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Post by GeorgeRay on Aug 14, 2014 11:51:48 GMT
Strictly they are not Boxpok wheels which have box section spokes hence the name, they are BFB (Bulleid Firth Brown or Beaumont Firth Brown) which are different.
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Post by Deleted on Aug 14, 2014 14:50:08 GMT
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Post by Deleted on Aug 14, 2014 14:51:11 GMT
oopss!!ERROR !
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Post by Deleted on Aug 14, 2014 14:51:55 GMT
and again........
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Post by Doug on Aug 25, 2014 14:37:41 GMT
Been making steady progress with this and it's upping my game a bit with the 3d cad, I have found a few bits that need changing already it's great to build it in CAD and see how it fits together, The rear buffer frame is a bit big and the axle boxes need a slight mod underneath but so far so good I don't think I will be too far off when I said it would take a year to do all the drawings there are soo many parts it's unreal!
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Post by austerity on Aug 25, 2014 15:17:35 GMT
I don`t think Bulleid built them as air smoothed,I think it was intended that they could be put through the carriage washing plant,it would certainly save a lot of work!!!
Ray.
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Post by donashton on Aug 25, 2014 19:44:17 GMT
Glad to see your progress and wish you well. It is a mammoth job to do the drawings, as you indicate, but it should be of immense satisfaction. I'm buried in drawing the full size 4709, keeping well ahead of the contractors. I'd be interested to know if you are to follow Bullied's valve gear, which was quite excellent and avoided the usual 3-cylinder problems, just as long as the drivers managed to stop the steam reverser wandering about! Best wishes, Don.
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Post by Deleted on Aug 25, 2014 21:12:40 GMT
We had a driver years ago at the Bluebell who claimed to have cured the wandering reverser problem, the intrigued workshop staff inspected the cure and promptly went skybound. The driver had simply wedged a spanner between the indicator pointer and the cab framing, the reverser had of course still wandered and bent all the indicator linkages while it had done so! Said driver was severely reprimanded!
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Post by Doug on Aug 26, 2014 5:28:47 GMT
I am going to use a gear box as per all the rebuilt light Pacific's and I am copying and reducing the valve gear from Auriel 5" as this just happens to be a Battle of Britain class NOT a merchant navy which works out very well for me. Regarding the center cylinder I haven't figured it out yet as I haven't had a look at the rebuilt valve gear. I am having to make some small changes because of the scale to the axles and axle boxes etc. wow Don that's quite a project you have taken on there. What a lovely loco
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Post by Deleted on Aug 26, 2014 10:07:05 GMT
Hi Doug,
Don't know if you have noticed but although the inside cylinder is normal inside admission, the outside cylinders are outside admission. No big deal if you are going to use piston valves but a few changes would have to be made if you wanted to change the outside cylinders to inside admission.
Out of interest I'm just looking at the Ariel valve gear to see what it's like.
John
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Aug 26, 2014 10:35:54 GMT
hi doug,
if you like the look of the fullsize GWR 47XX project that Don is heavily involved in designing then a 2.5"g or 3.5"g 47XX would make a lovely loco and a few have been built in these gauges.
personally, i start with deciding how easy the boiler is going to be to build and whether there is easy access to the cab controls and how long the tender is going to be to lean over to get at the controls and fire the boiler. i dont like sloping grates, small locos where you cant drop the ashpan and grate, or tapered barrels or combustion chambers. ive one GWR loco with a tapered barrel, belpaire firebox that narrows towards the rear, and long narrow sloping firebox, and although its a lovely loco it's not easy to fire or drive, and the axleboxes under the ashpan have worn very badly. i dont fancy making another one of this type!
i do like the rebuilt SR Bulleid pacifics though!
Ben's comment is very interesting re the reverser on the unrebuilt locos. when tested at Rugby in the early 1950s they clamped the reach rod but the original chain driven valve gear still produced wild random and unexpected results and sudden bursts of power especially if notched up.
cheers, julian
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Post by Deleted on Aug 26, 2014 12:01:49 GMT
Must admit I do like the GWR tank locos. I started drawing up a 7200 2-8-2 for 2½" gauge. That would make a nice big loco in that size!
I've had a quick look at the Ariel inside valve gear and it seems to me that the combination lever dimensions (as given in the ME articles) are incorrect, both for the inside and outside valve gears. The inside dimensions give negative lead and the valve doesn't open at all in the shorter cut offs. I've had a look through the list of known errors and there doesn't seem to be any mention of this. Maybe the full size drawings are different? Keith Wilson says that he carefully scaled the valve gear from the full size works drawings but I wonder if he scaled the port and valve head dimensions as well. Maybe not.
John
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Post by Doug on Aug 26, 2014 12:05:29 GMT
Hi Doug, Don't know if you have noticed but although the inside cylinder is normal inside admission, the outside cylinders are outside admission. No big deal if you are going to use piston valves but a few changes would have to be made if you wanted to change the outside cylinders to inside admission. Out of interest I'm just looking at the Ariel valve gear to see what it's like. John wow thanks John i havent got that far yet though i am working in a bit of a cyclic mannor at the moment build a part (in 3D) then fit it and see how it works/ fits with other parts then go back and alter the 2D drawings to make it fit/work i have only done the mainframes, dragbox, axleboxes and horn guides, front buffer and plates, smoke box and chimny, driving wheels and axles, now getting stuck into the bogey and frames, i have alot of work to do on the strechers and motion brackets before i tackle the cylinders. quite a bit of it will need to be simplified with just the outward aperance of the original i think. Great fun though
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Post by Deleted on Aug 26, 2014 12:15:41 GMT
Hi Doug,
Yes, I would have simplified it a lot if I was to ever build one. The motion brackets etc. would be nightmare to fabricate in this scale if you wanted them to look authentic!
As I've mentioned before, it was really just an exercise to learn the Alibre 3D software rather than a working design. I've just bought the latest version and it's nice to see that some of the things I didn't like about it have been improved no end. What 3D software are you using by the way?
John
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Post by Doug on Aug 26, 2014 12:17:33 GMT
hi doug, if you like the look of the fullsize GWR 47XX project that Don is heavily involved in designing then a 2.5"g or 3.5"g 47XX would make a lovely loco and a few have been built in these gauges. personally, i start with deciding how easy the boiler is going to be to build and whether there is easy access to the cab controls and how long the tender is going to be to lean over to get at the controls and fire the boiler. i dont like sloping grates, small locos where you cant drop the ashpan and grate, or tapered barrels or combustion chambers. ive one GWR loco with a tapered barrel, belpaire firebox that narrows towards the rear, and long narrow sloping firebox, and although its a lovely loco it's not easy to fire or drive, and the axleboxes under the ashpan have worn very badly. i dont fancy making another one of this type! i do like the rebuilt SR Bulleid pacifics though! Ben's comment is very interesting re the reverser on the unrebuilt locos. when tested at Rugby in the early 1950s they clamped the reach rod but the original chain driven valve gear still produced wild random and unexpected results and sudden bursts of power especially if notched up. cheers, julian Hi julian I know the boiler on the Bulleid will be an absolute Horror to build in its current form i dont think i have ever seen one as complicated i will have to see if it can be made or if i go for a simple version inder the clothes the whole loco is a very very complex but then that is what i was after, although i love detail i may have to conseed that somethings just wont be practicle in 2.5" so i will take a sensible aproch to what i can and cant do. even if this ends up as a model only (i doubt this would happen tho) i am determined to build it, i have always loved the Big loco's with tenders and i already have two tank loco's of which i think once finished my Speedy will be the work horse, I will have a "propper loco" if its the last thing i ever do. the one thing that i always keep in mind is you can always rebuild any part you want any time you want to so you cant ever say its finished, even the full size got rebuilt many times over and still do. the old merchant navy loco's seem to have been a little characterful i keep hearing the same story's
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Post by Doug on Aug 26, 2014 12:25:27 GMT
Hi Doug, Yes, I would have simplified it a lot if I was to ever build one. The motion brackets etc. would be nightmare to fabricate in this scale if you wanted them to look authentic! As I've mentioned before, it was really just an exercise to learn the Alibre 3D software rather than a working design. I've just bought the latest version and it's nice to see that some of the things I didn't like about it have been improved no end. What 3D software are you using by the way? John i am using Autocad 2011 its been a bit of a steep learning curve TBH, i did my training on Autocad 11 (bout 1998) thanks to a certain club member for that one!! i have used 3D infequently since with Autocad 2001 and 2004 but nothing too serious mostly 2D cad for Shop layouts and machine panel design & circuit etc. i have to say its alot easier now than when i first did some 3D cad with Mr Banton! I was thinking to make the motion brackets from solid on the CNC but i wont know how doable this is till i get them drawn on the CAD. that way i will get the look and detail i want without the fiddly silver soldering.
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Post by masahiraoka on Aug 27, 2014 20:18:51 GMT
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Post by Deleted on Aug 27, 2014 21:42:19 GMT
People are asking that much for 5" Brits nowadays. A good Merchant Navy has to worth more than a Brit so the price seems reasonable to me. It will be interesting to see what this one actually sells for. I reckon quite a bit more than the estimates.
John
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Post by masahiraoka on Aug 28, 2014 8:28:31 GMT
John I agree probably low to mid twenties
martyn
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Aug 28, 2014 9:19:10 GMT
hi martyn, the late Mr Holden's Merchant Navy in the Dreweatts auction has never been steamed. before parting with a large sum of money for anything other than a glass show case 'model', any purchaser wanting a reliable efficient loco that performs well on the track should always ask for a drive on a club track with a decent load. then, £15,000 might be appropriate in such circumstances. given the very well known problems and defects with the Keith Wilson ARIEL design, i would be very surprised if anyone paid £15,000 for an unsteamed and untried loco of this type, unless they want to be very disappointed! 'all that glistens isnt gold'. i also note that the loco sadly has very plain and basic commercial boiler fittings. of the few locos ive sold that ive built, the prospective purchaser has always been very familiar with the locos' performance and driven same beforehand, and knowing that the purchaser is going to take good care of the loco and run it has always been a factor in any decision whether to sell! cheers, julian
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