Author Topic: Lane and Bodley 400hp Corliss  (Read 60890 times)

Offline vcutajar

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Re: Lane and Bodley 400hp Corliss
« Reply #345 on: February 16, 2020, 08:24:28 PM »
Love the movement of the valve gear. :praise2: :praise2:

Vince

Offline Ramon Wilson

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Re: Lane and Bodley 400hp Corliss
« Reply #346 on: February 16, 2020, 08:53:14 PM »
Lovely work Simon  :ThumbsUp: :ThumbsUp:

Watched it more than several times - the left hand side seems to vary in lift and trip whereas the right seems to be quite uniform in action - surely you can't be that far off?

Very inspirational BTW  :) :)

Tug
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Online sco

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Re: Lane and Bodley 400hp Corliss
« Reply #347 on: February 16, 2020, 10:13:45 PM »
Thanks guys. 

Ramon I think what is happening with the LHS is the latch is releasing but the block sometimes gets stuck on the slider rod and is only released when the wrist plate reverses direction which then gives the variation in lift.  One of the mods I've made from the plans is to add a weight to the end of the damper rod (hidden under the base board) rather than having springs.  I did this because I found the spring preload was too great and made the latch too difficult to release which made the governor lever action very sticky, but the downside of this is there is not so much force to push the block along to snap the valve closed.  So I'm going to work on freeing up the sliding block - there's probably either a slight alignment issue with the wrist plate or maybe the rod surface finish just needs to be improved.

Simon.
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Offline deltatango

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Re: Lane and Bodley 400hp Corliss
« Reply #348 on: February 16, 2020, 10:19:57 PM »
That's impressive Simon, you really can't be very far away from having this working. As Tug said, it's inspirational for those of us who hope to get something like this working.
What are the diameters of the various rods in the linkage? On the Throp/Southworth model the rods look a bit heavy as drawn and I was looking at reducing them - but at smaller sizes they start to look too skinny to work well.

David
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Online sco

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Re: Lane and Bodley 400hp Corliss
« Reply #349 on: February 16, 2020, 10:31:02 PM »
Thanks David.  I have deviated a bit in the diameters of the linkage rods - partly to get closer to the look of the real engine but also because for the turnbuckles I only wanted to buy one size of lefthand thread tap and die so I think the rods are mostly 3mm and 4mm diameter.  I would choose a diameter that looks right and go from there.

Simon.
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Offline Ramon Wilson

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Re: Lane and Bodley 400hp Corliss
« Reply #350 on: February 17, 2020, 08:26:48 AM »
Morning Simon,

Just had another several views trying to discern whats happenning on that left hand side. Obviously foccussed on the trip gear itself at first I suddenly noticed that it appears that the gear arm itself has a slight movement in it as if it's not been tightened fully to the cylinder - it's particularly noticeable at the start of the clip. The right side arm is very firm in comparison so possibly the irregularity of latching on the left is being caused by this slight wringing.

Interesting point on spring pressure having too much effect - wonder if compressing soft rubber would be worth a try.

Like David I'm thinking of reducing rod size but it's the small thread sizes involved if so that will make for weak rods - tougher steel required maybe?

Keep at it Simon - great work

Tug


PS - Should have said - much easier to see this movement on 'full screen'
« Last Edit: February 17, 2020, 09:06:21 AM by Ramon »
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Offline deltatango

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Re: Lane and Bodley 400hp Corliss
« Reply #351 on: February 17, 2020, 09:52:47 AM »
Hummm, 2.4 mm stainless TIG welding rods take a 7BA thread quite well - just tried it. Now "all" I need are the mechanical properties of said rods and some idea of the forces involved. Might have to wait for a long while before I can measure those...

David
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Online sco

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Re: Lane and Bodley 400hp Corliss
« Reply #352 on: February 17, 2020, 10:20:24 AM »
Ramon,

Nothing is fixed yet - partly to identify binding issues, but you are right there's something going on with the left linkage that needs investigation.

Possibly I'm being nieve but I'm not sure where the big forces might come from - the eccentric to wrist plate rod is a large diameter because it is quite long and has to drive 4 linkages but in all the other rods I think the forces should be small so can't see where the problem would come from in using a smaller diameter rod.

Simon.
Ars longa, vita brevis.

Offline Ramon Wilson

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Re: Lane and Bodley 400hp Corliss
« Reply #353 on: February 17, 2020, 11:31:54 AM »
When you say 'nothing is fixed yet' Simon are you refering to the valve bonnets that locate to the cylinder? That's where I'm thinking you may find the reason for the left hand gear variation of engagement

As said when looking at it at fullscreen the left hand bonnet has a definite movement away from the valve gear as the claw engages whereas the right hand one is quite solid. Could it be that that movement is giving the variation in the claw engagement?

I wasn't referring to you reducing the size of the rods on your engine but those, as with David's thinking, on the Throp engine linkage.

Regards - Tug
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Online sco

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Re: Lane and Bodley 400hp Corliss
« Reply #354 on: February 17, 2020, 12:47:10 PM »
Ramon,

The bonnets are bolted to the cylinder block but there is a bushing inside the bonnet that locates the valve stem - that's not Loctite'd in yet nor is the arm locked to the valve stem.  But I think that movement that you've spotted is an indication of binding rather than free play - hopefully will get some time to investigate further this evening.

Simon.
Ars longa, vita brevis.

Offline Ramon Wilson

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Re: Lane and Bodley 400hp Corliss
« Reply #355 on: February 17, 2020, 01:00:28 PM »
Hi Simon,

I just ran this through a few more times at full screen. It's hard to tell if binding is the issue but if you focus at the small boss at the end of the valve arm you can see the sideways movement quite clearly. For the most part it moves in two distinct movements to left and up of the screen then for some reason seems to skip that movement and moves in one continous move. Having had this third look I can see the bonnet flange is motionless but theres a distinct sideways movement in that shaft/bearing as the valve moves

Be you can't wait to get home to find out eh :)

Spoke with Chris this morning - he's just finished another half size gem  :D

Regards - Tug
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(a very apt phrase - thanks to a well meaning MEM friend)

Offline Dennis

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Re: Lane and Bodley 400hp Corliss
« Reply #356 on: February 21, 2020, 06:44:58 PM »
Hi Simon,

You have done an outstanding job with the valves and linkage on this model.  The best I have seen.  I really like to see the trip mechanism work which is not common at this scale.  It is a credit to precision and workmanship in your model.

I think the smaller diameter linkage rods are much more accurate to the original engine.  The forces on the rods are small so strength should not be a problem with the smaller diameters.  John and I went a size larger on the rods than I would have liked because they would be easier for some model engineers.

Great work Simon, thanks for building this engine.

Dennis

Online sco

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Re: Lane and Bodley 400hp Corliss
« Reply #357 on: February 21, 2020, 08:37:11 PM »
Thanks Dennis for your kind words but it's a testament to your design skills that the trip mechanism works at all!

Last night I got the valve gear back together after polishing the slider rods and Loctiting the bushes in and it was working much better with consistent and equal trips left to right.  I started to use the crank to rotate the flywheel so I could get some speed up and was amazed to see the governor working properly to reduce the amount of valve opening and even stop them opening at all.  I was just thinking about setting up the camera for another video when the governor abruptly stopped spinning and it was clear it had seized solid, luckily I think without damage.  At the moment it's in quite a lot of bits whilst I fix what's gone wrong but hopefully it won't take long to sort.

Simon.
Ars longa, vita brevis.

Offline maury

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Re: Lane and Bodley 400hp Corliss
« Reply #358 on: February 21, 2020, 10:39:32 PM »
Simon, I've been tuning now and then. I like the work you are doing, very nice machining.

I was wondering how you made the brass ball ends in the linkage, and put such a nice finish on them? I need to make a bunch of similar parts for the Dickkson catwalk rail. Wonder if you could show how you did it. I was thinking about buying balls, drilling them, and soldering them to a post, but yours look so much better.

maury
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Offline Ramon Wilson

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Re: Lane and Bodley 400hp Corliss
« Reply #359 on: February 22, 2020, 08:23:39 AM »
Good to hear you solved the issue Simon, hope the governor will soon be back in good order and running again - looking forwards to seeing it run  :ThumbsUp: :ThumbsUp:

Tug
"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

 

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