You won’t own a Rotax 912-series engine for long in cold climates to know it’ll take a long while for the oil temperature to reach 120° F—the prescribed temperature before coming up with the power for the before-takeoff run-up. That wastes time and fuel. Moreover, in subfreezing temps the electronic ignition might not even fire the spark plugs unless the starter cranks the engine at a 220-rpm or more crankshaft speed. And so because we keep our 912 ULS-powered Van’s RV-12 in an unheated New England T-hangar (where typical indoor winter temps can easily drop to 30° F or less), we installed a Reiff pre-heating system (along with a winterization plate kit) for the 912 engine. It’s an easy but critical installation.
Warm the Oil Tank, Crankcase
Installation is refreshingly straightforward. First, off with the RV-12’s upper and lower cowling—again—to gain access to the oil tank on the right side of the engine, just forward of the battery box, and for access to the crankcase. The standard Reiff system includes a silicone 50-watt HotBand that clamps around the base of the oil tank, and a 100-watt HotStrip bonds to the bottom of the case with the supplied Aremco epoxy-in-a-bag.
J-B Weld epoxy #8265 is an approved epoxy, and it’s all about surface preparation and the proper mixing/curing of the epoxy. Reiff warns that any surface paint must be stripped, and both the surface of the case and the heating pad scuffed with a Scotch-Brite pad, followed by cleaning with acetone or alcohol.
Once the epoxy is well kneaded and the bag opened, work fast. Wear surgical gloves and goop it on sparingly—the ideal thickness on the HotBand surface is three sheets of paper, or 0.010 inches. There’s plenty of epoxy supplied to also bond the small thermostatic sensor to the underside of the oil tank. The Aremco epoxy fully cures in roughly 48 hours at 75° F, and the JB Weld epoxy in 24 hours. It’s too late for those temps in mid-November, so once the elements were in place, we put a blanket over the engine and stuck a heat lamp on the floor below it, measuring an 80° ambient temperature after sitting overnight. That cured the epoxy enough to connect the thermostat and both heating elements to the supplied wiring harness.
Reiff has good guidance when it says to form a healthy bead around and over the heater edges to sort of lock it in place, and to seal the openings in the corners and the lead wire exit hole to keep out oil and water so the heater doesn’t short. I think it also works well for wire strain relief. Still, the harnesses and connectors (white Molex) are high quality and there’s plenty of it to neatly connect the components together and for making service loops. We routed the AC plug over the top of the oil tank so it’s accessible when opening the upper cowling oil-check door. There’s also a ground wire that gets attached to the engine.
Plenty of Heat
The thermostat on the oil tanks limits heating the oil to around 190° F, and while the 150-watt kit comes with a single HotPad and HotBand, Reiff sells additional HotPads as an option. At an ambient temperature of 23° F—and plugging the air inlets with cowl plugs or tennis balls, stuffing a towel in the oil cooler inlet, and covering the cowling with a blanket—the standard system heats the 912’s oil temperature to 96° F in 12 hours. Reiff says to plug in the heater at least three to five hours before starting the engine, but 10 to 12 hours offers maximum heating.
As always, the best plan is to simply fly often. Reiff adds the caveat that continuous heating during long periods of aircraft inactivity is not recommended, and it “does not advocate continuous preheater use as a means to prevent corrosion in inactive engines.” We plan to fly our plane regularly, unless the weather tanks for long periods as it can in New England.
The standard 150-watt Reiff system is $305, $475 for the 250-watt system, and $630 for the 350-watt system. The system also fits the Rotax 914-series engines. We’ll check back after a winter of use and report back on the system’s reliability.
Nice system. For my Rotax 915iS powered gyro plane, I attached a car battery blanket to the oil tank and ran its cord and separate connector for a battery charger to the lower right side of the firewall. I might have to look into a heater plate for the crank case, though the Rotax engines are dry sump.
My Cessna 180 came with Tanis oil heater attached to the oil pan. To that, I added a hot air blower which I made by taking an electric space heater, riveting to the output grille a clothes dryer wall flange and a length of 4-inch dryer hose which is stuffed into the cowl flap. I cover the cowl with a quilted moving blanket and plug the air inlets with inlet plugs.
All of the heaters plus a 24-volt battery charger as well as the gyro heaters are connected to separate WiFi controlled smart outlets which I can turn on with my phone. I can also set them up to turn on at a programmed time and turn them off when I arrive at the airport. The C-180 is heating up right now as it’s 32 deg F at the airport and we’re going to take a ride up to the mountains.
Good timing.
I was just thinking about installing an engine heater on my RV-12.
Thanks!