Anthony J. Cesaroni
President/CEO
Cesaroni Technology/Cesaroni Aerospace
<http://www.cesaronitech.com/> http://www.cesaronitech.com/
(941) 360-3100 x101 Sarasota
(905) 887-2370 x222 Toronto
From: arocket-bounce@xxxxxxxxxxxxx <arocket-bounce@xxxxxxxxxxxxx> On Behalf Of
William Claybaugh
Sent: Friday, January 18, 2019 4:49 PM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: turboramjets etc. (was Re: What OSHA?)
Monroe:
Long ago, folks at then Lewis Research Center told me that subsonic combustion
ramjets had the lowest specific fuel consumption of any jet.
Is that incorrect?
Bill
On Fri, Jan 18, 2019 at 2:10 PM Monroe L. King Jr. <monroe@xxxxxxxxxxxxxxxxxx
<mailto:monroe@xxxxxxxxxxxxxxxxxx> > wrote:
Ramjets use a lot of fuel. They operate in a narrow altitude band
without lots of complications. Scramjets are still pie in the sky. (They
don't work in the real world) our materials are still too flimsy or
heavy.
The SR 71 was a flying fuel tank. (Literally) it's about as close as you
can get and that's Mach 3.2 you need Mach 25 to make orbit you can't
carry enough rocket fuel to make up the difference.
There are plenty of Ramjets in use still today they have their uses.
Ramjets are old news and they have been put to use where they make
sense.
Without some serious innovation rockets are the best way to space.
Monroe
-------- Original Message --------
Subject: [AR] Re: turboramjets etc. (was Re: What OSHA?)
From: Eivind Liland <spookysys@xxxxxxxxx <mailto:spookysys@xxxxxxxxx> >
Date: Fri, January 18, 2019 1:14 am
To: "arocket@xxxxxxxxxxxxx <mailto:arocket@xxxxxxxxxxxxx> "
<arocket@xxxxxxxxxxxxx <mailto:arocket@xxxxxxxxxxxxx> >
Noob questiom: Why aren't linear ram/scram engines popular? You'd be able to
change shapes much more easily than with radial ones
________________________________
From: arocket-bounce@xxxxxxxxxxxxx <mailto:arocket-bounce@xxxxxxxxxxxxx>
<arocket-bounce@xxxxxxxxxxxxx <mailto:arocket-bounce@xxxxxxxxxxxxx> > on
behalf of Monroe L. King Jr. <monroe@xxxxxxxxxxxxxxxxxx
<mailto:monroe@xxxxxxxxxxxxxxxxxx> >
Sent: Friday, January 18, 2019 5:34:57 AM
To: arocket@xxxxxxxxxxxxx <mailto:arocket@xxxxxxxxxxxxx>
Subject: [AR] Re: turboramjets etc. (was Re: What OSHA?)
"Yes, you're limited to a narrow range of cruising speed, but that
doesn't
necessarily eliminate their usefulness for gaining enough altitude"
Ramjets don't like altitude changes simple ones can really only be tuned
well for specific and narrow altitude range.
There is your real problem.
Monroe
-------- Original Message --------
Subject: [AR] Re: turboramjets etc. (was Re: What OSHA?)
From: "Troy Prideaux" <troy@xxxxxxxxxxxxxxxxxxxxx
<mailto:troy@xxxxxxxxxxxxxxxxxxxxx> >
Date: Thu, January 17, 2019 7:23 pm
To: <arocket@xxxxxxxxxxxxx <mailto:arocket@xxxxxxxxxxxxx> >
transition,Add the addition of a "rocket mode" into that chamber and wouldn'tsystem?
that be reasonable conceptual starting point for a spaceplane propulsion
For small values of "reasonable". :-)
Some modern tactical missiles are rocket/ramjet combos, running as rockets
briefly to get up to ramjet speed, and then cruising as ramjets. They
generally find it necessary to eject a nozzle insert during the
because in rocket mode they want a much smaller throat.going
Which suggests that any rocket mode added to an afterburner/ramjet is
to perform poorly.
It's not a perfect corollary though with sea level rockets liking large
pressure ratios for reasonable performance whereas high altitude rockets
prefer larger expansion ratios.
(Just adding a separate rocket engine could well be
preferable, considering that the T/W of a good pump-fed rocket isliterally an
order of magnitude higher than most airbreathing engines.)
Well, on the flip side of that coin: the specific impulse of some air
breathing engines can be an order of magnitude higher than rocket engines
too - particularly at the altitudes they operate at.
bypass the
If your goal is suborbital spaceflight, almost certainly you want to
ramjet mode and just go straight to rockets as soon as you're lined up forrocket
ascent. Depending on your exact concept, there might be a turbojet phase
before that, and/or a turbojet phase after reentry, but if you've got
propulsion anyway, a ramjet mode almost certainly doesn't pay for itself--
too much complexity and mass for (by rocket
Ramjets don't need to be particularly burdensome in terms of mass if you can
keep them as simple as possible eg. no variable diffusers etc. & utilise
most of the elements for the other propulsion stages - well, in naïve theory
:) Yes, you're limited to a narrow range of cruising speed, but that doesn't
necessarily eliminate their usefulness for gaining enough altitude for your
low pressure ratio rocket stage to kick in.
Troy