Metal Gear lubrication for DS

[darryltarr]

Hi Guys,

Having spent several years with some very high tech metal to metal gearing I would like to share some information with you. Below are a couple of photos of my EC135, in particular the metal gears used on the JetCat SPM5-HM. You can see the metal gears at the top rear of the Cabin.

Being open gears (meaning not immersed in a casing or sump), perhaps the worst product to use for lubrication is oil. The reasons may be obvious but for those who don't know I will elaborate:

1. The viscosity of oil is generally very low (meaning very thin), and this viscosity will decrease when the gears heat up during operation. The result is that the oil becomes thinner and will generally fly off the gears.

2. Many oils will not be able to absorb the heat generated by the gears and may break down leaving carbon deposits, which in-turn become gritty. Not Good.

3. Castor Oils (being vegetable based), tend to leave a higher deposit of carbon and will break down at lower temperatures. Synthetic oils in general will perform a lot better.

Over the past several years I have been using GREASE to lubricate my open metal gears. I started with a PTFE based grease, which handled the high compression very well but unfortunately it too tended to fly off the gears with the heat build up.

The best results to date is from Tri-Flow RED Grease. This is an extreme pressure (high compression) grease that can handle high temperatures. It also has very good viscosity (thicker than Teflon), it is waterproof and provides good anti-corrosive protection. Below is a photo where I have used it on my Diabolo S Main Gear.

Remember I do live in the Middle East where the Summer temperatures are Hot and although geographically we are at Sea Level our atmospheric pressure is also low. This results in the density of the air being thin and can be similar to those who live at 3,000 feet above Sea Level. In short we loose performance both aerodynamically and mechanically, and the operating temperatures of our our equipment can be extreme.

This information may Not suit your climate and flying environment.

Cheers,

Darryl

[Mercuriell]

Good info Darryl, thank you :

I started with Dry Fluids Gear Lube on the SD metal gears and it seems to work OK. The gears were a little noisy so I dried Gerds supplied green goblin blood and they were certainly quieter, as you say though the oil does get flung off necessitating a few drops every flight. I have used the Tri flow red grease for years on my TDR gears and it is excellent - only thing I don't like is the resultant grinding paste when grit gets in, in enclosed gear boxes I think it the best. I have gone back to oil for the gears and using DiamondLube, so far so good !

[darryltarr]

Very good point John with regards to the grit.

My EC135 gears are fairly well protected (being inside and at the rear of the cabin), and I do find I have to give them a full clean, then re-grease every 10 flights. As the Main Gear in the DS is slightly more exposed I may have to do a full service every weekend.

Thanks for the info.

[Mercuriell]

I'm thinking a light oil for the first few flights to allow tooth profiling and then maybe a nano lubricant such as the DiamondLube, it actually does seem to work! Was sceptical about the hype at first.

At least the full fuze helps keep the dust out so nice clean gears and red sticky goop may well be the best option

[darryltarr]

Correct, I did use Gerd's lube for the first two flights, my gears seem nicely meshed now. I will definitely source some Diamond Lube should the red grease provide less than expected results. Thanks

[TommyBear]

Darryl,

I've been using LLL for a while now on my "land based Jetski". 100% natural Lanolin based and seems to work very well on high stressed and high temperature application at sea level. I might try it on DS once #18 has devoured all of Gerd's supplied lubricant.


What are your thoughts on Mobil 1 SAE 0-40W alternative?

Lynh

[Mercuriell]

I use a lanolin based lubricant for my outdoor garden tools and it's great on the chain saws!

Wouldn't be comfortable with its ability to stand high pressure meshing loads in a gear train though and although I guess some might be excited by its sheep aroma I find it a bit smelly!