Nitro engines create an awful amount of oily mess in and around your nitro RC helicopter. You can’t prevent it, but you can minimize its effects.
As was discussed in the nitro fuel section, nitro model fuel is around 20% oil – a 1:5 oil to fuel ratio.
Most gasoline 2-stroke engines use oil ratios in the 1:20 -1:40 range. Almost all the oil is burnt off in the exhaust.
This is not the case with nitro engines. Most of the oil makes it through the exhaust and it gets everywhere. It leaves the engine in a fine atomized fog. This fog will get into every nook and cranny of your nitro RC helicopter and will condense into a nice slimy layer of oily goo.
This oil is generally not a problem but it can hurt your radio gear - specifically the receiver, servos, and gyro/FBL Unit. You should protect these components as much as possible.
Wrap your receiver, battery pack, and gyro in small plastic bags to keep the oil film off them. You should only consider getting water proof servos.
These should be called oil proof servos because not many people fly their RC helicopters under the water – at least not intentionally. Most quality servos these days for helicopters are water proof and have gaskets to prevent water or oil from getting inside.
If you don’t have water proof servos you can open them up and apply a very small quantity of automotive silicon gasket maker to the two mating halves of the servo case and a little dab of silicon where the servo wires enter the servo.
Just make sure you don’t get any silicone on the circuit board or the gears. Don’t worry, silicone won’t glue the servo together and you will be able to pull it apart again if you have to.
Oil goo on all the moving mechanical parts of your nitro RC helicopter of course won’t do any harm and in some cases will actually do a little good to keep things moving freely.
The one thing to watch out for here is if you land in or hover over any sand – there will be little bits of sand stuck to any oily surface on your heli. The best way to get it out of sensitive areas is with a little compressed air.
You should also check the area around your engine carburetor to make sure there are no sand grains near the air intake. To clean the engine and engine area if this happens I like to use methyl hydrate.
I plug the carburetor hole and spray a liberal amount of methyl hydrate that I put into an ordinary squirt bottle all over the engine and engine area. I then blow it dry with compressed air and things are squeaky clean again.
Methyl hydrate is safe for everything on your helicopter and evaporates quickly. Do not use acetone or automotive carb or brake cleaners. These chemicals will melt certain plastics and destroy the finish of your helicopter.
After a day of flying, carefully wipe down your nitro RC helicopter with some paper towels to remove the oil residue off the pod or fuselage cover and the main and tail rotor blades. Keeping your rotors clean of oil and bug guts is very important.
I started using those blue shop paper towels and they work much better than standard paper towels. They don’t fall apart and soak up a lot more oil. For a real good cleaning every month or so, I will usually saturate a blue shop towel with methyl hydrate and give the heli a good wipe down.
A clean heli is a happy heli!