F-14D Tomcat vs. F/18 E/F Super Hornet
Flight Journal Magazine ^ | February 2002 Issue | Bob Kress and RADM Gilchrist USN (Ret)
Posted on Friday, December 21, 2001 10:30:45 PM by LSUfan
Editors Note: Every airplane that goes into service is accompanied by controversy. This is especially true of the F/A-18E/F Super Hornet. Our two experts argue that the Super Hornet is not necessarily the airplane the Navy needs for the future, and their backgrounds lend weight to their arguments. Rear Admiral Paul Gillcrist U.S. Navy (Ret.) spent 33 years as a fighter jet pilot and wing commander and was operations commander for all Pacific Fleet fighters. Bob Kress is an aeronautical engineer and, during his long career at Grumman, he was directly involved in the development of the F-14 Tomcat. Their analysis makes an interesting statement when placed against the background of the war on terrorism.
The requirement for a practical deep interdiction fighter/bomber have long been the subject of controversy within the naval aviation community, especially when it comes to the F-14D Tomcat versus the F/A-18E/F Super Hornet. Often, however, the definition of deep interdiction is changed to fit the aircraft carrier under discussion, rather than taking into account the real-world theater of operations for which it is destined.
Events over Afghanistan, however, have forced us to formalize what is really needed if an aircraft is to strike an enemy deep within its country. Today, we know that the politics of surrounding countries can dictate mission distances that stretch the ability of current aircraft to their limits. The U.S. relies on Navy aircraft carriers as bases. So, when putting fighter/bombers over Afghan targets, which aircraft led the charge? the tried-and-true F-14D Tomcat with the F/A-18 Hornet well behind.
This particular conflict motivated us to address what we see as a serious problem concerning Naval aviation assets and the realities of the fields over which we will fight.
As shown over Afghanistan, there are four basic requirements of any carrier strike force:
Reach the target
Dont get shot down by SAMs, AAA, or enemy fighters
Strike the target
Return to the carrier before running out of gas
Within these four seemingly simple rules are the needs for an airplane to have a long range while carrying sufficient munitions to hammer a target and still be able to fight its way through enemy aircraft and AAA threats.
An Afghanistan Scenario
Because our government isnt telling us all its secrets, well have to make some assumptions when using Afghanistan as an example. It is, however, obvious that reaching the target presents a great challenge. To avoid Silkworm-class missiles, the carrier battle group probably would not want to venture north of a line joining Masqat, Oman and Ahmadabad, Pakistan. Along this line, the group would be somewhat west of Karachi. Reaching Kabul would require a one-way flight of roughly 825 statute miles. Assuming the use of S-3 tankers, an F-14D strike, refueling somewhere between Quetta and Sukkur, Pakistan, wouldnt have any trouble attacking targets in the northernmost parts of Afghanistan. If, however, an F/A-18E/F refuels in the same spot, it will barely make it to Kabul. The un-refueled radius of an F-14D carrying the normal strike load (four 2,000 pound LGBs, two Phoenix missiles, and two Sidewinders, plus 675 roundsof 20mm, and two, 280 gallon external tanks) is at least 500 statute miles.
Accompanying E/F Super Hornets have only a 350-statute-mile radius carrying about half the bomb load. To complete the picture of mission distances, the S-3s would have to dash back to the CVs, hot-refuel, and meet the raid coming out of Afghanistan, which would be much in need of JP-4 cocktails.
Why are we nit picking over mission details? Easy! At the beginning of the studies that led to this article, we were convinced that the Afghan campaign would be an all-USAF show, and that would lead to questions of carrier-fleet effectiveness. But map studies combined with knowledge of geopolitical restrictions showed that carrier assets, primarily the F-14D, were just about the U.S.s only option. This has clearly been substantiated by events.
Of course, the F-14Ds were not the first to hit targets in Afghanistan; b-2 stealth bombers each carried 16, 2,000-pound GPS-guided bombs. The flew from Whiteman AFB in Missouri a 33-hour round trip. Further, big-time USAF strategic air assets B-52s and B-1s arrived shortly afterward.
It was soon apparent that USAF tactical aircraft were not being used in Afghanistan. We found that, even given unlimited in-flight tanker refueling, the USAF F-15 and F-16 could not be used without a Middle Eastern ground base. Turkish bases were simply too far away and would require refueling over hostile areas. Only the use of tactical air bases in Turkmenistan and/or Uzbekistan would work, and this would allow only partial coverage of Afghanistan.
The big question becomes: does the Navy have the assets to able to carry this kind of war into the future, and what kind of planning is in place? To cut to the chase, the discussion once again reverts to whether or not the new Super Hornet will really cut the mustard or the Navy has taken yet another wrong turn that will cost us dearly on the battlefield.
A History of Naval Aviation Difficulties
The subject of the erosion of Naval aviation has nagged both of us ever since the cancellation of the A-12 program by the Secretary of Defense in the late 80s. It was a watershed for a number of reasons, not the least of which was a level of bad management that hadnt been seen in the Pentagon for decades! We can look back on that day and clearly see that the unraveling of the fabric of Naval aviation would become a long-term trend. Neither of us contends that the A-12, as envisioned by Navy leaders, was the right airplane to develop at that point in history; in fact, it wasnt! That, however, is another story for another time.
We have to put off writing this article simply because we know it is likely to ruffle many feathers in the Pentagon and on Capitol Hill, but events in Afghanistan again brought our main arguments into focus. Is writing this kind of article worth it, we wondered; we might be seen to be piling it on when the Navy is in difficulty and clearly on a steep, downhill slide. Well, we have listened, with no small restraint, to the pontifications that justify how well the Navy is doing with its favorite program, the F/A-18E/F Super Hornet despite unimpeachable reports to the contrary from the guys in the fleet; comments made to us by young fleet pilots who have flown the airplane and describe it as a dog carry much more weight with us than statements from senior officers and civilians higher in the food chain. But certain pontifications in a statement by a senior Naval officer who should have known better served as the last straw.
The pronouncement appeared along with a spate of triumphal announcements that celebrated the successful completion of the Super Hornets first operational evaluation (OPEVAL). In a publication called Inside Washington, the Navys director of operational testing is quoted as saying that the Super Hornet was superior to its earlier models
in every category but three: acceleration, maximum speed and sustained turning performance. This pronouncement boggled our minds because these are the very performance capabilities that determine a tactical airplanes survival. Then, as if to justify this hand grenade, the officer is quoted as stating that the Navy has sacrificed speed in the Super Hornet for other beneficial capabilities, and he asserts, brute speed is no longer the discriminator it once was when the benchmark was the Soviet threat. It is clear that this Naval officer doesnt have a clue about aerial combat and the importance of total energy in the complex equation of energy maneuverability. Nor does he seem to understand that Third World countries all around the globe are purchasing the very latest operational Russian-built fighters that are also licensed for production in China. The Russian aerial threat still exists; what has changed is that the pilots arent Russians.
As a nation, we have always had the means to protect our own global interests as well as those of other countries. Short of nuclear war, the carrier battle groups have been able to strike on very short notice. A Presidents first question in time of crisis is often, Where are the carriers?
F-14Ds Carry a Major Punch
With a layered defense, including air assets, guided-missile cruisers and frigates and undersea backing, the carrier battle groups are pretty well invulnerable. On the longer Nimitz-class carrier, we see the F14D a truly long-range fighter/bomber plus lightweight F/A-18A fighter/bombers. The long-range A-6 bomber has gone forever, but its derivative, the EA-6B Electronic Warfare (EW) aircraft is in place and is in much demand by both the USN and the USAF. This countrys Desert Fox and Kosovo experiences have, at last and correctly shifted the focus away from stealth and toward electronic warfare. We will have more to say on this important topic in a subsequent article. In short, at the moment, the deck complement looks adequate. The F-14D can pick up the A-6 role because it was designed to do so from scratch. Its performance in Kosovo as a very effective strike leader has more than borne out that fact. With LANTIRN, night-vision devices and synthetic aperture A/G radar, the F-14 targeted not only its own four 2,000-pound weapons but also the ordinance of the F/A-18s, which dont have such capable sensors.
An interesting comparison can be made to quantify the F-14Ds strike effectiveness. Compare one F-14D and one B-2 bomber during a two-night (33-hour) mission in Kosovo. In reactive situations (no foreign base), the B-2 operates from the U.S. (lack of overseas B-2 basing is a serious constraint and there are only a limited number of B-2s to begin with). The chart shows the weapons delivered U.S. to Kosovo and back for the B-2 and the F-14D.
33-HOUR-MISSION STRIKE EFFECTIVENESS
B-2 F-14D
No. of 2,000 lb. Bombs
20*
.. 4
Mission time (hours)
33**
3+
No. of missions
1 ..
5***
No. of bombs delivered
... 20
.. 20
First bombs on target (hours)
.. 17.5
.. Approx. 2
Notes: * Av. Week 1/17/00; 40,000lb payload
** From Whiteman AFB, Missouri
*** All-night missions
The F-14D information is from Desert Fox operations
Carrier Effectiveness is the Issue
This simple chart says a great deal about a carrier battle groups effectiveness. Remember that there are or there can be 24 F-14Ds on a ship such as the John C. Stennis (CVN-71). Twenty four F-14Ds can deliver more weapons than the entire 16 aircraft of a B-2 fleet. Unfortunately, the numbers of F-14Ds are dwindling, and they will be almost gone in another 10 years. What will be the replacement?
The F-14D will be replaced by the F/A-18E Super Hornet, which attempts deep-interdiction missions. Though its a whizzy little airshow performer with a nice, modern cockpit, it has only 36 percent of the F-14Ds payload/range capability. The F/A-18E Super Hornet has been improved but still has, at best, 50 percent of the F-14Ds capability to deliver a fixed number of bombs (in pounds) on target. This naturally means that the carrier radius of influence drops to 50 percent of what it would have been with the same number of F-14Ds. As a result, the area of influence (not radius) drops 23 percent! No wonder the USN is working on buddy tanker versions of the Super Hornet.
By the way, now that the A-6 tanker has gone, how will the Hornets get to deep-interdiction targets?
Contrary to what were officially told, a tanker variety of the Hornet is simply not the answer. In an attempt to make it supersonic, the F-18E has been given a low aspect ratio and a razor blade of a wing. This hurts subsonic drag and carrier takeoff payload when compared with the KA-6 tanker, which is an aerodynamically efficient solution. Equally silly is the proposal for an EW version of the F-18E. The same aerodynamic reasons apply for this airplane, plus it has an external stores dilemma. To get sufficient range to support a deep-interdiction mission, the EF-18E would have to use up precious external store stations with fuel tanks rather than ECM pods as carried on the EA-6B. Perhaps the Navy should consider putting the EA-6B back into upgraded and modernized production and build some of them as tankers?
As this is being written, it is too early to comment in an informed manner on the war on terrorism in Afghanistan. The USAF heavy bomber raids are fully public. However, it is evident that USN carrier strike groups that consist of F-14Ds and F-18s are conducting the tactical raids. A study of maps shows that CVN airborne S-3 tankers facilitate the conduct of these raids by refueling, probably over Pakistan. At this time, USAF tactical air assets do not have bases close enough to Afghanistan to allow airborne refueling over friendly nations. By the time this finds its way into print, that may have changed.
Reported Super Hornet Problems
Although the Navy has been working very hard to correct F/A-18E/F OPEVAL problems, it is worth summing them up: the production of the F/A-18E/F is significantly overweight with respect to its specifications (30,000 pounds empty weight). This is far in excess of what one would expect for a variant of an existing F/A-18 A, B, C, or D. Aircraft weight estimation methods could, and should, have been much better; in fact, when we look objectively at the F/A-28E/F, we see an airplane with a brand-new wing, new fuselage and new empennage in other words, a new airplane. This is, therefore, what Congress would call a new start. Both Congress and the Department of Defense (DOD) had to be looking the other way when the Navy was permitted to slip this airplane by as a simple modification of an existing airplane.
In combat-maneuvering flight, the aircraft had severe wing-drop problems that defied resolution, despite the use of every aerodynamic analytical tool available. Eventually, one test pilot cam up with a leaky-fold-joint fix that opened chordwise air slots to aspirate the wings upper surface flow and thereby prevent the sharp stalling of one wing before the other. The stalled more or less together, but much easier and more severely than before. This new fix is what the aerodynamicists call a band aid. It causes aircraft buffeting, which is generally a source of wing drag. But a fix that combined acceptable wing drop with acceptable buffeting had been achieved. One test pilot commented dryly, Id like the buffeting levels to be a little lower so I could read the heads-up display!
Owing to its high drag and weight (and probably other factors), the F/A-18E is significantly poorer in acceleration than the F/A-18A. Also, its combat ceiling is substantially lower, and its transonic drag rise is very high. We have stayed in touch with some pilots at the Navys test center and have gathered some mind boggling anecdotal information. Here are some examples:
An F/A-18A was used to chase an F-14D test flight. The F-14D was carrying four 2,000-pound bombs, two 280-gallon drop tanks, two Phoenix missiles and two Sidewinder air-to-air missiles. The chase airplane was in a relatively clean configuration with only a centerline fuel tank. At the end of each test flight, the chase airplane was several miles behind the test airplane when the chase airplane reached bingo fuel and had to return to base.
An F/A-18E Super Hornet is tested using the same chase airplane, an earlier model Hornet, in the same configuration. The chase airplane does not need full thrust to stay with the test airplane.
An F/A-18E/F in maximum afterburner thrust cannot exceed Mach 1.0 in level flight below 10,000 feet even when it is in the clean configuration (no external stores). At 10,000 feet, the F-14D can exceed Mach 1.6.
A quote from a Hornet pilot is devastatingly frank: The aircraft is slower than most fighters fielded since the early 1960s.
The most devastating comment came from a Hornet pilot who flew numerous side-by-side comparison flights with F/A-18E/F Super Hornets and says: We outran them, we out-flew them and we ran them out of gas. I was embarrassed for them.
Updating the F-14
In the January 1991 issue of Naval Aviation, an article reminded us of some history: After the dive/bomber became a naval aircraft type in the mid-1930s, fighters were designed primarily as gun platforms. However, the strength and power that characterized the F4U and F6F enabled them to be readily modified to fighter/bombers. Each could carry forward-firing rockets, two 1,000 pound bombs or a droppable fuel tank. The proportion of fighters assigned to fast carriers increased steadily from 25 percent of complement in 1942 to 50 percent in 1944 to 70 percent in 1945. The dual role made this great increase in air-to-air combat power possible with little loss in air-to-surface capability.
How about a Hellcat II, aka Tomcat II? The first order of business would be to resurrect as many retired F-14s (of any configuration) as we can. Second, combine these with fleet F-14As, the remaining F-14As and even the Iranian F-14 assets that might be obtainable (Iran took delivery of approximately 80 F-14s under the Shah; about 30 are still airworthy). Third, design a program to upgrade all of these aircraft for F-14Ds. This may sound wild, but Grumman experience in restoring Malaysian A4D basket cases to mind condition in the 80s was very successful, and they were not even Grumman airplanes! Similar success in restoring fleet A-6s at Grummans St. Augustine, Florida, facility was achieved. It would appropriate for the Navy or DoD to launch a study by a blue ribbon team under aegis of NAVAIR. We estimate that about 200 additional F-14s could be brought back into the fleet. The titanium box beams and bulkheads are nearly indestructible as well as reparable using electron-beam welding; but this is not yet a Tomcat II.
Buying time with these programs would allow the convening of a design team again led by NAVAIR of contractor personnel, MIT scientists and other university help to study the cost of building new F-14s. We think the following design changes to the F-14D are achievable for a new baseline airplane and later for block change improvements:
1. Increase high-value-weapon bring-back capability; this would mean that the F-14D, carrying heavy stores, would hit the arresting gear too fast. We could conclude that a bigger wing with more powerful high-lift flaps and slats is required, but fly-by-wire systems allow a more elegant solution.
2. With flaps down, the basic F-14 needs a down tail load to trim out the flap nose-down pitching moment. Allowing the aircraft to fly slightly unstable in pitch, now enabled by fly-by-wire technology, suggests the use of a canard, which would produce uploads and relieve the down tail loads.
3. The net result of these changes is that an increase of 4,500 pounds in bring-back store weight could be allowed; this is equivalent to a decrease in approach speed of 12 knots. The relief of down tail loads also solves an aft fuselage maneuvering fatigue problem and brings an air combat maneuvering lift increase by 19 percent. Turning (lift to drag) is also improved by relieving down tail loads. This change could be readily achieved because no primary structure is involved. A further plus of this design change would be that the aircrafts internal fuel capacity could be increased by several thousand pounds.
4. We appreciate the value of staying with a variable-sweep design especially for the podded, twin-engine F-14. First, we could have a carrier aircraft with landing speeds in the order of 130 knots versus the F-4 Phantom at 145 knots. At the other end, the mission payload/range is greatly increased by flying unswept, as is air combat maneuvering. Why the latter? Because dedicated air combat occurs at below about 0.8 because of high turning drag an arena in which the F-14s 20-degree sweep is optimal. And, of course, the F-14 has been to Mach 2.51 with four Sparrows loaded at 68 degrees of wing sweep. It has flown to Mach 1.35 at 5,000 feet (813 knots IAS), at which point the throttle had to be retarded to avoid over-speed.
5. [At this point, the article jumps to what should be #5 in this list. It continues
]
be redesigned to cope with the level of instability induced by the larger glove, which is minus fiver percent in clean flight and minus 13 percent flaps down at the most aft CG. This is no big deal and, in fact, it may be within the capability of the existing F-14D bobweight system that tolerates some longitudinal instability. For reference, the Grumman X-29 was 45 percent instable!
6. The F-14D should have some reasonable stealth-enhancing additions sensible stealth as we used to call it which would have practically no impact on weight or performance! A lot of work was done to this end in around 1990; it included full-scale tests on real F-14s. Some radar signature experts know exactly what should be done. Comparing the basic radar signatures, the F-14 has a slight fundamental disadvantage: it is larger. Its tunnel mounted attack stores make, however, virtually no contribution to its signature, and it does not carry a forest of wing tanks and weapons on long-range strike missions (this also keeps its signature down).
The baseline F-14D production aircraft defined above would allow these carefully considered modifications:
1. The installation of the F-119 or the F-120 engines. The F-119 has already been checked for fit. Upgrades of the GE F-110 might also be viable. The objective would be a 40,000-pound class turbofan.
2. The installation of two-axis, vectorable, axially symmetric engine nozzles for super augmented pitch, roll and yaw control.
3. The installation of UHF antennas that would be embedded in the increased-chord leading-edge slats to allow onboard detection and tracking of stealthy adversaries. Low-frequency radar works well against low-radar-cross-section objects. Arrays like this were tested at Grumman in around 1990.
In 1990, Grumman defined many versions of what it thought the F-14D could be. It was somewhat overdone in the stealth arena, but it incorporates most of the aforementioned ideas with very little design change or combat penalty. All the changes are cosmetic tin and not basic to the structure.
A Word on Aircraft Design
Just as commercial airlines are reaching their design limitations as fighter designs have matured, they, too, have encountered the limits imposed by the laws of physics. Fighters and airliners are in the same situation, but fighters include a couple of extra dimensions. For instance, a choice has to be made between supersonic flight and subsonic combat maneuvering and cruise efficiency. The same is true of stealth versus electronic warfare. Pick one and design toward it. If you want a V/STOL, design one, but dont try to make it into a tri-service fighter/bomber.
If you want a long-lasting, long-range fighter/bomber, design it from scratch for the mission as a new or upgraded design preferably the latter. Then equip it with modern weapons, sensors, surveillance, communications and EW. Let the sensors and computers on board and remote give the crew complete knowledge of the situation in the volume of air they are trying to dominate also, and suggest the best plays. The electronics will continue to advance rapidly to provide capabilities that are now only dimly perceived, but the basic airplane, regardless of who designs it, is quickly approaching the best that it can be. In the meantime, remember to give the crew IR missiles and a Gatlin gun for those times at which Murphy intervenes and high-tech warfare once again deteriorates to the usual groveling dogfight.
The bottom line is that, unless aircraft like the F-14D continue to be on board, U.S. Navy aircraft carriers on their flight decks, and most of those will be deployed with a few aircraft on their flight decks, and most of those will be versions of the Hornet and the Super Hornet. Despite all protests to the contrary, with regard to standoff munitions and precision guided weapons, our carrier battle forces will not have the pulverizing power of their 1980s counterparts. When that time arrives, it will be the beginning of the end for carrier forces as we know them today and the end of their rapid availability to the President in times of need.
The future of NAVAIR
In 1975, an A-7 Corsair II was mounted on a pedestal outside the now closed Navy Master Jet Base, Cecil Field, Florida. On the base of the pedestal was a large bronze plaque bearing the inscription: The main battery of the fleet. The battle groups in those days equipped with Corsair Iis and A-6 Intruders could truly kick *** and take names. Those days may be over probably forever unless strong USN action is taken. We can learn major lessons from our past. Lets hope the Navy and the politicians remember to apply these lessons to the future. So Mr. President, ask not what your carriers can do for you, but what you can do for your carriers.
isnt it?
