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Description of new LAK-17A
The LAK-17A is a new generation of FAI 15m and 18m class sailplane designed according to JAR-22 category "U" specifications. It is a midwing glider with flaps, T-tail, retractable main landing gear and 180ltr water ballast. It is also EASA certified.
The sailplane is made of hybrid composite materials (kevlar, carbon, glass fibers). The wing spar is made of modern carbon rods GRAPHLITE SM315 and has double T section. The weight of each wing panel is about 55 kg. The airbrakes are situated on upper surfaces only. The wing airfoil is LAP 92-130/15 and it passes into the LAP 92-150/15 in the tip.
The cockpit is of monocoque construction. The manually contoured seat pan and an adjustable seat back together with optimally arranged control elements offer notable comfort on the long flights. The one piece Plexiglas (MECAPLEX, Switzerland) canopy hinges forward. On the left side there is a sliding window with additional ventilation. The instrument panel folds up together with canopy.
The retractable landing gear has 350x15 tyre. The mechanical main wheel brake is actuated via the handle on the stick. The rudder pedals are adjustable in flight. All controls, including the water ballast system, hook up automatically. The tow release is mounted near the main landing gear and permits winch powered take off. Wings incorporate fork-type spar tips, joined with two pins.
The T-tail (fixed stabilizer with elevator) of the LAK-17A provides stable and responsive pitch characteristics. The elevator hooks up automatically during assembly. The glider is fitted with a fin ballast tank (capacity 7 ltr.) in order to compensate the nose-heavy moment created by the high ballast loads in the wing tanks. The water ballast is filled in and poured out through the holes at the bottom of the wings. VHF-antenna is mounted in the vertical fin.
According to the customer’s order the glider could be supplied with 15m - 18m wing span version. For both configurations winglets are available.
Technical data LAK-17A
Dimensions, weights and loading
| Wing span | 15 m | 18 m |
| Wing area | 9.06 m2 | 9.8 m2 |
| Fuselage length | 6.53 m | 6.53 m |
| Height | 1.29 m | 1.29 m |
| Wing aspect ratio | 24.83 | 33 .06 |
| Empty weight approx. | 235 kg | 240 kg |
| Max. gross weight | 500 kg | 500 kg |
| Min. wing loading | 33.8 kg/m2 | 31.6 kg/m2 |
| Max. wing loading | 55 kg/m2 | 51 kg/m2 |
| g limits without ballast | -3.7/+7.5 | -3.6/+7.2 |
| g limits with ballast | -2.65/+5.3 | -2.65/+5.3 |
Speeds and performance
| Max. speed in calm air | 275 km/h | 275 km/h |
| Max. speed in rough air | 215 km/h | 215 km/h |
| Staling speed for straight and level flight, without water ballast, 15m span (depends on flap settings) | L=69, +2=69, +1=72, 0=75,-1=76 km/h | |
| Best L/D without ballast at 95km/h | 46 | 49 |
| Best L/D with ballast at 115 km/h | 47 | 50 |
| Min. sink rate | 0.54 m/s | 0.49 m/s |
