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Laying up an aircraft


pmccarthy

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Looks like the pride and joy might be in the hangar for several months. What can we do to protect it?

 

I know about special dehydator plugs, but we probably don't have them and will not be able to get them. So what can we do with what we can get?

 

-engine dehydration?

-special oils?

-fuel in tanks, line pumps and carb?

 

Any ideas?

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Drain tanks, lines and float bowls. Drain engine oil and fill with inhibitor oil. The Rotax manual should have the necessary process, assuming that’s your engine.

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Looks like the pride and joy might be in the hangar for several months. What can we do to protect it?...

A timely thread, PM. My only suggestion is to not leave MoGas too long in your barbs. A mate did and ended up with some sort of varnish coating the bowl.

 

I had planned to prepare my plane for long storage this weekend. That involves coating the steel bores of my Jab engine with oil. The best way to do that is warm up the engine thoroughly, then tie it down and run it hard while injecting 2T oil downstream of the carb.

 

The safest way to thoroughly warm up my engine without overheating the heads is to do a couple of fast runs up and down the runway. I'm almost certain to be the only person for miles, but Is that legal?

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You would be best to drain the oil replace it and then get it nicely hot. Fly for 45 minutes and put it away in the hangar and remove one plug from each cylinder and squirt a storage oil into each Cyl with some fitting that will distribute it evenly, with the appropriate piston at BDC, then place a special dehydrating plug into each cylinder, which will change colour when it's absorbed as much water as it can. . Squirt a dewatering fluid into the muffler and pull the engine through backwards 2 plus turns. to get the mist into the ports. I'd turn the engine over about once a month and just put some WD in the cylinders once a month. I don't believe in running the motor at all. Turn it over now and again in the normal direction and add more oil to each cylinder at least each year. Plug the exhaust exit. as well. The CASA site used to have a full advice on inhibiting engines. if the engine is out you can arrange to tilt it in many positions to distribute the oil all through the internals. Some stands permit this. Nev.

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Whip the plugs out and spray some engine oil into the cylinders. Replace the plugs.

Put Glad wrap over the carburetor intake where the air filter box connects. Make sure you place a flag there to remind yourself to remove the Glad wrap.

Put airtight seals in the exhaust pipe outlets.

Put Glad wrap around the opening of the pitot tube.

Sticky tape over the static air port.

Put stands under the undercarriage legs to get the tyres off the ground.

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It sounds silly at first, but it might be an idea to spray around the door frames, and any other openings into the fuselage, with a crawling insect spray. You don't want to turning crosswind on your next flight and find there's a Redback on the pilot's seat.

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If the order comes out - no more flying - run the engine once a month and even go for a taxi. Use your imagination and pretend you are flying.

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  • 2 months later...
...I had planned to prepare my plane for long storage this weekend. That involves coating the steel bores of my Jab engine with oil. The best way to do that is warm up the engine thoroughly, then tie it down and run it hard while injecting 2T oil downstream of the carb...

 

Today I discovered the downside of that. Went for a fly and the engine was not producing the sort of power I'm used to. Worse, it was burning 16lph instead of 11. When I opened it up the best I could get was 2700rpm.

On the ground there were a few misses so I tied it to a post and gave it a good workout. At WOT it ran like a hairy goat, so I checked the plugs, etc. When I removed the main jet assembly a big blob of dirty oil came out!

 

On a taildragger, the Jab carb is the lowest point of the engine, so some my corrosion-inhibiting oil has made its was downhill into the bottom of the carb intake duct. Amazed it started and ran well enough to get me aloft.

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That puts a big question mark over injecting oil. The same happens with premix 2 stroke if the carb(s)) are not drained. The fuel evaporates and leaves (thick) oil and your engine can run lean and melt a hole in the piston..There are risks leaving stuff idle but running it and not getting it fully warm is itself a bad idea. You need close to an hours flying to get an engine to full equilibrium heat . Put new oil in is part of almost any preparation ever suggested.. There ARE inhibiting oils (or were).The dehydrating plugs probably fitted the 18 mm older plugs but surely smaller ones are available. They change colour when they are exhausted of their dehydration ability but may be able to be heated in an oven to rejuvenate them. The bores on steel and cast iron cylinders should be protected as well as exhaust ports for valve guide and stem corrosion. Dry Nitrogen was always used to get rid of moisture in Magneto's in the tropics. I'd spray the bores with a good product every few months and pull the engine through a couple of turns with the Maggy carefully stopped from making sparks for safety. Birds nest in engine cowls etc. I'd clean any mud from surfaces and wash with something containing a bit of canauba wax and take the weight of the tyres if you can.. Some people wrap cars and other VALUABLE items in a plastic sealed bag and fill it with Nitrogen.. Everything deteriorates when just left exposed to the elements especially if you are near the sea. If you have a wood plane, some protection against mould would be a good idea. Nev

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All good advice, Nev. The humidity in our inland area is normally very low, so corrosion and mould aren't issues; I take precautions anyway, and the recent wet weather is extra reason to be vigilant.

Good point about warm-ups; I give mine plenty of time and when CHTs get to around 120C if there's no traffic I do a couple fast runs up and down the strip till the oil gets to at least 70C.

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I asked my car mechanic about this the other day (he also used to work on Rotaxes!)

 

His advice was to use a product called Inox, available from Repco. Similar to RP7 / WD40 but clings better. Also recommended the dehydrating plugs, or failing that, oil soaked rag stuffed in the plug hole. (Aircraft Spruce have the plugs for about USD$10 each - AN4062-1 DEHYDRATOR PLUGS 18MM | Aircraft Spruce)

 

I've got a couple of cans of Inox on order, will check the Australian availability of the dehydrating plugs.

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How do you get the inox over the valves? The regular tube it comes out of is wrong for this. You need a 180 degree bend, and better would be a reversing mister which directed the spray oil backwards in a cone.

I can imagine such a nozzle but does anybody know if they really exist, or do you have to make your own? I can imagine a tight-fitting blanked off tube which fits over the inox plastic tube and has a few 45 degree backard facing holes drilled in it.

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How do you get the inox over the valves? The regular tube it comes out of is wrong for this. You need a 180 degree bend, and better would be a reversing mister which directed the spray oil backwards in a cone.

I can imagine such a nozzle but does anybody know if they really exist, or do you have to make your own? I can imagine a tight-fitting blanked off tube which fits over the inox plastic tube and has a few 45 degree backard facing holes drilled in it.

 

I've been told that the aerosol moves it around enough after you spray it in that it coats pretty much everything. I'm doing mine once a month - was using RP7 but picked up the Inox today.

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How do you get the inox over the valves? The regular tube it comes out of is wrong for this. You need a 180 degree bend, and better would be a reversing mister which directed the spray oil backwards in a cone.

I can imagine such a nozzle but does anybody know if they really exist, or do you have to make your own? I can imagine a tight-fitting blanked off tube which fits over the inox plastic tube and has a few 45 degree backard facing holes drilled in it.

Used to be able to get a nozzle as you describe - I had one for spraying rust inhibitor/liquid wax into box sections & the like. Made out of bronze, shaped a bit like a 22 with a hollow core & three rear facing one forward, jets. Fitted onto a stiffish tube that allowed me to poke it up into all the many voids in a car body/chassis - turn on the juice, wriggle it around up/down and it would coat the cavity in a few moments. Did a great job. You could probably get someone to turn one up for you.

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Whip the plugs out and spray some engine oil into the cylinders. Replace the plugs.

Put Glad wrap over the carburetor intake where the air filter box connects. Make sure you place a flag there to remind yourself to remove the Glad wrap.

Put airtight seals in the exhaust pipe outlets.

Put Glad wrap around the opening of the pitot tube.

Sticky tape over the static air port.

Put stands under the undercarriage legs to get the tyres off the ground.

 

Hi Old Man Emue,

 

I like your advise, as far as it goes. My situation is a little diffrenet to most participating in this conversation - my Rotax 912 is no longer in the aircraft.

 

The engine is solidly mounted on a small pallet and the covered with a dust proof purpose built box.

 

I have plugged all openings to engine oil, fuel and cooling system. Caped off carburettors and using tightly rolled microfiber towel pieces, plugged all four exhaust ports.

 

So far I have put 2.5 L of clean/unused AeroShell Sport Plus 4 into the block and then tilted the engine to near vertical left/right/forward to bath all components in oil. I plan to regularly move the oil around in this way.

 

I will not e able to hand "crank" the engine as this will result in the oil being ejected.

 

I plan to do as you suggest and squirt a quantity of oil into each cylinder OR as Marty_D sugests INOX liquid (not aerosol) - which would be best ?

 

Is this sufficient ??

 

What more can I do to preserve my engine during its absence (expected to be many many months) from its aircraft?

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