Another Crankshaft Failure

Yes, it failed again. This time it twisted slightly which meant the pistons didn't reach top dead centre at the same time, and the central crank web was rotating eccentrically in the crank case. This also meant the valve timing had slipped and the pistons were just hitting the valves of one cylinder. Luckily no damage was done, and now I've decided to manufacture a one piece crankshaft and the material arrived this week. Its a good job I made the crank case with a bulge in both sides as I'm going to need that internal volume for the much larger two-part big ends of the conrods. The material is an alloy steel, EN16T which is a tough steel, good with torsional strength. The down side of all this is that (as I mentioned earlier) I have to make two new conrods with a split big end and a split bearing. This bearing is made by soft soldering two pieces of phosphor bronze together and turning the bearing as one piece, then heating it up to melt the solder to form the two big end shells.

To give you an idea of the size, the cutter in the photo is 6.0mm diameter.

Crankshaft during remanufacture

Best day for flying so far this year

Wall to wall hazy sunshine and light winds from the East. I thought it best to go today as the weather for tomorrow (Sunday) is breezy. Took the Pico-Jet, Sunbeam and the Yak and actually plucked up the courage to fly it. Had an engine cut shortly after take off, despite extensive pre-flight testing. The next flight was OK, but I had to stop to video this:-

Ians F16 is always an impressive display.

Two flights with each aircraft today, and I brought them all home in one piece - a very satisfying day.

No April Fool

So this blog is about yesterday. (Wednesday 31st March 2010).


I've managed to re-assemble the KT120fsT and fit it to the fuselage of the Ultimate. I packed it all into the car and took it to work because at 19:00hrs the factory hooter goes off and I shout "Yaba Daba Doo"! (Flintstones connection) and then its time for a quick sprint over to the George Inn at Middlezoy to enter the Sedgemoor Clubs' Craftmans Cup. This is a chance to see what club members get up to in the cold dark Winter months.


A fine array of models had been built among them an Augusta helicopter, a Hawker Typhoon, a Corsair, and a Kyten. All very nicely finished, and of course its good to get together and have a natter.

2010 to be engraved

The Craftmans Cup 2007

Ketro KT54fs

The Craftmans Cup 2010
Ketro KT120fsT

Right! Whats next? How about a KTxxxfs7R? Hmmm, maybe??? What do you think?