Engine/Electric Pre Heat SOP

Heres the question...

I keep my 9A in my hangar that is heated to 60 degrees. When I have my Reiff pre heat plugged in without an engine cover I get 92 degrees, with the cover it is 114 degrees.

So what is everyone getting for temps when their aircraft is plugged in and is it advisable to keep it plugged in even when I know I am not going to be flying for several days?

Will the 114 degrees keep the oil warm enough to keep the moisture at bay?

Thanks

Not for extended use...

The folks at Mattituck told me that in an operating engine the sensor location will typically reflect ~180F when the temperature in the sump is at ~212F. Of course, that is the minimum temperature moisture must reach to boil off. If you're not getting that, your essentially turning the inside of the engine into a greenhouse - and that's only going to accelerate corrosion.

N42AH said:

Heres the question...

I keep my 9A in my hangar that is heated to 60 degrees. When I have my Reiff pre heat plugged in without an engine cover I get 92 degrees, with the cover it is 114 degrees.

So what is everyone getting for temps when their aircraft is plugged in and is it advisable to keep it plugged in even when I know I am not going to be flying for several days?

Will the 114 degrees keep the oil warm enough to keep the moisture at bay?

Thanks

Click to expand...

The subject of whether it is advisable to leave it plugged in or not is subject to debate. There are good points on both sides.

That said, why preheat if the hangar is maintained at 60F? Personally, I wouldn't bother unless the airplane was kept in <40F temps..

N42AH said:

Heres the question...

I keep my 9A in my hangar that is heated to 60 degrees. When I have my Reiff pre heat plugged in without an engine cover I get 92 degrees, with the cover it is 114 degrees.

So what is everyone getting for temps when their aircraft is plugged in and is it advisable to keep it plugged in even when I know I am not going to be flying for several days?

Will the 114 degrees keep the oil warm enough to keep the moisture at bay?

Thanks

Click to expand...

No preheating needed in your case. Your airplane thinks it's April all winter.

Build and use an engine dryer system.

In your case, I would not even worry about the engine heater. It may actually promote engine corrosion but consider that unverified.

Exactly

The moisture that is inside your crankcase is not coming from outside sources (at least if it is its a very small amount). Where its coming from is the fact that you have burnt fuel on your previous flight.

Think about this. When you burn fuel the exhaust gas is mainly CO2 an H2O. Some of that gets pushed past the rings and into your crankcase. Now when you land you have this nice hot crankcase, the air inside of which is almost saturated..I.e it is holding as much water it can at that temperature.

Now the crankcase temp falls to the hot air dewpoint (say 150F) and a LOT of moisture will condense on the inside of your case..And drip all over the cam.

So the moisture is in there no matter what you do..Except the warmer you keep the engine the more corrosive that moisture will be....Not a good combination.

This Theorum (which is an educated guess on my part) is why I don't buy the "fly to drive out the moisture argument" cus all your doing is putting it right back in there. Flying often simply re-coats the cam with oil to prevent rusting. If there is moisture in the oil then its sitting at the bottom of the case where in theory it won't do any extra harm.

As has been previously mentioned the best solution is to build a dessicant dryer and remove the moisture..If it works inside your gun cabinet it will work in your engine.

Frank

ok....so someone has to ask, might as well be me...How does build a dessicant dryer?

miyu1975 said:

ok....so someone has to ask, might as well be me...How does build a dessicant dryer?

Click to expand...

http://home.pcisys.net/~ronlee/EngineDryer.pdf

Next time you fly, after getting out of the plane go open the oil filler cap and observe anything that may be coming out. I can almost guarantee that what you see is not fairy dust. Once you see that, the notion that you evaporate water from the oil becomes a laughable concept. UPDATE: I had an "ah ha" moment when I realized that the oil that comes out of the breather tube get there as a vapor. Thus what I see coming out of the oil filler tube after a flight may be oil vapor. I need to find a way to collect, condense and examine that vapor. Even if it turns out to be oil vapor, I will still use the engine dryer system.

I open mine after every flight, use the engine dryer system and have started using Camguard to help protect it.

Harbor Freight has some nice blue dessicant that turns pink with use.

Walmart has the stone filters, tubing and aquarium pump. I started with the 10-30 gallon size then went with a 30-60 gallon. Yesterday I realized how I can return the smaller one to service in parallel with the larger unit for more dry air. (Tim Allen grunt).

Search the forums

I detailed my build on here..pretty easy.

Note Petco have their own brand of pumps which have much more capacity and were much cheaper than the named brand.

As Ron pointed out HF has the cheapest dessicant (I uses two packets in my open loop system) and it maybe recharged by drying out in the oven.

Two long columns were more effective (I use 1.5inch drain pipes two of them each 5 foot long in seies) than a short fat coke bottle.

Also as Ron mentioned..The first time you see the column of steam rising out the oil filler (with motivation from the fish tank pump) after the flight you to will be a believer!

Frank

isn't part of a having a pre-heater also intended to be better for cold starts too though?

miyu1975 said:

isn't part of a having a pre-heater also intended to be better for cold starts too though?

Click to expand...

Sure, but my experience shows that until temps get <40F, starting performance doesn't diminish very much. So, unless your airplane is stored in those conditions, pre-heat probably isn't necessary.

Great Comments

Gentlemen, thanks for the great comments and suggestions.

Frank, you are correct. The Petco deals are far cheaper. I would go that route if starting one now.

http://tinyurl.com/3axmqzo

Update: Read the reviews.

The Harbor Freight desiccant is Central Pneumatic Item 97924. 2.2 lb bag. I believe another guy used almost two bags to fill a 2L soda container.

It is 97% Amorphous silica, 2.8% Aluminosilicate and 0.2% cobalt dichloride. The last component may not be the correct name but is what gives it the color and color change when hydrated.

I use a cork with tubing coming from the desiccant container and that plugs into the crankcase vent tube at the lower cowl aft opening. This is contrary to using the oil filler tube as the dried air inlet point.

I verified that the Harbor Freight desiccant does change color from blue (dry) to pink (hydrated). Then I went online and ordered two packs (4.4 pounds) of it to use. I believe that this will work better than the other two desiccants I had before. Now I need to find the T fitting and second pump to increase the airflow. Once I do that I will take a picture of my setup in case it helps others.

Here is a picture that shows the basics. The dark object on the left is the aquarium pump. The two air outlets have hoses going to a T fitting. The outlet of the T fitting goes to the Coke bottle which contains the desiccant. The hose from the pump just goes far enough inside the coke bottle and ends suspended outside the desiccant although that may not matter. The other hose you see coming out of the cork in the Coke bottle extends towards the bottom of the bottle. The end is attached to a stone filter and is covered by desiccant. That same hose ends on the other end by going through a cork that allows it to be inserted into the bottom of the breather hose at the lower cowl opening. Pretty simple.