Bentley BR2 Question

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Well-Known Member
Aug 15, 2014
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regina canada
Plans say to mount master rod secure ie silver solder. Cant wrap my head around how that will work so has anyone done it?
Which plans? I recently bought the L.K. Blackmore book (haven't built it) and in it the master rod is built up by pinning and silver soldered the rod to the central "hub". He does use the term "master rod" loosely for both the final assembly and for the main fixed rod that is assembled to the central hub to make up the final "master rod" assembly.
I have been working on the BR2 for about two years. I have not built the master rod assembly yet but I intend to pin the master rod to the hub and use loctite to secure it. The Blackmore book suggests loctite as an alternative to soldering. I feel like the loctite approach has less risk as it can be easily heated to release it if anything moves while setting it up.

I found this picture sequence helpful in my planning.
It is paramount that the Master rod, number # 1 cylinder does not come loose. In my case, using Blackmore`s book I thought I would be smart and did not follow the instructions fully and after a number of runs it came loose.
I stripped it down and my notes indicate I silversoldered it to place. Couple of things to note . Ensure the adjacent rods to the master rod [which does not pivot during operation] have clearance around their top radii to clear the 'V' section of the master rod, thereby allowing them to swing freely. clearances are fairly close in this area.
Hope this clarifies your concern.
Beautiful pictures, thanks for providing link. Who is the builder if I may ask?

I believe the pictures are from the build of Paul Knapp (I may be wrong, I don't know for sure). The Craftsmanship Museum has additional photos of his BR2 and other works of his. His work is impressive to say the least.

I saw this in one of the photos. It's such a nice build & even an RC model to go with it.


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My Gnome, built from Stephens plans has a quite simmilar rod. The master rod lies on the inside of the ring. The pins I used are DIN 6325 Passstifte (I think the correct translation is "dowel pin"?) No loctite needed. It has ben run about 8 hours is in the last years, without any problems.

I saw this in one of the photos. It's such a nice build & even an RC model to go with it.

I never thought to zoom on the picture of the write up. It's nice to know who did the build. Thanks for sharing it.
I guess it will work just could not visualize how


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When I built my Bentley I silver solder the master rod in the banjo and it failed. W I failed it broke one of the slave rods. When I made the second one I tig welded the master

I think all radial engines ( exept maybe the Anzani) use the one-piece master rod approach. I can't think why it should be different with rotary engines.

this message is for mick knights - i followed your article on building the bentley br2 in model engineer and it was very helpful - my problem is with the
ignition gear assy page 206 in hodgsons build - the drawings are lacking information on how to build the cam and in your article you made no mention - could you elaborate on this and possible describe in detail exactly what is to be performed - thanks in advance - fred eisner