Lots of ramjets are not radial most of the ones I've seen are actually
more square.
I know a guy that has a patent on some kind of horizontal launch schema.
I ran the numbers over and over again using just the rocket equation.
Make sure you get the weight for the fuel and tanks close. (Don't Cheat)
I don't care about the shape of the engine none of that theory was
needed to do the math.
Try any number of methods you like.
Do this before you spend time designing any ramjet/ramrocket/turbine
combination.
Monroe
-------- Original Message --------
Subject: [AR] Re: turboramjets etc. (was Re: What OSHA?)
From: Eivind Liland <spookysys@xxxxxxxxx>
Date: Sat, January 19, 2019 3:21 am
To: arocket@xxxxxxxxxxxxx
Ramjets use a lot of fuel. They operate in a narrow altitude band
without lots of complications.
The point of my question remaining: Wouldn't you be able to change shape
much more easily, thus reducing these complications, with a linear
(extruded 2d shape) rather than a radial (axi-symmetric) type of engine?
With no rotor, it would seem you are not limited to a radial shape.
Den fre. 18. jan. 2019 kl. 22:10 skrev Monroe L. King Jr. <
monroe@xxxxxxxxxxxxxxxxxx>:
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 --------able to change shapes much more easily than with radial ones
Subject: [AR] Re: turboramjets etc. (was Re: What OSHA?)
From: Eivind Liland <spookysys@xxxxxxxxx>
Date: Fri, January 18, 2019 1:14 am
To: "arocket@xxxxxxxxxxxxx" <arocket@xxxxxxxxxxxxx>
Noob questiom: Why aren't linear ram/scram engines popular? You'd be
________________________________behalf of Monroe L. King Jr. <monroe@xxxxxxxxxxxxxxxxxx>
From: arocket-bounce@xxxxxxxxxxxxx <arocket-bounce@xxxxxxxxxxxxx> on
Sent: Friday, January 18, 2019 5:34:57 AMpropulsion
To: 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>
Date: Thu, January 17, 2019 7:23 pm
To: <arocket@xxxxxxxxxxxxx>
Add the addition of a "rocket mode" into that chamber and wouldn't
that be reasonable conceptual starting point for a spaceplane
rocketssystem?
For small values of "reasonable". :-)
Some modern tactical missiles are rocket/ramjet combos, running as
Theybriefly to get up to ramjet speed, and then cruising as ramjets.
rocketsgenerally find it necessary to eject a nozzle insert during thetransition,
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
enginesprefer 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
up fortoo - 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
phaseascent. Depending on your exact concept, there might be a turbojet
itselfbefore that, and/or a turbojet phase after reentry, but if you've gotrocket
propulsion anyway, a ramjet mode almost certainly doesn't pay for
you can--
too much complexity and mass for (by rocket
Ramjets don't need to be particularly burdensome in terms of mass if
utilisekeep them as simple as possible eg. no variable diffusers etc. &
theorymost of the elements for the other propulsion stages - well, in naïve
doesn't:) Yes, you're limited to a narrow range of cruising speed, but that
yournecessarily eliminate their usefulness for gaining enough altitude for
low pressure ratio rocket stage to kick in.
Troy
