Author Topic: Alyn Foundry Nattie  (Read 4307 times)

Online Admiral_dk

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Re: Alyn Foundry Nattie
« Reply #75 on: January 13, 2023, 04:07:56 PM »
So it actually works like a Scotch Yoke - simple, elegant and most likely very reliable  :ThumbsUp:

Per            :cheers:

Offline Alyn Foundry

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Re: Alyn Foundry Nattie
« Reply #76 on: January 13, 2023, 07:05:21 PM »
Possible inspiration ??  ;)

You’re definitely going to need those flywheels now Ray.


<a href="https://www.youtube.com/watch?v=beIW4E4Emmk" target="_blank">http://www.youtube.com/watch?v=beIW4E4Emmk</a>

 :cheers:  Graham.

Offline RayW

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Re: Alyn Foundry Nattie
« Reply #77 on: January 13, 2023, 07:54:04 PM »
Still a few more bits to do yet Graham. Have just ordered some 2 thou shim for the exhaust valve.  Also need to sort out lubrication for the big end as I have used a split brss bearing. Then of course, there are a couple of non-standard extras to be made!
Ray

Offline RayW

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Re: Alyn Foundry Nattie
« Reply #78 on: January 24, 2023, 07:48:24 PM »
Some time ago, Graham suggested that it would be fun to add a mechanical oiler to Nattie to replicate the ones fitted to the full scale National engines. As a complete novice user of Fusion 360, I thought it would be an interesting project to try and design and build one. The photos show the (almost) finished end result, just lacking the full outlet pipe, which will drip oil into the cylinder, and a drive belt to provide drive from the side shaft.
For those not familiar with this type of oiler, the drive pulley is connected to a small crank on the end of which is a short length of chain. The bottom of the reservoir is filled with oil, through which the chain is dragged as the crank revolves. The oil trapped on the chain is scraped off on a slanting length of rod, below which is a cup into which the oil drips and runs out through the outlet pipe.
The beauty of this type of oiler is that the supply of oil to the cylinder is directly proportional to the speed of the engine. The faster the side shaft revolves, the faster the oiler is driven.

It was necessary to build up the cast flange on top of the cylinder as it sloped markedly towards the centre of the cylinder and there was insufficient depth of material to drill and tap for studs. A thick piece of steel was shaped and attached with JB Weld, When set, the top was milled level and tapped and drilled for two 6BA studs,
Ray

 

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