The data on this page is gathered from the factory published owners manual and are deemed to be correct.
However, it is the pilot’s sole responsibility to verify and fly the a/c within the limits of factory-published information.

Weight and Balance
Empty Weight 886 lbs.
Maximum Weight 1279 lbs.
Maximum Useful Load 393 lbs.
Minimum front seat load for all flights* 154* lbs.
Maximum Front Seat Load 242 lbs.
Maximum Rear Seat Load 242 lbs.
Maximum Baggage Compartment Load 22 lbs.

Trim Weights must be installed if front seat load is less than 154 lbs.

Front Seat Pilot Weight 121-137 lbs 138-153 lbs
Number of Trim Weights 2 1
Air Speeds
Maximum Speed calm air Vne 135 Kts
Maximum Speed to Deploy Spoilers V 135 Kts
Maneuvering Speed Va 92 Kts
Maximum Aerotow Speed Vt 92 Kts
Minimum recommended approach speed Vref 51 Kts
Maximum crosswind component V 11 Kts
Stall Speeds Without Dive Brakes With Divebrakes
Solo 36 Kts 40 Kts
Dual 40 Kts 46 Kts

Flying in rain raises stall speeds by 6 Kts. With wet wings increase take-off and approach speeds accordingly.
True airspeed is greater than indicated at altitude. Vne decreases according to the following table.

Vne
Altitude 0-10,000′ 13,000′ 16,000′ 19,000′
Vne 135 Kts 121 Kts 115 Kts 109 Kts
Performance
Speeds to Fly Solo Dual
Minimum Sink 43 Kts 46 Kts
Best L/D ~36/1 51 Kts 57 Kts

Glider N4446Y Documents

G-103 Checklist
N4446Y Loading Graph
2011 N4446Y Weight and Balance

Glider Manuals

N4446Y USA Twin II Flight Manual
N4446Y USA Twin II Maintenance Manual
N4446Y USA Twin II Repair Instructions
2014 TDSC G39EU

Equipment Manuals

Transponder ATC4401-1 Installation and Operation
FSG60M User manual
FSG70M Squelch Adjustment
LX Navigation LX16 Variometer Pilots Manual
Winter 6FMS423 Airspeed Indicator Information
Winter STV-5 Variometer Installation Manual