IRON OXIDE

Iron Oxide, that’s right, to the rest of us its better known as rust, that’s my problem, rust and Super Tigre engines, a match made in heaven, or as I Have seen, a match made in hell, read on.

The problem began about four months after purchasing my Super Tigre 51 ring, up until this point it seemed fine and performed without fail, so well I added a tuned pipe to get every ounce of power out of it, and yet again, it was fine. Following an unintended meeting with the ground (this one's better known as a crash!) the engine had to be dismantled to check no soil had entered the engine, which wasn't that bad, the aircraft, an Avicraft Frantic had the crash damage repaired and all seemed set for me to go crash it again the next day.

But that plan met with a problem, The crankshaft, rear bearing and cylinder liner were rusty, to get to the state it was in the engine should have been in water so long it should have had several families of barnacles living on it !!!

At first the fuel, Helimix 5% with 13% oil came into question but we were not alone, as Mark Gregory another club member who runs his 4 Super Tigres on duraglo straight - the recommended fuel has had the same problem.

Next was it the methanol in the fuel which when left in the engine after flying attracts moisture out of the air which along with the residue left in the tuned pipe that could run back into the engine when the model is stored possibly making a corrosive goo, but I changed the way I stored the model and the problem still continued.

Our only theory to date is the oil in the fuel, which is primarily E.D.L, is so thin it runs off the surfaces, leaving them dry and unprotected.

A Similar reaction also has been seen to occur on engines run on the recommended fuel, with a standard exhaust, stored on their tails with the exhausts pointing downwards.

My father has been in contact with Model Technics to see if they can shed any light on the problem but all they could suggest was to use loads of after run oil, in my mind a very messy solution and also one we have tried without much success.

The engine manufacturers suggest stopping the engine by pulling off the fuel pipe while the engine is running fast to clear any fuel from the engine, This I have found is not always possible or safe to do. I have tried a variation on this by trying to run out of fuel on the last flight of the day although this doesn’t seem to stop the corrosion either.

We have not come up with a cure yet.

do you suffer from the same problem ? Do you have a cure?

if so please send your suggestions to the newsletter editor: Dave.

Matthew Harrison


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