Defense Issues

Military and general security

How to reduce fighter aircraft costs

Posted by Picard578 on May 15, 2015

There are three basic principles of fighter aircraft cost reduction:

  1. keep it small
  2. keep it simple
  3. keep it single

However, they are not the only relevant issues; others will be adressed here as well.

Keep it small

Empty weight is a major factor in aircraft’s cost, since higher empty weight (larger aircraft) means more materials used as well as more man hours of work to build it. Thus smaller aircraft are also cheaper, assuming identical technology level. Further, smaller aircraft use less fuel and have lower operating costs.

Keeping aircraft smaller will also improve its air combat ability, as it will improve ability to achieve surprise as well as transient performance, which is crucial for outmaneuvering the opponent.

Keep it simple

This should be true for both development and the final product. Design group should have one person overseeing the process, and one engineer for every area (reliability engineer instead of group dedicated to reliability, for example). It should be small enough so that all people in the group can effectively work together at a single place. Management should be hands-off, so that once design goals have been provided in broad outlines, neither the military or upper levels of the company interfere with the design process. Military in particular should only define what weapon should do in broad outlines, and leave it to company to decide on how weapon will achieve these goals.

Formalization during process should be minimized – military should get the same data, and in the same format, as the design group, and it shouldn’t go through approval cycles.

Keep it single

This is a key factor in keeping the aircraft simple while achieving adequate effectiveness. Fighter aircraft should be single-role, single-engined and single-seat (except for training variants). It should also be designed for a single service, and then adapted for other service(s) if at all possible.

Typically, multirole aircraft cost as much as all the types they are replacing placed together (unless there is an overlap in capabilities between said types). This is because multirole aircraft have to carry far more extensive sensor and avionics suite and have to fit more requirements than single-role ones. An air superiority fighter is ideally small, single-engined, with either no or a small radar, as well as good cockpit visibility and passive sensors suite. Ground attack aircraft can vary in size from small to extremely large, depending on role and requirements. They tend to have two engines, large total fuel capacity, a ground-following radar, and limited cockpit visibility. As a result of combining the requirements for two, a multirole aircraft tends to be of either medium or large sized, twin engined, with extensive sensors suite including radar and good cockpit visibility. Only exceptions from this rule aire aircraft that were designed for air superiority and then adapted for ground attack (F-16) or were primarily air superiority aircraft used by countries where range was not as much of an issue (Gripen). In both cases however there are still clear sacrificies made for the ground attack performance (increased weight and cost in the F-16s case, sacrificed rearward visibility in Gripen’s case).

Single engine helps reduce cost in several ways. Single-engined fighters are more amiable to area ruling, which means that they tend to have less drag and thus lower fuel consumption. This can also lead to reduced size, weight and thus procurement cost as well. Further, a single engine tends to have greater thrust-to-drag ratio than two engines producing equal amount of thrust, which leads to further improvement in fuel efficiency. Maintenance downtime required is also lower. All of this leads to single-engined fighters having significantly lower direct operating cost than twin-engined fighters (7.000 USD for F-16C vs 16.500 USD for Rafale C. Note that Rafale C has 11% greater empty weight, 28% more dry thrust, yet costs 2,36 times as much to operate as the F-16C. F-15C costs 30.000 USD to operate (or 4,3 times as much), yet has 48% greater empty weight and 52% more dry thrust compared to the F-16C).

When designing an aircraft meant for multiple services, best way is for it to make sure that it fits naval requirements. All successful multi-service aircraft – F-4, F-18, Rafale – were designed as naval aircraft and then adopted into air forces (YF-17 was designed for USAF, but the F-18 was designed for naval use from the beginning). Reason for this is that carrier aircraft have to fit far more strigent criteria in terms of size, airframe strength, corrosion resistance, landing gear design and cockpit visibility.

In terms of airframe strength, naval aircraft use safety factor of 1,85 compared to 1,5 for ground-based aircraft, meaning that they need stronger airframe for same operational g limits. For example, F-18 has an ultimate load limit of 13,6 g. USN F-18s are limited to 7,33 g compared to 9 g for Finnish F-18s. Rafale has an ultimate load limit of 16,65 g. While both AdlA and Aeronavale Rafales are limited to 9 g during normal operations, only AdlA Rafales have an override function that allows them to pull up to 11,1 g in flight (and this is regularly done without shortening airframe life).

Corrosion resistance is an issue for naval aircraft because they spend entire service life in very humid conditions. While some land-based aircraft may also face rather humid conditions in tropical countries, naval aircraft also have to withstand salt.

Landing gear is also more problematic issue for naval aircraft. It has to be strong enough to withstand stresses of rough carrier landings. This also means that it should be located in the body to relieve wings from stress. However, distance between main wheels should be large enough to provide a safe overturn angle (25* or more). Placement also has to allow for sufficient tail clearance during landing in spite of typically higher landing AoA than is the case with land-based aircraft, as well as room to install a sufficiently strong tail hook.

Out-of-cockpit visibility must also be good. In addition to standard requirement for providing 360* horizontal visibility, naval fighter also has to have excellent over-the-nose and over-the-side visibility to facilitate a safe approach and landing.

All of this will lead to higher production cost for an air force variant than would otherwise be the case, but will also mean significantly lower R&D costs. Production cost increase may also be compensated by having a significantly greater production run.

Start from the weapon

This is one of reasons for why aircraft should be single-role. When designing an aircraft, one should always consider what weapons will it use and how will it use them. This means that designs for air superiority aircraft – using gun and air-to-air missiles – will be very different from those for ground attack aircraft, which typically carry bombs and missiles far fatter and less aerodynamic than air-to-air missiles are. If done properly, however, it will reduce cost of both design, weapons integration and testing, and will lead to improved performance in aircraft’s role.

Use off the shelf components

Using off the shelf components where acceptable would reduce development time and costs, since not only some systems will not have to be developed, but some factors influencing the end design may also be known. For example, using an existing engine – even if planning for a future uprated variant of the same, or a completely new design of similar dimensions – will automatically point to some design and performance parameters. Using an existing gun means that some issues – concerning size and weight of a weapon as well as possible vibration issues – can be known before the design process even starts.

Optimize the production

Optimization of the production line also plays part in the cost of a fighter aircraft. Typically, cost falls the longer the aircraft is in production. This decrease is comparably small for modern fighters but in large numbers can lead to significant total savings. Entire aircraft should be produced in one place, so that any errors in production can be fixed as soon as possible.


26 Responses to “How to reduce fighter aircraft costs”

  1. Chris said

    The issue right now is that technology, people management, and everything else is not the bottleneck. The big bottleneck right now is that the defense industry likes the status quo because they can get fat off of it.

    That being said, this project management set of guidelines seems to be very similar to that of computer programming – Scrum for example. Massive teams are counterproductive.

    • picard578 said

      “The big bottleneck right now is that the defense industry likes the status quo because they can get fat off of it.”

      Agreed. And it actually reinforces itself – big design teams are forced on by technological complexity, but they only serve to make both management and design even more complex, which leads to delays and additional costs. Which is what industry wants.

  2. Chris said

    Reading this reminded me of the justification behind the rationale for the FW-190 design:

    The Messerschmitt 109 [sic] and the British Spitfire, the two fastest fighters in world at the time we began work on the Fw 190, could both be summed up as a very large engine on the front of the smallest possible airframe; in each case armament had been added almost as an afterthought. These designs, both of which admittedly proved successful, could be likened to racehorses: given the right amount of pampering and easy course, they could outrun anything. But the moment the going became tough they were liable to falter. During World War I, I served in the cavalry and in the infantry. I had seen the harsh conditions under which military equipment had to work in wartime. I felt sure that a quite different breed of fighter would also have a place in any future conflict: one that could operate from ill-prepared front-line airfields; one that could be flown and maintained by men who had received only short training; and one that could absorb a reasonable amount of battle damage and still get back. This was the background thinking behind the Focke-Wulf 190; it was not to be a racehorse but a Dienstpferd, a cavalry horse.

    Ernst Udet was critical in particular of the Bf109.

    Views on visibility:

    “From my own flying experience, I knew how important it was for a fighter pilot to have the best possible all-around view, and we decided to fit a large frameless bubble canopy to the new fighter. Later, these became very fashionable, but in 1938 the idea was something of an innovation.

    He did predict the increase in the rise in mass over time of planes as well, so he built that into the design:

    For the design weight and estimated landing speed of the prototype aircraft, we calculated that the undercarriage should withstand a sinking speed of 2.5 meters/second [8.5 ft./sec.] to be sufficient. But if the aircraft was developed [over time], its maximum speed, weight and landing speed would all increase. That would result in considerably higher forces on the undercarriage during landing. So in the original stress calculations, we allowed for a sinking speed not of 2.5 m/sec. but of 4.5 m/sec. [15 ft./sec.]. And then we designed the undercarriage to be strong enough to take that. The move paid off. During its life, the maximum loaded weight of the Fw 190 rose from 2.75 tons to more than twice that figure, but with few changes, the undercarriage remained adequate. I have used the undercarriage as an example, but in fact several parts of the original structure were a great deal stronger than the minimum necessary.

    They used very wide landing gear for that reason.

    • picard578 said

      Add to that the fact that FW-190, while not the best turner, had better transient performance than Me-109, and it could be said to have been the best Luftwaffe fighter of the war.

    • Chris said

      The Fw-190 I remember did have high wing loading, so turn rate was not as good.

      Out of curiosity, what fighter did have the best transient performance in WWII? I’d presume that would be the top fighter.

    • Chris said

      The big takeaway from this is that the Fw-190 was developed by someone who had seen war, who knew what lessons had to be learned, and who tried to apply those lessons.

      It seems to be the polar opposite of what the current status quo has become, which is a subsidiary for the defense industry.

      Another consideration is mass production – Chet Richards once noted that the best practices of civilian manufacturing were not going to go into fighters – for a number of different reasons. I think one that he did not elaborate on enough was that the status quo is “working” quite well for the defense industry.

  3. vyse said

    Picard, I have an issue against your idea that weapons like fighter aircraft should be single-role. Sure they can be better in their respective domain and at a lesser price. But…

    Life is never doing what we expected or wanted. And war is even worsening that statement.
    From my experience in real life if you leave with a hammer, you’ll soon need a corkscrew. But had you left with a corkscrew, you’d need the hammer. Then if you had got yourself equiped with both a corkscrew and hammer, you’d definitly need a wrench. Didn’t you experience that?

    IMO I you’ve got attack planes on a forward base waiting for orders to blow up ennemy tanks, you can bet you’ll need them to intercept ennemy aircrafts, escort civilian planes, or do SAR, etc… Having several specialised aircrafts on said base would obviously limit capability for each possible mission too. Pilots would also either be specialised to one type of mission, or need to be qualified to fly several different types of fighters.

    In the end I believe a multi-purpose tool will always suck at doing what a purposely designed tool do, but at least it can help in every scenario. However this supose it is really credible in a large job-spectrum, and not just fat attack bird stamped with wishful “multirole” logo, ala F-35. But planes like Gripen, Rafale or modern F-16 are quite good bets in any case, whereas single role squadrons dispatchment would consist on risky gambles about future operational needs don’t you think?

    • picard578 said

      “IMO I you’ve got attack planes on a forward base waiting for orders to blow up ennemy tanks, you can bet you’ll need them to intercept ennemy aircrafts, escort civilian planes, or do SAR, etc… Having several specialised aircrafts on said base would obviously limit capability for each possible mission too. Pilots would also either be specialised to one type of mission, or need to be qualified to fly several different types of fighters.”

      But you can have more aircraft. For cost of a single multirole fighter – which typically is nothing more than an air superiority fighter capable of carrying bombs and blowing up buildings – you can have an air superiority fighter plus a CAS fighter, providing far more versatility. Not to mention that pilots have to train, which means that aircraft should be easy to maintain and cheap to fly, and single-role aircraft, when properly designed, will be cheaper on both counts than multiroles.

      And even on multirole fighters, pilots tend to be specialized for one type of mission. In France e.g., single-seater Rafale pilots tend to focus on air superiority while twin seater crews focus on ground attack. So in effect you still have two groups of specialized aircraft. There are exceptions (single-seater pilots focusing on ground attack), but they’d still comparatively suck at what they train less at. In US, you have F-16C crews training for generalized ground attack (and a bit of air combat) and F-16J crews training for SEAD/DEAD. Aircraft themselves are also specialized, with one mission being primary and others an afterthought (Rafale and Gripen are primarily air superiority fighters, F-35 is primarily a ground attack aircraft).

      “Having several specialised aircrafts on said base would obviously limit capability for each possible mission too.”

      Depends. An aircraft designed for one type of ground attack missions can easily carry out other types as well. But I’m against designing aircraft for widely different types of missions (air superiority + ground attack, for example), as these mean compromises in primary mission and aircraft still won’t be able to really carry out its secondary mission as it should.

      “But planes like Gripen, Rafale or modern F-16 are quite good bets in any case, whereas single role squadrons dispatchment would consist on risky gambles about future operational needs don’t you think?”

      None of these can carry out effective close air support and battlefield interdiction. So since CAS pilots will have to train for ground attack anyway, and in specialized aircraft, why not leave them the whole spectrum of ground attack missions and leave air superiority to fighters designed for it?

      And considering lesser need for airbase maintenance and generally easier maintenance of single role fighters, you could easily afford two or three squadrons in place of one multirole.

      • vyse said

        “But you can have more aircraft. ”

        True, but any base has a limit of how much planes it can handle, so in any case chosing single-role way is mostly dividing that number by the number of types you want to operate. In the end each specialised squadron is only fraction of the number potential you have with full multi-role fleet, although as we both recognize it’s more efficient and lest costly.

        “None of these can carry out effective close air support and battlefield interdiction. So since CAS pilots will have to train for ground attack anyway, and in specialized aircraft, why not leave them the whole spectrum of ground attack missions and leave air superiority to fighters designed for it?”

        Yes you have a big point here. But CAS is very special case. Leaving it aside, the whole pannel of missions achievable with said multi-roles aircrafts (Gripen, Raffale, F-16…) is comprising almost all you need. In case of Raffale, you don’t even need to change anything bar weapons before switching to AtA type from AtG, or even drowning sea targets, performing recon, etc.

        This have a strong impact on strategy as it allows pertinent reactions in lots of possible scenarios, which means ennemy will struggle to put you in a situation where you can’t react.

        I’m not really arguing that multi-role is paramount, I mostly agrees with the core of your reasoning (especially cost/efficiency ratio). I just think it much less straightforward than you put it, because tactical flexibility suffers from that choice.

        • picard578 said

          “True, but any base has a limit of how much planes it can handle”

          Indeed. But generally speaking, single role aircraft can be made smaller, lighter and more resillient, so you can operate them off dirt strips or road bases, which reduces base maintenance costs. And for the most important roles (close air support and tactical transport) you don’t have any choice but to go single-role, meaning that multirole aircraft will be carrying out single role missions most of the time anyway.

          “Leaving it aside, the whole pannel of missions achievable with said multi-roles aircrafts (Gripen, Raffale, F-16…) is comprising almost all you need.”

          But the most important missions – close air support and battlefield interdiction – are left out. And I would not have very narrow specialization, but rather specialistic design for a number of roles.

          For example, take a look at roles that aircraft I have proposed can carry out:
          FLX: air superiority, bomber interception, air recon, standoff jamming, communications jamming
          ALX: close air support, battlefield interdiction, SEAD, DEAD, air interdiction, low-altitude strike, maritime strike, air control, standoff jamming, communications jamming
          OLX: air control, COIN ops, close air support, battlefield interdiction

          In these cases, secondary roles naturally flow from aircraft’s primary role. They all have similar training and design requirements, so there are few compromises. Therefore, each of these aircraft can afford to be smaller, lighter and less complex than “true” multirole aircraft, and still be far more effective at every single role due to similar / reinforcing design requirements for these missions. This means that they will be cheaper, easier to maintain and more survivable than multirole aircraft as well.

          Now compare this with multirole aircraft:

          F-18: bomber interception, maritime strike, SEAD, DEAD, air interdiction, aerial reconnaissance, air superiority
          F-35: low-altitude strike, SEAD, DEAD, air interdiction, standoff jamming, communications jamming
          Gripen: air superiority, bomber interception, air recon, air interdiction, SEAD, DEAD, low-altitude strike, maritime strike, standoff jamming, communications jamming
          Rafale: air superiority, bomber interception, air recon, SEAD, DEAD, air interdiction, low-altitude strike, maritime strike, standoff jamming, communications jamming, nuclear strike
          Typhoon: bomber interception, air superiority, air recon, air interdiction, SEAD, DEAD, maritime strike, standoff jamming, communications jamming

          FLX would cost ~40 million USD, ALX ~10 million USD and OLX ~5 million USD, for a total of 55 million USD. Even with additional stuff (pods etc.) it won’t go past 70 million USD.
          Gripen C costs 45 million USD but is far more limited than FLX in terms of capability. F-18E costs 70 million USD, Rafale C costs 90 million USD, EF2000 costs 130 million USD, F-35A costs 145 million USD.
          Gripen NG, which would bring Gripen closer to the FLX in terms of capability (when it comes to air combat, anyway), may have unit flyaway cost of anywhere between 50 million and 120 million USD.

          In other words, for price of a single F-16C you can have 1 FLX, 1 ALX and 1 OLX. For price of a Rafale, you can have 1 FLX, 3 ALX and 4 OLX. For price of an EF2000, you can have 2 FLX, 3 ALX and 4 OLX, and for price of an F-35A you can have 2 FLX, 5 ALX and 3 OLX or 3 FLX, 2 ALX and 1 OLX. You get more aircraft, more sorties per aircraft and better performance in any single mission. I do agree that having twin-seater FLX carry out ground attack roles could be a good thing (superior speed and agility would be a bonus in strike and SEAD/DEAD), but a single-seater FLX should always stay single-role.

          Possibly more important issue is that of pilot training. Good pilots are more important than good aircraft (or numbers). Aside from a simpler and cheaper to operate aircraft providing more opportunities for training, having pilots train for a number of closely related roles will greatly improve their ability to carry out these roles when compared to pilots who train for a number of disparate roles.

          Further, if you take a look at current force structure of “multirole” aircraft, they lack ability to carry out close air support, battlefield interdiction and COIN warfare. For these missions, you still need specialized aircraft… which means that either way, you will need a minimum of two different tactical aircraft types, just with my proposals.

          And I’d say that the entire “easier logistics”, “standardization”, etc. BS falls flat on its face when you take a look at how many different aircraft most Western air forces operate. They carry out standardization where it shouldn’t be done – in combat aircraft – while leaving around dozens of types of transport, AWACS, AEW etc. aircraft with significantly overlapping characteristics and missions.

          “I just think it much less straightforward than you put it, because tactical flexibility suffers from that choice.”

          It never is completely straightforward. Finding good balance is the hardest part.

  4. Chris said

    The other issue may be “failure by design”.

    If you think about it, a successful aircraft would be a nightmare for a contractor.

    1. No serious problems to fix
    2. Cheap aircraft (probably very low margins per plane) – only somewhat helped by lower volumes
    3. Only real profits would be spare parts and maybe maintenance
    4. Easy to maintain means nothing like complex hangars
    5. Successful combat performance would mean fewer future defense expenditures

    I suppose for the defense industry, the system is “working”.

    • picard578 said

      Indeed it is. Now, military could easily insist on a proper aircraft, and not buy aircraft until proper testing is completed, but generals looking for jobs in defense industry will not accept that.

    • Chris said

      Economists have a name for this – perverse incentive.

      Basically the benefits for milking the existing system are better than playing it honest – even if it would mean other possibilities. I suppose the fact that the defense industry has consolidated means that the “survivors” are the ones who are most adept at playing the system.

  5. Felix said

    What’s your view on the russian planes like mig29 – 35 are they cost effective or “adjusted” by the government?

    • picard578 said

      Cost-effective is a relative thing, but I’d say that MiG-29 variants are OK. Not too good thanks to relatively large size, twin engined configuration and inefficient engines (early models), especially when combined with short range, but far better than, say, F-35 or most other stealth fighters.

  6. Chris said

    The latest report is actually quite funny:

    Apparently the F-22 is only just testing the ability to get a Helmet Mounted sight and the AIM-9X.

    Kind of scary if you think about it. They spent so much money on the fighter and missed quite a few major details. It makes you go, what else was overlooked? Pilot training is a known.

    • picard578 said

      It has no IRST. Its IR/UV MAWS can be used as IRST in theory (just as EO DAS and DDM NG), but it will be range-limited.

      And they didn’t “miss” these details, IRST and HMD were both deleted to “save money”.

    • Chris said

      True that.

      It is the classic “penny-wise” and “pound foolish”. Logically, if one spends so much on the aircraft, I think it would be logical that it’s a Might as well” develop the best array of sensors possible – including IRST.

      The disturbing thing is that this is not an expensive technology to be investing huge sums of money in either.

    • Chris said

      Of course, in this case, it’s not even penny wise to be neglecting IRST.

  7. PassTheAmmo said

    Picard578, speaking of the necessity of certain features on future warplanes, what do you think of the usefulness of swing-wings in modern warplane design? I’ve heard that the F-18’s combat payload isn’t as much as the F-14’s, given that the F-18 doesn’t use swing-wings like the F-14 did.

    • picard578 said

      Swing wing’s primary advantage is fuel economy during subsonic cruise while allowing high maximum speed. However, it results in low optimum cruise speed (M 0,7 vs M 0,9 for a delta), increasing vulnerability to surprise attacks. It also increases mechanical complexity.

    • Chris said

      Another advantage is that they need shorter runways.

      The big problems are:

      – Weight (about 10-15% penalty here)
      – Will cost more to build than other wings
      – Lower flight to maintenance ratios

      I would argue it’s not worth it in most cases.

    • Chris said

      Also add I don’t think swing wings can hold much on their wings – fuel or missiles. So maybe lower fuel fraction too?

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