The International Cessna^® 170 Association

I was ready to order a Reiff engine heater but decided to go the cheap route this winter. I think George convinced me that forced air may be better.

I found a 1500 watt space heater that has a squirrel cage fan. It was $40 but it moves the air better than the little milk house heaters. I am not convinced that 1500 watts is enough heat and I don’t want to prove it by not being able to start a cold engine.

Setting the heater upside down on a stool directs the airflow right into the cowling. No ducting needed. This is where a picture is worth a 1000 words.

Two questions

I don’t want to heat the gascolator and the fuel in it. Assuming no sparks from the heater and no fuel leaks, how stable is 100LL in the gascolator if it does get warm?

With a blanket on the cowl, 10 F, plane inside, how long will it take to heat the entire engine? How do I know it’s ready to go?

Bill

I'm in a T hangar, not heated though. I put a little cube electric heater on top of my battery box inside the cowl door ('56 C172 with a cowling door on the pilot's side) and I have a Kennon engine cover. works great, an hour or two and ready to go. not so easy away from home but still doable.

somebody (seems I have seen it advertised by Tanis) has a phone activated timer that remotely turns on your power, that would be great if you don't have a set time to go flying every day. I can't remember where I saw it though, sorry.

Bill... remember that little trick I've talked about using a BBQ thermometer about 14" long down the oil dipstick tube (to check accuracy of the Oil Temp gauge)? It certainly would be a nice thing if your oil temp was at/above 50 degrees F.
Otherwise....how about putting your hand thru the front openings and feeling the engine case with your hand? Fell warm? Good.

I'll have to check the brand but I've got a heat pad on the front bottom of the oil tank on my 140's O-200 and there's something on each cylinder. Forget exactly what it looks like. I have a Kenon cowl cover. If I plug it in for four hours the entire engine is very warm to the touch, the oil on the dip stick is warm and flows. I've found it helps a lot to cover the prop too. It seems to suck a lot of heat out of the engine. I have an old quilt I wrap the prop up in. The prop is warm when I unbundle everything. Works pretty good. I do that in my unheated hangar. I haven't yet parked out somewhere else in the winter. I'll have to figure that out this winter.

I picked up an electronic outlet timer at Lowes and when I know I want to go flying early in the morning I plug it all in the night before and set the timer to come on so that when I expect to get to the hangar it'll be warm.

HA, I saw that article. It was in GA News several months ago. Hope this helps.

flat country pilot wrote:I was ready to order a Reiff engine heater but decided to go the cheap route this winter. I think George convinced me that forced air may be better.

I don't think forced air is necessarily better. The Reiff system, which uses a heating pad on the oil pan and bands around the cylinder bases, does a very good job of warming the entire engine safely (no danger of starting a fire), and very conveniently (you just plug it in, wherever power is available).

The problem comes from that convenience, I think -- it's easy to just leave it plugged in, or otherwise have the engine warmed up and then not go fly. This can lead to internal rust and corrosion if the airplane isn't flown enough. There's a flying club here with Lycoming-powered Cessna 172s and 182s, which leaves all the aircraft plugged in in a cold hangar all winter long. They've done this for at least 20 years that I'm aware of, with no maintenance issues arising from it. But all their aircraft are used several times per week.

I think the Reiff and Tanis systems are fine if you fly the airplane after preheating it. My mechanic believes bands around the cylinder bases heat the engine more evenly than plugs in the cylinder heads. A good engine cover like Kenon's is important as well.

I'm in a heated hangar now, so I'm no longer using my Reiff system at home. Nothing better than that!

Here's a link to a good article on preheating: http://www.reiffpreheat.com/Article-Busch.htm

Best Regards,

John

I'd only suggest this for everyone's consideration:
The cooling fins on the cylinders are for the purpose of...??? (Answer: Transferring heat...originally conceived as transferring heat from the cylinder to the atmosphere, but in actual practice, to/from the cylinder to/from the heat source.)
A cylinder which is hot...will dissipate heat from itself to atmosphere thru it's fins. A cylinder which is cold will absorb heat from atmosphere thru it's cylinder fins. Conclusion: Fins facilitate the transfer of heat by design.
Little bands that heat the cylinder will lose that heat to atmosphere thru the cylinder fins. (It matters not if the cylinders are heated by combustion or by someone's little heating-bands... but in the case of either example, the heat is thrown away by the fins.)
However, in the reverse situation, a warm atmosphere surrounding an engine will absorb that heat thru the cylinder fins, and that heat will be passed onto the rest of the engine.
George's conclusion: Hot air surrounding an engine (thru natural condition or thru a hot-air provider such as a forced-air heater) will be absorbed by that engine, and that absorption will be facilitated by cylinder fins which were originally intended for the reverse process. Therefore George believes it's both theoretically and practically better to heat the entire environment of the engine (such as with a forced air heater) rather than heat only a small portion of the engine (such as the cylinder bases and/or the sump like the Reiff/Tanis systems do.)
Heck of a lot cheaper too, and no approval basis required.

George,

Up north we use a blanket or an insulated cowling cover, maybe even prop and spinner covers, so the fins don't radiate into cold space. The whole engine is warmed with the cylinder bands. The ambient air inside the cowling is close to the engine's temperature. In a freezing cold hangar here in Minnesota, it's easy to see 90 degrees inside the cowling with Reiff heaters, measured as oil temp and CHT. You can use a thermostat to limit that to what ever you want. Here's an example: http://www.doityourself.com/invt/0307942.

(I apologize to all you Alaskans and Canadians for referring to Minnesota as "up north." It's all relative, isn't it? )

Best Regards,

John

In either case, the engine are should be covered with a blanket/etc., and the prop should be viewed as a large heat-sink which sucks heat away from the engine to atmosphere. Closed-foam wrap (such as used by prop shops to protect the blades during shipping) is cheap, can be rolled up and stored in a small space, and will effectively slow down the heat loss thru the prop.
I opine that such measures are even more effective with more-effective methods of heating an engine.

Trivia question: If an object that normally generates heat and normal desires are, that while it's operating, it should not be restrained from dissipating it's heat by any coverings/wrappings/etc.,.. if that object is covered by a band shaped like a hose-clamp... wouldn't that small area be effectively insulated from dissipating it's heat as efficiently as it might otherwise? (OK, well I guess that in winter conditions that might not be so critical with all that cold air blowing into the cowl... but wouldn't that little device still be thwarting desired cooling during the rest of the year?)
Yeah, I know,...it's just a little thing.
And the glued-on/clamped-on devices are very convenient, if expense is not an issue.

George, I think the Reiff cylinder bands shouldn't pose a cooling problem, due to their location at the base of the cylinder BELOW the cooling fins

just as the crankcase doesn't have any fins either, there are parts of the engine where you don't necessarily need fins to get rid of the heat - the bases of the cylinders effectively get cooled from splash oil

but I know that the cylinder base can get pretty hot too - I once years ago had a poor experience with TCM reduced-clearance pistons that bubbled the paint on the cylinder bases on the break-in. That was my indication that their tolerances were too darned tight (they changed them after lots of us had those problems). but that was mechanical mayhem, not normal operations.

Yeah, I realize it's like lookin' for fleas on an elephant. The reason no cooling fins exist down there is to provide room for cyl-base attach hardware, not because no cooling is desired in that location.
But the engine case is primarily not a cooling issue and mainly is used as a gear-case, oil-tank, and assembly-mount. It is a large area that does not produce heat itself, (is actually a heat-sink), and is cooled sufficiently by air and pure mass. This engine does not have an especially high therm-output, doesn't even require an oil cooler in most applications, and that's why no cooling fins are there (along with economies of production.)

I'm just a guy down-south who rarely has to deal with cold wx on a daily basis and can get by on a cheap, low-tech, solution to a rare problem. If I lived up "nawth" and had to deal with this problem on a daily basis, I would probably take the easy way out and install an engine heat system of some sort and use multi-grade oil. Phoooey!

(How's that for equivocating...err... I mean flexible, open-minded thinking?)

I have a Reiff system on the 172 (lycoming) and it is great.

Next time I'm out at the hangar I will take a picture of what I am using for the 170... total cost about 25$. Basically one of the 1500W milk house heaters with some ductwork from the hardware store mounted on the front to allow a metal dryer duct to extend up into the cowl. Once the cowl is covered with a blanket it will heat the interior (and the entire engine) to 90-110F on a cold winter day. My buddy has been using this on his C-140 and RV-6 for years with good success. He actually leaves it on 24/7.

Thomas

Here is a link to a picture of my preheating set up. $40 heater, $10 stool and $20 blanket. I'll try it for this winter before I jump and put on the Reiff.

http://www.popularaviation.com/PhotoGallery/4522.JPG

Bill

Has anyone tried a heating pad on the oil sump? I am speaking of a small self adhesive, 250 watt heating pad that is sealed on all 4 sides with silicone. The following links will provide some details. Seems the claim of temperature rise is excellent for winter operations here in the "real" north country of Manitoba!

http://www.canadiantire.ca/browse/produ ... 4761680331

http://www.canadianpolarpad.com/installation.html

the oil pan pad is better than nothing but not much. you really need some kind of cylinder heat to go with it or forced hot air preheating. by itself it just isn't enough.