I am familiar with cowl covers in winter but I see photos where some folks have the propeller blades and spinner covered with custom insulated covers; why the prop too?

The prop conducts heat from the crankshaft so the prop is insulated to minimize heat loss from the engine.

Not as much as an issue with composite props, but aluminum is highly thermally conductive. The prop exposed to cold winds, will act like a huge heat sink cooling fin and suck the heat out of the engine via the crank. Plus if applicable, will keep the oil in the prop warm.

Hoeschen wrote:I am familiar with cowl covers in winter but I see photos where some folks have the propeller blades and spinner covered with custom insulated covers; why the prop too?

With Snow, Ice, Rain, you don't have to clean off the prop, Also will keep most of the ice from building up inside your spinner and create balance problems.

If you're in cold country, take a look at a plane that's been outside in the weather overnight in frosty conditions....conditions where there is frost on wings/fuselage, etc.

Assuming an engine heater has been plugged in, take a look at the propeller. While everything else is covered in frost, that aluminum propeller will be totally free of frost. Why? Because that aluminum is bolted directly to the crankshaft....the very core of that engine, and that propeller has been acting as a very effective radiator, conducting heat away from the core of the engine.

Put a prop cover on an unheated engine, and as M6RV6 noted, it'll keep the prop clean. Keep an insulated cover on your prop while pre-heating, and it'll raise the temperature of your engine's core a few degrees, and/or speed the heating process.

Park outside for a few hours in cold? Put an engine cover on, AND the prop blade covers and the engine will cool significantly slower.

MTV

Plus it gives the wind something to blow away. There's a derelict C310 sitting on the ramp at KAWO, with a very nice set of prop covers complete with the tail number embroidered on. Correction, make that a half a set of prop covers.

The last couple of times I've put my airplane away in the non-insulated hangar, although I've plugged it in, I've been too much in a hurry (read "too lazy") to put on the cowl cover and the prop/spinner covers. Boy is that proof that these things do something good! The engine has been warm enough to start easily, but so much of the heat has escaped that touching the engine, it's not "warm", just not cold. The prop and spinner are cold. Yet when I take the extra 4 or 5 minutes to put all that stuff on, the engine is warm enough that the oil temp gauge is off the peg, and the prop and spinner are quite warm to the touch.

Cary

And here I thought it was because you bump into the prop all the time in winter, when your glasses are fogged and you can't see sh*t

denalipilot wrote:And here I thought it was because you bump into the prop all the time in winter, when your glasses are fogged and you can't see sh*t

Well, that's a good reason, too.

Cary

Because Coyote...

BRD wrote:Because Coyote...

43rd use for a dead coyote....

I've also heard speculation that if you leave the preheaters plugged in all the time, an uninsulated metal prop can cause condensation to form on the crank, since the heat sink effect of the prop will make it cooler than the inside of the case. I don't know if that's ever been proven though.