Williams (Samhongsa) Brass USRA Mikado?

Another question.

Look at this photo of Q3 355, there's a pipe behind the smoke stack.  Is that the exhaust for the booster engine:

Here's a shot of Q3 352 with the pipe in front of the smoke stack:

Strange thing is, some of them don't have this pipe, like Q3 416:

Looking at this photo I see steam coming out from where the booster engine is on the trailing truck.  Some of them must not have had the pipe installed at all, if that's what it is.

So far I've found photos of 43 of the 117 Q3 Mikes Seaboard owned.

DONE!!! (almost)

Here's a photo of my Williams/Samhongsa USRA 2-8-2 conversion into a Seaboard Air Line Q3 Mikado:

Here's what the Williams engine looked like new:

A shot of that ugly front end:

QUESTION---Anybody know the drive wheel diameter of a MTH USRA 2-8-2?

I used a sound file from one of them but it doesn't appear to be in sync.  The Williams wheels are 1.3265" (a bit over 1-5/16") in diameter.  It could also be the tach tape I used.  Everything else seems to work fine.

I still have to do a bit of work, headlight lens, headlight number boards (lenses and lettering), re-attach the stirrups on the rear of the tender, and touch up some paint.

A lot of new brass hardware went onto this engine: domes, longer air reservoirs, bell, new front end with headlight, marker lights, air pumps, and piping.  Also a Delta trailing truck with Franklin booster engine and of course the Vanderbilt tender and Kadee couplers front and back.  Topped off with PS2 sounds/control it cruises around the layout pretty well.

Answer: it is the gear ratio that gets you.  Driver diameter should have nothing to do with it - a revolution is a revolution, no matter how big the wheel.

Count how many rotations of the drive shaft equals one revolution of the driver on both engines.  Then a little algebra should tell you how many stripes to paint on the tape.  I did it when I went to NWSL gears on a MTH Hudson, and it worked perfectly - white paint over every third black stripe.

So what you are saying is you do not know the gear ratio of the MTH model you got the flywheel from?

All you really need to know is that a two cylinder steam locomotive has four equally spaced chuffs per revolution.  Turn the new setup on, count the chuffs, then do some math to see how many black stripes you need to add or remove to make it four.  If you have eight chuffs, then use Snopake to get rid of half the black stripes.

So what you are saying is you do not know the gear ratio of the MTH model you got the flywheel from?

Not exactly.  The Williams engine already had the flywheel on it, I simply added a tach tape after building the diameter of the flywheel up using double-sided tape to 27.5mm (had to do this to close the gap between flywheel and tach reader mount).

With DCS I can select the number of chuffs per revolution.  I have 4 selected, but the drivers seem to be turning a bit out of sync with the sound.

I did a timing and the engine travels approx 1/3 mile (length of my small layout mainline) in 51 seconds, with the handheld speed set to 20smph.  It should be closer to 60 seconds, so it's moving faster than 20smph if this is any indicator (and not sure if it's pertinent).

At slow speed, less than 6 smph, the engine stutters a bit, above that there's no stuttering.  I suspect that's got something to do with the tach tape not matching up to what's there physically.

I'll do as you suggest to see if it's more or less a complete revolution.