Wednesday, February 16, 2011

B2 Spirit Block 30 Upgrades

Northrop Grumman has completed the final stage of avionics for the B-2 Spirit Stealth bomber.
Named Block 10, Block20 and Block 30 versions, It has carried out numerous avionics and flight software upgrades ever since the first B-2 was delivered to the USAF in 1994-95.The aircraft is aerodynamically unstable, kept in the air with a quadruple-redundant fly-by-wire (FBW) system, under the control of a General Electric Flight Control Computer (FCC).


The block 10 couldn't fly at full flight loads, lacked precision weapons guidance and terrain following capability, and had a limited DMS ( Digital Mapping system) .In DMS, a collection of data is compiled and formatted into a virtual image. 


The primary function of this technology is to produce maps that give accurate representations of a particular area, detailing major road arteries and other points of interest. The technology also allows the calculation of distances from once place to another , which would enable the B-2 to perform calculated attack missions.


 Eight "Block 20" aircraft were delivered in 1996 and 1997, which were up to operational specification, along with some improvements such as a Global Positioning System (GPS) satellite navigation receiver. The GPS receiver system was integrated into a "GPS Aided Targeting System (GATS)" to support the GAM GPS-guided bomb, and later the JDAM (Joint Direct Attack Munition)and other GPS-guided weapons. 


The Global Positioning System Aided Munition (GAM) was developed by the Air Force and Northrop Grumman Corporation as an interim precision munition for the B-2. GAM is a tail kit that fits on the 2,000-pound Mk84 general purpose bomb [GBU-36/B], or the 4,500 lb BLU-113 penetrator [GBU-37/B]. GAM uses GPS guidance to more accurately guide to target locations.


This weapon is currently the only all-weather, near-precision "bunker busting " capability available.



The Global Positioning System (GPS) Aided Target System [GATS] is an all weather B-2 targeting system which reduces Target Location Error (TLE) normally associated with target coordinates. 

By exploiting the synergistic effects of the B-2s GPS navigation and Synthetic Aperture Radar (SAR) capabilities, which combine the SARs excellent range and range rate capabilities with accurate GPS Position and velocity information, it will provide the GAM highly accurate target location relative to current B-2 position.


The ten Block 10s were brought up to Block 20 specification.


Significant Enhancements in Block 30 B-2s:


The Block 20s were followed by two final new-build "Block 30" aircraft, with the older machines brought up to the same specification. 
The Block 30s have avionics improvements, including a satellite communications (SATCOM) link; the lidar contrail-detection system; support for new GPS-guided weapons; and in particular have substantial modifications to improve their stealthiness.


Northrop Grumman has begun flight testing the new computing hardware and communications infrastructure that will eventually allow the B-2 stealth bomber to send and receive battlefield information by satellite more than 100 times faster than today.


The flight test program is part of Increment 1 of the U.S. Air Force's B-2 extremely high frequency (EHF) satellite communications program.



The EHF Increment 1 system that flew includes:

  • A new integrated processing unit developed by Lockheed Martin Systems Integration,  will replace up to a dozen current stand-alone avionics computers on the B-2;
  • A new disk drive unit developed by Honeywell Defense and Space Electronic Systems, Plymouth, Minn., will enable transfer of EHF data onto and off of the B-2; and
  • A network of fiber optic cable that will support the high speed data transfers within the aircraft.
Increment 2 involves installation of a new communications terminal and new antennas that will allow the B-2 to transmit and receive information securely via satellite. Increment 3 will integrate the B-2 into the U.S. Department of Defense's Global Information Grid, a worldwide network of information systems, processes and personnel involved in collecting, storing, managing and disseminating information on demand to warfighters, policy makers and military support personnel.


 Adding the new stealth features require stripping off all the aircraft's paint and RAM and performing some airframe changes.

Monday, February 14, 2011

Naval Eurofighter Typhoon vs F/A-18 for the Indian Navy

Eurofighter GmBh has announced  in Aero India 2011 that it is in talks with India to jointly develop a naval version of the Eurofighter Typhoon, especially for the Indian Navy.
   In its flyer issued on 11 Feb, Eurofighter GmBh has outlined the potential advantages of the Naval variant, as compared to the American F/A-18 Hornet , which it describes as " heavy,slow and not capable of facing advanced threats "     ( talk about offensive advertising :-P ).



See it here:
http://2.bp.blogspot.com/-dY8O2tinLyU/TVks--Iv6hI/AAAAAAAAMxo/e3RvN-D0F74/s1600/Typhoon%2BIN.JPG


The Eurofighter Typhoon



How the proposed Naval  Eurofighter Typhoon  measures up with the F/A-18 :- 

Engine modifications : The naval variant is offering helmet mounted cueing system (HMCS) and thrust vectoring as its two core technologies... This would enable the aircraft to land more safely on aircraft carriers, negating the use of  arrestor cables. The arrestor frame caused unnecessary aerodynamic drag to the aircraft, coupled with increased landing difficulty , such as the F/A -18.

It must be noted that Thrust Vectoring is a capability which even the F/A-18 doesn`t have. Currently the NASA experimental version of the F/A-18 uses thrust vectoring , though it has not been used by any section of the military as yet.

Avionics : The naval typhoon offers AESA ( Active Electronically Scanned Array ) radar , whereas the F/A-18 has the old AN/APG-65 radar. obviously here, the AESA radar offers much better protection to the Fighter by transmitting powerful signals without remaining much visible to enemy radars.
Incidentally, the AESA radar is used in advanced 5th generation fighters like the F-22 raptor and the F-35 Lightening II.

Performance : As far as performance is concerned , the Typhoon is admittedly much more superior to the F/A-18 in terms of maneuverability , agility , fuel burn and overall handling. Further, the Typhoon can accelerate to Mach 1.5, without afterburners !  This would be a great capability any navy would want to have.

Radar Signature : Typhoon has great measures taken to reduce its radar signature - less than 1 sq. metre. Although not a stealth fighter, radar detection is significantly more difficult  compared to other fighters in its class. The F-18 has significantly more cross section and hence a greater radar signature.

Other Factors :  The Indian Navy may be interested in this offer from another politico-management point of view.

On any day, Typhoon`s maintenance and spare parts would be more reliable, compared to what the US can offer, due to its ever changing domineering foreign policy, sanctions , export restrictions etc.

Also,Eurofighter GmBh is seriously pursuing India for joint development programs and technology transfer for the naval typhoon, which means that soon, Indian companies will be churning out future typhoons the same way HAL manufactures Sukhoi 30-MKIs.

A note to add : The current comparison is with the classic F/A- 18 which is currently in use by many nations world over.
The F/A-18 Super Hornet, is the latest variant by Boeing which has better avionics and features compared to the F/A-18, like the AESA radar, and is more or less at par with the Typhoon.

Avionics have been the major thrust in this variant, in addition to airframe changes which have resulted it in being 20 % larger and heavier by 3200 Kg. On the other hand, there is a 40% increase in range.

But again, in an aircraft carrier, range is not as important a criterion than the weight and takeoff/landing capabilities are.Here , the Typhoon still scores over.

Anyhow, lets not forget that the naval typhoon is still in the design stage and no prototype has been flown yet.Compare this to the F/A-18`s impressive naval track record.
There is some real thinking to do on the part of the Indian Navy.

On the whole, it will be interesting to see India`s response to this proposal.
AirborneGeeks will keep you updated.


Sunday, February 13, 2011

The Next Revolution - Anti Stealth Technology

Anyone who has an idea about stealth technology would marvel at its capabilities, and most of the world considers them to be a "game changer" in an actual battlefield scenario.
       This is true, if , and only if , detection methods don`t evolve.. and it is already evolving, but maybe not gaining media glare `cos of the undulating hype surrounding stealth. Anti -Stealth technology is fast becoming a reality , thanks to some ingenious thinkers who refuse to accept the "Stealth is God" school of thought.

 In fact, most of the current anti-stealth detection theories are not based on hi-fi sci-tech concepts but on crude, and dangerously practical ,scientific common sense. Yes, stealth vehicles can be detected. , if present estimates are to go by.

How it is done :-

The most astonishingly "simple" method which I`v seen is by using Radio telescopes - those astronomical instruments which scientists have used for decades to observe the star and constellation activities , now in  catching Stealth Aircraft !!! Here is how:

1) Radio telescopes and radars don`t emit waves on their own, but receive radio signals from stars.All stars emit radio signals, and the radar receives all of them. 
All astronomical agencies have a definitive " Star map" of a region, which shows the actual number of stars whose radio waves are received by the radars, and their respective intensities ( based upon the star`s distance from earth)

2)  Any "obstruction" or "barrier" in the sky between the radar and the stars would result in a definite loss of signal strength or quality  being received by the radar base station.

3) Hope you got the trick :-). Now, in the event of a stealth plane in the skies, it would absorb the radio waves by default, which would prevent the star radio signals reaching the radar.

4) The radar computer shows a loss in signal , pinpointing the location - the "void"  in the sky from where signal loss is detected
And that "void", is nothing but our flying stealth beauty :-).
         Once this is done, computers are smart enough to calculate the distance,speed and shape of the plane.There are ideas on equipping these bases with SAMs ( Surface-to-Air Missiles) to send it to oblivion :-P.

On second thoughts,
It may take time to this plan to be foolproof since the star map has to be accurate enough , lest there be false alerts. 
Also, this requires really sensitive and high aperture radio telescopes, coupled with some really fast computers.This is a challenge, but will be overcome in the near future.

Anti-Stealth radars do exist at present ( Widely rumored to be the Russian Tamara radar), but any information on them is highly regulated,which makes the average non-military observer difficult to comment on its actual capabilities. 
A US Airforce Stealth F-117A was shot down in Kosovo a few years back , apparently after being "detected" after it flew in the rain.... making it radar-visible.

Various theories abound, but none confirmed yet. The shroud of secrecy over the actual efficacy of stealth is also a pending issue.
But anyhow,once the global wide-eyed admiration for Stealth comes to normal, Anti-Stealth will come to light.
Till then, speculation rules the roost.

Saturday, February 12, 2011

How does a Stealth Aircraft Work?

" Stealth " has been probably the most repeated word in military aviation for the past few years. Now comes the basic question that many have - what is it and how does such an aircraft work?

Stealth is just the ability of an object to prevent itself from being detected by a radar. A radar basically sends out radio waves into the sky ,which then bounces off the bodies of aircraft and returns , to be detected by the radar computer.
          Now, the amount of radar rays "reflected" by an aircraft is called its "Radar Signature ", which is used to calculate its size,speed and the location.

To be undetected, an aircraft must fly either too high ( which makes it impossible to hit targets on ground accurately) , or too low to be detected by a radar ( no need of radars, it becomes visible to naked eye :-) ).
This leaves with only one option- to fly normally and stop reflecting radio waves.
Easier said than done isn`t it? But yes, there are ways :-

1) Using a RAM ( No, not your computer RAM) which is, the Radar Absorbent Material. This is a coating on the airplane surface which precisely does the same thing- absorb radio waves,and scatter `em in all directions undetectable by the radar. Eg. wood powder and other chemical compounds, which are kept top secret, for obvious reasons.

2)Having a sleek, smooth aerodynamic design. This reduces the "cross section area"of the plane.lesser the area, lesser the radio wave reflection. Common sense , isn't it? Have a look at the pictures below:

A Stealth Aircraft

A traditional large Aircraft
                        
Due to these, the Radar Signature for stealth planes is very very less... almost like that of a bird ( for the B-2 Stealth bomber shown above) compared to the traditional plane ( the B-52 bomber) whose signature is about that of a huge trailer truck !
        Now you may get an idea of how difficult it would be to deal with stealth fighters/bombers in an actual battle scenario.. no wonder countries around the world are scrambling to get hold of these beauties- The B2 Spirit,F-22 Raptor,F-35 Lightening II , and many more under development in labs around the world.No Radar could possibly see it, and the hideous birds can play havoc in enemy territory. Boom !Boom!Boom!
It would be pretty much like finding a needle in a haystack.
     So..... A stealth plane could be a road to total aerial dominance right?Not quite.. Technology always evolves, and it does so in this case too.
As they say, every great warrior has his Achilles`s heel :-)
More on that in my next post.

Friday, February 11, 2011

The Advent of the Flying Wing

As I mentioned in my previous post, the BWB design had been there for decades, before it came to reality. It was ( and still is) more commonly known as the "Flying Wing". Though some German aviators had toyed with the idea, the actual pioneer behind this was none other than Jack Northrop, the founder of the Northrop Grumman Aircraft company.
         Despite the positives, the "flying wing" has many challenges to overcome before it becomes a public reality.The main reason being that it is aerodynamically unstable - due to the presence of only a single wing, there are no fins, rudders, tails etc. These are the vital parts that provide the much needed control to the pilot to maneuver the airplane. Their absence results in two effects:

1) Reduced drag on the aircraft , and thus greater efficiency and speed.

2) Poor stability due to lack of control options.This makes the flying wing inherently risky for any pilot.

3) Large wingspan, which made it physically difficult to accomodate in airports.

                Apart from this, there are very few windows in the seating area, and it is difficult to pressurize the entire cabin due to its eccentric shape.

The trouble with the flying wings in the past :-

One of the most important components of a flying wing aircraft are on-board computers. One of the earliest Flying wings was the Northrop YB-49... with a 53 foot wingspan and 8 General Electric turbojet engines, this was  really , really large aircraft for its time ( the 1940s).
        As mentioned before, it was highly unstable. Pilots had a hard time keeping it on leash, and by the end of the decade, the US Airforce had all the jets scrapped.
The reason - Lack of a common control mechanism which could help the pilot in maintaining optimum parameters for each of the engines, wings etc. , which could not be otherwise possible manually.
Herein arose the need for a computer, which could carry out these operations with minimal human interference, and thus maintain the much elusive aerodynamic stability required by the flying wing. And as you all know, the 1950s was not the computer age.


 Hmm...What was done to overcome it :-


So just when you thought that flying this thing would be a straight ticket to heaven, some really ultra brilliant aero geeks ( read : Aerospace engineers at Northrop Grumman ) found ways out to bypass it with
The Fly-by-Wire system ( More about that in my future posts ) But more significantly, it used on-board aircraft computers to control various flight parameters, for a safe,healthy flight :-).

This colossal effort,made the flying wing became a worldwide phenomenon once it was introduced in one of the most admired aircraft of all times - The B-2 Spirit Stealth Bomber, in 1989.
Trendsetter- The B-2 Stealth Bomber

With 130 on-board computers ( !!! ), the B-2 was an airborne computing powerhouse controlling every aspect of its flight- weather,engines,targeting,autopilots etc. etc. Pilots spent a whopping 40 hours in continuous flight, aided by mid air refueling and laptop computers, into which they could ( quite literally) key in their whims and fancies, which the computer faithfully obeyed.

This machine became an overnight sensation, being one of a kind - with an equally potent destructive power.
But more importantly,after almost 4 decades of struggle, the Flying wing had finally come of age.



Wednesday, February 9, 2011

Blended Wing Body Aircraft- Carriers of the future

As the battle between the aviation giants for global markets rages on, Boeing and the NASA are quietly working on the next generation of civil transport- the Blended Wing Body ( BWB )design.
This radical aerodynamic concept had been in the offing for many decades, since the time of Jack Northrop   ( Northrop Grumman`s founder and inventor of the flying wing design) but has gathered serious interest due to its massive technical and economic gains compared to conventional aircraft design.
The most significant feature in the BWB is  that all the components- fuselage,wings , engines and other control surfaces are integrated into a single aerodynamic surface, as shown in the figure below ( Courtesy: Virginia Tech, US)
Why the BWB is making heads turn:- 

1. Simple Economics :    Higher Fuel Efficiency = Lesser money spent (as much as 32 % ) for long distance flights, which will be the hallmark of the BWB aircraft.

2. Lesser number of engines :   You don`t have to be an Aviation freak to understand this :-).For generating the same force, Airbus`s hunk.. the huge A380 needs FOUR engines, while our BWB babe takes it cool on only THREE.
 
3.The "Save Mother Earth" junta : The BWB generates lesser noise , due to the favorable positioning of the engines and its interaction with the airframe. Further, lower emissions due to the lesser fuel it drinks up.

4. Carry more passengers : This thing lifts more passengers . Boeing has anticipated designs that can carry upto 1000 passengers ( Though this concept remains only on paper now ).As of now, its working on a toned down version taking 450-500 passengers.

5. It looks Beautiful !  : Man... One look at the BWB X48-B concept aircraft reminds me of the wandering albatross... huge wingspan.. wide wings .. To me,it doesn`t in anyway bring in the "fear factor" a potential US Air Force bomber would have.Nothing they could do about that, though :-) .

Boeing X-48B UAV in flight
The Albatross-Find any similarity?:-)






















So the big deal is...

As with all high-profile Aero projects in the US, The military will be the first beneficiary of this , with flight testing of the Boeing X48-B unmanned BWB aircraft in progress.

Civilian versions will be probably be reality in a couple of decades, if some pressing issues in the BWB are sorted out. More on that in my next post.....

For more inquisitive people, I have cut a lot of  technical mumbo-jumbo in this post,so forgive me for having left the finer details. Having a look at the following white paper by the Virginia Tech University would throw some light.

www.aoe.vt.edu/research/groups/bwb/papers/TheBWBAircraft.pdf

Also,

 http://www.hightech-edge.com/boeing-x48b-unmanned-blended-wing-body-aircraft/799/


Please Post your comments on your opinion.. I`l be glad to reply.








Tuesday, February 8, 2011

Aircraft flying for 5 years without refuelling - The DARPA way

Some time back I had watched a documentary by National Geographic " America`s Secret Weapons", which essentially featured DARPA in seemingly insane , but credible pursuits...robots attached to soldiers, diving speed enhancing equipment, and RPG ( Rocket Propelled Grenades) avoidance system for Humvees etc.
 But of the many futuristic projects DARPA is engaged in, the one which caught my eye was that of designing and flying aircraft that could stay aloft in the sky for  5 Years !!!
Now, the project has come to fruit, if Boeing`s latest contract with DARPA for $89 million is anything to go by. Named as "Project Vulture" the aircraft will be a solar powered , flying in the stratosphere.The electricity stored by the fuel cells will power the electric motors for the propellers and the systems.DARPA believes that the Vulture will combine positive aspects of both satellites and aircraft in providing a strategic advantage to the operator, also in terms of the cost involved.
As always, there is room for skepticism as to its efficacy. If the Vulture is to derive solar power, it would have to  fly constantly over the clouds , facing the sun. The "Zephyr" was a predecessor , which used solar power to fly non stop 2 weeks. Herein lies the catch :  Zephyr flew in Arizona, which is just about 30 degrees above the equator.The solar power is much higher in the equator and tropics compared to the northern and southern latitudes. Otherwise the accompanying loss of solar power would easily ground the aircraft in these regions and other wintry areas. If the Vulture is to overcome this, it would require truly phenomenal fuel cell conversion efficiencies than those available today, which stands at about 35-40 %.
                                                        The Zephyr`s Flight
But there is sense in the US Military`s requirements, most of which would be in the arid ,sunny  regions of the middle east and Asia; where the Vulture can perform well in spite of the current constraints.The present contract to Boeing would initially fly a prototype non stop for 30 days, for testing . But the project duration stumps me..... would DARPA do a test to actually check if the thing can stay aloft and kiss the skies for 5 years?Even if these geniuses do pull it off, It would be a tragic comedy if it fails after .. say.. 3 or 3.5 years in perpetual flight.
So the next question... test it AGAIN?Or better still , the easier option- change the program objectives to suit a 3 year flight.....
Now THAT.. is food for thought :-).

Why is Airbus Military is yet to make a mark?

Looks like Airbus Military is facing trouble again........... After UK and South Africa,its Germany`s latest  decision to cut its orders for Airbus A400M tactical transport aircraft by reselling 13 of its 50 aircraft on order to " save costs".The present cuts, as a part of Germany`s reduced defence spending strategy, have further cast doubts on the commercial  success of the highly publicized, over-budget program , which attempts to eclipse Lockheed Martin`s highly reliable and  C-130 and C-17 as the market leader in this area.


However, the larger point to note is Airbus Military`s virtual "struggle" to compete in the highly lucrative military aviation sector, which is dominated by its arch rival in the commercial arena- Boeing. It seems Airbus has not yet fully focused its energies in tapping the military market.A casual comparison of http://www.airbusmilitary.com (Airbus Military)  and http://www.boeing.com/bds/phantom_works/index.html (Boeing Phantom Works) will show the vast difference between the two.... Boeing`s range of dozens of aircraft to Airbus`s 4 planes , with some variants (I have not compared with Lockheed Martin since it specializes only in military aviation) which makes me wonder the reason for Airbus Military`s  inability to match its big brother Airbus Commercial`s market power and product range, despite being one of the most respected names in the aviation industry.
The reason may be attributed to entirely financial  reasons, as well as the spending power of the EADS member nations ( France, Germany,Spain,UK,Italy etc. ). The United States pumps in billions of dollars annually into Boeing R & D centers , in addition to what the bosses at Boeing spend themselves in University partnerships and research.
On the other hand, Hardly anything can be said for the EU nations, which had suffered "massive" losses due to the cost escalation of the Airbus A400-M program ( talk about the billions the US had invested in numerous experimental aircraft before throwing the program down the drain :-)   ) . With European economy hardly going strong,  R & D funding can be a hard ball to catch for Airbus Military. The A400-M program has been seen as AM`s strongest response to critics who undermine its military capabilities, but with its orders dwindling and prices soaring, it seems the AM guys sure have some bad weather to navigate through.
Lets hope AM gives Boeing Phantom Works a run for its money... Aviation geeks would love to see a little more competition in the air :-)