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Handbook for Sailplane
Schleicher KA6CR
A/ Main Data
B/ Minimum Equipment
C/ Adjusting Data
D/ Rigging & Derigging
E/ Flying Operation
F/ Maintenance
G/ Centre of Gravity
Enclosures: -
1/ Outline Drawing
2/ Drawing with Weighing Instructions
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A/ Main Data:
Weights: Empty Weight - 400 lbs
Highest Permissible disposable
Load - 265 lbs
Highest Permissible all-up
Weight - 660 lbs
Highest Permissible weight of non-lifting
parts - 420 lbs
Permission for:
Bungee launch Yes
Auto & Winch-tow Until 55 knots
Aero Tow Until 75 knots
Max speed in calm air 110 knots
Max speed in rough air 75 knots
Primary training No
Stalls & Spinning Yes
Stress Category 2 as per BVS
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B/ Minimum Equipment:
Safety belt and should harness.
Airspeed indicator ranging from 30 – 110 knots.
Altimeter, back cushion with rigid filling 4 inches thick (when
compressed).
Trimming plane.
Data Plate.
C/ Adjusting Data:
The adjusting and washout angles as well as the deflection of the
control surfaces are shown in the outline drawing.
During repairs it is important that the tolerances are being
adhered to.
By the particular kinematic of the control mechanism the aileron
deflection will be influenced by the elevator. With normal and
pushed control stick the ailerons must be balanced (stand normal).
With pulled control stick they are a little bit zoomed.
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The controls have stops:
Rudder Control: Fixed stop in the rear below the rudder hinge.
Aileron Control: Fixed stop of the control shaft at frame 5.
Elevator Control: Backward – fixed stop at the seat.
Forward – adjustable stop on the control
shaft.
Airbrakes: Backwards – Is stopped by the cable of the
wheel brake. Adjusting the turnbuckle.
Forwards – Fixed stop, cross shaft lever
stops at a plywood block behind frame
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D/ Rigging & Derigging:
Rigging
1/ Clean and grease bolts and holes.
2/ First put left wing in from the side and put in the
nose bolt. Do NOT tilt fuselage.
3/ Put in right wing as mentioned in 2 above.
4/ Below main bolt (long handle) to be put in, holes
must range.
5/ By exact adjusting of wings also the upper holes
to be ranged, put in the main bolt.
6/ Main bolt to be secured with a safety pin.
7/ Aileron and airbrake linkages to be joined and
secured with safety pins.
8/ Set up the elevator unit, insert front screw and
secure with safety pin. When setting up the unit
pay attention that the control surface bell crank
have been inserted in correctly.
9/ Check that all the controls function correctly:
Airbrake release, automatic jack of release hook,
for free movement and function. Inspect for foreign
bodies.
Derigging:
Point 1 to 10 in reverse sequence.
Grease all connexions to decrease danger of corrosion.
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E/ Flying:
Trimming:
The glider can be flown with pilot weights of 140 lbs to 220 lbs,
with parachute 130 – 220 lbs.
Persons of less weight have to carry ballast (Iead sheets at
seat pad)
For adjusting the desired stick force there is a spring trimmer
installed at the stick.
Adjusting of Rudder Pedals:
Draw back pedals with heels and adjust limb in control cable to be
put into click stop. Adjusting also possible during flight.
Winch Tow:
Preset breaking piece No 11 (weak link?)
Max speed 55 knots. Note: In winch tow pulling means the same
as speed increase. At the take off push stick a little, best pitch ratio
with the stick in the normal position.
Winch tows, only at the c.g. hook.
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Aero tow:
Preset breaking piece No 1 (weak link)
Maximum speed 75 knots. Normal tows using the nose hook.
Aero tow at the c.g. hook is permissible when using textile
ropes of 100 metres (300 feet) maximum length. No
experiences of hand towing in very rough air (wave towing)
Release to be pulled completely!
Before every take off:
Make sure that the cockpit and airbrakes have locked in.
Free flight
The data mentioned is ascertained by calculation. They refer
to real flying speed (EAS).
There is the position error to be taken into consideration, see
figure 1.
Take note that with strong side slips the ASI will drop to zero
due to lateral incidence of the fuselage.
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Stalling speed at 570 lbs all up weight = 31 knots.
The lowest sinking speed in straight flight = 37 knots
The best gliding angle = 43 knots.
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In turns the lowest sinking speed is:
30o 39 knots
45o 43 knots
60o 51 knots
Just below these speeds stalling begins; the sinking speed
will increase rapidly. For the beginning is will be advisable to
take 43 knots as the normal speed for straight flight, as well
as for moderate turns.
In thermal cross-country flights the optimal speed for straight
flight is 48 knots, if the average climb in the thermal will be
1.6 ftps; corresponding to 65 knots at 6.0 ftps climb.
Here it is supposed that no life or down draft region will be
crossed. This data is only approximate, but deviation of the
optimal speed by 6 knots will reduce the average speed
marginally.
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The speed noise is unusually low; therefore it is difficult at the
beginning to hold the speed by noise alone.
The control forces and movements are also small and
demand a certain care and restraint, especially when coming
from a more inert aircraft. After becoming accustomed this
point will be found as very pleasant and in longer flights less
tiring.
Landing
Approach with about 45 - 50 knots. With the airbrakes the
gliding angle can be adjusted within wide limits. The touch
down is to be completed without the airbrakes being fully
open. Full operation of the airbrake lever will put the wheel
brake into operation. Also this lever must also be pulled
wholly, in order to avoid landing with the nose grinding on the
ground.
The glider can be held with the rudder in stalled with the
elevator control fully backwards. Stronger rudder deflections
will put the glider into a spin. Centralising all the controls will
remove the glider from the spin, easily and quickly.
Re-typed 06/01/02 by Malcolm Austin
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In high-speed flights it is necessary that the speed limits are
followed. As soon as a speed of 75 knots is passed
involuntary, the airbrakes are to be used.
Note: At higher speeds the lever becomes light and there is
a tendency for the airbrakes to self deployed once the lock
has been released. (they will pull open!)
Rain drops, hoar frost and icing can disturb the wing surfaces
so much that changed flying characteristics will become
evident. Therefore a particular care is necessary when
landing in rain; increase speed to compensate.
F/ Maintenance
Humidity is the greatest enemy of a wooden glider! Be
careful and ensure that no water remains inside the plane,
especially in corners! If there is a suspicion that water has
entered the wings or fuselage, take them into a dry room and
turn them very day so the moisture is dried out. The glider is
endangered especially when on open trailers. Ensure that a
rainproof covering is added and that no rain can splash into
the wing root.
Condensation can introduce considerable quantities of
moisture into the interior of the glider.
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Strong Sun Irradiation will injure the finish over time,
therefore the glider should not be exposed to the sun for
longer than is necessary. Use of a good quality varnish as
this will improve the durability of both the varnish and the
surfaces. The preference is for the a laminar profile which
will be enhance by a smooth finish. It is not important that
the surface shines, rather that all unevenness in dust, dirt
splashes and insects is removed.
Sealing of splits and clefts with adhesive tape will show a
gain in performance. However it is inadvisable to seal the
cockpit gaps in case a parachute bail out is required!
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