From (by) RocketSlinger@SBCGlobal.net (email me there please)… This is a sub-site
to main site at www.rocketslinger.com …
This web page last updated 10 March 2023
Aerostat
Maneuvering Techniques and Hiding Rockets from Zombie Radar
Abstract
This sub-page to www.ResearchGate.net (https://www.researchgate.net/publication/369143849_Aerostat_Maneuvering_Techniques_and_Hiding_Rockets_from_Zombie_Radar
) is duplicated at www.rocketslinger.com also (at http://www.rocketslinger.com/Aerostats/
). Here, we briefly add comments and
additions to what was described and discussed at https://www.researchgate.net/publication/365964188_Propulsion_Designs_Using_Novel_Nested_COPVs_and_the , with the full title being “Propulsion Designs Using Novel Nested COPVs and the
Astron Omega 1 Engine” (1st paper on associated topics), and then
also at https://www.researchgate.net/publication/366977214_Using_the_Astron_Omega_1_Engine_as_a_Compressor_and_Using_COPVs_and_Inflatables_as_Aircraft_Structural_Elements (2nd paper). This new
paper (here) then briefly discusses how aerostats (gas-bags, blimps, and
dirigibles) can be maneuvered (this is mostly internet research, but includes
new technologies which some readers may not be aware of). Finally, the bulk of this paper discusses how
one would hide rockets (missiles) from radar detection. Radar absorptive materials are barely
discussed. More-so, the focus here is
mostly on non-metallic (harder for radar to “see”) structural materials
(including, especially, for pressure vessels), fuels, and oxidizers. Much attention is paid to the “dielectric
constants” of candidate materials.
Contents
Preamble, and Bits of Boilerplate
Additions to 2nd COPVs Document
Links and Facts About Aerostats
Radar, Materials, and Dielectric Constants
Radar Absorptive Materials (RAM)
Minimal-Metal Rocket Throat and Nozzle
1st COPVs Document
The first preceding
document in this series is at https://www.researchgate.net/publication/365964188_Propulsion_Designs_Using_Novel_Nested_COPVs_and_the and
at http://www.rocketslinger.com/COPVs/ (Same
document, 2 locations)… So now, for the
remainder of this document, I can just hyper-link to 1st COPVs
Document when needed, and cut clutter.
2nd COPVs Document
The second preceding
document in this series is at https://www.researchgate.net/publication/366977214_Using_the_Astron_Omega_1_Engine_as_a_Compressor_and_Using_COPVs_and_Inflatables_as_Aircraft_Structural_Elements and
at http://www.rocketslinger.com/COPVs_2nd/ (Same
document, 2 locations)… So now, for the
remainder of this document, I can just hyper-link to 2nd COPVs Document
when needed, and cut clutter. Hopefully,
I will completely document all of my associated new ideas (and newly-found
sources) on this third go-around, but who knows, I may need to write more later…
Preamble,
and Bits of Boilerplate
As before, as with
other sub-pages of www.rocketslinger.com, the intent here is to “defensively publish” propulsion-related
(and “misc.”) ideas, to make them available to everyone “for free” (sometimes
called “throwing it into the public domain”), and to prevent “patent trolling”
of (mostly) simple, basic ideas. Accordingly,
currently-highly-implausible design ideas (usually marked as such) are
sometimes included, just in case they ever become plausible, through radical
new technology developments (often in materials sciences).
Dear Reader,
excuse me as I will often slip out of stilted formal modes of writing
here. I have no boss or bosses to please
with these “hobby” writings of mine, so I’ll do it my way! I’ll
often use a more informal style from here on in, using “I”, “we”, “you”,
etc. “We” is you and me. “You” are an engineer, manager, or other
party interested in what’s described here.
Let’s thwart the patent trolls, and get ON with it!
Additions to 2nd COPVs Document
First, before presenting the list, let me say that the list
heavily focuses on the Omega 1 engine from Astron. No, I don’t own any stock in Aston, nor do
any of my friends or relatives! I just
happen to be very impressed by this engine, and believe that it should find
many excellent applications. This engine
could easily be modified to create a most excellent gas compressor. See the 1st COPVs Document for details on the simple modifications needed to turn it into a
compressor. Use a search-string (in that
paper) of “I would take the existing
Astron Omega 1 design”…
In descending order of importance (as ranked by Yours Truly, of
course), here are the major additions or embellishments (things that I have
learned most recently) that I would like to now briefly address here:
‘1) Here
is a collection of links concerning “Jetoptera”,
which creates propulsion using jets of high-pressure air being released. And of course, I believe that the Astron
Omega 1 could make an EXCELLENT air compressor for such a propulsion source! See https://interestingengineering.com/transportation/us-startups-bladeless-vtol-can-reach-up-to-08-mach and https://interestingengineering.com/innovation/jetoptera-air-taxi-flight-bladeless-fans-vtol and https://www.linkedin.com/company/afwerx-usaf/ and https://jetoptera.com/news/completes-fourth-usaf-awarded-contract/ .
(This link is repeated from above) https://interestingengineering.com/innovation/jetoptera-air-taxi-flight-bladeless-fans-vtol
gives us some ideas about just HOW this propulsion system works. Imported from this source, see the following: “The fast-moving air is directed backward
over the air taxi's wing-shaped surface around the
ring, where it creates negative pressure — what aircraft use to lift up into
the sky. But for the J-2000, this lift-capable differential pressure is canceled
from equal negative pressure zones surrounding the ring — creating a net
low-pressure vortex in the center of the ring, which then pulls ambient air
through at a very high velocity.
The aircraft also uses a process called fluid
entrainment — vortices coalescing where cylindrical bodies of accelerated air
leave the ring, interacting with stationary ambient air surrounding it. Crucially, J-2000's concept designs can suck
up 15 times the volume of air pulled through the ring by the compressor.”
Added comments by Yours Truly: A compressor (think
Astron Omega 1!) combined with a COPV or array of COPVs for “smoothing out”
power demands would fit in here MOST excellently! Your COPV(s) could give you a boost at VTOL
takeoffs and landings, orientation changes, and at any time when you might need
a sharp boost in acceleration. At all
other times, your on-board “Omega 1”-based compressor could keep your COPV(s)
“topped off”. And these comments may
roughly apply to the below item also…
‘2) See
https://www.space.com/darpa-crane-x-plane-active-flow-control and https://www.thedrive.com/the-war-zone/darpas-new-x-plane-aims-to-maneuver-with-nothing-but-bursts-of-air ... Here, we see
that compressed air bursts (with no moving surfaces) for flight control, can be
effective. I would speculate that this
probably only applies to higher flight speeds, but I could be wrong. Quoted from there, see the following… “Aurora Flight Sciences' CRANE design, which does not yet have
an official X-plane designation or nickname, instead uses an active flow control (AFC) system to maneuver the aircraft using bursts of highly pressurized
air.”
‘3) See the 2nd COPVs Document and search for the
following search-string: “What I would now like to plainly state is
this”, and see details there. This
concerns turning bitterly cold liquid hydrogen into hydrogen gas (“gasifying”
it, while also using it as a heat sink, for pulling heat out of, for example,
being-compressed other gasses). I need
to now add the following comments also:
Before using the resulting hydrogen gas to fuel an Aston Omega 1 engine,
one would ALSO need to pressurize said hydrogen to about 300 PSI. I learned this through informal channels, and
so, do not care to try to document the source.
Contact Astron for details if needed (assuming that you’re a “real”
customer and not and idle hobbyist like me!).
Options might be obvious, but one could use a
separate Omega 1 engine driven by conventional petroleum fuel, for compressing
the hydrogen, which would in turn fuel an array of other engines. The Omega 1 only weighs about 38 pounds, so
the mass penalty is not large. Or one
could use a battery-backed electric compressor at startup, and switch the
compressor to other power later, for the start-up power for initial hydrogen
compression, similar to common gasoline-powered cars. OR one could retain enough hydrogen gas
pressure as the liquid hydrogen is gasified, to begin with! The problem shouldn’t be all that hard, but
it does need to be considered.
‘4) https://www.topgear.com/car-news/future-tech/new-1340bhp-hydrogen-powered-airspeeder-mk4-aircraft just for FYI...
It doesn’t really fit in with my recent focus on COPVs, but the Astron
Omega 1 engine (which can run on hydrogen) would sure make a good fit into this
or similar aircraft! In such cases, the
Omega 1 could be directly mechanically connected to propellers. Pressurized air and-or COPVs might only fit
as supplements here, in the style of #1 and-or #2 above…
‘5)
Again just a “general fit” here on my interests, and not COPVs
specifically. But see https://newatlas.com/aircraft/toroidal-quiet-propellers/ . Here, propeller
loops (not conventional propeller blades) generate less noise and better
efficiency in air and in water. On air drones too, then, of course. Clearly these could be used for aerostat
maneuvering (see further below).
‘6) This one is
HIGHLY relevant to the 2nd COPVs Document, where my main focus was describing how COPVs could “double up” as
structural elements of an aircraft (in the walls and ceiling of a fuselage),
and as storage banks for compressed air and-or oxygen. In that document, I envisioned rather
slower-speed (subsonic) aircraft using this trick. However, now that I’ve learned something new,
thus-stored compressed air might have another sensible use, in much
higher-speed aircraft or flight modes.
Well
then here goes; source link first. See https://theaviationgeekclub.com/heres-why-soviets-never-developed-their-own-sr-71-and-why-the-mig-25-foxbat-was-never-as-fast-as-the-blackbird/ “Here’s why Soviets never developed their own
SR-71 and why the MiG-25 Foxbat was never as fast as the Blackbird”. From this article, “(These days, most turbine
engines have hollow turbine blades, with “cooler” air from the compressor blown
through them and out tiny holes in their leading edges. The air forms a film
over the blade, insulating it from the heat of the surrounding gas. Neither the
SR-71 nor the MiG-25 had these blades. Neither had the ceramic coatings we use
today. These changes would have enabled an operating speed increase, but
probably not more than Mach 3.6 or so).”
Note
the part about slightly-hollow turbine blades, with “cooler” air flowing
through them. Well, how about MUCH
cooler air being used instead? Envision
this: Compressed and cooled air from our
COPVs is routed to the leading edge (tip) of the common spinning shaft through
the center of the compressor blades and then through the turbine blades. Somewhere between the banks of COPVs and the
final destination (the turbine blades), the compressed air is de-compressed,
and so (at that location) its temperature drops. Decompress it SOONER is good for
lighter-weight pipes or hoses carrying said pressurized air. Decompress it LATER is good for preserving
its cooling power till the last minute.
Make your engineering compromises accordingly... Also keep in mind that yes, in this design,
the cool-incoming-air pipe would have to obstruct the leading (air intake) edge
of the entire engine, at least a little bit.
Unless one somehow manages to inject the cold air between the compressor
and the turbines, which could be done, with some difficulty, and, again, with
some engine airflow obstruction, anyway.
So
this colder air now has more cooling power when it reaches the turbine blades
(after travelling some distance through the central engine axis). In this spinning axis, the cavity for the
cold air may need to find a WEE tad of extra space, for heat insulation. Maybe our rocket-launching jet aircraft
(“Cosmic Girl” style) can now kick into higher speed at the highest altitudes,
before finally launching the rocket. Or
maybe we could get wild and crazy, and have a slow-speed large “mother
aircraft” drop a “daughter aircraft”, which the “daughter aircraft” using this
cold-air-injection trick to climb higher and faster, and THEN finally the
“daughter aircraft” would launch the rocket.
Or essentially, add this air-breathing jet as the first stage on a
multi-stage rocket. Other variations may
be possible.
‘7) OK, admittedly this seriously deviates from
the topic areas of the previous two papers of mine, but it “flows from” #6
above, and stays with my general fascination with aerospace propulsion. See the “ceramic coated turbine blades”
aspect of #6 above (in the cited source).
See also https://www.mpg.de/1166083/heat-resistant-ceramic (which is mentioned again further
below). Note that this latter source may
lead to future higher-temperature turbine blades using little or no metal,
which may lead to better efficiency, less mass, and faster ability to “throttle”
the engines up and down. Less mass in
the engines means less spin-inertia (lower “angular momentum”), and so, of
course, it leads to quicker engine-speed changes.
And now I want to briefly get REALLY crazy, and suggest
another variation on ceramic jet-engine blades.
Some years ago I documented this idea at http://www.rocketslinger.com/ (root page; search for the heading “Ceramic Turbine
Blades for High-Speed Jet Engines, Mounted on the Outer Engine Wall”. I have now posted this (my root page slightly
modified) to ResearchGate, even though the ideas
there are not quite up to speed. For
reference, it is now posted to https://www.researchgate.net/publication/369142936_Using_Vertical-Rail-Mounted_Jets_for_Initial-Phase_Launch_Assistance_for_Rockets_and_Using_Outer-Wall-Mounted_Ceramic_Turbine_Blades . In summary,
even today’s ceramic materials can be kept in structural compression mode, not
structural tension mode, if they are mounted at the outer diameter (instead of
the inner diameter as they conventionally are) of a jet engine’s turbine
section. Centrifugal forces will
compress (not pull apart) the blades, in this blade-mounting mode. This, sad to say, will increase the spin
inertia (angular momentum) of the engine pretty badly. One would ALSO face the problem of, WHAT kind
of material will we use to hold these blade-bases together, at the OD (Outer
Diameter)? Such “outer rim” materials
will be FORCED to resist very high tensile forces, at high heat! Centrifugal forces will concentrate hot,
compressed gasses there also. This whole
idea is highly implausible, but… Has
been mentioned! Patent trolls are hereby
thwarted! That is, as usual, future
technology advancements may make possible, that which is impossible today.
Links and Facts About Aerostats
Aerostats maneuvering comes further
below. First, let me provide some links
and facts, for general background.
https://www.popularmechanics.com/military/aviation/a38005873/pentagon-balloons-strattolite/ is of general interest, especially from a most-recent military perspective. https://payloadspace.com/spaceryde-files-for-bankruptcy/ “Canadian ‘SpaceRyde’ Files for Bankruptcy”…. From there, “The story so far: Over the last few years, SpaceRyde has been building a system that would use a stratospheric balloon to lift the vacuum-optimized Ryder rocket above 99% of the atmosphere, release the vehicle, and ignite its engines.” Also, “The business model was simple: offer a $250,000 flat fee to launch payloads under 25 kg, then an additional $10,000 per kg up to a maximum payload mass of 150 kg and max price of $1M per launch.” (Emphasis mine.) So my comment: Yes, it looks like it could be done (balloon-hoisted rocket, rocket to orbit)… Not a new idea… No large payloads, though… https://en.wikipedia.org/wiki/Atmospheric_satellite is also a (seemingly mis-labelled) link that is highly relevant to high-altitude aerostats.
More
“FYI” on “Rockoons” (rocket balloons): https://en.wikipedia.org/wiki/Rockoon
. The biggest obstacle here is sharp limits
on the mass-size to be lifted. The
problem could be summarized as “lift aggregation”. Think of the flying-house animated movie
“Up”. Just how many balloons would it
take (how much volume of lifting gas) to lift a whole house,
and how long would the longest attaching strings then have to be? How much would those long strings then
weigh? By the time the strings were all
bunched together to carry all that lifting force, they’d have to be heavy
chains or cables! Or the lift-capturing
walls of a giant balloon would get VERY thick or heavily reinforced, to
transfer all of that lifting force, if we use one large balloon instead of
many-many small ones. Only
near-miraculous future “super-materials” will solve this problem.
See https://scialert.net/fulltext/?doi=ajt.2018.1.12 “A Brief Review of Technology and Materials for Aerostat
Application” for a good detailed document about modern fabrics for aerostats.
Misc: https://www.airships.net/helium-hydrogen-airships/ says… “Inflated with hydrogen, Hindenburg was able to
carry 21,076 lbs of payload; if the ship had been
inflated with helium it could not have made the flight at all.” https://www.thecoronawire.com/what-unmanned-aerostats-floating-drones-uavs-explained/ is of general interest, but
is badly cluttered with advertising. https://www.sciencedirect.com/science/article/abs/pii/S0360319915012689 “Research of near space
hybrid power airship with a novel method of energy storage” is definitely very
relevant. Regenerative fuel cells are
discussed here. See also https://www.researchgate.net/publication/234254664_Ultra_Long_Duration_Ballooning_Technology_Development “Ultra Long Duration
Ballooning Technology Development”.
See https://www.nasa.gov/scientific-balloons/types-of-balloons
... My notes form there: The zero-pressure balloons really DO
sometimes vent their lift gasses at the bottoms as they go up into thinner
air! The other kinds of lift balloons
are pumpkin-shaped and are called super-pressure balloons… Banana-shaped plastic strips called “gores”
are heat-sealed together, often, to create lift balloons.
See https://www.csbf.nasa.gov/balloons.html
from there: “Helium, the same gas used to
fill party balloons, is used in NASA balloons. These very large balloons can
carry a payload weighing as much as 3,600 kilograms (8,000 pounds), about the weight of three small cars.
They can fly up to 42 kilometers (26 miles) high and stay there for up to two
weeks.” (Emphasis mine.)
See
https://www.thecgo.org/benchmark/bring-back-hydrogen-lifting-gas/ …
From there, “This
means that at sea level on a 0ºC day, hydrogen provides enough buoyancy to lift
1.2031 kg per cubic meter, while helium can only lift 1.1145 kg per cubic meter
of gas. Hydrogen, then, provides about 8% more gross lift than helium
does.” …. Also…. “Helium, in other words, is around 67 times more expensive than
hydrogen.” (Emphasis mine.) This article here is a most excellent summary
of MANY reasons why hydrogen should be the preferred lifting gas of the future!
See https://spaceperspective.com/spaceship
which does use hydrogen… Also see https://spaceperspective.com/faq
where we learn that it is zero-pressure balloon… From there, “To descend the Spaceship releases a tiny
amount of gas that turns into water, so the vehicle is technically near-zero
emissions.” ….Under “safety” it
says… “It is what is technically called
a ‘zero-pressure’ balloon…” This is
intended as a passenger-rated “ride” high into the skies, and will go
operational (???) soon. Note that it has
a safety release whereby the rope-dangling gondola can detach from the balloon,
using unspecified means (probably explosive bolts or “pyrotechnic devices”, I
would bet). The gondola can then descend
by parachute. So those kinds of problems
seem to have been already solved…
Also
note the idea of a “sulfur dioxide hose into the sky” for climate manipulation
(no, I’m not about to discuss that!). See https://freakonomics.com/2011/09/finally-a-garden-hose-to-the-sky/ . The 2nd picture down from the top
is most interesting! V-shaped balloons
and a hose up into the sky! SPICE
(Stratospheric Particle Injection for Climate Engineering) in Britain was
investigating this… See http://www.spice.ac.uk/ and
http://www.spice.ac.uk/project/delivery-systems/
. Maybe the hose could bring lifting
gasses up to each balloon as the gasses inevitably slowly leak, and then we
could have rope-climbers (hose-climbers) deliver to-be-launched rockets to the
top? But we’d still have the mass
limitations due to the above-discussed “lift aggregation” problems, so this
isn’t much of a “killer app” here. Maybe
new “super-materials” will one day make this work much better! If so, we need a cool acronym for our
“Stairway to Heaven”! Something like
Aerostat-Pegged (Propelled, Powered?) Elevator (Escalator?)
– Step Ladder Into Position (Incremental Positioner?)
= APE-SLIP!!!! Let’s all go APE-SLIP, up
skyward!
OK,
back to seriousness. That’s probably
enough links and facts about aerostats.
Let’s move on.
Maneuvering Aerostats
Aerostats maneuvering, then. Some of these remarks will be totally
obvious, and some will be less so. For
starters, see https://newatlas.com/aircraft/toroidal-quiet-propellers/ (a repeat from the “Additions”
section, item #5) for the kind propellers we should use. See the “Additions”
section, item #1 for a (“Jetoptera”) alternative to
propellers. See the “Additions” section, item #2 for a (“Aurora”) possible supplement to
propellers (I suspect that it is more applicable to high speeds only).
Note that we could “drink from our hydrogen lifting gas”
for an energy source. Energy (from
burning the lift gas) could be provided using a fuel cell or an internal
combustion engine. If the latter is
used, the Astron Omega 1 engine (only 38 pounds or so!) would be a good choice,
but note that the hydrogen gas would need to be compressed first. For more notes about that (compression
needed), see the “Additions” section, item #3.
Batteries and-or compressed air (in COPVs) can be used
for energy storage. Solar collectors
could also be an energy source (all rather obvious, it seems to me). Note that compressing ambient air on-board
the aerostat (plus gondola of course), inside COPVs or other tanks, would add
mass to the assembly, and so, could be used for buoyancy control, as well as (the
compressed air could be used for) propulsion.
Gathering the hydrogen gas (for burning for power) out of
a dirigible, blimp, or super-pressure gas-bag should be trivial. For gathering it out of the bottom of a
zero-pressure balloon or “gas-bag”, it might not be totally trivial. Protrude a stiff or semi-stiff hose (pipe) a
ways up from the gondola, up into the gas-bag, since we don’t want our gas (hydrogen)
intake to get clogged up with slack gas-bag fabric. At the top of the hose, we place a large wiffle-ball-style, heavily perforated, lightweight (plastic
or fiberglass, say) ball, for hydrogen gas intake.
Also inside the perforated ball, we could place
electric-powered heater coils (chromium-nickel works well), to heat the lifting
gas, for more lift. Zero-pressure
gas-bags tend to sink at night, in the dark, and rise up when heated by
sunshine, in the day. So heater coils
could add more buoyancy control to correct for that at night, or for other uses.
That’s all that I have for that topic!
Healing the Zombies
Next, I want to move on to hiding that which an aerostat
might carry, as payload, from radar.
Much of this technology will be derived from military applications,
clearly. I don’t want to anger or offend
anyone with my own biased political or military advocacy, though. I am hoping that we can all agree that zombies
should be compassionately healed (immunized), whenever possible! So no normal-human “enemies” will be
discussed below! Our payload will be
clusters of zombie-seeking hypodermic needles, is all. So I hope that you, Dear Reader, won’t put me
into my moodiest, bluest funk, by coming knocking at my door, with a thousand
million questions, about hate and death and war! I seek ONLY to heal the zombies!
For our purposes, if or when the famous “zombie
apocalypse” comes, the zombies will likely be nearly every bit as
technologically talented and resourceful as we are, and they will NOT want to
be healed! So… Here’s where we’re headed… Our ultra-cheap hydrogen balloons will waft
our not-warheads over zombie territory, and try to evade their radars, and
we’ll vaccinate them against zombie-ism, with our… (??? Peace-heads and healing-heads
sound too funky)… NOT-warheads! They’ll be
carried on steerable-guided-finned gravity not-bombs and-or not-missiles, all
designed to be low-budget, and presenting low visibility to zombie radar.
That said, let’s go through a few links (concerning relevant
military matters) for reference, and then move on. As I’m writing this (as of early March 2023),
Chinese spy balloons over the USA are still very topical. They (balloons) can be assumed to be
relatively cheap. We don’t know for
sure, but SOME of these balloons may have been domestic (student?) weather
balloons, costing (?) what, $20 or $50 or so?
https://www.techarp.com/military/us-chinese-spy-balloon-missile/ says that the USA did spend an expensive $400,000 AIM-9X
Sidewinder missile to take it down (plus quite non-trivial operating
expenses). “The Google” will tell you
plenty more. Briefly, https://aviationweek.com/defense-space/aircraft-propulsion/hobby-clubs-missing-balloon-feared-shot-down-usaf tells us that “The descriptions of all three
unidentified objects shot down Feb. 10-12 match the shapes, altitudes and
payloads of the small pico balloons, which can
usually be purchased for $12-180 each, depending on the type.” So clearly, we might be able to bankrupt the “defensively”
over-spending zombies with hydrogen balloons, especially if the balloons carry low-cost
zombie-threatening zombie-healing non-warheads!
Include many decoys that appear (to vision and to radar) nearly
identical to the “real McCoy”, of course!
Semi-random
grab-bag of military-related links follows:
https://www.reuters.com/world/europe/ukraines-new-weapon-will-force-russian-shift-2023-02-02/ “Analysis: Ukraine's new weapon
will force a Russian shift”. This
concerns a so-called “glide bomb”, or Ground Launched Small
Diameter Bomb (GLSDB). For the launcher,
see https://www.saab.com/products/ground-launched-small-diameter-bomb-glsdb . My
summary from there, it is launched from a mobile launcher, it is ballistic,
guided by jam-proofed GPS and inertial navigation combined, and it does glide
on wings as it comes in for “final approach”.
GLSDB cost for ammo is about $40 K to $60 K (per round) according to https://en.wikipedia.org/wiki/Ground_Launched_Small_Diameter_Bomb# . We shall hope to do MUCH better (cheaper)
than that, for zombie-healing not-warheads!
From https://news.yahoo.com/iranian-made-drones-cost-little-154026964.html “Iranian-made
drones cost as little as $20,000 to make but up to $500,000 to shoot down, a growing
concern in Ukraine, report says” Also from
there, “While the Shahed-136 drones being deployed by
Russia cost as little as $20,000 to make, shooting one out of the sky can cost
between $140,000 and $500,000, The Times reported.”
OK, now that we’ve
briefly mentioned autonomous military drones; how about shifting over to
healing drones, since we want to heal the zombies? See African drones for medical
supplies delivery: https://knowledge.insead.edu/operations/africas-drone-medical-delivery-service-saves-lives-lockdown .
That’s
probably enough points to compare with where we want to go.
Radar, Materials, and Dielectric
Constants
Now, finally we get to the “meat” of
this paper. We want to hide our healing
non-warheads (and delivery vehicles) from zombies and their radars, who (zombies)
actively resist healing. In summary, the
lower a dielectric constant of a material, the less visible it is to
radar. Metals have “infinite” dielectric
constants, and reflect radar all too well (if you’re trying to hide). Any materials (almost always metals) that
conduct electricity well, will have very high
dielectric constants. That means that
our avionics (electronics) will HAVE to contain radar-reflecting metals in
circuit boards, wires, and cables…
There’s no avoiding that! But
we’ll get to that later.
Meanwhile, we’re interested
in the dielectric constants of
non-metallic structural materials, rocket fuels, and oxidizers. Keeping that in mind, let me present sources
(sources of tables) of dielectric constants, and associated facts.
Dielectric Constant
Defined: https://www.techtarget.com/whatis/definition/dielectric-constant says “The dielectric constant of a substance
or material is a measure of its ability to store electrical energy. It is an
expression of the extent to which a material holds or concentrates electric
flux. Mathematically, dielectric
constant is the ratio of a material's permittivity to the permittivity of free
space. This is why it is also known as relative permittivity.” https://www.engineeringtoolbox.com/relative-permittivity-d_1660.html says “The dielectric constant - also called the relative permittivity indicates how easily a material can
become polarized by imposition of an electric field on an insulator. Relative permittivity is the ratio of "the permittivity of a substance to the permittivity of space or vacuum". This source here has a VERY nice summary of
values of this constant, for various materials!
Ceramics are not nearly as good (low) as glass, note.
https://www.gemssensors.com/blog/blog-details/what-is-dielectric-constant-and-how-it-effects-radar
“WHAT
IS DIELECTRIC CONSTANT AND HOW IT EFFECTS RADAR” From there, “Since a higher dielectric means a higher
electric flux density, the higher the dielectric constant, the easier it is for
the microwave signal to reflect off the media.”
This source also has a short table of values (of some materials) for
this constant. https://www.toppr.com/ask/en-us/question/dielectric-constant-for-a-metal-is/
says “Permittivity of metals is very high comparable to the permittivity of
free space. So dielectric constant for
metal is infinite.”
Tables of Dielectric
Constants of Materials: http://www.ydic.co.jp/english/technology/table_E.html has fairly complete
table. https://europe.dixonvalve.com/sites/default/files/documents/dielectric-constant-values_0.pdf does, too. https://www.kabusa.com/Dilectric-Constants.pdf is VERY complete! From there, SODIUM
PERCHLORATE 5.4 is
very good. A “cheat” look-ahead to a
further-below topic is, I would much-so love to know what the dielectric
constant is for solid rocket fuel, to include this constant for “ammonium
perchlorate”, the oxidizer in such fuel, but I can’t find it (for the composite
solid fuel, or for the ammonium perchlorate).
Assuming that sodium perchlorate is similar, at least here we have SOME
possibly good news. https://www.deltacnt.com/wp-content/uploads/99-00032.pdf has another such table, and
it lists ammonium bromide at 7.1 … Again assuming that this is similar to “ammonium perchlorate”, we have some more
probably-good news. https://www.clippercontrols.com/pages/Dielectric-Constant-Values.html has a VERY complete list,
AND some very good news for
us! “Aluminum
Powder” is listed at 1.6 to 1.8 (VERY nice and low), and this is a preferred (oxidant)
ingredient in modern solid-state rocket fuel.
So we are OK there for solid-state rockets! Epoxy Resin (Cast )
at 3.6, so OK there… Wood, dry, at 2-6,
and wood, wet, at 10-30. Now the very
low constant for “Aluminum Powder” surprises
me, since, of course, aluminum is an electrically-conductive metal. Alumina (aluminum oxide) has a dielectric
constant of 9 to 11 or so (or lower, depending on some variables, such as,
whose table you look at!). I would
speculate wildly and suspect that the powdered metal form, here, has such a low
value for some strange reason related to the utterly weird surface-layer
oxidization behavior of aluminum. See https://pubs.acs.org/doi/10.1021/acsami.7b17224 , “Atomic-Scale
Insights into the Oxidation of Aluminum”.
https://www.researchgate.net/figure/Relative-dielectric-constants-of-explosives_tbl1_225662626
lists nitroglycerin at 19 so that’s not so good. This is another bit of a look-ahead “cheat”
to topics further below, but nitroglycerin used to be a sometimes-used
ingredient of solid rocket motor fuel.
See https://ntrs.nasa.gov/api/citations/19660014560/downloads/19660014560.pdf
and https://en.wikipedia.org/wiki/Solid-propellant_rocket
concerning nitroglycerin rocket fuel (and solid rocket fuel in general).
That’s
enough about dielectric constants for now.
We’ll mention such things a wee tad again further below, for specific
materials of interest.
Radar Absorptive Materials (RAM)
I don’t want to focus on this very
much, because it’s shrouded in secrecy.
So let me list a few links and facts, in the interests of listing some
ingredients that we MIGHT want to add to our (structural or fuel) materials, to
help hide them from the zombies that we so desperately want to heal! But clearly I’m no expert here, so I’ll not
go on and on. Or on and on and on and
on, either!
OK then, assorted links and facts yet again: https://assets.cambridge.org/97811070/92617/excerpt/9781107092617_excerpt.pdf (RAM = Radar Absorptive Materials) From there, “For different platforms, RAM coatings
have been developed with appropriate combination of rubber, cotton-glass, epoxy
and mica. Other possibilities are graphite fibres,
Kevlar and ferrites.” See also https://www.researchgate.net/publication/325002892_Radar_cross_section_reduction_using_perforated_dielectric_material_and_plasma_AMC_structure “Radar cross section reduction using
perforated dielectric material and plasma AMC structure” Also see https://www.key.aero/article/have-glass-making-f-16-less-observable From there, “Radar
cross section can be measured in dBm (decibels per
square meter) or more simply in square meters.”
Also “Instead, the RCS is quoted in terms of the equivalent area of a
metal sphere that would reflect back the same radar energy as the aircraft,
when viewed at the same altitude, from straight ahead. For example, the
Lockheed Martin F-22 Raptor has a frontal RCS of 0.0001-0.0002m², equivalent to
a marble-sized sphere, while the F-35A has an RCS of about 0.0015m² –
equivalent to a golf ball-sized metal sphere.”
https://en.wikipedia.org/wiki/Radar_cross-section# mentions
ferrite particles and resistive carbon added to fiberglass as RAM materials. https://en.wikipedia.org/wiki/Radiation-absorbent_material#Iron_ball_paint_absorber says that RAM ingredients can include
“iron balls”. From there, “One of the
most commonly known types of RAM is iron ball paint. It contains tiny spheres
coated with carbonyl iron or ferrite.”
This link also mentions carbon black, carbon nanotubes, and more.
Enough of this for now!
Non-Metallic Pressure Vessels
Non-metallic (made of low dielectric constant materials)
pressure vessels will be needed to store pressurized gasses, in some
rocket-engine designs (for hiding from radar, of course). If those tanks are NOT subjected to high
temperatures, as in, for example, oxygen storage, a solution is fairly
obvious. Use COPVs with plastic liners,
or with liners which are themselves made of some sort
of composites. NO metallic COPV liners
need apply for this job! Once again, “The
Google Knows All”, so I’ll say no more about that.
Another understanding (or definition) of “pressure
vessel” would encompass “combustion chambers” (in rockets here specifically),
which are tanks with holes in one or both ends.
Such “tanks” will ALWAYS have a hole at the exhaust end, leading to the
rocket nozzle. If the tanks (combustion
chambers) are for a liquid-fueled or a hybrid rocket, there will also need to
be an opening or two at the other end of the combustion chamber, for liquid or
gas entry (for an oxidizer typically, but also possibly for an oxidant,
or fuel,
for a hybrid engine known as a “reverse hybrid”). Liquid-liquid rockets MUST be summarily
dismissed here, IMHO (In My Humble Opinion), simply because designing a
low-radar-observable (minimal-metals-containing) such rocket engine is near
impossible, if not simply flat-out impossible.
So now we’ve narrowed down the pressing needs here, down
to a high-temperature, high-pressure, low-dielectric-constant pressure vessel
(combustion chamber), for a solid-state or a hybrid
rocket engine. This is NOT an easy row
to hoe! Let’s move on, to describe my
best guesses for what such a “pressure vessel” might look like. Keep in mind the Space Shuttle “Challenger”
failure, in which case high-temperature and high-pressure gasses blew out the
O-rings in the solid-state (solid-fueled) boosters. See https://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disaster for example. The
pressure will be felt at the vessel walls, whether hot gasses move, or
not. Once the hot gasses find an escape
route (for the lack of a little Dutch boy putting his fingers in the dike-hole,
if you will), all hell (rapid erosion) breaks free!
With regards to the above, https://en.wikipedia.org/wiki/Hybrid-propellant_rocket has a relevant quote.
“Pressure vessel failures – Chamber insulation failure may allow hot
combustion gases near the chamber walls leading to a ‘burn-through’ in which
the vessel ruptures.”
I’ve got my own personal (but hopefully well-informed)
opinions on what all materials might work best here. Working from the center outwards, let’s first
describe some materials that are good candidates here. For now, we’ll ignore the center, where
combustion occurs, and cover categories of that, separately, further below.
First off, consider rockwool
and rockboard (which is compressed rockwool). See https://www.rockwool.com/north-america/advice-and-inspiration/product-types/fire-safe-insulation/ , which says “ROCKWOOL insulation is made from
non-combustible fire-resistant stone wool that can withstand temperatures above
1,000°C.” Also see https://en.wikipedia.org/wiki/Mineral_wool , which says the same. Note that mineral wool and rockwool are the same thing. For mineral wool based heat barriers, see https://www.rockwool.com/north-america/products-and-applications/products/rockboard/ , which says “Fire-resistant, non-combustible product with a melting
point of approximately 2150°F (1177°C).”
Note that https://www.rockwool.com/syssiteassets/o2-rockwool/documentation/brochures/commercial/rockboard-40-60-multi-purpose-board-insulation-brochure.pdf
lists compressive strength but not tensile strength for rockboard. Tensile
strength, sad to say, is NOT going to be one of the virtues of this material!
https://www.rockwool.com/syssiteassets/o2-rockwool/documentation/brochures/commercial/rockboard-40-60-multi-purpose-board-insulation-brochure.pdf
page 5 of 6 shows a time-and-temperature graph; almost 6 hours at more than
2,000 F for stone wool to melt. “Heat
work” (time duration at temperature, often soaking up heat energy during the
melting process) is needed to do so, and a rocket (missile) flight will not be
anywhere near that long in duration. To
better understand “heat work” (not often specified in materials data sheets),
see https://ceramicartsnetwork.org/pottery-making-illustrated/pottery-making-illustrated-article/Heat-Effects-on-Glaze#
, for example, which says “Heat Work” (Heading) “The effect of heat on glaze materials can
easily be seen through the use of pyrometric cones.
While a pyrometer measures air temperature within a kiln, cones measure the
work done by heat energy. Not surprisingly, this is called heat work, a term
denoting the combined effect of time and temperature on ceramic material. For
example, prolonged heating of a ceramic body at a lower temperature may result
in the same degree of vitrification as a shorter
period at a higher temperature.”
I
can’t find a dielectric constant for rockwool or rockboard. However,
I can get close (derive a good estimate).
See https://en.wikipedia.org/wiki/Mineral_wool
, and from there, “Alumino silicate wool (ASW)” (Heading)
“Alumino silicate wool, also known as refractory ceramic fibre (RCF), consists of amorphous fibres
produced by melting a combination of aluminum oxide (Al2O3) and silicon dioxide (SiO2), usually in a weight
ratio 50:50 (see also VDI 3469 Parts 1 and 5, as well as TRGS 521).
Products made of alumino silicate wool are generally
used at application temperatures of greater than 900 °C for equipment that
operates intermittently and in critical application conditions.” Also “Kaowool
is a type of high-temperature mineral wool made from the mineral kaolin.”
Now in turn, we can find dielectric constants for the
constituent parts of “rockwool” etc. For alumino
silicate wool “dielectric constant”, https://multimedia.3m.com/mws/media/1327055O/3m-nextel-technical-reference-guide.pdf shows
“dielectric constant” at 4.7 to 6.9.
This should be tolerable. This
roughly agrees with https://accuratus.com/alumox.html ,
which shows aluminum oxide
(alumina) “dielectric constant” of 9 or so. Silicon dioxide is the other part of rockwool (roughly half), and silicon dioxide “dielectric constant” =
3.8 or so, see https://www.iue.tuwien.ac.at/phd/filipovic/node26.html .
For an alternate material, see Kaowool; https://www.yumpu.com/en/document/read/35196752/thermal-ceramics-kao-tex-1000-inproheat , which says
5.9 to 6.4 for “dielectric
constant”, which is not quite as good as Alumino
silicate wool blended with silicon dioxide, apparently.
All of the
above should describe rockwool and rockboard fairly well, for our purposes here. I select rockboard
as the first layer (past the being-combusted rocket fuel) for its ability to
insulate, and to absorb heat via “heat work”.
It won’t do a good job of holding back pressure (poor tensile strength
can be assumed), and won’t be very gas-proof (impermeable) either, I strongly
suspect. One could “lace” this material
with RAM (Radar
Absorptive Material) if
desired. Note that for RAM here, ferrite
would be a good choice for having a high melting point. https://www.metallurgyfordummies.com/ferrite-iron.html says that “In pure iron, ferrite is stable
below 910 °C (1,670 °F)”. Also note that
the outermost layers of fuel (in a solid-state or hybrid rocket motor) will
provide SOME insulation, isolation, and heat-and-pressure protection to all of
the other layers of the pressure-vessel walls, as well.
Almost as an
afterthought, see https://www.mpg.de/1166083/heat-resistant-ceramic for heat resistant ceramics that can be
drawn into fibers. These might fit in
here as well. From there, “Ceramic
fibers made of silicon, boron, nitrogen and carbon
remain tough and stable even at temperatures above 1500 degrees Celsius.” I have no idea what the dielectric constant
of this material might be, but ceramics are generally tolerable here, for us,
for this. https://www.sglcarbon.com/en/ (SGL Carbon) in Wiesbaden, Germany,
apparently plans to start producing these fibers, and they may prove to be
suitable for building high-temperature-tolerant composites, which are NOT as
brittle as ceramics usually are. Time
will tell about price and availability.
For the next
layer of material moving outwards, I chose Borosilicate Glass (AKA
“Pyrex”). This type of glass is well
known for being able (unlike other glasses) to withstand heat differentials
from one part of the glass to another.
See https://en.wikipedia.org/wiki/Borosilicate_glass , which states “Borosilicate glass melts at about 1,650 °C
(3,000 °F; 1,920 K).” Also see https://www.microwaves101.com/encyclopedias/glass-materials ,
which lists 5.1 as the dielectric constant here. (That latter source has a
handy lists of this constant for other materials as well). I chose this glass for being gas-proof
(impermeable). Ceramics could work as
well, but have
a higher dielectric constant. I locate
this glass OUTSIDE of the rockwool, because I fear
that if the glass does shatter… Note
that high pressures inside the glass compared to low pressures outside of the
glass, will put the glass into structural tension mode, which glass is NOT good
for… If the glass does shatter, large
chunks of glass blown towards the rocket throat and nozzle could obstruct the
nozzle. This would NOT be good! Blown-loose strands (fibers) of rockwool (from the rockboard)
would be more tolerable for this, so I hide the glass behind the rockwool.
Parenthetically,
for the next layer of material moving outwards, I chose the near-miracle
material (previously mentioned) of high-temperature ceramic fibers as described
at https://www.mpg.de/1166083/heat-resistant-ceramic. Many layers of this wrapped tightly around
and around the glass would keep the glass tightly bound together, even if the
glass cracks. This could be a final or
near-final layer. Sad to say, these
fibers aren’t off-the-shelf available yet, and may be very expensive. So for most if not all practical purposes…
You can safely… ignore this paragraph!
For
the next layer of material moving outwards, I chose an insulating layer,
tightly packed. As a look-ahead “cheat”
here, note that the NEXT-outer layer will be selected as a
low-dielectric-constant material which is good in structural tension mode (to
hold back internal pressure). I know of
no such material which is ALSO tolerant of truly high temperatures as well, so
compromises will have to be made, there.
But for this layer now being discussed, I chose compressible materials,
which can be tightly packed, thereby pushing from the next-outer layer, in towards
the glass. The glass will then be
“pre-stressed”, if you will, or, be put into compression mode. Now, when the rocket engine is fired up, and
internal pressures go way up, at least the pressure DIFFERENTIAL across the
glass won’t be quite so bad. We are
lessening the “tensile mode” stress on the glass, that is.
This
tightly compacted compressible layer also adds insulation and an additional “heat-work
barrier”, by the way. Constituents might
not need to be quite so tolerant of very high temperatures, and might include loose
rockwool fibers, gypsum, graphite (or other forms of
carbon), talcum, and strands of Kevlar.
Asbestos fibers would work, but are presumably too toxic. My best guess is that some majority
(predominance) of this compacted material should be the rockwool
fibers. Finally, RAM (Radar Absorptive Material) can be included as well, in this mix.
The
final (or near-final) outer layer would be there to retain pressure, in a
gas-impermeable or near-impermeable manner.
We’ll need high-tensile-strength materials there. Temperature tolerance need not be stellar. My second choice would be fiber glass. For a fiber glass “pressure vessel” provider,
we could start with, for example, https://tanksystems.com/product/frp-poly-pressure-vessels/ , “Fiberglass
Reinforcement Pressure Tanks with a Polyethylene Core”. We’d probably skip the polyethylene core,
though, and go with solid fiberglass.
My
first choice, though (for this outermost or near-outermost layer), would be
wood. Wood will be stronger in tensile
mode when it is being pulled apart lengthwise along the grain, instead of being
torn apart across the grain. So the
wooden (hollow) cylinder shape should be made of some arbitrary number of
long-with-the-grain-of-the-wood shapes.
I think that “4” is a good number here.
Each layer of these 4 shapes should be rotated 45 degrees (out of 360
degrees) with respect to neighboring layers (in a stacked manner similar to
offset bricks, one course of bricks layered with offsets to the next), and be
glued together (with wood glue) in a shape-enforcing “jig” (it scarcely may
deserve to be called a “machine tool”), and pressed down with great force,
using clamps or a hydraulic press. Pressing
the wood segments together towards the center, simultaneously with the vertical
(through-stack) glue compression, is also highly recommended. Cure the glued wood for 24 hours or more, and
kiln dry it afterwards. This is done to
drive out moisture, since moisture raises the dielectric constant of wood. Seal the dried wood assembly with gas-proof
(waterproof, moisture-proof) paint (epoxy should work well), on inside and
outside surfaces. Test for leaks, and
plug leaks with epoxy glue and-or epoxy putty.
A good source of epoxy putty is “Gapoxio”; see
http://aplusbputty.com/ .
This is AKA the “A Plus B Putty” formerly known
as Gapoxio! It
is simply fired-ceramics powder plus epoxy hardener and resin.
This
is about the only idea here that deserves a drawing, for clarity.
Figure #1
This wooden layer of the pressure vessel
should be the final (outermost) layer, most likely. It might be possible to over-wrap this in a
manner similar to over-wrapping conventional COPVs, but this would add mass, thermal
insulation (the wood would soak up more heat from the inside, and not be able
to shed it to ambient air), and expense.
Some sort of final “paint job” (camouflaged?) might be in order. And-or, field-deployed zombie-healing
personnel could be permitted to write “Heal the Zombies!”,
etc., slogans on the paintjobs, as a morale boosting method. But I think that we are done with this part!
At one end of our “pressure vessel” (AKA combustion
chamber) here, we’ll locate the rocket nozzle, and we’ll get to that soon. In the meantime, we have a bit of a “build
the ship in the bottle” problem here, in assembling the inner core (rocket fuel
to be burned) and the various layers of the non-metallic pressure vessel. Using the small “throat” at the leading edge of
the nozzle is HIGHLY implausible for “building the ship in the bottle”. We’ll need to leave the various layers
(cylinders) wide open at the other end (the not-a-warhead, zombies-healing
payload end), during assembly. The
payload end itself? Use ANY suitable
material to build this with, ignoring high temperature tolerance and the need
for impermeability.
That leaves us with designing the pressure vessel wall
between the nested cylinders, and the payload area. We need to “end-cap the cylinders”, that is. The rockboard layer
(a circular “dinner plate” for an end-cap) can just be loosely placed, to be
compressed into place next. The next
layer (borosilicate glass) can be male-threaded on the glass cylinder (bottle)
and female-threaded on a glass cap (or vice versa). Yes, female threads can be fashioned in
glass. See https://adamschittenden.com/technical/connections/threaded-connectors , which tells us that these (female threads) are called
“Ace threads”.
If by any chance glass “Ace threads” are prohibitively
expensive, female-threaded ceramic caps could be used as well. From personal experience with pottery, I know
that this would be fairly easily possible.
Cast the pottery “slip” (thick slurry of unfired ceramic material plus
water) into two separate molds, for two separate halves of the ceramic cap (two
molds are needed because of the “negative space” inside the cap). Let the two halves of the cap dry out, and
crack them out of their molds. Now you
have two half-caps made of un-fired “green-ware”. Marry the two parts together (being VERY
careful to preserve thread alignments!) while “glue”-mating them with
“slip”. Dry the assembly,
trim it as needed, and then fire it in a kiln.
Your glass-to-glass (or glass-to-ceramic) thread-mated
joint may want to (be prone to) leak.
One may wish to use a filler (between the
threads) here. Gypsum or talcum powder
(or a blend of the two) might work. Our
other choice is to NOT impermeably seal any leaky threaded joint here, possibly
let some (small amounts of) hot gasses through, and hope that our outermost
layer (wood or fiber glass) will hold fast, and not allow runaway hot-gas-flow-erosion.
Also note that there may be some “slop” (mechanical
tolerance imprecision) between the threaded glass (or
ceramic) lid, and the loosely placed circle of rockboard. Adding some compressible loose rock wool
fibers here is probably a good idea.
Outside of the glass (or ceramic) end-cap we have a layer
of compressible rock wool plus (most likely) some additives, which have been
discussed above, and deserve no further, special comments in this (end-cap)
context. Place this (compressible) layer
loosely, with a bit of extra topped-off material to be compressed in the next
step, which is to glue on (or otherwise secure) a wooden (or fiber glass)
end-cap. Attaching the not-a-warhead
(payload, out past the end-cap) should be trivial. If a wood-on-wood joint is used here (and-or
at the end-cap of the pressure vessel itself), then, at this stage of assembly,
adding wooden dowel rods to strengthen the joint(s) might be wise. In the case of a hybrid rocket engine (as
opposed to a solid-state or “monopropellant” engine), this not-a-warhead tip
compartment will also contain a COPV or COPVs containing oxygen, or other
oxidant.
So now let’s go to the other end of the pressure vessel,
where we have a constriction throat, and then a nozzle. For our purposes, I think that we should just
flat-out, rule OUT any ideas about using any kind of a swivel-able (gimballed)
nozzle. This is too complex, expensive,
and (I would bet) impossible to build without using significant amounts of
metal. Steering will need to be done by
twisting rocket fins, to be discussed later.
The throat and nozzle, I think, should be rigid, then.
Minimal-Metal Rocket Throat and Nozzle
Which then of course brings us to the throat or
constriction area. Here I am less sure of myself, so will
attempt to bloviate with more humility!
My best (OK then, first) guess for the throat area would be as follows:
The gasses here will be the hottest and highest-pressure of all, I’m pretty
sure, and will SURELY be travelling at the highest speeds. The rockboard layer
should be omitted here, going to glass as the surface which faces high-speed
(erosive-flow) hot gasses. Rockboard, I think, wouldn’t stand up to the erosion very
well. The glass layer should probably be
thickened here. Wrapping the glass in rockwool and then either wood or fiberglass in this area
makes sense to me, for the exact same reasons as were described further above,
concerning the “pressure vessel” (arguably the throat is part of the same).
For the rocket nozzle area, we could do the EXACT same… Glass, rockwool, and then wood or
fiberglass. Once again, we could
argue that this, too, is part of the “pressure vessel” although the pressures
contained will rapidly decrease as nozzle flairs out (as the hot exhausted gasses
expand). At the outermost (expanded)
nozzle area, we’d probably best retain the rock wool and wooded layers. This might be best, if for no other reason
than this: In shipment to field deployment, rough handling might happen from
time to time. We do NOT want to break
the glass (especially in the breakage-prone “neck” or “constriction throat”
area), so integral protection is wise.
Box and pad your “not-ammo” for safe shipment as well, of course! Zombies await being
healed!
More-conventional rocket nozzle composition? See https://ntrs.nasa.gov/api/citations/19660015713/downloads/19660015713.pdf , which says that “The materials used included
refractory metals, refractory-metal carbides, graphites,
ceramics , cermets, and
fiber- reinforced plastics. Three propellants with widely differing flame
temperatures and oxidation characteristics were used. The flame temperatures
were 4700°, 5600°, and 6400' F. The
engines were designed to provide a chamber pressure of 1000 pounds per square inch
and a firing duration of 30 seconds with a nozzle throat diameter of 0.289
inch.” I’m sure that “The Google Which
Knows All Things” can tell you far more about such things. The temperatures (and pressures!!!) do NOT
sound very favorable for my idea of using glass in the throat and nozzle
area! Recall from earlier that
borosilicate glass melts at 3,000 F.
Maybe the time-delay of “heat work” will save us, from the heat if not from
the pressures? I don’t know. I suspect that the wise thing to do at the
highest-stresses-parts of the throat and nozzle would be to pay the price in
terms of increased radar visibility, go a more conventional route, and use some
(limited as much as possible) metal.
The following is also HIGHLY relevant here! See https://en.wikipedia.org/wiki/Hybrid-propellant_rocket , and from there, “Hybrid rockets have
combustion chambers that are lined with the solid propellant which shields it
from the product gases. Their
nozzles are often graphite or coated in ablative materials similarly to solid
rocket motors.” (Emphasis
mine). Finally, note that SpaceX
Starship heat-shield tiles seem to be highly secretive, but are rumored to use
“Tufroc” (or similar). This might be of interest for use here (as
well as possibly in the “pressure vessel” at large, as well). Details are hard to come by. See https://ntrs.nasa.gov/citations/20190030273 . Dielectric constant of Tufroc? I
can’t find it (The Google doesn’t know! SHAME on you, supposedly all-knowing Google!). However, the following link may be
useful: https://pubs.rsc.org/en/content/articlehtml/2018/ra/c8ra01129j “Fabrication of low-density carbon-bonded
carbon fiber composites with an Hf-based coating for
high temperature applications”.
Solid-State Rockets and Fuels
Assuming that I’m
correct that solid-state monopropellants (most popularly today, powdered
aluminum and ammonium perchlorate compounded together) have low dielectric
constants (see further above here,
where this assumption is backed up), such solid state rockets are (perhaps) our
best choice, here. At this point, I’ll
simply import some links that I found useful or interesting, concerning such
rockets and fuels. https://www.sciencedirect.com/science/article/abs/pii/S0010218013003519 “Burning characteristics of ammonium perchlorate-based
composite propellant supplemented with diatomaceous earth” From there, “Kevlar fiber is an unburnable and
low-thermal-conductivity material. It is used for increasing the burning rate
of propellants by addition in small amounts [9]. This is because Kevlar fibers
protruding through the propellant surface and into the gas phase have a
“flame-holding” effect due to the shape of Kevlar. Reports of this nature have
been hardly published to date. In this
study, diatomaceous earth (DE) was used as an unburnable and
low-thermal-conductivity material.”
See https://en.wikipedia.org/wiki/Solid-propellant_rocket of course! We can NOT forget The Wiki! See https://www.sciencedirect.com/science/article/pii/S2214914717300223 “Studies on composite solid propellant with tri-modal ammonium
perchlorate containing an ultrafine fraction”.
See https://www.rocket.com/innovation/solid-rocket-motors
. See https://www.nasa.gov/returntoflight/system/system_SRB.html#
(about the Space Shuttle’s solid boosters).
To understand the burning-cavity-shapes-choices of a
solid rocket engine (and the resulting thrust-v/s-time curves), see https://www.nakka-rocketry.net/th_grain.html
or similar. In passing, let me
add a remark about something that all serious rocketry fans already know: One
disadvantage that solid-state monopropellant engines have over others is, you can NOT control (throttle) the thrust, let alone, turn
it on or off! Once lit, it stays lit
till the fuel is consumed! (Hybrid and
liquid-fueled rockets don’t share these limitations).
…And
that’s really just about all that I have for this topic!
Hybrid Rockets and Fuels
For this choice, the leading end (non-nozzle end) of our
“pressure vessel” (AKA combustion chamber) will need a hole in it, for the
oxidant to enter. PLUS it will need to
have a flow-control valve! I think that
the flow-control valve will be FORCED to contain some metal, in the valve
itself, and-or in the control mechanism.
I seriously doubt that we have any other sensible (totally metal-free)
choices here! The liquid or gas oxidizer
will oxidize a solid-state fuel which is pre-positioned around the outer rim of
the “pressure vessel” here.
It is also possible for the design to be inverted (solid
oxidizer, liquid or gas oxidant; known as a “reverse hybrid”). This is generally an inferior choice, and
won’t be discussed here. Also note that
hydrogen peroxide is an oxidizer choice, but has a high dielectric constant of
93.7. See https://cdnsciencepub.com/doi/10.1139/cjr31-023# , THE DIELECTRIC CONSTANTS OF HYDROGEN PEROXIDE-ETHER
AND HYDROGEN PEROXIDE-WATER-ETHER MIXTURES”.
So this would be a VERY poor choice for us! We are left with oxygen or nitrous
oxide. I would choose oxygen; I LAUGH
derisively at the nitrous oxide gas!
A rubber polymer called
"Thiokol" is a conventional
solid-state oxidant here. See https://www.binmaster.com/_resources/dyn/files/76563059zddc0feb2/_fn/Dielectric-Constant-Lookup-Table.pdf , where we see that
Thiokol has a dielectric constant of 7.5, which is tolerable. Other forms of (synthetic) rubber can be
used. They all seem to have low
dielectric constants as well, which is swell! All’s well with that which is swell, and doesn’t smell!
This leads us to my list of useful
or interesting
links found along the way! See https://en.wikipedia.org/wiki/Hybrid-propellant_rocket
(already previously cited here). Well OK
then, I am (perhaps prematurely) done with this topic!
Hybrid-Hybrid Rockets and Fuels
This (“Hybrid-Hybrid”) term is my invention. By this I mean a hybrid part-way in between a
hybrid and a solid-state monopropellant rocket engine. Say, for example, that we strip out a lot of
the ammonium perchlorate in the conventional monopropellant, so that it won’t
stay lit without added oxygen (as is added in the hybrid). Now, to also further partially tamp down the
burning process (tamped down for the lack of much ammonium perchlorate, when no
oxygen is incoming), we add some other (slower-burning?) only-smoldering (when
lacking added oxygen) combustibles to the solid mix. Most likely, we would retain SOME aluminum
powder. This is just me brainstorming,
now, so please excuse me if the ideas are on the crazy side. Or is this just an excuse for me to dump in
some more thoughts and links that I have gathered? Suit yourself, and believe as you will!
Now I don’t know if “flame out” is much of a problem in a
conventional hybrid, when you turn it (oxygen flow for example) off, and want
to turn it back on, or not. But some
tweaks to the solid-state fuel(s) might help with that, if they lead to
stubbornly smoldering embers in the “flame-out” (or semi-flame-out) state, when
the added (hybrid) oxygen is cut off.
And tweaking the conventional fuels here may have other benefits, such
as, for examples, costs, dielectric constants, or RAM (Radar Absorptive Materials). Or perhaps even for acting extra capacity for
insulation (or generally “heat barrier” via “heat work” as well) for shielding
the “pressure vessel” walls.
In any case, here is a grab-bag of thoughts and links for
more “wings of bat and eyes of newts” to throw into the kettle! (Glycerol has 46.5 for a dielectric constant,
so forget that one). Diesel fuel at 2.1
(dielectric constant of course) looks good!
Maybe “thicken up” this (or other) fuel oil with “pecan shell powder”;
see https://www.artmolds.com/pecan-shell-powder.html . (Or use the
pecan powder raw, as a straight-up ingredient).
Now encapsulate the (stiff) mix of oil and powder, and throw it into the
solid-state fuel mix! For encapsulating
technologies, see the drug industries in general. We won’t care about “food safe” capsules, of
course! For micro-encapsulation ideas
which just barely MIGHT be of help, see https://www.researchgate.net/publication/235924354_Microencapsulation_-_A_Novel_Approach_in_Drug_Delivery_A_Review and https://www.researchgate.net/publication/51143980_Microencapsulation_A_promising_technique_for_controlled_drug_delivery . Micro-encapsulation is no joke! See the origins of dynamite, with
nitroglycerin being “micro-encapsulated” inside the tiny little diatom shells
constituting “diatomaceous earth”, for example.
Powerful stuff, here! You might
even call it… DINO-MIGHT!!! I’m TNT, I’m dynamite! TNT, & I’ll win
the fight! Whether the avionics be AC or DC, we’ll WIN this fight! (To heal the zombies, of
course.)
In any case, ANY combustible substance MIGHT possibly be
a helpful ingredient here! Wax, wood
chips, cotton, sawdust, charcoal or other carbon, powders of plastics or
synthetic rubber or other synthetics, etc.
Or encapsulated or micro-encapsulated liquids or stiff liquids (pastes)
might work as well. You can “Google” as
well as I can, no doubt! Don’t forget that
we want a low dielectric constant.
Furthermore, for lack of much ammonium perchlorate (recall above that we stripped some
or much of it out, here), the solid-state propellant (especially if heavy on
the aluminum powder side of things) may not be of the right consistency. It may be too crumbly, too powdery, and not
solid enough. In that case, take your
diesel oil plus pecan shell powder (or other liquid plus powder), mix to the
right balance, and add it straight (not encapsulated) to the fuel mix. Picking an assortment of ingredients that
“cling to” one another, even when heated, is important! Some not-very-combustible “glue” (or binder,
or solidifier) elements may need to be added as well. Some sort of sugary (VERY sticky!) syrup
might even work, as an ingredient! Add
spices, flour, and eggs, and bake at 350 F…
Avionics, Tactics, Strategy, &
“Misc.”
The following will address how the zombie-healing
not-warheads will be deployed by avionics, at a higher level. Materials issues will need to be thrown into
the mix, from time to time. Avionics
will be central! I have no significant
visibility to costs and options in THAT particular category, since (for obvious
reasons) this is held “close to the vest” in most quarters. So the following is sometimes highly
speculative.
It WOULD be possible to deploy rather large hydrogen
balloons above zombie-held territory. In
this case, the balloons could suspend “steerable” air-breathing vessels as
described here (and above there) in this paper. Such steerable
balloon-plus-deployment-vessel-plus-payload assemblies could be interspersed as
a fraction among decoy “dummies” designed to look highly similar to those
balloons carrying the “real thing”.
Since (I think) that it is safe to assume that one can NOT design such
steerable vehicles, cheaply, to be radar-near-invisible, AND it would be
prohibitively expensive to give the “dummies” steer-ability in a flock of such
devices… The latter ability being needed to hide from the zombies, the
difference between the sheep and the goats…
AND the need to prevent the “industrial-military-complex” (or in our
case more precisely and specifically, the “zombie-healing complex”) from
succumbing to inevitable cost-inflating temptations… I think it is safe to say
that we should DROP such ideas, and focus on MUCH simpler, less-expensive
options. But in passing, note that the
“real McCoy” in such a (not-recommended-as-best, by me) case could be highly
radar reflective, while the decoys are made to LOOK the same, using the
equivalent of sheets of “chaff”. That
is, by using cheap plastics topped off with tinfoil, or similar
radar-reflective materials.
So then we are left with an assortment, perhaps, of
lower-costs “gravity not-bombs” and rocket-assisted, speedily-delivered
“healing care packages” for the zombies.
Perhaps the proper mix of hydrogen-balloon-delivered “zombie healing
care packages” will be 100% gravity-driven-only not-bombs, and ZERO rocket-assisted
“care packages”. In such a case, most of
this paper (here) is wasted, but that’s OK.
Also ponder upon this:
Radar-hiding (or partially hiding) missiles for aircraft-delivered “zombie
healing packages” may ALSO be valuable!
See, for example, “beast mode” in F-35 aircraft. See https://www.lockheedmartin.com/f35/news-and-features/raaf-flies-f35as-in-beastmode-for-the-first-time.html for
a quickly selected link. Making missiles
less radar-visible in such a case should help hide the assembly of
aircraft-plus-missiles.
It all depends on complex variables, not-a-battlefield
zombie-healing circumstances, and ever-changing developments. But if the radar force is strong with the
zombies, a mix of actively-thrusting rocket-delivered radar-seeking, fast-speed
“care packages” for zombie-healing might be best, with the rest being
simplified, steerable gravity not-bombs.
The faster radar seekers would serve as the vanguard for the slower
gravity-only not-bombs. See
radar-seeking “Wild Weasels” here, for reference: https://en.wikipedia.org/wiki/Wild_Weasel and
https://en.wikipedia.org/wiki/Anti-radiation_missile
. After the zombie radar-station
attendants are healed of their zombie viruses, and are also healed of their
zeal to “man” (“zombie”?) their radar stations, the slower gravity not-bombs
can use their zombie-seeking powers, at their leisure, to heal other local
zombies. The mix of fast, actively
powered packages, slower gravity not-bombs, and perhaps even TOTALLY harmless
decoys, will vary with circumstances.
More details, I cannot see or foretell.
I have NO crystal balls here!
Altitudes of delivered hydrogen
balloons plus “care packages” (payloads)? 20,000 feet, or 40 K, or 60
K, for targeted altitude? Again,
I don’t really know for sure. Obvious
trade-offs are: Higher altitudes are
good for being harder (more expensive) to shoot down, and for more margin for
steer-ability for seeking a wide variety of targets. Lower altitudes are better for providing less
time for the zombies to detect them duringdescent. “Spy modes” would have obvious trade-offs as
well (wider field of view from higher up; more detailed views from down
lower). Launch them in favorable-winds
circumstances, and (probably best) at night, I would think. GPS is an obviously affordable mechanism for payload-path
guidance, as is inertia guidance also.
If secure communications links can be provided, remote manual path-control
(steering) is also an obvious option.
These latter comments of mine (in my vision where we give the balloons
themselves little if any steering or maneuvering abilities) apply more so to
the “gondola” payloads than they do to the balloon-included assembly.
“Networked” or “distributed” intelligence here is a good
option. Launch these zombie-healing
delivery vehicles plus payloads in groups of (?) 10, 20, 30 or more, spaced out
a bit from each other. Have them
communicate with each other via short-range radio. If radio is too easily detected by the
zombies, MAYBE use tight-band, highly directed, non-snoopable
communications lasers instead! It all
depends, as usual! But such “networked
intelligence” can be highly useful! A
simple “polling mode” among all members, of “are you still there?” would be
enough to detect that the zombies have started to KILL parts of your networked
flock! Another (complementary) choice is
to have the “gondola” detect being suddenly dropped, as in,
the zombies have shot the balloon. At
that point, payloads are released, and seek their targets! This is much like a bunch of angry hornets
(or other hive-based stinging insects) detecting that the hive has been
violated! What is most affordable and-or
practical here? I have no idea!
“Hydrogen pollution” may be a concern here. See https://www.theguardian.com/environment/2022/jun/17/pollutionwatch-hydrogen-power-climate-leaks# , “Pollutionwatch, Greenhouse gas emissions, For hydrogen power to be a climate solution, leaks must be
curbed”. To guard against this, at some
(probably rather small) cost, a safeguard can be implemented. As the payload (“gondola”) detaches from the
balloon, a small gun shoots an incendiary load such as white phosphorus or “tracer
bullets” at the balloon. See https://en.wikipedia.org/wiki/Tracer_ammunition and
https://en.wikipedia.org/wiki/White_phosphorus_munitions
. These will burn up the balloon’s
hydrogen. Such balloon-burners can be
fired by cheap 3D-printed short-lived (“one-shot”) plastic guns, with low
dielectric constants for the constituent gun materials. We do NOT care about gun durability
here! Such a gun would be triggered A)
when the payload detaches from the balloon, or B) when the whole assembly
strays too far from the target area. In
case “B”, the payload itself might also best be destroyed. For an analogy, see out-of-range rocket
self-destruction. See https://psemc.com/solutions/flight-termination/# , “What
Is A Flight Termination System?” “Strayed out of range” can be detected via GPS,
and-or by other means.
Our zombie-healing assemblies (not-missiles and-or “dumb”
gravity not-bombs) will HAVE to contain SOME metal! Wires, circuit boards, flow-control valves
(in the case of hybrid or hybrid-hybrid
rocket engines), steering-fin-controlling devices (actuators), and (EXTREMELY
likely) the highest-stresses areas around the rocket engine “throat” and the
smaller-diameter base of the rocket engine, will be FORCED to contain
highly-radar-visible metals! These areas
will deserve extra precautions, in terms of being shielded by RAM, as best as is
possible. This is analogous to how
“Mother Nature” (by “design” of evolution… Or by God; I am NOT itching to get
into fights about THAT!) specially shields (in us humans
as well as other vertebrates) our vitally essential brains and spinal nerves in
solid bones, while the rest of our bodies are more-affordable “endoskeletons”
instead of “exoskeletons”.
Steering-fins control (actuators) details are beyond my
scope here. The only details I have to
add are, the flight profiles of gravity not-bombs may
very well best be to have the fins LEAD, closer to earth, as the assembly
descends. This allows more
flight-direction and flight-duration control, as the body of the assembly
serves as a bit of a controlling “lifting body”. The falling assembly “swims” through the air,
that is. It “falls with style”! Also note, the assembly (if instead rocket-propelled,
not “falling with style” not-a-bomb) should be hung (as a “gondola”) nozzle end
down, with the nozzle pointed down to avoid collecting any rain, during balloon
flight. Large fins and the right “mass
balance” will force orientation-correction before the rocket motor is fired up. This type of assembly will want to accelerate
downwards, clearly, I think.
Flight-path control MIGHT possibly be partially or wholly
controlled by on-board compressed-air storage (such air being stored in COPVs
NOT containing metal, with liners of plastic or composites) and “technologies”
involving these things,
items #1 and-or #2.
Path control (for both the gravity not-bombs and the downward-powered-flight
not-missiles) should be path-randomized, to evade zombie counter-fire, if at
all possible and affordable. The zombies
will fight dirty! We must evade! Make their jobs of clinging desperately to
their un-cured zombieness as difficult as is
possible! Also not that in the cases of hybrid or hybrid-hybrid
rocket engines, the engines could also be throttled up and down, and shut off
and started back up, to create more evasive maneuvers. Periodically shutting the rocket engine down
would ALSO provide cooling-off time periods, to reduce the probability of
over-heating and-or total assembly failure.
Dear Reader, I most certainly do NOT mean to insult your
intelligence! But I do also feel
compelled (in the name of thoroughness) to point out what may be obvious. Our payload-delivery assemblies will spend a
long time balloon-suspended in the air, visible to zombie radar, while
incorporated RAM (Radar
Absorptive Materials) will be useful, whether such materials are
high-temperature tolerant, or not. It is
only after a rocket motor (if applicable) is fired up, that temperature
tolerance of such RAM materials will matter at all. And the time-duration of this powered flight
phase will be very brief! So design
accordingly! Certain RAM materials NOT being
high-temperature tolerant may not matter very much.
Now I have no data or links to back me up, here, but I’m
convinced that avionics (computer hardware and software, sensors, actuators,
and communication links) will comprise the bulk of the costs here, especially
if we insist on efficacy (and I, for one, think that we should… We should select targets as intelligently as
is at all possible). On these things, I
have little expertise, and no further comments.
Concerning zombie-sensors, I have flat-out ZERO data, and seriously
doubt whether ANYONE has such knowledge!
Such matters will almost definitely await the added urgency that will
arise when the (perhaps purely hypothetical) hidden zombies chose to appear to
us, and-or the much-dreaded “zombie apocalypse” begins. If or when this happens…
I reserve the right to say “I told you so”!
(If it does NOT happen, then… Never mind;
forget what I said! Did I ever say
THAT?).
Concluding
Remarks
This
is on an almost purely personal note.
I’ve actually wrestled with my conscience about writing and publishing
this paper. Few of us like war,
especially those who have seen it up close and personal, or, at the very least,
have studied war history and have well-functioning imaginations, plus
benevolence. None of what I have
reported is secret (it’s from publically published links from the internet, known
engineering facts, and maybe a tiny bit from my imagination). If the zombies want to turn these ideas
around and use them on US, the normal human beings, then they’ll be able to do
so without this paper, and without my help, anyway. So I’m OK with all of that. If that will come to pass, I trust that the
normal humans will have superior cooperation amongst themselves, a superior
economy, and superior avionics. Let’s go
heal some zombies!
Back to main site at www.rocketslinger.com
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