Compound Condensing Engine

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At last - metal has been cut for the crankshaft! :big:

Two hours rough turning, leaving 1mm all over, and a BIG pile of big blue swarf - huge fun!
I've modified the existing plans slightly, in that I'll be making the eccentrics separately, so that I can geet the whole hardening/tempering/grinding process done - the profile of the eccentrics would I think have prevented the from being ground if it had been as one piece.

Off to the mill tomorrow lunchtime to start knocking a flat on to each side of it ;D

Crank - 12-12-11.JPG
 
Entirely unrelated, but here's a quick rendering of the Edwards Radial Engine, that I modelled a few months ago. I've got a billet of ally for the crankcase under my desk, but steam first this time ::)

Assem1.JPG
 
Sorry for the delay in posting, but I keep forgetting to take my camera down to the machine shop, so here's a quick catch up on the progress...



Crank 02.JPG


Mains And Big Ends.JPG


Valve Chamber 01.JPG


Valve Chamber 02.JPG
 
And the rest ;D

So the crank is now semi finished to within 0.3mm, and ready for big-end machining (but my mate is building a 1/4 scale Merlin, so we're taking turns on the lathe... :( )
The big end, and outer main bearings have been soft soldered together, and are in the roughing stages of machining. I'll finish these once the crank and bed plate are done though. I did find an interesting thing out though - I know the traditional method of bearing making is to solder the two halves together, but just out of interest, this time I tried bonding the halves of one big end bearing with Loctite 326, and it worked out nicely. So, if you haven't got soldering facilties, it might be a useful technique.
And for the last bit for now, I managed to get the circulating pump valve chamber done on the CNC today, so a nice little piece done :)

Valve Chamber 03.JPG


Valve Chamber 04 Done.JPG
 
Nice work Dave! I don't think I've seen a compound engine with a 180 degree crank before - will keep watching with interest. Hope your hand is back to normal. John
 
Glad you like it!
I think there was an issue about ease of starting with 180 cranks, but to be honest I didn't want to lose the original plans for this engine. If it needs modifying, then perhaps a cut & shut or remake could be in order. I do get the odd urge for a timber steam canoe to drop this in, so starting & easy reversing may well be an issue to save embarrasment around the local Tupperware toys ;)
And thanks, the hand is all good and useful - it'll never win a beauty contest, but I'd rather have it playing with a machine ;D
 
Yes my 1.5 x 3.0 x 2.5 pushes my 25 foot boat along nicely!
Nice looking parts and tip on the loctite Dave!

Dave
 
Hi,

I've made a few more parts for the engine, including flywheel, and some other odds, but i do have to admit that i've been side-tracked by some entablature engine plans that Pete sent me, so this one is being made first...
I'll start a new post on the entablature soon, but I'll definitely be back on this one later :)

Cheers
Dave

Assy - 01.JPG


IMG_0329.JPG
 
I did the entire project on AutoCAD drawings but i did just the two cylinder the covers and the crank shaft...I abandoned it in favour of The FS 835....
Best regards
 
Well, it's been far too long since I've posted on this build, partly with my entablature engine build, but there's been some very interesting work going on it the background.

Following on from chatting to Pete about this build, and becoming good mates in the process, he put me in touch with Dennis Howe of Historic Models and Reproductions (http://historicmodelsandreproductions.com/) and we've come up with a plan to develop and release both the plans and a casting kit for the engine. Over the last year, Dennis has finished his CNC router, and has been making some excellent progress on what promise to be beautiful castings. The first of these, the bedplate, is currently at the foundry and we hope to hear something from them this week.

Castings won't be for sale until we've proven the design 100%, but Dennis is quite happy to reserve sets if anyone is interested.

One thing I would just like to say is that it's been a great pleasure to meet like minded people through this forum, and work together in bringing what promises to be a stunning model back to life.

cylinder cope roughing.jpg


cylinder cope finished.jpg


condensing marine engine patterns.jpg
 
I'm really glad Dave and I can now finally talk about this. We've been keeping this quiet for it seems a very long time.

But maybe a bit of backround about this new/old engine that without everything happening just as it did, this Marine Engine as a casting set wouldn't be available to anyone. Or at least very soon we hope it will be available.The internet gets a great deal of bad press, and a lot of it is I guess well justified. But it can also work very, very well for something just like this engine. But I do want to make it 100% clear, neither Dave or myself have any commercial interest at all in this engine.

Due to a casting supplier in the U.K. that ripped me off for a set of castings for the M.E. Beam, I ended up hearing of another person in the San Francisco bay area who was also having major issues with the same supplier. He and I started emailing back and forth, and I have I think learned a very large amount from him about stationary and marine steam. He also got me more than interested in those early marine steam engines, and sent me a link to Historic Models and Reproductions since he had just bought a set of castings from Dennis, and he also knew I was interested in the Corliss valved engines. Shortly after that I then purchased a set of L&B Corliss castings from Dennis and was more than very impressed with the overall casting quality, drawings, and even how Dennis handled my order. Since that time Dennis and I have remained in touch, and I'd like to think we've become good friends who just haven't met yet. At around that time I ran across a link for Elliot Bay, and spotted there small pictures of a version of this Compound that might have been done from the old Clarkson? produced castings in the U.K. Dave has used those pictures of that engine in his first post on this thread as bait :) I then tried to order a set of castings from Elliot Bay. They weren't available at that time, and I'm assuming that's still the case since they haven't let me know there now available despite numerous past emails. Also around the same time I bought a pretty complete collection of Model Engineer magazines from 1898-1960's, and then ran across the write up for this compound that was done in those magazines that Dave has mentioned. That just made me want a set of those now unobtainable castings even more.

I'd guess it was also right around the same time I was trying to get castings from Elliot Bay that Dave was also doing the exact same thing, and getting the same results as myself. The very large difference between He and I? He's one hell of an excellent commercial designer, machinist, and more than very experienced with the commercial quality Solidworks CAD program. And you can then add to that a deep interest and appreciation of both Stationary and Marine steam. All of that togeather has to be more than a very rare combination today. So after I spotted his very first drawings for the compound in this thread, I then pmed him, and we began emailing back and forth. I think we've now both become very good friends who again just haven't met yet. But I never forgot about, and I still kept wanting a set of those castings. So due to the quality of my L&B Corliss castings, I again thought of Dennis and his company. By almost random chance, I decided to scan a drawing of this engine from one of those old Model Engineer magazines, or I emailed him the Elliot Bay pictures asking him to consider it as a casting kit for his company. I'm a little unsure now exactly what I did email him for drawings or pictures.

But funny enough he'd seen a couple sets of castings in the past that were obtained from the U.K. many many years ago for the original version of this compound engine. But those original casting kits are now no longer available. But luckily he did know of this engine, and had also been at that time seriously thinking of adding some type of marine engine to his company's lineup of casting kits. We then started to email back and forth quite a bit until he was just about committed to doing this engine, but he was also thinking of and a bit concerned about all the work it would take just to do the drawings from scratch. I then thought of Dave and all the work he'd already done on this engine, and this thread. I was pretty sure the very fine drawings Dave had done up to that point should work for Dennis's needs. So it wasn't a real giant mental leap to add two and two, and I then sent the both of them each others email address. At that time they both agreed to work on this engine as a joint effort. So from that point on all the work has now been done by both Dave and Dennis. Although I have gotten to see some of the work that's been done. But from the pictures and drawings I've been sent so far, Dave has produced an excellent set of CAD drawings, and Dennis has used those and what I think is a very accurate 3 axis CNC router system He's built that's now working on the very first patterns for this engine, and as that CNC routers very first project. I think the great pattern pictures Dennis has sent us and that Dave's added here should more than speak really well for themselves about what kind of castings they should produce.

But without all 4 people in this story who still haven't ever met each other yet? And who are scattered up to 8,000 miles apart, and all the other little fractions of life's almost random bits of luck both good and bad aligning themselves just right. Then this engine would probably still be just a set of dusty drawings in one of those very old magazines instead of a soon to be commercial casting kit. But one thing this engine will have that's quite rare on any model marine engine I know of today is the proper design and casting for the condenser housing. The internal tubing will of course be up to the builder. At least we hope it will have that housing, the casting is from my information pretty complicated and thin walled. So it could be extremely hard to do in this size. But if anyone can pull it off, I have faith Dennis can. The pattern and cores for this casting should be done sometime this week. I'm not quite sure of the first trial casting date for those yet.

And according to Dennis, it's a bit too soon to come up with what the exact price will be for the castings and drawings. As soon as one of us does know that, then we'll certainly post it on this thread. But for at least the interested Marine Engine builders here, I think your about to soon have something that's maybe a little bit unusual, and it all pretty much started just about right from this thread. And unlike a huge number of casting kits avalible today that can require a larger 9" plus swing on a lathe for the flywheel, or maybe a larger mill due to an engines bedplate size. This one should be capable of being machined on some of the more basic and less costly 7" swing lathes and X2 type mills if the builder is willing to do a good job tramming and aligning there machine tools.

Edit: After a re-read, it seems both Dave and I have forgotten to mention that these castings are being poured and cast in a proper commercial quality foundry

Pete
 
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Here's the pattern and cores for the engine, and I think they bode very well for some quality castings. Personally I'm aiming for a mixture of manual and CNC machining here, but we'll document the build thoroughly and make sure there's no CNC only work involved if at all possible.

There's one other thing that does keep running through my head, and thats adding a barring engine to this too, and possibly, rather than just a plain base, building a scale section of the hull beams and engine room decking to mount the model on ;)

Roll on making some swarf :cool:

DSC04819.jpg


DSC04821.jpg


DSC04824.jpg
 
Well here we go - the first casting for the engine, and Dennis has done a brilliant job! Thm:

The foundry have poured a pair of bedplates as a test run on the patterns, and while we haven't yet checked dimensions to make sure the shrink was correct, there's enough stock to make the part work even if it is out a little. And as for surface finish? Lovely!

I'm not sure how long shipping for the prototype to the UK will be, but there'll be some swarf in the very near future..woohoo1

CM_Bedplate_1.jpg


CM_Bedplate_2.jpg


CM_Bedplate_3.jpg


CM_Bedplate_4.jpg


CM_Bedplate_5.jpg
 
Interesting story guys,

And what promises to be a beautiful engine.

Thanks for sharing,
Dave
 
Hi Dave,

Glad you like it - I think it should be fun.

With seeing what you get up to with your Pacific project, it'll be fun to work with castings again :D

Dave
 
Somewhat OT: do you think that patterns machined from machineable wax would work (vs. wood). I recently bought a large quantity of wax at an auction quite cheaply.
 
Dennis would be the best person to ask on this one, but I can offer a little from personal experience. A couple of yeasr ago we had a 3D printer installed at work, and I spent some time chatting with the engineer about whether wax patterns could be printed with it (with a slightly ulterior motive ;) . Apparently there is a wax it can use for this process, but care has to be taken on the type of wax to ensure that it flows cleanly from the mould. If you want to PM me your email address I can send you the PDF on the process that he gave me. Or, let me know on dclark at thorlabs dot com
 
Kvom,
I can only repeat what I've picked up about the process your talking about. Probably, but I'm not 100% sure your wax would work. Exactly how well? The castings might not be as good as using the proper wax would allow. But yours has been formulated as a proper machinable wax, and not something that's been designed as a mold wax. The wax pattern needs to be dipped many times in an investment slurry and then allowed to air dry between coats. That builds up the thickness of the investment (it's much like but isn't a very thin wall plaster) so it can support the metal as the cast is made. Once the investment thickness is built up and air dried, it goes into a programable oven that both slowly ramps up the temperatures to fully dry the water from the investment mold, and then it ramps up to melt the wax out, and then high enough to burn out any wax that's left, and even high enough to burn off any carbon left from the burning wax.

I'm guessing, but as I said, I just don't know for sure if your machinable wax has the exact properties that are needed for an investment wax. Any investment casting company should be able to tell you yes or no though.

Pete
 
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