FES Discus 2c - Limitations and Restrictions; Airspeed and Powerplant Limits

FES Flight Manual, v1.18 May 2020
Page 8 of 35
2. Limitations
2.1 Introduction
This chapter includes operation limitations, instrument markings, and placards
required for the safe operation of the sailplane equipped with a Front Electric Sustainer
system.
2.2 Airspeed
Airspeed limitations for the use of the FES system and their operational significance
are shown below:
Speed
IAS;
km/h /(kts)
Remarks
V
PO
Maximum speed with
a rotating propeller
160 / (86)
Do not exceed this speed with a rotating
propeller (at any power setting)
V
POmin
Minimum speed to
start the motor
80 / (43)
Do not start the motor below this speed
V
POmax
Maximum speed to
start the motor
160 / (86)
Do not start the motor above this speed
Warning: select your motor start/stop speed correctly:
- flaps must be in a positive setting; (depending on glider type)
- make sure your chosen speed for motor start/stop is at least 8…10 km/h
(4…5 kts) higher than the stall speed for your flight configuration.
2.3 Airspeed indicator markings
FES equipped sailplanes do not have additional indicator markings compared to
pure gliders. Blue line marking on the airspeed indicator can be added, representing a
range of speed with the best rate-of-climb. This range depends on the glider type. Usually,
it is between 80-90km/h, with a positive flap setting.
Marking
(IAS) value or range
Significance
Blue line
80-90km/h
Best rate-of-climb speed