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Post by Rob on Oct 12, 2014 20:28:57 GMT
I have been looking forward to an update of this thread, the detail is exceptional!
I presume that you'll be making these commercially available, do you expect the extra detail to push the price up much beyond what we're accustomed to with the 'old' style castings?
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Post by suctionhose on Oct 12, 2014 21:46:39 GMT
I've been forwarding some your photo's to my son who is studying mech eng. He, and other like him at the beginning of their careers have not had the experience of producing parts to see the value of "no tooling".
Your work is extremely educational. You should considering speaking at engineering forums about it.
Separate question: Models require as much extra weight built in as possible to provide adhesion. With the castings being fully cored etc, do you expect the finished model to be significantly lighter than traditional? How would you compensate for that?
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44767
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Post by 44767 on Oct 12, 2014 22:40:48 GMT
I have been looking forward to an update of this thread, the detail is exceptional! I presume that you'll be making these commercially available, do you expect the extra detail to push the price up much beyond what we're accustomed to with the 'old' style castings? Certainly these will be available to purchase. The models I am producing are to prove the design and drawings are correct which I think is important so that builders can be confident about starting to build one. As explained earlier in the thread I am aiming to have 100% accurate drawings but if amendments are needed I would do a revision to the part and its drawing and issue these to anyone who has purchased the drawings. As far as priced go, lost wax castings will always be more expensive than sand castings but I am trying to keep the cost of my castings low enough to make this model attractive to build. These castings will save many hours machining time compared with crude sand castings available at the moment from some suppliers. Compare the sand cast piece in the background here with the pictured in my last post.  What's more, this model takes accuracy to a new level having been designed from works drawings but it doesn't make it much more complicated to build. Mike |
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44767
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Post by 44767 on Oct 12, 2014 22:49:46 GMT
I've been forwarding some your photo's to my son who is studying mech eng. He, and other like him at the beginning of their careers have not had the experience of producing parts to see the value of "no tooling". Your work is extremely educational. You should considering speaking at engineering forums about it. Separate question: Models require as much extra weight built in as possible to provide adhesion. With the castings being fully cored etc, do you expect the finished model to be significantly lighter than traditional? How would you compensate for that? Very kind words, thank you. I'm happy that this thread is attracting a lot of interest as it was always about using new techniques and applying them to our hobby. It's a good point about the weight issue. The starting point is to make the model as accurate as possible and then, if extra traction is required, the builder could add weight wherever necessary. It would be and easy thing to model in lumps of lead which could be concealed inside the tanks etc. The other way is that the true scale stretchers could be replaced by crude bar type stretchers for increased weight using the same dimensions. I always thought it would be an option to produce a semi scale frame like this to increase weight for those who wanted to save time and a bit of cost. I'm concentrating on the true scale first though! Mike |
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Post by suctionhose on Oct 13, 2014 1:26:11 GMT
Thanks for the reply. Understand and completely endorse your primary objective over the weight issue.
If anything, being in a position to retain thin sections where heating occurs eg cylinders, and applying weight where required for adhesion is an ideal situation.
Out of interest, one time I attended the local Mech Engineers Chapter to hear a talk on the digital era, 3D printing etc.
The ability to make a new knob for your toaster is rather less captivating than what you're doing there!
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Post by ejparrott on Oct 13, 2014 8:00:58 GMT
Its something David and I have discussed at length with his 9F. In his quest for accuracy, Les' 8 or so crude stretchers are being replaced with 24 scale stretchers. It's going to look superb when it's done, and the materials for the stretchers weigh in somewhat...well..they do before he starts machining them! We are slightly concerned that the correct number of stretchers are going to be lighter than Les' design, but we'll worry about it later. We both have a very keen interest in GL5, and I've suggested building the tender suitable for using to drive from, with footrests under the engine's cab, so a little extra weight can be added when she slips. The sandboxes may be made from solid to increase the weight, or they may be made to work..yet to be decided!
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44767
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Post by 44767 on Oct 13, 2014 11:24:46 GMT
I don't think Dave's 9F will suffer for having the correct stretchers. It will be much nicer from a model point of view to have them looking right. They are quite visible on the 9F so extra effort with them will be worth it. As you say, sand boxes could be solid or filled with lead and the extra weight from a pair of full size boots on the foot pegs is probably all you'll need. I had a beautifully made "Maid of Kent" which ran perfectly but when I bought it from the builder (he gave up driving it at 83 years old) I asked what was with the worn patch of paint on the cab roof. He replied that it was him leaning on the cab to get more traction when pulling passengers up our 1:50 climb to the summit!
I'm thinking along the lines of some form fitting lead castings which can be placed inside the frames if necessary for hauling but easily removable for when the model is on display. I'm keen on the GL5 scene too and I guess this loco's job would be small freight trains and maybe empty stock working/ station pilot so not too much pulling power required anyway.
See you on Saturday, Ed?
Mike
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Post by ejparrott on Oct 13, 2014 12:08:02 GMT
Yes mate I'll be there, stewarding so on the stand at least half the day, bringing a box of all the bits I've made but not fitted to the engine too.
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Post by Rob on Oct 13, 2014 12:53:01 GMT
I'd very much like to build a reasonably accurate 9F as a long term future project, in 7 1/4" gauge, though I'd be happy with 5" if the larger scale proved beyond my reach.
I understand that a number of the parts are interchangeable, so I would definitely be interested in the lost wax style castings. Presumably, if enough of the common standard parts are produced, a number of different classes could be made!
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Post by vulcanbomber on Oct 13, 2014 17:49:38 GMT
........ I'm thinking along the lines of some form fitting lead castings which can be placed inside the frames if necessary for hauling but easily removable for when the model is on display.
............... That, funny enough has crossed my mind..... My 9F when its built will be made to earn its keep (Ed's challenged me to drag the club chairmans pair of diesels, I forget the class, backwards with the 9F) as well as look as close to the real thing as reasonably possible when its not running so semi hiding some removable weight when its not in action would be handy. |
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sis
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Post by sis on Oct 13, 2014 18:39:57 GMT
Mike, I've just found this thread. This is a wonderful build thread. Very inspirational and educational. A joy to follow. i am a bit bemused - did you say you were building 10 of these locos? is this a commercial venture? cant myself understand why you would want one BR std loco when compared with a GWR loco let alone 10!! very nice work though and very impressive! cheers, julian It also made me laugh out loud, thanks to that comment from Julian! Regards, Steve |
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Post by fostergp6nhp on Oct 13, 2014 19:46:26 GMT
For extra weight how about split cylindrical weights clamped around the axles between the axleboxes, it adds weight directly to the driving wheels without adding extra load to the axle bearings.
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Post by vulcanbomber on Oct 13, 2014 19:48:48 GMT
For extra weight how about split cylindrical weights clamped around the axles between the axleboxes, it adds weight directly to the driving wheels without adding extra load to the axle bearings. Idea's like that will get you in front of Ed in the Queue to drive the 9F...... |
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44767
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Post by 44767 on Oct 13, 2014 22:23:23 GMT
For extra weight how about split cylindrical weights clamped around the axles between the axleboxes, it adds weight directly to the driving wheels without adding extra load to the axle bearings. This probably would work for the model but in full size it was not good practice because of all the unsprung weight which is not good for the track. There is a fascinating book about the development of the APT which, although itself was not a starter, lead to technologies used on later designs including having the motors mounted on the frames which drove the axles via transmission shafts. Also the design of bogies was covered which allowed them to predict at what speed a design would start "hunting". " Hunting is dangerous because the harmonics set up between the springing and wheel tread/track profile cause the bogie to move side to side quite violently. So they were able to design a bogie that would not start hunting until beyond its expected top speed. Very soon after reading this book I was in a Mark 1 carriage (speed limit of 90mph) with standing room only in the corridor which was being hauled up the West Coast line near Carlisle when this hunting started. Well what's the point of showing concern? Nothing I could do about it! Sorry, a little side tracked but interesting; find the book, have a read. Mike |
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jma1009
Elder Statesman
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Post by jma1009 on Oct 13, 2014 22:48:23 GMT
contrary to the late jim ewin's theories and those of the late johnny seymour,
ive always found that a good fullsize design when scaled down performs at it's optimum without addition weight. if you add additional weight you risk the loco performing above it's optimum level of performance. ok, it will pull more and wont slip, but it is being pressed much harder than optimum with increased coal and water consumption.
if, as in mike's case, and vulcanbomber's 9F you incorporate all the missing bits from 'ordinary' miniature designs, the weight soon creeps up without affecting optimum performance. ive added lots of genuine extras as per fullsize to Stepney and what i originally envisaged as a nice light loco to sit on top of the piano when not in use is going to be far too heavy for the top of the piano!
cheers,
julian
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Post by suctionhose on Oct 14, 2014 5:49:37 GMT
Suspension and weight distribution have a great bearing on traction. 2-6-2 sounds well balanced but prone to losing traction in a hollow. Will be a trick to have sufficient weight / travel on bogies to prevent derailing, or leaving the track on a hump.
What the owner / driver feels is satisfactory adhesion is a personal matter.
Me, I enjoy a long slog so lead wherever its invisible!
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Post by Cro on Oct 15, 2014 8:50:02 GMT
contrary to the late jim ewin's theories and those of the late johnny seymour, ive always found that a good fullsize design when scaled down performs at it's optimum without addition weight. if you add additional weight you risk the loco performing above it's optimum level of performance. ok, it will pull more and wont slip, but it is being pressed much harder than optimum with increased coal and water consumption. if, as in mike's case, and vulcanbomber's 9F you incorporate all the missing bits from 'ordinary' miniature designs, the weight soon creeps up without affecting optimum performance. ive added lots of genuine extras as per fullsize to Stepney and what i originally envisaged as a nice light loco to sit on top of the piano when not in use is going to be far too heavy for the top of the piano! cheers, julian Julian, speaking of Jim do you, or does anyone know the location of his 9f "Load Star" I heard many thing about it as my dad saw it during its build but I have never seen it and I haven't come across anyone that who's of its whereabouts. Also I have a 9f that I have recently got running for the first time, it started life as a Winson kit but now is very much far from it but is based on the Warnet drawings and I can tell you its heavy enough for pulling a good load. On its first couple of test runs we did a few load tests with some of our rolling stock and the last one we did it was pulling just over 3/4 ton of rolling weight with no problems and this is without any extra weight added and it seemed fairly efficient so far but hard to tell that on a few test runs, I imagine when finished and running it will pull a large load no problem. Cheers, Cro |
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jma1009
Elder Statesman
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Post by jma1009 on Oct 15, 2014 9:01:14 GMT
hi cro,
im afraid i dont know where jim's 9F is these days, but know the whereabouts of his famous 0-6-2T loco and his SR Schools class loco.
i remember seeing jim's 9F hauling a huge number of passenger trolleys full of kids and adults, with jim as ever in customary white coat.
it is perhaps an interesting observation that of all the boilers ive built they all 'balance' weight wise where the throatplate is.
cheers,
julian
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Post by Cro on Oct 15, 2014 9:20:15 GMT
Julian,
Thanks for that, real shame as I am determined to find the loco as I have heard some fantastic things about it.
Also Mike loving the work on the Class 3 looking forward to seeing some bits at the weekend.
Cro
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44767
Statesman
Posts: 538
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Post by 44767 on Oct 28, 2014 14:45:02 GMT
For those of you who I met at the show, it was very good to see you. For those who were not able to meet up, sorry about that but no doubt there'll be another chance later. I am just about to board my flight home and I am looking forward to making a lot of progress on the models tomorrow! For the record, there are now five models accounted for and there is one being built now in parallel with mine as I progress. So it was worth coming here if only for a very short time.
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