I was interested in hearing some different viewpoints on preheating. Right now we bring our plane to a heated hangar 3-4 hours before a flight. While this is a good option it costs $30 each time I do this. Is there a more economical way? The aircraft (C-172) is stored in a un-heated hangar right now. We run multi-grade (15-50) oil in it. I am manily looking for some ideas on pre-heating the aircraft without having to pay the $30 everytime I want to go flying.

I just used a 1500 watt electric heater and mounted a piece of dryer vent tube to it. Works good. I think if you check www.treetopflyers.com their is a thread just recently posted about early winter in MN. and one of the posters MN_GB, posted a picture of one almost exactly like what I have.

Keith

I use a propane Reddi-heater and a 6' duct with a 90 on the end. About 15-20 minutes and it's ready.

How often do you fly?

The reason I ask is most everyone in this neck of the woods uses either Reif or Tanis heaters. As long as one doesn't let it go too long between flights just leave it plugged in with a cowl cover on it. If you are going to leave it for a time, then unplug it.
I'm sure somebody will fuss about doing that but I've never had any issues and lots of folks do it this way. If you don't feel comfortable doing that, just plug it in 3-4 hours before you plan to fly or have somebody do it for you if you don't want to drive out just for that.

Brad

Anything less than 40 deg F, we preheat with the 12 volt devise from this company. http://www.flameengineering.com/Engine_Preheaters.htm

We have no electricity in the hanger so we have the 12 volt unit. If we had electricity we would use an oil pan heater.

Tim

Thanks for the replys everyone.

WWHunter I will search thier forums.

BRD I normally try to fly twice a month, but I sometimes I can get in 3 times a month. I looked at the Tannis solution, but I want something a little more economical (i.e. CHEAP)....I know I know I'm a cheap guy!!

Greenhorn,

Go to Reiff Preheater's web site at

http://www.reiffpreheat.com/product.htm

There's a good discussion of how and when to preheat.

They have a variety of pre heat solutions, at varying prices. If you don't want the whole enchilada (and their system is a good bit cheaper than Tanis') you can install just the oil pan heat pads.

Buy a good insulated engine cover, plug the sucker in overnight before a flight, and you should be good.

If temps are getting really cold, the full system would be best, but not necessary if you're looking at warmer temps.

You could also drape a sleeping bag over the cowling and see if that works well enough to hold the heat in.

In any case, give it overnight with the sump heater only, it'll take a while, but it's relatively cheap, and simple. Stays with the plane all the time.

MTV

I don't know what the other heaters run money wise, but I saw a heater I hadn't seen before in the last Sporty's that I got. It's called the AeroTherm, it's electrical, and runs $400. (page 51 if you're looking for it).

Last winter our club put together a propane heater made out of a dolly, a propane tank from your grill, and an electrical fan to blow the air. I know it sounds a little redneck, but it is actually a really nice set up, easy to use, and a lot cheaper than calling the FBO for a preheat. Somebody that knew what they were doing put it together.

Good luck.

I also have the Red Dragon...only used it once so far but it did a great job with my insulated cowl cover. At 20 d F it only took about 15 minutes - I figure at 20 or 30 below it would take about 30-40 minutes. That's about how long it takes me to take the wing covers off, shovel some snow out of the way, load and preflight the airplane anyway.

The 12V model clips to either your car battery or the airplane battery to run the electric fan, and then the rest is propane powered (they make a 110 volt model also.) Nice thing is after the engine is warmed you can jam the hose through your window and pre-heat the cabin, or more importantly your gyros behind the panel. You need to buy the six or 12 foot hose extension for this.



I bought a small 5 lb propane tank from Home Depot (the standard "grill size" is 20 lb.) to take on trips up here. I usually stay around 2000-3000 agl so I'm not worried too much about pressure changes in the cabin. They also make an adapter to use the small disposable camping propane bottles.

Edit: This is the same one from Flame Engineering in the post above. But I found that Aircraft Spruce sells the exact same model made by the same people at a price quite a bit cheaper than the manufacturer (when I bought mine it was about $150 less!) Check out Spruce's website for the latest price.

Once and futur,

DO NOT stick that Red Dragon hose into the cockpit to pre heat the cockpit, unless you want all sorts of problems down the road. Propane contains LOTS of moisture. Stick that hose into the cabin, and you're blowing lots of water into the cabin area.

You may have seen folks doing this with a Herman Nelson heater, the difference is that a Herman runs the induction air around the burner can, then blows it out through the hose. In other words, its dry heat, not moisture laden propane exhaust.

Secondly, 15 minutes of heat with a Dragon at 20 degrees is probably okay, IF you let the engine soak for a while after heating. That's the trick with any of these heat sources, is letting the heat normalize throughout the engine.

heat the hey out of it for a few minutes, and it'll start, cause the combustion chambers are warm, and the fuel will atomize, but your oil is still in a big cold lump down there, wrapped around the (very expensive) crankshaft.

So, if you give it a quick heat, put the engine cover back on for fifteen or twenty minutes, and let things normalize a bit. Your engine will thank you.

MTV

MTV I was actually thinking "what if you stuck the hose of the heater in the cockpit to warm it!!!!" Thanks for the heads up.

Superdave what did your reddi-heater cost you? How long does it take to heat the engine? Also, does it blow air over a burner box or does it contain propane exhaust? So far this sounds like the way to go if you are looking for an inexpensive solution....

Greenhorn,

If you don't have power accessible here is another link on treetopflyers that shows how a couple of guys have solved the problem. These are made from a small single burner camp stove.

Good luck,
Keith

http://www.treetopflyers.org/cgi-bin/ya ... 1134996123

I use an oil pan heater on my Skywagon. If you have access to a power plug it is a great option, just plug it in the night before you are going flying. As far as pre-heating the cabin, buy a cheap high wattage hair dryer! I found one that hangs over my rear bench seat. I just plug it in through the baggage door and let it run for 20 minutes while I am doing my pre-flight and loading baggage. It's amazing how fast a hair dryer warms up a small space like an aircraft cabin.

Somewhere in my deep dark memory, I seem to remember someone using a Whisperlite stove along w/ some metal clothes dryer ducting as an in the field heater. Ducting runs under the engine and the stove was remote from the AC.

The Whisperlite International will run on a number of different fuels and gets hotter than all get out. Available through REI and the hose is Home Depot.

TD

Greenhorn-
The Reddi-Heat was $89 at Lowes. I think it's 30000 btu. I put a 6' galvanized duct with a 90 on the end so the exhaust blows up the bottom of the cowl. It is 110vac so I plug it into an inverter hooked up to an Oddesey battery that is solar charged. Or I made a generator out out a lawn mower engine and a 100 amp car alternator. Takes about 20 minutes when it is cold.
MTV is right about not heating up the cabin with it because the exhaust is really nasty and full of water. Also, the CO detector goes nuts. I have a preoiler which I believe is secret to a good preheat. I heat up the oil in the pan and then flip on the preoiler which circulates the warm oil thru the motor.
I start the engine after the oil temp reaches 50df. I'll take a picture of the contraption next time I'm out at BDSSIR.
Dave

There's a commercially available preheater that uses a small camp stove called the Northern Companion. It is an elegantly designed and well built piece of equipment.

You can make something similar, but don't forget a couple of key factors:

1) you need to make sure that stove doesn't tip over

2) you also have to realize that those stoves put out sparks. Sparks rise. So, the Northern Companion has a flexible SCAT hose and a fine mesh to catch the sparks, and prevent them from going straight up into your engine compartment. Remember where the gascolator is?

3) You must watch all these combustion heaters ALL the time. Sure, you can pull your wing covers off, and do other preflight chores, but you'd better be paying close attention, cause if it lights off, it won't take long to be unsalvagable.

4) Don't blow yourself up lighting the stove.

5) Remember, if you use a propane implement--propane liquifies somewhere around -30. It may or may not work if its really cold.

4) I like long slow heat, and I like electricity. For all the reasons above.

But, suit yourself-there are lots of options. Just be smart about it.

MTV

TomD,
If you click on the link I provided I believe this is the same type you are talking about.

Mike (MTV) is 100% right as far as the propane and extreme cold are concerned. It spits and sputers a lot when cold....if you can keep it burning!! If you build a recirculator (let some of the heat keep the bottle warm)around the propane bottle helps a lot. I also prefer electric for the same reasons MTV stated.
But I have a hell of a time finding a current bush to plug into when away from the house! LOL

Keith

mtv wrote:Once and futur,

DO NOT stick that Red Dragon hose into the cockpit to pre heat the cockpit, unless you want all sorts of problems down the road. Propane contains LOTS of moisture. Stick that hose into the cabin, and you're blowing lots of water into the cabin area.

Y

MTV

Whoops! Thanks for the advice. -30 and moisture in the cabin = bad.

But I have a hell of a time finding a current bush to plug into when away from the house! LOL

That IS the problem isn't it? At my home strip I have electricity for a small ceramic heater cube in my cowl (and my cabin) until I get around to buying a Tanis/Reiff but it's when I'm in Talkeetna or at some unimproved strips that I need the Red Dragon. Talkeetna not so cold. Others...

There is some guys around here that just duct the exhaust from their car into the bottom of the cowl. In my opinion not too smart for obvious reasons. But I guess it would work in a pinch. When i was doing electrical work we sometimes would use the truck exhaust to heat pvc conduit so we could bent it, but that was only if there was no electricity to run the heater.

Jon

Great subject as I have been learning this year.
For around the house, I keep a 200w bulb under the cowl in conjunction with an Alaska Wing Covers cowl blanket. The engine tonight is 77 degrees at 10 degrees ambiant. We also use a 1500w electric heater for in the cabin 1-1 1/2 hours before flight.
While out at the cabin, we have been using a Coleman one burner stove with a 6" x 4" adapter to 4" duct into the cowl. There have to be some accomodations for wind, (8" deep aluminum pan with holes drilled for air flow) and I believe in a long soak of heat. Many different metals with different rates of heat absorbtion. It takes about 2 hours at 15 degrees and 3-4 hours at -5 degrees. The engine will start at much shorter times but that is not the goal.
I have a number of friends with the Red Dragon and two with stories of fires. I also have a few friends with the Northern Companion and no fires but out $500.00 These are (N. C.) seem really good but given a little patience and fore thought, the money might be used towards something else.
That's this years observations in the North, next year may hold something wildly different.