New sailplane LAK-19
[LAK 19 Highlights which made this glider so special]
[Description] [Technical data] [Pictures] [Articles]
LAK 19 sn.1 during WGC in Leszno 2003, pilot Luka Znidarsic
Description of new LAK-19
(The construction of the LAK-19 is almost the same as the LAK-17A, except the flaps, of course)The LAK-19 is a new generation of Standard/18m class sailplane, designed according to JAR-22 category "U" specifications. EASA certified. It is a mid-wing gilder with T-tail, retractable main landing gear and is capable of carrying 180 l water ballast.
The sailplane is made of hybrid composite materials (kevlar, carbon, and glass fibre). The wing spar is made of modern carbon rods Graphlite SM315 and has a double T section. The weight of each wing panel is about 55 kg. The airbrakes are situated in 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 long flights. The one-piece canopy hinges forward. On the left side there is a sliding window with additional ventilation. The instrument panel lifts up together with the canopy.
The retractable landing gear has a 350xl35 tire and shock absorber. Disk wheel brake is actuated by airbrakes handle. 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 as well as aerotow take off. The wings incorporate fork-type spar roots joined with two pins.
The T-tail (fixed stabilizer with elevator) of the LAK-19 provides stable and responsive pitch characteristics. The elevator hooks up automatically during assembly. The glider is fitted with a fin ballast tank (capacity 7 liters) 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 emptied out through the holes at the bottom of the wings. The VHF antenna is mounted in the vertical fin.
Technical data LAK-19
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 | 480 kg | 480 kg |
| Min. wing loading | 31.5 kg/m2 | 30.1 kg/m2 |
| Max. wing loading | 53 kg/m2 | 49 kg/m2 |
| g limits without ballast | +7.5/-3.5 | +7.2/-3.6 |
| g limits with ballast | +5.3/-2.65 | +5.3/-2.65 |
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 | 69 km/h | 65km/h |
| Best L/D without ballast at 95km/h | 44 | 48 |
| Best L/D with ballast at 135 km/h | 45 | 49 |
| Min. sink rate | 0.54 m/s | 0.49 m/s |
Flight polar at different wing loadings and spans. Note that now max TO weight is 480kg not 453kg!