D H Gipsy mk1

Cut some alloy blanks for the Cyl heads

Turned the combustion chambers on the lathe then moved to the mill to drill and cut the valve seats.

Cutting the fins was more problematic than the barrels, I found it better to use no fluid and to cut in the same direction as the saw , 'climb cutting'

Removing more material to form the top shape

Tapping the plug holes, the digital gauge has proved very useful since I purchased it.

Finished Cyl head , I made five so one spare.

David

Many thanks for the reply.

I occasionally look at models of Gipsy Mk.1 engine at show and think that it may be an interesting model to make. When I start a model I always think that it will be a quick build, it never is. Now on my fourth model I am beginning to understand castings:

1. The aluminium used in alloy casts is always nasty to machine
2. I have yet to experience chilled, hard, cast iron but I know that it is a topic of conversation
3. The quality of the casting is always variable, usually poor
4. One has to be careful when setting out the initial datums.

I did have a quick look at a sectioned Gipsy Mk.1 engine this morning. Major Halford was one of the great aero-engine designers and the only one that progressed from piston engines to jets.

I wish you good progress with the model.

JA

Hi David,

I'd be interested to know where you found errors in the drawings. I believe I have found some errors in the camshaft drawing and am redrawing this part in CAD. Also don't buy 10T 32DP gears for parts 151/147 (as I did) without checking the dimensions first.

Regards,

Clive

Hi Clive, I have not got the advantage of using CAD, I will learn one day , so I just tend to trust the drawing and get on with it. The length of the valves gave me a problem , I had to make some more about 2 tenths longer.

Already bought the oil pump gears and fitted them , seemed ok and camshaft is made and fitted.

I have not written down any errors , nothing major just a couple of figures written down with the decimal point in the wrong place ie. 0.12 instead of 0.012 .

This was just posted over on MEM forum, makes a change to the usual stand and prop though it is shown with a prop at the end.

Hi David, Thanks for your reply. After a little head scratching I'm now happy with the dimensions given in the original camshaft drawing, so that's good and now it's time to cut some more metal.

I mentioned the gears as I couldn't locate a 10T 32DP gear with 0.375" OD as specified. I could only find a 9T gear with this OD and corresponding PCD.

Looking forward to the next update on your build.

Regards,

Clive

Hi Clive ,, yes your correct , I have just checked my oil pump and they are 9T Gears.

Bought my gears from HPC Gears 

Edited By David K on 08/03/2020 19:45:24

That's ace Jason, always someone who goes one better.

What a work of art ! Do they run inverted and if so how do you stop the lube oil from gathering in the back of the piston ? Asked this question at RAF Cosford, but no one could tell me. Many thanks Noel

The answer is you live with it. Mags off and a couple of careful pulls through on the prop before you try to start it. An experienced person would know by the feel of it that all was well or not so. Starting on a cold morning was often far from easy, all part of the fun. What you wouldn't want to hand swing was a metal Fairey prop , tough on the hands.

Turned some valve guides

I turned the valves a section at a time to help minimise flex in the material

Once complete a fine skim and polish before parting off

Valves complete with collets and caps , springs were bought items.

Inlet manifold , started with a piece of solid stainless

Machined the shape out on the mill

Turned the inlet stubs

Then finished them on the mill

Made a jig to hold the stubs ready for Silver solder

Then soldered in the bottom plate ,

I soak in citric acid and then polish

Started to mill out the end casing

Boring the oil pump

Silver soldered the oil pump gear to the drive shaft

Tapping for the inlet/outlet unions

The end case and parts ready for trial fit

Turned some brass parts to make the oil line unions

Silver soldered the parts

Made a jig to join the unions

Some extra pipe work

Made some union bolts

Milling the hex

A quick polish

Fitted to the engine

Made some union bolts

Milling the hex

A quick polish

Fitted to the engine

Impressive work and rapid progress!

Neil