Schempp-Hirth Mini-Nimbus
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| Type designation | Mini Nimbus |
| Competition class | 15 Metre class |
| Number built | 159 |
| Crew | 1 |
| Length | 6.4 m |
| Height | 1.31 m |
| Wingspan | 15 m |
| Wing area | 9.85 m² |
| Aspect ratio | 23 |
| Wing profile | Wortmann FX |
| Empty mass | 250 kg |
| Water ballast | 125 kg |
| Maximum mass | 450 kg |
| Wing loading | 32 - 45 kg/m² |
| Maximum speed | 250 km/h |
| Rough air speed | 200 km/h |
| Minimum sink rate | 0.53 m/s |
| Best glide ratio | 41 |
The Schempp-Hirth Mini Nimbus HS-7/B/C is a 15 metre-Class glider built by Schempp-Hirth GmbH.
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[edit] Design and development
Klaus Holighaus was managing two glider manufacturers: Schempp-Hirth and Glasflügel. In designing the glider he therefore used the wings from the Glasflügel 303 Mosquito. It first flew on 18 September 1976. The name "Mini Nimbus" was adopted to distinguish it from longer wingspan Nimbus models.
Based on the Standard Cirrus the original design (HS-7) had an all moving tailplane and fibre glass wing spars (models HS-7 and B), but a conventional tail was added for the B model, carbon-fibre wing spars were used for the C version. The conventional horizontal stabiliser/elevator configuration was less sensitive to inputs by the pilot making it easier to fly without constantly making small adjustments to the pitch attitude. This was due to the much larger control surface of the former compared to the later configuration.
A tailplane anti-balance tab was a required modification for certification in the United Kingdom after flight testing by Derek Piggott on behalf of the British Gliding Association revealed very low stick forces and marginal pitch stability of the HS-7 version.
The addition of carbon-fibre spars significantly lightened the Mini Nimbus improving its climbing performance and increasing water ballast capacity while making assembly and disassembly much easier. The Mini Nimbus range all feature self-connecting controls for added safety and ease of rigging.
The trim lever is connected to the flap operating rod and needs to be set only once per flight; thereafter changes in flap setting (-7 to +10 degrees) automatically provides trim compensation.
[edit] Performance
The Mini-Nimbus glide ratio was somewhat less competitive than its primary rival in sailplane race competitions, the Alexander Schleicher ASW 20. However its superior climbing performance (altitude gained over time while climbing in lifting air) over its rivals made it the choice of some successful international soaring competition pilots in the late 1970s.
A unique capability of the Mini Nimbus is its powerful integrated air brake/flap system which gives the aircraft a superior short field and steep landing approach capability. This is a significant safety enhancing capability especially during recreational or competitive cross-country flights where the risk of damage from landing in small rural cultivated fields or pastures is considerable.
[edit] Production
159 Mini-Nimbuses were built, many of which remain in use today and are sought out by pilots wishing to get the best competitive performance possible for the least cost.
[edit] Competition use
It was the favoured aircraft of former American world champion soaring pilot George Moffat in his attempt in the late 1970s to win two USA soaring championships where he proved that the skill of the pilot can overcome performance differences between competing aircraft. George Moffat won the 1977 European Gliding Championships flying a Mini Nimbus. The Mini Nimbus remains a formidable competitor in the Sports Class of sailplane racing where handicaps are allowed in scoring.
[edit] References
- Hardy, Michael. Gliders and sailplanes of the World. London: Ian Allen, 1982. ISBN 0-7110-1152-4.
[edit] External links
- Mini-Nimbus Owners Group
- British Gliding Association data sheet
- Manufacturers type page - German language
- Mini Nimbus Yahoo group
- Flight test evaluation - Soaring magazine, December 1977
- Mini Nimbus production list
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