a couple of weeks ago I got reminded why you’re not supposed to rely on the engine in a powered glider.  I was flying cross country, but wasn’t feeling well. After 150km I got low and needed the engine. Close to the chosen airfield I fired up the engine on base and climbed away. Since it was the middle of the afternoon, I soon found another strong thermal and climbed back to cloud base. The flight back home was no problem and I started my final glide from way below glide path, hoping to gain some 2000ft on the way (we had streeting). 60km later I was on glide path for McCready 0 and I decided to press on, leaving behind a 5kts thermal (2.5m/s). Sure enough I hit lots of sink thereafter and found myself 1000ft below glide path soon after. With enough fuel on board I wasn’t worried and I was ready to put it to use should the need arise. The terrain on the last 8 miles to the glider port is almost unlandable, so you always want to carry enough energy into the final glide. Since it appeared that wasn’t going to happen that day I decided to motor home from the last private landing strip. I lifted the engine, turned on the ignition and hit the starter: nothing. Check-list, engine full out, ignition on, throttle closed, choke, starter. Again silence. Now only 600ft AGL my heart started pumping. Gear down, airfield is to the left, stay in glide range. Voltage check: 11.2V. Wow, this should read at least 12.6V, 11.2 is awfully low. But there’s enough power to run the ignition and fuel pump, just not the starter. I decide to dive and try to windmill the propeller to a start and use this maneuver to make my base leg. When I push the nose over to gain airspeed my altitude drops to 250ft AGL – not very comfortable. Phubb, phubb, phubbbububbbb, and the engine fires! I pull up, control my airspeed carefully to not stall and at the same time to not overspeed the engine under full power. When everything is stable I turn left on final and fly along the runway under power to climb away. Another voltage check reveals that the alternator is not working. I now run fully on battery power. I decide to motor the last 8 miles to my home field, as I cannot be sure to have enough battery power left to retract the engine after shut down. In that case my glide ratio deteriorates to 16:1. After a couple of tense minutes I reach the field uneventfully and am still able to stow away the motor. Upon closer inspection I later find out that one of the copper cables from the alternator had disconnected from corrosion and therefore the alternator didn’t produce any current. That was easy to fix and now everything is back to normal. Nevertheless this incident served as a reminder to never completely rely on that metal thermal in the back. One day it might just not be there for you to bail you out…