Handy Info for ASK21

Speed brakes use keys 3 & 4. (Three settings: Handle full forward is off, handle full back is full braking!)

Glide Ratio max 1:32

Need 155 k/h for loop

Spin recover: rudder to stop turning, pause almost half rotation , then stick medium forward (not dive) to get airspeed.

Dashboard in x-plane glider ASK21: "winter" is variometer aka rate of climb & descent indicator "RCDI" (see https://en.wikipedia.org/wiki/Variometer )

FAA info re gliders including “low-tow” and “high-tow” position relative to tow-plane: https://www.faa.gov/regulations_policies/handbooks_manuals/aircraft/glider_handbook/

“Unique to the gliders is an instrument called the total energy variometer. If it is beeping, then the aircraft is in a nice updraft from the air following the terrain. Circling in that area will let the glider ride the climbing air to altitude! When the variometer is emitting a steady tone, the craft is in descending air—the glider has been blown to the wrong side of the mountain, and a crash will follow soon if the user does not find a way out of that area!”

• (Some? All? Just in mobile?) X-Plane gliders have an ADF automatic direction finder that always points toward the airport.

www.winter-instruments.de/stauscheiben-variometer----vanetype-vario

says "Nowadays, the MacCready type ring is an indispensable aid in cross country flying. The ring is rotatable and is marked with speeds and a white triangle. The chief use of MacCready ring is to achieve the highest possible cruising speed (average cross country flying speed) on thermal cross country flights. This involves setting the white arrow to the anticipated rate of climb for the next upcurrent. Optimum flight performance is assured when the airspeed indicated by the airspeed indicator corresponds to the preselected flying speed to which the MacCready ring has been set.

"The MacCready ring allows gliding distance and final approach to be optimised..."

Highlights from the POH (Pilots Operating Handbook)

Schliecher ASK-21 glider

Overall stats from http://soargbsc.com/members/manuals/ASK_21_Pilot_notes.pdf

ASK-21 has glide ratio = 34 to 1, and 128 fpm sink rate @ 42kts.

Nose-wheel must not touch ground during takeoff and landing or else risk pilot-induced oscillation (PIO).

Max crosswind component = 8kt = 9mph = 15km/h.

Take-off:

Keep the towplane just above your horizon. Fix slack in rope by yaw away from rope or apply 1/2 airbrakes.

Stall recovery: neutral stick for pitch: too far forward can flip the glider!

Landing: "55 & 5" (airspeed <= 55kts, sink <= 5kts down). Full airbrakes activates wheel brakes, so don't land with full airbrakes!! Land on main wheel and tailwheel, NOT nose wheel!

Instruments:

"Winter" vario is mechanical (no electricity required)

Lxnav S-3 is electric w/ audio.

G-meter has yellow warning bars at both top & bottom.

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From ASK-21 glider poh (which model? 1983)

Vs0 (stall speed with airbrakes retracted) = 35kts = 40mph = 65kmh

Vs1 (stall speed with airbrakes extended) = 37kts = 42mph = 68km/h

Vr = 40kts = 47mph = 75km/h

Green arc normal range is 43--97kts (50--112mph, 80--180km/h)

Yellow triangle (most favorable approach speed) = 49kts = 56mph = 90kmh.

[Slips to landing are allowed but notice that airspeed indicator shows zero! Hold nose up to horizon.]

Yellow arc caution range is 92--151kts (112--174mph, 180--280km/h)

Most favorable winch-tow speed is 50-60kts = 56-69mph = 90-110kh/h

Max winch tow speed = 81kts = 93mph = 150km/h

Most favorable aero-tow speed is 50-75kts = 56-87mph = 90-140km/h

Max aero tow speed = 97kts = 112mph = 180km/h

Vm (max maneuvering speed (full deflection)) = 97kts = 112mph = 180km/h

Vne (max permissible speed, rough air) = 108kts = 124mph = 200kmh

VLe (max airspeed with airbrakes) = 151kts = 174mph = 280km/h

Vne (max permissible speed, calm air) = 151kts = 174mph = 280km/h

Note: because ias is less that tas in thin air at altitude, Vne declines at altitude

Vne (5000' = 151kts = 174 mph; 10,000' = 144kts = 165mph; 15,000' = 132kts = 152mph; 20,000' = 121kts = 139mph)

Note: ias reads approx 22kts (40km/h) low when craft is inverted

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Weight & Balance:

Max back-seat and max front-seat payload = 242lb (110kg) each.

Solo flights must be conducted from front seat, and must compensate with nose ballast if pilot & parachute < 154 lbs (70kg).

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Aerobatics allowed except no abrupt maneuvers, no outside loop ("forward"), and no tail-slide.