Mamselle by Vic Smead

Ive had Mamselle for a couple of years ,she tried to elope with a lost Eagle but I found her.She tried to commit suicide by throwing herslf in a pond but just floated on top.and a wlker helped me retrieve her.Havent flown her since.The story is this.Ive lost a hose for my cleaning machine.In moving stuff around I put my hands on Mamselle.As is my lust I turned the prop,funny,no compression,nothing.Well blow the cleaning and the hose.must look see.Downstairs in the lounge and remove the engine.take the back plate off and there is the problem.\the gudgeon pin has snapped in half and is laying there.Took the head off.Piston is smooth in the liner,no marks its all perfect,so how has this happened.Is this what happens when a model gets a broken heart,I will soon have her mended.

Not as easy a fix as I hoped.I had another defunct thunder tiger engine not a 15 bt a 35 and the gudgeon pil is much bigger ,possibly drill the piston,just waiting a call back

Sussex Models think they can supply one,its all a bit strange as Im convinced its broken when not running.

Was it running when it tried to be a float plane?
The prop would stop very quickly in contact with water.
Maybe in your concern about a soggy airframe you did not actually turn the engine over before putting it away.

I would have to agree shearing a gudgeon pin is unusual, normally the con rod bends before that happens, maybe it was already cracked.
What does the break look like? A fatigue crack leaves a distinctive pattern.

No the engine had stopped and didnt get wet.Its beautifully clean inside not a mark anywhere

The gudgeon pin connecting the piston to the con rod.I cant figure it out,the pin was laying by the side of the conrod,how did it fall out,must have been pulled from the centre of the piston but there isnt a mark on anything else

Maybe that is why it stopped in the first place.

THe model ran out of fuel and landed itself ,the engine was fine then.Its been tucked away since.It is in perfect condition apart from the gudgeon pin snapped in half in the middle,its a mystery.There are no small plastic end pieces,like on the engine I stripped .I stripped a 25 hoping the pins would be the same but its a fair bit larger.

Now your wondering why it landed itself.It was hand launched by a collegue who switched it off has he let it go.Thats was why the take off was perfect,I wasnt in control.We watched it go up and up in circles until the engine ran out of fuel .I then followed it as the wind took it away.

Ive inspected everything carefully now and I think it must have happened in the air.The most obvious sign is the conrod ,the hole is oblong and worn with a shoulder.The piston looks fine but I think I need an engine.

No the piston pushed out easily ,and as I say the only visible mark is on the conrod where the gudgeon pin hole is oval and has s burred edge.