The Cellar Image of the Day

Gliders are assisted taking off by a tow plane or winch with a long cable, then riding air currants and thermals like a raptor,
quietly soar for hours. If they can’t make it back to their base they land where they can and fold the wings while waiting for
the guy towing the trailer to fetch them home.

Motor Gliders can take off then shut down the engine. After soaring they can fire up the engine to get home.
This Stemme S12 motor glider can retract the prop and close the nose cone for aerodynamics after the engine cools.
It has a waiting list of about 9 months and costs $349k to $369k (275k to 291k GBP, 307k to 324k euros).

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Unlike the earlier Stemmes, the S12 is equipped with a single 31.7-gallon fuel tank hidden in the fuselage behind the cockpit. At 55 percent power, the Rotax will burn about 3.4 gallons per hour. By mixing powered aircraft time with soaring, the S12’s range can be enormous despite being officially listed as only 950 nautical miles. At 10,000 feet, the S12 will speed along at upward of 140 knots true.

The aircraft’s 12-volt battery can be charged by a set of solar panels embedded in the outer fuselage behind the canopy to extend the use of avionics during flight. Also nestled near the solar cells is the opening to a rear baggage compartment capable of holding 44 pounds of goodies, turning the S12 into a true cross-country soaring machine. In case a couple of hefty pilots happen to choose the S12, the aircraft is equipped with a water ballast system to make moving the center of gravity rearward a snap. The S12 also includes provisions for two optional oxygen bottles for high-altitude flight.

I stumbled upon this topic yesterday when I clicked a sidebar link to this. I was confused until I figured out the engine, with 5-blade prop, retracts into the body of the glider behind the rear seat.

They said an experienced pilot can get the motor stowed or working in like 5 seconds. That should be fast enough to get out of trouble.

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Schempp refers to the propeller as being "noise optimized" and you can see that the blades are free to flap (forward) like helicopter blades (which flap up) so that the asymmetric thrust axis from having the propeller disc offset from the rotational axis doesn't place bending loads on the hub.

I remember reading about one that had a ducted fan in the fuselage behind the pilot. Vents opened to allow the thrust out the sides. The vents closed to clean the drag up when not running the fan.