Hornby 9F

"Rob" wrote

The 9F will *probably* negotiate first radius curves, so that is not an issue - there's loadsa slop in the non-powered driving wheels. Buy one of the latest 5-pole motor (still in tender I'm afraid) jobbies and use a decoder with both back-emf and silent drive.

Then find room in the tender to fit it! :-)

John.

"44211" wrote

Hi Ray,

Nothing at the moment that I've heard of. It's not so long ago that Hornby revitalised the 9F by improving detail (and dropping the height of the boiler from memory) and it hasn't been a massive seller since then. Of course it might have been different had they converted it to loco drive at the same time. :-)

John.

I have one of the very early ones (the rare black version, 92166, from ca. 1972 [1]), which was bought 2nd hand but still runs very well. I don't know if the new improved 9F is the same, but older versions had articulated coupling rods which, together with the authentic (for once!!) flangeless centre driver, meant that the loco negotiated sharp curves (as sharp as 1st radius sectional track, at least) very well. The only major fault of older 9Fs is that the body sits a bit too high on its chassis compared with either the prototype or the Airfix/Dapol kit.

David E. Belcher

- so it shouldn't really have the BR Standard step-sided tender!

Rob, I have 92134, Runs OK on ZTC with a Lenz chip, but be warned, tight curves cause the axles to slide and when run in low light (or dark) you can see sparks where the rods are shorting out or some reason ! I still don't know why, but there is something not insulated !!!

Andy

It's possibly due to one of the wheel wiper pickups not working properly - the motor current is finding an alternative path from one wheel, through the side rods, to the other pick-up wheel and then the wheel wiper on the same side. Any loco with a rigid frame is effectively an 0-4-0 with only three wheels on the track at any moment. (ignoring the bogies or pony trucks)

Regards, Greg.P.

Gregory Procter wrote:-

What if it's running on flexible track?

(kim)

I guess you would get all four wheels carrying weight and collecting if the track was vertically flexible by way of the weight on the loco wheels - it would need to be about as flexible as blancmange though to get all eight 9F drivers collecting! (yeah, I know there are ten, but only eight have wipers) (and yes, the middle two will collect current via the side rods)

Regards, Greg.P.

Gregory Procter wrote:-

Is the Comet chassis compensated in any way?

(kim)

That depends on how you build it! Keith

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"Gregory Procter" wrote (and yes, the middle two will collect current via the side rods)

I think this may be the problem, although I struggle to see why. I haven't run it for a few weeks, but memory serves, it was to do with which way it went around the corner (i.e. a left hand bend) and the wheel touching the chassis, shorting and tripping out the ZTC 511 as an overload :-(

I will have a look in the next few days and report back with findings....It was 2nd rad curves by he way (and 3rd)

Current will always take the path of least resistance - if the flangless wheel is carrying the weight of that side and the other four wheels are almost/nearly/just touching then the flangeless wheel-rod-wheelrim-wiper is the route it will take.