I'm afraid there will be no epoxy resin durable enough to withstand
these tempereatures. Most epoxy resins decompose around 120 °c with
every few withstanding 200-250 °C. One could use phenolic resins I
suppose, at least Aerotech has successfully flown their O motor
recentlyx without significat nozzel erosion...
Other than that: with an O motor, is 50g-100g more weight at the nozzle
an issue ;) ?
Cheers,
Tom
Am 2021-04-22 09:16, schrieb Hagen Hübner:
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