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U2 Replacement?

05/11/2009 5:46 PM

No i'm not talking about the band, but the spy plane.

I know the Blackbird more or less replaced the U2. And of course the new spy sattellites ahve more or less replaced the Blackbird.

But i am looking for a plane that had similar slope ratios that the U2 had. it was like a glider.

I am in other words looing for a glider that operates well at high altitudes.


Joe

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Guru
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#1

Re: U2 Replacement?

05/11/2009 7:47 PM
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#2
In reply to #1

Re: U2 Replacement?

05/11/2009 10:20 PM

That does seem like a decent glider. I wonder how it performs at HIGH altitude?

2000 feet for what we do is not even 2% of the altitudes we are experimenting in.

We are looking at 110 to 120 thousand feet. Looks like this shot we took from 102,000 feet.

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#22
In reply to #2

Re: U2 Replacement?

05/13/2009 7:59 PM

I think I see my house!

Yup, Thats it right over there!

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#24
In reply to #22

Re: U2 Replacement?

05/14/2009 7:34 AM

Not just your head in the clouds, then?

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Guru

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#3

Ground Effect Flight

05/12/2009 1:04 AM

For your "spy plane": Make it "density variable" and soar it at "neutral buoyancy." Use the lifting gas as propulsion fuel for the minimal impulse required to alter vehicle ground track.

Hybrid the concepts of airfoils and lifting gasses. Watch how a bird controls ground track while "dynamically soaring."

But if you wish to do something constructive; consider a really unconventional fast and efficient transport aircraft - flown in a shaped tube. Use ground effect to enhance lift, pull your power off induction cables through the wing-lets, and power it with electro-fans where the fans reduce the air density directly in front of the vehicle reducing the aerodynamic drag. In short, all the advantages of mag-lev and high altitude flight but at a huge infrastructure and vehicle cost savings. No more spending energy hauling around flammable fuels and flying in an absolutely stable flight environment.

For spanning large bodies of water make the tubes variably/neutrally buoyant at depth. Perhaps to traverse the Bearing Straight, the Gulf of Mexico, or about any large body of water.

Make the tubes in modular two piece sections. A base and a top. Lay the base, lay the induction cables and put the top on. When building across bodies of water close off the completed section, add on some length, close off that length, pump out the water, move the water barrier up to the next working point.

High speed rail is an ancient concept; and it is anything but cheap. Why waste all that steel. Its slow and old. High speed rail is an oxymoron.

Erase the small control surfaces shown to control pitch. Because the flight environment would be so stable, pitch and roll could be controlled by very slight variations to enter of mass. Yaw would be inherently controlled by the variations in power supplied by the electro-fans as the induced power is altered by slight variations in the relative position of the inductors to the induction cables.

It may be a wild idea - but hey - it sure was fun dreaming up.

Gavilan

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#4
In reply to #3

Re: Ground Effect Flight

05/12/2009 3:02 AM

I was trying to follow all along your description and honestly was getting lost for sure. Then i seen the ketch,,

Hey! It's a klingon bird of Prey!


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Guru

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#5
In reply to #4

Re: Ground Effect Flight

05/12/2009 12:19 PM

I have never understood why sci-fi spacecraft look like they are designed for aerodynamic flight; but hey - it looks good to me. Make the body a "lifting body" and put the inductive pickups in the wingtips. Slide it in the guide-way and close the switch.

I love your 102,000 ft picture; care to comment on how you got there?

Gavilan

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#6
In reply to #5

Re: Ground Effect Flight

05/12/2009 12:45 PM

http://www.qsl.net/wb9sbd/educators.html

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Guru

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#7
In reply to #6

RE:U2 Replacement - Airborne Technical Intelligence Platforms

05/12/2009 10:25 PM

As I suspected. Ballooning is certainly not a new concept in technical intelligence platforms but that doesn't make them any less useful, especially when considering their stealthy nature, cost, and deploy-ability.

Perhaps the folks in that business have/will hybrid the concepts of airfoils and lifting gasses in order to give the craft the capability to adjust ground track.

I have given that concept considerable thought over the years but for different applications.

Gavilan

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#32
In reply to #6

Re: Ground Effect Flight

05/20/2009 9:06 AM

Cool. I'm going to have to really check out your site when I get a chance. This looks like something that would be good for my science classes!

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#9
In reply to #5

Re: Ground Effect Flight

05/13/2009 2:06 AM

"I have never understood why sci-fi spacecraft look like they are designed for aerodynamic flight,"

And they usaually have them make sounds in the vacuum of space.

Probably cheap stability rather than aerodynamics.

However, some shows had ships do atmospheric travel.

Some shows have ball shaped ships. Whack it and watch them spin. They would have serious inertial stability technology to keep that from happening.

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#20
In reply to #5

Re: Ground Effect Flight

05/13/2009 4:57 PM

I suspect that they have developed from the early comics, where the space-craft was assumed to fly up to the edge of the atmosphere and convert to rocket propulsion thereafter. Like a powered shuttle. The difficulty is compatibility between efficient flying surfaces and the materials science for ultra-high-speed entry to the atmosphere (both mechanical strength and surface heating). I blame Arthur Clarke for conditioning our thinking. (Plus, as automotive manufacturers discovered long before they started making shapes that were genuinely efficient aerodynamically, people's perception of shapes means that "apparently aerodynimic" coincides with "attractive".

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#8

Re: U2 Replacement?

05/13/2009 1:10 AM

surface man......at those altitudes....it's all about surface.............

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Associate

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#10

Re: U2 Replacement?

05/13/2009 5:33 AM

This thread seems to have wandered off topic. To return a moment, it is interesting that they bring out the old manned spy planes from time to time, as satellites have one huge disadvantage - the other side know exactly when they will pass over, so can do what they like in between passes. I believe the TR1 (upgraded U2) was brought out of mothballs to look at N. Korea fairly recently.

It is possible the US has some manned replacement but far more likely they now rely on UAVs - whether small and low (which we know about) or big and high, which we do not.

You may like to take a look at Qinetiq's Zephyr http://www.qinetiq.com/home/products/zephyr.html

the world's highest and longest flying UAV (that we know about). But well short of your requirements at 58,355 feet. (Feet? What are they? I was taught metric units at school in the UK in the 1950s.)

(BTW That Qinetiq site will probably interest engineers on every page)

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#11
In reply to #10

Re: U2 Replacement?

05/13/2009 6:45 AM

I don't think the TR-1 did come out of service. I know they were flying them as late as '94 when I left the service. I was in the Army and worked on an ASARS systems that worked in conjunction with the Airforce to do Radar Imagery. They would provide the plane we had the ground station.

Amazing plane, only got to see one in person once. During the first gulf war one plane (not a radar plane but a photo plane) had to make an emergency landing in Riyadh where we were stationed and we got to go and do a quick walk around. As it was an unexpected landing they did not have the pogos on hand to prop up the wings so it was tipped to one side with the wing tip resting on a bale of hay. It struck me as odd as such an advanced piece of engineering would need hay to hold itself up as well as where did they get the hay in the desert in Saudi Arabia. :)

Shawn

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#12
In reply to #11

Re: U2 Replacement?

05/13/2009 7:41 AM

Here in East Anglia UK we sometimes claim to be the 51st state: We had dozens of USAF bases and still have 2 major ones close by. You can actually pay in dollars at some shops. The U2s and TR1s used to fly out of Mildenhall - very noisy exit (full of fuel?) but virtually a gliding return. One of my friends got involved with US-UK friendship organisations and was invited onto the base to be involved in a U2 landing. They sat on the end of the runway in a Ford Mustang as the plane approached, then raced it down the runway to grab the wing tip as it came to rest. If there was enough wind the pilot could hold it level anyway. Seems strange they could not have engineered in retractable wheels at the tips.

I have a feeling that when they used them over N. Korea they said they were still in use for weather research, and they just had to be returned to the military - but how much military work has been done under the guise of 'weather research'?

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#25
In reply to #12

Re: U2 Replacement?

05/15/2009 1:26 AM

imho : maybe if that aircraft could have refueled in flight the extra weight of an alighting gear could have been afforded

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Guru

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#26
In reply to #25

Re: U2 Replacement?

05/15/2009 1:58 AM

U2:

To protect the wings during landing, each wingtip has a titanium skid.

The large wingspan and resulting glider-like characteristics of the U-2 make it highly sensitive to crosswinds which, together with its tendency to float over the runway, makes the U-2 notoriously difficult to land. This results in a required chase car (usually a "souped-up" performance model including a Ford Mustang SSP, a Chevrolet Camaro B4C, and most recently a Pontiac GTO) and assistant who "talks" the pilot down by calling off the declining height of the aircraft in feet as it decreases air speed in order to overcome the cushion of air provided by the high-lift wings in ground effect.

Instead of the typical tricycle landing gear, consisting of a nose wheel and two sets of main wheels, one under each wing, the U-2 uses a bicycle configuration, with the forward set of main wheels located just behind the cockpit and the rear set of main wheels located behind the engine, coupled to the rudder in order to provide taxi steering.

To maintain balance while taxiing for takeoff, the ground crew installs two auxiliary wheels, called "pogos". These fit in sockets under each wing at about mid-span, and fall onto the runway as the aircraft takes off. To protect the wings during landing, each wingtip has a titanium skid. After the plane comes to a halt, the ground crew re-installs the pogos. The first pogo goes on the "light" or "up wing" while the other crew members use their weight to pull down the light side. Then two of the crew push up the heavy wing, allowing a third crew member to install a pogo on the other side.

SR71 Blackbird (Habu in Okinawa where the poison snake by that name lives.)

In order for the SR-71 to fly the worldwide missions, it has a special fleet of modified KC-135Q tankers for refueling. SR-71s run on JP-7 fuel, that fills the six large tanks in the fuselage. The component parts of the Blackbird fit very loosely together to allow for expansion at high temperatures. At rest on the ground, fuel leaks out constantly, since the tanks in the fuselage and wings only seal at operating temperatures. There is little danger of fire since the JP-7 fuel is very stable with an extremely high flash point.

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#23
In reply to #10

Re: U2 Replacement?

05/13/2009 8:26 PM

I would also suspect that they'd be alot less expensive.

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#13

Re: U2 Replacement?

05/13/2009 8:38 AM

I don't know what you'll find to take you to 100,000 feet, but this motorglider was setting altitude records (for non-pressurized cabins) from the '60s onward.

http://www.pilotfriend.com/aircraft%20performance/fournier/fournier.htm#r

Check it out. It's an interesting aircraft. I believe it's still being manufactured.

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#14

Re: U2 Replacement?

05/13/2009 8:43 AM

Of aircraft that fulfills similar mission, I think Global Hawk is what I see in our current public arsenal. But its published ceiling is 65,000ft or 20,000m, and cruising speed of 404 mph or 650 kph for 36 hour max. (info from Wikipedia) ... So with a range of about 14,400 miles, and with the earth's circumference of 24,900 mi (approx), it can't quite do a 'round the world tour' without refueling at least once.

Actually the Darkstar craft is visually more appealing to me, but its altitude and range are a bit more limited.

For comparison, the U2 cruised at 429mph (max speed 500mph), range of 6,405 miles, endurance 12 hours, and published ceiling of 85,000+ feet.

What kind of a glide ration is a U2 proported to have?

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#15
In reply to #14

Re: U2 Replacement?

05/13/2009 9:26 AM

It appears a U2's Glide Ration is one bale of hay per flight!

But seriously, the site http://forum.keypublishing.co.uk/archive/index.php?t-57689.html quotes a glide ratio of 28 for the U2, airliners 17 to 26, Vulcan bomber 24, Global Hawk 37, best sailplanes about 60 - but remember that is for quite low speed flight (indeed, some model gliders probably fly faster than full size ones!). I believe high altitude is equivalent to high Mach numbers?

I remember reading a description of U2 sorties over Russia where it was said that the Russians had interceptors that could get as high but control was so vague that they became useless, whereas the U2 was still under full control. So the ability to get high is not the only factor of importance.

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#29
In reply to #15

Re: U2 Replacement?

05/15/2009 1:57 PM

my memory: the fighters could get to their max ceiling ..within missle envelope, but that they , the fighters , were " stalling " at full power , aoa, and firing.. in a " hope" mode.. then " fall off " and recover..

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#16

Re: U2 Replacement?

05/13/2009 10:55 AM

The Northrop Grumman Global Hawk is effectively the U-2 replacement. I believe that it does not operate at quite the alititude of the U-2 (60,000 to 65,000 ft instead of 75,000+ feet), but does offer the advantage of not being limited by the human element in the cockpit.

As for glide ratio at altitude, that is purely a function of lift to drag ratio and is essentially constant for all altitudes. Reynolds number effects enter into the equation, but as a second-order effect. At high altitude, both lift and drag are functions of air density. The result is that for a fixed weight (lift required), velocity must increase with altitude in order to provide that lift. For all practical purposes, Indicated (actually Calibrated) Airspeed has to remain constant for constant lift. However, True Airspeed increases. The catch is that compressibility effects and flutter are driven by True Airspeed. At some altitude, this results in the stall speed (IAS or CAS) occurring at the same True Airspeed as either the flutter limit (aircraft structure) or the onset of compressibility-driven control effects. This was what the U-2 community referred to as the "coffin corner". The SR-71 Blackbird approached this in a different manner, but could hardly be called a "powered glider".

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#17

Re: U2 Replacement?

05/13/2009 1:05 PM

I believe the U-2 still holds the record for highest altitude sustained level flight. The SR-71 was/is the record holder for speed. Once went coast-to-coast in 58 minutes! including several re-fuelings.

Above 75,000 feet, conventional control surfaces are ineffective unless the craft is supersonic which the U-2 is not. The 'coffin corner' effect is very real for sub-sonic aircraft. Even airliners are altitude limited by the requirement they maintain a safe margin above aerodynamic stall (usually 1.3)

U2's I was once told by a partner that few them (and F104's, B-58, SR-71) they would fly hours in the U-2 less than 5 knots above stall, could not go any faster due to thrust limits. He taught me how to fly motor-glider (30:1 glide ratio) VERY PRECISELY. +/- 5 knots was too much speed error, +/- 20 feet in altitude holding was his limit.

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#18
In reply to #17

Re: U2 Replacement?

05/13/2009 1:15 PM

Thanks to everyone for this informative discussion.

We have flown (well if flying is hanging below a balloon) for 47 missions for many schools and groups like Boy Scouts etc.

But one of thee groups showed interest instead of the usual flight profile of fly to max altitude of the balloon and then come down via the parachute, but to instead try to using a glider try to fly it back to the launch sites location.

At the time i knoew of only three vehicles that have operated at these altitudes,

The x-15

The Black bird

and the U-2

Since this is a non powered flight that throws out the first two, and leaves the U-2 as the only possibility..

I jhave heard at times the excellent slope ratio it was capable of, Like it could run out of fuel at altitude and glide thousands of miles back to it's base and land. so I thought this has the best chance of success.

Whats everyone think U-2? or something better?


Joe

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#19
In reply to #18

Re: U2 Replacement?

05/13/2009 3:29 PM

Just a few years ago, NASA ran a project for a HALE (High Altitude, Long Endurance) aircraft using a standard sailplane configured as a UAV and carried aloft by a balloon for launch. I don't know if they ever actually flew or if it was just a study. I seem to remember that the sailplane was roughly a 40 to 1 glide ratio aircraft.

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#21

Re: U2 Replacement?

05/13/2009 5:03 PM

Written without doing the sums - but:

In principle, if we scale the velocities and atmospheric densities (but ignore little features like strength), it would be unsurprising if the designs for low-altitude gliders were also good candidates for a high-altitude powered aircraft. Conversely, the shape of a jumbo jet would possibly make a decent candidate for a lightweight glider at pressures of 10-atmospheres or more.

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#27

Re: U2 Replacement?

05/15/2009 2:43 AM

could the lifting body of the shuttle be more of what you envision ?

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#30
In reply to #27

Re: U2 Replacement?

05/15/2009 2:49 PM

No,


The Shuttle has the gliding capability of a brick.

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#31
In reply to #30

Re: U2 Replacement?

05/16/2009 12:43 AM

Remember that the shuttle is designed not to soar, but rather to return to earth in a controlled manner. High drag is good for the shuttle's purposes.

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Guru

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#28

Re: U2 Replacement?

05/15/2009 3:00 AM

Since 1980 AeroVironment, Inc. (founded in 1971 by the ultra-light airplane innovator--Dr. Paul MacCready) has been experimenting with solar-powered aircraft, often in conjunction with the NASA Dryden Flight Research Center, Edwards, California. Thus far, AeroVironment, now headquartered in Monrovia, California, has achieved several altitude records with its Solar Challenger, Pathfinder, and Pathfinder-Plus aircraft. It expects to exceed these records with the newer and larger solar-powered Centurion and its successors the Centelios and Helios vehicles, in the NASA Environmental Research Aircraft and Sensor Technology (ERAST) program.

The Centurion is a lightweight, solar-powered, remotely piloted flying wing aircraft that is demonstrating the technology of applying solar power for long-duration, high-altitude flight. It is considered to be a prototype technology demonstrator for a future fleet of solar-powered aircraft that could stay airborne for weeks or months on scientific sampling and imaging missions or while serving as telecommunications relay platforms. Although it shares many of the design concepts of the Pathfinder, the Centurion has a wingspan of 206 feet, more than twice the 98-foot span of the original Pathfinder and 70-percent longer than the Pathfinder-Plus' 121-foot span. At the same time, Centurion maintains the 8-foot chord (front to rear distance) of the Pathfinder wing, giving the wing an aspect ratio (length-to-chord) of 26 to 1.

This are also pretty cool:

http://www.space.com/businesstechnology/business/erast_planes.html

http://www.scaled.com/projects/proteus.html

They are working on it.

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