http://www.nationalinterest.org/blog/the-buzz/does-the-us-navy-need-21st-century-f-14-tomcat-14063
Ya think? I thought this article was relevant to the discussion.
Ya think? I thought this article was relevant to the discussion.
F-14 Questions Answered - Ask Away
- Thread starter Astro14
- Start date
That's what Navy Pax River said.
In: https://apps.dtic.mil/dtic/tr/fulltext/u2/p011127.pdf
"Case in point, if the engineers think it is a
great idea to design an airplane to be flown with
"reckless" abandon by providing superior departure
resistance in the flight control system automatically,
they may actually (and probably will be) taking away
some of the tactical utility of the aircraft. There was
(and is) a lot of truth to the fighter pilots view of the
world that you have to fly "to the edge of the envelope", the point just prior to a departure, in order to maximize the effectiveness of your aircraft in combat."
Looking at what the F-14 Tomcat went through in departure spin resistance (or lack thereof...), and comparing to the F/A-18 program, gives a glimpse into the collective minds of Navy fighter pilots of the past 30 years.
Conversations I had in McDonnell-Douglas in the 1980's with Roger Berger there, and his team of flight control engineers, about the value of sideslip (beta and beta rate) feedback were doomed to collect dust as it turned out. A better presentation of the facts might have helped, looking back. Failure of the sideslip idea came in 1990, even though the Navy knew Hornets were departing, and killing pilots in some cases. The idea should have been sold, yet no sale was made until the Super Hornet program almost 10 years later. About 20 or so Hornets have been lost due to Falling Leaf (not spin departure, another crazy kind of dutch roll).
About the F/A-18 departure resistance and tactical performance colliding:
"One of the first reports that sought to improve the departure resistance of the
aircraft was released in 1990. This investigation was produced by McDonnell Douglas to
propose FCC changes in response to a Navy request to improve known Falling Leaf
departure issues with the F/A-18 B/ D aircraft. Those two-seat aircraft required
significant AOA limitations above 0.7 Mach number and still were more susceptible to
departure (NATOPS, prior to IC79). That 1990 report recommended adding sideslip and
sideslip rate feedback to FCC gains when responding to pilot roll commands. The report
was well received by the NAWCAD engineering community. However, there was
substantial resistance from F/A-18 aircrew. The pilots were concerned that increased
departure resistance would necessitate reduced high AOA maneuverability and roll
performance. NAVAIR interest in support for this program was finally withheld in 1993,
as funding was re-centered around the development of the Super Hornet Program."
F-14 Tomcats of course got somewhat saved by getting the GE F110 engines, yet earlier efforts should have solved its departure (flat spin) problems. The full story of the F-14 control system development program may resemble what the F/A-18 went through: Engineering disagreeing with pilots and project management. Myself being an engineer, I think engineers should win all those debates. Super Hornet control laws prove the compromise between departure resistance and crazy-tactical-flying can be done.
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Here is an interesting article in "The National Interest" appearing today that discusses the upcoming 6th generation fighters:
http://nationalinterest.org/blog/the-buz...inate-the-14091
And, another earlier article, 13 Oct., asking the question, "Do we need an F-14 for the 21st century?"
http://nationalinterest.org/blog/the-buzz/does-the-us-navy-need-21st-century-f-14-tomcat-14063
http://nationalinterest.org/blog/the-buz...inate-the-14091
And, another earlier article, 13 Oct., asking the question, "Do we need an F-14 for the 21st century?"
http://nationalinterest.org/blog/the-buzz/does-the-us-navy-need-21st-century-f-14-tomcat-14063
I disagree that engineers should win all the debates. You might build it, but the operational environment can only be understood by one who's been there. Further, the best employment, the tactics, for the design will determined by that operational environment, which will change with time as the adversary changes.
The F/A-18E/F (Super Hornet) has the advantage of 30 years of advances, particularly in electronics and computer processing power. The flight control system on that airplane is quite good, so I hear, but we couldn't even dream of that level of sophistication in 1967, when Grumman bid on the F-14.
Further, despite those 30 years of advances in flight controls, and propulsion, the airframe itself isn't that much better. It has a dramatically lower top speed, similar landing speed, similar high AOA limits, and similar capability in load and endurance. The weapon system benefits from the advances in processing capability...but the machine itself is frankly, inferior.
Just as big, but much slower, and not quite as long range...the F/A-18 was designed as the low end option. Cheaper, smaller, lighter. The C-Class to the S-class. We grew the C-class, but its C-class roots still show...
The F/A-18E/F (Super Hornet) has the advantage of 30 years of advances, particularly in electronics and computer processing power. The flight control system on that airplane is quite good, so I hear, but we couldn't even dream of that level of sophistication in 1967, when Grumman bid on the F-14.
Further, despite those 30 years of advances in flight controls, and propulsion, the airframe itself isn't that much better. It has a dramatically lower top speed, similar landing speed, similar high AOA limits, and similar capability in load and endurance. The weapon system benefits from the advances in processing capability...but the machine itself is frankly, inferior.
Just as big, but much slower, and not quite as long range...the F/A-18 was designed as the low end option. Cheaper, smaller, lighter. The C-Class to the S-class. We grew the C-class, but its C-class roots still show...
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When the Navy killed the NATF (Navy F-22-like program) and the A-12 (long range, stealth attack airplane), I thought Naval Aviation had reached a crossroads and has chosen irrelevance as its future...
With no ability to strike deep into a near peer nation, the Carrier would cease to be the platform of choice.
Then, oddly, we found ourselves in very permissive (low-threat) environments: Bosnia, Iraq, Afghanistan. No one needed the high-end airplane because there was no air to air threat, and little surface to air threat...so, Naval Aviation shone in providing the preponderance of close air support in Iraq and Afghanistan.
But we are now facing a difficult choice: The F-35 is the F/A-18 replacement. Much better range, but no more than the A-6 or F-14 had, and it does not have a big increase in weapons load. Airframe performance is OK, not great, certainly not in the F-22's league and now, we are stuck with the low-end airplane...and an enormously expensive one at that.
Personally, I thought that we should have gone back to Northrop when they lost the ATF competition...the YF-23 was, by all accounts, more stealthy, and much faster than the YF-22. The YF-22 was more conventional, slightly more maneuverable, and considered to be lower risk by the USAF...
Imagine that F-23 with the structural upgrades for a carrier environment...it would eat the pudgy, slow F-35 alive in an air-air engagement...and that's exactly what we need on the opening days of a conflict with a near-peer nation...
https://en.wikipedia.org/wiki/Northrop_YF-23
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Frankly, the lack of capability displayed by the F-35 and its ongoing development troubles and very high cost are enough to make one go beyond worry to outright despair.As you point out the F-18 is OK but no air superiority fighter. Taken together with the low buy on the F-22 (not to mention the B-2 and many others we need not discuss) it makes me pray they are building scads of X47B-like fighters at some hole in the wall at Groom Lake so that these few manned platforms can be "battle managers" for lack of a better term. We have been making poor national priority decisions for quite some time now. Let's hope we only appear to be incompetent.
Next "Top Gun 2" movie will address that very issue, the evolution of using more UCAVs to boost the force. Should make up for a lack of blazing Tomcat-like performance from the slower F/A-18.
My main point was that McD-D and some at NAVAIR Pax River in 1990 (or earlier) almost gave the Hornet beta and beta rate feedback, and later proved it could be done when it was finally done in 2000 on the Super Hornet, managing to preserve the tactical "pirouette" maneuver & agility while preventing departures. I've always been a little fuzzy on how the F-14 Tomcat program solved most of its dangerous tendencies, although it does look like the (too late) F110 and DFCS might have done it all.
The requirements process has to begin and end with threat analysis. What the threat can do, what the threat will do and a margin for the breakout capability the threat almost certainly is working on. While the engineers have to design the metal it can only be at the behest of those who both face and define the threat. It is a hand in glove process. Both the hand (user community) and the glove (design community) have to work together but it is the hand that moves the glove. The real problems arise when the requirements process is subverted due to political, budgetary and technology constraints but, unfortunately, that is the real world. Most of us have grimly smiled (or spit) when some dunderhead who looked good in a suit and had a million dollar smile made Captain or Flag and they sent him off to DC but sometimes it is exactly those guys who work those dark but very necessary corridors of politics best. The rest of us usually don't have the patience. But that's another part of the story.
The requirements process begins with mission analysis, defined by national strategy and objectives. Required capabilities are determined, and gaps in those capabilities identified. Integrated solutions are developed across Doctrine, Organization, Training, Materiel, Leadership, Personnel and Facilities...
At least, that is the JCIDS architecture...airplane acquisition falls into Materiel, but the capability that they are built to provide has to be integrated into the other elements of the solution.
Unfortunately, as you've said, politics enters into it. Many in senior leadership, including political leadership, understand only platforms, because materiel has the biggest price tag/cost, and then fail to understand the integrated nature of capability development...and then, you have "desirement" replacing "requirement".
But the F-14 had a specific set of requirements that it met with spectacular success....despite the budget and political battles it faced...
At least, that is the JCIDS architecture...airplane acquisition falls into Materiel, but the capability that they are built to provide has to be integrated into the other elements of the solution.
Unfortunately, as you've said, politics enters into it. Many in senior leadership, including political leadership, understand only platforms, because materiel has the biggest price tag/cost, and then fail to understand the integrated nature of capability development...and then, you have "desirement" replacing "requirement".
But the F-14 had a specific set of requirements that it met with spectacular success....despite the budget and political battles it faced...
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No argument from me. I defer to you for the wording. I would point out though that in a world with no threats none of those things would be needed. Threat drives those other processes at least in this context. My other point was probably in agreement with your earlier post that in hierarchy the users should lead in development requirements. I would go so far as to say that the combatant commander should have final say, below national level, if the requirements are or are not being met. If they are not then why spend the money to be a speedbump (unless that is the unfortunate strategy)? Engineering should not. And, yes, it all came together brilliantly in the F-14 even with some of the limitations you have spoken of. Where do you feel the F-35 process broke down, not the aircraft, the process?
By designing the F35 in away that it's elligible for export and by definition inferior to the F-22.
Excellent point. Then they try to ensure its success by setting up a multinational program office - makes it harder to kill politically but also provides a reason for pressing on when it might should have died if it no longer made technical sense. There have been some successes like that though including the F16 and MLRS. Give the devil his due.
Maybe add the many versions and the compromises that have to be made because of that. "Multi-mission" seems to happen more than it should and makes a system start out with one foot in the grave so to speak.
I have to say I'm just as guilty as the next dreamer when it comes to more versions. I look at that drive shaft mechanism of the lift fan variant and wonder how big a generator I could stuff in there for a 100-200+ kilowatt laser. /forums/graemlins/grin.gif Then we would have our fleet defense fighter ala F14 to knock down clouds of cruise missiles. See how easy mission creep is?
Development of modified versions of the F-14 from about 1978 to the present could have replaced ALL those F/A-18's, Prowlers, A-7's. Similar to what was done to upgrade/evolve/develop the AV-8B Harrier II in the early '80's from the old AV-8A design: Replaced forward fuselage and wing with all-composites, new flight controls, new cockpit, new computers....
https://en.wikipedia.org/wiki/McDonnell_Douglas_AV-8B_Harrier_II http://link.springer.com/chapter/10.1007%2F978-1-4684-1033-4_4
That way, over a period of years between 1980-1990-2000, we could have become an all-F-14 fleet using modular avionics and more composite parts, cockpit upgrades, modeled loosely on the AV-8B upgrade program.
On any given day on an aircraft carrier, each F-14 would get the weapons and computer boxes it needed to be air superiority or ground attack or recon and yes even a Growler version like they are doing now with the F/A-18G.
You could even be politically correct with this, giving McDonnell-Douglas responsibility for hydraulic reliability improvements, testing, composite part design, etc. to share the congressional districts participation.
Then let DARPA and NASA keep research prototypes going for 2020 and a stealthy platform.
Think about it: We could keep the AIM-54 Phoenix system and modularize the WSC's to accept BombCat swap-outs on days when called for.
https://en.wikipedia.org/wiki/McDonnell_Douglas_AV-8B_Harrier_II http://link.springer.com/chapter/10.1007%2F978-1-4684-1033-4_4
That way, over a period of years between 1980-1990-2000, we could have become an all-F-14 fleet using modular avionics and more composite parts, cockpit upgrades, modeled loosely on the AV-8B upgrade program.
On any given day on an aircraft carrier, each F-14 would get the weapons and computer boxes it needed to be air superiority or ground attack or recon and yes even a Growler version like they are doing now with the F/A-18G.
You could even be politically correct with this, giving McDonnell-Douglas responsibility for hydraulic reliability improvements, testing, composite part design, etc. to share the congressional districts participation.
Then let DARPA and NASA keep research prototypes going for 2020 and a stealthy platform.
Think about it: We could keep the AIM-54 Phoenix system and modularize the WSC's to accept BombCat swap-outs on days when called for.
This article today doesn't state the possible power of a small airborne laser (that's not the point of this development) but it gives a good indication of how close we are to an air to air combat revolution.
http://www.dailymail.co.uk/sciencetech/a...ghter-jets.html
Hey Astro14
Do you have any opinion on the F-14 losing its pop-out forward leading edge root extensions? I heard they stopped using those at some point.
Do you have any opinion on the F-14 losing its pop-out forward leading edge root extensions? I heard they stopped using those at some point.
The glove vanes, as they were known, had two design purposes:
1. Move the center of pressure forward during high speed flight, thus reducing trim drag and increasing top speed. The CADC programmed them out at 1.35 IMN, with full extension at 1.45 IMN (that function was checked on a post maintenance check flight).
2. Move the center of pressure forward and increase stability, while reducing loads on the horizontal tails during air - ground delivery. Select "bomb" mode on the wing sweep switch (inboard throttle) and out come the glove vanes.
Plus they looked really cool...
The F-14 B/D were delivered without glove vanes. The thinking was that:
1. The increased power of the F-110 would overcome the drag (and it did...up to about 1.6 IMN... When the mass flow and compression ratios became an issue). Note: the highest I've been was in a -B, extra power matters. The fastest I've been was in a -A. Drag and mass flow through the engine matters.
2. We found, through testing, that you could bomb with the wings in auto and not affect accuracy. This gave a post-delivery maneuver advantage - the pilot could begin immediate maneuvering without having to select wings back to auto.
After a decade of the B/D in service - the vanes were simply removed from the A to save maintenance costs, we were told. But it cost money to remove them. I think it had more to do with parts inventory cost...they never broke or leaked that I knew of. Super simple construction.
And yes, I mourned their loss...there was something about the look of the airplane with them extended that I really liked. I put them out in the break every chance I could...
1. Move the center of pressure forward during high speed flight, thus reducing trim drag and increasing top speed. The CADC programmed them out at 1.35 IMN, with full extension at 1.45 IMN (that function was checked on a post maintenance check flight).
2. Move the center of pressure forward and increase stability, while reducing loads on the horizontal tails during air - ground delivery. Select "bomb" mode on the wing sweep switch (inboard throttle) and out come the glove vanes.
Plus they looked really cool...
The F-14 B/D were delivered without glove vanes. The thinking was that:
1. The increased power of the F-110 would overcome the drag (and it did...up to about 1.6 IMN... When the mass flow and compression ratios became an issue). Note: the highest I've been was in a -B, extra power matters. The fastest I've been was in a -A. Drag and mass flow through the engine matters.
2. We found, through testing, that you could bomb with the wings in auto and not affect accuracy. This gave a post-delivery maneuver advantage - the pilot could begin immediate maneuvering without having to select wings back to auto.
After a decade of the B/D in service - the vanes were simply removed from the A to save maintenance costs, we were told. But it cost money to remove them. I think it had more to do with parts inventory cost...they never broke or leaked that I knew of. Super simple construction.
And yes, I mourned their loss...there was something about the look of the airplane with them extended that I really liked. I put them out in the break every chance I could...
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Another cool insider answer! The more we learn about the -14, the more we like that aluminum flying enforcer....
For those reading this, note center-of-pressure (cp) naturally moves aft as speed goes supersonic. The tail then has to push down harder to keep the nose up (trimmed). In this airplane, like most of them, the center-of-gravity (cg) is always forward of the cp, yet you don't want the cg to be too far in front of the cp or the tail has to push down too hard.
That fact has me confused. The glove vanes move cp forward, granted, which technically reduces static stability from the too-stable supersonic condition. So are you really saying the glove vanes reduced trim alpha, making bomb separation more clean?
I see the glove vanes as fuel saving in cruise, since when deployed, trim drag goes down slightly. As a flight control law engineer, I'd automatically want to retract them if pitch rate was greater than 20 deg/s and alpha >70% stall in cruise for safety.
For those reading this, note center-of-pressure (cp) naturally moves aft as speed goes supersonic. The tail then has to push down harder to keep the nose up (trimmed). In this airplane, like most of them, the center-of-gravity (cg) is always forward of the cp, yet you don't want the cg to be too far in front of the cp or the tail has to push down too hard.
That fact has me confused. The glove vanes move cp forward, granted, which technically reduces static stability from the too-stable supersonic condition. So are you really saying the glove vanes reduced trim alpha, making bomb separation more clean?
I see the glove vanes as fuel saving in cruise, since when deployed, trim drag goes down slightly. As a flight control law engineer, I'd automatically want to retract them if pitch rate was greater than 20 deg/s and alpha >70% stall in cruise for safety.
Ah...I thought I had mentioned it before, perhaps not.
Selection of bomb mode puts the wings at 55 degrees of sweep, glove vanes out in the -A. It was thought that the fixed sweep would make for a more stable platform. And that sweep would allow pretty high (though not supersonic) speeds.
If the wings were aft of 55 when bomb mode was selected, they would stay there and not move until returned to auto or manual forward sweep (thumbswitch) was selected.
That help?
As far as alpha, bomb delivery (in the old days of dumb bombs) was done in a dive at relatively high speed. The alpha was quite low, regardless of wing position.
Further, the tunnel created some interesting aero effects, and the Tomcat needed a strong ejection charge to get the bomb clear of the tunnel...when we first started carrying bombs again in 1990...we had to go through a lot of testing with our new racks, to ensure that the weapons would clear...
Selection of bomb mode puts the wings at 55 degrees of sweep, glove vanes out in the -A. It was thought that the fixed sweep would make for a more stable platform. And that sweep would allow pretty high (though not supersonic) speeds.
If the wings were aft of 55 when bomb mode was selected, they would stay there and not move until returned to auto or manual forward sweep (thumbswitch) was selected.
That help?
As far as alpha, bomb delivery (in the old days of dumb bombs) was done in a dive at relatively high speed. The alpha was quite low, regardless of wing position.
Further, the tunnel created some interesting aero effects, and the Tomcat needed a strong ejection charge to get the bomb clear of the tunnel...when we first started carrying bombs again in 1990...we had to go through a lot of testing with our new racks, to ensure that the weapons would clear...
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Astro14, yet just to be clear, glove vanes reduce stability, not increase stability (cp moves forward toward cg). I see your point though, as 55 sweep moves cp too far back so glove vanes just move it forward only a little, still plenty of stability.
On "stores separation", pulling slight g's or diving in straight, the important thing is to get as low an alpha and/or high g's on the stores to make sure they don't float back up to the wing at separation.
On "stores separation", pulling slight g's or diving in straight, the important thing is to get as low an alpha and/or high g's on the stores to make sure they don't float back up to the wing at separation.
