Getting sufficient weight into smaller tender locos is a factor on which Hornby have recently made good progress. They have achieved this by casting much of the loco bodies in metal, so that the recent smaller tender loco models I have purchased (B12/3, D16/3, J15) are all tractively very competent due to weight alone. There's no losses in appearance compared to a plastic injection moulding either, just as refined
Hopefully other manufacturers will take note. It's certainly a good plan for those compact main line locomotives like the 43xx, where volume for inclusion of weight is limited, and especially where there is a taper boiler to take into account. (Also for some not so small locos, the Stanier 8F could really use this technique, as it is far too light in plastic bodied form.)
Bachmann 43XX split chassis issues
Re: Bachmann 43XX split chassis issues
43xx/ Airfix Prairie motor replacement
The Prairie motor shaft is 90thou (2.28mm) but the Hornby Prairie and the Grange have a 2mm shaft and flat can motors that are 20x15. Both the Hornby worms appear the same but a slightly smaller pitch than the Airfix. I think they are close enough to be used. The problem is the motors will not fit between the Prairie wheels.
Smaller motors only have a 1.5mm shaft so to use a Hornby worm would require a 1.5-2mm sleeve. (Available from Nigel Lawton). But the Hornby 14xx appears to have the same pitch worm and a 1.5mm shaft, this may well fit between the wheels.
All the locos with ‘can’ motors have at least one intermediate gear to decrease the gearing further so a direct worm drive is likely to be very fast.
The Grange motor is a 5 pole skew wound motor but cannot be fitted into the Prairie as the flanges are on a different ends, which is a shame. (Ie. The Grange has the large flange on the drive end, and the Prairie has it on the terminal end).
I found a Bachmann Collet motor and frame, with the same pitch worm as the Airfix Prairie. (It was removed when the Collet was converted to a tender drive). This was SuperGlued in place of the Airfix motor. The weights were changed to 90g rear and 36g front. The final weight, without the front bogie/pony truck was 233g.
The resultant gearing is too high, it would give a Bullet train a run for its money! About half throttle is as far as you need to go but considering this, the low speed control is very good. I expected a better noise reduction but it is only about 50% less so the chassis is making as much noise as the motor!
I then discovered that the rear wheels had a lot of slack, I stuck a 10 thou piece of plastic to the under frame but this was a bit too big and had to be filed down until the wheels moved sideways freely. This has improved the running.
The Prairie motor shaft is 90thou (2.28mm) but the Hornby Prairie and the Grange have a 2mm shaft and flat can motors that are 20x15. Both the Hornby worms appear the same but a slightly smaller pitch than the Airfix. I think they are close enough to be used. The problem is the motors will not fit between the Prairie wheels.
Smaller motors only have a 1.5mm shaft so to use a Hornby worm would require a 1.5-2mm sleeve. (Available from Nigel Lawton). But the Hornby 14xx appears to have the same pitch worm and a 1.5mm shaft, this may well fit between the wheels.
All the locos with ‘can’ motors have at least one intermediate gear to decrease the gearing further so a direct worm drive is likely to be very fast.
The Grange motor is a 5 pole skew wound motor but cannot be fitted into the Prairie as the flanges are on a different ends, which is a shame. (Ie. The Grange has the large flange on the drive end, and the Prairie has it on the terminal end).
I found a Bachmann Collet motor and frame, with the same pitch worm as the Airfix Prairie. (It was removed when the Collet was converted to a tender drive). This was SuperGlued in place of the Airfix motor. The weights were changed to 90g rear and 36g front. The final weight, without the front bogie/pony truck was 233g.
The resultant gearing is too high, it would give a Bullet train a run for its money! About half throttle is as far as you need to go but considering this, the low speed control is very good. I expected a better noise reduction but it is only about 50% less so the chassis is making as much noise as the motor!
I then discovered that the rear wheels had a lot of slack, I stuck a 10 thou piece of plastic to the under frame but this was a bit too big and had to be filed down until the wheels moved sideways freely. This has improved the running.