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
On Thu, Feb 1, 2018 at 1:56 PM Hagen Hübner <hagen.huebner@xxxxxx> wrote:
Bill:
Some (quite restricted) "user data": A 1 mm Phenolic-Liner (Hp 2061) in a
38 mm OD casing will withstand a 1 second burn of APCP (no Al or other
metals added) in a free standing BATES-grain configuration without any
problems. It will be coked after a 5 second burn with the same propellant
in an end-burner configutation but will still save the aluminum-casing
(wall thickness 2 mm) from a burn-through (just some discoloration of the
anodic coating). I can provide photos if desired.
Hagen
Troy:
Let me add that given 0.8 mm and a (conservative) 1.2 second burn, it
follows that this liner was good for about 0.66 mm per second, implying a
need for 6.66 mm for a 10 second burn.
With enough similar data it will be possible to estimate a number, with
variance, that at the low end allows for a (probably) safe flight.
Bill