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Wednesday, August 17, 2011

Black Widow II vs Raptor

Did the USAF Choose the Wrong Jet?

The Advanced Tactical Fighter (ATF) program began in 1981 amidst fears of the increased lethality of the newest generation of Russian fighters, the Su-27 and Mig-29. Soviet integrated air defense systems made intrusion into Soviet airspace by non-stealthy aircraft like the F-15 extremely difficult. Thus, the USAF decided it needed a new generation of air superiority fighters to overcome these challenges. The Advanced Tactical Fighter program was born.

"In 1981, the Air Force developed a requirement for an Advanced Tactical Fighter as a new air superiority fighter. It would take advantage of the new technologies in fighter design on the horizon including composite materials, lightweight alloys, advanced flight control systems, higher power propulsion systems and stealth technology. Air Force leaders believed these new technologies would make aircraft like the F-15 and F-16 obsolete by the early 21st century. " - Global Security

Eventually Northrop and McDonnell Douglas teamed up to design the YF-23 for the competition while Boeing, Lockheed Martin, and General Dynamics designed the YF-22. By the time the USAF requested a proposal from Northrup in 1985, it was arguably the most experienced company (along with Lockheed) in designing low observable aircraft. Northrup had already started work on the B-2 Spirit stealth bomber. McDonnell Douglas was one of the most respected names in the aerospace industry. McDonnell Douglas was responsible for the creation of some of the finest military equipment in use such as the F-15 Eagle, AH-64 Apache, and Tomahawk cruise missile. The YF-23 design reflects the immense skill of the Northrup and McDonnell Douglas design teams.

Interview with ATF test pilot Paul Metz, first pilot to fly the YF-23

Head to Head comparison YF-22 vs YF-23

Both airframes have advantages and disadvantages over one another in the case of the YF-22 and YF-23. One of the main advantages the YF-23 held over the YF-22 was that it was stealthier. But, to the extent of which its rcs is smaller is not public information. It is known that the YF-23 has a smaller rcs than .0001m^2 (40 dBSM) as that is the Raptor's frontal rcs. However, I would guess that the YF-23 was stealthier by a wide margin due to its unique tail design.

"The YF-23 was stealthier than the F-22 Raptor. The two ruddervators reduce the Radar Cross Signature of the YF-23 significantly. This is because instead of having four extremely large control surfaces on the tail, there are only two. The F-22 Raptor design utilizes the traditional configuration of two rudders, which are canted outward, and two elevators. This make the RCS larger. Another RCS reducing feature is the engines. These are mounted in nacelles in the wing that blend gracefully into the wing on the top, and form an extension of the fueslage on the bottom. The larger bottom fuselage lets it pack more missiles and other expendable weapons. The intake duct is angled up and inward to reflect radar beams and keep them from hitting the fast moving compressor face. The intake duct starts on the lower edge of the wing and moves through it onto the top of the wing. This feature can also reduce the RCS signature from a look down-shoot down radar from an aircraft flying overhead. Also reducing the RCS, is the way the leading and trailing edge of all surfaces are angled. All of the leading and trailing edges are angled the same. Therefore, the front of the right wing is parallel to the left wing's trailing edge, and the left section of the nose. For example, the leading edge of the wing is parallel to the trailing edge of the wing on the other side. " - Global Security

Because of its substantial stealth capabilities, Northrup named the YF-23 Black Widow II. The name "Grey Ghost" also become associated with the YF-23. However, this increased stealthiness came at a cost, agility.

"The YF-23 was optimized for speed, range and stealth at some expense in agility, compared to its rival. The general layout is unique and exploits much of the design technique developed in the B-2A ATB program. RCS is reduced through careful planform shaping and blending, with a unique low drag tail which conceals dorsal exhausts in troughs to reduce both RCS and IR emissions" - Air Power Australia, 1991

The YF-23 design DID NOT feature thrust vectoring as the Northrup design team did not want to add extra weight to the aircraft or increase its radar signature. (National Museum of the Air Force, 2009) Even without thrust vectoring, the YF-23 was incredibly agile as it was able to reach all of the ATF maneuverability qualifications. Something the YF-22 could not do without the aid of thrust vectoring. (Air Power Australia, 2005)

On April 23rd 1991, Secretary of the Air Force Donald Rice announced the YF-22 was the winner of the competition. So did the Air Force pick the wrong jet? To answer this question, one must understand why the YF-22 won the competition. The USAF chose the YF-22 because of its incredible maneuverability. Although the YF-23 was stealthier, the YF-22 was already incredibly stealthy relative to anything else in service. The F-22A is still the stealthiest aircraft in the USAF inventory and the stealthiest aircraft in service in all the world's air forces' for the foreseeable future. Another selling point to the YF-22 was that its design was more compatible for the Navy's own Advanced Tactical Fighter program, the NATF. However, the Navy cancelled the NATF in 1992, a year after the ATF ended.

In my opinion, the YF-22 won the competition narrowly but fairly. However, Lockheed's victory does not diminish the fact that the YF-23 is still an extraordinary and incredibly innovative airframe. I think BOTH airframes should have been utilized in a similar fashion as to what happened after the conclusion of the Lightweight Fighter program. The Lightweight Fighter program produced such outstanding jets that both of them were eventually utilized albeit the YF-17 altered. Although the YF-16 defeated the YF-17,McDonnell Douglas saw the potential in the YF-17 design and eventually designed the F/A-18 Hornet, one of the most successful naval aircraft in modern history. The F/A-18 eventually fulfilled the Navy's requirement for a new fighter. In the same way, the YF-23 can fulfill the USAF's requirement for the interim bomber program. The program called for a medium range stealth bomber operational by 2018. With some adjustments, the YF-23 could easily be suited for this role. In fact, Northrup tried just that. Unfortunately for Northrup, the DOD latter concluded that it need a bomber with a much greater range. Thus, the USAF created the Next Generation Bomber project.


On another note, this illustration shows what design changes Lockheed made from the YF-22 to the F-22A. Among the changes is a reduction from 25,000 pounds of internal fuel to closer to 21,000 pounds. (Air Power Australia, 2005)

The following image is from Defense Industry Daily

Saturday, August 13, 2011

US Navy vs PLA Navy

China's new carrier. Although its not without its fair share of problems.

Relax: China’s First Aircraft Carrier is a Piece of Junk, By David Axe

"Shi Lang will sail into a Pacific Ocean teeming with carriers. First, there are the American carriers: five nuclear-powered supercarriers home-ported in California, Washington and Japan, plus six assault ships in California and Japan. Between them, the American carriers displace no less than 700,000 tons and can carry 600 aircraft." -David Axe

Our Navy can carry twice as many aircraft at sea as all the rest of the world combined” - Robert Gates, former US Defense Secretary

Short tons
US Navy
1,197,284(11) Super Carriers
402,280 (9) Assault Ships
393,032 (54) Nuclear Powered Attack Submarines
337,500 (18) Nuclear Powered ICBM Submarines
241,472 (22) Guided Missile Cruisers
581,720 (60) Destroyers
137,760 (19) Frigates
3,241,536 204

PLA Navy
70,000 (1) Carrier
61,600 (8) Nuclear Powered Submarines
156,778 (58) Diesel-Electric Submarines
229,262 (26) Destroyers
108,612 (51) Frigates
626,252 144

The U.S Navy maintains dominance over the World's ocean with a fleet displacement as large as the next 13 nation's under it combined. I did not even include the support and resupply ships in the calculation of tonnage. If I did, it would be even larger. The US Navy operates a total of 286 ships.


The PLAAF has many "showy" items such as fighter aircraft but lacks the support and logistics units that make the rest of the force formidable. For example, China only has 10 tanker aircraft as opposed to the USAF's 477. This severely limits the range of PLAAF aircraft and restricts them from operating beyond their region. Additionally, the PLAAF lacks widespread AWACS capabilities. Meaning that their command and control capabilities as well as battle field awareness is severely hindered. The U.S has 59 as opposed to China's 4. One aspect missing from this chart I created is intelligence assets such as UAVs and reconnaissance planes. A contingent of U.S RQ-4B Global Hawks has been recently stationed in Guam. These reconnaissance aircraft can keep vigil for over a day at a time while scanning thousands of miles of ocean.
"In a world where knowledge equals power, the RQ-4 is among the most powerful aircraft ever." -David Axe

China lacks these immense intelligence gathering capabilities that the USAF posses. You can't hit what you can't see. China also lacks the unparalleled satellite coverage the U.S maintains. The US has over 400 military satellites which is four times the amount maintained by the runner up, Russia. Despite China's modernization program and and unveiling of the J-20, the PLAAF remains undeveloped and immature in comparison to the USAF. America may be in a state of decline, but the skies are firmly in our grasp.


Tuesday, August 9, 2011

F-35 Maneuverability Woes

The JSF program was envisioned to create a multi-role combat aircraft capable of both air-to-ground and air interdiction missions, a "strike fighter". This emphasis in dual role capabilities is directly reflected in the F-35's airframe. The F-35 lacks the maneuverability of a purebred fighter such as the F-22A or F-15C. To judge the effectiveness of the F-35 in air-to-air combat, examples from history provide insight.

The aircraft most similar to the F-35 in service with the USAF today is the General Dynamics F-16 Fighting Falcon. The F-16 has been used to great effect in air-to-ground missions during Operation Dessert Storm, Operation Enduring Freedom, and Operation Iraqi Freedom. While the USAF has drawn blood for F-16, most of the 67 kills achieved the F-16 have been done under the command of skilled Israeli pilots. The F-16 has achieved an impressive 47-0 kill ratio under the IAF. Many of these kills were achieved because of the F-16's dazzling maneuverability. This is a key difference between the F-16 and F-35.

Although the F-16 was intended to be a dual role aircraft, one of the stringent requirements of the F-XX program was for the new aircraft to feature high trust-to-weight ratio. This resulted in the F-16 being one of the earliest fighter aircraft to enter service with a thrust-to-weight ratio exceeding 1.0. The F-16's already spectacular maneuverability was enhanced further with the implication of revolutionary fly-by-wire technology. This degree of maneuverability provides the Falcon with lethal visual range combat capabilities. In contrast, the F-35 was rated as "Double Inferior" in regards to both vertical and horizontal maneuvering capabilities relative to modern Russian and Chinese fighter aircraft such as the Su-27, Su-30, Su-35, Mig-29M and Pak Fa. In fact, the RAND report went as far to say the F-35 has "Inferior acceleration,inferior climb,inferior sustained turn capability" relative to the compared aircraft. This lack in maneuverability is not something that incremental upgrades can solve over the F-35's service life. Rather, they are the permanent result of the F-35's design. Airframe design cannot be changed.

Thrust-to-weight ratios of fighter aircraft; 100% fuel followed by 50% internal fuel
All following calculations assume aircraft thrust using afterburner

F-35A .87 -> 1.07
Su-27K 1.07 -> 1.21
PAK FA* 1.19 (exact figures unknown as final version will feature different engines)
F-16C 1.095 -> 1.25
F-22A 1.08 -> 1.26

Instead of giving the F-35 a high thrust-to-weight ratio and high maneuverability, the design team at Lockheed placed their faith in Helmet Mounted Display (HMD) technology. The HMD allows pilots to literally look at a target to achieve missile lock. With the advent of off-boresight capability missiles such as the AIM-9X, pilots can look at aircraft up 90 degrees away, gain missile lock, and score a kill. If the HMD works as advertised  it could revolutionize the dogfight. However, if the HMD is not able to mitigate the extreme maneuverability of its opponents, that the F-35 is at disadvantage. The last time this much faith was placed on new technology without any back up plan was during the Vietnam War.

In the years prior to the Vietnam War the USAF developed a new theory that beyond visual range (bvr) missiles would be the future of the dogfight and that the traditional weapon of air superiority platforms, the gun, was obsolete. (RAND, 2008)It was also believed that aircraft did not need to be maneuverable as the missile would do most of the maneuvering from range.(APA, 2010) As a result, the F-4 Phantom was not maneuverable and did not feature a gun. Two missile designs were fielded by the USAF during the Vietnam War. The radar guided AIM-7 Sparrow which had a range greater than 20 miles was built for bvr engagements. The AIM-9 Sidewinder missile was designed for visual range combat and had a range of 2.5 miles. The USAF put their faith in guided missile technology and did not equip the F-4 Phantom with guns. The Pk (probability kill) of AIM-7 Sparrow missiles during tests was .70 but during combat the Sparrow had a Pk of .08. Thus, Vietnamese Migs were 100 times more likely to get within visual range and initiate a dogfigt than expected. (RAND, 2008)The Sidewinder did not fare much better with a combat Pk of .15. This spectacular lack of foresight lead to pilots being defenseless without any back up. As a result, pilots had gun pods attached to the F-4 latter in the war. In essence, the lesson learned was that new technology and tactics should always be used in conjunction with older proven technology and tactics in the event that Murphy's law comes to fruition.

The counter point to the argument that the F-35 needs maneuverability is that the F-35 is stealth and enemy fighters would not be able to get within visual range. This assumption is unrealistic. The F-35 will be able to destroy 4.5 generation threats from the comfort of bvr in all likelihood. However, the real threat for the F-35 is against other 5th generation stealth fighters such as the Pak Fa. Because of its stealth, the Pak Fa would not be detectable by the F-35 until it was within 30 nautical miles (estimate using frontal rcs) while the Pak Fa would detect the F-35 at 28 nautical miles. (APA, 2009)If both aircraft are speeding towards each other at mach 1.5 they would be on top of each other in just over 50 seconds. Visual range dogfights are MUCH more likely in the event the JSF is faced with a 5th generation opponent. In which case HMD technology better work. It would also not be out of the question for the Pak Fa to feature an HMD of its own, operational Mig-29's and Su-27's already do. The F-35 has the potential to win the fight but its going to be a lot closer than it needs to be. The F-22A has BOTH high maneuverability PLUS it will be upgraded with HMD technology.

A fight with the F-35 vs the Pak Fa will be close and will likely come down to the skills of their respective aircraft. There is one major component that rests in the F-35's favor and that is avionics, specifically the radar arrays. The Pak Fa is in all likelihood going to use a 1,500 TR AESA array. The new array will likely be an improvement of the NIIP Irbis-E or some evolution of the system in conjunction with other secondary radars. The Irbis-E has 1,500 TR nodes effectively meaning it has more "detection power" than the 1,200 TR F-35 AN/APG-81 AESA.  The vulnerability of the Irbis-E is compounded further by the fact that it is not a low-probability-of-intercept radar(LPIR). Russian engineers do not have a comparable the level of experience in designing LIP radar modes using emission control principles. In tests the APG-81 was able to jam and track even the LPIR of the F-22A (AN/APG-77)

In a series of tests at Edwards AFB, Calif., in 2009, Lockheed Martin’s CATbird avionics testbed—a Boeing 737 that carries the F-35 Joint Strike Fighter’s entire avionics system—engaged a mixed force of F-22s and Boeing F-15s and was able to locate and jam F-22 radars, according to researchers. - Aviation Week, 2011

If an F-22A with LPIR is vulnerable to the F-35 jamming it, essentially greatly reducing detection abilities, than the Pak Fa without LPIR is that much more vulnerable. As for vulnerability to jamming, the AN/APG-81 has an extremely high resistance to being jammed. In fact, the AN/APG-81 won the David Packard Excellence in Acquisition Award because of its performance against jamming. This ability to jam and track a Pak Fa might end up being what gives the F-35 the edge. Either way, it will be too close for comfort.

Further Reading (links)

Canada and the F-35
Murphy's Law: F-35 Development and Performance Concerns











Monday, August 1, 2011

"Hornet Buffs Up"

Check out Bill Sweetman's article on Aviation Week about new F/A-18E Super Hornet upgrades. These new upgrades include:
-enhanced Electric F414 engines with 20% more thrust
-infrared search-and-track system
-spherical-coverage missile-approach warning system
-further reduced radar cross section (before upgrade 1m^2 est)