20+14.7= 34.7 PSIA so you can achieve sonic flow at the throat and
supersonic in the divergent portion of the nozzle.
K
On Mon, Feb 8, 2021 at 1:47 PM Paul Mueller <paul.mueller.iii@xxxxxxxxx>
wrote:
Yes, 20 psig chamber pressure at sea level.
After I wrote that I hadn't seen mach diamonds in a hybrid I recalled one
that we made with sugar fuel (like rock candy but with no oxidizer)
produced a clear flame with distinct mach diamonds. My bad...I should have
said HTPB hybrids
On Sun, Jan 24, 2021 at 7:40 PM roxanna Mason <rocketmaster.ken@xxxxxxxxx>
wrote:
But if your 20 psi is in gauge then Pc is 34.7 PSIA which is greater than
2/1 pressure ratio, sufficient for choked flow and shock diamonds which
aren't always visible if the plume is obscured with smoke or luminous,etc.
K
On Sun, Jan 24, 2021 at 6:34 PM troy@xxxxxxxxxxxxxxxxxxxxx <
troy@xxxxxxxxxxxxxxxxxxxxx> wrote:
You're right that you certainly don't need mach diamonds to verify
choked or even efficient flow. Saying that, I've seen plenty of nitrous
hybrids produce mach diamonds using a variety of fuels ie. Wax, PVC and
some others on a small (hobby) scale and HTPB & PE on larger scales.
Troy
Sent from my phone
-------- Original message --------
From: Paul Mueller <paul.mueller.iii@xxxxxxxxx>
Date: Mon, 25 Jan 2021, 12:53 pm
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: Math and specifics of hybrid nitrous.
Please correct me if I'm wrong but I think you can have choked flow
through the nozzle if the chamber pressure is only about 20 psig (at sea
level). My experience with hybrid motors is that the flame is opaque and I
can't recall ever seeing mach diamonds (in motors that had chamber
pressures around 300-500 psig).
Paul
On Thu, Jan 21, 2021 at 8:17 PM Evan Daniel <evanbd@xxxxxxxxx> wrote:
By far the simplest way to do this, in my opinion, is a relief valve
on your run tank. If you go this route, you'll also want a dump valve,
since your tank won't depressurize on its own.
Evan Daniel
On Thu, Jan 21, 2021 at 10:44 AM Edward Wranosky <edwardcw@xxxxxxxxx>
wrote:
temperature regulate your nitrous oxide. Remove ALL the variables you can.
That is from Todd Moore - owner of Sky Ripper Systems.
Another piece of advice is to go the route that Mark (MCS) started and
numbers to get an instinct for what's likely to work. Sorry I cannot find
Edward
On Wed, Jan 20, 2021 at 3:08 PM <mark.spiegl@xxxxxxxxx> wrote:
Jack Hanna wrote:
So, how to math?
Here's an N2O hybrid spread sheet if you want to play around with
the original to properly credit the author:
http://www.spiegl.org/rocket02/HDASv1.6.xls
--MCS