I recently asked (on a mainly GA Power pilots’) forum what extra
hazards a glider pilot might need to think about, when acquiring a
self-sustaining glider. (I am getting a FES, but not the self-launch
variety.)

Many of the responses related to internal combustion engines, rather
than electric. For what it is worth, this was my question and my first
thought, followed by is the list I got from various people, edited to
avoid duplications;

-------------
Normally, flying a pure glider, there are certain hazards that power
pilots all too frequently fall victim to, that we don't. One example
is pressing on into increasingly bad weather, lowering cloud base,
often resulting in CFIT when the plan B of turning back turns out not
to work. In a glider, it is almost impossible to be in this position
in the first place, because you can't maintain height under a lowering
cloud base that is turning to rain or worse. In fact you wouldn't be
going cross-country initially in those conditions.

By next season, I hope to have a sustainer engine in my glider. This
will enable me to cruise for about one hour at 50 knots at level
height (e.g., to get home instead of landing out in a farmer’s field).
Although it is unlikely that I would be going cross-country in the
conditions described above, it is conceivable that I might use
thermals to reach a patch of bad weather, and so need to avoid the
temptation to fall into the same trap and end up with CFIT.

My question is: what other pitfalls, not normally faced by a glider
pilot, might I now have to be aware of, when going into sustained
powered flight for up to an hour? (I cannot take off with the
sustainer motor – still need a conventional glider launch by winch or
aerotow.)

---------------------
Engine fires - not something a glider pilot normally has to worry
about.

Effect of icing.

Carb ice.

Engine failures - you'd have to go through some of the same drills as
a powered pilot.

The effect on your compass. It will need swinging twice - once with
the engine on and working and once in the pure glider mode.

The effect of propwash on the handling. if it blows over the elevator
and or rudder it will make them much more powerful and also torque and
gyroscopic effect will alter the handling.

Depending on where the thrust line is it will also affect the pitch,
particularly if it is pylon mounted.

Added weight of engine and fuel will complicate C of G /Ballast/etc
calculations.

Fuel contamination will be a 'new' problem.

Mag problems, freezing of moisture on ignition.

Fuel pump problems - assuming your engine is above the tank..

Noise and vibration will increase fatigue.

Vibration will affect fatigue life of glider sealing of hatches etc
assuming your engine is a 'pop out'.

'Jamming' of controls from cockpit to engine potential 'heating' of
cockpit when engine is running.

Extra drag if engine sticks in 'out' position.

----------------------

What do others think?

Chris N.