Barrelling along the track (part 2).

… continued from https://philbarber2.wordpress.com/2022/01/09/trackconics/

To validate the conical wheel stabilty (mathematical) model I turned the system engineering paradigm of : requirements capture; targets cascade and components design intent on it’s head and searched for the biggest lump of something I could turn in the lathe.

A forray round the estate unearthed the following.

1. A large log of elm that someone without the heart to burn it had given me about five years ago and has been in the garden ever since.
2. A leg off an (Ikea?) table made of oak blocks glued together.
3. A lump of redwood that had hung down as part of he bannisters until it got in the way of the front door curtain.

Starting with the last, it was slowly rounded off to 3.3/4″ in diameter by 6″ long.

at this point it would fit over the saddle in the lathe and with the cross slide set over by 5.7 degrees the ends were taken down to a 1:10 taper. This gave a 3.1/32″ end diameter and a 3.5/8″ centre for a 6″ long barrel. Applying this to a 5″ gauge track should give a wavelength of 39″.

The sleepers on this test track are 3.1/4″ apart and from freeze frame images the wavelength can be seen to be 12 sleepers or 39″

Sleeper 17 : Displaced to its left.

Sleeper 11 : Displaced to its right

Sleeper 5: Displaced to its left again.

[a longer video of the barrel on a 3.1/2″ gauge track is on youtube]

https://youtube.com/shorts/bgOAEPsA7kI?feature=share

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The leg from the Ikea table was similarly turned down to a 12″ long spindle, 2″ diameter in the centre and with a 1:20 (2.87 degree) cone angle. This giving a 1.400″ diameter at each end.

On 5″ track, this should give a wavelength of 41.5″

Sleeper 17: Displaced to its left.

Sleeper 11: Displaced to its right.

Sleeper 4.1/2 : Displaced to its left again.

This shows the wavelength to be 12.1/2 x 3.1/4 or 40.3/8″

The log of elm will have to wait for another day.