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OK now had about 25 minutes running - so tried a max power run with the 7 x 5 wood prop - got rock steady 6900. Put the prop on the trusty Merlin in the Tomboy where it has had over 500 flights with an engine run of around 1.5 minutes, and it was well used before that, and it ran to 7,500. So...

Here's engine build No.12 - this time a modified Midge. Mods are LH thread screw on nose ball bearing inside two wider exhausts around 300% orig size enhanced transfer ports both in passages placement and size front rotary induction with conservative timing steel very thin wall contra piston...

Since using this process I have been able to size a cast iron piston diameter exact to less than a tenth of a thou. Found this process simpler and even more accurate than lapping. Bring the diameter down to 2 to 3 thou oversize with normal machining. Cut a couple of strips of wet and dry (or...

Hi Don, Absolutely beautiful work on your Mate and I see you hogged yours out of a solid lump too. You must have been very pleased to see it run to those revs. For a first Aero engine, you certainly not only chose well, but did the design proud. The casting was done by Camcast not far from...

Often a taper is required in a piece, sometimes just a thou or two like in a contra piston. You can check this BEFORE MACHINING by moving the compound slide the length of the cut and gently bringing the cross slide against the piece. The difference in the measurements is the taper. Since using...

Rather than use a dial gauge, you can check the run-out of a piece in the lathe by using the cross slide. Bring the cross slide with whatever tool it has gently up to the piece for each of the 3 (or 4) jaws and note the reading. When the reading is the same for all 3 (or 4) jaws, the piece is...

To get a really nice point or a very nice radius on the end of a wire say for a needle valve, or a nice radius on the end of a gudgeon pin, put the piece in the end of a drill and spin it up against a linishing belt which is also turning. The point or radius comes out very nicely plumb in the...

When finding the centre of something on the mill with DRO - I always move the spindle through 180 degrees from one side to the other. This then does not matter if there is an error anywhere in the devices, it simply cancels the error by doing this. Similarly - if finding an edge, I always double...

I hope this thread develops where simple practices we all stumble across, by necessity or otherwise, are listed for others to consider. Hopefully the posts will be brief, maybe just a couple of paragraphs at most - and one post dedicated per practice. Please make the posts in a colour, so that...

Have had a chance now to run some back to back tests ... all with a Turnigy 9 x 4 wood prop. These are a very wide paddle blade almost type of prop - I think a nylon or glass/carbon fibre one would run more revs. Original Owen Mate has now had about 75 minutes running ... 8400 Owen Mate...

Rich, .... Thanks ... Dave, .... The housing is not different to any bolt on one. All the bearings are a part of the removable part so the only loss of concentricity is if the mating surfaces were not square, which would be the same problem if a bolt on. The thread itself is tight enough when...

After making an ML Midge some time ago - and then a Vee Twin based on the Midge - thought I'd make another but try something a bit different. Last engine built was an Owen mate with a removable front nose, cap-screwed on. Now making a removable nose sure does simplify things, and the thought...

Went to the Oily Hand weekend at the Cowra Model Aero Club on the western plains of NSW Australia where you were only allowed diesels (or glo up to 1cc) for most events. All engines had to be UN-muffled so plenty of noise just like when I was a kid at Centenial Park in the heart of Sydney's...

Having just finished an ED Baby, which with its tininess meant it wasn't that pleasant to build, especially when it ran but not well, I needed something I could enjoy building just for the fun of it. So I set myself a challenge - build an engine in under a week and under 40 hours. Well it...

The Baby was finished some time ago - and it did run but not well. Bursts of about 10 seconds max then cutout. Has reasonable compression, so suspect my needle valve production is to blame, power output very poor. There's a short video of it running on the RCGroups.com website and you can see...

This is my 10th engine now - and I think this one is the most intolerant of any little errors. Have the crankcase finished and the backplate along with the muff. The muff is a bit taller than planned, my first cut for a fin was 40thou above where it should have been, I measured from the...

I note that Ron Chernich was the last person to do a post on this thread, how I miss Ron and his wonderful ModelEngineNews every month as I am sure a lot of us do. RIP Ron. It has been a while since I had the casting made for the Baby and have been busy since then going down the twin cylinder...

Here's a way I just used to transfer a gasket outline onto a card. Using a Pentel Permanent Marker pen - or a Texta would do, coated the body O wanted to transfer with the ink from the pen. Of course it dries too quick to use - so hit the card with a bit of carby cleaner - or ant fast drying...

Today I transposed the cylinder/piston/muff/conrod assemblies from front to back and vice versa - by doing this I was able to ascertain what 150 degree inlet porting would do to the running of the engine, as I had erred originally by making the inlet holes at this spec, before making more...

Just ran it again now - 2 days later - no change to settings from then - 3rd flick - consistent 5600 on the 7 x 5. What a difference that cylinder/piston combo makes ... from a non-runner to a beauty ! .:)