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Post by steamjohn248 on Apr 7, 2007 21:02:34 GMT
We are getting to grips with our 1/3 scale L and B "TAW" and although the Milner Drawings show all three sets of drivers with flanges, The one we recently borrowed had the centre drivers flangless. I'm familiar with the tyre profile on such as the 9F (full size) centre drivers but has anyone any comments on NG profiled flange less wheels in 7 1/4". Although our railway has 60' min radius curves we think it would make the loco more versatile and would be interested in comments from other operators. (Wheelbase is 26" over the drivers).
Cheers
Steamjohn
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Post by Shawki Shlemon on Apr 8, 2007 11:08:33 GMT
As I have red in many articles about tracks and rad. , I believe the minimum radius required for free operation is rigid wheel base X 20 . In your case this will be a radius of 44 feet .Having said that the flange less centre wheels will do no harm .
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Post by steamjohn248 on Apr 11, 2007 19:47:21 GMT
Thanks Shawki, Flangeless centre drivers it will be but.......
Has anyone ever actually done this and if so what did you use for a tyre profile, in the real thing there is a slight 'doming' of the tread, a bit like and old fashioned flat belt driving flywheel but I've never seen enything published in the model press about the subject. Common sense dictates that an ordinary tread profile a la 7 1/4" soc, rules minus the flange would not work as the wheel would need to climb back onto the rail head from either direction.
This forum is never lost for an answer surely.
Steamjohn
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Post by havoc on Apr 11, 2007 19:54:33 GMT
If the real thing was slightly "domed" then why not in scale. The only reason I could see is that in 1:1 the rails are slightly inclined to the center while in scale installations they are mostly with "flat" tops.
Very interesting point anyway. I never tought of flangeless drivers having a profile.
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Post by chameleonrob on Apr 11, 2007 20:21:30 GMT
If you think in terms of the axle rather than just each wheel then turning a (say) 3o cone on each tread then the axle will behave like a domed driving fly wheel, albeit with the (unused) middle bit cut out. If I remember rightly then the back to back dimension was smaller on flangeless drivers.
rob
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Post by Shawki Shlemon on Apr 12, 2007 9:37:38 GMT
I had two sets of wheels ( that is second and third axles ) on 2 - 8 - 2 tank engine in 5" G flange less with 2 degrees cone on the tread and I had no problem with the engine at all while I had it.( that is before was stolen ). The engine in question was SMR 10 you can view a short video clip for it on my website .
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SteveW
Elder Statesman
Posts: 1,397
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Post by SteveW on Apr 14, 2007 23:59:45 GMT
John,
Just to add to your dilemma, just watched "Back to the Future III" on the box. Set in the US 1880 old west was a 4-6-? loco with the middle drive wheel having a parallel tread.
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Post by spurley on Apr 15, 2007 0:33:00 GMT
Better than that, have a look at the 'flanges' on the 14XX that gets liberated by Ned for the Titfield line after theirs has been wrecked by Pearce and Crump! Don't know what standard they comply with;D
Believe it was a Fordson truck witha a mock up body.
Cheers
Brian
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Post by alanstepney on Apr 15, 2007 6:09:36 GMT
The Pearson 4-2-4, had, obviously, one pair of driving wheels, which were flangeless.
From the photos and drawings I have seen, they do not appear to have any taper.
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