Reply To: Porta's Derivation of Lempor Theory

[Martin Johnson]

Hello Chris,
Hyperboloids – an interesting concept. As to manufacture- for chimney or nozzles the internal form woud these days be cut on a CNC lathe, feed in the co-ordinates and there you are. For those of us working without CNC you carefully mark out or otherwise cut a form tool of the correct form and use that in a lathe.

I take it you also mean the nozzles would be arranged pointing in a “helix”. Producing a nozzle block with seatings for such nozzles is also reasonably easy to manufacture – really no more difficult than the splaying out nozzles of the S160 exhaust shown on this site.

Benefits – they would be quite subtle I think, but you do get more path length of the steam jet for a given height before entering the mixing chamber; so it helps to solve that eternal fight against vertical height to keep within loading gauge.

Martin