Rolladen Schneider LS4
Vne: 270 km/h
In very turbulent air: 180 km/h
In winch launch: 130 km/h
In tow-plane launch: 180 km/h
Manoeuvring speeds: 85 – 180 km/h (green area on ASI)
Performance at minimum wing loading (about 33 kg/m2):
Top speeds: as stated above.
Stall speed: 65-70 km/h
Least possible sink rate: 0.6 m/s @ 80 km/h
Best gliding ratio: 42:1 @ 95 km/h
Recommended approach speed: 90 km/h
Performance at maximum wing loading (about 45 kg/m2):
Top speeds: as stated above.
Stall speed: 75-80 km/h
Least possible sink rate: 0.75 m/s @ 95 km/h
Best gliding ratio: 42:1 @ 120 km/h
Recommended approach speed: 100 km/h
Maximum permitted G-force: +5.3 and -2.65
Approved aerobatics: None
Water ballast: 2x 70L. (140 kg)
The LS4 is the glider that I have flown most. Compared to other gliders that I have flown, the LS4 is very light and responsive on the controls. It also climbs very easily, even in weak thermals. Apart from this, having a gliding ratio of 42:1, it can really glide a long way before you start feeling the need to ‘refuel.’
As you can see from the data above, the aircraft is quite well performing. The aircraft is also very forgiving. You can really provoke it without it ‘biting’ you back. However, it can spin. I have experienced that if you exaggerate a stall and use full deflection of the rudder and up elevator while on the edge of stall, the aircraft can ‘drop a wing’ and begin to spin. This is also depending on the position of the centre of gravity. If the CG is in a forward position (heavy cockpit load), the aircraft is less likely to spin.
One thing that I like about the LS4, is it’s ability to maintain attitude. Sometimes, after finding a thermal and getting centred in it, you can release the controls and the aircraft will maintain attitude and climb nicely with very small corrections. That’s the time to get your lunch pack out and start eating.
I have flown this aircraft in different configurations. Without any ballast, the aircraft is very light and has a very high roll-rate. However, flying fast in this configuration will cost quite a lot of altitude.
With 50L of water ballast, the aircraft is basically the same, just slightly better at gliding in head winds.
With 100L of ballast, you start feeling the difference. The aircraft becomes relatively heavy on the controls, however it glides really nicely at high speeds.
At 140L of ballast the aircraft is rather heavy, and the thermals have to be quite strong, or else it cannot pay off to have the ballast. However, when gliding straight and level, the aircraft becomes a dream to fly. You simply push the stick forward and see the speed increasing without too much altitude loss. When flying in this configuration, I felt that I needed over 120 km/h at the tow-plane launch for the aircraft to behave properly. You can clearly feel the high angle of attack when flying at low speeds with this rather high wing-loading.
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