What About The Bee
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And Stephenson's approved image of the carriage.
Note that this is a cut away image and you can see inside.
Note also the spokes, per another discussion
Bee
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Granted!
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Depictions by period artists, known good observers, show straight spoked wheels. Image after image, straight single spokes.
Stephenson approved a drawing of a third class (blue) carriage. Straight spokes.
The manufacturing problem is this. A cast wheel has three main components. The hub, the spokes and the wheel itself. When cast, the unequal mass of the spokes compared to the other components makes them cool more rapidly. This cooling causes shrinkage. Which sets up stress concentrations, cracking and breakage.
R. Stephenson is noted as early as 1815, working on this problem with Dodds. Dodds' nephew, who apprenticed there, later patented a wheel arrangement in which the spokes were tangent to the hub and at an angle to the wheel.
81F - this was a period of the grand railway experiment. Either choice is acceptable. Stephenson even patented a wheel that used tubes for spokes, the metal cast around them.
But if you want to match the imagery, straight spokes it is
Bee
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Hello John
As this is your first post, welcome aboard!
I was hoping that someone would be along to help you sooner.
The Hattons web pages state that the locomotive in R1119 is a West Country locomotive. Hornby have produced a few, R2219, R2315 and R2685 to show a few.
The service sheet associated with those West Country locomotives is HSS 249f. You will be able to access that right here
https://support.hornby.com/hc/en-gb/search?utf8=%E2%9C%93&query=R2315
Upon examination of that support sheet, the gear set is indicated as X8849 as a spare part.
Peters Spares used to have the 26 tooth version
https://www.petersspares.com/p/hornby-x8849l138-idler-gear-locked-set-china-built-locos-138mm but claims to now be out of stock. Its worth a telephone call, just to get information before you try other sources.
That's as far as I can go.
Bee
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Welcome back to another OO Planet update. Since the time of the last update, I have focused on two areas. The first area is the motor itself, and the second area is the support for the valve gear.
MOTOR
To date, the motor has been a place holder. I reserved a volume for the motor and placed the worm gear on a pseudo shaft. Yet the motor has electrical contacts, as well as other internals and is decidedly not just a reserved envelope. Time to resolve that. All of the motor details were taken directly from the Hanazono motor that I intend to use. The magnets, rotor and stator were drawn in. The electrical contacts were sketched, as well as the insulators. When placing the detailed motor into the chassis, I discovered that the motor envelope previously drawn was in error. The envelope was too long. Bank error in my favor! This resulted in a modest change to the chassis. I also modified the chassis to give room for a wire to come out from under the motor.
How to clamp the motor in place? The stator of the motor should not move relative to the chassis. I installed a wedge clamp (triangular wedge) at the inside of the smokebox face. The angle of that triangular wedge forces the upper front of the motor to the lower rear corner. At the lower rear corner of the motor are two chassis faces. Thus, the motor is locked into position via a diagonal force vector, upper front (on the left) to the lower rear (on the right).
VALVE GEAR SUPPORT
To date, all of the Stephenson Valve Gear has simply floated on location. Nothing supported it, it was never tied to OO Planet's structure. In my eye, it looked marvelous, but lurking there is a nasty problem. It is a mechanism that must be made to function, not just look pretty.
I begin with the valve gear axles. They are indeed tiny bits, brass, 0.5mm in diameter. They will be plenty stiff, as they are very short, just under 7mm They will be supported in 1mm OD, .225mm wall tube. That leaves 0.05mm clearance betwixt the axle and the tube, all the way around. a 0.002" slip fit. That is near perfect! Very good control of location whilst permitting rotation.
When you look at the image, note that there will be several axle supports across the front and across the back. They not only support the axle but keep the axle from floating side to side, as the valve gear bits on the axles are constrained. The first thing to know is that for any axle, the center line of these supports must be co-axial. That is fairly easy to accomodate, simply thread them onto a long axle when installing them.
That also goes for making them. There are always 3 parts to each support. The tube itself, an arm that permits longitudinal adjustment and a base. Note the base for the two outside supports in front is different from the others, because the cylinders and nominal base conflict. Indeed, Stephenson also had this problem, and I have followed his solution! The three components for each support will be mounted into a jig, simultaneously with the other axle supports, such that the longitudinal, or front to back distance is uniform and controlled over the set of supports. The jig will insuring co-axiality in manufacture. Whew.
And then I came to the most mind boggling problem of OO Planet so far. The length of the control rods, those diagonal struts running from front to back, is fixed. The control rods ride on axle rings mounted to control arms, with a specified clearance from the rod hole to the axle ring OD. It must not bind. The issue? The axle supports must be on vertical location. If they are too far apart, the control rod is too short and it will bind. If the supports are too close together, the control rod is too long, and it will bind.
It may look marvelous in CAD. Reduction to practice says otherwise.
BUILD UP OF TOLERANCE
This is a problem that occurs when we have multiple components in an assembly. Each tolerance adds to the next. This accumulates until the assembly may not function at all, unless the build up is considered and resolved. Where to tackle this? I studied the issue for days, experimenting with this and that. I could try for a precision placement of the axle supports, but I swiftly realized this wasn't going to be workable. After all, how tightly can I place these tiny bits! I decided on a vertical placement of the axle supports that I could achieve. And then looked for how to keep the mechanism from binding. What took an incredibly long time to realize was that relief from binding was in the control rods themselves.
LOOK TO STEPHENSON
Stephenson's Planet had threaded rods, such that the length of the rods could be adjusted. Stephenson had the same problem! I simply will not have the luxury of threaded control rods. It is all just too very small.
Approach 1 is to open up the inside bores on the ends of the control rods to account for the achievable vertical placement of BOTH front and back axle supports. That turns out to be a 0.11mm increase in the radius (0.004") or 0.008" total slop from the axle ring OD to the control rod ID. Not terrible, but the control rods may be a bit sloppy and as these control the oscillating handles, approach 1 is sub optimal.
Approach 2 is to make several control rods of varying length (in sets of 4). In placing the axle supports, the control rod range of lengths is defined. Pick the control rods that fit the realized model best. I can keep the ring OD to control rod ID tighter and substitute in a better matched set of rods, effectively taking Stephenson's approach. Approach 1 is presented in the image, although you will be extremely hard pressed to see it.
In the end, I will likely combine the two approaches. Various sets of control rods, with a tighter ID. The rods won't flop around and the mechanism will have good fitments, keeping friction lower.
These updates may not be visually obvious. The motor is buried inside the shell. The build up of tolerance solution is virtually invisible. Yet both took quite a bit of thought to accomplish.
Until Next update
Bee
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The word of the day is RAILWAY
Anna is a genuine voice from Ukraine. Today, the word was
залізниця
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Hiya JJ
The things you mention are NOT my worry.
My concern is the new marketing staff, a new CEO, and the short time to range launch. Range Launch a big effort, and the new team has gotten rid of Simon and Montana.
Bee
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Is there some way the mods can temporarily pin railway show notices? Once the show is over, the pin can go.
I just think that this kind of post deserves to be "on top". It is far too easy for a post to get buried. This one, in particular, may be 3 or 4 pages down by the date of the show.
Being in ROW, I will not be able to attend. But that doesn't mean others should not have the opportunity or notice.
Its just a thought.
Bee
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Discussion about price invariably reveals more about the commentator than it does about the "fairness" of the price. I happen to agree with LT&SR_NSE, "fair" is arbitrary.
It will always be thus. What is expensive for me, DRC seems to have the budget for. Attaboy DRC! You have marvelous stock, I am quite envious! 3Link is forthright in stating the prices are beyond his budget, but he still has loads of fun. Attaboy 3Link! Pride in making your own. I admire your skill.
I have pre-ordered R40357 for Queen Adelaide's Saloon, the other carriages are bonus but not required. £119. I have ordered R30090 for the Booth Curtain Carriage, the other kit is just a bonus. £242. Essentially £361 for two carriages. Or £181/carriage. Yes, I can afford it. Not complaining, at all.
Custom involute gears are ~£100 each. I have 10 on OO Planet. Did anyone hear me complain to the gear manufacturer that his prices weren't fair?
£66 / teak?
If you like the Teak carriages and they are in budget, buy them. The price will be long forgotten after you watch them on track, for years from now. If they last for 6 years, and why wouldn't they, that's £11 per year of enjoyment. Fairly inexpensive when viewed that way, eh?
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An amusing anecdote. Sam, of youTube fame, gives a score for an item's price. I can evaluate the price relative to my budget without his input and have mentioned that to him without avail. He has also stated repeatedly, that a locomotive seems too light in weight to justify the price. That is a very, very odd correlation. Under a recent video, I recommended that he state a price per pound (price per kilogram) number on each loco in a review, tongue in cheek. He replied that it seemed like a good idea. I cannot wait for this feature to begin!!
Bee
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Hi RT
I read your post and re-read it again. If anything, it was me not understanding the thrust of the comment, the core concept.
We are in agreement.
There is tremendous opportunity for Hornby to sell spares here. For models done in CAD, they have the shape. All they need do is print the part. A bit of fettling, a dab of paint and the enthusiast's problem is sorted. We would delight in getting a part for a 20 year old loco. The price would be a secondary consideration for an impossible to source part. Set up a technician with 50 3D printers at Margate. That program will pay for itself and likely become a profit center.
Bee
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Hi LT&SR_NSE
I dare not tell you of my 4 year program to build my monocoque personal water craft. I dare not tell you of the 16 year wisteria program in our garden which finally bloomed in the 15th year.
You are likely already aware that my OO Planet program will take quite a bit longer, as it is still in first pass engineering phase. I expect 2 more rounds of engineering before actual part acquisition occurs, followed by a ridiculously extensive build and test effort. How long will that be? 🤷♂️
Always remember the 5 Ps of Engineering. Prior Planning Prevents [redacted] Poor Performance. Now if I had only counted them ahead of time, I would have known there were six Ps. And yes, the redacted word was alliterative. Starts with P, and most assuredly banned!
Bee
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Hello Rana
I fully support your idea of making 3D printed components available to purchase. Hornby already have the CAD drawings. If I need a component, getting it 3D printed instead of molded is not going to stop my acquisition.
I do not think Hornby should ever release their intellectual property (the drawings) to the public. There is no control over how many 3D prints are made or control over where that drawing is spread. In my view, the Hornby crown jewels are the drawings of the models, not the models themselves.
Make the parts available? Full support. Sell copies of the IP? Not unless it is a going out of business sale.
Bee
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Hi DRC
That sensor Sam was clueless about appears very much to be a rotary encoder plate.
And I absolutely agree with your assessment, it is a tool to provide synchronization. The solution begins with a rotary encoder. The following writeup is my theory. Please note I have no insider information.
For those who do not know, a typical incremental rotary encoder has three channels. Sine, Cosine and Home. Sine and Cosine indicate direction of travel and with careful counting, where in travel. If the counting is measured against time, Sine and Cosine indicate velocity. The Home signal indicates a once per revolution reference.
Begin with Home. A CV in the decoder will indicate the delta between the arbitrary location on the rotary encoder and where top dead center of one wheel is. That is, the encoder need not be phased mechanically to the mechanism. Just plunk it on. We will install a programmable offset to adjust for the delta.
Another CV says how many chuffs per one revolution. Naturally, this is fixed. Divide the number of counts per encoder revolution by the number of chuffs. Thus the decoder knows exactly where each chuff is supposed to be, relative to rotary encoder position AND because the Home signal ties the rotary encoder to the valve gear, where each chuff is phased in relationship to the valve gear. This works for 4, 6, 8 or indeed any number of chuffs per revolution, software defined. There is nothing limiting you other than encoder resolution. You could even program crazy values, like 3.1415 chuffs per revolution!
Garrets and Big Boys may require 2 rotary encoders, as the timing between the two sets of drivers is not fixed. There are two sets of 4 chuffs, but the phase relationship between those two sets can change, wheel slip being a primary example.
With the velocity read from the rotary encoder, we know the duration of chuff. Running fast, short chuff. Running slow? Long chuff. Etc. So play the sound of one chuff at each chuff event, with the pointer increment into that sound file adjusted by the velocity. A sound file is a sequence of bits. Move the sequence pointer as a function of velocity.
So what about the regulator and the reverser? These effectively change the amplitude of the chuff. It could be a table of CVs that indicate for a given velocity, what the engineman would normal have these controls.
For arbitrary control, the decoder could receive inputs that declare what the enthusiast has the controls at and modifies the sound accordingly. That might just be a bridge too far for current technology. Feasible? Yes. The enthusiast would need a way to command these values, instead of velocity, the enthusiast would command regulator and reverser. It would put the enthusiast "into the cab". The enthusiast would drive just as the engineman would. The sound would be correct!
This works for a vast array of locomotives, making this near universal. The only thing to change would be the sound file of one chuff, per locomotive.
Bee
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In 5 short months, it will be the 9th of January. While some may call that the second Tuesday of January, Hornby will likely call that day "Range Launch 2024".
An important day for Hornby, Range Launch is when Hornby measures how the products selected by the Marketing team will sell. Many place their orders at the time of launch, including major retailers. For certain, I will be placing my pre-orders*
The selection process of what Range Launch 2024 includes has likely already started. Hornby are not going to wait until the night before to decide what products go into Range Launch. There is art work to create. Descriptions. Price rollups. A thousand procedural steps and internal gates.
The problem? Exactly who is the Marketing team? Simon -> gone. Montana -> gone. We may have one hint, Olly Raeburn, Hornby CEO, was Chief Marketing Officer at Paperchase before becoming CEO at Paperchase. Draw your own conclusions vis the previous occupants in role and how there may have been conflict.
Range Launch 2024 is coming. In 5 short months. After deducting weekends and my limited understanding of UK holidays, that is ~100 working days.
Sand pouring down the hourglass.
No pressure.
At all.
Bee
* Pre-order placement contingent upon content. If you have seen any of my scribblings, you know what I am after. But I do understand that other people will want other things. I wish good luck to everyone, that Hornby select and produce your dream kit.
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I recognize this is a long standing topic and many are quite passionate about it.
I do hope that this discussion is treated as intellectual discourse with truth being the goal. The truth will be found in the actual mechanism. I have no wish to upset other correspondents or ruffle feathers. Just to find truth.
Bee
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Hi 96RAF
We are in agreement. The reverser will affect the chuff because it affects cutoff.
There are 4 events for one steam port. Start of steam admission, end of steam admission (cutoff), start of exhaust and start of piston return.
To my understanding, start of steam admission begins at top dead center or thereabouts. Steam admission can be advanced or delayed by the reverser, but the degree of adjustment will be relatively small in relationship to piston stroke.
Steam admission ends at cutoff. The reverser affects the amplitude of the slide valve stroke. Depending upon the rate of flow of steam (regulator) and the time of cutoff, a certain pressure is achieved. That is, from start of steam admission, to end of cutoff, steam flows from one pressure vessel to the next. The duration of this period and the regulator constriction define how much steam, or pressure achieved in the destination vessel. The pressure achieved will affect the amplitude of the chuff.
The reverser does change the position of the slide valve with respect to the motion, primarily affecting the direction of the locomotive and cutoff. It does not change the relationship of the piston and wheels. Steam will be admitted at top of stroke and exhausted at bottom of stoke of piston.
The reverser will absolutely affect the sound. Solid agreement.
Where I think further clarity may be needed is the relationship of when steam exhaust occurs. That is the chuff and therefore important. Steam will be exhausted before the bottom of stroke of the piston. Examined logically, it cannot be after bottom, as the steam would then be compressed by the returning piston, decidedly inefficient! It will not be at mid expansion stroke, the steam will still be driving the piston forward, releasing the steam then would be wasteful. Indeed, I think it evident that for maximum efficiency, exhaust will occur as near to the end of stoke to permit enough time for the cylinder to reduce pressure, so as to not affect the return stroke.
Yet as the piston has mechanical linkage to the wheels, and it has been demonstrated that the exhaust is timed to the piston, it should be clear that the relationship of a chuff to a wheel orientation is relatively fixed. Exhaust occurs at end of piston stroke. Pistons are linked to wheels.
In my view, nearly all of this is icing on the cake. I do understand that others may perceive this differently. The reverser and regulator settings affect the sound only in degree. In my view, the fundamental issue is simply getting the correct number of chuffs and to have them occur at the relatively correct position of the wheels. Failing to get the fundamental correct makes the rest of it irrelevant. If you haven't got the correct number of chuffs for the velocity right, then of what use are the other modifiers?
Bee
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A shipper will mark down the item as "shipped" when the item has been registered with the carrier. NOT when that carrier has possession of the item. The shipper is waiting for the carrier to pick it up, so the shipper thinks the item "shipped"
Some carriers acknowledge that the shipment has been registered and that they are awaiting the item. Others will remain mum until the item is in the carriers hands.
This notorious gap was the subject of so much discussion and complaints on eBay, that eBay finally separated the categories. eBay penalizes a seller for "late shipments". So sellers were registering the item, avoiding penalty, but being quite slack getting the package to the carrier. This was facilitated by eBay, since the registration process is through eBay themselves. eBay finally split the status into two parts, the registration with the carrier and the carrier getting the package. Further, eBay estimates when your package will arrive based upon a quick turn around and normal transit times. So you have an expectation of your package showing up on or before that date.
Hornby's subcontracted shipping company is not so evolved.
Bee
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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.
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This thread warms my heart.
Attaboy TFOCH! Well done!
And I would like to see one of these pylons English Bob. After decoration, of course.
Bee
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I have encountered a reference which denotes the locations if Rocket's safety valves and names them as safety valves. There is no clarification as to the type of safety valve.
Treatise on rail roads and internal communications Thomas Earle 1830
The annotated drawing has a blob of ink right by the F, making it appear to be a P. The descriptive text, inset for convenience, does not include a P.
The other competitors at Rainhill are similarly illustrated and annotated, for those who are curious.
Bee
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Good mechanical approach to the issue. Using the hinge mechanism to support the plate could only function in the short term.
Another solution to the problem is a vertical lift railway bridge.
Not only is it a good access way, it is quite visually appealing to the mechanically inquisitive.
Bee
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Perfect spot for a pitch, Wapples!
Bee
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Thank you Three Link.
I must admit, this is not my first locomotive. Here is an image of some others I have worked on. It is an unusual scale for the enthusiast!
What scale is that? 1 😉
In the foreground, 4 Evolution AC4400 Locomotives, ready for shipment to the client. While they freewheeled to the client, 4 would provide ~670,000 lbf of continuous tractive effort. Up to 7 locomotives can be distributed throughout any one consist.
Extra points if you can identify the locomotive in the background and why it is mounted on a flat car!
Bee
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That's cherry picking evidence to support an already formulated conclusion.
To repeat
Of the 240 locomotives in the catalog, 110 are currently In Stock and will ship immediately.
A child will not be too fussed over era, livery or the "correctness" of running this wagon with that locomotive. They will just play trains.
Which they can do, right now.
It is only when the enthusiast narrows focus, selects an era and particular railway, does the waiting begin. Certainly, you have witnessed the discussions about the order of the carriages, where the restaurant car was, etc. Those are decidedly not a child's conversation.
The child will just play, with whatever they have.
Bee
Current L&M 3rd class coaches
in General Discussion
Posted
Hi 81F
I've posted your requested picture.
I took the opposite approach. I converted my old Triang carriages (Times, Experience and Despatch) to the modern chain link couplings and dispensed with the tension lock couplings. That includes the Triang tender, which brings the older Rocket up to modern standards.
Your mileage may vary, of course.
Cheers
Bee