Grob G102 Astir
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|Astir CS in flight|
|First flight||December 1974|
The G102 Astir is a single seat glassfibre Standard Class sailplane, designed by Burkhart Grob and built by Grob Aircraft. It was the first Grob-designed sailplane, with the first flight in December 1974. Grob had previously built the Schempp-Hirth Standard Cirrus under licence.
Design and development
The Astir CS [Club Standard] is of composite (fiberglass/resin) construction, has a large wing area, a T-tail and water ballast tanks in its wings. The large wing area gives good low-speed handling characteristics but its high-speed performance is inferior to other Standard-class gliders. In early versions some of the fuselage frame was wood, but this was replaced with a light alloy casting which sometimes cracks after heavy landings. The tail dolly is unusual by being plugged into a vertical hole.
A slightly improved standard-class version, the CS 77, was introduced in 1977. It has a different rudder profile and a slimmer fuselage similar to that of the Speed Astir. The Standard II and Standard III versions followed in the early 1980s, reverting to the higher-profile fuselage and with a reduced empty weight and an increased payload.
The Astir CS Jeans was similar to the CS 77, but had a fixed mainwheel and a tailskid. Its cockpit was fitted in blue denim. Later versions were the Club II and the Club III which also had fixed gear, but the Club III had a tailwheel.
The numbers built of each type were: 536 CS, 244 CS77, 248 CS Jeans, 61 Club/Standard Astir II and 152 Club/Standard Astir III. A flapped version called the G104 Speed Astir was also produced.
One Astir (now residing at the Steven F. Udvar-Hazy Center), flown by Robert Harris, broke the world absolute altitude record at 49,009 ft (14,938 m) on 17 February 1986. This record lasted until 2006.
- Astir CS
- The original production version of the Astir, produced up to 1977 (CS = Club Standard)
- Astir CS77
- Production aircraft from 1977, with revised fuselage profile and other modifications
- Speed Astir
- The Astir with a flapped wing to comply with the FAI 15m Flapped Class, for gliding competitions
- Astir CS Jeans
- Astir aircraft with faired fixed undercarriage, to comply with the Club Class for gliding competitions and to provide "glass-ship" experience at lower cost.
- G102 Astir
- Designation introduced by Grob for the Astir series in the 1980s, with each successive improvement given the suffix I,II or III etc.
- G104 Speed Astir
- The Speed Astir re-designated
Specifications (Standard Astir III)
Data from Grob G102 manual
- Crew: 1
- Length: 6.75 m (22 ft 2 in)
- Wingspan: 15.0 m (49 ft 3 in)
- Height: 1.26 m (4 ft 2 in)
- Wing area: 12.4 m2 (133 sq ft)
- Aspect ratio: 18.2
- Empty weight: 250 kg (551 lb) approximately
- Gross weight: 450 kg (992 lb) with water ballast; without ballast 350 kg (770 lb)
- Maximum speed: 170 km/h (106 mph; 92 kn) manouevring and airtow
- Stall speed: 59 km/h (37 mph; 32 kn) without airbrakes
- Never exceed speed: 250 km/h (155 mph; 135 kn)
- Maximum glide ratio: Best 38, at 105 km/h (64 mph, 56 kn) and 0.77 m/s (152 ft/m)
- Rate of sink: 0.62 m/s (122 ft/min) minimum, at 76 km/hr (47 mph, 42 kn) and glide ratio 34
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