h a l f b a k e r yRecalculations place it at 0.4999.
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These quadcopters attach to the jet fighters, and raise
them
for takeoff, or land them wherever needed.
Prior art: [Voice]'s 2012 Airplane lifting hot air balloon and
my
([Pashute]'s) 2004 Lighter Than Air Landing Gear idea.
Incentive: Jet planes flying around in fear of being caught
off
guard during tense times heard from my house, the
thought of the cost of jet fuel, the waste of energy, while
remembering images of the 6 day war with the IAF's
knockout to the Syrian and Egyptian air forces.
same, but for civilian light aircraft
Robberfly_20Airport
[FlyingToaster, Feb 22 2021]
complimentary idea
Airbase_20convoy
[Voice, Feb 22 2021]
Sort of...
https://dronelife.c...s-the-best-of-both/
An RC plane with detachable quadcopter unit [neutrinos_shadow, Feb 22 2021]
Electric JATO
Electric_20JATO
[bs0u0155, Feb 23 2021]
DF-21 Carrier Killer
https://en.wikipedia.org/wiki/DF-21
[bs0u0155, Feb 23 2021]
Airplane lifting hot air balloon
Airplane_20lifting_20hot_20air_20balloon
[Voice, Feb 24 2021]
[link]
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Are you sure they're worried about the planes' ability to take
off, as opposed to being attacked while on the ground? |
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I'm sure I've read about this sort of thing somewhere before,
but I can't find it (other than the linked model, which I
hadn't seen before...); unless I came up with it
independently myself (which is definitely a possibility). |
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//take off, as opposed to being attacked while on the ground// |
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The two things are related; if the first attacking aircraft crater the
runway, remaining defending aircraft are then stuck on the
ground as sitting targets for subsequent attacks. |
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But if the attacking aircraft can blat the lumbering
quadcopters as they desperately strive for altitude, they
won't have to come back for the runway. |
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True, but even a large and slow- moving quadcopter is a smaller
and more agile target than a runway, and you can have many
more of them at a given airstrip. |
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I dunno, but I suspect they're significantly easier to destroy,
easy to target, and the survivability of any incident pretty
low. How high do you think they have to get before the
plane can launch? |
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You might be better off with an integrated VTOL like a
harrier. |
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I'd suggest that takeoff would be significantly easier than
landing, but also much more important. If the landing
site is destroyed, the craft can find somewhere else to
land like a road. With that in mind, the quadcopters only
need enough power to get the plane a few feet in the air.
The plane can provide it's own acceleration and the
quadcopters can break loose once the plane exceeds stall
speed. Having a single use rocket powered version of this
might also make sense except that the rockets would not
be a stable as quadcopters. However if maybe 3/4 of
the power was provided by rocket, and 1/4 by
quadcopter, the quadcopters could be used to
compensate for any variation in rocket power. |
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[scad mientist]; that's deserving of it's own Idea: half the
trouble with rockets is the stabilising/gimballing. A fixed
rocket with a "quadrotor nosecone" for control might just
work, and simplify (= cheaper) in the process. |
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//You might be better off with an integrated VTOL like a
harrier.// |
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The Harrier was exceptional as a piece of engineering,
but the compromises needed to make it VTOL make it a
sitting duck Vs any conventional fighter. In many ways it's
better to think of a Harrier as a really fast, big payload
attack helicopter. We'll have to see how the F35B
performs in the real world. Expensively, probably. |
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In general, protecting aircraft on the ground is already a
matter of doctrine, you go with distributed airfields, or
SAM/AA/interceptor protected airfields, or some mix.
That all falls a bit flat when you consider things like the
DF-21, if it's a carrier killer, then it can also be a theater-
airfield killer. |
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//[scad mientist]; that's deserving of it's own Idea:// |
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almost what I did with my Electric JATO idea <link>. |
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//...the quadcopters only need enough power to get the plane a few feet in the air. The
plane can provide it's own acceleration and the quadcopters can break loose once the
plane exceeds stall speed. // |
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I don't think that's the case, actually. Once the plane is moving horizontally, the
helicopter blades would lose lift on the backstroke, if they remain on a horizontal axis.
You could have them swivel forward, and effectively become propellors - some VTOL are
"tiltrotors" already. But if you then want the propellors to detach so the main body
becomes a jet -well, that's starting to look a bit awkward.
So otherwise - the plane would need to detach, then get out of stall before it hits the
deck. Seems risky. |
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//The Harrier was exceptional as a piece of engineering, but the compromises needed to make it VTOL
make it a sitting duck Vs any conventional fighter.// |
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It didn't seem to do too badly against contemporary fighters - Mirage IIIs and Daggers - in the Falkands war,
although there were other factors in its favour. I agree though that the parameters have changed over time. |
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// I don't think that's the case, actually. Once the plane is
moving horizontally, the helicopter blades would lose lift
on the backstroke, if they remain on a horizontal axis.
You could have them swivel forward, and effectively
become propellors - some VTOL are "tiltrotors" already.
But if you then want the propellers to detach so the main
body becomes a jet -well, that's starting to look a bit
awkward.
So otherwise - the plane would need to detach, then get
out of stall before it hits the deck. Seems risky. // |
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I didn't address this in my first anno because I didn't want
to scare people away with the length, and while it may
affect the design, those workarounds will not change the
overall appearance of how the system works. The tip
speed on your hobby quadcopters is pretty low, but for
something that's going to lift a fighter jet, you might have
props that look more like what you'd find on a small
plane. Those can have a tip speed around mach 0.8 (533
knots). The stall speed of a jet is somewhere near 100
knots, so you'll probably want to slow those props down
to by 100 knots. That means the retreating blade will
still be going 333 knots. So, as you said, as the air speed
increases, lift will decrease on the retreating blade. At
the same time will increase on the advancing blade, but
it likely won't compensate entirely. That loss of lift will
be compensated for partially by lift from the wings of the
airplane as the airspeed increases. If additional lift is
needed, just crank up the power on the quadcopters.
That of course means that initially, the quadcopters (with
or without rockets) need to be designed to support the
plane at something less than full power with blades
moving less than 433 knots (in this handwaving example). |
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There is a possibility that the uneven lift on the
retreating blade might cause excessive vibration of the
blades. This could be solved by allowing the blades to
flap like on a helicopter, but that increases complexity.
Since the the blades are shorter and stiffer than a
helicopter's, I'm hopping we can just strengthen the
bearings and watch out for resonant frequencies. |
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I'm not sure from the original idea, but was this
envisioned as one large quadcopter per plane or multiple
small ones? I think I'd vote for one large one mounted on
top with a total length and width barely less than the the
length and width of the plane. That unfortunately makes
it heavier with the weight of the structure needed to hold
the rotors. Several small quadcopters mounted near
wingtips and nose might work, but I'd worry especially
about the one by the nose hitting the tail after
separation. A swarm of quadcopters with longish cables
might be interesting for lifting initially, but I suspect
would become highly unstable at the higher airspeeds. |
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Just lift it high enough to recover from the stall. |
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So have the base at 20,000ft. |
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I think the Indians and Chinese are trying that in the Himalayas. |
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// It didn't seem to do too badly against contemporary
fighters - Mirage IIIs and Daggers - in the Falkands war,
although there were other factors in its favour.// |
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Plenty of other factors. Tactics, training, experience,
RADAR and missile quality & operational necessity. If
you're in a delta-winged fighter, you want the fight at
high altitude and high speed, then if things look bad,
point the nose down trade height for speed and leave the
Harriers trailing in your supersonic wake. Except the
Harriers didn't engage up at altitude and at that altitude
you're vulnerable to ship-borne missiles. Plus, you're
attacking/covering attacks on shipping, so now your delta
wing turbojet is at bingo fuel from all the flying down on
the deck, even worse, you mix it with low-level experts
over cloudy sheep country, which might as well be a
Welsh training area. Only a couple of things had to
change for the force to quickly start running out of
Harriers, even if the Argie AAA could have avoided
shooting down quite so many of their own aircraft, things
could have been a lot trickier for us. Even so, the
Harriers, and associated crew did an amazing job just
staying serviceable. |
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Just think how much mission capability we could have had
with a refreshed Sea Harrier, build on the AV8b, better
and lighter avionics, more composite structure,
composite fan & I'm sure RR could squeeze another 10%
thrust. It's not going to fare well against F15's, but we
don't fight those. Just use it as a quick helicopter that
can lob 1000lb JDAMS. |
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^Right. Is this a valid use of recursion? |
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Seems like a profligate use of fuel, to get quadcopters
with relatively low lifting capacity to carry around heavy,
fully-laden, manned fighter aircraft of dubious value. |
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Put together a fleet of unmanned drone / loyal wingman
aircraft, which are much lighter and can therefore
increase payload. |
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Add a very large lighter-than-air base dirigible platform
aircraft with massive redundancy of flotation
compartments, and guard it very well against attack (Air-
air missiles and CIWS cannon) |
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Gigantic, airborne aircraft carriers with low crew
numbers and high altitude launch capacity for the drones
it carries. Once launched, they have a loiter time of
around 36 hours, as I recall. |
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//^Right. Is this a valid use of recursion?// |
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Recursion, had to look that up briefly. I'm not sure I have
my head around it fully, but it seems somewhere between
evolution/natural selection, engineering iteration, and
the simple behavior "software" of simple animals. |
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//Seems like a profligate use of fuel, to get quadcopters
with relatively low lifting capacity to carry around heavy,
fully-laden, manned fighter aircraft of dubious value.// |
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Maybe, but I'm not sure you're seeing the advantages. It's
true that the quad/hexa/octacopters etc. have low lifting
capacities when compared to conventional aircraft and
even turbine powered helicopters, but, there is
opportunity here. Military aircraft are often limited in
terms of payload by what they can take off with in the
space available, and for nearly all of them, the take off is
a very inefficient part of the flight regime. Some sort of
strap on multi copter could be made, they scale quite
well and the mass production has advanced the flight
electronics remarkably quickly. They don't need
endurance, maybe 2 minutes of flight to hoist the aircraft
up and forward to above stall speed and you effectively
eliminate the take-off portion and increase payload. Then
the copter can fly back for a re charge. It's injecting
energy like a carrier's steam catapult, but potentially
more energy less violently. The trick would be reliable
attachment/detachment. |
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