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This week I made the cylinder liners and fitted them in the barrels. Only pistons and intake manifold still to do. Jos

Seems a French car gearbox to me (Peugeot/Citroen). I had a Citroen and its gearbox looked very similar to this one , the gear upper left is the diff gear. You should remove the gear selector rods first. It seems to me that the solution for the dissasembly lies in the opposite side of the...

I made the rockers but I was not satisfied with them. The pushrods were not perpendicular to the crankcase which meant that there were transversal loads on both rockers and cam followers. This problem was solved by new rockers with offset tappets. The pictures below show the difference between...

Nice project Ken! Do you intend to fly it on a R/C plane? I'm building a boxer twin to fly it on a R/C Demoiselle but it's not anywhere near a scale Darraq. I'll be following this build with great interest. Jos

Dummy cam complete.... .. and test fitted in the crankcase.

Between centres.... Machining....

Being inspired by Brian Rupnow's radiused cam design I made a jig to machine the cam lobes of my camshaft. Now this is a rather tiny part so I made a tool from a piece of tube with a cutaway section. End pieces in the jig are used to fit the shaft which is held in place by Allen bolts acting...

I made a start with the camshaft.First I made a dummy shaft from aluminium for test fitting in the crankcase in order to verify dimensions and to practise machining of the cam lobes.

Yes the contact pad is silver steel ( a.k..a. drill rod) circular shaped at the contact end, hardened and fitted with a light press fit and epoxy. The set scew is ball shaped, the push rod ends will have ball shaped hollow ends ( yet to be made). Jos

Been busy fabricating valves, retainers, rockers, the works...

Thank you Brian. Progress of this build is slowly but steady... I bolted all parts together that are ready so far to see what it will look like. Well, it looks like this: Next to make are the internals, cam gear, pistons, etc. Jos

I may be wrong but post #219 and # 220 are about a 4-cyl. boxer engine where this thread is about the 5-cyl. Ohrndorf radial. Maybe an error? Jos

I agree with Steamchick that brass is not the material of choice for rocker arms on this engine. The Edwards design specifies 7075 aluminium but Forest Edwards designed his engine to be a workhorse on an RC plane. It seems to me that longevity is not important with this engine ( bearing in mind...

Hi Peter, I bent the pipe by hand because I did anneal it . The pipe came out of my "stock" , it is just ordinary plumbing quality copper. The only special thing about this is that the original dimensions were 8 x 6 mm which I found a bit heavy. So I turned the OD down to 7 mm which, apart...

My favorite book on IC engines is Internal Fire, written by Lyle Cummins, the son of the founder of the Cummins diesel engine manufacturer. Published by the Society of Automotive Engineers SAE ( yes, the same who established the viscosity standards). In this book, the development of, and the...

Hi Ray, I notice that you use a 4 hole pattern for the head bolts. The original head has 5 bolts . Doesn't that give problems when fitting the rocker arm supports? Jos

Nowadays diesel engines for light aircraft are becoming more common with the declining availability of AVGAS in the Netherlands. Since diesel engines run well on Jet A1 fuel this is a solution , apart from the better fuel economy, where re-fueling of petrol- driven aircraft is a problem. One...

I did some milling on the crankcase, mainly for weight reduction purposes.

Most - if not all - commercial model 4-stroke engines rely on blow-by lubrication which means that two-stroke fuel with about 20% oil is used. Since there is always an amount of oil leaking past the piston to the crankcase this provides enough lubrication for the conrod and timing gear. I...

Today I finished the cylinder barrels. Cooling fin cutting is a tedious job but the result is nice. I used a mandrel for cutting the cooling fins so I did not need to clamp the barre in the chuck on the already machined fins. I used the mandrel earlier for the Edwards barrels.