Earthstar Thunder Gull

The Earthstar Thunder Gull is a family of cantilever high-wing, tricycle gear ultralight aircraft, manufactured by Earthstar Aircraft of Santa Margarita, California as a kit for amateur construction or as a completed aircraft.[1][2][3][4][5][6][7][8][9][10]

Earthstar Thunder Gull
Earthstar Thunder Gull Odyssey
Role Ultralight aircraft
National origin United States
Manufacturer Earthstar Aircraft
Designer Mark Beierle
First flight March 1987 (Thunder Gull)
Introduction 1987 (Thunder Gull)
Status In production (2012)
Gull 2000 on skis
Thunder Gull Odyssey
Thunder Gull Odyssey showing the unusual staggered side-by-side seating arrangement

Design and development

Designer Mark Beierle's original goals were an "airplane with the feel of a hang glider, the agility and visibility of a helicopter, the effortless smooth flight of a sailplane, and the utility and economy of a general aviation aircraft--all in the hopes of getting close to the feel and freedom of a bird." When queried by interviewer Don Downie if that was too much to ask, Beierle replied, "You bet! But it didn't stop me from trying."[11]

The Thunder Gull was introduced in 1987 as a development of the earlier Laughing Gull. The aircraft was quite revolutionary when it was introduced due to its high performance and particularly high cruise speed of 55 mph (89 km/h) on just 28 hp (21 kW).[1]

The aircraft is constructed from aluminum tubing and sheet parts and covered in aircraft fabric. The aircraft can meet the requirements of the US FAR 103 Ultralight Vehicles category, including its maximum empty weight limitation of 254 lb (115 kg) when it is equipped with a lightweight engine.[1][12]

The aircraft has a very small wing for the US ultralight category with a wing area of only 95 sq ft (8.8 m2) and a wingspan of 17.6 ft (5.4 m). The wing is equipped with flaps that give it a stall speed of 25 mph (40 km/h). The small wing gives the aircraft a high cruise speed and better resistance to turbulence than a lighter-loaded wing. The one-piece wing is quickly removable for storage or transport.[1][3]

Reported construction time of the kit is 150 hours.[1]

Operational history

The prototype Laughing Gull was flown coast-to-coast across the USA seven times with 100 lb (45 kg) of baggage and a 180 lb (82 kg) pilot.[2]

Variants

Laughing Gull
Original model introduced in 1976. First models had wire bracing and later strut-bracing before development of the cantilever wing. Production completed.[2][11]
Thunder Gull
Single-seat, high-wing ultralight aircraft with a cantilever 17.6 ft (5.4 m) wing. The name was changed from Laughing Gull for marketing purposes. Production completed.[1][11]
Thunder Gull J
Improved model with 20 ft (6.1 m) wingspan. Standard engine is the 28 hp (21 kW) Rotax 277 and the acceptable power range is 28 to 53 hp (21 to 40 kW). First flight was March 1987 and it was available as a kit or ready-to-fly. Production completed.[2][3][4][5]
Thunder Gull JT2
Two seats in tandem model with dual controls and a 24 ft (7.3 m) wingspan. Standard engine is the 50 hp (37 kW) Rotax 503 and the acceptable power range is 40 to 80 hp (30 to 60 kW). The 64 hp (48 kW) Rotax 582 and 75 hp (56 kW) Rotax 618 two-stroke engines were optional. It was available as a kit or ready-to-fly and production is completed. First flight was June 1989.[1][2][3][4][5]
Thunder Gull Odyssey
Two seats in an unusual staggered side-by-side configuration with dual controls in the form of a shared center stick and a 26 ft (7.9 m) wingspan. The staggered seating was used to provide most of the benefits of side-by-side seating without the associated drag penalty. The seat stagger is sufficient to provide pilot shoulder clearance. Standard engine is the 50 hp (37 kW) Rotax 503 and the acceptable power range is 40 to 80 hp (30 to 60 kW). The 60 hp (45 kW) HKS 700E has also been installed. It first flew in April 1995 and was introduced at Sun 'n Fun in 1995. It is available as a kit or ready-to-fly. Fifteen were reported completed by December 2011 and still in production in 2012.[1][2][3][4][5][6][7][8][9][10][11][13] An electric aircraft version has been flown.[12]
Soaring Gull
Motorglider version with 28 ft (8.5 m) wingspan and 16:1 glide ratio. Standard engine was the 28 hp (21 kW) Rotax 277 and then later the 28 hp (21 kW) Hirth F-33. The acceptable power range is 28 to 53 hp (21 to 40 kW). First flew in November 1993. Ten reported as completed by December 2011 and still in production in 2012.[1][2][3][4][5][7][8][9][10][13]
Gull 2000
Updated version with 20 ft (6.1 m) wingspan, wider cockpit enclosure built from fiberglass. Standard engine was the Zanzottera MZ 34 of 27 hp (20 kW) and then later the 28 hp (21 kW) Hirth F-33. The acceptable power range is 27 to 60 hp (20 to 45 kW). Fifteen reported as completed by December 2011 and still in production in 2012.[1][4][5][6][7][8][9][10][13]
eGull 2000
Electric powered variant
eGull 2000 in flight
eGull 2000, an electric-powered variant

Specifications (Thunder Gull)

Data from Cliche[1]

General characteristics

  • Crew: one
  • Length: 17 ft 3 in (5.26 m)
  • Wingspan: 17 ft 7 in (5.36 m)
  • Wing area: 95 sq ft (8.8 m2)
  • Empty weight: 252 lb (114 kg)
  • Gross weight: 550 lb (249 kg)
  • Fuel capacity: 5 US Gallons (19 Litres)
  • Powerplant: 1 × Rotax 277 , 28 hp (21 kW)
  • Propellers: 2-bladed wooden

Performance

  • Maximum speed: 63 mph (101 km/h, 55 kn)
  • Cruise speed: 55 mph (89 km/h, 48 kn)
  • Stall speed: 25 mph (40 km/h, 22 kn) flaps down
  • Range: 165 mi (266 km, 143 nmi)
  • Service ceiling: 14,000 ft (4,300 m)
  • Rate of climb: 700 ft/min (3.6 m/s)

See also

Aircraft of comparable role, configuration, and era

References

  1. Cliche, Andre: Ultralight Aircraft Shopper's Guide 8th Edition, pages B-61 & B-107. Cybair Limited Publishing, 2001. ISBN 0-9680628-1-4
  2. Purdy, Don: AeroCrafter - Homebuilt Aircraft Sourcebook, pages 148 and 307. BAI Communications. ISBN 0-9636409-4-1
  3. Downey, Julia: 1999 Kit Aircraft Directory, Kitplanes, Volume 15, Number 12, December 1998, page 44. Primedia Publications. ISSN 0891-1851
  4. Downey, Julia: 2001 Kit Aircraft Directory, Kitplanes, Volume 17, Number 12, December 2000, page 44. Kitplanes Acquisition Company. ISSN 0891-1851
  5. Downey, Julia: 2002 Kit Aircraft Directory, Kitplanes, Volume 18, Number 12, December 2001, pages 33-34. Kitplanes Acquisition Company. ISSN 0891-1851
  6. Newby-Gonzalez, Tori: 2004 Kit Aircraft Directory, Kitplanes, Volume 20, Number 12, December 2003, page 65. Belvoir Publications. ISSN 0891-1851
  7. Downey, Julia: 2005 Kit Aircraft Directory, Kitplanes, Volume 21, Number 12, December 2004, page 55. Belvoir Publications. ISSN 0891-1851
  8. Downey, Julia: 2008 Kit Aircraft Directory, Kitplanes, Volume 24, Number 12, December 2007, page 49. Primedia Publications. ISSN 0891-1851
  9. Earthstar Aircraft (n.d.). "Models". Retrieved 25 January 2011.
  10. Vandermeullen, Richard: 2012 Kit Aircraft Buyer's Guide, Kitplanes, Volume 28, Number 12, December 2011, page 51. Belvoir Publications. ISSN 0891-1851
  11. Downie, Don (June 2000). "The Gull Report.(flying building Ultralight aircraft personal narratives)". KitPlanes. Retrieved 26 January 2011.
  12. Tacke, Willi; Marino Boric; et al: World Directory of Light Aviation 2015-16, page 44. Flying Pages Europe SARL, 2015. ISSN 1368-485X
  13. Bayerl, Robby; Martin Berkemeier; et al: World Directory of Leisure Aviation 2011-12, page 43. WDLA UK, Lancaster UK, 2011. ISSN 1368-485X
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