SCHEMPP-HIRTH FLUGZEUGBAU GMBH, KIRCHHEIM/TECK SCHEMPP-HIRTH FLUGZEUGBAU GMBH, KIRCHHEIM/TECK Duo Discus FLIGHT MANUAL FLIGHT :for MAN UA L 0.1 Record of revisions Sailplane Any revIsions of the present manual, except actual weighing data, must be recorded in the following table and in the case of approved sections be en- dorsed by the responsible airworthiness authority. Model Serial-No. Registr.-No. Date of' Issue 414 N9 0 B P october 1993 The new or amended text in the revised page will be indicated by a black vertical line in the left hand margin, and the revision number and the date will be shown on the bottom left hand side ot the page. Pages as indicated by "LBA-app." are approved by LUFTFAHRT BUNDESAMT Signature Authority Stamp Original date 21, Marz of' approval This sailplane is to be operated in compliance with information and limitations contained herein. Approval translation has been done by best and jUdgement. In any case the original text in German language is authoritative. 0.1.1
74
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SCHEMPP-HIRTH FLUGZEUGBAU GMBH, … FLUGZEUGBAU GMBH, KIRCHHEIM/TECK SCHEMPP-HIRTH FLUGZEUGBAU GMBH, KIRCHHEIM/TECK Duo Discus FLIGHT MANUAL FLIGHT:for MAN U A L 0.1 Record of revisions
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SailplaneAny revIsions of the present manual, except actualweighing data, must be recorded in the followingtable and in the case of approved sections be endorsed by the responsible airworthiness authority.
Model
Serial-No.
Registr.-No.
Date of' Issue
414
N 9 0 B P
october 1993
The new or amended text in the revised page will beindicated by a black vertical line in the left handmargin, and the revision number and the date willbe shown on the bottom left hand side ot the page.
Pages as indicated by "LBA-app." are approvedby
LUFTFAHRT BUNDESAMT
Signature
Authority
Stamp
Original date21, Marz t9S~ of' approval
This sailplane is to be operated in compliancewith information and limitations containedherein.
Approval o~ translation has been done by best kno~ledge and jUdgement.In any case the original text in German language is authoritative.
0.1.1
SCHEMPP-HIRTH FLUGZEUGBAU GmbH., KIRCHHEIM/TECK
Duo Discus FLUGHANDBUCH
Duo Discus
SCHEMPP-HIRTH FLUGZEUGBAU GmbH.• KIRCHHEIMrrECK
FLUGHANDBUCH / FLIGHTMANUAL
0.1 Erfassung der Berichtigungen I Record of revisions
Lfd.Hr. Datum Datu. der Datum
der der Anerkennunq der ZeichenBerichtigunq Abschnitt seiten Berichtigung Bezug durch d. LBA Einarbeitung /Unterschrift
Revision Affected Affected Date of Date of Date of
Ho. section pages issue Approval by InsertionReference LBA signature
This sailplane, model designationThe Flight Manual for this sailplane has beenprepared to provide pilots and instructors withinformation for the safe and efficient operationof the "Duo Discus". " Duo Discus",
This manual includes the material required to befurnished to the pilot by "JAR", Part 22.
It also contains supplemental data supplied bythe manufacturer of the sailplane.
has been approved by the Luftfahrt Bundesamt (LBA)in compliance with "JAR", Part 22, effective onJune 27, 1989 (Change 4 of the English OriginalIssue), including additional Amendments 22/90/1,22/91/1 and 22/92/1.
The LBA Type Certificate is No. 396 and wasissued on March 21st, 1994
The following definitions apply to warnings,cautions and notes used in this flight manuall
The "Duo Discus" is a two-seat sailplane for advancedtraining and cross-country flying, constructed fromglass and carbon fiber reinforced plastIc (GFRP/CFRP),featuring a T-tail (with fixed horiz. stabilizer andelevator).
"WARNING"
"CAUTION"
"NOTE"
means that the non-observation of thecorresponding procedure leads to animmediate or important degradation ofthe flight safety
means that the non-observation of thecorresponding procedure leads to aminor or to a more or less long termdegradation of the flight safety
draws the attention on any specialitem not directly related to safety,but which is important or unusual.
.J!i~g_
The wing is four-stage trapezoid in planform, consistsof two main panels with tip extension (having a sweptback leading edge) and has double-panel "Schempp-Hirth"type airbrakes on the upper surface. Ailerons are internally driven.The integral water ballast tanks have a total capacityof approx. 198 Liter (52.3 US Gal., 43.5 IMP Gal.).
The wing shells are a glass fiber/foam-sandwich construction with spar flanges of carbon fiber rovingsand shear webs made as a GFRP/foam-sandwich.
!.u!!..e.!.a~e_
The cockpit is comfortable and features two seats intandem. The one-piece canopy hinges sideways and opensto the right. The fuselage is constructed as a pure glassfiber non-sandwich shell and is thus highly energy absorbing. While its aft section is stiffened by GFRP/foamsandwich bulkheads and webs, the cockpit region is reinforced by a double skin on the sides, with integratedcanopy coaming frame and seat pan mounting flanges. Themain wheel is retractable and features a hydraulic discbrake I nose wheel and tail wheel (or skid) are fixed.
~o~i~o~t~l_t~i~p~a~e_
The horiz. tailplane consists of a fixed stabilizer withelevator. The stabilizer is a GFRP/foam-sandwich construction with CFRP-reinforcements, the elevator halves are apure CFRP/GFRP shell.The spring trim is gradually adjustable by a leverresting against a threaded rod.
Vertical tail
Fin and rudder are constructed as a GFRP/foam-sandwich.On request a water ballast trim tank with a capacity of11 Liter (2.9 US Gal., 2.4 IMP Gal.) is provided in thefin •
.Q.o~t!:.o.!.s_
All controls are automatically hooked up when the sailplane is rigged.
Section 2 includes operating limitations, instrument markings and basic placards necessary forsafely operating the sailplane, its standardsystems and standard equipment.
The limitations included in this section and insection 9 have been approved by the LuftfahrtBundesamt (LBA), Braunschweig.
When flown solo, the "Duo Discus" is controlled fromthe :front seat.
Observe the minimum load on the front seat ifnecessary, ballast must be installed to bring theload up to a permissible figure. See also section6.21"Weight and Balance Record / Permitted PayloadRange" .
2.11 Kinds of operation
With the prescribed minimum equipment installed(see page 2.12), the "Duo Discus" is approved for
VFR-flying in daytime.
october 1993Revision
LBA-app.2.10
October 1993Revision
LBA-app.2.11
Duo Discus
SCHEMPP-HIRTH FLUGZEUGBAU GMBH, KIRCHHEIM/TECK
FLIGHT MANUALDuo Discus
SCHEMPP-HIRTH FLUGZEUGBAU GMBH, KIRCHHEIM/TECK
FLIGHT MANUAL
2.12 Minimum equipment
Instruments and other basic equipment must be of anapproved type and should be selected from the listin the Maintenance Manual.
2 Airspeed indicator (range up to JOO km/h. 162 kt, 186 mph)with colour markings according to page 2.3
2.1J Aerotow and winch launch
Aerotow
Maximum towing speed
Weak link in tow rope :
180 km/h (97 kt, 112 mph)
700 - 910 daN (15432006 lb)
2 Altimeter
Outside air temperature indicator (OAT) with sensor(when Clying with water ballast, red line at +2° C)
2 Four-piece safety harnesses (symmetrical)
2 Automatic or manual parachutes
or
2 Back cushions (thickness approx. 10 cm/J.9 in.when compressed)
Minimum length oftow rope
Tow rope material
Winch launch
JO m
Hemp or Nylon
(98 ft)
Caution:
The sensor for the OAT must be installed in theventilation air intake.
For structural reasons the mass of each instrumentpanel with instruments in place must not exceed10 kg (22 lb).
--- --- rear atseat load choice seal load choice 243"lb --- ---Loads of less than the above minimum must be I Loads of less than the above minimum must beraised by using trim ballast· see Instructions given raised by using trim ballast· see Instructions givenin seclion 6.2 of the Flight Manual. i in section 6.2 of the Flight Manual. The value shown
in parenthesis may be used after having thoroughlychecked the ballast quantity In the fin tank and theappropriate loading chart.
" /Is tit" actual mlnlmum or maximum load on the seats of this "Duo Discus" (towhich Lhis manual refers) may differ from these typical weights, tha placardsin the cockpit must always show the actual weights, which are also to beentered in Lhe log chart see page 6.2.3.
Note;
Further placardsare ehown in theMaintenance Manual
I WEAK LINK FOR TOWING Ifor Aerotow and Winch launch:
max. 910 daN (2006 Ib)
I TIRE PRESSURE INose wheel: 3.0 bar (43 psi)Main wheel: 4.0 bar (57 psi)Tail wheel(if installed) 3.0 bar (43 psi)
October 1993Revision
LBA-app.2.14 .Tanuary ;;'000
nevi I'd on 5TN 19(j - 5MD 396 - 10
LBA-app.2.15
Duo Discus
SCHEMPP-HIRTH FLUGZEUGBAU GMBH, KIRCHHEIMjTECK
4.
4.1
4.2
4.3
4.4
4.5.1
4.5.3
4.5.4
4.5.5
4.5.6
4.5.7
4.5.8
4.5.9
October 1993Revision
Section 4
Normal operating procedures
Introduction
Rigging and de-rigging
Daily inspection
Pre-flight inspection
Normal procedures and recommended speeds
Methods of launching
(roserved)
Flight
Approach
Landing
Flight vith vater ballast
High altitude flight
Flight in rain
Aerobatics
4.1.1
SCHEMPP-HIRTH FLUGZEUGBAU GMBH, KlRCHHEIM/TECK
Duo Discus
SCHEMPP-HIRTH FLUGZEUGBAU GMBH, KIRCHHEIM/TECK
FLIGHT MANUAL
Duo Discus FLIGHT MANUAL
4.
4.1
Normal operatIng procedures
Introduction
Normal procedures associated with optional equipment are found in section 9.
This section provides check lists and amplifiesprocedures for conducting the daily and pre-flightinspection.
Furthermore this section inclUdes normal operatingprocedures and recommended speeds.
4.2 Rigging and de-rigging
The "Duo Discus" can be rigged by two people if awing stand or trestle is used under one wing tip.
Prior to rigging, all pins and their correspondingbearings on fuselage, wing panels and tailplaneshould be cleaned and greased.
!n~o~r~ ~i~g_p~n~l~
Unlock airbrake lever and set water ballast controlknob at "closed".
Insert the port wing panel first. It is importantthat the helper on the wing tip should concentrateon lifting the trailing edge of the wing panel morethan the leading edge, so that the rear wing attachment pin does not force the inner race of the swivelbearing on the fuselage down and out of alignment.
Check that the spar stub tip is located correctly inthe cut-out on the far side of the fuselage (if necessary, tilt the fuselage or move the wing gently up anddown to help it home).
Check that the angular levers on the wing root ribare properly inserted into their corresponding funnelson the fuselage.
Push in main wing pin approx. J cm (1.2 in.) so thatthe wing panel is prevented from sliding out by theCFRP-cover of the front wing suspension tube.The panel tip can now be placed on a wing stand.
Next insert the starboard panel the procedure isthe same as for the port wing panel. As soon as thepin on the starboard spar stub has engaged in itscorresponding bearing on the opposing wing panel(recognized by a sudden extension of the unlockedairbrakes), the starboard panel can be pushed fUllyhome under some pressure.If it is difficult/impossible to push the panel fullyhome, remove main wing pin and draw the panels together with the aid of the rigging lever (use flatside only).
Finally push main wing pin fully home and secure itshandle.
Insert spar of wing tip extension - with locking pin pushed down and ailerondeflected upwards - into the spar tunnel of the inboard wing panel.When fUlly home, the spring-loaded pin must have engaged (snapped up) inthe corresponding opening on the inboard wing panel. Make sure that thecoupling lap on the lower side of the inner aileron has correctly slid under theadjacent outer aileron.
If the locking pin has not snapped up, it has to be pushed up from the lowerside with the aid of the tailplane rigging pin.
Horizontal tailplane
Take the round-headed rigging tool (to be stored in the side-pocket) andscrew into the front tailplane locating pin on the leading edge of the fin.Thereafter slide the tailplane aft onto the two elevator actuating pins, pullrigging tool and its pin forwards, seat stabilizer nose and push locating pinhome into the front tailplane attachment fitting.
Remove rigging tool - locating pin must not protrude in front of the leadingedge of the fin.
Check whether the elevator actuating pins are really located by moving theelevator.
After rigging
Check - with the aid of a helper - the controls for full and free movement inthe correct sense.
Use tape to seal off the wing I fuselage joint and the joint between main wingpanels and their tip extension.
Caution: Do not seal off the gap between the aileron on the tip extensionand the aileron on the main wing panel.
Seal off the opening for the front tailplane attachment pin and also the jointbetween find and horizontal stabilizer (only necessary if there is no rubbersealing on the upper end of the fin).
Sealing with tape is beneficial in terms of performance and it also serves toreduce the noise level.
De-rigging
Remove sealing tape from fuselage-to-wing filletsand from the fin.
Using the threaded rigging pin, pUllout fronttailplane attachment pin, lift stabilizer leadingedge slightly and pUll tailplane forwards and off.
Push locking pin down (using the tailplane riggingpin) and carefUlly pullout tip extension.
Main wing panels---------Unlock airbrakes, set water dump valve control knobto the "closed" position and unlock handle of mainwing pin.
With a heiper on the tip of each wing panei, puiiout main wing pin up to the last 20 to JO mm (0.8 1.2 in.) and withdraw the starboard panel by gentlyrocking it backwards and forwards if necessary.
Thereafter remove main wing pin and withdraw theport wing panel.
4.3 Daily inspection e) Check for the presence of foreign objects
/®,I \I II II I
--------(1) "
When walking around the "Duo Discus", check allsurfaces for paint cracks, dents and unevenness.
In case of doubt, ask an expert for his advice.
3.0 bar (43 psi)
4.0 bar (57 psi)
Check upper and lower wing surface for damage
Check tow release mechanism(s) for propercondition and function
Clean and grease water ballast dump valves (ifnecessary)
Check that the ailerons are in good condition andoperate freely. Check for any unusual play by gently shaking the trailing edge. Check hinges fordamage
Check wing tip extensions for proper connection(locking pin must be flush with upper wing surface)
f) (reserved)
i)
a)
g) (reserved)
h) Check tire pressurel
Nose wheell
Main wheell
c)
b)
d)
o,
\I
I
/- --0--- -.... -- --@----/I
rI I
I \I \
® ",\ ~c:::=::=d ;
"--@---'
The importance of inspecting the sailplane afterrigging and before commencing the day's flyingcannot be over-emphasized, as accidents oftenoccur when these daily inspections are neglectedor carried out carelessly.
----------.......,./
II
\~~=:~=====::c..:-:::::~_
--~---------~--~
~ a) Open canopy
b) Check that the main wing pin is properlysecured
CD Check airbrakes for proper condition, fit andlocking
c) Make a visual check of all accessiblecontrol circuits in the cockpit
d) Check for full and free movements of thecontrol elements
October 199 JRevision
LBA-app.4. J. 1
October 1993Revision
LBA-app.4.3. 2
Duo Discus
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FLIGHT MANUALDuo Discus
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FLIGHT MANUAL
a) Check fuselage for damage, especially on itslower side
b) Check that the Static pressure ports for theASIan the tail boom (1.02 m/3.35 ft forward ofthe base of the fin) and below the fuselage-towing fillet are clear
a) Check condition of tail skid or wheel.If the latter is installed, check tire pressure:
3.0 bar (43 psi)
b) Should a total energy compensation probe be used,mount it and check the line (when blowing gentlyinto the probe, variometer(s) connected shouldread "climb")
c) (reserved)
d) Check that the Pitot pressure head is clear.Gently blowing into the head should produce areading on the airspeed indicator
ooo
a) Check horizontal tailplane for proper attachmentand locking
b) Check elevator and rudder for free movement
c) Check trailing edge of elevator and rudder fordamage
d) Check elevator and rudder for any unusual playby gently shaking the trailing edge
See (3)
See (2)
Reserved
After heavy landings or after the "Duo Discus" hasbeen subjected to excessive loads, the resonant wingvibration frequency should be checked (its value tobe extracted from the last inspection report for thisserial number).
Check the entire sailplane thoroughly for surfacecracks and other damage. For this purpose it shouldbe de-rigged.
Should a water ballast fin tank be installed (option):
e) Check that the fin tank spill holes are clear
Check water ballast level in fin tank (in caseof doubt, discharge ballast)
If damage is discovered (e.g. surface cracks in thefuselage tail boom or tailplane, or if delaminationis found at the wing roots or at the bearings in theroot ribs), then the sailplane must be grounded untilthe damage has been repaired by a qualified person.
g) Check that the dump hole for the fin tank in thetail wheel fairing is clear
4.5 Normal operating procedures and recommended speeds
4.4 Pre-flight inspection
Methods of launching
CHECK LIST BEFORE TAKE-OFF ONLY PERMISSIBLE WITH NOSE TOW RELEASE IN PLACE
Prior to take-off set elevator trim as followss
Maximum permitted towing speeds
180 kmlh (97 kt, 112 mph)
As the tow rope tightens, apply the wheel brake gently(by actuating the stick-mounted lever) to prevent the"Duo Discus" from overrunning the rope.
Lever forward to firstthird of its travel
Lever to the middle ofits travel
e Other clg positions
.. Rearward clg positions I
For aerotow only the nose tow release must be usedhemp and nylon ropes of between JO and 40 m length(98-1Jl ft) were tested.
e Elevator trim correctly set 7
e Canopy closed and locked ?
.. Water ballast in fin tank? (1£ 'n,talled)
.. All control surfaces checked withassistant for full and free movementin correct sense ?
.. Loading charts checked ?
.. Parachute securely fastened ?
.. Safety harness secured and tight ?
.. Seat back, head rest and pedalsin comfortable position?
.. All controls and instrumentsaccessible ?
.. Airbrakes checked and locked ?
In crosswind conditions the aileron control should beheld towards the downwind wing, i.e. in winds fromthe left the stick should be displaced to the right.This is to counteract the lift increase on the rightwing generated by the tug's prop wake, which thecrosswind forces to drift to .the right.
For intermediate to forward clg positions the elevatorshould be neutral for the ground runl in the case ofrearward clg positions it is recommended that downelevator is applied until the tail lifts.
After lift-off the elevator trim can be set for aminimum in control stick loa.ds.
Intermediate c/g positions: Lever in the middle ofits travel
Forward c/g positions•
• Rearward c/g positions
For winch launching only the c/g tow release must beused.
When flown solo, the normal towing speed is in theregion of 100 to 120 km/h (54-65 kt, 62-75 mph) and120 to 140 km/h (65-76 kt, 75-87 mph) for two occupants flying with water ballast.
Only small control surface deflections are necessaryto keep station behind the tug.
In gusty conditions or when flying into the propellerslip stream of a powerful tug, correspondingly greatercontrol stick movements are required.
The undercarriage may be retracted during the tow;this is not, however, recommended at low altitude,as changing hands on the stick could easily causethe "Duo Discus" to lose station behind the tug.
When releasing the tow rope, pUll the yellow T-shapedhandle fully several times and turn only when definitely clear of the rope.
As the cable tightens, apply the wheel brake gently(by actuating the stick-mounted lever) to prevent the"Duo Discus" from overrunning the winch cable.
Ground run and lift-off are normal there is notendency to veer-off or to climb excessively steeplyon leaving the ground.
Depending on the load on the seats, the "Duo Discus"is lifted off with the control stick slightly pushedforward in the case of aft c/g positions and slightlypulled back with the c/g in a forward position.
After climbing to a safe height, the transition intoa typical steep winch launch attitude is effected bypUlling the control stick slightly further back.
At normal all-up masses, i.e. without water ballast,the launch speed should not be less than 90 km/h (49kt, 56 mph), and with water ballast and both seatsoccupied not less than 100 to 110 km/h (54-59 kt,62-68 mph).
Normal launch speed is about 100 km/h (54 kt, 62 mph),with water ballast about 110 to 120 km/h (59-65 kt,68-7.5 mph).
February 1996Revision 4 MB J96-7 / TN J96-J
LBA-app.4.5.1.2
At the top of the launch the cable will normally backrelease automatically; the cable release handle should,nevertheless, be pulled firmly several times to ensurethat the cable has actually gone.
October 199JRevision
LBA-app.4 . .5.1.}
Duo Discus
SCHEMPP-HIRTH FLUGZEUGBAU GMBH, KIRCHHEIM/TECK
FLIGHT MANUAL Duo Discus
SCHEMPP-HIRTH FLUGZEUGBAU GMBH, KIRCHHEIM/TECK
FLIGHT MANUAL
CAUTION,
~inch launching at the maximum permitted all-up massof 700 kg (1543 lb) should only be done if there isan appropriately powerful winch and a cable in perfect condition available.
Furthermore there is not much point in launching bywinch for a soaring flight, if the release heightgained is less than 300 m (984 ft).
In case of doubt, reduce all-up mass (by dumping allwater ballast).
WInch launching with water bellast is not recommendedif the head wind is less than 20 km/h (11 kt).
WARNING' It is explicitiy advised againstwinch launching with a tail wind!
CAUTION,
Prior to launching by winch, it must be ensured thatthe crew is properly seated and able to reach allcontrol elements.
Particularly when using seat cushions it must bemade sure that during the initial acceleration andwhile in the steep climbing attitude the occupantsdo not slide backwards and up.
4.5.2 Intentionally left blank
October 1993Revision
LBA-app.4.5.1.4
October 1993Revision
LBA-app.4.5.2
Duo Discus
SCHEMPP-HIRTH FLUGZEUGBAU GMBH, KIRCHHEIM/TECK
FLIGHT MANUAL
SCHEMPP-HIRTH FLUGZEUGDAU GMBH, KIRCHHEIM/TECK
4.5.3 Flight
Duo Discus FLIGHT MANUAL
The "Duo Discus" has pleasant flight characteristicsand can be flown effortlessly at all speeds, loadingc?nditions (with or without water ballast), configurat~ons and c/g positions.
With a mid-point c/g position the maximum speed rangeCovered by the elevator trim is from about 70 km/h(38 kt, 43 mph) to about 200 km/h (108 kt, 124 mph).
Flying characteristics are pleasant and the controlsare well harmonized. Turn reversal from + 450 to _ 450is effected without any noticeable skidding. Aileronsand rUdder may be used to the limits of their travel.
At high speeds up to VNE = 250 km/h (135 kt, 155 mph)the "Duo Discus" is easily controllable.
Full deflections of control surfaces may only beapplied up to VA = 180 km/h (97 kt, 112 mph).
At V~E = 250 km/h (135 kt, 155 mph) only one third(1/)) of the full deflection range is permissible.Avoid especially sudden elevator control movements.
In strong turbulence, i.e. in wave rotors, thunderclouds, visible whirlwinds or when crossing mountainridges, the speed in rough air VRA = 180 km/h (97 kt,112 mph) must not be exceeded.
All-up mass
Speed
Reversal time
51) kg 700 kg1131 lb 154) lb
99 km/h 113 km/h53 kt 61 kt62 mph 70 mph
4.6 sec 4.6 sec
With the c/g at an aft position, the control stickmovement from the point of stall to maximum permissible speed is relatively small, though the changein speed will be noticed through a perceptiblechange in control stick loads.
The airbrakes may be extended up to VNE = 250 km/h(135 kt, 155 mph). However, they should only be usedat such high speeds in emergency or if the maximumpermitted speeds are being exceeded inadvertently.
When extending the airbrakes suddenly, the deceleration forces are noticeable.
WARNINGl
Consequently it is wise to check in advancethat the harness is tight and that the controlstick is not inadvertently thrown forwardswhen the airbrakes are extended. There shouldbe no loose objects in the cockpit.
Flights in conditions conducive to lightning strikesmust be avoided.
It should also be noted that in a dive with the airbrakes extended, the "Duo Discus" should be pulledout less abruptly than with retracted brakes (seesection 2.9 "Maneuvering load factors").
A dive with the airbrakes fUlly extended is limitedto an angle to the horizon of 300 at maximum permitted all-Up mass at a speed of 250 km/h (135 kt, 155mph) •
In order to become familiar with the -Duo Discus"it is recommended to explore its low speed and stallcharacteristics at a safe height. This should be donewhilst flying straight ahead and also whilst in a 45 0
banked turn.
A stall warning usually occurs 5 to 7 km/h ()-4 kt,)-4 mph) above stalling speed (CAS) and begins withvibration in the controls.If the stick is pUlled further back, this effect becomes more pronounced, the ailerons get spongy andthe sailplane sometimes tends to slight pitchingmotions (speed increases again and will then dropto stalling speed).
On reaching a stalled condition depending on theclg position a distinct drop of the ASI readingis observed, which then often oscillates because ofturbulent air influencing the fin-mounted Pitot tube.With the clg in rearward positions, the "Duo Discus"may slowly drop a wing, but usually it can be heldlevel.
A normal flight attitude is regained by easing thecontrol stick firmly forward and if necessaryapplying opposite rudder and aileron.
The 10s5 of height from the beginning of the stalluntil regaining a normal level flight attitude isup to )0 m (98 ft).
In the case of forward clg positions and stick fullypUlled back, the sailplane just continues to fly ina mushed condition without the nose or a wing dropping.
Normal flying attitude is regained by easing thestick forward.
When stalled during a coordinated 450 banked turn,the "Duo Discus" with the control stick pulledfUlly back just continues to fly in a stalledcondition. There is no uncontrollable tendency toenter a spin. The transition into a normal flightattitude is conducted by an appropriate use of thecontrols.
The loss of height from the beginning of the stalluntil regaining a normal level flight attitude isapprox. 20 to )0 m (66-98 ft).
Influence of water ballast
Apart from higher stall speeds caused by thehigher mass in flight water ballast in the wingtanks has no aggravating influence on the stallcharacteristics.
With water ballast in the fin tank, stall characterIstics are lIke those found for aft clg positions.
Normal approach speed with airbrakes fully extendedand wheel down is 90 km/h (49 kt, 56 mph) withoutwater ballast and flown solo, or 105 km/h (57 kt,65 mph) at maximum permitted all-up mass.
The yellow triangle on the ASI at the 100 km/h mark(54 kt, 62 mph) is the recommended approach speedfor the maximum all-up mass without water ballast(660 kg/1455 lb).
In the above configurations the L/D is approximately 6.7 I 1-
The airbrakes open smoothly and are an effectivelanding aid.
Side slipping is also a fine aid for landing. It ispossible in a straight line with the rudder deflected up to 85 ~ of its travel and results in a yawangle of about 400 and a bank angle of about 25 toJOo • The control force reversal perceptible is low.
To return to level flight, normal opposite controlsare required.
Qa!!.t.!.O!!.1
With rudder fUlly deflected, side slips in a straightflight path are not possible the sailplane willslowly turn in the direction of the displaced rudder.
WARNING I
Both the performance and the aerodynamic characteristics of the "Duo Discus" are affected adverselyby heavy rain or ice on the wing. Be cautious whenlanding!Increase the approach speed by at least 5 to 10km/h (3-5 kt, 3-6 mph).
Landing
For off-field landings the undercarriage shouldalways be extended, as the protection of the crewis much better, especially from vertical impactson landing.
Main wheel and tail wheel should touch down simultaneously.
To avoid a long ground run, make sUre that the sailplane touches down at minimum speed.A touch-down at a speed of 90 km/h (49 kt, 56 mph)instead of 70 km/h (38 kt, 4J mph) means that thekinetic energy to be dissipated by braking i8 increased by a factor of 1.65 and therefore the gr?undrun is lengthened considerably.
The hydraulic main wheel disc brake is actuated viathe airbrake linkage with airbrakes almost fUlly extended.
As the effectiveness of the wheel brake is good, thelanding run is considerably shortened (the elevatorcontrol should be kept fUlly back).
October 1993Revision
LBA-app.4.5.4
October 1993Revision
LBA-app.4.5.5
Duo Discus
SCHEMPP-HIRTH FLUGZEUGBAU GMBH, KIRCHHEIM/TECK
FLIGHT MANUALDuo Discus
SCHEMPP-HIRTH FLUGZEUGBAU GMBH, KIRCHHEIM/TECK
FLIGHT MANUAL
4.5.6 Flight with water ballast
If the maximum permitted all-up mass is to be reached,then water ballast is required.
The water tanks are integral compartments in the nosesection of the main wing panels.These tanks are to be filled with clear water only,through round openings in the upper wing surfacefeaturing a strainer.
Tank openings are closed with plugged-in filler capshaving a 6 mm (0.24 in.) female thread for liftingand venting. Lifting these caps is done with the aidof the tailplane rigging pin.
WARNINGs
As the threaded hole in the filler cap also servesfor venting the tank, it~ always be kept open!
Dumping the water from full tanks takes about five(5) minutes.
Each tank has a capacity of 99 Liter (26.15 us Gal.,21.78 IMP Gal.).
When filling the tanks it must be ensured that themaximum permitted all-up mass is not exceededsee page 6.2.5.
The tank on either side must always be filled withthe same amount of water to prevent lateral imbalance.
When taking off with partly full tanks, ensure thatthe wings are held level to allow the water to beequally distributed so that the wings are balanced.
Because of the additional mass in the wing panels,the wing tip runner should continue running for aslong as possible during the launch.
Water ballast is dumped through an opening on thelower side of the main wing panels, 1.93 m (6.33 ft)away from the root rib.
The dump valves are hooked up automatically on riggingthe sailplane (with water ballast control knob to beset at "CLOSED").
Thanks to baffles inside the ballast tanks there is noperceptible movement of the water ballast when flyingwith partly filled tanks.
When flying at maximum permitted all-up mass, the lowspeed and stall behaviour of the "Duo Discus" isslightly different from its flight characteristicswithout water ballastl The stall speeds are higher(see section 5.2.2) and for correcting the flIghtattitude larger control surface deflections are reqUired. Furthermore more height is lost until anormal flight attitude is regained.
WARNINGs
In the unlikely event of the tanks emptying unevenlyor only one of them emptying (recognized by havingto apply up to 50 ~ opposite aileron for a normalflight attitUde), it is necessary to fly somewhatfaster to take into account the higher mass andalso to avoid stalling the sailplane.
During the landing run the heavier wing should bekept somewhat higher (if permitted by the terrain)so that it touches down only at the lowest possiblespeed. This reduces the danger of the "Duo Discus"to veer off course.
October 199JRevision
LBA-app.4.5.6.1
October 199JRevision
LBA-app.4.5.6.2
SCHEMPP-HIRTH FLUGZEUGBAU GMBH, KIRCHHEIM/TECK
iscus
Water ballast fin tank (optional)
Tank label on the right hand side of the fin
FLIGHT MANUAL
For optimum performance in circling flight, the forwardtravel of the center of gravity, caused by water ballastin the wing nose and by the crew member on the aft seat,may be compensated by carrying water ballast in the fintank.
For details concerning the quantities to be filled referto page 6.2.8.
The water ballast tank is an integral compartment in thefin with a capacity of 11.0 kg/Liter (2.91 US Gal., 2.42IMP Gal.). This tank is filled as follows with thehorizontal tailplane in place or removed:
Insert one end of a flexible plastic hose (outer diameter8.0 mm/O.)l in.) into the tube (internal diameter 10.0 mm/0.)9 in.) protruding from the rudder gap at the top ofthe fin on the left hand side. The other end of this hoseis then connected to a suitable container which is to befilled with the required amount of clear water.
The fin tank has eleven (11) spill holes, all properlymarked, on the right hand side of the fin, which indicatethe water level see accompanying sketch.
The venting of the tank is through the uppermost 11 kg/Liter hole (which always remains open even with afull tank).
The ballast quantity to be filled, depends on the waterload in the wing tanks and/or on the load on the aftseat see loading tables on page 6.2.8.
Always tape closed one hole less than the load required,measured in kg/Liter.
If, for instance, a fin ballast load of ).0 kg/Liter isrequired, only the lower two holes (1 and 2) are tapedclosed, any excessive water then escapes through thethird spill hole, thus preventing any overloading.
•ber 199).sion
II " k9/Ltr •
II ,0
II 9
II BII '7II 6II 5
4II :5
.2II ,
LBA-app •4.5.6.)
)uo Discus
SCHEMPP-HIRTH FLUGZEUGBAU GMBH. KIRCHHEIM/TECK
FLIGHT MANUAL Duo Discus
SCHEMPP-HIRTH FLUGZEUGBAU GMBH, KIRCHHEIM/TECK
FLIGHT MANUAL
Water is dumped from the fin tank through an openingon the lower side of the fuselage tail boom ad-jacent to the rudder.
The fin tank dump valve is linked to the torsionaldrive for the valves on the main wing panels 50 thatthese three tanks are always emptying simultaneously.
The time required to dump the ballast from a fullfin tank is about two (2) minutes, i.e. drainingthe full tanks of the main wing panels alwaystakes longer.
ctd. on page 4.5.6.5
G ENE R A L
WARNING I
1. On longer flights at air temperatures near 0 0 C(320 F), water ballast must be dumped in any casewhen reaching a temperature of 2 0 C (360 F).
2. There is little point in loading much water ballastif the average rate of climb expected does not exceed 1.0 m/s (197 fpm). The same applies to flightsin narrow thermals requiring steep angles of bank.
3. If possible, all water ballast should be dumpedbefore conducting an off-field landing.
4. Before the wing water tanks are filled, it shouldbe checked (with dump valves unlocked) that bothdrain plugs open up equally. Leaking (dripping)valves are avoided by cleaning and greasing theplugs and their seats (With valves opened).Thereafter, with valves closed, the drain plugsare pulled home with the threaded tool used toattach the horizontal tailplane.
WARNING I
5. Never pressurize the tanks for instance byfilling them directly from a water hose andalways pour in clear water only.
6. On no account whatsoever must the "Duo Discus"ever be parked with full ballast tanks if thereis the danger of them freezing up.Even in normal temperatures the parking periodwith full tanks should not exceed several days.For parking all water ballast is to be completelydrained off with filler caps removed to allow thetanks to dry out.
7. Before the fin tank is filled, check that thosespill holes not being taped closed are clear.
When flying at high altitude it should be noted thattrue airspeed (TAS) increases versus indicated airspeed (IAS). This difference does not affect thestructural integrity or load factors, but to avoidany risk of flutter, the following indicated values(IAS) must not be exceeded
When flying at temperatures below 00 C (320 F), as inwave or during the winter months, it is possible thatthe usual ease and smoothness of the control circuitsis reduced.It must therefore be ensured that all control elementsare free from moisture so that there is no danger ofthem freezing solid. This applies especially to theairbrakesl
From experience gained to date it has been found beneficial to cover the mating surfaces of the airbrakeswith "Vaseline" along their full length so that theycannot freeze solid. Furthermore the control surfacesshould be moved frequently.
When flying with water ballast observe the instructions given in section 4.5.6.
Note:
The polyester coating on this sailplane is knownfrom many years experience to become very brittleat low temperature.
Particularly when flying in wave at altitudes inexcess of about 6000 m (approx. 20000 ft), wheretemperatures of below _)00 C (_220 F) may occur,the gel-coat, depending on its thickness and thestressing of the sailplane's components, is proneto crackingl
Initially, cracks will only appear in the polyestercoating, however, with time and changing environment, cracks can reach the Epoxy/glass matrix.
Cracking is obviously enhanced by steep descentsfrom high altitudes at associated very low temperatures.
WARNING:
Therefore, for the preservation of a propersurface finish free from cracking, the manufacturer strongly advises against high altitude flights with associated temperatures ofclearly below _200 C (_4 0 F)!
A steep descent with the airbrakes extendedshould only be conducted in case of emergency(instead of the airbrakes, the undercarriagemay also be extended to increase the rate ofsink) .
When flying the "Duo Discus" with a wet surface orin rain, the size of the water drops adhering tothe wing causes a deterioration of its flightperformance which cannot be expressed in numericalvalues due to the difficulties involved with suchmeasurements. Often the air mass containing themoisture is also descending so that comparedwith a wet sailplane in calm air the sinkrates encountered are higher.
Flight tests in rain, conducted by the manufacturer,did not reveal any significant differences in thestalling behaviour or stalling speeds.
It cannot be excluded, however, that excessivealterations of the airfoil (as caused by snow,ice or heavy rain) result in higher minimumspeeds.
Weight (mass) and balance recordand permitted payload range.
Determination ofl
• Water ballast in wing tanks
• Water ballast in fin tank
6.1 Introduction
This section contains the seat load range withinwhich the "Duo Discus" may be safely operated.
Procedures for weighing the sailplane and thecalculation method for establishing the permitted payload range and a comprehensive list ofall equipment available are contained in the"Duo Discus" Maintenance Manual.
The equipment actually installed during the lastweighing of the sailplane is shown in the "Equipment List" to which page 6.2.3 refers to.
October 1993Revision 6.1.1
October 1993Revision 6.1.2
Duo Discus
SCHEMPP-HIRTH FLUGZEUGBAU GMBH, KIRCHHEIM/TECK
FLIGHT MANAL Duo Discus
SCHEMPP-HIRTH FLUGZEUGBAU GMBH, KIRCHHEIM/TECK
FLIGHT MANUAL
6.2 Weight and balance record / Permitted payload range
The following weight and balance log sheet (page 6.2.J)shows the maximum and minimum load on the seats. It isestablished with the aid of the last valid weighingreport the required data and diagrams are foundin the "Duo Discus" Maintenance Manual.
The weight and balance log sheet is only applicablefor this particular sailplane, the serial number ofwhich is shown on the title page.
1. By attaching ballast (lead or sand cushion)firmly to the lap belt mounting brackets.
Optional trim ballast mounting provision(s)
Altering the front seat load by trim ballast
On request the "Duo Discus" is equipped with oneor two mounting provisions for trim ballast, thusallowing a reduction of the placarded minimum frontseat load (when flown soJo) as shown in the tablebelow.
a) Trim ballast mounting provision~ frontinstrument panel:
This tray holds up to three (J) lead plateswith a weight of J.7 kg/8.2 lb each. Platesare made to fit only into this tray.
Lever arm of trim ballast plates:
2055 moo (6.74 ft) ahead of datum
2. a) By installing ballast (by means of lead plates)at the base of the front instrument p'anel(for further information refer to page 6.2.2)
b) Trim ballast mounting provision on front stickmounting frame on the starboard side:
This tray holds up to three (3) lead plateswith a weight of 3.9 kg/8.6 Ib each. Platesare made to fit only into this tray.
b) By attaching ballast (in addition to method 2 a)by means of lead plates to the front controlstick mounting frame on the starboard side nearthe base of the instrument panel(for further information refer to page 6.2.2).
Lever arm of trim ballast plates:
1855 moo (6.09 ft) ahead of datum
WHEN FLOWN SOLO: Difference Number ofin seat load as compared with lead platesplacarded front seat minimum: required:
up to 5 kg ( 1 1 Ib) less ~ 1<1l
up to 10 kg (22 lb) less 4> 2
(3J lb)4>
up to 15 kg less III 3
up to 20 kg ( 44 lb) less ~ 4.0
up to 25 kg (55 lb) less 4> 5
(66 lb)4>
6up to JO kg less III
)ctober 1993~evision 6.2.1
October 1993Revision 6.2.2
SCHEMPP-HIRTH FLUGZEUGBAU GMBH, KIRCHHEIM I TECK
DuoDiscus FLIGHT MANUAL
WEIGHT AND BALANCE LOG SHEET ( loading chart )
for Serial-No, 414
Date of weighing 07.04.04
Empty mass ( kg ) 422,7
Equipment list dated 07.04.04
Empty mass c I g position 523,4
aft of datum ( mm )
Max. useful load ( kg ) in 220,7
fuselage incl. Ballast in fin tank
Load ( kg ) on the seats ( crew including rarachutes ):
Maximum front seat load
when flown solo 110,0 110 110 110
with two occupants 110,0
Maximum rear seat load 110,0
Water ballast fin tank YES
installed ( YES I NO )
Minimum front seat load
regadless off load on
rear seat with
a) Fin tank NOT installed
b) Fin tank installed *)
Inspector
Signature
Stamp
Note
*) 1 For safety reasons the value determind by weighing with an empty fin tank
has been increased by 30 kg ( 66 Ib ) so as to allow for an unnoticed filled
fin tank,
2. Adding the mass of 30 kg ( 66 Ib ) is not required, however, if the pilot either
dumps ill! water ballast ( prior to take-off) or does ensure that the ballast
quantity in the fin tank is compensated by an appropriate load in the wing tanks
and lor on the aft seat.
For the determination of water ballast quantity permitted in the wing tanks
refer to page 6.2S
For the determination of water ballast quantity permitted in the fin tank refer to
page 626 through 628.
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FLIGHT MANUAL
INTENTIONALLY LEFT BLANK
October 1993Revision - 6,2.3
October 1993Revision 6.2.4
klauder
Text Box
04-04-2010 Serial # 414 Empty Weight 934 Lbs CG 20.6" aft of Datum
SCHEMPP-HIRTH FLUGZEUGBAU GMBH, KIRCHHEIM/TECK
Duo Discus
Maximum water ballast load
Maximum all-up mass including water ballast
c/G position of water ballast in wing tanks z
FLIGHT MANUAL
700 kg (1543 lb)
65 mm (2.56 in.) aft of datum plane
lio!e~ When determining the maximum permitted wing water ballast load, allowance must bemade for water ballast in the fin tank (see page 6.2.7 and 6.2.8), i.e. this loadmust be added to the empty mass shown in the table bel~w (if tank is used).
Empty mass * = Empty mass as per page 6.2.3 + ballast in fin tank
Tank capacity of both wing tanks: 198 kg/liter (5 2 .3 1 US Gal., 43.56 IMP Gal.)
Table of water ballast loads at various empty masses and seat loadsz
Empty T 0 t a 1 1 0 a d o n t h e B e a t 5 (kg / Ib)
mass if- kg Ib kg Ib kg Ib kg Ib kg Ib kg Ib kg Ib kg Ib kg Ibkg Ib 70 154 80 176 100 220 120 265 140 309 160 353 180 397 200 441 220 485
III III III III III III III III III til III III m III III m III III III III III III III III m co III... l;) l;) ... l;) l;) ... l;) l;) ... l;) t:I ... l;) t:I ... t:I t:I +> t:I l;) *' t.:l t:I ... l;) t.:l..-I ..-I ..; ..; .... ..; .... .... ........J U1 a. ....J U1 0. ....J U1 0. ....J U1 0. ....J U1 0. ....J U1 0. ....J U1 0. ....J U1 a. ....J U1 a.
In order to shift the center of gravity close to itsaft limit (favourable in terms of performance),water ballast may be carried in the fin tank (mFT )to compensate for the nose-heavy moment of
o water ballast in main wing panels (m WT )
and/or
• loads on the aft seat (mp2 )
When determining the water ballast quantity for thefin tank, bear in mind that the maximum permittedusefUl load in the fuselage (see page 6.2.) "Weightand balance log sheet") must not be exceededcheck as foilowsl
load on front seat
load on aft seat
£o~p~n~a!i~g_w~t~r_b~l~a~t_i~~a~n_w~n! ~a~e~s_
The determination of the ballast quantity in the fintank (mFT) is done with the aid of the diagram shownon page 6.2.8.
=
ballast in fin tank (to compensate forballast in wing tanks)
ballast in fin tank (to compensate forloads on the aft seat)
Pilots wishing to fly with the center of gravity closeto the aft limit, may compensate the nose-heavy momentof loads on the pft seat with the aid of the diagramshown on page 6.2.8.
= less or equal to maximumuseful load in fuselage(see also page 6.2.3)
~I When using fin ballast to compensate for thenose-heavy moment of wing ballast and loads onthe aft seat, then both values resulting fromthe diagrams on page 6.2.8 must be taken intoaccount.
The maximum amount of water ballast, availablefor compensating the above mentioned nose-heavymoments, is 11 liter (2.91 US Gal., 2.42 IMP Gal),which is the maximum capacity of the fin tank.
WARNING:
A compensation of masses exceeding the placardedminimum front seat load is not allowed!
In order to avoid that the maximum permitted all-upmass is exceeded, the ballast in the fin tank mustalso be taken into account when determining the maximum allowable ballast quantity for the wing tanks.
All instruments and control elements are within easyreach or the crew.
Duo Discus
o
FLIGHT MANUAL
Instrument panels
With canopy opened, the instruments roreither seat are easily accessible.
The rront instrument panel is attached to thecanopy coaming frame on the fuselage and tothe control stick mounting rrame.
The rear panel is mounted to the steel transverse frame between the seats.
Both instrument panels and their covers areeasily detached after removing the mountingbolts.
Tow release handles
Duo Discus FLIGHT MANUAL
Rudder pedal adjustment (front seat)
Black T-shaped handle on the right near thebase or the control stick.
Forward adjustment: Release locking device bypulling the handle, pushpedals to desired positionwith the heels and letthem engage.
Backward adjustment: Pull handle back untilpedals have reacheddesired position.Forward pressure vithheels (not the toes)engages pedals innearest notch vith anaudible click.
An adjustment or the rudder pedals is possibleon the ground and in the air.
Rudder pedal adjustment (rear seat)
Locking device on pedal mounting structure oncockpit floor.
T-shaped handles, actuating the tow release(s)installed (c/g and/or nose hook)
Er~n! seat: Yellow handle at the base of thecontrol stick on the left
Re~r_s~a! Yellow handle on the lower lefthand side of the instrument panel
The winch cable/aero tow rope is released bypulling one or the handles.
Forward or backwardadjustment : Pull up locking pin by its
ring, slide pedal assemblyto desired forward or backward position and pushlocking pin down intonearest recess.
October 1993Revision October 1993
Revision
An adjustment or the rudder pedals is possibleon the ground and In the air.
7.2·3
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FLIGHT MANUAL
Ventilation Elevator trim
Green knob (for either seat) at the seat pan mountingflange on the left.
The spring-operated elevator trim is gradually adjustable by swinging the green knob slightly inwards,sliding it to the desired position and swinging itoutwards to lock.
Black knob in the middle of the GFRP inner skin onthe right.
Small black knob on the front instrument panel on theleft.
Pul I to close ventilator
Push to open ventilator
Additionally the clear vision panels or the airscoopin the panels may be opened for ventilation.
'Wheel brake
A wheel brake handle is mounted on either controlstick.AdditLonally the wheel brake can be actuated by extending the alrbrakes fully.
Airbrake lever
Forward position
Backward position
Control knob for dumfrom win tanks and
Backward position
Forward position
nose-heavy
tail-heavy
ballastfin tank
dump valves closed
dump valves open
Levers (with blue marking), projecting downwards,below the GFRP inner skin on the left.
The operating knob is locked in the extreme positionsby swinging it downwards into a recess.
Forward position
Pulled back aboutq0 mm (1. 6 in.)
Pulled fUlly back
Head rests
Airbrakes closed and locked
Airbrakes unlocked
Alrbrakes fUlly extended andwheel brake actuated
The fin tank dump valve control is connected to thetorque tube actuating the valves on the wing so thatall three valves open and close simultaneouely.
Seat back (front seat)
Sliding black grip on the GFRP inner skin on theright.
Front seat
Rear seat (notillustrated)
October 1993Revision
Head rest (vertically adjustable)on canopy transverse frame
Mounting rail below upper fuselage skin. Head reet is graduallyand horizontally adjustablelDepress locking tap, elide headrest in desired position and letlocking tap engage into nearestrecess
7.2. 11
Adjustment
October 1993Revision
Tilt front end of grip slightly inwards, slide grip to desired positionand let engage by tilting it outwards.
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FLIGHT MANUAL
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FLIGHT MANUAL
Rip cord anchorage
Front seat
Rear seat
Canopy
Red steel ring on tubular framebetween the seats on the left
Red steel ring at the front ofthe steel tube center frame onthe left
Canopy release
Black lever (for rear seat) on the GFRP inner skinon the right.
lio~eL Up to siN 10 this lever is also provided forthe front seat.
To remove the canopy, proceed as follows:
Remove pin securing the canopy release lever, swingback the latter and the locking lever, disconnectrestraining cable and lift off the canopy.
The one-piece plexiglass canopy hinges sideways onflush fittings.
Take care that the cable restraining the open canopyis properly hooked up.
Canopy locking and jettisoning levers
Lever with red grip for either seat on the canopyframe on the left.
Undercarriage
Retracting: Disengage black handle below the GFRPinner skin on the right, pull it backand lock in rear recess
Extending: Disengage handle, push it forward andlock in front recess
Forward position J Canopy locked
To open or jettison the canopy, swing one of thelevers back (beyond 900 ) and raise canopy.
Black handle below the GFRP inner skin on the right.
This handle is provided to assist in operating theundercarrioKe. It also indicates whether the wheelis up or dOWJl.
The handle cannot be used, however, to lock the u/c.
October 1993Revision 7.2.6 october 1993
Revision 7·2.7
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FLIGHT MANUAL Duo Discus
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FLIGHT MANUAL
.) Instrument panels
Master switch
Panel-mounted nON/OFF" switch (f'or f'ront seat).
UP
DOWN
ON
OFF
For a description of' components No. 0 through Gref'er to page 7.).2. ~
A description of' the instrumentation and an illustrationof' the rear instrument panel is not deemed necessary.
Pneumatic valve
Inapplicable
Outside air temperature indicator
lctober 199)tevision 7.).1
February 1996Revision 4 MB )96-7 / TN )96-) 7. ).2
The main wheel of the "Duo Discus" is retractableand features a hydraulic disc brake. A small wheelis provided on the lower side of the forward fuselage section and protects the latter from damage.Instead of the standard rubber tail skid a nonsteerable pneumatic wheel is available on request.
The extension/retraction process of the main wheelis described on page 7.2.4 ("cockpit description"),the operation of the main wheel brake is given onpage 7.2.2 and 7.2.5.
For a technical description of the retractableundercarriage including its wheel brake systemsee also page 1.2.5 of the "Duo Discus" Maintenance Manual.
7.5 Seats and restraint systems
The seat pans are bolted to mounting flanges providedon either side of the cockpit.
The front seat features a back rest, adjustable inflight see also page 7.2.5 concerning the procedurefor its adjustment.
For either seat the lap straps are anchored to the seatpan.
While the shoulder straps for the front seat areanchored to the steel tube transverse frame, thosefor the rear seat are attached to the steel tubecenter frame.
A list of approved restraint systems is provided inchapter 7.1 of the "Duo Discus" Maintenance Manual.
Static pressure and Pitot pressure system7.7 Airbrake system
a) Static pressure ports are on either side of thefuselage tail boom, 1.02 m / 40.16 in. forward ofthe base of the fin (in the horizontal plane)and 0.18 m / 7.09 in. below the fuselage/wingfillet, to be used for ASI etc.
Schempp-Hirth type airbrakes are employed on theupper surface of the main wing panels.
A schematic view of the airbrake system is givenin the Maintenance Manual.
b) On request a special static pressure probe can beinstalled near the top of the fin (for furtherinstruments, except ASI).
c) On request additional static pressure sources canbe provided on either side of the fuselage skinnear the front instrument panel.
The Pitot pressure head is situated near the upperend of the fin.
Soft objects (like jackets etc.), however, may bedeposited on the removable panel (covering thecontrol linkages) behind the main spar stubs.
Such items, however, must be taken into accountwhen determining the permissible load on theseats.
7.9 Water ballast system(s)
A steel cable connects the operating knob in thecockpit to a torque tube actuating the wing tankdump valves and via a further steel cablethe dump valve of the (optional) fin tank seepage 7.9.3.
On rigging the main wing panels, the torque tubein the fuselage is automatically hooked up to thetorsional drive of the dump valve plugs.
The torque tube is rotated to the "closed" posi-tion by spring force see page 7.9.2.
The operating knob in the cockpit is run in agate and can be locked in its extreme positions.
Ootober 1993Revision 7.8 October 1993
Revision
WATER BALLAST SYSTEM
SCHEMPP-HIRTH FLUGZEUGBAU GmbH., KIRCHHEIMITECK
Duo Discus
.... _--..""."'"
October 1993Revision --
2.
strainer
1.
1.
2.
FLIGHT MANUAL
Water tank filler opening on main wing panelswith strainer and vent hole in filler cap.Dump valve control for wing tanksand fin tank.
7.9.2
SCHEMPP-HIRTH FLUGZEUGBAU GMBH, KIRCHHEIM/TECK
Duo Discus
FLIGHT MANUAL
1. Dump valve control for tank inmain wing panels
2. Torque tube3. Dump valve control for fin tank4. Dump valve5. Vent holes6. Filler opening7. Dump hole8. Spill holes
The wiring of the gliding avionics is shown on thenext page and must comply with the manufacturer'sinstructions for the relevant equipment.
Power to operate the avionics is provided by one ormore batteries located forward of the rear controlstick mounting frame or next to the fuselage steeltube center frame.
A mounting provision for removable ballast (trimballast weights) is provided at the base of thefront instrument panel.
A second ballast mounting provision is found onthe right hand side of the front stick mountingframe.
The trim ballast weights (lead plates) are to besecured in place by bolts.
For information on how to alter the minimum frontseat load refer to section 6.2.
Attachment points for the mounting brackets of oxygenbottles are provided on the rear wing suspension tube(for the neck) and further aft on the horizontal GFRPreinforcement (for the cylinder).
For the installation of oxygen systems, drawingsmay be obtained from the manufacturer.
~ After oxygen systems are installed, it isnecessary to re-establish the empty massc/g position of the "DuO Discus" concernedto ensure that the center of gravity isstill within the permitted range.
A list of oxygen regulators, currently approved bythe Luftfahrt Bundesamt (LBA), is found in the"Duo Discus" Maintenance Manual.
ELT-installation
The installation of an Emergency Locator Transmitteris possible in the following places and must complywith the instructions provided by Schempp-Hirths
In the region of the rear seaton either seat pan mounting flange
This section contClins manufacturer'e recommendedprocedures for proper ground handling and servicingof the sailplane.
It also identifies certain inspection and maintenance requirements which must be followed if thesailplane is to retain that "new plane" performanceand dependability.
8.2 Sailplane inspection periods
8.3
8.4
Sailplane alterations or repairs
Ground handling / road transport
It is wise to follow a planned schedule oflubrication and preventative maintenancebased on climate and flying conditions en-countered see section 3.2 of the "DuoDiscus" Maintenance Manual.
8.5 Cleaning and care
october 1993Revision 8.1.1 October 1993
Revision 8.1. 2
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which doesbeing re-
sailplane inspection periods
For details concerning the maintenance of this sailplanerefer to its Maintenance Manual.
Airframe maintenance
Under normal operating conditions no airframe maintenance work is required between the annual surveys, except for the routine greasing of the spigots and ballbearings of the wing and tailplane attachment fittings.
Should the control system become heavy to operate,lubricate those places in the fuselage and in thewing panels where plain bearings are used (e.g. airbrake linkage).
Cleaning and greasing the wheels and the tow release(s)depends on the accumulation of dirt.
Rudder cables
After every 200 flying hours and at every annualsurvey, the rudder cables are to be inspected atthe point where they feed through the S-shapedguides in the pedals, especially at the point ofmaximum pedal adjustment.
If the rudder cables are damaged, worn or corroded,they must be replaced.
It is permissible for individual strands of thecables to be worn up to 25 ~.
8.) Sailplane alterations or repairs
Alterations on the approved model, which might affectits airworthiness, must be reported to the responsibleairworthiness authorities p rio r to their accomplishment.
The authorities will then determine whether and towhat extent a "supplemental type approval" is to beconducted.
In any case, the manufacturer's opinion about thealteration(s) must be obtained.
This ensures that the airworthiness does not becomeadversely affected and/or enables the aircraft owner/operator to demonstrate at any time that the sailplaneconcerned complies with an LBA-approved version.
Amendments of the LBA-approved sections of the Flightand/or Maintenance Manual must in any case be approvedby the Luftfahrt Bundesamt (LBA).
Before every take-off and especially after the aircrafthas not been used for a while, it should be checked onthe ground as shown in section 4.).Check for any sign of a change in the condition of theaircraft, such as cracks in the surface, holes, delamination in the CFRP/GFRP structure etc.
If there is any uncertainty whatsoever regarding thesignificance of damage discovered, the "Duo Discus"should always be inspected by a CFRP/GFRP expert.
There is no objection to minor damagenot affect the airworthiness in any waypaired on site.A definition of such damage is included in the "RepairInstructions" which are found in the appendix to the"Duo Discus" Maintenance Manual.
Major repairs may only be conducted by a certifiedrepair station having an appropriate authorization.
When towing the "Duo Discus" behind a car, a taildolly should always be used to avoid unnecessarytailplane vibration on the fittings especial-ly in tight turns.When pushing the sailplane by hand, it should notbe pushed at its wing tips, but as near to thefuselage as posslblo.
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The "Duo Discus" should always be hangared or keptin well ventilated conditions. If it is kept in aclosed trailer, there must be adequate ventilation.
The water ballast tanks must always be left completely empty.
The sailplane must never by subjected to loadswhilst not in use, especially in the case ofhigh ambient temperatur.es.
In the case of a "Duo Discus" remaining riggedpermanently, it i6 important that the maintenanceprogram includes rust prevention for the fittingson fuselage, wings and tailplane.
Tie-down kits common in trade may be used toanchor the sailplane.
Dust covers should be regarded as essential forthe "Duo Discus".
As the wings have a thin airfoil section, it isimportant that they are properly supported, i.e.leading edge down, with support at the spar stubsand at the outer portion in cradles of correctairfoil section.The fuselage can rest on a broad cradle just forward of the u/c doors and on its tail wheel/skid.The horizontal tailplane shOUld be kept leadingedge down in two cradles of correct airfoil section or placed horizontally on a padded support.
On no account should the tailplane be supportedby its fittings in the trailer.
Cleaning and care
Although the surface coating of a composite sailplaneis robust and resistent, always take care of a perfectsurface.
For cleaning and caring the following is recommended I
• Clean the surface (especially the leading edge ofthe wings, horizontal stabilizer and fin) withclear water, a spongue and a chamois leather.
• Do not use too often rinsing additives common intrade.
• Polish and polishing materials may be used.
• Petrol and alcohol may be used momentarily only,thinners of all kinds are not recommended.
• Never use chlorine hydrogen (i.e. Tri, Tetra, Peretc. ).
e The beat polIshing method La the buffing of thesurface by means of an edge buffing wheel, fittedto a drilling or polishing machine.
Thereby hard wax is applied to the rotating discand distributed crosswise over the surface.
WARNINGsTo avoid a local overheating, the bUffing wheelshould be moved constantly!
• The canopy should be cleaned with a plexiglasscleaner (e.g. "Plexiklar", "Mirror Glaze" orsimilar) and only if necessary, with warm water.
The canopy should be wiped down only with a softclean chamois leather or a very soft material asused for gloves.
Never rub the canopy when it is dry!
.. The "Duo Discus" should always be protected fromthe wet. If water has found a way in, the components should be stored in a dry environment andturned frequently to eliminate the water.
The "Duo Discus" should not be exposed unnecessarily to intense sunlight or heat and shouldnot be subjected to continual loads in a mechanical sense.
WARNINGI
All external portions of the sailplane exposedto sunlight must be painted white with theexception of the areas for the registrationand anti-collision markings.
Colours other than white can lead to the GFRP/CFRP overheating in direct sunlight, reSUltingin an insufficient strength.
This section contains the appropriate supplementsnecessary to safely and efficiently operate thesailplane when equipped with various optionalsystems and equipment not provided with thestandard aircraft.