# Bentley BR2



## joerom (Nov 28, 2018)

Hello to all,
    I was away from this hobby for quite a while..I am 73 now and decided I needed to play again..I came across a partly built Bentley BR2, well actually 2 of them..They were being made in 1/3 scale..It appeared that there was quite a bit of work already done, and it looked pretty good..When I received them and started going over everything, I started to see that there were many things that did not suit me and some things left me puzzled as to the original builders intentions..The first thing that I realized is that the 1/3 scale did not follow through, and as an example, the crankshaft was short as to what it should be for the scale, and then the main mount was nothing like what a BR2 should look like..


   OK, there is a brief summary of why I am doing what I am doing..I want to bring it closer to scale, and will change what I think necessary to do so..I will post pics as I go and will start with a comparison of the way it was and the way it will be..On the left is the way it was..Disregard the date,never setup camera..



 In the first picture above, you will see that the crankcase was much thicker than what it should have been..There was plenty of metal, so I was able to narrow it by .400 total..It made a big difference in the look already, because it also tapered it up from the front and rear cover, look at the pics..





The above picture gives a rough idea of what I wanted to do....




I had to re-taper it to meet the cylinder ..




You can see how it changed it making it much closer to what it should be..
That is a good start for now, and I will explain all other changes including making the main mount look like a BR2...….Joe


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## rweber (Nov 29, 2018)

Do you have plans on which you are working, or is it all own design?


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## joerom (Nov 29, 2018)

Hello,
   There are plans available for the 1/4 scale version..There is also a book..I believe there are some on ebay now, just type in Bentley BR2..The plans are available in England somewhere, and do a search for the same..I am just scaling up the available plans, plus making changes necessary on my own to meet the scale engine that I want...…
                                             Joe


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## rweber (Nov 29, 2018)

For your information, in ME Issue 4589 started a series of articles where someone builds a BR2 composed with the best of both plans, the Blackmore book and the plans from ageless engines.


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## 58tux (Nov 29, 2018)

Joe
  Having built a 1/4 scale Bentley I know that there will be several challenges especially changing the scale of the engine and starting with someone else's work.  I will be following your work.  There will be no thrill like when you first hear and see the engine run.
Rich


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## joerom (Nov 29, 2018)

Hi Rich,
   That looks like some very nice work..I can really appreciate what is involved with anyone who takes this thing on..I have done a few projects in my time, and some very involved..When I took on this project, I did not realize how far from scale it was until I received it..What I am trying to do is get it as close to scale as possible with what I have to work with..I have 2 of them, and my thought was to make two of everything and finish both engines..In reality, that is not going to happen, because there is too much changing to do to make it more scale than originally thought, and I am 73 and have more projects I want to finish....So, I will concentrate on only the one for now..I have it much further than what is shown here, and I will post much more here..Later on today, I will add more info here of my progress...
                                                                      Joe


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## joerom (Nov 29, 2018)

The next thing I had to do after thinning down the crankcase was to shorten the front crankshaft extension or Maneton, which is what the master rod rides on..Fortunately for me, the previous builder had threaded the part I needed to machine into the extension..It took me a while to figure that out because it was done so well..In the following picture I am machining to length the part, and then followed by having to match the taper in it to fit back on the main crankshaft..That all went well..






Then after doing that, I had to match the master rod which rides on the maneton to the maneton..This was machined on both sides to a depth needed..It was also figured to match the 2 ball bearings that will go into it in a special carrier..




In the following picture, you can see the master rod as it will sit in the crankcase..It is waiting for the bearings and carrier to be made..


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## joerom (Nov 30, 2018)

Hello again Rich,58tux,
    I am curious as to what you did for the elbow's on the intake on your 1/4 scale engine..
                                                  Joe


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## HWF (Nov 30, 2018)

Joe,
I am very happy to see an active thread on building the BR2.  I am planning to build one as well.  I have the 1/3 scale plans from Ageless Engines and the Blackmore book.

I have opted to go with the 1/4 scale which more closely follows the actual engine design.  I have been modeling the engine in 3D CAD with the intention of CNC machining the parts.  I have just started working on the CAM programming of the first part.

I have a grandson who is coming up on his first birthday in Dec.  His name is Bentley which is what got me thinking about this project.  I have found someone at an RC club in Georgia where my grandson lives, that is willing to build an RC plan to house the engine.

So I look forward to following this thread and exchanging notes.

I am planning to make the elbows from a solid billet on the CNC mill.

I hope that I am up to the task and hope that mine turns out as nice as Rich's.

The Ageless Engine design seemed to be focused on ease of fabrication rather than authenticity.  A lot of the parts that were originally made from steel were made from aluminum in the Ageless Engine design and I would be concerned about putting that engine into an RC model.  The 1/3 scale would also be a major issue.

Rich, I am curious, the Blackmore book calls for the use of a lot of mild steel for his engine where I would have thought that stainless would have been more appropriate.  There seemed to be some amount of compromise to enable manual machining with small home shop machines.  What materials did you use and what equipment did you use for fabrication?

Howard


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## joerom (Nov 30, 2018)

Hello Howard,
    I am happy to exchange notes or whatever to anyone attempting to build this or any engine..We are always learning..I am also thinking about CNC for the elbows, and am just starting to get together a machine to do it..I am more use to doing the hard way though, and still may do so..To me, it was always the challenge to see what I can do, and the more difficult the challenge, the more interested I become..
    Although mine will not be full scale as the Blackmore book because of what I am starting with, I will make it as close to scale looking as I can..One thing we all need to keep in mind is that this is a hobby, and what ever anyone does that is to his liking, is all good...So, do what makes you happy.....
                                                                                        Joe


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## HWF (Nov 30, 2018)

Joe,
I can agree more.  For me it is all about learning new things.  There is lots to learn.
For me it all the ins and outs of my CAD and CAM software as well as my new CNC controller and mill.

It is always good to have a project to help you push your limits.
Howard


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## 58tux (Nov 30, 2018)

Joe

The intake manifolds were the most challenging parts of the engine to make.  The upper elbows I cast following the instructions in the Lew Blackmore book.  I Must have cast 20 to 30 pieces before I got nine good ones.  I discovered that I do not know anything about casting Al.  The lower pieces I machined from the solid.  When I built the Bentley I did not have any CNC capability.  Also there is no stainless steel in the engine.  The heads and cylinder liners are 12L14 steel.  The cams and cam rings are 4140.  The rest of the engine was made from what I had laying around, mostly 1018.


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## joerom (Nov 30, 2018)

Hi Rich,
   You should be proud of what you have done..The work looks great..I don't know if anyone ever made castings commercially for it, but it would seem like a good idea, although it would not help me in my scale....


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## joerom (Nov 30, 2018)

Now I am going on to make the main mount..The one the original builder made does not look like a BR2 mount..I needed to find gears to fit in a certain space with the correct ratio to keep it looking like I wanted..I finally found a set of gears that would work for me, and there is just enough room in the main mount for them to keep the outside looking right..I first machined the inside just enough to fit the gears and have them rotate with each other..The gears still need to be modified later to mount them..The following picture shows this...



I then proceeded to machine it to shape inside and out..The three small holes you see in the mount are for the two magnetos and oil pump that will be mounted later..They will need to be opened up to the size needed..They are only there now to get the centerlines for the gears for mesh..The following picture shows the mount, which now looks like a BR2 mount..It still needs some finish work and holes.. 



The next 2 pictures shows it mounted..The sleeve nut that holds it on is wrong and the crankshaft still needs to be extended..


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## kvom (Nov 30, 2018)

I have seen the Ageless engine version at various model shows over the years, and Lee claims it's "easy" to build.  haha

I would think aluminum for weight over steel would be an advantage if one were to try to fly the engine.  That said, since the engine itself rotates there will be a very considerable side force during climbs that the rudder would need to counteract.


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## joerom (Nov 30, 2018)

I have never seen the Ageless Engine version in person, but have looked at many pictures..I guess if you consider what the Blackmore version needs to construct, the Ageless Engines would be easier, but by no means easy.....
   A lot of mine was made with  aluminum, but I am not concerned with weight..I made the main mount with 12L14..Being 1/3 scale, that probably would not matter if in an airplane because the plane would be huge..I figure this one would have a 36" prop....


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## joerom (Nov 30, 2018)

kvom,
   What is your preference in all this stuff...


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## HWF (Dec 1, 2018)

Here is a video of the Blackmore version used in an RC model. When complete the 1/4 scale version of the Blackmore is about 16 lbs and will use a prop of about 27".  I have not seen any implementation of the Ageless version that has been used in an RC model.


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## joerom (Dec 2, 2018)

It would be really neat to fly an engine like this that you made, but I am not that brave..I have flown RC and also crashed some, so I can really appreciate someone doing that..It also shows that it has real power and is more than just a model and the craftsmanship of the builder....


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## Cogsy (Dec 2, 2018)

I feel the same way - I'd hate to see an engine with so many hours of building in it destroyed by something I couldn't control. I once lost an airframe that was less than 10 flights old when the aileron servo stopped responding mid-flight. I made it back to the field on the rudder but it dipped the left wing and I couldn't get it back so it went in hard. That servo still annoys me when I think about it - it didn't strip a gear, just failed electronically - but that airframe only took me maybe 75 hours to build, nothing like one of these engines.


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## joerom (Dec 2, 2018)

Having made the proper style main mount, it is looking more like a BR2..Next I needed a stand, and this also means I needed an extension for the crankshaft, and also a proper style sleeve nut that secures the main mount to the crankshaft..If you look at the picure below, you will see on the left, the new stand and extended crankshaft and longer proper looking sleeve nut..On the right is the original design that was made by the previous builder..The main mount is nothing like a BR2, and the very short sleeve nut looks wrong..NOTE: before I go any further I would like to say that the engine that  was being made by the original builder would have worked the way it was, it just would not have looked like a BR2 should, and as far as I am concerned, it would just have been a 9 cylinder rotary engine, and that is not what I was after..I was originally going to make 2 of everything and have 2 finished BR2's, but with all the figuring and changing that was necessary to do what I wanted, this would have been an even much longer project, and at being 73 years old, that idea seemed like it was lacking something...……





I fashioned an extension for the crankshaft that was threaded on to match the 40TPI..It was a sleeve that threaded on the crank after the newly fashioned sleevenut to secure the main mount..Notice the difference in the sleevenuts on the left and on the right in the above picture..I also then threaded the end of the extension that goes through the stand at the rear, onto which I made another nut to hold the rear of the engine to the rear of the stand...These are shown below..




So, with the addition of the previous parts, I think it looks like a proper Bentley BR2 now, as compared to what the original builder intended, and the following pictures show that...





















Moderators,I hope I am not adding too many images, as I do not know if there is a limit...…...


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## kvom (Dec 3, 2018)

More the merrier


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## RonC9876 (Dec 4, 2018)

I built mine in 1/8th scale. It is amazingly powerful for it's size. The only real problems were with the ignition. When first started it was equipped with spark ignition and it ran well until the rings seated and the compression came up. At that point, spark would jump externally everywhere but at the plugs. I tried all manner of insulation ideas and even thought of lowering the compression with shorter rods, pistons, or whatever to stop the external arcing. I finally decided to switch to glow ignition. This worked out well. The segmented commutator was replaced with one with slip rings and glow plugs were fabricated using elements from standard glow plugs welded into 5-40 diameter bodies. The engine can be seen running on YouTube at ronsmodelengines/BentleyBR2.


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## joerom (Dec 4, 2018)

Hello,
   I have seen this engine before and really liked the smaller size..Actually, I am an admirer of all your engines..I always check you out at Cabin Fever....
                                                                  Joe


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## RonC9876 (Dec 4, 2018)

Thanks, Joe. The quarter or now one third scale models are hard to transport to the shows. Especially when you have as many engines as I do!


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## joerom (Dec 9, 2018)

Although I am a long way from needing a carburetor, I wanted to see what it would look like with one because of that being another thing that would make it more like the BR2 I am looking for..So I did the basic carb, and it has no internals yet, and also needs some additional exterior finishing..The pictures below show this.. It is of proper size in and out, and now makes the engine even more BR2..When I first started this project of making this thing look like it should, I was not sure of the outcome, because it was so far from scale looking..The brass pipe lying on the bench by the stand will be mounted on the carb crosswise..This would have gone through the airplane and exited through the body..Now I am pretty pleased with what I have so far, and will continue along with all the boring work to follow..








 Next, I have squared off the holes for the intake pipes like they should be, and also mounted the main gear..I did not take any pics of this, but it was cut the center out of the purchased gear, and press it on, no magic there..




The last thing to do here was drill and tap for the cover on it, and that is done now...…..


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## 58tux (Dec 9, 2018)

Looks like you are making some great progress.  Keep up the good work.  Seeing these pictures I think that I will get my BR2 out and run it today.

Rich


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## joerom (Dec 13, 2018)

The next thing I wanted to do is to slim down the rods that were there..They had too much metal on them and you would not be able to install the rod assembly in the crankcase in one unit..You would have to assemble the rods in the case one at a time..I want to build it outside and then install it, hopefully..You can get an idea of what I am doing by looking at the picture below..The one on the left is as I got it, and the right one is trimmed some..The ends need to finished up a bit yet, and this is one of those boring jobs..There won't be much to show until I get some of this stuff done..After this is all done, I will make the bearing carrier for the master rod...


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## joerom (Dec 16, 2018)

I did remove some more metal overall from the rods, than in the last picture..This was because I just did not get the right numbers the first time..I also rounded the ends some more because of excess metal..Now all the rods are slimmer and even all around..I stuck them in them master rod to see what they look like..This is the first time I actually saw all the rods together as a unit..Next I will finally get to the bearing carrier for this..


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## stragenmitsuko (Dec 17, 2018)

amazing craftmanship


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## John Roberts (Dec 17, 2018)

I am also building a BR2 but based in the Blackmore design. I also first modelled the assembly in CAD as there are so many dimensional  errors in he Book.
I have completed the  crankcase, cambox ,thrustbox, nose piece and currently making the con rods.
I would be very interested in finding out what valve springs to use. I see that tapered ones are available but have no idea what wire size and general dims of this item. Any advice would be appreciated.
I hope to make the induction elbows from solid on my CNC mill but as yet having difficulty modelling these parts. Anyway I am a long way from making these.
Just made a slotting attachment for the lathe to tackle the key slots needed. Not sure how well it will work on steel.
Lots of challenges ahead!


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## joerom (Dec 17, 2018)

Hello John,
   The BR2 seems to be a popular model..If you are going the full scale route, I believe that the flat springs are explained in the book, and there are many pictures..I would think that there are ready made springs that can be used, and would involve some experimentation...I am making changes as I go..
  Mine is 1/3 scale, so any thing as far as sizes  and general dimensions would not apply..This is an ambitious project to say the least, but one of the better ones..
   Maybe another builder can add some info here as far as springs for the 1/4 scale version...……..


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## joerom (Dec 17, 2018)

An Observation,
    When I first took on this project, I was not too sure about the 1/3 scale..I originally wanted the 1/4 scale version..But, I went along with it because of that was what it was, and being 73, I figured this would be a quicker way to have a BR2..After working on this thing for a while now, I am realizing that it is actually easier to work in a larger scale engine..Although I am not saving  time by having a part built engine because of all the changes I am making, the changes seem easy mainly because of the size..I am actually liking the 1/3 scale now, so much so, that I already have my next project lined up, and that is a 1/3 scale Gipsy Major that was originally designed by Krieger..
   I do still very much like the smaller scale engines, but for me now, bigger is easier, probably because it is easier to see!


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## petertha (Dec 18, 2018)

Not to detract from your BR2 post, but is this the 'next project' you mentioned? You mean you have the castings or will scratch build from the design? Cant wait in either event.
http://modelengineeringwebsite.com/Gipsy_Major.html


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## joerom (Dec 18, 2018)

Yes, that is the engine..I have the castings, and I think it is a greatt looking engine, and a great scale project....
I  will start on it while I am working on the BR2, mainly to keep the interest up because my ambition levels are declining as I get older..I also have other projects, and will work on them also, and if I have a lot of unfinished projects, it does not matter, as long as it keeps me off the recliner..
 I will move to Engines From Castings when I start that project, even though it is also a long term project..Nothing saying I can't have 2 projects going(or maybe even more).……..


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## John Roberts (Dec 18, 2018)

I intend to stay true to the Blackmore design apart from the valve springs! There seem to be many others who have opted not to make their own from flat  spring steel. This looks like a hit and miss affair getting the hardening correct.
Tapered coil springs still look right in this engine.


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## joerom (Dec 18, 2018)

I agree with using the coil springs..There is enough to do on this engine without making scale springs..The flat springs look like they would be a lot of work to get right..You could also add them at a later time if you wanted..
   This is a hobby, so do what ever feels right to you...………………….


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## joerom (Dec 21, 2018)

I am now working on  the bearing carriers for the master rod, two are needed..In the first picture I am getting them to size..Then  once sized, they are cut off..The last picture shows how they will go and are just loosely placed...The bearings will press fit into them and they will be mounted with screws into the master rod once I finish them..They are a snug fit in the master rod...
   After that, I will finish the crankshaft by adding the oil line from the main mount to the main journal..I also need to add some oil lines because of what I changed to make this all work out how I wanted it to be..


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## lantain1982 (Dec 21, 2018)

Regarding valve springs on the Br2 [1/4scale]   I tried, without acceptable results to make the flat spring item.  I found it very difficult to obtain any form of consistant results, bearing in mind that the springs must collapse  fully to achieve full valve travel opening.  I switched to involute wire springs.  May not look as good but I accepted a practical solution.   For interest if you are looking for a source of flat strip, go to your local wrecker and obtain an old seat belt retractor, you will have enough strip to last a lifetime.   You will have to reduce the width to suit.
All the best with the BR2, when you fire it up for the first time its a moment you will remember.   
Cheers.


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## joerom (Dec 21, 2018)

I will go with regular springs to get this thing running, when the time comes..Maybe later, just for fun I may try the flat springs..I am the type, that the whole challenge is if I can do a certain project..Once the project is done, no matter what it is, I lose all interest and go on to the next project..The more difficult a project, the better I like it...
   I do like all thoughts and input on all your projects also, even if not directly related...


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## John Roberts (Dec 22, 2018)

Attached are some photos of  1/4 scale my master rod assembly. One can see the difference in construction. I chose to use  shielded bearings which I hope will be OK. 

Regarding the involute springs you used , do you have the specifications on these. That would be very helpful.
I have obtained some main spring which I may try to make , but don't hold much hope  getting a consistent hardness.


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## joerom (Dec 22, 2018)

John,
   I have not made my springs yet..Mine is the 1/3 scale one, and the springs would be very different..Have you tried to find something ready made that would be about what you think you need...
   My master rod was already made..I am just modifying it to do what I want it to do..As far as the bearing being shielded or not, I have seen engines using shielded and engines using not shielded, so I am not sure which would be better..I guess it is all an experiment..Also, I am going to try a different oil passage on the rod journals..Nothing is etched in stone on building an engine..You just do what you think may work best, and give it a try, because that is what this is all about anyway...…
   I just want everyone to be sure of understanding what I am doing..I purchased two part built engines that were representative of a BR2..I am in the process of trying to make one more closer to scale than was intended by the original builder, and in doing so, I am making major changes in a lot of things, and it may seem like I am building an engine......But, I am only doing this on one engine...………...


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## petertha (Dec 22, 2018)

The bearing shield is a good question. On RC engines its quite common to remove both shields for fully internal bearings or just leave the outer shield on an external facing bearing. But those engines typically have oil premix in the fuel so the coating is pretty much everywhere. I think another consideration is that the fuel can act as a solvent & rapidly dissolve the bearing grease anyways (probably creating more issues if it gets up into the glow plug). At least I think that's the case of methanol fueled engines. I haven't taken apart many gasoline model engines to know if they adopt this or to what degree.


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## joerom (Dec 22, 2018)

petertha,
  That is a great reply for what I have been saying, and that is just do what you may think will work, and see what will happen..I would bet that you would get three different replies from 3 different people..I have always listened, and then taken what I think I could use, and then did my own thing...It is all good...……………….


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## John Roberts (Dec 23, 2018)

Yes, grease getting flushed out by fuel mixture was also my thought. I may remove the shields in time.
More photos of my build to date.


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## 58tux (Dec 23, 2018)

John

Looks like you are making good progress.  Your work is bring back a lot of memories of when I built mine.

I used open bearings on my BR2.

Rich


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## joerom (Dec 28, 2018)

I am still here and working on the BR2..The things that I am doing now are just things to put everything back to normal because of all the changes I made..Things like relocating oil passages and finishing things that were either shortened or redone, re-tapping holes which would not lend to more pictures..I hope to soon get started on finishing the cams, and that would get back to doing pictures again..
   These engines are beautiful pieces of machinery, but when you have to make 9 of everything, it seems to take forever...……..


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## mayhugh1 (Dec 29, 2018)

joerom said:


> petertha,
> That is a great reply for what I have been saying, and that is just do what you may think will work, and see what will happen..I would bet that you would get three different replies from 3 different people..I have always listened, and then taken what I think I could use, and then did my own thing...It is all good...



I'll add the third reply. Another consideration is metal contamination in open bearings. As the engine 'wears in' and that includes the rings, there will be metal circulating (or, in the Bentley, suspended) in the oil, and the shields can help keep it out of the bearings. The engines we build with oil pumps seldom have oil filters, and so it's probably a goid idea to at least include a magnetic drain plug to capture the ferrous debris. - Terry


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## joerom (Dec 29, 2018)

My next project which will be the Gipsy Major, has an oil pump and filter included in the build..


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## HWF (Dec 29, 2018)

In the case of the BR2, the oil is not recirculated.  Hopefully the metal contaminants will be exhausted along with the spent fuel and oil.

I suspect that is was the intent of the original design that all of the parts be bathed in an oil fuel mixture which is why an oil that is not soluble in gasoline was used.

Therefore I would probably opt for unsealed bearings.


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## 58tux (Dec 29, 2018)

As far as using shielded or unshielded bearings it these models I do not think it makes much difference.  Most of the model we build do not get run for that many hours.  
I used all unshielded bearings in my BR2 except the front support bearing.
TBO for a BentleyBR2 was only 40 to 50 hours.

Terry, how much time do you have running your Merlin or your 18 cylinder radial?

Rich


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## petertha (Dec 29, 2018)

I think micro metal shrapnel is real. Some other RC specific factors I failed to elaborate on was

- shields, at least the more common urethane coated ones that always seem to correspond to our bearings, were considered a bit of extra drag on HP engines (real or imagined). Or at least if they were distorted & were not reinstalled properly. The front shield of front bearing is always left on. That's where runway crap always gets in. Or a 'deep loam massage' on an unlucky day LOL

- I suspect the bigger reason relates to proactive bearing maintenance. High grade methanol & probably nitro too are very hyrgoscopic which means rust. Many of the common synthetic oils in these fuels have a nasty habit of creating acids, so even more corrosion. You can see stained metal where a small puddle line of unspent fuel was in the crankcase within a week. It is very common to liberally add after run oil through the plug(s) & carb & turn over the prop. Then always drain before starting the engine so do chance of hydraulic lock given the low squish clearance. People have their own recipes, but for winter storage especially in humid climate, the engine is liberally coated with something like pneumatic oil & stored in a ziplock. Looks kind of like an oily marinating steak but it does work. The other thing is (at least in HP circles) usually you don't wait for a bearing to growl, because any scoring that occurs on the (ringless) piston liner usually means bye-bye power or worse. Bearing replacement is cheap by comparison so its common to just pull them after X runs.


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## joerom (Dec 29, 2018)

Back to machining..I did start on the cams for the BR2..In the  picture below , that is what I received with the engine minus a few holes..The cams were also not sized for thickness..




 I next trimmed the inside of the ring gears below..They are still oversize, and they will be finished when the cam gears are done..





The next thing I did was to machine the one side of the cam gear for the tappets, shown below as it was being done...





And this is how it looks after finishing that operation...




Next I removed the excess metal from the cam gear below, and down to the right thickness.This is as far as I got and I need to finish the gears yet, and that is for another day...….


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## Cogsy (Dec 29, 2018)

If bearing damage from small contaminants is potentially an issue, you can buy 'hybrid' bearings that have one of the rolling elements replaced with a ceramic rolling element. These ceramics are far harder than the raceways and most contaminants as well. During operation, the ceramic roller/ball will somewhat self-repair the micro damage caused by contamination by flattening the raceway and crushing/ejecting the contaminant as well. So the bearing will have a far greater life in a dirty environment than a standard type. When I was in the bearing industry these hybrids were available for many of the common sizes (although primarily metric as the vast majority of the bearings produced and used around the globe are metric).


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## John Roberts (Dec 30, 2018)

Thanks to all that have commented on the bearing debate. Very interesting comments.
My engine is progressing slowly, currently making the Maniton shaft and crankshaft. I was pleased how my slot attachment worked. My intention is to screw the crankshaft into the crank and Loctite. Hopefully this will be strong enough and save me some tedious machining.


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## petertha (Dec 30, 2018)

Neat!
- what is the brass stem coming out of the slotting housing?
- is the slotting tool something like drill rod & you hardened the cutting edge?
- about how much do you progress the cutter every new stroke?


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## John Roberts (Dec 30, 2018)

The brass stem engages in a slot in the steel ram. The cutter was made from 8mm silver steel. Machined on the mill and hardened and tempered. The amount of stroke was about 0.001" each time. The slot was 2mm wide by 1mm deep in medium carbon steel.


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## John Roberts (Dec 30, 2018)

I mean depth of cut for each stroke!


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## joerom (Jan 3, 2019)

I am working on the cam gears again..The blanks that I got with the engine were not quite right for me, so I am making  new ones that suit me better..They look like the ones pictured above, just a slight change in diameter, so I did not bother to photograph..I want to finish up the cam gears and rings, and also the crankshaft, and there is nothing actually new to show, even though I am still working on it...………
    If I decide to do the other engine I have, I now know all the changes needed to make a more scale BR2 than what was originally intended, and it would be a lot easier to do so now...I think that it looks very much like a proper BR2 now, and at least for me, it is worth the extra work..The other way would have been to do it as it was, and I would have a rotary that looks loosely like a BR2, but with a lot less work..The machine work for the most part that had been done by the original builder was actually very good, I just don't think I would have been happy with that...….


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## 58tux (Jan 4, 2019)

Joe  A word of caution.  When you install the cam rings in the cam box, use a steel key.  I used a brass key the first time and then got to make a second set of cams and cam rings when the brass key failed.


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## joerom (Jan 4, 2019)

Hello,
   Thanks for the info, but I already have steel keyway stock..With being 1/3 scale, I am going heavier on everything that I can..
Did it mess up your engine bad..Things like that can really spoil your day..


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## joerom (Jan 5, 2019)

I am working on the cams still, and getting closer to being done..The pictures below show this..The cam rings were drilled and cut to tooth height on the lathe, and then the book suggests finishing by hand with a file..I used a Dremel and did it that way..You already have the proper spacing and height, so it is a simple matter to do the nose..I ended up doing the same for the cams, and it came out very well, and works smooth..The cam looks blotchy because I case hardened it and that is as far as I got with the cleaning..The eccentric still needs more drilling and keyway put in, as does the cam ring...…


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## joerom (Jan 12, 2019)

I wanted to make the top plate that holds the upper bearing on the eccentric shaft before I finished the upper cam..I needed to change it from the drawings because of the way this was being built in 1/3 scale by the original builder..So I decided I wanted to  make the top plate as an attachment to the front propeller housing..The very top of the plate is flush to the top of cam housing and will secure the cam plates in the final position..In the following pictures you will see what I mean...…


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## joerom (Jan 26, 2019)

I have done a little more on the BR2..I finished the cam gears and cam plates..They have been case hardened and look blotchy..I think all the oil passages have been reworked and associated parts also reworked. I need to put studs at various places and I think that is it for this phase..I think it may be time to make the lifters..


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## joerom (Jan 29, 2019)

I was just down in the basement working on this, and finally realized that the other part built BR2 that I have is not going to get done..I am getting older and I still have a lot of projects to do, so I think it is time to sell the other..I do want to finish this one and will keep posting here until it is done, but doing 2 of them is a pipe dream so the other to go...…..


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## Cessnadriver (Jan 30, 2019)

Hi I would be curious to know what you would sell the unfinished projects for?


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## bobden72 (Jan 30, 2019)

joerom said:


> I was just down in the basement working on this, and finally realized that the other part built BR2 that I have is not going to get done..I am getting older and I still have a lot of projects to do, so I think it is time to sell the other..I do want to finish this one and will keep posting here until it is done, but doing 2 of them is a pipe dream so the other to go...…..


Me too.


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## joerom (Jan 30, 2019)

I may have spoken too soon...……..


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## joerom (Feb 5, 2019)

I have decided to put up for sale the extra part built BR2 that I have for sale in the sale section here.....I know I will never finish the other one I have being that I turn 74 this year, and am getting too slow with too many projects...Reality has a way of stepping in......…….


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## Les99 (Feb 7, 2019)

joerom said:


> I have decided to put up for sale the extra part built BR2 that I have for sale in the sale section here.....I know I will never finish the other one I have being that I turn 74 this year, and am getting too slow with too many projects...Reality has a way of stepping in......…….



Hi Joerom,
Just out of interest, how much are you asking for the second Bentley?
Cheers,
Les


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## joerom (Feb 7, 2019)

Hello,
  Please go down to the
*Buy / Sell / Trade*
  section here, and all the info is there...…….
                                Joe


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## joerom (Feb 10, 2019)

When I took on this project, I thought I may have some problems along the way..I wanted to make the tappets, but could not figure how they were installed, being the eccentric shaft for the cam gears was already made and assembled with the ball bearing installed..I fooled with it for a while and just could not see how it was done, because the ball bearing on the eccentric shaft was mounted with a circular plate that was held down with screws, that could not be accessed when the tappets were installed..When I was downstairs fooling with it today trying to make sense of it, I discovered that the eccentric shaft was held on by a thin collar in the back, that I thought was just the shaft that was pressed on..It was done so well, that I just did not see this when trying to figure it out..So now I see how it is done and it is a simple matter to make the tappets and install them, and lastly install the eccentric shaft with the nut..I had made a dummy tappet to see how this all works, and it does..I just have to make the tappets now and I can proceed with the project..So, actually there never was a problem, other than me!


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## 58tux (Feb 12, 2019)

[see below]


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## 58tux (Feb 12, 2019)

Math of the Bentley BR2 cam.  The outer cam rings attached to the crankcase have 18 teeth.  The cams have 16 teeth,  For each turn of the cam rings the internal cam will make 1 1/8 turns.  Being this is a four cycle engine for all cylinders to fire the engine must make two revolutions.  So when the engine makes two turns the cams will make 2 1/4 turns ( 2 X 1 1/8).  There are four lobes on each cam, so 2 1/4 X 4 = 9.

Here is an animation of the cams drawn in Fusion 360 (click on image below):


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## joerom (Feb 17, 2019)

I started work on the tappets..I decided to make the stems from ground rod and then silver solder the bottom to it..The stems needed a concave depression in one end to accept the  ball end on the pushrod...I did not have a ball end mill that size so I ground one up from a drill bit..I first center drilled the end in the lathe, and then followed with my reground ball mill..It worked well..Then I needed to make the lower portion which will contact the cam, and drilled it for the stem..It will need to be ground to size  and shaped...That will be silver soldered on the end, and the other end cross drilled for the thimble that needs to be made yet.....


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## joerom (Mar 20, 2019)

I am writing to let everyone know that I have not given up on this engine..I am still very much interested in finishing it..It is just that I got involved in converting a mill to CNC to use down the line, and that is where I am right now..The conversion progress is posted on this site, and I hope to soo be finished, at which point I will get right back to working on the BR2, and the Gipsy Major...…………….


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## joerom (Mar 23, 2019)

I have gone as far as I can go with the CNC conversion until I get some better weather to paint the cabinet, so I am back on the BR2..I have made the thimbles for the valve lifters..These will need to be swaged to retain the ball end in the lifter and also cross drilled for attaching to the end of the lifter..I am getting closer to being able to assemble the crankcase into an assembly that looks like a BR2...This is still a very impressive engine to me and look forward to the day I can actually spin it for the first time...………


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## byawor (Dec 15, 2021)

I remebered this post and finally found it. It answers my problem with the cams I think. Thanks for posting\Bob


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