Schempp-Hirth Flugzeugbau DISCUS CS 1990 Technical specifications

Schempp-Hirth, wyroba letadel, spol. s r. o-
565 01 Chocei, Czech RePublic
FLIGHT MANUAL
for the sailp1ane
DISCUS CS
Translation of the Czech l4anual
Issue June 1990
Ttris manual must be carried on board at aII times
It refers to the sailplane
Manufacturer Schempp-Hirth, vyroba 'letadef, spo1. s r. o-
565 O.l Chocei. Czech Reolrblic
This English edition of the DISCUS CS Flight Manuaf has
been translated with care, and is accurate to the best of
our knowledge. However, in all officiaf matters the
original Czech text is the authoritat ive and definite
document-.
Page No. 14 through page No. 52 are approved by the Civil
Aircraft Inspectorate of the Czech Republic (St5tni
]eLeck5 inspekce), Prague.
I ;i;;", ;; -\/a- FLIGHT UANUAI,
Table of contents Paqe No.
1-.
l-.1
L.2
t-.3
Amendment list
General
General description
cockpit design and controls
Airspeed indicator error curve
2. operatinq Limitations
category of airworthiness
Perrnitted operations
Minirnum equiprnent
Airspeed Iimitations
Load factors
Weights
Loadingr table
Center of gravity range and positions
weight and balance log chart
Launching hooks
Weak links
Ti-re pressure
crosswind
Emergency Drocedures
Spin recovery
Canopy jettisoning and emergency exit
Safety considerations
3
5
l-3
2A
29
30
2-L
))
2.3
2.4
2.5
2.6
2.7
2.4
2.9
2.14
2.LL
2.L2
3.1
3.2
3-3
14
1"5
L6
l-9
20
20
2t
23
26
27
27
27
27
June 1990
li
lr
I
I
:tr
I
l
I

Discus CS - t/2 - rLIGHT Ir{ANUAL I
Table of contents
4. Normal operatinq procedures
4.L oaily inspection
4.2 Pre-flight. inspection
4.3 Take-off
4.3. L Aerotowing
4. 3 .2 Winch launching
4.4 Free flight
4.5 Low speed flight and stall
4.6 High speed flight
4.7 Flying with water ballast
i +.g Flying aL temperatures below freezing point 49 t)
4.10 Restricted aerobatics 51
4.LL Approach and landing 52
5. Riqqinq and de-riqqinq
5.1 Rigging
5-2 De-rigging
5.3 Storage, hangari.ng and towing
5.4 Caring for the sailplane
6. Appendix
Performance data 60 t
June L99O r
DlgcuaCS - 2_ FLIGIITH,/\}{UAI,
AmefftnqnL r!5t
(Log of Revlslons)
3L
35
3s )
35
37
39
40
43
45
53
56
57
58
l{o. Tltle Pdge Dato
rl
I rnt
,Q,
i/.i
,,.ilj
tL
'L
1. llodlfl.cnt't,on Ilulletln I{o. 1/Dlrrcrre CS
516 llay
199?
affected: S/11 O7s Cli orrri up
Cocl<p1t vetr L1-1utlon
Rlqglng l-over orni l-tscJ 54 i\prI-l /
1es) t
3" Technlcal Not.e No. 360 - 13
lllnglole optional use on alI
sorlaI nurnbers
3, 4
42 r54
55r56
/:rj''
_ Gt l)
JUn.8 !r'
t 99i-l
4. Change of the manufa
on S/N 225 CS and up Title pg
10
August
I996
vl
L
c
By the production end date on
11.11.1998 the manual was updated.
L': dI.
'oba letade
2-O43
55 o1#(
spol. s r.o,
_-1 -O6s
)hocefi
di,v1,;
I

$
DlacugCs - l- PIJIGHTHAITUAL
1. General
1.1 General DescriPtion
Is a single-seab high performance
cFRP/cFRP construction featurlng
fixed horizontal st,abillzer and
The two-piece wings each have a tri-trapezoldal
plan form, swept-back leading edge and fittro- atory"
airbrakes on the upper surface. Ailerons have
lnternal drive. Water ballast tanks are integral
compartnents ln the wing D nose, total capacity
approx. 184 liters. wing shells are of glass
fiber./foarn sandwich wlth spar flanges of carbon
fiber rovLngs and shear vebs of glaac fLber/foan
saadyich. For furthcr lmprovement of the perform-
ance, vinglete (optlon) t"y be fltted to the vin6
tips.
Fuselaqe
The pilot has a semi-reclining position. The
cockplt ls cornfortable. A one-plece canopy hlngea
sldeways. the fuselage shell is a pure gla6s flber
lay-up without sandwich and therefore ls highly
energy abaorbing. It Is stiffened towards the tail
urlth GFRP/foan sandwlch webs and the front fuselage
features a double shell on both sides and on the
bottom. The sprung undercarriage ls retractable and
ls fitted with a .whee} brake.
Horizontal tailplane
The horlzontal stablllzer is bullt ln GFRP/ foam
sandwlch and the elevator ls a pure GFRP lay-up.
The Dlscus CS
sailplane in
a T-tail (with
elevator ) .
Winqs
Vertlcal fin
Both fln and rudder are a
construction. The integral water
fln has a capacity of 6.5
cal"/1.43 Imp. caI. ).
TECHNTCAL NOTE NO. )6a * lf
cfRP/foan sandwlch
ballast tank ln the
kg (Ltr) (1.72 U.s.
June 199\
it

( 19.21
WTNGI,ETS ARE OPTIONAI,
ltlnc
Err-r.Ltes.r
ltr I qhLs
Tochnlcal DaLa
Ylng span t5.oo
l{ I nE aroa 10. 53
As?rcL ralto
LrngLh
rldlh
Ho I ehL
EoPLl, rer l ghL
tlax. A"U"H.
qlnlual
Erxl!.I
6.59 n
O.62 E
O.8l o
233
5?s
49.2t fL
t t3.88 fLu
2t.59 fL
2.03 fL
2.66 (L -l
2. 3n
(7.54 ft)
5r)
ks 514 lb
kg I 125 lb
?.sl a,a 5. ?3 I b/ f Lz
kglsz 1o.24 lb/rta
l
fu(,:M-lf &r
D,u-
Xlnq loadlnq
TECHNICAL NOTE NO" )60 - 1) June 19911
. 1" FLIGTTTTIANUAL

1.2 Cockpit Desiqn and Controls
FI.,IGHT I{ANUAI,
(Cockpit Design and Controls,ctd. )
A11 instruments and controls are hrithin easy reach
of the pilot.
(1) Instrument panel
Two screws secure the instrument cover to the panel
and to its tubular mounting frame. Panel rises under
light pressure after openi-ng the canopy.
(2) Ventilation control
Srnatl- knurLed knob on the starboard side of the cockpit.
Regulation by freeingr, moving and tightening up the knob.
Backward position - closed
Forward position - Open
In addition, the sliding window or the airscoop in
the window may be used for ventilation.
(3) The wheel brake handle is mounted on the control
stick-
(4) Rudder pedal ad-iustment
Black T-shaped grip on the right side base. of the
instrument panel console.
Forward adjustment:
Release the locking device by pulling the T-grip.
Push pedafs hrith heels into desired position and
Iet them engage the nearest notch.
Backrrard adjuetnent:
PuIl pedals back with T-grip into desired posi-
tion. Forrvard pressure with heels (not toes) will
engage pedals into the nearest notch with an
audible click.
The rudder pedals may be adjusted on the ground and
in the air.
Modif. BuTTetin No.7,/Discus CS ilay L992
Irlodif . Bulletin IIo. 1,/Discus CS l,Iay 1992
I oiscus cs - s - FLIGHT I{ANUAL I

[-rr"""= "" -- - , - Fr,rcrrr "*"* |I oiscus cs - B - F"r"r* n*r**.l
(Cockpit Design and Controls,ctd. )
(5) Launchind hook release handle
Yelloh, T-shaped handle on the left at the base of
the instrument panel console.
The winch cable (tow rope) is released by pulting
the handle.
(5) Landinq crear operatinq lever
Retract : Unlock the black handle on the right at
the seat pan support, pulI back and
engage i-n rear recess.
Extend ! Unlock black handle, push forward and
engage in rear recess.
(7) Canopy
The one-piece plexiglass canopy hinges sideways on flush
fittings. fake care that the cable restraining the open
canopy is attached.
(8) Canopy lockino device
Lever control with red knob on the 1eft on the
canopy frame"
Backnard position .... canopy locked
To open the canopy swing lever forward and raise
canopy.
(9) Canopv emerqencv iettisonincr device
Sliding red knob on the right on the canopy frame.
Backlrard position .... locked
To jettison the canopy, first swing the locking
lever on the left on the canopy frarne forward, raise
canopy.push the red jettison knob on the right on
the inner skj-n forward and push canopy away.
June 1990
(Cockpit Design and Control-s, ctd.)
(10) Winq and fin tank water ballast dumpinq device
Black ba1l-shaped knob on the right in the
middfe of the GFRP inner skin.
Forward position : Valves closed
Backward position = Valves open
To lock the valves open, push knob downwards
into recess.
(11) Airbrake lever
Blue Iever on the left hand side of the
cockpit.
Lever projects downwards,
Forward position
Pulled back approx.
40 rur (1.6 in. )
Pulled fully back
= airbrakes closed
and locked
= unlocked
= airbrakes fully
extended
(12) Elevator trin
Green knob on the 1eft at the seat mol"d
support.
The spring operated elevator trim is
gradually adjusted by rnoving the green
knob inwards, sliding it info the desired
position and releasinq it to lo;k.
Forward position
Backward position = nose heavy
: tail heavlr
,June 199o

( 13 )
(cockpit Design and Controls,ctd. )
parachute riD cord attachment (not pictured)
Red ring, situated at the front of the
fuselage steel tube framework, left hand
side.
Discus CS - 10 - FLIGHT MANUAL
(Cockpi-t Des-ign and Controls, ctd. )
C<r-cpjt -placards (oper:ating data and miscel laneous )
Ldert.j-ficatj.on pl.ate (fire proof )
o
o
oSchempp-Hirth, vliroba letadel, s. r. o.
Chocei, Czech Republic
Type
S/N.Year of Production
O TcNo
Weak links for towing:
xinun 680 ilaN (14 99 1b)
Main wheel tire pressure:
,p
above 360 kq (794 Ib) 4.5 bar (64 psi)
$r
Q-p er aI-1 r'r-q "- l:, uila-t-r-o ns
Max permitted a1l-up weight: 525 kg (1157 lb)
Max permiLted speeds (IAs) km/h kt mph
Max per:mitted speed 250 135 155
in rough air 200 108 124
Maneuverirrg speed 20O 108 724
on aer:otow 180 91 l\2
Aut,omobile and winch launch 150 81 93
Operating J.imits when fin tank is used:
Mini mum gronnrl
temperature L13.5 t] 24 31 38
r55 63 15 BB 1OO
Maximum absolut
ceili nq m1500 2000 3000 4000 5000 ft 4900 6500 9800 3100 6400
June l-990
Augu:;L 1996
t
l
I
l
I
I

[;;;;; -11 -TI,IGHT UANUAL
(cockpit Design and Controls,ctd. )
Load on pl-J.otrs seat
(pilot and parachute)
Maximum load 110 kq (242'5 Ib):
Minimum Ioad 70 kq (154.3 lb)-'
Pitotrs weight of less than 70 kg
(l-54.3 Ib) must be raised bY using
trirn ballast
* As the actuaL minimum or maximum seat Load of this
saiTplane to which this nanual refers nay d.iffer
froi the above typical weights, the placard in the
cocpit must show the actuaf weights urhich are aLso
to'be entered in the loq sheet (see paqe 26). -3
o
o
o
o
o
check list before take-off
Water in fin tank?
Loading charts checked?
Parachute securely fastened?
Safety harness secured and tight?
Back rest and pedals in comfortable
position?
A11 controls and instruments
accessible?
Airbrakes locked after functioning
check?
AI1 control surfaces checked with
assistant for full and free movement
in correct sense?
Triner correctl-y set?
Canopy closed and locked?
o
o
Aerobatics: without water ballast
the following maneuvers are permitted:
a) Inside loops c) Spins
b) Stalled Turns d) Lazy Eight
Baggage compartment
MaxinaL Load: 2.0 kg (4.4 1b)
(cockpit Design and Controls,ctd. )
Cockpit controls - markinqs
Discus cS -L2- FLTGHT I{ANUAL I
gear DoWN
heavy TAIL
gear UP
heavy NOSE
Trimmer - green knob
#-* +)
Pedal. adjustment
Ventilation
Yel-low tow release handle
Airbrakes - blue handte
@
ft-canopy opening 1e red knobs
right-canopy jettisoning
water ballast dumping knob
June 1990 June 1990

t'-
I Dlscus cs -Lza- TI,IGHT I,IA}IUAIJ l- ,t=""= "" - -- 13 -FLIGHT I,IANUAI,
(cockpit Design and controls,ctd. )
Fin tank label: (riqht side only) 1.3 Airspeed indicator svstem errors
Errors in indicated airspeed caused by Pitot/Static
pressure errors may be read off from the calibration
chart be1ow.
Position of the pressure ports:
Static preEsure: Fuselage, approx. l-scm (5.9in) below
main spar cut-out and on fuselage tail boom, approx.
SOcn (31-5in) forward of the base of the fin.
Pitot pressure: on the leading edge of the fin.
'k AII airspeeds shown in thj-s manual are indicated
r airspeeds ( IAS ) as registered by the airspeed
indicator. The calibration curve is also valid for
winch launching and aerotow.
mph kt km/h.
149 130 240 Pitot tube
in fin 7
_l D
+Is cu scs
3
H
8
.u
!
s,fc .226 ,g/m3
/tt
Calibrated Attr
irspeed (CAS)
99
87
75
62
::
137 119 220
124 108 200
112 97 180
86 160
76 140
65 120
54 100
50 43 B0
km/h B0
kt 43
mph 50
120
65
75
160
86
99
2N
108
124
240
130
149
June l-99O
I
I
\ , u,, *u,,
I +b
I *s
[ +-+
! +3
I oz
I *,
:ryt:::::::::::aa:w..!:::
June 1990

-14- FLIGHT !,TANUAL
2. operatinq Iimitations
2.L Categorv of Airworthiness
Category ilU" (Utility) according to JAR 22.
According to the requirements of JAR 22, full
control surface deflections may be applied up to the
maneuvering speed VO.
At higher speeds, when using fuII control surface
deflections, it would be possible to exceed the
stress Iimits of the sailplane.
Forthisreason,fuIIdef1ectionofcontro}smust
not be used at speeds above 2OO kn/h (l-08 kt, L24 4
mph).
At rnaximum permitted speed V^ro : 25O kn/h (135 kt,
1,55 mph), only a maximum of"5ne third of the fuII
control deflection is perrnitted.
For the elevator, the defl-ections at Vf,rF are even
considerably small-er and depend on tlie' permitted
maneuvering load factors.
In norrnal weather conditions, this sailplane can be
flown at speeds up to VNF : 250 km/h (135 kt, 1-55
mph) without problerns.
In severe turbulence, i.e. wave rotors, '
thunderstorms, visible whirtwinds and when crossing
mountain ridges, VOO = 200 krn/h (1OB kt, l-24 mph)
must not be exceedeef.-
-15- FLIGHT I{,ANUAL
2.2 Permitted operations
1". vFR Flylng in daytine
(Minimum equipment according to section 2.3a)"
2. Cloud Flying
(Minimum equiprnent according to section 2.3b).
3. Restricted Aerobatics:
The follovring aerobatics maneuvers are permitted:
a) Inside Loop
b) spins
c) Stalled Turn
d) Lazy Eiqht
In addition to the equiprnent listed in section 2.3
it is recommended to equip the sailplane with
accelerometer (3 hands, resettable), if it is to be
used for aerobatics.
f oi."o= ""
,i
June 1"990 June 1990

[ -of=""= "t - 16 - FLIGHT r'taNuar, I
2.3 Minirnun Equipment
Instruments and other basic equipment must be of an
approved type and should be selected from the list
in the Maintenace Manual.
a ) Normal operations
1 Airspeed indi.cator
range up to 300 km/h (162 kt, L86 mph), with
colour narkings shown on page 18. kk
.,?
l- Altineter
Four-piece safety harness
( symmetrical )
Automatic or manual Parachute,
or a seat-back cushion (thickness approx. 8 cm
(3,15 in) when compressed),
outside air temperature Lndicator
with sensor (red tine at zoc (36oF) in minus
temperature range).
il
the equipment listed in section
Turn & bank indlcator with slip baLI
Variometer
VIIF - Transceiver
Magnetic compass
Note:
From experience gained to date it appeats that
the A.S.I. system, as installed, remains tu17y
operational when flying in cfouds.
Recommended additional equipment for:
Cloud flying
Artificial horizont
clock
Restricted aerobatics
Accelerometer (3 hands, resettable)
Note:
t-
I Discus cs - t7 -FI,IGHT I.IANUAI I
(Minimum Equipnent,ctd. )
b) Cloud F1vinq
In addition to
a):
For structural
instrument panel reasons the weight of the
and instrurnents must not exceed
10 kq (22 lb).
June 1990 June L990
-,$

(Minimum EquiPment,ctd' )
OPeratinq Instructions
Fliqht and Maintenance Manual
) Z Data and Reference Placards
Airspeed Indicator Colour l"larkinqs
)
)
I
I plecus cS - 19 - FLIGHI I'IANUAL I
2. 4 aircpeed*linitE-(IAg-I
kn/h kt nph
Maximum permitted
speed Vff 250 1"3 5l-55
Maximum permitted
speed in rough air V* 200 l-08 L24
Maneuvering
speed VA 200 108 L24
Maximum permitted
speed on aerotow VT 180 97 112
Maximum speed
on winch launch- VW l-50 81 93
*Mu*inr* pernitted speed on autonobile & vinch
Taunch
Please note that with increasing altitude true
airspeed (TAS) increases versus indicated airspeed
(rAS)"
This is of no consequence with regard to the
stressing of the sailplane. However, for flutter
prevention the following speeds (IAs) rnust not be
exceeded;
kn/h nph kt
Maxirnum
permitted sPeed V*B 250 155 l-3 5
Maneuvering
speed VA 200 L24 108
1-.1- x Stalling
speed 1.L x Vs1 95 59 51
Green arc
(normal range) 95..200 59. .L24 5l-. .108
Yellow arc
(caution range) 200. : 250 l-24. .1s5 l-08. .135
Red radial line
(never exceed) 250 155 13.5
YeIlow arrow
(approach sPeed) t-l_5 7L 62
The statling speed of which the airspeed indicator
markings ire - based refers to the following
configuration:
a) Airbrakes : Closed
b) Maximurn weight t W*.* = 525 kg (l"l-57 Ib)
June l-99o
A].titude v( rAs )
mft km/h kt mph
0
t-000
2000
3000
4000
5000
o
3 280
6550
9840
t-3 1-20
l-64 00
250
250
250
250
250
243
l-3 5
l-3 5
1-3 5
135
l-3 5
t3L
155
155
L55
15s
l-55
151
Altitude v( rAs )
mft kn/h kt nph
6000
7000
8000
9000
l-0000
12000
t-9680
22960
26240
29520
3 2800
39360
230
2T7
205
193
LA2
l-58
124
1L7
l-11-
l-04
98
85
L43
1-3 5
L27
l-20
1-t- 3
98
June 1990

Discus CS -20-
2.5 Load Factors
The following
exceeded: maneuvering load factors must not be
at Ve = 2oo kn,zh (1og kt, 124 nPh)
n : + 5.3
n=-2.55
at V*"= 250 km/h (135 kt, 155 nph)
n = + 4.0
n : - 1.5
Airbrakes closed.
Airbrakes extended : Maximum n : + 3.5.
2.6 weiqhts
FLIGHT IT,IANUAIJ I
IDiscus cs -27- FLIGET }fANUAI,
2.7 Loadinq Table
Seat foad (pilot and parachute):
Mininum 70 kq (1s4.3 tb)
Maximun l-l-O kg (242.5 lb)
As the actuaf nininum or maxinun seat load
of this sailpTane to which this nanual refers
nay differ from the above typical veights, the
seat load pfacard in the cockpit nust show the
actuaf weiqhts fron the log chart on page 26.
Pil-ot's weight of Less than this rninimum seat }oad
must be raised by using trirn ballast.
1. Ballast (lead or sand cushion) must be securely
held in place by attaching it to the lap belt
brackets.
2. Ballast by means of lead plates can be instafled
into the fuselage nose cone. 2.2 kg (4.85 lb)
correspond to 5.0 kg (l-1.0 Ib) pilot weight. The
installation point is 17L5 mm (67.52 in) ahead of
datun (BE).
Neither the rnax. permitted all-up weight nor the
maximum weight of the non-lifting parts may be
exceeded.
Centre of gravitv (C.G. ) of the pilot:
(with parachute or back cushion)
450 mm (17.72 in) ahead of datum (BE).
June 1990
i
kg 1b
Empty weight
(approx. )233 514
Maxirnum pernitted
alf-up weight 525 1157
llaximum weight of
non-Iifting parts 240 529
For rnaximun permitted water bal-last refer to section
2.7
June 1990

I niscus Cs - 22 -TLIGHT I,IANUAL [-rt.""r ""
(Loading Table,ctd. )
Loadinq Table with Water Ballast
Max permitted all-uP weight
(including water ballast)
Lever arn of water ballast
aft of datum (BE)
....525 kg (11s7 tb)
.... 203 nn (7.99 in)
-22a- FLIGHT I,IANUAL
(Loading Table,ctd. )
Loadinq Table When Usinq The Fin Tank
In order to shift the center of gravity close to its
aft limit (favourable in terns of perforrnance),
water ballast may be carried in a fin tank (nFT) to
compensate for the nose heavy moment of ^*ater
baLlast in the wing (m971).
The deterrnination of the ballast quantity is done
with the aid of the diagrarn on page 22 d.
:r': .::1
Table of water ballast at various empty weights and
seat loads (pilot incl. parachute):
Baggagre Compartment
Max. permitted load in baggage compartment:
2.o kg (4.4 rb)
This load must be considered when the maximum
permitted water ballast load is deterrnined.
Lever arm of baggage aft of datum (BE):
88O nn (34.65 in)
.i:r:1
EEPL}, SeaL load pilol. and parachute kg (tb)
k9f tb 70 (154) aO (r?6) 90 (194) 100 (220) llo (243')
220 485 184 4A-6 40.5 1A4 4A.6 40. la4 4a.6 40.5 1a4 44.6 40.5 ta4 4a- 5 40.5
225 496 184 4a.6 40.5 184 4a.5 40.5 la4 4a.5 40.5 1A4 4A.5 40-5 ta4 48.6 40-5
230 507 784 48.6 44.5 ta4 44.6 40-5 t84 4A.5 40.5 1A4 48.6 40_s 184 4A-5 40.5
235 514 ,a4 44.6 40.5 1a4 44.6 40.5 1A4 4A.6 40-5 1A4 4A-6 AO.5 lao 47.5 39.6
?,ao 529 184 48.6 40.5 ta4 48.6 40.5 1A4 4a.6 40.5 1A4 44.6 40.5 175 46.2 3e.5
245 540 ta4 4a.6 40.s 7A4 4a-6 40-5 7a4 48.6 40.5 lao 47.s 39.5 17(J 44-9 37.4
250 s51 1a4 43.6 40.s la4 4a-6 40-5 1a4 4a.6 40.5 t?5 46.2 3A.5 165 43.6 36.3
) --.riaers *x) ...U.Ii.Gallons xxx) ..-Inp.Gallons
Hater ballasl- in boLh ving Lanks
June 1990 June l-990

t-
I oi="or c" - 22b - FLTGHT'*"=--l
(Loading Table,ctd. )
Example
for the determination of the ballast quantity:
Total vrater ballast in both wing tanks
rnr4.1 = 70 kg (liters)
Resulting water ballast in fin tank as shown in
the diagram on Page 22 d:
rnF' = 2'O kg (liters)
As the scale on the fin tank is graduated for
fu1l kilograms (liters) only, a quantity of
2.0 kg (liters)
is filled in fin tank.
of the
Discus cs -22c- FI,IGIIT I.{ANUAL
(Loading Table,Using Fin Tank,ctd. )
When deternining the quantity of water ballast for
the fin tank, bear in nind that the maximum
permitted payload (see log chart, page 26) nust not
be exceeded. Check as follows:
mprl,oT + mr, < (1ess or equal to the max. permitted
payload shown on page 26).
In order to avoid that the maximum permitted gross
hreight is exceeded, the ballast in the fin tank must
also be considered when determining the rnaximum
allowable water ballast for the wing tanks.
tlon:
The fin tank should never be used when there
is the danger of the water ballast beconing
frozen "
Flying conditions must
table: conform with the following
ini l"nng linits for fin tank:
Minimurn
ground
temperature
oc L3. 5t7 24 31 38
oF 56 63 75 88 100
Maximum
absolute
ceiling ml-500 2000 3000 4000 5000 ft 4900 5500 9800 13 100 16400
observe the outside air ternperature indicator.
The temperature must not drop below
z oc (35 oF).
June 1990
June 1990

I oi=""" "" -22d- uo-n= *ul__l Discus cS -23-
2.a C.G. Positions
a) In-fliqht c .G. position
sailplane attitude : TaiI jacked up such that
a wedge-shaped block l-00 i 4.4, placed on the
fuselage tail boom, is horizontal along its upper
edge.
Datum (BE)
Max. forward
C.c. position ...
Max. rearldard
C.G" position ... 400 rnm (l-5.75 in)
aft of datun (BE)
Make sure that the rnaximum pernitted rearward
C.c. position is not exceeded - this is ensured
when the minimum seat load (pilot and parachute)
is observed.
A lower seat load nust be compensated by ballast.
(See section 2.7 , rrloading tablett).
Empty weight C.G. position
After repair, repainting, installation of
additional equipment, rnodifications etc. the
center of gravity must be re-determined by
weighing the sailptane; in any case the Discus CS
should be re-weighted every four years" Make sure
that the empty C.c. is within the permitted
range- If necessary, compensating ballast weight
must be installed.
When the empty weight C.c. lirnits and the loading
table are observed, the C.G. position in flight
$ri1l be within the permitted range.
rl,rcHr I{ANUAL I
(Loading Table,Using Fin Tank,ctd. )
m-- Water ballast in fin tank:
Table for the determination of fin tank
quantity. (See example on page 22 b) ballast
June 1-990
Wing leading edge at root rib
250 nm (10.24 in)
aft of datum (BE)
1..::aa:a:4
b)
(rn.s)
113-+-2e.
liters
x. wing water ballast- m
a
x
f
i
n
US.gallons o 0. 26 0.53 O.79 1-. 06 l-.32 1.58
Im.gallons O 0.22 o.44 0.66 0.88 1.10 1.32
June 1990

DiBcuB cS -24a- TLIGHT I.IANUAL
(C.G. Positions, ctd.)
(c.G. Positions, ctd' )
Thedeterminationofthec.G'rangesasshowninthe
diaqrams on page is a and 25 B is done with the
foltowing seat loads:
ia
Forward
C.G. Positions:
Rearward
c.G. Positions:
With a naxi-num seat load of 110 kg
(itz.s Ib) and with max' Permitted
water ballast
',.,]^
With various rninimurn seat loads and 't
,iti, 2.o kg (4.4 lb) load in the
baggage comPartment
For easier determination of the 'rempty" weight
C.G.position the iable on page 24 A shows' at
;;;i;;;-;;ply weiqnts, the naxirnum-permissibte loads
;;--6; iiir' =r.ia i"i wheel - ir installed) with
i"rl""= =.it loads (with reference to the rearnost
c/c position).
Just determine the actual load on the tail skid (or
wheel ) with tne sailplane being . in weighing attitude
i."i"'rn""r on the qil""a, tail jacked up as described
on page 23).
If the determined load on the tail skid (or wheel -.if
installed) is below the value shown on page 24 A' the
c.c. p"=iiion is within the permitted range'
Enpty
weight Load on tail wheel with a seat load of: 70 1-54 75 165 80 L76 85 l-87
k9 1b kg Ib kg 1b kg 1b kg Ib
220 48s 2A.7 63.2 29.7 65"5 30.8 57.9 3L.8 70.2
225 496 29.O 53.9 30.o 56.2 31.1 68.6 32.2 71-.O
230 507 29 .4 64 .9 30.4 67.1 3L.5 69.5 32.4 7L.5
235 518 29.7 65.5 30"7 67.7 3L.8 70.2 32.8 72.4
240 529 30.0 66. 231.1 68"5 32.O 70.6 33.1 73.0
245 540 30.3 66.9 31.4 69.3 32.4 7L.5 33.5 73.9
250 551 30.7 67.7 3L.7 69 "9 32.7 7 2 .L 33.8 74.6
255 562 31.O 68.4 32.1 70.8 33.O 72.8 34.L 75.2
260 573 31.3 69.1 32.3 7L.3 33.4 73.7 34.4 75.9
June 1990
June 1"990

Diacus cs - 25a - I'LIGHT MANUAIJ
(C.c. Positions, ctd.)
Ernptv weight C.G. Range
Permitted forrrard C.G. position at maximum seat load
of tL0 kg (242.5 Ib) and maximum pernitted water
ballast.
Enpty
Weight C.G. aft
of datun
1b
kg 1n
nm
220 444
22L 486
222 4A9
223 49r.
224 493
225 49s
226 498
227 500
224 502
229 504
230 505.8
23L 509.O
232 sLL.2
233 513.4
234 515.6
235 5L7.4
236 520.O
237 522.2
234 524.4
239 526.6
I
o
2
4
6
7
9
2
4
6
26.L
26.O
26.O
25.9
25.8
25.O
25 "O
24.9
24.8
24.8
653.9 25.7
652.O 25.7
650.2 25.6
64A.4 25.5
646.6 25.5
644.9 25.4
643.1 25.3
64t.3 25.2
639.6 25.2
637.8 25.L
663.3
661.4
659.5
657 .6
655.7
636. O
634.3
632.5
630.8
529.L
Enpty
weight c.G. aft
of datum
lbkg 1nnm
260 572.9
240 528.8
24L 531-.0
242 53X.2
243 53s.4
244 537.6
245 539.8
246 542.O
247 544.2
244 546.4
249 548.6
250 550.8
25L 5s3. r-
252 555.3
253 557.5
254 5s9.7
255 56t-.9
256 564.1
257 566.3
258 568,5
259 570.7
627.3 24.7
625.6 24.6
623.8 24.6
522.L 24.5
620.4 24.4
5L8.7 24.4
6L7.O 24.3
615.3 24.2
513.5 24.2
6lL.9 24 .L
6LO.2 24.4
608.5 24.O
506.9 23.9
605.2 23 .8
603"6 23.8
602.O 23.7
600.4 23.6
598.8 23.6
597 .2 23.5
595.6 23.4
594. 1 23 .4
Max. permitted absolute ultimate weight
A.u.W. = 525 kg (11s7 tb)
June 1990
I

(C.G. PosiLions, cLd.) Ernpty HeighL Cent"er of GraviLy Range
Ilax. perm i LLed absol uLe ul L i naLe ve'i ghL
A.U.y. = 525 ks (ttSZ tb)
Pernltted Rearvard C.G. position
EmpLy
He i ghL Ilininun Seat Load of
ker lb kg tu kg lb kg tb
70 754 75 155 ao 1?6 85 1A7
kg lb 3l ln DTI ln in EE EM ln
240 528.8
247 531.O
242 533.2
243 535.4
244 537.6
245 539.8
26 542.O
247 544.2
244 s46.4
249 54A.6
250 550.8
251 553.1
252 555.3
253 ss7.5
254 559.7
255 561 .9
256 564.1
257 s55.3
258 s68. s
259 570.7
260 572.9
543.8 25.3
642.7 25 .3
641-7 25-3
640 -7 25 .2
639 -7 25 .2
634.7 25.1
637.7 25. t
536.7 25. 1
635_8 25.O
634.8 25.O
633.9 25.O
632.9 24.9
632.O 24.9
631 .1 24.a
630.2 24.4
629 .3 24. a
62e.4 24.7
627.5 24.7
626 . 6 24.7
525 .7 24. 6
624.9 24.6
662.O 2F.1
660.9 26.O
559-a 26.O
658. a 25.9
657 -7 25.9
6s6 -7 25.9
655.7 25.8
654.6 25.A
6s3.6 25.?
652.6 25 .7
65r .5 2s.7
550.5 25.6
649.6 25.6
64A _6 25. 5
64? -? 25.5
646-;, 25. s
645.7 25.4
644.A cS.a
543-9 25.4
642-9 25.3
642.O 25.3
679.3 26
672.4 26 .5
671 -3 26.4
670-2 26.4
669.1 26.3
658. 1 26.3
667.O 26.3
566_O 26.2
664.9 26.2
653.9 26. t
662.9 26. t
667.9 26.1
660 -9 26.O
659.9 25.O
658.9 25.9
554.O 25.9
674.7 26.7
577 -O 26.7
575.8 26.6
674.7 25.6
573 .5 26 .5
697 .2 2? .4
696-0 2? .4
694-A 27 .4
693.6 2?.3
692.3 27 .3
691 .1 27.2
689 -9 27 .2
68a-A 27.I
687-6 27.I
646.4 27 .O
585.3 27.O
684.1 26.9
543- O 26.9
681.a 26.a
6A0-" 26.A
679.6 26.A
67a.5 26.7
677 -4 26.7
576.3 26 .6
67s-2 26.6
674. t 26.5
PerniLted Rearvard C-G, poslLion
EnpLy
He i ghl 11 lnlnum SeaL Load of
ks lb kg rb kg lb ksr lb
'/o 154 75 155 80 176 85 7A7
kg lb nfr tn IIL in nn ln nn in
220 484.7
221 486.e
222 489.2
223 491.4
224 493.6
225 495.4
226 494.O
227 500.2
22a 502.4
229 504.6
230 505.8
231 509.O
232 51t.2
233 513.4
234 5t5-6
235 517-A
236 520.O
237 522.2
23A 524.4
239 526.6
666. O 26.2
664.9 26.2
663.7 26. I
662.s 26.1
667.4 26.O
660.2 26.O
653. 4 25.7
652.3 25.7
651 .2 2,5 .6
650.1 25.6
649.O 25.6
648. O 25
646.9 25
645. a 25
644-A 25
559- r 25.9
657 .9 25.9
655.8 25.9
655.7 25.4
554.s 25.a
5
5
4
4
6A4.9 27.O
6a3.5 26.9
6a2.4 26 .9
6At -2 26.a
6ao.o 26.a
6?a.a 26.7
666-3 26.2
565.2 26.2
664.1 26.1
663.4 26.7
677 -6 26.7
676.5 26.6
675-3 25.6
574- t 26.5
673.O 26.5
571 .9 26.5
570 -'/ 26 _ 4
659.6 25.4
668.5 26 -3
667 - 4 26.3
705. O 27 .A
7A3.7 27.7
702.3 27.6
?o1.o 27.6
599.6 27 .5
59A.3 27 .5
690.4 27 .2
689. X 2?. L
687.9 2? .7
6A6.6 27.O
685-4 27.O
684. 1. 26 .9
6A2.9 26.9
6at .7 25 .4
680. s 26.4
696.9 27.4
695.6 27.4
694.3 27.3
593.0 27 .3
597 -7 27.2
724.O 2A
722.6 2A
721-t 2a
7L9.7 2A
7ta-3 2a
716-9 2A
775-6 2A
714.2 2a
772.8 2A
711.5 28
71o.7 2a
4
4
3
3
2
.>
1
I
o
o
70a.8 27 .9
707.5 27.9
706.2 27.8
704.9 27 .8
703-6 27 -7
702.3 iZ . S
707 .O 27 .5
699.a 27 .6
59a.5 2? .5
June l99O

I
I Discus CS -26
\{EIGHT AND BALLAI.ICE LOG CHART valid for Senia1'Numberff,5E-
DaLe of
ve i srhi ng iil ?' ){1 tp$ffi
InspecLor
S i gnat ure
SLane
EmfrLy
ueighL (kg)
Ecru i pmenL
I isL daLed 'g ,;" ){i 3#ffiffi
Enpt.y weighL
C. G. posiLion
aft, of
datum (BE) (rnst)
HeigrhL of
pi lot and
parachuLe (ks)
IIax i mum
payl oaci ( kg)
Hax. perniLted
r.raler baI l asL
a.L max payload (kg)
x) max seaL load not- Lo exceed 11O kgr
June 1994