|IS-29, IS-31, and IS-33|
|First flight||April 1970|
The ICA IS-29 was a sailplane built in Romania in the 1970s. The prefix IS comes from Iosif Silimon, the Romanian IAR (Industria Aeronautică Română) aeronautical engineer who designed it. The 15-metre (49 feet) single place sister of the IS-28 series, the IS-29D2 single-seater has retractable gear, camber-changing flaps and Hütter type airbrakes on the upper wing surface only. The T-tail has a fixed stabilizer and elevator. The –29D model is of all metal construction while the earlier –29B has wooden wings. Developments include 19 metre (62 ft) -29E2 and 20 m (66 ft) -29E3 versions and a flapless, fixed gear 16.5-metre (54 feet) ‘club’ model -29G.
The aircraft demands reasonable training skills from the pilot, being known for its capability of entering a stall quite quickly, can lead to a spin. This is not uncommon in many gliders. The 29d's supposed deep stall was long debunked by exhaustive test flying in Australia and was well documented in various issue of "Australian Gliding" , the official GFA magazine at the time, in the 1970s. Recovery from stall/spin situations are similar to for example, the SZD Puchacz. Its general handling is excellent and is highly aerobatic in the right hands, with high positive and negative strength factors. The pilot should be always aware of the stalling speed during flight and especially at the proximity with the ground (at take offs and landings) where the recovery from this scenario is impossible to perform.
- IS-29B - wooden wings of 15-metre span
- IS-29D2 Club - Club-class version of IS-29D2
- IS-29E - open class version with ballast tanks
- IS-29E2 - version with 19-metre wings
- IS-29E3 - version with 20-metre wings
- IS-29EM - motorglider version
- IS-29G - Club-class version with 16.5-metre wings
- IS-31 - IS-29 with 20-metre wings and linked flaps and ailerons
- IS-33 - IS-29 with tanks for 150 kg (300 lb) of water ballast
- Crew: 1
- Length: 7.3 m (23 ft 11 in)
- Wingspan: 15 m (49 ft 3 in)
- Height: 1.68 m (5 ft 6 in)
- Wing area: 10.4 m2 (112 sq ft)
- Aspect ratio: 21.6
- Airfoil: root:Wortmann FX 61-163, tip:Wortmann FX 60-126/1
- Empty weight: 240 kg (529 lb)
- Max takeoff weight: 360 kg (794 lb)
- Stall speed: 65 km/h (40 mph; 35 kn) flaps down
- Never exceed speed: 225 km/h (140 mph; 121 kn) in smooth air
- Max rough air speed: 172 km/h (93 kn; 107 mph)
- Max aero-tow speed: 140 km/h (76 kn; 87 mph)
- Max winch-launch speed: 130 km/h (70 kn; 81 mph)
- g limits: +5.2 -2.65
- Maximum glide ratio: 37
- Best glide speed: 93 km/h (50 kn; 58 mph)
- Rate of sink: 0.65 m/s (128 ft/min)
- Minimum sink speed: 78 km/h (42 kn; 48 mph)
- Wing loading: 34.62 kg/m2 (7.09 lb/sq ft)
- Soaring Society of America
- Taylor, Michael J. H. (1989). Jane's Encyclopedia of Aviation. London: Studio Editions. p. 528.
- Hardy, Michael (1982). Gliders and Sailplanes of the World. Shepperton: Ian Allan. pp. 54–55.
- Coates, Andrew (1978). Jane's World Sailplanes and Motor Gliders. London: MacDonald and Jane's. p. 124.
- Simpson, R. W. (1995). Airlife's General Aviation. Shrewsbury: Airlife Publishing. p. 342.
- Jane's All the World's Aircraft 1977-78. London: Jane's Yearbooks. p. 608.