Black 5 smoke unit

[DarkRedCape]

I just received an email from Hattons about an upcoming Black 5 model. I have the SS version on pre-order, but the one in the email is considerably cheaper.

In the details it lists, provision for a smoke unit. So this is obviously the SS version without the smoke unit, but this wording has me curious. Does this simply mean you can add your own smoke unit, or that Hornby will sell the smoke unit separately? I can’t personally see Hornby selling the unit as a stand alone product.

So I’m thinking this is just the SS version with no smoke unit, and there is a space inside for another brands smoke unit, or a custom one.

Here is the link, details are in the mechanical section: https://www.hattons.co.uk/directory/versiondetails/5461/hornby_oo_4_6_0_class_5mt_black_5_lms

[Going Spare]

The loco you have on pre-order is R30225SS with a smoke unit fitted.

Hornby are/were also offering R30226 and R30227 as non-fitted models (the search engine no longer finds R30226) at a price, with 10% off, giving roughly the figure you are quoting.

The basic loco body & chassis are no doubt the same for both smoke unit and non-smoke unit versions, Hornby themselves opting to fit the unit in R30225SS.

Whether Hornby ever offer the smoke unit by itself remains to be seen.

[ColinB]

Now if they did, I think that could be a definite money spinner but it depends on what is required to fit it.

[atom3624]

It also depends what it will fit.

If it's a unit which can be retro-fitted into A4's, Coronations, BoB's, etc., it could make a small fortune ...

Al.

[SteveM6]

Looking at the specifications of the SS Black 5, retro fitting to other locos seems to involve a lot of wishful thinking. Generator, reservoir tank, 21 pin decoder and the extra wiring is going to be a challenge in a loco not designed for it from the outset.

[Simmo009]

Don't hold your breath, they have only recently released pictures of the EP, so 18 - 24 months at the earliest until you may see one to actually buy, with or without smoke unit fitted. Just being realistic, not complaining in any way.

[96RAF]

The ASU modules will be a bespoke fit for each loco type and unless Hornby policy changes there will not be any retro-kits for them.

This would not be the same as bunging a decoder into any gap. The loco will have to be moulded to suit the ASU module and as stated additional wiring plus the right decoder with the right profile as it only works with the 7000 series decoders.

Even TRS trains who has been doing it for a long time does not have universal or for loco type retro-kits, all locos are bespoke modified by return to works at great cost including a matching sound decoder.

[DarkRedCape]

The R3991ss Flying Scotsman is scheduled for release this autumn. It's release date has already been pushed back once, or maybe even twice, so it could possibly happen again.

If it does release this autumn however, we'll get some hands on experience with the unit and then probably gauge whether it's something that can be fitted to other locos. It's obviously not going to be a plug and play system, but modelers are very creative.

[atom3624]

It's a huge pity making something so 'bespoke'.

I suppose it means it should function well, and in keeping with the locomotive it relates to.

4 chuffs or 6 chuffs per revolution - this time they must get it right.

Would love to see it installed into a Lord Nelson - 8 / revolution!

Al.

[96RAF]

The function is the same in every loco. The decoder by way of CV settings tells the ASU when to chuff and for how long. Each associated profile will set the decoder up to do this.

The form and fit are the problem as each loco internal space model will be different therefore the ASU water tank shape and associated PCB interface with the decoder will be different.

What hasn’t been discussed yet is the proposed chuff synch unit that will be fired by a wheel driven interrupter. This will ensure chuffs are accurately synched during those speed steps that the eye can discern, thereafter it will revert to the standard coarser synch provided by the complex speed curve set up.

[atom3624]

I sincerely hope so.

Each time I saw a 'marvel' of a Sound locomotive, even in the series, you could hear my teeth grinding!

Something like that, and costing so much, even TTS 'el cheapo option' ones really should be a lot better - never seen one video of them remotely closely synched!

Often appears they're close at 20mph equivalent, but when at closer to 60+ it's like Thomas the Tank engine animated cartoons, with one to two chuffs per revolution - horrible!

Sorry for the rant, but it gets my goat.

Al.

[DarkRedCape]

Could the chuff sync be added to a HM7000 profile? If I had a 9F profile installed then the ASU would know how to sync the chuffs without the need for a wheel driven system as the app has the speed slider from 0-100, so it could determine the chuff sync from this. Is this something that’s possible?

[What About The Bee]

Hello DRC

You asked if the chuffs could be estimated from the velocity notch on your control unit.

That would provide a first order approximation. That is, you could calculate all the gears and motor revolutions, such that the chuff is played at a particular time relative to the frequency of wheel rotation and therefore command.

But therein is the first issue. A real steam engine exhausts steam at a particular orientation, not some random orientation of the slide valve. That information is not contained in the commanded velocity.

Another issue is that motor velocity is not a constant over time, nor perfectly proportional to command. It is an open loop motor, meaning no feedback as to position. No encoder. Therefore, when you apply the power to the motor, you will certainly be within a range but you will not be spot on. Thus the chuff will not occur at a specific wheel orientation, rather, it will be at a random orientation that drifts over time.

A simple feedback mechanism synchronizes the chuff to the wheel orientation. It could be as simple as a tiny rare earth magnet affixed to a driving axle. The sensor could be a hall effect sensor which detects the magnetic field. Each time the hall effect sensor detects a field, produce a chuff. You desire 6 chuffs per revolution, have 6 magnets. 8 chuffs? 8 magnets. 4 chuffs? 4 magnets. This self synchronizes and produces perfectly timed chuffs to drive wheel orientation.

I do recognize that the sound of a particular chuff is related to the velocity and therefore the chuff sound profile must be manipulated with respect to the chuff frequency. That's a knock on problem, once basic synchronization is solved.

Bee

[96RAF]

I suppose you would also like light engine and heavy consist chuffing to be selectable or applied automatically.

At present you have wheel slip associated with throttle demand. Too much throttle and the sound will slip wheels just like a real loco. The interaction parameters are adjustable by CV. This overdrive between throttle demand and road speed is used in the basic chuff synch system as is to select which chuff band to use.

The chuff methodology described by The Bee relies upon a constantly available chuff versus speed not chuff band ranging as is used now. Using the complex speed curve this ranging can be better matched to a particular loco, but this relies upon the complex speed curve becoming default rather than the basic 3-point curve generally used.

[Tony57]

Hii

Having watched the Hornby series on yesterday, until the sound files contain the Loco going at 20, 30, 40, 50, 60, 70, 100 mph will they sound right. The amount of steam used at the cylinders to start a train is totally different to the amount used when moving at speed. Having see real locos running and listening to them, the model sound fitted ones today are wrong sounding when moving at speed.

I prefer my old Triang Hornby Hall with its scrap box and Mainline Royal Scot with its battery hiss box, with these the noise from these change when going faster.

[atom3624]

I had a look at the latest video of the Pete Waterman model railway in Chester Cathedral - looks fantastic.

I noted there was a Sir William A Stanier (Princess Coronation, latest tooling) with a sound chip - totally out of synch., with between 2 and 2.5 beats per revolution - HORRIBLE!! (It should be 4 for a 4 cylinder.)

Al.

[DarkRedCape]

According to this article, the smoke output will be set by the HM7000 decoder and the chuff rate will be set by a sensor on the wheels. This article is for the P2 but I’m sure the system for all three SS locos will be the same. I’m really looking forward to see how well this all synchronises.

Article is here: https://uk.hornby.com/community/blog-and-news/news/prince-wales-new-generation-steam?xnpe_tifc=4FblOkPL4.U.x.UuOFVDhMpsafeWaeiWhFW9bf89VjQL4kpWhuo74DH8nkLvEkJLRfXcbdiArFxJ4.eNx.1ZOfnJ4I4uxFoT&utm_source=bloomreach&utm_campaign=Hornby%20-%20P2%20-%20week19%2023/24&utm_medium=email

[atom3624]

Good spot DRC: Another development of the steam system is the use of a sensor which accurately detects the wheel speed of the locomotive and perfectly syncs the sound and steam effects with the piston action of the locomotive.

Al.

[96RAF]

Good spot DRC: Another development of the steam system is the use of a sensor which accurately detects the wheel speed of the locomotive and perfectly syncs the sound and steam effects with the piston action of the locomotive.

Al.

 

 

There is quite a difference between piston synch and wheel synch. There is also the reverser cut off to consider and load at start and in cruise.

Initially all sound profiles will have the modified speed curve settings applied to give best coarse synch.

[atom3624]

After the not-too-convincing TTS efforts this should finally bring sound (and smoke) into the 21st century.

Al.

[atom3624]

After the not-too-convincing TTS efforts this should finally bring sound (and smoke) into the 21st century.

Al.

[What About The Bee]

In discussing "chuff", I think it important to revert to first principles. Hold the discussion of how to reproduce the sound. Understand first how the sound is produced and the variables that affect the prototype sound.

The following is a highly simplified drawing, used to illustrate my understanding of chuff.

In every event, one must consider that the pressure will attempt to reach equilibrium between vessels. Given enough time and flow, two connected vessels will achieve the same pressure. This is inescapable.

The boiler is at 120 psi. When the regulator valve is opened, steam will be allowed to flow. Yet the admission of steam to the cylinder is via the slide valve. Assume the slide valve opens and steam enters the cylinder. Steam in the cylinder may escape via the drain valve or up the chimney. It is the vent of steam to atmosphere that produces the chuff. The steam is at 120 psi. The atmosphere is at 14.7 psi. Therefore, the steam rushes to the "vessel" with the lower pressure, to find equilibrium. Chuff. 

Due to slide valve timing, exhaust must begin before steam admission. Therefore, steam admission sounds are masked by exhaust sounds.

The slide valve is directly coupled to the valve gear. This is mechanically synchronous with wheel rotation. The chuff and wheel orientation is mechanically fixed and bound by the valve gear. This is most visible to even the most casual of observers: synchronism.

The frequency of the venting of steam is therefore directly related. The duration of each vent event is inversely proportional to the velocity. The higher the velocity, the shorter in time the vent event. These two factors will alter the sound. High frequency, short chuffs will sound dramatically different from low frequency, long duration chuffs.

The engineman may alter the amount of steam admitted to the cylinder via the regulator. I think of the regulator as a constriction of flow, and thus the steam admission a rate flow problem. An analogous situation would be a sink with a faucet. The faucet valve permits a varying flow, from a dribble to a torrent. If the regulator is wide open, the steam pressure in the cylinder will reach equilibrium with that in the boiler.  If the regulator is barely open, the amount of steam admitted will not cause the pressure in the cylinder to reach equilibrium during admission event. The slide valve will close before equilibrium is reached.

Therefore, upon the vent event, the amount of steam exhausted will also be a function of steam admission. The pressure differential will cause amplitude variations to the chuff. More steam? Louder. Less steam? Softer.

The engineman may also open or close the drain valves, to prevent water hammer in the cylinders.* Thus, when steam is admitted to the cylinder, it is also directly vented to atmosphere and the chuff is dramatically reduced in amplitude.

The tone of each chuff will be a function of the chimney and exhaust vent aperture. The chimney will be the resonant chamber, the throat of the sound. The exhaust vent aperture are the vocal chords that excite the resonant chamber. Therefore, each locomotive class should have a different sound to other classes. Further, minor variations within class will be evident under spectral analysis.

To review:

1) the amplitude of the chuff is affected by steam pressure in the cylinder. This is a function of engineman regulator and drain valve settings.

2) the frequency of chuff and the duration of chuff are mechanically linked by the valve gear as it controls the slide valve.

3) this is perfectly synchronous with wheel rotation. It is mechanically linked.

4) the exact tone will be a function of locomotive class and build.

Respect the prototype. Match it, or expect enthusiasts to not like it.  

Bee

* Planet did not have drain valves, the warmed inside cylinders were theorized to vaporize the condensed water. Needless to say, that was an error corrected in later locomotives.

[atom3624]

All makes sense.

Al.

[96RAF]

Bee talks about synchronicity of the slide valve with the motion, but there is an extra factor, the reversing lever/screw, which alters the juxtaposition of the slide valve with respect to TDC of the piston within the cylinder to give a gearbox effect to the drive. At start the lever will be set to full forward, but once rattling along it is wound back nearer the mid gear position, affecting the chuff sound and timing. There will always be a matching number of chuffs to cylinders but the when and how loud is also important.

[atom3624]

All of this makes sense. There was a video a couple of years back, with 46115 Scots Guardsman, and everything was out of synch - a good overhaul of the cylinders, pistons, etc., I think was required, but it sounded ... terrible! Seemed to haul and run OK nevertheless.

Al.