New design - 0.5cc model aircraft diesel maybe call it "the Gecko"

[edholly]

With a fascination for small diesels, and their ability to power really small model aircraft, there came the desire to design and build one from scratch. After some doodling, have come up with the design parameters using the time honoured principle of keep it simple.

I did build an ED Baby, but was disappointed in that, although it ran, it had little power and would only keep going for a matter of 6 to 10 seconds. I next built a .75cc ML Midge using some mods like shaft induction and LH threaded nose section and which runs really very nicely with more power than the piston port Midge I built some time ago.

So using these experiences, here is my doodling for this engine. This will be engine build No.13

Thoughts are on this bit of paper - settling on :-

bore/stroke square at 8.5mm
Exhaust timing 135 deg
transfer timing 100 deg
inlet can be anything as shaft intake - more than likely go for 130 deg 10 BTDC and 120 ATDC
crankcase 3 bits, main case, nose LH threaded into main case and rear cover also screwed in.
Cylinder screw into case body and muff screw to top of cylinder and 3 slit exhausts with 3 semi circle transfers.
Pressed in crankpin and steel conrod - plain bearing using alloy of the nosepiece .

Will be a couple of weeks before I make a start but this is my thinking so far. Still a lot of detail work to do, but this is the basic framework I will work around.

Anyone care to put it on CAD?

 

[edholly]

Managed to sneak some lathe time today, mainly to try out my new 5inch 4jaw self centring chuck and 300mm linear scale. Both were terrific, the linear scale used to great effect as a depth gauge.

Note the digital window has sticky tape over it to read the numbers clearly, and the sticky tape holds the plastic bag which protects it from fluid and swarf.

Here's a photo of the 1st stage of the crankcase done using these two bits of hardware, about 3.5 hours to here and it weighs 12 grams.

The drawing sort of follows the machining - this way I can get an idea of what it looks like before the next step. Upside-down engineering?

 

[goldstar31]

Somewhere in the early 1950's I had both a ED Baby .46 and Mills 75 and both worked impecably. I lost my .46 in a Mallard ( was it a Veron kit?) in the Irish Sea in mid November! It was either hyperthermia or the plane.
Being in 'digs' - not my own property, I was limited to building small stuff.

So I'm enjoying reading your exploits now. I was wondering whether people still build Vic Smeed designs. All our yestedays but I recall being in uniform with the son of Keelbuild kits of the Model Shop in Newcastle upon Tyne. Again, I recall being with the then young locomotive fireman who had driven a train full of burning sea mines out of Liverpool- before they exploded in the city! He flew a little Debuntante. Nice design.

Thanks for the memories of a more exciting world.

Norman

 

[compspecial]

The mallard was a Mercury kit, Goldstar.


Stew

 

[goldstar31]

And Thank you for the memory- ED Comp Special?


Kind regards

Norman

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Will drop you a note re tugs etc

N

 

[hussien95]

nice work