engine construction

Reading about the conventional bundled tube regenerative cooling chamber
is made, it sounds laborious, and with so many little parts to get wrong.

I was thinking, what about shells with CNC milled passages between oven
brazed together? So many fewer parts and so much less manual labor.

I also read they had oxidation problem brazing one engine. Not a
problem if done in an oxygen free atmosphere.

Henry Spencer wrote

In article ,
Penguinista wrote:
I was thinking, what about shells with CNC milled passages between oven
brazed together? So many fewer parts and so much less manual labor.

Modern practice for chamber and upper nozzle tends to be to machine the
inner wall and passages out of a copper alloy (for good heat conduction),
and then electrodeposit a nickel outer wall (for strength). This handles
high pressure, and the accompanying high heat flux, rather better. Only
the lower nozzles are usually tube-wall now.

Cool! I used to do copper/nickel electroforming for waveguides and the like.
Got pretty good at it. Maybe I'll try a small engine. Are there any designs
available?

Any thoughts on embedding carbon fibres in the nickel for extra strength?




--
Peter Fairbrother

In article ,
Peter Fairbrother wrote:
Modern practice for chamber and upper nozzle tends to be to machine the
inner wall and passages out of a copper alloy (for good heat conduction),
and then electrodeposit a nickel outer wall (for strength)...

Cool! I used to do copper/nickel electroforming for waveguides and the like.
Got pretty good at it. Maybe I'll try a small engine. Are there any designs
available?

In the sense of full engineering drawings, no, not that I'm aware of.
Drawings for a professional-rocketry engine wouldn't be a good choice for
amateur production in any case, because the calculations would be done
around alloys you'd have trouble getting (e.g., copper with small amounts
of zirconium and silver).

Any thoughts on embedding carbon fibres in the nickel for extra strength?

Potentially interesting, if you could get the right bond strength between
the nickel and the fibers (not too weak, not too strong -- you want the
bond to fail before the fiber fails).

Also interesting, although not so simple, would be an all-composite outer
wall. The outer wall shouldn't get particularly hot.
--
MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer
first ground-station pass 1651, all nominal! |