Heating It Up

While the recent drop in temperatures may be a welcome change for some, the cooler weather does present some unique challenges to flying. The most evident of these challenges is the difficulty in starting a cold aircraft engine. Besides hard starting, it is said that one cold start can cause up to 300 hours of wear on an air-cooled aircraft engine. To combat the cold, all of Sweet Aviation’s aircraft have been equipped with engine pre-heaters. These are electrical heating elements placed on the oil sump and on each cylinder to heat the engine. The effects of plugging in the heater are not instant, however, and it should be plugged in for several hours before attempting a start. (The aircraft are normally plugged in all night when overnight temperatures dip below around 40 F.) To assist the next person, we also ask that you help out the Sweet Aviation staff by plugging in your airplane after your flight, as well as installing the cowl plugs to help hold the heat inside the cowling.

If you arrive on a brisk morning to find that your airplane was not plugged in overnight, don’t despair. There is faster pre-heating option. Sweet Aviation also owns a salamander-type propane heater. While it is more work, it is able to heat the engine much faster than simply plugging it in. To operate the salamander-type heater, the heater hose should be inserted slightly into one cowling inlet, while a cowl plug obstructs the other inlet to force the hot air down, instead of simply letting it exit the other side. When using this with aircraft with composite cowlings, care must be taken not to leave it in one side for too long as the heat will cause the composite to sag. The heat should be alternated side to side for several times until you can reach in and feel that the engine case is warm to the touch.

The largest grief-causing error I see during the winter the removal of the cowl plugs and unplugging of the engine pre-heater during the beginning stages of the preflight. This causes the engine to be completely cold again by the time they settle into the cockpit and ready to start. The cowl plugs should remain installed and the heater plugged in until the last possible minute before starting.

The engine is not the only thing the cold is hard on. Battery performance also suffers in the cold, and I recommend conserving electricity during the preflight and pre-start operations. This means leave the strobes off as long as possible, and don’t run the flaps up and down more than necessary.

Cooler temperatures are great for aircraft (and instructor!) performance, and winter is my favorite time of year to fly. Proper preflight procedures combined with engine preheating will help to ensure efficient and enjoyable flying all winter long.