Schempp-Hirth Nimbus-2
{{Short description|German single-seat glider, 1971}}
{{Infobox aircraft
| name=Nimbus-2
| image=Glider - panoramio.jpg
| caption=Schempp-Hirth Nimbus-2
| type=Open-class sailplane
| national_origin=Germany
| manufacturer=Schempp-Hirth
| designer=Klaus Holighaus
| first_flight=April 1971
| introduction=
| retired=
| status=
| primary_user=
| number_built=243
| developed_from=
| variants=
}}
The Schempp-Hirth Nimbus-2 is an Open Class glider built by Schempp-Hirth during the 1970s. The Nimbus-2 first flew in April 1971 and a total of over 240 examples of all subtypes have been built until the beginning of the 1980s. It replaced the Schempp-Hirth Cirrus.
Design and development
Loosely based on the original Nimbus HS-3 prototype, the production version that eventually surfaced as the Nimbus-2 was a very different glider with many improvements over the problematic prototype. The wing was shortened to 20.3 metres and was built in four sections to make it easier to rig and transport. It received Schempp-Hirth air brakes fitted in the upper surfaces and a tail braking-parachute, plus camber-changing flaps. It had an all-flying T-tail similar to the Standard Cirrus as well as the general layout of its fuselage.
The Nimbus-2 was successful in competitions, twice winning the Open Class in World Gliding Championships: Göran Ax (Sweden) in 1972 and George Moffat (USA) in 1974. It was also popular with record-seekers. Bruce Lindsey Drake, David Napier Speight and Sholto Hamilton "Dick" Georgeson jointly set a World Goal and Free Distance record of 1,254 km in New Zealand in 1978, Doris Grove a feminine Out and Return record of 1,127 km in 1981, Yvonne Loader a feminine Height Gain record of 10212 m in 1988, and Joann Shaw a feminine Distance record of 951.43 km in 1990, all flying Nimbus-2. At its time several national and world records were held by Nimbus-2M's in the FAI motorglider category. In 1979 Klaus Holighaus, the glider's designer, completed the first 1,000 km triangle in Germany flying a Nimbus-2.
The Nimbus-2 was succeeded by the Schempp-Hirth Nimbus-3.
Variants
;Nimbus-2
:All-flying tailplane variant, serial numbers up to 85
;Nimbus-2B
:With a fixed incidence horizontal tail to improve pitch control behaviour
;Nimbus-2C
:Lighter variant with higher maximum certified flight mass, new trailing-edge combined airbrakes-flaps derived from the Glasflügel 303 Mosquito in place of the upper surface air brakes, and carbon-fibre wings and tailplane. Several other improvements took place during the production run without changes to the type designation.
;Nimbus-2CS
:Single example (serial number 192) with reduced fuselage weight, an increased span of 23.5 m, an enlarged rudder and several other modifications.
;Nimbus-2M
:Self-launching version with a retractable engine. It is based on the Nimbus-2 (not 2b) but the wing is 15 cm further aft on the fuselage to make up for the C of G shift induced by the weight of the engine (7 built)
;Skopil Nimbus II-S
:Motorglider conversion done by Arnold Skopil of Aberdeen, Washington, United States using a Nelson H-63 engine of {{convert|45|hp|kW|0|abbr=on}}. One converted.Said, Bob: 1983 Sailplane Directory, Soaring Magazine, page 131. Soaring Society of America, November 1983. USPS 499-920
Specifications (Nimbus 2)
{{Aircraft specs
|ref=Jane's all the World's Aircraft 1976–77 {{cite book |title=Jane's all the World's Aircraft 1976–77 |editor1-last=Taylor |editor1-first=John W.R. |edition=67th |year=1976 |publisher=Jane's Yearbooks |location=London |isbn=0-3540-0538-3 |page=566}}
|prime units?=met
|crew=1
|capacity={{cvt|160|kg}} water ballast
|length m=7.33
|length ft=
|length in=
|length note=
|span m=20.3
|span ft=
|span in=
|span note=
|height m=1.45
|height ft=
|height in=
|height note=
|wing area sqm=14.4
|wing area sqft=
|wing area note=
|aspect ratio=28.62
|airfoil=root: Wortmann FX 67-K-170/17 (17%); tip: Wortmann FX 67-K-150/17 (15%){{cite web |last1=Lednicer |first1=David |title=The Incomplete Guide to Airfoil Usage |url=https://m-selig.ae.illinois.edu/ads/aircraft.html |website=m-selig.ae.illinois.edu |accessdate=16 April 2019}}
|empty weight kg=350
|empty weight lb=
|empty weight note=
|gross weight kg=470
|gross weight lb=
|gross weight note=maximum without water ballast
|max takeoff weight kg=580
|max takeoff weight lb=
|max takeoff weight note=with water ballast
|more general=
|stall speed kmh=64
|stall speed mph=
|stall speed kts=34
|stall speed note=at W/S 32 kg/m2
|never exceed speed kmh=270
|never exceed speed mph=168
|never exceed speed kts=146
|never exceed speed note=
- Max aerotow speed: {{cvt|160|km/h|mph kn}}
- Max winch launch speed: {{cvt|120|km/h|mph kn}}
|g limits=+10.5
|roll rate=
|glide ratio=49 at {{cvt|105|km/h|mph kn}}
|sink rate ms=0.53
|sink rate ftmin=
|sink rate note=at {{cvt|90|km/h|mph kn}}
|lift to drag=
|wing loading kg/m2=40
|wing loading lb/sqft=
|wing loading note=with water ballast
:::{{cvt|32.6|kg/m2}} without water ballast
|more performance=
}}
See also
{{aircontent
|see also=
|related=
|similar aircraft=
|lists=
}}
References
{{reflist}}
Further reading
- Thomas F, Fundamentals of Sailplane Design, College Park Press, 1999
- Simons M, Segelflugzeuge 1965-2000, Eqip, 2004
External links
{{Commons category|Schempp-Hirth Nimbus 2}}
- [http://www.sailplanedirectory.com/ Sailplane Directory]
- [http://www.rcawsey.co.uk/nimbus2.htm Production list]
- [http://www.schempp-hirth.com/ Schempp-Hirth homepage]
{{Schempp-Hirth}}