Chuff rate

Your assumption is correct. The STACK is the point of steam exhaust on almost all steam locomotives.

Dan Mitchell ==========

"KTØT" wrote:

At least SOME of the Soundtrax units CAN be cam-synchronized. I've seen, and heard, it done with great success.

Dan Mitchell ==========

SleuthRaptorman wrote:

Thanks Dan! Bob

Ah, dude, the exhaust stack is the same one for all 4 exhaust strokes. The real reason is that the valve gear isn't adjusted perfectly. When the valve gear is at the max. opening (in the corner, to speak) the amount of time that the valves are open is maximum and the amount is also maximum. As the valve gear goes toward the company notch (just barely off of the center position of the Johnson Bar), the amount that the valves in the cylinders open is a lot less, making for errors in setting, or the actual machining of the valves, more critical and thus one or more cylinder valve openings will be either larger or smaller than the others. Thus, the sounds become uneven in such cases.

-- Bob May Losing weight is easy! If you ever want to lose weight, eat and drink less. Works every time it is tried!

All I can say is next time to hear a kettle in action, listen. Listen closely.

Physics and engineering are one thing, but steam locos don't know squat about either.

It's like the old saw about bees being aerodynamically unable to fly, but they do anyway because bees don't know anything about aerodynamics.

-- Cheers Roger T.

Home of the Great Eastern Railway

Roger, Roger, Roger ...

The bees knew all they had to know. The scientists had to do the learning. *8->

Paul

The work of people like L.D.Porta, David Wardale and Roger Waller was/is largely focussed on improving overall efficiency and performance by improving the front end.

Sadly, no...

"Paul Newhouse"

LOL, how true.

-- Cheers Roger T.

Home of the Great Eastern Railway

This is borne out by comparing the exhaust sounds of a poppet valve steamer to a conventional slide or piston valve engine. The poppet valve events are more precise and square, so the exhaust lacks any noticeable beat.

Folks, Have any of these electronic exhaust sound dingii ever been applied to a Garratt model loco.? Garratts are well known for the exhaust beats from their two engines going into and out of synchronisation as they roll along. That'd be a bit of a challenge for the sound systems! Also, has anyone done it for three and four cylinder rigid frame engines? Regards, Bill.

Broadway Limited has done this on the N&W Class A and the new PRR T-1. most impressive.

John Glaab Peach Creek Shops

For a Garratt I would be tempted to put two sound units each synchronised to one power unit. The synchronisation would have to be done properly - a suitable commutator or cam switch on one of the driving axles.

For a three cyl>

snip