Schweizer 2-33A Sailplane
Flight - Erection - Maintenance Manual
DISCLAIMER: This scanned version of the Schweizer 2-33A Sailplane manual is provided
warranty of completeness or accuracy. It is solely as a service to builders of scale model aircraft who are in
search of reference material. Under no circumstances should this reproduction be used as a guide for the operation
of a full-scale, human-occupied aircraft. Contact Sikorsky Aircraft Corporation for copies of an official manual.
The SGS 2-33 is a conventional two-place tandem, intermediate-training sailplane, manufactured by Schewizer
Aircraft Corp., Elmira, New York. Its construction is all metal with fabric cover on the fuselage and tail
surfaces. It has a one piece canopy for increased visibility. The wings are tapered in the outboard section, and
have dive-brakes incorporated.
Overall dimensions are: Length - 25' 9"
Span - 51' 0"
Height - 9' 3-1/2"
Wing View -
Aspect Ratio - 11.85-1
Supplement No. 1 to SGS 2-33
2. Dive Brake & Wheel Brake (Ref. Item 2 on Page 1-2)
5. Trim Lever (Reference Item 5 on Page 1-2)
On sailplane serial no. 500 and up,
a ratchet-lock trim installation (P/N 33140G) is provided, superseding the bungee-type trim found on lower
The trim control lever for the ratchet-lock trim system is located just forward and
to the left of the front cockpit control stick. The system is integral with the forward control stick and torque
The trim is operated with the fingers of control stick hand by aft pressure on the locking lever. The control
stick is then moved to the position which gives the desired airspeed, at which point the locking lever is released
to engage the trim lock.
Prior to take-off, the trim should be set (locked) at the elevator-neutral
position which is checked by stick line-up with the trim placard neutral-arrow, located on the floorboard to the
left of the control stick.
After take-off, the desired trim settings may then be obtained as noted above.
Maintenance of the ratchet lock trim system is limited to maintaining security of attachments and periodic
lubrication, with special attention to the spring-cartridge, per codes "A" and "B", Page 2-5 of the Erection and
Maintenance Instructions section of this manual. There are no field adjustments to be made to the trim system or
the spring cartridge.
CHECK ALL POINTS AS LISTED
b. Dive brake hinges and connections
c. Aileron hinges and push rod attachments
a. Hinge points, rudder and elevator
b. Push rod attachment to elevator horn
c. Stabilizer struts and stabilizer attachment to fuselage.
d. Rudder cable connection to rudder horn
e. Tail wheel assembly
a. Release control
Flight controls for free movement including release
d. Canopy attach points and latch
e. Safety belts and shoulder harnesses
f. Rear door and window attach points and latches
Fabric for damage
h. Wheel, tire and brake
i. Static and pitot tubes for water or other foreign
4. Tow Rope:
a. Condition and attachment of rings.
WINCH OR AUTO TOWS
1. Be sure equipment is suitable for purpose
driving car or operating winch should be experienced with equipment and know towing characteristics
3. Never hook rope or wire to empty sailplane.
Winch or auto tows may be executed in the
usual manner using either the forward, or the CG release, although the latter should result in a higher altitude.
There is no tendency to oscillate with either release. Maximum speed for auto, or winch tow. is 69 MPH.
1. Do not climb at full back stick position until a safe height for stall
recovery is reached (75 - 100 ft. ).
2. Level out before releasing. Aero Towing:
1. Trim (bungee lever) forward position recommended for solo take-off.
2. You will notice that aileron
control is somewhat heavy at fast towing speeds, but they reduce to a normal level at
Best gliding speed (L/D) 23-1 at 50 mph . . . 2 place
" " " (L/D) 23-1 at 45 mph . . . 1 place
Min. sinking speed 42 mph 3.1 FPS . . . . . . . 2 place
" " " 38 mph 2.6 FPS . . . . . . . 1 place
Dive - 98 mph
Aero Tow - 98 mph
Dive brakes extended - 98 mph
Auto or winch
tow - 69 mphAerobatics:
Mild aerobatics to 80 mph can be done.
Inverted flight prohibited.Stalls:
Are very gentle and
always straight ahead with no tendency to go off to either direction. Buffeting
occurs before the stall 31 mph solo, 34 mph dual.
WINCH OR AUTO TOWS
The 2-33 will spin, depending on the weight of pilots
and equipment, etc., Care should be taken to
avoid stalls and spins at low
altitude by using adequate air-speed.Useful Loads
weight/s on the instrument panel must be strictly adhered to. This will insure that center
of gravity will be maintained in flight. The weights stamped are maximums and
minimums which are
easily compared with that of the pilot and passenger.
Seat ballast must be added if minimum weight of pilot! s is less than placard
In order to remain aloft or gain altitude it is necessary
to spiral. The diameter of a thermal is normally
quite small, therefore, a fairly steep bank is required.
Although this is general practice, it may not be
necessary in areas where large
diameter thermals are found. The best flying speed in any thermal, at
of bank, is a few miles per' hour above the buffet-before-the-stall.
Stalling speed-level flight 31 mph 33 mph
" " -30° bank 33.5 mph 35.5 mph
34-37 mph 35-38 mph
Spiralling speed 38 mph 42 mph
Keep in mind that the steeper the spiral, the higher the minimum-sink and stalling speed will be. Sometimes it is
necessary to spiral very steeply and sacrifice slow speed and low sink to remain within the limits of
This is especially true in strong, small-diameter thermals.
The SGS 2-33 can be slipped both forward, and while turning. The slipping-turn is done in a
normal procedure, but due to limited rudder area, the forward slip must be done with very little low wing and full
rudder. The airspeed should be kept between 45 - 50 mph for fastest rate of descent.
It is general practice to fly a traffic pattern. Downwind and base
legs and final approach. Extra speed is also used depending on wind velocity and gust conditions. It is good
practice to add 1 mph to airspeed for each mph of wind. Spoilers
Approach should be made high, with use of dive brakes. Dive brakes increase sink, which in turn makes a steeper
and more controllable glide path. They can also be used to lose altitude rapidly at any time during a flight, or
during a tow to take up slack, or to lower sailplane from a too-high position. When flying solo, the stalling
speed of the 2-33 is 31 mph with dive-brakes closed and 34 mph with dive-brakes open. For dual flight, the speeds
are 33 mph and 35 mph, respectively.
It is unsafe, however, to make an approach with dive brakes open in the speed range of 36 to 43 mph as the
rate of descent is so great that a proper flare-out for landing cannot be made. Touch
Can be done with dive brakes either open or closed although it is preferable to land with them
open. With dive brakes open, the glide path is quite steep, therefore, a flare-out must be executed 2 - 5 ft.
above the ground at 43 - 46 mph. By holding a level attitude close to the ground, the sailplane will settle to a
smooth, level touch-down. DO NOT FLARE OUT TOO HIGH
- this will cause a very hard
landing and may result in injury to occupants or sailplane. Touch down with dive
Is executed by letting the sailplane land itself at, or near, 40 mph. Be careful not to ease stick back after
touch-down. This will cause a steeper angle of attack and the sailplane will lift off.
Taxiing after touch down
Even though sailplane is on the ground, it should
literally be flown to a stop with use of all controls. Wheel brake may be used if a quick stop is desired or
Getting out of the 2-33
On the ground it is tail down
when empty, and nose down with pilot in the seat. When pilot gets out he should keep his weight on the side of the
cockpit until he is in a position to lower the tail gently to the ground.
GENERAL FLIGHT PROCEDURE IN STRONG WINDS
1. Be careful during ground handling operations.
Keep tail high to and from tie down area.
2. Keep well up-wind of your landing area.
3. When going against wind, it is good practice to add wind
velocity to air speed at best L/D.
Speed at best L/D (solo) 45 mph
+ 15 mph
speed 60 mph
This speed will give a better glide angle than a slower approach.
4. Land into the wind whenever possible. In crosswind landing, crab into the wind to maintain desired path over
ground and at the last moment, straighten ship to line of flight and touch down. Be careful while the
ship is rolling.
Downwind landing in high winds - Land with brake full on and maintain control as long as possible.
The 2-33 should never be left unattended in strong winds or gusty conditions. Tie down points are at each wing
where main struts are attached and at tail wheel bracket. Be sure ropes and stakes used for tying down are
adequate and in good condition.
Flight Limitations for 2-33 and 2-33A
In any aircraft, it is important to know the opera ling limits and that exceeding these limits can highly
endanger the aircraft and its occupants. The following information is provided for the 2-33 and 2-33A at 1,040
lbs. gross weight.
The speeds with which you should be familiar are:
Placard Speed (never exceed) with or without
Dive Brakes open 98 mph
Placard Speed (never exceed) for aero tow) 98 mph
Speed to begin maneuvering with caution 65 mph
Placard Speed (Never
exceed) for auto or winch tow 69 mph
In the 2-33, at speeds over 65 mph, the pilot
must maneuver with caution. The maximum load factor which should be attained in flight is 4.67 G, and the pilot
can easily exceed this in abrupt maneuvers at speeds over 65 mph. The speeds between 65 mph and the 98 mph placard
should be treated as a cautionary range and maneuvering within this range should be gradually reduced to a minimum
as velocity increases.
The 2-33 limit load factor of 4.67 should not be exceeded in operation. A safety
factor of 1.5 is required by the FAA which gives an ultimate load factor of 7.0, but this safety factor is
required to allow for material variations and inadvertent atmospheric conditions. Because of its light wing
loading, a sailplane can develop very high loads if speed limitations are not rigidly adhered to. Normal category
light airplanes are usually certified to a limit load factor of 3.8 G's.
Understanding the Flight Envelope
The FAA required design flight envelope is presented on the following page. On the horizontal axis are
indicated velocities in miles per hour, and on the vertical axis are load factors expressed in "G" units.
3. When going against wind, it is good practice to add wind velocity to air speed at best L/D. 4. Land into the
wind whenever possible. In crosswind landing, crab into the wind to maintain desired path over the ground and at
the last moment, straighten ship to line of flight and touch down. Be careful while the ship is rolling. The
straight lines labeled "gust load factors" represent the effect of the FAA required 24 ft. per second gust on the
sailplane as speed varies. They diverge from the one "G" situation where the glider would be at rest or in
perfectly balanced level flight. The curved lines diverging from zero "G" represent forces which can be induced by
moving the elevator (or other) control abruptly at various speeds. As you can see, the faster you fly the more
effect moving your controls will have. Gusts will also have more effect as speed increases. The speed for
maneuvering with caution occurs where "G" loading from an abruptly moved control meets the 4.67 limit load factor.
Assuming smooth and limited movement of the controls, the placard or "red-line" speed occurs where gusts could
meet the 4.67 limit load factor without any maneuvering.
Understanding the Flight Envelope cont'd.:
Normal placard speeds are reduced 10% from design speeds
to provide an extra margin of safety. Thus, on the graph, the diagonal hatched area indicates speeds at which you
must use caution in maneuvers. You should neither maneuver nor fly so fast as to expose your ship to loads within
the cross-hatched area marked, "NO".
It can be inferred from the graph that abrupt maneuvering in gusty
conditions is dangerous and can lead to very high "G" loads.
In normal operation the major cases of high
"G" loads are tight spirals in thermals which would not normally exceed 2 or 2.5 G's. Winch or auto towing can
produce high loads, but if the auto-winch placard speed is observed, this will be within safe limits. The best
ground launch climb is obtained at speeds well below placard limits.
Although the 2-33 is capable of
performing some aerobatic maneuvers, they must be done with extreme caution since it is very easy to greatly
exceed the placard or cautionary speeds in improperly executed maneuvers. Inverted flight is not permitted.
Aerobatics should not be done without previous instruction in two-place aircraft.
2-33A GROSS WEIGHT
To Be Determined:
1. Whether the actual CG of the particular 2-33 to
be flown will fall within the above limits.
2. Whether total gross weight is not greater than the maximum
allowable 1, 040 lbs. for any 2-33.
WEIGHT AND BALANCE CALCULATIONS
SGS 2-33 or 2-33A
SCHWEIZER AIRCRAFT CORPORATION
ELMIRA, NEW YORK 14902
WEIGHT & BALANCE, MODEL NO. SGS 2-33A SER. NO. __ 369 __
DATE February 27, 1975
ELMIRA, NEW YORK
ERECTION AND MAINTENANCE INSTRUCTIONS
MODEL SGS 2-33
ELMIRA, NEW YORK
SGS 2-33 - ERECTION PROCEDURE
A. TO REMOVE A/C FROM TRAILER
1. Remove trailer from towing vehicle and
2. Raise rear of trailer and block in position with sawhorse, jack or other suitable means.
3. Remove wing-to-trailer tie-down from wing tip skid brace from L. H. wing. (Note: R. H. wing is mounted
on the L. H. side of trailer and L. H. wing on R. H. side of trailer.)
4. Remove upper wing-to-trailer
attach pin, support the wing to prevent twisting.
5. Remove lower wing to trailer attach pin and remove
wing from trailer and place on ground.
6. Remove blocking means from rear of trailer.
7. Raise and
block the front end so that aft end of the trailer rests on the ground.
8. Remove the rear tail wheel
bracket-to-trailer jack attachment, bolt and support fuselage.
9. Remove front fuselage tie downs and
carefully roll the ship aft out of wheel well and off trailer into assembly position.
ASSEMBLY OF THE AIRCRAFT
1. With the fuselage in an upright position, attach wing struts to fuselage with (2) AN7 (7/16") bolts and
#2 Commercial safety pins.
NOTE: The wing and strut attach bolts must have a grip-length of
1-13/16" min., to avoid threads in bearing.
2. Lift and place L. H. wing in position and attach to
fuselage with an AN7 (7/16") bolt in front fitting and an AN6 (3/8") bolt in rear fitting. Install #2 Commercial
safety pins in bolts.
|All trademarks, copyrights, patents, and other rights of ownership to images and text used
on the Airplanes and Rockets website are hereby acknowledged. If you own material used here and want it to be removed,
please send an
e-mail stating so.
Copyright 1996 - 2014
Kirt Blattenberger, BSEE
My lovely enabler, Melanie