Author Topic: Doug Kelly - Bruce Macbeth Engine  (Read 1009 times)

Offline Trevorc

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Doug Kelly - Bruce Macbeth Engine
« on: July 06, 2021, 06:54:42 PM »
Hello, i have recently obtained a copy of Doug's book. I do not know if he is still an active modeller or member of this forum. Can anybody advise please.
I am considering the  Macbeth engine as my next project once i get my Anzani running and demands of the summer garden reduce somewhat.
Are drawings for this engine available, the drawings in the book are rather cramped hence details are not clear. Also is it a successful engine i.e does it work? Are there any hidden challenges not apparent from first look at drawings?
The design of the crankcase uses a lot of expensive brass, does anybody have a view why Bruce choose this material other than it might be a bit easier to silver solder.
Any views and opinions would be gratefully appreciated.
Thank you.  Trevorc

Offline sid pileski

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Re: Doug Kelly - Bruce Macbeth Engine
« Reply #1 on: July 06, 2021, 07:59:00 PM »
A friend of mine is building this engine. I modeled it in CAD for him. One of the major changes I made was to make the base out of aluminum to simplify the building process greatly. If I recall, Doug soldered everything together, and then went back and machined the base to square it up where needed.

I met Doug at Cabin Fever at the last one, two years ago. This engine an his others were all running there. There was another fine example of one running too.

It's a nice engine to build. We made other variations too. Mainly in head contruction), but essentially followed Doug's plans.

Sid

Offline FKreider

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Re: Doug Kelly - Bruce Macbeth Engine
« Reply #2 on: September 17, 2021, 02:08:09 AM »
If you follow Doug's plans then the engine will run beautifully - as Sid mentioned I have also seen several examples running in person at the cabin fever show.

No full size plans are available - the book is the only source for the drawings. If you have trouble with the small print I would suggest using a photocopy machine to make enlarged copies for your own personal workshop use - this way you will also not get the book dirty/oily out in the shop. Just my 2cents.
-Frank K.

 

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