More chamber pressure will nearly always provide more thrust via the nozzle’s
thrust coefficient provided there’s a de laval nozzle attached.
If the throat is only a straight hole (no convergent section or exit cone)
then it’s possible (even likely) the thrust will be slightly lower with higher
pressures as a consequence of suppressed chamber reactions (chem equilibrium),
although metal combustion (via residence time) generally is assisted with
higher chamber pressures.
Troy
From: arocket-bounce@xxxxxxxxxxxxx <arocket-bounce@xxxxxxxxxxxxx> On Behalf Of
kevin ward
Sent: Tuesday, April 18, 2023 7:51 AM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: relativity abandons small launch vehicle
Can anyone help with this equation...
More psi in combustion chamber, no matter what, results in more thrust ?
BurnSim says so...
But dad insists NASA knows best and may 1 at the throat is penultimate. Cutting
issues with "supersonic velocities, at the throat, cause problems" he pointed
out a nozzle that had Mach 1 as Max propellant mass flowing, for longer burn
time... Vs less mass at higher velocities for less burn time.
Analogy: water hose at full open creates a little thrust, put a nozzle on it
and hold on... As in a fireman's hose or a high pressure washer. You're only
going to get thrust if you tighten up the throat.
I could see a different analogy that proves me wrong as in with a boat and it's
propeller. There is a point before velocity increases, that if you apply too
much torque, you're going to cavitate. Does that apply in rockets ?
I insist that NASA is limited in acceleration due to what they're sending up;
people, equipment, O-rings that go bang, etc. And the whole point is to "attain
escape velocity as quickly as possible". Another NASA quote "controlled
explosion".
Furthermore, throats and nozzle ends are maximized per the individual rocket.
I figure they could go for, instead of steel motor casings, maybe kevlar
wrapped at 15 times psi, yielding a bunch more thrust, if they only sent a
rocket, with no purpose, other than trying 2 attain fastest object ever, other
than light.
I realize the rocket will burn up due to friction, unless properly insulated,
which isn't difficult.
If I just want to send a probe, to the kuiper belt, and wave an aerogel disc,
return and splash into the ocean.... I'll b limited by difficulty in not
destroying the aerogel, but, not NASA's fastest ever rocket, being considered
best velocity.
If you don't know, please instruct me where 2 go... B nice
Lol
Ty 4 your assistance.
P.s. Looking for team members\collaborators
Oh, pic of of M-2270. A little extra kiln coat on exterior to measure variable
temps. Inside casing is generous slathering of kiln coat (100HT). Double choked
nozzle will be additionally .25" kevlar adhered. (Playing safe at 30,000psi,
but figure capable of 50,00psi considering my imperfect epoxy to kevlar fabric
ratio.
Using air intake Jets to create gas wedge to alter vector. Passively. No gyros
or otherwise.
Additionally playing with extra metals in the propellant, i.e. rich
fuel\oxidizer mix. some of my fuel won't b onboard, rather scooped up as
accelerating, yielding less propellant mass required.
On Mon, Apr 17, 2023, 2:29 PM Henry Spencer <hspencer@xxxxxxxxxxxxx
<mailto:hspencer@xxxxxxxxxxxxx> > wrote:
On Mon, 17 Apr 2023, Uwe Klein wrote:
A corollary: if you think of the first vehicle as a pathfinder rather
than as the main operational moneymaker, it should be sized for easy
manufacturing and operation,
You learn about the target environment.
But scaling effects may turn design decisions upside down.