Epoxy melts at surprisingly low temperature. Try phenolic.
Peter Fairbrother
On 22/04/2021 08:16, Hagen Hübner wrote:
Hello everyone,
a few days ago we (Forschungsgemeinschaft Alternative Raumfahrt - FAR e.V.) tested an O-motor with a nitrate-based fuel. The part of the nozzle near the combustion chamber was made of graphite and withstood the high temperatures and the abrasive exhaust without any problems. The nozzle extension - for weight reasons made of carbon fiber reinforced epoxy resin (tempered, but otherwise standard resin), material thickness 3 - 7 mm - however, failed after about one second of burning time (see attached photos).
Question(s): What can be improved to prevent the extension from burning through in the future?Is there any chance at all chance to make a weight-saving nozzle extension made of composite, designed for a burn time of 5 - 10 seconds? Which more temperature-resistant resin should I use? Which reinforcing fibers are (more) useful? Do basalt fibers have a significant advantage over carbon fibers?
Regards,
Hagen