# 2 blast pipes; 2 chuffers?



## Chris Scott (Jan 2, 2008)

Several Accucraft locomotives have two separate blast pipes one for each pair of cylinders. i.e., Bib Boy, Cab Forward, Allegheny, etc. 

Could they have 2 Summerland Chuffers ?


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## Chris B (Oct 18, 2009)

Hi Chris
Well I would have to look at the detail, but in theory it is possible. A number of Accucraft NGG16 Garratts have been fitted with two, but this has been done by separating the two exhausts as the wet steam from the rear power unit tended to drown a single chuffer. One I know has two chuffers in the drilled out stack and others have one in the stack and one in a resonator underneath. 

Two blast pipes (or more likely two crimped copper tubes) is a great start and I have recently designed resonators to cope much better with small and unusual stacks so I am always happy to give it a try. As always I need the stack dimensions and the exhaust details. 

Cheers
Chris (the Summerlands guy)


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## Chris Scott (Jan 2, 2008)

Chris:
The Cab Forward and BB have two superheaters and two blast pipes. 
Safe to say the Allegheny is the same. Cliff has it at Stavers' with weekend 
I think the T1 setup is probably the same, (maybe someone can confirm.)

There is no stack per se to either, save ~1/2" collar above the boiler shell - technically I suppose they would be their "stacks." 

Blast pipes are not crimped and stop just below the top of the "stack" 
There is no wedge cut in the blast pipes. 
The blast pipes have threaded fittings.

The smoke box is completely open from the front of the boiler to the "front door." The smoke box dimensions on each;
- The BB smoke box is ~5.25" Deep x ~2.15" Dia.; 

- The Cab Forward smoke box is ~2.75 Deep x ~2.75" Dia. 









Don't you think the chuffers will be very loud with all that open smoke box space acting as resonator, particularly since there will be two?


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## Chris B (Oct 18, 2009)

Now this is a challenge Chris!

The reason that the chuffer is so simple is that it relies on the stack tube to create resonance which deepens and amplifies the sound. The flue gasses also pick up the steam and so retain much of the steam plume. Normally, if the chuffer is below the stack, the sound is minimised - but I am wondering:
a) whether this would work OK with what is essentially a big chamber with a hole in the top.
or b) whether we could use a pair of tubes inside the stack to create resonators. A view of the top and dimensions of the stack holes would be good.

Also, when the door is closed, is there an opening in the bottom of the smokebox so that the burners can breathe if we restrict the stack at all?

Should we take this (potentially commercial) discussion off list - or are other folk interested?

Cheers
Chris


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## Kovacjr (Jan 2, 2008)

Chris I have a Bigboy here and think the GP10 might work. Also the T1 is NOT gas fired don't bother with it.


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## Accucraft UK (Sep 16, 2013)

....not to mention the UK models of A3 and A1... but with a Kylchap exhaust they don't really need a chuffer per se!

Graham.


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## steamtom1 (Jan 2, 2008)

Here is a video of my dual blast pipe loco. It almost doesn't even need a chuffer... 





 
Could be that the second set of four chuffs is 180 degrees out of phase with the first set, making the sound actually a double chuff.


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## Chris Scott (Jan 2, 2008)

steamtom1 said:


> Here is a video of my dual blast pipe loco. It almost doesn't even need a chuffer...
> 
> 
> Could be that the second set of four chuffs is 180 degrees out of phase with the first set, making the sound actually a double chuff.



Since the individual chuff chuff chuff diminishes with speed, if you double the number of chuffs won't the sound of individual chuffs go away at half the speed?

_Ok, it's academic but is how the mind sometimes works, or not. _


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## Kovacjr (Jan 2, 2008)

Tom your Duchess doesn't count! haha its got a real setup with nozzles and petticoat and a real drafting.


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## Dan Pantages (Jan 2, 2008)

Tom, Chris is talking about Accucraft engines, not Aster engines. None of my Aster engines need a chuffer.


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## Chris B (Oct 18, 2009)

Dan Pantages said:


> Tom, Chris is talking about Accucraft engines, not Aster engines. None of my Aster engines need a chuffer.


No indeed Dan - as Jay says, they have a proper set up and adding a chuffer to an Aster (other than the Kraus) would be a disaster!

There is an option to use just one chuffer to halve the beats.

Chris - send me a PM if you would like to take it further. In the meantime I will drool over the loco in Tom's video ;-)
Cheers
Chris


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## Chris Scott (Jan 2, 2008)

Chris,
PMs evidently not avail in the new MLS. I'll email you.


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## redbeard (Jan 2, 2008)

*PMs*

Hey Chris,
The issue with PMs is ONLY in the classified ads, (or possibly on the home page) the PMs in the forum work fine.

Larry


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## steamtom1 (Jan 2, 2008)

Chris,
Check your PM inbox.


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## roadranger (Jan 6, 2008)

Most Roundhouse engines have 2 steam exhaust pipes, one each cylinder, and Summerland engineers a Chuffer for the RH engines with 2 inlets. Maybe a Roundhouse Chuffer would work?


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## Joe Johnson (Jan 2, 2008)

Chris,

I'm in the middle of a Aster Kraus build. Why would it be different from the other Asters. Already have a Aster Shay. Just curious for now.


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## Chris B (Oct 18, 2009)

roadranger said:


> Most Roundhouse engines have 2 steam exhaust pipes, one each cylinder, and Summerland engineers a Chuffer for the RH engines with 2 inlets. Maybe a Roundhouse Chuffer would work?


That's interesting Jim - I had not thought of that! Of course, as you say, the RH locos have two cylinders with two exhausts giving four beats per revolution of the wheels. Driven slowly they give a nice, distinct chuff through a single chuffer. The Big Boy has four cylinders for the two exhausts and so eight beats per revolution. The chuffing may well get blurred at speed.....but it is food for thought.......

Cheers
Chris


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## Chris B (Oct 18, 2009)

Joe Johnson said:


> Chris,
> 
> I'm in the middle of a Aster Kraus build. Why would it be different from the other Asters. Already have a Aster Shay. Just curious for now.


Hi Joe
I am afraid I don't know about the Aster Shay, but I do know that the Kraus is internally gas fired and has a single, large exhaust. A Chuffer tube pushes down inside. Most Asters are internally spirit fired and use a blast pipe to draw the fire - a chuff pipe of any kind does the opposite by using the energy in the exhaust to create sound rather than a vacuum to draw the fire.
Cheers
Chris


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## BigRedOne (Dec 13, 2012)

Joe Johnson said:


> Chris,
> 
> I'm in the middle of a Aster Kraus build. Why would it be different from the other Asters. Already have a Aster Shay. Just curious for now.


Aster's Kraus is butane fired. Butane is a pressurized fuel.

Alcohol or coal locomotives need the velocity of escaping steam from the exhaust to pull air though the boiler flues and through the firebox.


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## Kovacjr (Jan 2, 2008)

The new Alisan Shay is also butane fired.


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## Joe Johnson (Jan 2, 2008)

Thanks for the explanation Chris, that told me what I needed to know. As Jason said - the Shay is also butane fired as are my other engines.


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## David Leech (Dec 9, 2008)

Dan Pantages said:


> Tom, Chris is talking about Accucraft engines, not Aster engines. None of my Aster engines need a chuffer.


Let's be honest here - NO engine NEEDS a chuffer.
There was one fitted to a loco at Stavers this last weekend, and it was so loud, that you could hear it from the other end on the track, and it did not sound real at all.
To my mind, a little chuff goes a long way, and a real loco did not chuff when throttled back and cruising, only when working.
All the best,
David Leech, Delta, Canada


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## Semper Vaporo (Jan 2, 2008)

If the engine is alcohol or coal (or wood) fired, you probably do NOT want a "Chuffer". Not that you would not like to hear a more pronounced chuff sound, but you NEED the draft induced by the exhaust going up the chimney and a "Chuffer" would interfere with creating that draft and ruin the proper operation of the fire.

The "Chuffer" often derives the sound by turning the flow of steam sideways to blow against the side of the chimney or into a resonator and that ruins the venture effect of the exhaust stand in the stack/petticoat and you get no draft over the fire.

You could get fire coming out the bottom of the firebox ("hunting for oxygen") instead of going through the flues, or the fire could go out for lack of oxygen, or fuel (alcohol) could even dribble out and set fire to the ties because there is not enough oxygen to get it burned before it drips from the wicks.

Gas fired engines usually do not need a draft because the fire is blown into the flue by the gas pressure and so can have the sound enhanced by a Chuffer with no loss to the efficiency of the flame.. AND a Chuffer can improve operations since it often traps water (condensed steam) and keeps it from dripping back into the fire area where it boils under a layer of oil that is also deposited from the exhaust, which causes that popping sound that disturbs so many people (and sometimes puts the fire out!).


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## Kovacjr (Jan 2, 2008)

David, what was that one loco? There are some that are very loud and many that are just a boost in sound. I'm sure you have heard the Aster C&S, that's loud!


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## steamtom1 (Jan 2, 2008)

Down @ DH you could hear the EBT out in the parking lot, and probably inside the DQ.


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## David Leech (Dec 9, 2008)

Kovacjr said:


> David, what was that one loco? There are some that are very loud and many that are just a boost in sound. I'm sure you have heard the Aster C&S, that's loud!


Jason,
I'm not sure as it was on the Seattle portable track and I didn't bother to go over, but it was big and black, so either a Fairymead or an Enima.
Cheers,
David


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## Nick Jr (Jan 2, 2008)

I had Chuffers on some of my loco's that I have removed, and I am hearing impaired. Noise volume doesn't always equate to real sound.


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## Chris Scott (Jan 2, 2008)

At the summer steamup, the last one in the smaller venue, I think it was either an Acc C-16 or C-21 that was really really loud. I suggested a volume control was needed. It was very frustrating. 

On the largest track even if the loco was at it's maximum distance of maybe 30' it was so loud I could not hear my loco's burner pop back or anything else. I gave up and gave away my time slot it was impossible to hear my loco to run it. There is just so much feedback from sounds you depend running a steamer that a lot of noise really gets in the way. 

I know this seems a strange comment since I started this thread but that's curiosity...so there you are. Like Einstein's thought experiment, he never built an elevator in space either. Maybe that was Disney's cartoon that had the elevator? Einstein's thought experiment involved a box. 

I'm sure there are more than a few who initially read this question and who's reaction immediately was why would anyone want to add a chuffer to a Big Boy or Cab Forward. As well as, "...where in the **** does he come up with these things?" Guilty! And by this time it's become, I have a reputation to maintain. ;-)) ;-))

I have to agree with David some small locos are good with a chuffer. But for other locos, particularly larger ones, natural chuff is enough. For others they like and want a chuffer for their locos, large or small.


(I did not know that this editor will automatically substitute asterisks for one of the child inappropriate words?)


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## Charles M (Jan 2, 2008)

While I like the sound of a chuffer on an engine , I want it to be running on ground level. When running on an elevated track the sound is too much, and it gives me a headache. A friend has a K36 fitted with a chuffer and we both agree it is too loud on the elevated track. I may have to take along earplugs in the future. 

Charles M SA #74


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## Kovacjr (Jan 2, 2008)

One must remember that the chuffers were also designed for the garden railroad not elevated indoor tracks. Originally people just wanted loud now there is a more fine tuned approach to the sound. If one is too loud we now have a cap that allows you to adjust the sound. If does require you to drill a hole but that's it. Also for some locos there is a MK II chuffer like the K36 and the C25 that were very loud do to the stack resonance. The K37 has one but is the newer larger chamber. Also the Fairymead has a similar design.


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## Chris B (Oct 18, 2009)

Jay makes a good point - Chuffers are designed for outside running and always to give the optimum sound for the particular loco. The trouble is that folks' view of 'optimum' differs! 

I confess that I enjoy the design challenge, but just about every one of the fifty or so designs (after the first three) was done as a result at a customer's request. The first three were for me because (and this is a personal thing) a silent steam loco just doesn't do it for me. 

As Jay has said, I have designed deeper sounding chuffers for a couple of locos, but this is always dependent on the size of the stack. I am also working on a Control that will allow the chuff to be adjusted very easily - from full volume down to a whisper for indoor running. It will be a retro fit on many (but not all) current chuffers. Maybe this would help....?

Cheers
Chris


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