Bill:
5 mm for 10 seconds could be a good estimate. A few weeks ago we fired a
1,9 kN motor, 160 mm OD, core burner with inhibited end planes, which had
a 5 mm phenolic liner and 6 s burntime (
http://alternative-raumfahrt.de/?p=7878 ) The liner was in a very good
shape after the test. Of course the propellant itself was the "main"
insulation. But we also used a 9 mm phenolic disc to insulate the
aluminium/graphite nozzle. This disc was exposed to the hot exhaust stream
- it is charred but will certainly endure a second firing.
Hagen
Am .02.2018, 22:07 Uhr, schrieb William Claybaugh <wclaybaugh2@xxxxxxxxx>:
Hagen:
Thank you.
So 1mm is good for 1 second, implying 10 seconds requires 10mm.
At the limit, 1mm is just barely good for 5 seconds (I’d be worried about loss of strength in the aluminum after enough heating to discolored the coating) >implying 2mm might just last for 10 seconds, maybe.
With the other data, this does seem to suggest something like 5mm as a minimum for a 10 second exposure.
Bill