Conrods

The fixture I made earlier for machining the conrods is very successful.

Just the thickness and central section left to machine. To give you an idea of the actual size, the bores are 28.5mm between centres. Next is to turn up the phosphor bronze bearings and press fit them into the bores. I'll warm up the aluminium first to ensure a tight fit. Then I'll finish bore the holes to 6mm dia. to suit the crankshaft and the other end to 5mm dia. to fit the gudgeon pin.

A last minute decision

The weather forecast for today was really poor, and it turned out to be pretty good, so I took the decision, bit the bullet, grasped the nettle, and went flying. The wind was from the South at around 6mph and later increased to 10mph. Its what I consider the limit for comfortable flying. Later still it decreased to almost zero, and stayed like that for most of the day.

I took both trainers, ended up flying only one of them, but thats OK by me, though I wished I'd brought the Yak.

Crowded...

It was worth going today, as Ian turned up and flew his Excelsior and F15. Spectacular.

Ians Excelsior




Ians F15 - Sorry about the quality, it was recorded on a mobile phone.

This Also flew this afternoon, powered by twin Irvine 30s.

There'll be no flying this weekend. Have you seen the weather forecast?

High winds and horizontal rain, sleet and hail. Just as well, I can get on with my engineering project. Today I've made a fixture to hold various sizes of conrod and I've set it up on the rotary table to machine one of the conrods for the KT120fst.

For the conrod I'm currently making, a 6mm dowell is required to locate one end on the centre line. For the other end a dowell with a 10mm diameter is used to locate in the slot of the fixture and a 7mm diameter to locate in the big end of the conrod. So now I can machine various sizes of small end/big end/hole centre combinations.

Fixture for machining conrods

The process begins

...And I've made a start on machining a conrod.

...And I've finished the crankshaft...

Alignment and concentricity end to end is a lot better than expected.

More next time.

Its Sunday and guess what?...

...Its blowing a hooley. This is the first day for weeks where the weather has been too rough to fly in, and today is my only day off work. Oh well, its to the machine shop today. First job was to weld some extension tabs to the baffle plate on the inside of our multi fuel stove. It would occasionally fall down onto the hot coals and I'd have to let the fire go out before I could refit it. Hopefully this will stop this from happening.

Our multi fuel stove - repaired.

I've not done much to the engine over the last few weeks as I've been doing other things (Christmas etc.) however today I've had a go at the rear end of the crankshaft, and formed the shape of the counter weight. I still have to drill and tap the clearance hole and M3 thread for the grub screw, then this part will be finished.

First step is to set up for drilling 3mm holes to form the corner radii

Sorry, they're a bit out of focus - trying too hard to get the detail in.

This unusual clamping method was the best way I could devise to hold the part firmly enough to machine into the 3mm holes.

Using the unusual clamping method to mill the 109 degree angle set up using slip gauges.

Sorry about the focus.

Back from the Christmas holidays.

Trust you all had a great Christmas, and here's wishing you a Happy New Year. Check out my other blog to see what Lin and I were doing.

Yesterday I was in the machine shop and I fitted the present Lin gave me for Christmas to the Milling machine. I then proceded to set up for milling the other counter balance weight as I did on the front part of the crank shaft. I've only done the setting, I've not cut metal yet as there were some dimensions I needed which were omitted from the drawing.

Those dimensions have now been added to the drawing, but today I'm going flying. More later...

OK its now later, and a great afternoons flying. There was no-one there, and the weather was very dull and the temperature was 1.5C, but the wind was non existant, well maybe a slight air coming from the SW. I took the two Sunbeam Trainers and flew both. One distinctively flies better than the other and I can only put it down to the slots in one of the wings. They don't work. I've been meaning to cover them up for ages but I've not got round to it yet.