Friday, August 5, 2016

Maintenance Upgrades

One of the most common justifications for a new design aircraft is that the existing one is too maintenance intensive (even though it was undoubtedly considered a vast maintenance improvement over its predecessor!).  Consider the F-14 Tomcat and its replacement, the F-18 Hornet.  No one had any real performance issues with the F-14 Tomcat but it was considered to be too maintenance intensive.  The F-35 was going to be a huge improvement in ease of maintenance over the F-18 Hornet (hasn’t happened but that was a major part of the justification).  And so on.

What I’ve never seen discussed or considered is the concept of a maintenance upgrade instead of a new design.  If you have an aircraft whose performance is satisfactory, why not just upgrade the maintainability?  The systems that are considered high maintenance can be stripped out of the aircraft and replaced with whatever you were going to put in the new design.

Strip out the high maintenance components and systems and rebuild the aircraft with low maintenance components and systems.  A good time to do this would be as the aircraft cycle through depot level maintenance availabilities.  Consider what we’re doing to the Hornet to extend its life.  We’re completely replacing the center barrel section of the aircraft among other major changes.  Surely, we could perform maintenance upgrades!

Yes, it would be costly to strip out electronics, pneumatics, hydraulics, piping and tubing, etc.  It would cost millions per aircraft but that’s hugely cheaper than hundreds of millions for a new aircraft.

Consider, again, the Tomcat.  Compared to its successor, the Hornet, it had superior range, endurance, speed, more weapon hardpoints, greater weapons payload, better sensors, and was, purportedly, a better bomber in its Bombcat guise.  The Hornet was less maintenance intensive and, let’s be honest, the Hornet’s main attribute was that it would ensure continued budget for the Navy.

What attributes is the Navy looking for in an aircraft, now?  Why it’s range, speed, endurance, payload, and sensors.  Hmmm …….

Of course, you can’t upgrade forever.  The F4F Wildcat was a fine aircraft but we couldn’t have upgraded it forever and still be flying Wildcats today.  At some point, the basic airframe is simply no longer viable.  However, that point is well beyond where the Navy thinks it is.  The F-14 Tomcat could have been upgraded for improved maintenance, sensors, and engines and the entire Hornet family could have been skipped.  In the time it took, and the money it cost, to progress through the Hornet generation, the Navy could have taken its time and developed a successor to the Tomcat that would have incorporated stealth and whatever other functions were desired and that successor could be entering service now, fully tested, debugged, and combat ready.


F-14 Bombcat - Skip the Hornet?


We look fondly on the Hornet when we compare it to the F-35 but we forget that the Hornet is ill-suited to the Navy’s actual operational needs – and I’m being polite about the ill-suited part.  The Hornet is a huge failure by any standard other than comparison to the F-35 which speaks more to the magnitude of the F-35’s failings than any strengths of the Hornet.

I’ve used aircraft examples but the concept of maintenance upgrades applies even more to ships due to their extreme cost.  The Tarawa class could have been easily maintenance upgraded (I’ve never really heard a good reason for their retirement).  Ships are often described by the Navy as being worn out.  That’s just another way of saying that the mechanical systems have been neglected.  Navy leadership should be fired for not conducting proper maintenance but, even so, the ship’s systems can be removed and replaced for much less than the cost of a new ship class.

Before we toss the next aircraft or ship into the dustbin, let’s think about maintenance upgrades if the platform is still capable of acceptable performance.

58 comments:

  1. The APG-79 radar for the F/A-18E/F/G and the EPE engine (F404-GE-402) for the F/A-18C/D were both partly sold on the basis of improved R&m. I'm sure there are many, many more.

    Calling the F/A-18 a huge failure is just ignorant. F-14s proved unaffordable, the A-12 died before birth, the F/A-18 replaced the A-7 and the A-4 in the light attack role and provided huge bag for the buck like the F-16 did for the USAF. When the A-12 died, the E/F affordably saved Navy TACAIR. Now when you look at the state of the Air Force and the Navy airpower, you can see the Navy's investment in the E/F has been a huge success.
    That said I think we will need something better than F-35C in 2025+ to deal with the future threats and the distances we are likely to have to deal with. F/A-XX needs to be this new capability and it needs to have longer range/endurance, more loadout, better intercept capability to reach threats before they launch, and the ability to dominate the sky. The question is can we afford that capability and is the USN too traumatized by the F-35 to actually go for that much capability?

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    1. "... you can see the Navy's investment in the E/F has been a huge success."

      No. It has been a "success" only because we didn't opt to go down the F-14 upgrade path and skip the Hornet completely and because the F-35 has been such a huge failure, thus far. You're calling it a success only because of the other failed paths, not because it was the right way to go. It was not the right way to go and has led the Navy to having air wings that are now too short ranged for today's high end combat.

      You kind of missed the point of the post!

      Keep the discussion respectful.

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    2. http://foxtrotalpha.jalopnik.com/top-gun-day-special-the-super-tomcat-that-was-never-bu-1575814142

      "The Super Tomcat 21 would be a modification of the original F-14 design and it was to feature GE-F110-129 motors that would allow the Tomcat to super-cruise (achieve mach 1+ without using afterburner) continuously at mach 1.3. Additionally, the jet would have an upgraded APG-71 radar, modified and enlarged control surfaces, and enlarged leading edge root extensions (LERX) that would house more fuel and enhance the jet's low speed handling capabilities."

      A Tomcat with the ability to go trans-sonic without afterburner, greater range, and better manueverability.

      We could have had our own version of the SU-27. Had we gone this route, I believe the CVN's would be much better off now. To paraphrase another article; CVN's are just airports. Its the airwing that matters.

      And an airwing made up of SuperTomcat 21's would have better range and speed.

      And I totally 100% agree on the maintainability upgrade. In anything you build you can make modifications based on real world data. Is that circuit board continually failing? Find the reason and build a new one, and install it the next maintanance cycle.

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    3. A Super Tomcat would have been significantly inferior to the Su-27.

      It would not have matched the SU-27's fuel fraction and the aerodynamics would not have allowed it to be anywhere near as good.

      Actually even the Su-27 is less than optimal in some regards. The engines to the rear are too widely spaced. While good for survivability, it comes at a huge cost, a weakness shared by the F-14.

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    4. I should clarify - a Super Tomcat vs an Su-27 at equal technological levels anyways.

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    5. You seem to have a near exclusive focus on fuel fraction as your measure of worth of an aircraft. There are other measures of worth that, depending on the intended function of the aircraft, might render fuel fraction (range) irrelevant. The Tomcat, for example, in its day and intended function had all the range it needed and coupled with the Phoenix missile and AWG-9 radar made the Tomcat a fantastic fleet interceptor.

      Longer range is always nice to have but once you have enough range to accomplish your mission, you don't really need more.

      As a ridiculous example, an aircraft could infinite range and endurance but if it only has a single Sidewinder, it's pretty much useless as a combat aircraft.

      I'd love to see you evaluate aircraft relative to their intended functions rather than against a completely arbitrary and often irrelevant single factor.

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    6. Because fuel fraction is extremely important.

      There's the range part, as defined by the Breguet Range Equation:
      http://web.mit.edu/16.unified/www/FALL/thermodynamics/notes/node98.html

      That directly affects ferry range and combat radius. But it's so much more.

      If you get into a dogfight, then it is often not the pilot with the most skill, but the pilot that can outlast the enemy that will win.

      In the Battle of Britain for example, the Luftwaffe pilots were extremely limited by low fuel supplies. Basically a few minutes and they had to turn around. It was a huge and decisive advantage.

      It's not just pilot skill, it is about endurance.

      The thing is, you don't have to sacrifice much. You can still build a very aerodynamic aircraft and have a good air to air payload.

      The other part of the range equation is of course L/D (lift to drag). In other words, more aerodynamic at the most used velocity is better.

      Plus fuel gives you options elsewhere. You can choose between range versus maximum cruise speed by altering engine thrust levels. Not to mention, cruise speed will be higher to begin with in an aerodynamic airframe anyways because it has less drag.

      Supercruise is only useful too with a high enough fuel fraction. The F-22 can only sustain around ~225 nautical miles with supercruise because it's fuel fraction is 0.29. That isn't that far and is only a few minutes.

      Likewise, if you do want to light up the afterburner, a higher fuel fraction can give a few more minutes on afterburner (afterburners can use as much as 10x fuel compared to dry thrust).

      Another advantage is the reduced dependence on fuel tankers and drop tanks. Tankers are vulnerable and mean that more money has to be spent on the tanker (plus any escorts), which means fewer attacking aircraft.

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    7. You're repeating my caution to you. You're focusing exclusively on fuel fraction. As I acknowledged, it's a useful thing to have but it's hardly the only, or even most important, design criterion.

      To use your own example of the Battle of Britain, the fuel fraction of the RAF aircraft was irrelevant. Far more important was speed, maneuverability, and firepower.

      C'mon, be accurate. There have been very few recorded dogfights that were decided by fuel. Dogfights end in moments or a very few minutes. The Cunningham dogfight was one of the longest on record and it was still over in a matter of minutes and not decided by fuel. If I thought hard enough I might be able to recall one or two out of the many hundreds I've read about. I'm sure there have been many instances where combat was declined due to lack of fuel but that can happen to the most fuel efficient aircraft, not just to short legged ones.

      A few minutes one way or the other on afterburner is irrelevant. I can't recall a single report of an aircraft ever being shot down because of a couple of minutes less afterburn time.

      You've latched on to one factor and made it the only factor in your evaluations. Armor, firepower, maneuverability, radar, stealth, etc. are all as important or more important that fuel fraction.

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  2. Here is a thought experiment. Should the Navy develop maintenance upgrades for the F-35?

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  3. One more thing from that article. And this just hurts.

    "A side note: I once talked to an accomplished engineer that worked for Grumman on the Super Tomcat 21 proposal. He told me that the performance models they were seeing with the Super Tomcat design were absolutely stunning and the jet's low speed handling, especially with thrust vectoring and the bigger engines, and the sheer amount of territory it could cover in a single mission were unprecedented. This man went on to work for "other contractors" on major fighter programs, but he maintains that the Super Tomcat's maneuvering performance and ability to operate as a fighter independent of tanker assets over large distances has still not been accomplished in any US or foreign design to this day. He did mention that he does see a large degree of the Super Tomcat's potential in the Russia's late model Flanker series, especially with its thrust vectoring and large internal fuel, but according to him it still does not really compare."

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    1. What you mention kind of makes you wonder just how much of an improvement over the then-existing F-14s would have been considered "enough" by those in charge. They ended up with the F-18, so perhaps their sights were set too high given how well then-existing F-14s did ground attack duties.

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    2. And that, if I recall correctly, they had to use bombcats to open up the war in Afghanistan because the SuperHornets didn't have the range.

      It could certainly fill the attack role.

      http://foxtrotalpha.jalopnik.com/this-topgun-instructor-watched-the-f-14-go-from-tomcat-1725012279

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  4. 1. I gather one (of many) theme, from all your posts I read so far, is head butting between warfighter (i.e. performance driven) vs. bean counter (i.e. $$ driven). Both are officer track, top-down, powerful parties. However, this article you introduce another concept (design for maintenance upgrade) which, to me, is actually bottom-up driven from my experience. What I mean is: who knows the maintenance tasks (and how-to-improve) best; they are the guys who had to take the stuff apart and put them back together. How much say do they have in your organization.

    2. The current CAD product starts to incorporate 'design for assembly' function. But, in all honesty, most users (including me) are not too bother with it; we still design parts as if they are weightless in space with all accessibility. Maybe military/production design is different; we are more of R&D prototype environment.

    To me, to get this going, the organization really needs to be engineering/product driven, its culture flat/bi-directional/flexible, and 'nuts & bolts' unglamorous tedious task driven, and with basic design good/stable/modular/longevity (which allows time for upgrades).

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    1. "I gather one (of many) theme, from all your posts I read so far, is head butting between warfighter (i.e. performance driven) vs. bean counter (i.e. $$ driven). Both are officer track, top-down, powerful parties."

      You need to read more posts (you need to read all the posts!). I have never acknowledged "head butting". That would imply that accounting is to some degree equal to warfighting and that is not even remotely correct. In fact, I've explicitly stated that the military is not a business, that business principles do not apply, that military needs are driven by combat requirements, and that many (most?) weapon and systems may be cost ineffective. Combat is the driving force for acquisition, not accounting.

      Accounting can't be totally ignored but it does not drive the military requirements and acquisition process.

      The military got in trouble when it tried to apply business principles. We wound up with minimal manning, deferred maintenance, reduced training, simulation over reality, etc. - in short, a hollow military.

      Let's be clear about this. Combat drives acquisition. When it doesn't, you get the problems we now have.

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  5. I am not in any way an aeronautical engineer, but I do wonder whether the problem is not this:

    (1) we want new aircraft (improved version of existing aircraft, or totally new aircraft) with greatly improved performance.

    (2) we want the new aircraft to be much more easily maintainable.

    So far so good, who could argue otherwise, but:

    (3) greatly improved performance will require more complex systems, and

    (4) more complex systems are more difficult to maintain, because there are far more things that might go wrong. and promises of miraculous diagnostic are not credible.

    I have run into this problem in non-military matters. Can someone explain why it does not apply here?

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    1. Outstanding observation and I think you're pretty much on target. This trend towards technological complexity is in direct contradiction of the KISS principle and should give us serious pause as we ponder the design of our next wonder-warmachine.

      Great comment.

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    2. The largest cost in aircraft maint is people, is how many are needed($) and how many maint man hours per flight hour are required.($)
      SW intensive diagnostics can help but take years to pay off. We know how much a line of code costs.
      Look at the cost flt hour for the V-22 as an example. Still atrocious it has come down some but not as much to even match all the claims made early on.
      Theres the rub.

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    3. "The largest cost in aircraft maint is people..."

      I disagree with that statement for the following reasons.

      1) Replacement parts, particular electrical components cost regularly above 300k dollar mark, in my experience at least.
      2) Unless its contractors performing maint, the income for service members isn't hourly. You could have a squad do 18 hours days or 3, and still be paid the same.

      In my opinion, electronics are the biggest cost driver in maintenance, for 1) and they are susceptible to more failures then actual parts.

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    4. "2) Unless its contractors performing maint, the income for service members isn't hourly. You could have a squad do 18 hours days or 3, and still be paid the same."

      And watch retention crash, spiking training costs orders of magnitude above the the saved hourly.

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    5. Retention is already down as well as enlistment (at least for the army). Have to be honest, your the first person I've seen make that logical conclusion. You must be prior service lol.

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    6. "This trend towards technological complexity is in direct contradiction of the KISS principle and should give us serious pause as we ponder the design of our next wonder-warmachine."

      Wasn't the F-14 denigrated for the non-KISSy nature of its swing-wings though? Even with those it was still very sturdily built (as expected of the old "Grumman Ironworks") and could limp home with a missing wing or safely land with wings that were asymmetrically swept, but I don't think those features counted for much in the minds of those who touted the F-18 as a simpler, cheaper, do-it-all platform (the last of which didn't prove true).

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  6. Your concept of "maintenance upgrades" exists and are called OSIPs operational safety improvements programs. This appropriated monies used for those purposes you discuss. While not as effective as one would like their budgets are extremely volatile year to year which doesn't help. Normally ACAT 3, they make up a good chunk of the NAVAIR workload. Often with emergencies like the present hornet depot dilemma or the P-3 wing issues last decade, their budgets are shifted for more immediate needs often stretching out installs for years. I have my opinions but that is the basic information.

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    1. That's a nice piecemeal approach but I'm talking about comprehensive maintenance upgrades where, for example, we might rip out the entire hydraulic system of an aircraft and replace it with a newer, lower maintenance version.

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    2. Piecemeal? Every aircraft program of record has an osip budget and they add up to billions for those "improvements". Literally hundreds of them for every platform in the inventory. Sustained funding of them is problematic.
      Yes, sometimes we R&R hydraulic systems. Every platform has a priority list ranked in order that the NAE sets and capitalizes. Over 1/2 the $$ effort at navai goes to OSIP NRE and installs. The depots are full. Hornet SLEPs are a typical example.

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    3. I fear that you're still not understanding my concept. As an aircraft goes through its life, there are upgrades of various sorts applied to it. All well and good. What you're talking about seems to fall into that category. Perhaps it's the major source of upgrades. I don't know.

      However, what I'm proposing is a systematic gutting of an aircraft to remove whatever systems are deemed to be high maintenance, even if they function perfectly, and replace them with lower maintenance versions.

      An example would be the Tomcat. By the end of its life it was deemed high maintenance. My proposal would have been to gut any system in the aircraft that was deemed high maintenance and replace it with an equivalent lower maintenance system. Obviously the lower maintenance versions existed because they went into the Hornet. So, we could have kept the superior performance of the Tomcat and incorporated the reduced maintenance of the Hornet.

      If this is what you're also describing than it's clearly not being done on a scale that makes any difference in this context - in other words, it's piecemeal, if it's even the same thing which I'm sure it isn't. No one I've ever talked with has ever brought up wholesale maintenance upgrades. Yes, a less maintenance intensive valve might get swapped out but wholesale gutting of a subsystem, no.

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    4. Yes. They are a major source of upgrades. To simplify I'll relate facts as an example. The P-3C was put into service in 1960s and is till being flown today. Installations only occur through technical directives based on ECPs. AFCs are the installation instructions to install the type changes you are describing.The P-3C series aircraft is on AFC-850. The F-18C legacy hornet is up to the mid 400s for AFCs maybe higher. Tens of billions worth. That is how aircraft are upgraded without downing entire fleets required on the line. This is NAVAIRs work.

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    5. To go further these are not always done by the OEM and most do not change the latter of the model A to B for example. The majority are to improve R&M as class 1, 2 or 3 ECPs.All this information is documented publicly and most of it uses appropriated funds not OMN funds.

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    6. It's clearly not being done on the scale I'm describing because every time we want a new ship or aircraft we denigrate the existing one by bemoaning its excessive maintenance requirements. That wouldn't happen if the kinds of upgrades I'm describing were occurring. Clearly, they're not.

      The classic example is the F-14. Its replacement was justified almost wholly on maintenance costs. I'm not naive enough to believe that was the only factor but if it had received the kind of upgrades I'm describing, rather than piecemeal upgrades, maintainability wouldn't have been a factor at all!

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    7. Can't speak for ships although the longest pole in the tent is structural life. The Tomcat was put away in 2004 out of fatigue life. Even with expensive SLEPs the Hornet series gets another 2-3 k flight hours. At 250 hrs a year at best they don't last long. Plus the out of reporting takes a long time plus it taxes our industrial infrastructure. A new machine has all kind of R&M gimmicks built into the sales pitch but I have never seen. It borne out
      Even the P-8, a commercial derivative, is way behind what had been expected R&M wise.
      Naval aviation is a harsh environment. Alarm bells should go off in peoples heads who budget do this, although I have never seen it. Shiny new object you know....

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    8. Fatigue life, or end of service life in general, is an arbitrary concept. We can rewing, re-engine, refuselage, re-anything, if we want. Consider the B-52 example. We use "end of life" as an excuse because we want new toys and continued budget slices.

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    9. Could the F-14 really have been upgraded with "lower-maintenance" stuff though? One of its core features was its swing-wings, more complex than the fixed wings used by every US jetfighter since. This apparently was the main reason why it was considered "high maintenance," that and how it didn't have automatic diagnostic computers like the F-18 did to aid in maintenance (or so I heard), forcing everything to be checked manually each time (which meant more paid hours for the maintenance staff).

      Sure, the F-14 was never upgraded with certain newer technology like Fly-by-Wire, Thrust Vectoring, or Radar-Absorbing-Materials, since it was "1960s technology" to quote Dick Cheney, the main proponent for the cancellation of the F-14. But those same swing-wings were one of the main reasons why the F-14 could take off with a much higher payload than the F-18, be fuel-efficient across a wide variety of speeds, and still make fast dashes for low-level penetration bombing or interception, not to mention carry a lot of air-to-ground weaponry a long distance and still be able to fight air-to-air very well at the same time.

      The problem is, how were the "upgrade the F-14" proponents supposed to make their case in a fiscal environment focussed on cost-cutting? To their opponents, the F-14 was outdated, a money sink in terms of maintenance costs, and didn't see much life-or-death combat. But in some ways you got your money's worth with the F-14.

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    10. When you get right down to it, how is a swing wing any different than a folding wing which every carrier aircraft has? A swing wing is as complex or as simple as you choose to build it.

      I don't know if the swing wing was actually a source of high maintenance or not - I would tend to think not but I don't know. Even if it were, it's not the wing itself that's complex, it would be the valves, piping, motors, and whatnot that operate the wing. Those can be replaced and simplified, if desired.

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    11. I'm just trying to pass on information about how things are done because you seem interested...

      Fatigue life and the other things you mention are not "arbitrary" concepts. Like a paper clip bent to-fro until breaking all aluminum structures underlying any aircraft wears out until it becomes unsafe to operate even with restrictions. Based on flight hour cycles- landing, cat shots, excursions, etc. they are a finite and measurable resource.

      They all take NRE/design and schedule and kit manufacture and installation time and more schedule while concurrently the aircraft are Out of Service. Time/money. Nothing is simple- the devil is in the details.

      Sometimes the US Navy does not own the design or just owns part of the underlying design setting up data rights problems. On the industrial side there is only so much capacity in this country. many other considerations...

      Making these upgrades happen does not happen by .ppt....

      I have considered the B-52 and the P-3 and many other aircraft. We got more than our monies worth out of the F-14 and A-6 TMS.

      Why? some may ask, did the S-3 Viking, a unique purpose-built aircraft, perfect for US Naval Aviation needs get retired with only 1/2 its service life remaining?

      Because leadership sundowned it in 2001 and reprogrammed the Vikings budget before the results of the Full Scale Fatigue Test came out in 2003 showing the added life. Nope, they made their decision to "can" the Viking because they expected the results to reflect similar results as the F-14! Did they overturn their execution upon learning this? Of course not, they would look stupid. Go to www.navy.mil, under "fact file", S-3B and read the last paragraph. Its in there.

      Some people would just say win some, lose some....I don't. We have to win every time if we can.

      B2

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    12. I think we did get our monies worth out of the F-14's, but I also think the line was shut down way to early.
      By the late late 90s it seems there was little effort in doing anything with the Tomcat except flying out its life. I bet that will be the fate for the SuperHornet.

      The Tomcat was a great naval platform with alot of growth in it. Had they come out with a SuperTomcat 21, or an F-14E with everything the D series had, plus deliberate improvements in maintainability, maybe they could have remanufactured the D's to a higher level like they did the A's.

      You do bring up alot of good points. It would be really interesting to me to see what a C series hornet in the fleet today would look like compared to its factory original self.

      No matter what happens, I think NAVAIR is in big trouble, trying to wait for software choked F-35's while flying the wings off of Superhornets and trying to desperately SLEP ancient C's.

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  7. We look fondly on the Hornet when we compare it to the F-35 but we forget that the Hornet is ill-suited to the Navy’s actual operational needs – and I’m being polite about the ill-suited part. The Hornet is a huge failure by any standard other than comparison to the F-35 which speaks more to the magnitude of the F-35’s failings than any strengths of the Hornet."

    Does this mean you're going to do a blog entry going into just went wrong with the Navy's decision to go with the F/A-18 rather than upgrading the F-14 (which in some ways was better at F/A roles than the F/A-18 was in practice)? I think you'd make a very interesting analysis.

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    1. There have been books written on this subject and they can do justice to the topic far better than I can in a short blog post!

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    2. I've liked your blog entries so far giving analyses of problems, and I also feel you'd have a unique and interesting take on this. A "short blog post" from you would still be a fresh perspective on this.

      Which books did you have in mind, though?

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  8. Short comment because I'm drunk :)

    The problem for "minor upgrades" is that military aircraft are subject to civilian flight restrictions, which are draconian and cautious.

    You cant just replace a part, because once you do, you have created a new aircraft, which requires a new flight safety certification, which is expensive to get.
    We do upgrade aircraft, there are 8 Typhoon variants, and its barely in operational service.

    All that said, "maintenance" costs are, in my understanding, primarily depreciation costs.
    Not always of course

    The F14 was likely so high because of its variable wings, which were so costly to maintain that the RAF locked them in place on the Tornado, it was cheaper to use afterburners all the time.

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    1. Doesnt seem right, the military have their own flight standards and certification standards. Different military have totally different processes, ie RAF maintenance squadron is run by a professional engineer which US Marines ( may be same for other Us branches) have a pilot running their engineering squadrons.
      The USAF is doing something unique with its KC46 tanker in that the mods are going to be FAA certified, I imagine to tap into existing 767 parts system.

      Typhoon has been in service since 2003 so thats nearing 15 years. The issues are about the different requirements of the multi nation users. Locked swing wings on Tornados doesnt seem to be referenced elswhere and seems illogical, what may have happened was the 'auto sweep' function on the F3 was found to be loading upfatigue index if sweep changed during sharp turns so was turned off. Manual sweep was still required !

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    2. Here's a new example of a maintenance upgrade that's in the ballpark of what I'm talking about. This one is for the entire Marine CH-53E fleet. From dodbuzz.com,

      "... each Super Stallion will spend approximately 110 days in a reset process that will involve stripping the aircraft down and rebuilding it while replacing any aging components."

      If we can do this, we can certainly do the type of complete maintenance upgrade I'm suggesting.

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  9. Swing wings might have been more complex, but there are ways to improve it.

    25 years ago anti lock braking systems were very complex. Now they are commonplace.

    The computer that controlled the sweep was groundbreaking at the time. Today an ipod touch could do the same thing.

    One thing that might help would be to make things more modularized in the initial design; so that its easier to pull out hydraulics. I believe that's one of the things they did with the Superhornet's avionics.

    Again, I think a big issue was that Navy leadership in the 90's was just short sighted, and afraid to tick off Dick Cheney. So they went with a new build SuperHornet rather than a new build SuperTomcat. So they went with the short legged plane that looked less expensive rather than the higher performer.

    This short sightedness continued, IMHO, with the F-35. Again, we have a follow on plane without enough range to help the CVN.

    It is what it is. Maybe the Navy can help itself by buying the CFT's with new SH purchases, and retrofitting old ones. And maybe they can add stealthy CFT's to the F-35 (though I don't want to think what that would do to the performance of the already thrust challenged C model).

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    1. The problem is that as swing wings improve, regular wings too.

      There will always be a mass and complexity penalty for swing wings. The problem is, is the trade-off worth it?

      You get:
      + Lower fuel consumption on the take-off landing
      + Lower take-off/landing speeds

      Drawbacks
      - Reduced flight to maintenance ratio
      - Reduced fuel fraction (mass of swing wings)
      - Reduced cruise speed and dogfight performance
      - Higher cost to buy aircraft

      I'd say the drawbacks vastly outweigh any advantages. IMO, a tailed delta or a tailless-canard delta is a much better design.

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    2. Fair enough, but that wasn't the point I was trying to make.

      I know you don't like the Tomcat, but even if all the negatives are taken into account, I still think its pretty clear that had we stuck with a SuperTomcat 21 we'd be in better shape than going down the path of the SuperHornet.

      Would the swing wings have made a maintenance penalty vs. a fixed wing? Sure. But you can make them better so overall maintenance of the aircraft is within reason.

      A clean sheet design could have been even better. I like the navalized flankers, but nothing like that was on the boards at the time, so the point is moot to me.

      Given the choice between SuperHornet in our airwings today and SuperTomcat 21 I'm going the latter every day of the week.

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    3. "Drawbacks
      - Reduced flight to maintenance ratio
      - Reduced fuel fraction (mass of swing wings)
      - Reduced cruise speed and dogfight performance
      - Higher cost to buy aircraft"

      What is with this swing wing bashing?

      How is a swing wing inherently more complex and maintenance intensive than a folding wing which is not considered to be complex or maintenance intensive?

      How is the mass of a swing wing significantly greater than that of a regular wing of comparable size? They both require structural reinforcement (spars or some such). The structures simply have different shapes.

      How does a swing wing reduce cruise speed? The whole point of a swing wing is to allow selection of the optimum angle for any given speed.

      How does a swing wing hurt dogfighting performance versus a comparable size aircraft?

      Why is a swing wing aircraft more expensive? Sure, a few extra dollars for some additional hinges and motors but it's hard to see how that's a significant cost increase or a significant portion of the overall cost.

      If you want to bash the swing wing then offer some data or logic to support it.

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    4. The answer is because the swing wing is a very complex piece of technology that is very delicate. In some ways, it is like a rail gun or the delicate radars on the Aegis.

      To make the aircraft wings swing, there are a pair of two ton motors in a box that have multiple moving parts. That is mechanically complex (hence maintenance intensive). Needless to say, this complex piece of technology is very expensive. Those "hinges and motors" don't cost a "few extra dollars", they cost a lot of money. The F-111 and F-14 were very expensive aircraft. The B-1 too blew away its budgetted costs.

      On the F-14, the box itself that did the swinging was about 2 tons and then there is the motor and hydraulics. Within that box are lots of moving parts. That is a huge point of failure. That would mean that for a given fleet size (already reduced by the expensive procurement costs), you would have an inferior flight to maintenance ratio, leading to a much lower sortie rate. The sweep mechanism also uses a lot of space inside the aircraft as well, which could otherwise be used to store fuel or payload.

      In combat, when the aircraft did fly (you would not be able to buy as many for a given budget compared to a fixed wing because of the procurement costs and those that were bought would not fly as often), you would have an aircraft heavier than a competing fixed wing aircraft because it weighs more thanks to the "swing" mechanism. That would lead to the lower thrust to weight ratio, which leads to a lower cruise speed (because of the extra mass of the swing mechanism). Weight is an extremely important part of any aircraft design. Anything that adds weight is not desirable, more so when it worsens reliability. Although fortunately, the Cold War never turned hot, I suspect that in combat, the swing mechanism would prove fragile.

      The other problem of course is that adding weight reduces payload and range (even though the swing wing can somewhat compensate for this, it cannot make up for the considerable weight penalty). You'll notice that the "swing wings" don't carry heavy missiles on the wings themselves, unlike conventional aircraft wings. They don't carry as much fuel either in the wing, unlike say a tailess delta which can carry a lot.

      Basically the mass and reliability problems of the box and hinge negate any of the advantages of the swing wing, plus then some. Not to mention modern technology gives many of the benefits. I should also mention that although I don't have a high opinion of radar stealth, it is not possible to make a very "stealthy" swing wing aircraft due to the shape of the aircraft.


      I don't have time to look for sources, but here are a few answers:
      https://www.quora.com/Why-did-aircrafts-stop-using-variable-sweep-wings-like-those-on-an-F-14

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    5. I don't have data for this but I strongly suspect you're taking data out of context or using it in isolation. For example, the Tomcat swing mechanism (do you have a reference for 2 tons? I doubt the number) is almost certainly not a case of two additional tons. If it were a conventional wing it would have spars or some such attaching and supporting structure which would weigh something. The question is not what did the swing mechanism weigh but what was the differential in weight between it and a conventional structure? I suspect (but have no data) that there is relatively little net difference in weight.

      I strongly suspect that the wing motors do not weigh two tons, as you claim. A two ton motor could lift an aircraft carrier! It might be a two ton capacity motor but that's not the same as the weight of the motor! Give me a reference for that weight.

      As far as weapons on the wings, the Tomcat did not need them. The Tomcat had plenty of weapon space under the fuselage and on the wing support area. In fact, having the weapons tucked into the fuselage undoubtedly reduced drag compared to conventional wing weapons carry thereby increasing range and speed. It also would improve stealth although the Tomcat was not a stealth aircraft.

      The swing wing was no more complex than folding wings and was not "delicate". Out of all the gazillion flight hours, there might have been one incident of wing failure.

      The swing wing also eliminated the need for folding wings which would have saved folding wing mechanism weight and reduced folding wing mechanism maintenance. A significant savings over a conventional Navy aircraft wing!

      As time went on, the swing wing was no longer needed but it was hardly the horrific monstrosity that so many people now believe. For its time, the swing wing was a successful piece of advanced technology and more than met its requirements. It offered the Tomcat many advantages in its intended role as a fleet interceptor and carrier aircraft.

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    6. I'd have to disagree with you on the weight part, although I will have to check later.

      I'm sure though that it is quite heavy and complex. Actually in the case of one planned aircraft, the Boeing SST (which was to be an American Concorde, more less), the mass of the box beam and wing pivots was so big that the design had to be abandoned for a delta-winged design.

      On the weight on the wings, if an equivalent mass aircraft can carry more weapons, then it is superior. The Su-33 for example, can carry weapons on the folding wings:

      http://www.ausairpower.net/V-MF/KnAAPO-Su-33-4.jpg

      Yes, there is a penalty for folding wings (cannot sustain high g's), but it's not nearly as bad as for swing wings. Folding wings are a much simpler technology and have been around since WW2.

      https://i.stack.imgur.com/bm29T.jpg


      A SuperTomcat 21 would have been a lot more expensive than a Super Hornet and would have been inferior in many regards to a Western equal to an Su-33.

      I should also mention one other drawback of variable swept wings - the wing loading is high due to small wing area compared to a tailless delta. That would be a drawback for dodging missiles that are incoming and would be really bad in a dogfight.

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    7. "I'm sure though that it is quite heavy and complex."

      Was heavier than a conventional wing support structure? Give me a real number and then we'll know. Say, an F-15E/C? Until then, the increased weight is something you're speculating on rather than a fact. Odds are it is heavier but my guess is not by much.

      As far as complexity, I've seen the public drawings and it doesn't look very complex to me at all. It's actually rather simple. I've never heard of a documented wing swing failure or even any particularly onerous maintenance requirement. Again, if you want to make the claim, prove it. Provide some data or examples of myriad failures.

      "On the weight on the wings, if an equivalent mass aircraft can carry more weapons, then it is superior."

      No. It is superior if it can carry more weapons. It doesn't matter where they are. The Tomcat had 10 hardpoints and could carry 12 weapons on those 10 hardpoints (the glove hardpoint used multiple racks that carried 2 weapons each). Potentially 12 weapons is outstanding. The Su-27, I think (check me on this) has an identical 10 hardpoints.

      Also, wing hardpoints are significant sources of drag. By comparison, the Tomcat's 6 fuselage hardpoints impose minimal drag penalties and are far superior to the Su-27 or any wing-loaded aircraft. You're really not being objective in your analyses.

      "A SuperTomcat 21 would have been a lot more expensive than a Super Hornet"

      Come on, now. You can't have any idea what the cost would have been. Besides, it's not the cost, it's what you get for the cost and, again, we don't know what a SuperTomcat, today, would have given us.

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    8. Alt, you seem to have both an interest in aircraft and some degree of knowledge. I'd love to be able to use you as an expert source of information and evaluation. You could be a wonderful resource for this blog. Unfortunately, you seem to have only one criterion for aircraft design, fuel fraction, and you seem to have a tendency to pick points out to win arguments rather than perform objective analyses and comparisons. A phillips head screw may save a tiny fraction of a milligram of weight over a slot head screw so, in theory, an aircraft built with phillips head screws is superior. However, in practical terms, it has absolutely no impact. Yet, these are the types of arguments you're making in an attempt to "win" a point rather than analyze.

      You're also ignoring roles. An F-14, for example, was not intended to be a pure dogfighter. To criticize it for its dogfighting shortcomings in comparison to an F-22, for example, is to completely miss what it was designed to do.

      I would love for you to be an expert resource for all of us but in order to do that you need to be objective, practical, and ensure that when you make statements that they are based on data. There's nothing wrong with speculating as long as you make it clear that that's what you're doing. For example, I might say that logic suggests, but I have no supporting data to prove it, that the swing wing support structure is heavier than a conventional wing's support structure and my estimate is 20% heavier.

      You also need to quantify the practical impact of your points. For example, a phillips head screw aircraft is superior to a slot head screw aircraft but the practical impact of the difference is negligible.

      If you're willing to do this you can be a valuable resource for me and the readers of this blog. If not, I'm forced to discount your assessments which would be a loss of the knowledge you seem to have. What you're doing now is hurting the credibility of your comments.

      Take the "win the argument" approach out of your analyses and, instead, provide objective assessments and I'll look forward to all your comments!

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    9. Alt, do you have any interest in doing a guest post on what a SuperTomcat could have been, today, if we had not gone the Hornet route? It would be interesting to compare what a modern SuperTomcat would look like compared to today's F-18E/F and even F-35.

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    10. @CNO

      I'm too busy right now to do that in much detail, but briefly, my thoughts:

      You are right that a F-14 is not intended to be a pure dogfighter, but it will inevitably in its job get intercepted by enemy fighter aircraft. The problem is that you need either an aircraft that can either outfight or outrun an enemy.

      Although I have praised the Su-27 variants, it is not a very good dogfighter (better than the F-14, but still not awesome) and although it is at a drawback in transient performance, it does have the option to try to outrun the enemy.

      As far as a modern F-14 Super Tomcat - what it might look like?

      It would be faster than the old Tomcat at cruise speed, although maximum afterburner speeds may be unchanged. It's not a huge drawback and cruise speeds are far more important.

      A modernized missile variant of the AIM-54 Phoenix would have been procured, perhaps extending its range. It would be dangerous against larger aircraft (fuel tankers, enemy AWACs, and perhaps most importantly as a interceptor, enemy bombers). It would not be very effective though against smaller aircraft that are more agile (ex: like fighters). The AIM-54 did not do so well in USN hands historically against enemy aircraft. There are claims though that in the Iran-Iraq war, Iranian F-14s did get several kills against Iraqi aircraft, but keep in mind Iraqi pilots were not well trained.

      But the reason why I focus on a few characteristics is because we are comparing what a hypothetical "modern" F-14 might do versus an equal technology alternative.

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    11. I'm disappointed but perhaps another time?

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  10. "A SuperTomcat 21 would have been a lot more expensive than a Super Hornet and would have been inferior in many regards to a Western equal to an Su-33."

    That isn't what I've read. I guess we'll have to agree to disagree.

    Yes, the ST21 would have been more expensive than an SH. But we're there now with the F-35. And the purchases would have been made in a more permissive budget environment (without sequestration).

    In return we'd have an aircraft with likely double the range of the SH without gasbags; real top end, and the ability to hoist alot of ordinance.

    Those 3 things right off make the carriers more effective than they are now; and give us more options for an A2/AD environment.

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    Replies
    1. Fair enough, a F-14 "Super" would no doubt be a better interceptor than the F-35, and would be able to double up as a "Bombcat" still. The challenge with the F-35 is that it is at its weight margins already, and the payload is very limited. That's not even considering the current crop of reliability problems the F-35 faces.

      Still, I think there are better alternatives. The Dassault Rafale is a good example of an alternative, although it's more of a fighter than anything else (it a good dogfighter and can also carry bombs).

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    2. I don't think we'd ever get the government or Navy to go for it, but I'm 100% on board with that. If we could license build the Rafale I think it would make a very nice core aircraft for our CVN's.

      From Wiki:
      Combat radius: 1,852+ km (1,000+ nmi) on penetration mission
      Maximum speed:
      High altitude: Mach 1.8 (1,912 km/h, 1,032 knots)
      Low altitude: Mach 1.1 (1,390 km/h, 750 knots)

      With a 1000 nm Combat radius, and coupled with AIM-120D or meteor, the carrier can both perform strike missions from *much* farther out and also perform a good fleet defense role (good range/loiter time + long range of AIM-120D or Meteor)


      Then there's this:

      "It is the only non-US fighter type cleared to operate from the decks of US carriers, using catapults and their arresting gear, as demonstrated in 2008 when six Rafales from Flottille 12F integrated into the USS Theodore Roosevelt Carrier Air Wing interoperability exercise.[234]"

      Finally, doing this might give a kidney shot to US defense contractors.

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    3. I flat out don't believe the combat radius claim. As you know, you can make almost any claim by manipulating the loadouts and flight profiles. This claim seems ridiculously high. Consider this comment from Wiki on Rafales in the Libyan conflict,

      "During the conflict, Rafales typically conducted six-hour sorties over Libyan airspace, ... these patrols required multiple aerial refueling operations per sortie from coalition tanker aircraft."

      That does not lend credence to claims of 1000+ mile combat radius.

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    4. Good point.

      How about this, I'm not enamored with Rafale so much as I am with a nearly 1000 mile combat radius.

      Give me a plane with a good combat radius, and a good bring back and cruise speed, and I'll be a happy man.

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    5. I read this over the weekend:

      http://jerryofgarcia.kinja.com/f-35a-fuel-fraction-findings-1783148610

      Now I'm all confused. He seems to have a different take on fuel fraction (one I hadn't considered); that being that you can go do high, because the more fuel you bring aloft, the bigger the engine you have to have, and that you can reach an efficiency tipping point.

      That said, I'm all for big fuel fractions, and he seems to think the F-35A is fine in its fuel fraction and might do better long range because it can be mission capable and still fly clean, unlike other aircraft which look better on paper but aren't as efficient because they have to haul around their ordinance externally (I.E. a Strike Eagle or Flanker looks way better on paper, but load it up with tons of missiles and bombs and the drag makes it worse or much closer).

      Given the other issues we know the F_35 has, I'm a bit skeptical. But its not something I'd read before.

      I did try to do some fuel fraction calculations myself to come up with real comparisons, but was having a hard time finding good numbers, and defining some numbers (I.E. what does loaded weight mean) so I left them out.

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