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How to reduce fighter aircraft cost

Discussion in 'The Big Adda' started by Picard, Jun 3, 2015.

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  1. Picard

    Picard Lt. Colonel RESEARCHER

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    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 their respective countries' air forces. 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.
     
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  2. positron

    positron Captain FULL MEMBER

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    I did not read it fully, but then just stopped at where the post became illogical, keep the plane single role? by this logic for the various roles, you might end up making different planes and hence a different plane for strike, a different plane for CAS, a different plane for air superiority, you might end up making the air force unworkable

    The planes should be as per the requirement, fr example for CAS, or interception etc, Single engine planes are good, cheap to build, easy to maintain etc etc, but for deep role and for heavy strike, one needs twin engine planes that can carry both, fuel and load, and still have the ability to get in fast, send its A2G missiles on the way, and fly out of trouble even fighting it. And for this deep strike role, single engine will compromise on either or both Range and war load.
     
  3. Picard

    Picard Lt. Colonel RESEARCHER

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    Multirole aircraft are completely incapable of performing CAS duties, so you still need a dedicated CAS platform. Once you have a CAS platform, you can have it carry out other ground attack missions as necessary, but you should never have an air superiority design carry out ground attack.

    True. But can you find a single war where deep strike was useful (and achieved something that battlefield interdiction could not)?
     
  4. abhitej

    abhitej Captain SENIOR MEMBER

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    I agree with you. Multirole fighter is a big scam. You end up with substandard fighter not good for any role. I like Russian approach towards fighter. Separate fighter for separate role.
     
  5. positron

    positron Captain FULL MEMBER

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    Presently if you see with the technology available, any good plane can perform CAS role, CAS meant providing air support and dropping ordanance precisely so that the troop even at company can be supported. During WW2 it was the Stuka and later it was the A-10/Su-25, but these planes in a way were limited by the technology, what was the best missile that A-10 had? Maverick missile, the Su-25 relied more on the unguided rockets which were effective but inaccurate but they got the job done. But on other hand you have missiles like Brimstone, which can be dropped from say 10 kms away and provide more precise targetting of enemy positions. There is no need for the pilots to fly low, there are sensors and camera on drones that can see very clearly from miles away and even identify the person by face detection. For CAS it all runs down to,
    PLANE that can loiter for a long time and support troops.
    Weapons that can be targeted accurately and have deadly firepower, which modern missiles like Brimstone or GPS guided bomb can do,
    Tell me my friend, if you can take down a target with an accurate missile and help your troops move in, would your troops want a plane with 4 rocket pods that keep on blasting the hell out of area? Perhaps yes, there is one advantage of this inaccurate firepower, it can in a way break the enemy morale, but in case the enemy is well experienced and get over the inaccurate rocket attack, and if your land troops follow up then they are dead meat. So in a way the rocket launching CAS plane might not really fulfill its role
     
  6. randomradio

    randomradio Colonel REGISTERED

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    Is that why PAK FA is multirole?
     
  7. vstol jockey

    vstol jockey Colonel MILITARY STRATEGIST

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    Keeping it role specific allows you to optimize the avionics suite for that specific role and you use same airframe with different avionics suite for different role. the aircombat has become so advanced that it is not possible for one single pilot to handle all the avionics and weapons of a multirole aircraft. I am also for role specific aircraft rather than multirole platforms.
    take a case wherein a strike force of multirole aircraft goes into combat with swing role weapons load comprising bombs and A2A missiles. The moment this strike gets bounced, they will have to drop their bombload to get to best agility. This means the end of strike role and all the bombs vl be dropped as deadload.
    But take the case of IAF in kargil war. They used Mig-29 escorts for M2K operating in strike role and the M2K were able to deliver their load uninterrupted. IAF uses same tactics for Jags also. We have a system of escort commander and strike commander. The Escorted strike does not terminate their mission even if bounced as the escorts are there to do the job of taking on enemy interceptors. Such an escorted strike force has much higher probability of achieving their mission goals compared to a strike done by multirole aircraft.
     
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  8. randomradio

    randomradio Colonel REGISTERED

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    Single role aircraft have become a luxury now. Or it is the best.

    Right now, they only develop multirole aircraft with role specific armaments. So a Tejas with R-77s will escort a Tejas carrying Griffins.
     
  9. positron

    positron Captain FULL MEMBER

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    I do agree that keeping it role specific allows you to optimise avionic suite, but then the trade off would be to buy a different plane that can handle a different role, for example Jaguar for Strike and MiG-29 to escort it (just an example here and hope people do not go to specifics) But then the problems with this is
    a) Spares management, you have to manage spares of two different planes.
    b) Pilot training, though for a particular role the pilots are specially trained, but for two different planes the training will be entirely different.
    c) Needing more planes to do different jobs, for example if its say Su-30 MKI it can handle both Deep strike, air dominance, reconaissance and many other roles and even interception if required (though this is more in for Tejas) but then having role specific planes you wll end up with more planning and keep the planes ready, for those roles. See the case of Mirage 2000, they were never expected to be in action in Kargil, the role specific Jaguar could not work there. But if it was a plane say like MiG-29 (in present form) or Su-30 MKI they would be able to complete the mission without needing planes from another squadron to fly escort.
     
  10. vstol jockey

    vstol jockey Colonel MILITARY STRATEGIST

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    My personal exp is to have a pilot who is master in his field rather than one who is " jack of all trades and master of none". All this talk of sensor fusion can still not overcome the human limitations.
     
  11. vstol jockey

    vstol jockey Colonel MILITARY STRATEGIST

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    Pls read my post again in total. I have stated that we shud use the same airframe for different roles with different set of avionics. This will solve the problem of spares and pilot training. Its like having a Rafale for A2A role only, another Rafale for A2G only and another Rafale for Nuke strikes only. Instead of having one single Rafale for every thing.
     
  12. randomradio

    randomradio Colonel REGISTERED

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    I believe I have said the same. But at the same time I think all multirole pilots are trained in all missions. Just that some pilots get extra training in some missions. I think what's more important is allowing pilots to fly more. 100-150 hours every year is not enough even for small aircraft.

    Anyway, sensor fusion has done a lot. Rafale pilots say they do 5, 6 hour briefings on their aircraft itself without having to land. Kinda like how smartphones have become.
     
  13. abhitej

    abhitej Captain SENIOR MEMBER

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    It is an air superiority fighter. They are making another bomber PAK DA.They make it in pairs. Su-27 & Su-24. Now Su-35 & Su-34. Separate fighter for air superiority & strike.
     
    Last edited: Jun 3, 2015
  14. vstol jockey

    vstol jockey Colonel MILITARY STRATEGIST

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    Multirole pilots are the topmost layer of fighter stream. they are a combination of strike and interceptor stream. This shud tell you how demanding it becomes to operate a multirole aircraft.
     
  15. abhitej

    abhitej Captain SENIOR MEMBER

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    CAS with missiles is costly. Attack helicopters are better for this role.
     
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