Grob TWIN-ASTIR User manual

GROB
GROB-FLUGZEUGBAU
8939 Mattsfes
Flugplatz Mlndelhelm-Mattsies
Telefon
08268/411
FLIGHT HANDBOOK
-,- ""-' I IV - 1-~J:::':I} • , I
11?
This handbook must be carried on board at atl times.
Jt refers to the TWIN ASTIR Sailplane
Registration: Factory Serial Number:
Owner:
German edition
of operating instructions are approved under § 12/2.
of LuftGerPO.
Published
Approval of translation has been done by beat knowledge and judgement -In any case the
original text In German language Is authoritative.
N8485W
3250
Utah Soaring Association

· GROB
GRO~-FLUGZEUGBAU
8939 Matts!es
FJugplatz Mindelheim-Mattsies
Terefon 08268/411
FLI"GHT HANDBOOK
-.--~I I'J -I I .!*S·
TRAINER • I
.......... <~1
ThJs handbook must be carried on board at all times.
lt refers to the TWIN-ASTIR TRAINER Sailplane
Registration:
Factory Serial Number:
Owner:
German edition of operating instructions are approved under § 12/2.
of LuftGerPO.
Pub fished
Approval of translation has been done by beat knowledge and judgement -In any caea the
original text
In German languag& Is authoritative.

FLIGHT HANDBOOK TW~N ASTIR 1
Updates
Current Page Reference Date
Signature
LBA-
number
Approval
1 Sa TWIN ASTIRTRAINER 1.4.78·
2 17 New Control Levers 1.10.78
\
3 18 New Control Levers 1.10.78
4 25 Check of wing 1.10.78
5 25a Fittings 1.10.78
6 1, 28 Service Butletin 28.09.92
315-50
7
1,25,25a
TM 315-58 04.11.96
8 1,
7, 1"1
As ·a315-64 30.06.2003
Envelope Limitations
-
MSB 315-64/3
~ /
t(_~
1
2. DKr. 2aa~
9 1, 7,
11
Revised Limits of
14.09.2004
f2\
Operation
/.~~ _..
~ t- ..- ·
~
14 September 2004

FLIGHT HANDBOOK TWIN ASTIR 2
Contents
I. General
I. 1 Updates 1
I. 2 Contents 2
1 •. 3 Photograph 4
I. 4 Drawing 5
I. 5 Description 6
11. Operating limits
ll. 1 Airworthiness Group 6
11. 2 Permitted operating conditions 6
11. 3 Minimum equipment 6
11.
4 Maximum Speeds 7
11. 5 Flight envelope 7
11.
6 Weight limits 8
11.
7 Centre of gravity position 8
11. 8 Load scheme 8
11.
9 Tow hooks 10
11. 10
Weak link strength 10
11. 11
Tire pressure 10
11. 12
Cros:swlnds 10
11.
13 Required placards
11
11. 14
Symbols 13
Ill. Emergency procedures
Ill. 1 Exit from a spin
15
Ill. 2 Emergency canopy jettisoning and exit 15
Ill. 3 Landing with a retracted undercarriage 15
Ill. 4 Others (Rain, ice, stall, groundloops} 15
Ill. 5 Instruments specifications 16

FLIGHT HANDBOOK TWIN ASTIR 3
IV . Normal operation
IV.
1 Cockpit and controls (Picture) 17
IV.
2 Daily preflight inspection 19
IV· 3 Control checks before
take off 21
IV.
4 Take off
21
IV. 5 Free Flight
22
IV. 6 Slow flying and stalls 22
IV. 7 High speed flight 22
IV .. 8 Cloud flying 22
IV.
9 Simpre Aerobatics
23
IV. 10 Approach and landing
24
IV. 11 Flying with waterballast
24
V. Rigging and derigging
V. 1 Rigging, derigging
25
V.
2 Storage 26
V. 3 Transport
27
V. 4 · Ma intenance of the glider
27
VI. Appendices
VI. 1 Flight performance
29
VI. 2 Service and Maintenance instructions 30
VI. 3 ·_ Reference to repairs
31
Vl. 4 - Reference
to release hooks 31
VI. 5 Determination
of the center of gravity
31

FLIGHT HANDBOOK TWIN ASTIR 5
I
'

FLIGHT HANDBOOK TWIN ASTIR
5a
The sailplane TWIN-ASTIR TRAINER is derived from the TWIN-ASTIR.
The differences are fixed sprung undercarriage with disc brake, and
the deletion of the wing ballast tanks.
Therefore, the remarks In the flight handbook and the maintenance
handbook concerning retractable undercarriage and water tanks do
not apply to the TWIN-ASTIR TRAINER.
The wheel brake of the TWIN-ASTIR TRAINER is a disc brake. The
brake cylinder with the storage tank for brake fluid Is mounted on the
undercarriage box.
The marks for minimum and maximum reserve must be observed.
For refilling use brake fluid DOT 3 (amber).
1. 10.78

FLIGHT HANDBOOK TWIN ASTIR
6
I. 5 Description
The TWIN ASTIR Is a high performance two seater sailplane with a
T-tail, fitted with a retractable undercarriage, upper surface airbrakes
and water ballast tanks in the wings.
This sailplane is manufactured using the latest techniques in industrial
Glass fibre construction.
it is designed for training, high performance and simple aerobatic
flying.
Technical Data:
Span 17.5 m (57.4ft.)
Length 8.1 m (26.6 ft.)
Height 1.6 m (5 .2 ft .)
Aspect
Ratio 17.1
11. Operating Limits
11. 1 Airworthiness Group
(U, Utility, LFSM}
Wing Area 17.8 m•
(191.6ft.2}
Maximum Flying Weight 650 kg
(14351bs)
Maximum Wing Loading 36.5 kg/m1
(7.841bs/ft.2)
The LFSM (Lufttuchtigkeitsforderung fUr Segelflugzeuge und Motor-
segler) published 23. 10.
1975 are the basic rules and requirements for
the licensing of a new type of glider or motorglider in Germany.
11. 2 Permitted operating conditions.
The plane is licensed for:
1· Flight in VMC
2. Simple Aerobatics (Loops, Stall turns, Lazy eight, Chandelle and
SpiA).
3. Cloud flying {When fitted with suitable Instrumentation as defined
in section
11. 3) .
11. 3 Minimum equipment
1. 2 Air speed Indicators reading to 300 km/hr (162 kts, 187 mph)
2. 2 Altimeters.
3. Full Harness Straps in front and back cockpit.
4. Parachute
or back cushion at least 7 cm (3 inch) thick.
5. Loading limit plaque in front and back cockpit.
6. Flight Limits plaque.
7. Flight Handbook.

FLIGHT HANDBOOK TW-IN ASTIR
Cloud Flying.
For cloud flying the additional instruments listed below must be
installed. ·
1. Variometer.
2. Electric turn and slip indicator.
3. Magnetic Compass (Compensated inside
the glider).
11. 4 Maximum -Speeds
Maximum permitted
speed in calm air • ·
Maximum permitted
speed in rough air
Maximum Manoeuvring speed
Maximum winch launch speed
Maximum Aerotow speed
VNE = 250 km/h ( 135kts, 155 mph} I
Vs = 170 km/h ( 92-kts, 105 mph)
VM = 170 km/h ( 92 kts, 1-05 mph)
Vw = 120 km/h ( 65 kts, 74 mph)
VT = 170 km/h ( 92 kts, _105 mph)
Conditions· in rough air are similar to those encountered in rotors,
cJouds, whirlwinds and when overflying mountain ranges.
Manoeuvring speed is the maximum·speed at whi ch full control deflec-
tions may be used. At maximum speed (VNE) the control deflections
should be restricted
to 1/3 of the full range.
Air speed indicator markings
51-105 mph = 44- 92 kts = 82-170 km/h -Green arc
105-155 mph == 92-135 kts = 170 ----- 250km /h -Yellow arc I
at 155 mph = 135 kts = 250 km/h (MSB315-64/3}-- Red line
at 65 m ph = 55 kts = 102 km /h - Yellow triangle
(recommended minimum appr. speed}
Position Errors
The airspeed indicator must be connected to the foUowing sources:
Pitot head in the tail fin. static vents side of the fuselage between the
two seats.
Using a cal - ibrated ASI the posaion error is not greater than ± 2 km/h
or 1 kt or 1.2 mph. A calibration curve is therefore not necessary.
If . 5 Flight envelope.
The sailplane design limit load factors are as follows:
At manoeuvring speed + 5.3 - 2.65
At VNE + 4.0 - 1.5
(Brakes closed and calm air}
14. September2004
7

FLIGHT HANDBOOK TWIN ASTIR
11. 6 Welghtllmlts
Maximum permitted weight without water ballast
Including water ballast .
Maximum permitted weight of non lifting parts •
11. 7 Centre of gravity position
8
650 kg (1435 lbs)
650 kg {1435 lbs)
470 kg (1036 lbs)
The approved range of centre of gravity positions during flight is
260 mm {10.24 inches) to 460 inm (18.11 inches) behind the reference
point, equivalent
to 24.7% to 43.6% of the M.A.C. of the wing.
The reference point is the front edge of the wing at the wing root.
The approved centre of gravity range does not get exceeded by the
payload distribution specified in the loading plan
11. 8.
The exact position of the centre of gravity at flying weight can be
calculated according to
VI· 5.
11. 8 Load scheme TWIN ASTIR
Minimum load in the front seat for all flight .
Maximum load in the front seat
Maximum load in the back seat
Maximum load ln both seats
Maximum load in the baggage compartment .
70 kg (154 lbs)
110 kg (242 lbs)
110 kg {242 lbs)
220 kg (485 lbs)
10 kg ( 22 lbs)
Ballast must be used on the front seat to compensate If the front seat
load is lowerthan 70 kg (154 lbs).
The maximum flying weight
of 650 kg {1435 lbs) must not be exceeded.
Waterballast may only be taken on until the maximum flying weight
is reached.
Water ballast can not be used to compensate
lf the load in the front
seat
Is too low·

F LIG H T HANDBOOK TWI N ASTIR
9
Date of Eq ui pment
Posit i on of Maximum
wetghlng: list used
Empty
cg empty total
carried out for weighing
(Weight } behind refe-
payload
by.
(dale) kg!lb9
rence
kg/lbs
mm/ inches
~. -
---
r-- ·
...
--
-
- --
----
--
1-- "-
- ,- ... ~ ._.....,_
-·
-·-

FLIGHT H A ND BOOK TWIN AS TIR 10
11 . 9 Tow hoo ks
For Aer otow : No se hoo k "E 75''.
For Winch launch: Safety back release hook "G 73".
The E 75 and the G 73 Tost hooks are limited to 36 months after
installation or 2000 launches wh i ch ever occurs first, at which time th ey
are to be
rece rt ified by the manufacture r.
11. 10 Wuk link ttrength recomme~~ ~ ~ ~ · if'f ,) .!.:AI /t~ · )"Z J t.A :;
Winch launch and aerot ow ~0 kg 1323 ±66 lbs
(ie. Tost weak link colour code black-red) rrt-
1
~~ ) - - :1'/
ll . 11 Tire Pressure
Tire size 5.50- 5
11. 12 Crosswinds
2 ,5 -2 .8 atm. 35.6- 3 9,8 PSI
The maximum cr osswind component approved for fake off and lan din g,
Is 20 km/h {11 kt s, 12 mph).

FLIGHT HANDBOOK TWIN ASTIR
U ~ 13 Required placards front and rearcockpit
Maximum flying weight
Without Waterballast
With Waterballast
Airspeed limits.
Never exceed V
Ne
In Rough Air
Vs
On Airotow
Vr
On Winch or Auto Launch
Vw
Airbrakes Open VoF
Manoeuvring
VA
Payload (Pilot and Parachute).
Minimum in Front cockpit
for all flight
.Less·must be compensated with
ballast secured in the seat
Maximum load front
Maximum load back
Simple aerobatics· air speeds
Recommended
entry speed
Loop
Stall turn
Spin
Chandelle
.km/hr
180
180
80
170
650 kp 1435 lbs
650 kp 1435 lbs
km/hr knots
250
135
170 " 92
170 92
120 64
250 135
170
70 kg
110 kg
110 kg
knots
97
97
43
92
92
m
ph ·
155
105
105
74
155
105
154 lb
242 lb
242 lb
mph
111
111
50
105
aerobatics with waterballast is not allowed
14 September2004
11

FLIGHT HANDBOOK TWIN ASTIR
Requiredplacards
Checkbeforelaunch
Full and free movement of controls?
Parachute secured?
Straps tight and locked?
Pedals adjusted and locked?
Brakes closed and locked?
Trim correctly adjusted?
Altimeteradjusted?
Canopy locked?
Cable on correct hook?
Beware: -Crosswind! -Cable breakt
Front Cockpit
Canopy Jettison and Emergency Exit
-Pull red handles on right and left of canopy fully back together
-Push canopy up and away with the left hand
-Release safety harness
-Stand up and get out over left
or right side depending on the
altitude
-When using a manual parachute
grip release and pull firmly to
full extent after 1-3 seconds
By canopy release front and back
Tire Pressure
39,8 PSI 2,8 atm
Maximum weak
link strength
1323 lbs 600 kg
Left undercarriage door.
Baggage maximum
22 lbs 10 kg
Baggage compartment
12

FLJGHT HAND60 0 K TW JN AS TIR
11. 14 Symbols
IOJ)
13
Undercarriage
retract
Canopy open
CanopyJeUson
Waterballaat
Jetlson
.Trim
Airbrakes
Wheelbrake

F Ll G HT HA N D B 0 0 K TW I N AS T t R
Symbols
t
i
QQ
Cable release
Air-vent.
Top left of front
Instrument panel
Pe~al adjustment
Top right of front
Instrument panel
Total energy
compensation tube
14

FLIGHT HANDBOOK TWIN ASTIR
Ill. Emergency procedures
Ill. 1 Exit from a spin
Exit from a spin can be accomplished by
-Full opposite Rudder
-- Neutralise Stick
-Ailerons should be central
- When rotation stops centralise rudder and pull out gently·
Ill. 2 Emergency canopy Jettisoning and exit.
The spacious cockpit allows unhindered exit in an emergency.
lt Is advisable to keep to the following order:
15
a) Pull red handles on left and right back together and push canopy
upwards and away with the left hand.
b) unlock safety belts
c) Stand up and get out over left or right side depending on the
attitude.
d) When using a manual parachute grip release handle and pull
firmly"to full extent after 1 - 3 seconds.
Ill. 3 Landing with retracted undercarriage
lt is possible on hard and soft ground without risk of overturning.
Approach as normal and touch down on two points.
Ill. 4 Others
Flying ·In rain
Wet or lightly iced wings have little noticeable effect on flying. Thick
ice deposits on the wing increase the stalling speed by about
10 km/h = 6 kts.
Stall
Stall out of straight flight or a turn: Neutralise stick and opposite rud-
der to any turn.
Ground Loops
The glider has no tendency to ground loop whilst taking off.
However if a wing touches or the direction changes·by .more than 15
degrees during a take off release immediately.

FLIGHT HANDBOOK TWIN ASTIR
16
Ill. 5 Instruments specifications
Basic equipment: Airspeed
The installation error of an airspeed Indicator
Is not greaterthan 2 km/h
or 1 kt. or 1,2 mph using the pitot tube In the tail fin and the static vents
side of"the cockpit.
The original certification was carried out using a Winter 6FMS4-2 and
a PZL
PR 400 S Airspeed indicator.
A similiar
FAA approved airspeed indicator to meet TSO C 2 reading
to 300 km/h (162 kts, 187 mph) may be used.
Altimeter
The original certification was carried out using a Winter
4FGH 10 and .
a PZL
12 S Altimeter.
A simillar FAA approved altimeter to meet
TSO C 10 with a range to
35.000 feet may be used.
Nur USA-Export

FLIGHT HANDBOOK TWIN ASTIR
IV. Normal operation
VI. 1 Cockpit and controls
Front Seat.
1 Stick 5 Undercarriage lever
2 Rudder pedals 6 Release knob
3 Airbrake lever and wheelbrake 7 Canopy jettison
4 Trim-lever 8 Water ballast jettison
Ventilator top of Instrument panel left side·
Rudder pedal adjustmenttop of instrument panel right side.
17