[modeleng] Re: Mouland's Valve Gear

I had another long session at this last night!

You wouldn't think that setting up a simple system was so complicated!!!

I chose to do the LHS valve gear first.   This was primarily for the reason 
that the reversing lever was physically attached to the crank axle (vial 
various linkages) and I was certain that there could be no "slipping" or bent 
linkages.

I set the piston at Top Dead Centre, then set the crank axle to give me the 
port just about to open.  I then moved it to Bottom Dead Centre and checked the 
position.  If incorrect I moved the slide valve position.  Back to TDC, move 
the crank etc. etc.

Eventually I reached a point where the opening seemed similar between TDC and 
BDC and also between full forward and full reverse.

Now the decision time.  The crank axle was held on the crank pin by a slot cut 
in the rear and tightened  by a nut and bolt.  This had a tendency to slip 
round (thus creating the problem!)  The settings were unproved, but if I didn't 
pin the crank axle, the moment I tried it, it would be likely to slip and I 
would be back to square one!  So, pin and be damned.

I then set up the other side by the same technique.

When satisfied, steam covers replaced and held down temporarily with 4 bolts.

Compressed air applied and she ran as sweet as a nut (in forward and reverse).

All nuts were tightened, split pins bent and steam cover bolts replaced and 
tightened down.

So, this was about 2.5 hours of messing around with the two settings (on each 
side) eventually "spiralling in" to the best match.  I have no drawing for 
Mouland, so it was a rather empirical approach!  Do the members of the list 
have any alternative methods for doing this, or is this "hit and miss" approach 
the only option?

Cheers

Peter

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Peter Sheppard BSc (Hons) CEng FIEE FIRSE FSaRS
Principal Consultant
Lloyd's Register Rail Limited
5th Floor, 37-39 Corn Street
Bristol BS1 1HT

T: 0117 929 4443
F: 0117 929 4554
M: 07760 167 617
E: peter.sheppard@xxxxxxxxxx
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