Keeping the hot air in the eng. compartment

[mhorowit]

Fired up my homemade pre-heater and began pumping hot air into the eng. compartment from underneath. Shoveling snow from around the ship, taking my time. After 1/2 hour I felt the top of the cowling and it was barely warm. Turns out all the heat was leaking out the grill in front !.
I threw a blanket over cowling and clothespinned it together so air wouldn't escape thru the grill and she gradually warmed up.
Anyone have another, possibly less cumbersome way of keeping the heat where it belongs? - Mike

PS - delightfully warm as long as the sun was shining in, but when I turned around to come home you could really feel the difference; got 1.5 on the engine, which was my objective

[Lubeck]

Mike, you need an insulated engine cover. Look at the pictures that Dick Smith posted and you will see what is needed. One word of caution about preheating. It will take longer than one hour to sufficiently heat the engine to the inner core. It may seem warm to the touch but it is cold on the inside. Northern Pilot did some testing and it required about three hours. I usually install my catalytic heater the night before and it is nice and toasty by the morning.

[Dick Smith]

Saving heat

Mike, you might go down to the thrift shop and buy a few old quilts and blankets(warm ones). You can rig up a passable cowl cover using several together. Buy a cheapy space blanket(the little one-time use survival type). Lay the foil space blanket over top of the engine cowling and let it drape down, especially over the grills and prop opening. Have enough blankets/quilts available to completely wrap the engine cowling, so as to prevent warm air from rising and escaping anywhere. Wrap a blanket around the prop blades and the spinner. You will eliminate a lot of "radiator effect". In the included picture, you can see how "wrapped up" my plane is. There is a fan/heater inside. Also, I pull the bottom rear of my cowl cover up, by wrapping a rope or bungee cord around the boot cowling, to close off the opening under the engine boot cowling, where the hot air comes out in flight. When it's really cold, during the heating process, I use foam rubber strips to seal off this lower opening. Be sure and remove "all" such material before starting the engine. I don't add heat to the engine compartment when the nose tank is clear full, to avoid expansion and overflow of fuel. Also, if you have a leaky wingtank valve, that fuel can move down and top off the main tank. Something to think about. Dick (P.S. Thomas answered you while I was typing this response...he has it right. It takes a while.)

[taylorcraftbc65]

Engine heat

Dick Smith,
I live in El Paso, and it dosn;t get anywhere NEAR as cold here as it does where you are. ( No I'm NOT rubbing it in).
My question is this, at what expected temperature should I
pre-heat the engine at sundown the day before. Down here,
pilots just stick a light in the engine compartment. Thanks in
advance for your replies, from a former resident of Ithaca, New
York. Sabrina

[mhorowit]

Thanks;
how do you keep your footing in the snow/ice when propping her?
Why did you wrap the prop? You said 'radiator effect' - are you trying to minimize loss of heat via the crankshaft out to the prop?
That sounds extreme, but that's how I read your comment! - Mike
PS - just how cold does it get at night? here we'll have several nights in a row at 10*

[Dick Smith]

Re: How cold and prop covers...

I'll attach what I think is a pretty good article on the starting of aircraft engines in cold wx. I pretty much agree with what is written here. http://www.avweb.com/news/maint/182846-1.html#howcold If it's below freezing, I want to put heat on mine. I've seen an 0-200 started at minus 10 F. without heat...glad it wasn't mine. My C-85 would start at 11 Deg ...might start at 10 Deg F...wouldn't start at 9 Deg. F. If I could hear the Bendix snap...it would start... if the priming was done properly and the primer charged, ready to help get past any stumbling. I've since decided to heat it properly if I can. It's got a fan and heater with a thermostat under the cowling right now. I figure it's a lot cheaper to burn some electricity than overhaul it.
Regarding the prop covers, several years ago, Northern Pilot magazine covered some tests done on various makes of engine covers, with their various types of construction, materials, etc. They used some very sensitive instruments to measure heat loss. The prop blades showed up as definite sources of continuous heat loss. Since they are directly tied to the flange & thus the crank,, they contribute to whatever bearing clearances exist under the given temperature. When it's really cold, the engine is just plain tight and I believe it's a function of clearance as much or maybe more than thick, stiff, oil. Dick

[Dick Smith]

Safe footing on snow/ice & how cold.

Mike, I much prefer to prop from behind. Open the right door all the way, until it's against the boot cowling...turn my hat around...hold on to the door frame with the left hand...put my right foot firmly on the front, left surface of the right ski, so that the sole of my boot rests on the screws that protrude through the ski, holding the UHMW plastic bottoms on. During pull/through...cold or hot...I keep in mind what that prop will do to me. When the engine starts, my route takes me (carefully) backward...gently closing the door, never letting go of the front strut until I can follow it out and duck under the struts. You don't have brakes when you're on skis, so you want to know what you're throttle setting is going to make happen! You wouldn't believe how slick wet ice can be! Don't hesitate to tie the tail or even start the engine with the fuel off...you have plenty of time to go around behind, reach in and turn the fuel on before it quits. For what it's worth. The coldest I've seen here is minus 47 Deg. F...the coldest wx I flown the plane in was minus 21 Deg. F. The coldest I've ever "felt", was at minus 37 Deg. F in the back seat of a 90 hp Champ..."that was cold"! And dumb! A lot of your options after a forced landing at that temperature are in the toilet...cold wx can kill you. Dick

[taylorcraftbc65]

Engine heartig

Dick,
Thanks a lot for your responce to my question. The article you enclosed was very informative. I contacted Tanis on their site
and asked them to send me information on what they make
for my A-65. You have been a great help, thank you again.
By the way, is there a 337, or STC to where I can put those
COOL looking doors on my BC-65? Anybody know the answer to that one? Sabrina