org/wiki/Lycoming_GSO-580) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Lycoming_GSO-580?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.