Aircraft performance parameters quick look

aircraft performance parameters quick look wing loading:
Rafale C: 276 kg/m2
Rafale M: 288 kg/m2
Typhoon: 291 kg/m2
Gripen C: 293 km2
F-22: 314 kg/m2
F-35A: 428 kg/m2
F-35B: 434 kg/m2
F-35C: 338 kg/m2
F-15C: 278 kg/m2
F-16A: 339 kg/m2
F-16C: 392 kg/m2
F-18E: 403 kg/m2
Su-27: 324 kg/m2
Su-35: 377 kg/m2
Harrier II GR-7: 352 kg/m2
Harrier II Plus: 393 kg/m2
J-35J Draken: 183 kg/m2
Tornado ADV: 711 kg/m2
FLX: 259 kg/m2

span loading:
Rafale C: 1.166 kg/m
Rafale M: 1.215 kg/m
Typhoon: 1.329 kg/m
Gripen C: 1.046 kg/m
F-22: 1.813 kg/m
F-35A: 1.707 kg/m
F-35B: 1.733 kg/m
F-35C: 1.604 kg/m
F-15C: 1.205 kg/m
F-16A: 947 kg/m
F-16C: 1.098 kg/m
F-18E: 1.375 kg/m
Su-27: 1.367 kg/m
Su-35: 1.528 kg/m
Harrier II GR-7: 860 kg/m
Harrier II Plus: 960 kg/m
J-35J Draken: 954 kg/m
Tornado ADV: 1.359 kg/m
FLX: 989 kg/m

thrust-to-weight ratio:
Rafale C: 1,197
Rafale M: 1,14
Typhoon: 1,26
Gripen C: 0,93
F-22: 1,29
F-35A: 1,07
F-35B: 1,003
F-35C: 0,93
F-15C: 1,15
F-16A: 1,146
F-16C: 1,186
F-18E: 1,07
Su-27: 1,24
Su-35: 1,24
Harrier II GR-7: 1,24
Harrier II Plus: 1,201
J-35J Draken: 0,89
Tornado ADV: 0,79
FLX: 1,247

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22 thoughts on “Aircraft performance parameters quick look

  1. Is span loading that important? If I recall correctly, higher span loading means stronger vorticies.

    Actually, could you list the FLX stats as well for comparison?

  2. It’s pretty interesting to see that the FLX dominates most of these categories.

    It’s only span loading that the F-16 and the Draken are slightly better (and a modern YF-16 I’d imagine would work even better). The Harrier is not really competitive as an air superiority fighter so it doesn’t count here.

    Two interesting observations:
    – Amongst the real world fighters, the Rafale is probably the best
    – With a better engine, the specs suggest the Saab Draken would be a good fighter with most of the advantages of the FLX

    • OF course there are other flaws with the Draken (rear visibility isn’t too good), but everything else looks solid – provided it had a better engine.

      The main weight savings of the FLX seems to be the radar deletion and the exclusion of unneeded (and often costly) avionics.

    • “It’s pretty interesting to see that the FLX dominates most of these categories.”

      Interesting but not really surprising considering that the FLX, F-16A and J-35 are the only purpose-designed air superiority fighters on the list, and the FLX is far newer and more advanced in terms of aerodynamic configuration and materials used.

      “It’s only span loading that the F-16 and the Draken are slightly better (and a modern YF-16 I’d imagine would work even better).”

      Correct, it was a conscious decision on my part – lower wing sweep and thus higher wing span would improve span loading and takeoff/landing performance. However, it would also limit the basing ability (FLX has 20 cm larger wing span than Gripen C as it is, and for optimal road basing capability wing span should be less than 8,75 meters), as well as reduce cruise speed and acceleration. Further, wings that have cca 50* wing sweep have some beneficial characteristics when it comes to air flow reattachment during high-AoA maneuvers. From my FLX article:

      >>Delta wing allows good lift-to-weight ratio due to the large surface area and relatively low weight of the wing itself. One of reasons for its good lift production is that large part of the wing area is near the wing root, and is thus less affected by the spanwise loss of lift which occurs towards the wing tips. Nonslender delta wings (<55* wing sweep) allow for air flow reattachment even after breakdown reaches the apex of the wing, however vortex generating surfaces (LERX and close-coupled canards) are required for flow reattachment at high angles of attack in the post-stall region. Flexible wing can increase lift and delay stall compared to the nonflexible wing of the same geometry. This effect is helped by vibrations which promote reattachment of the shear layer and thus lift enhancement. Moderate wing sweep angles (around 50°) help formation of semi-open separation bubbles, helping flow reattachment.<>Lower-swept wing (44-45*) is less affected by negative effects of downwash on wing lift than higher-swept wings (60*), and presence of the canard may cause it to produce significant amounts of the side-edge vortex lift on the low swept wing.<=45* and aspect ratio of <3,5. FLX has wing sweep of 50* and aspect ratio of 2,23. Compare this to Rafale's wing sweep of 48* and aspect ratio of 2,55 (note that when compared to Mirage, Rafale has reduced wing sweep (48* vs 58*) and increased aspect ratio (2,55 vs 2,03) specifically for purposes of increased maneuverability). Typhoon has wing sweep of 53* and aspect ratio of 2,4, Gripen has wing sweep of 45* and aspect ratio of 2,35, Draken has aspect ratio of 1,8.

      "– Amongst the real world fighters, the Rafale is probably the best"

      Agreed.

      "– With a better engine, the specs suggest the Saab Draken would be a good fighter with most of the advantages of the FLX"

      Better engine and stronger composite airframe. It might be somewhat let down by its low aspect ratio wing, and it has issues with cockpit visibility and larger size. But then again, compound delta might well be the second best thing after close coupled canards when it comes to maneuverability – note that both Rafale and Typhoon were originally suposed to have compund delta wings, but it was changed to straight delta for sake of simpler production and maintenance. Rafale does have LERX, which offers mostly same advantages as the compound delta configuration, though not as pronounced.

      "The main weight savings of the FLX seems to be the radar deletion and the exclusion of unneeded (and often costly) avionics."

      Yes and no. Weight savings are as follows:
      1) exclusion of air-to-ground avionics (radar, some computers) and some other unnecessary luxuries (canopy actuators, for example)
      2) lighter airframe due to lesser need for heavy loads (there are only 3 heavy hardpoints for fuel tanks, compared to 5 heavy hardpoints on Gripen – 3 wet and 2 exclusively for air-to-ground stores, and Gripen also has an additional hardpoint for the targeting pod.) as well as more advanced composite materials and manufacturing process
      3) more compact design

  3. Yeah I can see the road mobility being the issue.

    The only way I could see it being solved partially is folding wings like this Su-33:

    But that adds mass and complexity, although it might allow more aircraft on an aircraft carrier. Something like this might be of use on a carrier based FLX though.

    It’d be interesting to see how the “cranked arrow” delta affects speed and handling characteristics. I wonder if a compound delta could be pared with canards.

    But yes, I agree that the composite technology is the main savings that I neglected – that and the hardpoints (no air to ground needs for bombing and no needs to super heavy missiles). I have wondered for the French, why not make an air to air variant without the heavier hardpoints?

    • “But that adds mass and complexity, although it might allow more aircraft on an aircraft carrier. Something like this might be of use on a carrier based FLX though.”

      I’d rather avoid it if at all possible. Not only does it add mass and complexity, it also limits maneuvering capability – IIRC, folding wings are one of reasons why carrier-borne F-18s and Su-33s cannot achieve more than 7,33 g. FLX has strong enough airframe that even a carrier version can achieve 9 g, but I doubt it would be possible with folding wings.

      “It’d be interesting to see how the “cranked arrow” delta affects speed and handling characteristics. I wonder if a compound delta could be pared with canards.”

      Compound sweep (cranked arrow) delta basically has benefits of a huge LERX: high inboard sweep promotes formation of vortices at high angles of attack, reduces wave drag and also moves most of the wing out of the shock cone even once it passes wing tip. Low outboard sweep reduces span loading and thus induced drag. However, both Rafale and Typhoon switched from compound delta to simple delta in order to simplify production and maintenance, though Rafale emulates some of advantages of compound delta with its LERX (note that in terms of cruise performance the FLX has an effective wing sweep of 54* despite nominal wing sweep of 50* due to its LERX).

      “I have wondered for the French, why not make an air to air variant without the heavier hardpoints?”

      Rafale was supposed to provide savings by replacing many different aircraft with a common airframe. Making an exclusive air-to-air version of what is already air-to-ground capable air superiority fighter would mean different production process, low parts commonality when it comes to airframe at least (different, lighter wings, no targeting pod hardpoints under the intakes etc.), and cost wouldn’t be reduced by too much (maybe 25%, since size would not drop and size was actually dictated by air-to-ground requirements).

    • I’d rather avoid it if at all possible. Not only does it add mass and complexity, it also limits maneuvering capability – IIRC, folding wings are one of reasons why carrier-borne F-18s and Su-33s cannot achieve more than 7,33 g. FLX has strong enough airframe that even a carrier version can achieve 9 g, but I doubt it would be possible with folding wings.

      That’s the worry. Against this, the only potential advantage I could see with folding wings is the ability to add more aircraft into a carrier, but yeah the ~7G limit (versus 9G) is a pretty big drawback.

      Compound sweep (cranked arrow) delta basically has benefits of a huge LERX: high inboard sweep promotes formation of vortices at high angles of attack, reduces wave drag and also moves most of the wing out of the shock cone even once it passes wing tip. Low outboard sweep reduces span loading and thus induced drag. However, both Rafale and Typhoon switched from compound delta to simple delta in order to simplify production and maintenance, though Rafale emulates some of advantages of compound delta with its LERX (note that in terms of cruise performance the FLX has an effective wing sweep of 54* despite nominal wing sweep of 50* due to its LERX).

      I suppose that was probably due to costs.

      I’d imagine a cranked arrow design (possibly with canards) would be a “money no object” sort of thing that would be expensive, but not much better than the leading edge normal delta. The other question becomes how much more in terms of cost and maintenance it would have been. The other is how good the performance gain would be.

      That being said, the Eurofighter seems to be getting more costly with each new tranche.

      Rafale was supposed to provide savings by replacing many different aircraft with a common airframe. Making an exclusive air-to-air version of what is already air-to-ground capable air superiority fighter would mean different production process, low parts commonality when it comes to airframe at least (different, lighter wings, no targeting pod hardpoints under the intakes etc.), and cost wouldn’t be reduced by too much (maybe 25%, since size would not drop and size was actually dictated by air-to-ground requirements).

      It’s a pity – 2 airframes would have worked better.

      I’ve been thinking about maintenance. F-22 availability was only around ~56% in 2011. GAO wants 70.6%, which did not seem to be possible:
      http://www.gao.gov/products/GAO-14-425

      Whether it will achieve that is open for debate.

      The issue I see is that a typical fighter like the F-22 today is on a base with lots of technicians, spare parts, and what amount to ideal conditions.

      War time conditions are not like that at all. Disruptions in supply chains, spare parts shortages, and rough hangars are the norm. What will that do to the already bad reliability?

      Also, somewhat off topic, but I believe that a defense reformer, Everest E. Riccioni has just passed away. I’m not 100% sure that this is the Everest Riccioni, but check this out:
      http://www.tributes.com/obituary/show/Everest-Ernesto-Riccioni-102391364

      I’ve been trying to find his full report:
      MILITARY ANALYSIS of the USAF F–22 RAPTOR ACQUISTION, ITS OPERATIONAL FUTURE — A NATIONAL TRAGIC
      COMEDY by Col. Riccioni, 2004, 66 pages

      There’s the short 25 page report that he wrote:
      DESCRIPTION
      OF
      OUR FAILING DEFENSE ACQUSITION
      SYSTEM
      AS EXEMPLIFIED BY THE
      HISTORY, NATURE AND ANALYSIS
      0F THE
      USAF F–22 RAPTOR PROGRAM
      A NATIONAL TRAGEDY — MILITARY AND ECONOMIC

      Which can be found online, but the full report seems to be gone.

      • “I’d imagine a cranked arrow design (possibly with canards) would be a “money no object” sort of thing that would be expensive”

        More expensive and possibly more maintenance intensive as well.

        “That being said, the Eurofighter seems to be getting more costly with each new tranche. ”

        Most modern aircraft do. Rafale, Gripen, F-16…

        “What will that do to the already bad reliability?”

        Reduce it. Significantly.

      • The issue here is that the original justification for the F-35 was the VTOL in forward bases, but if that’s not possible, then the rationale loses all justification.

        • Eh, F-35 will never operate from forward bases in any meaningful way. USMC wanted STOVL so that they can have some air power on their assault ships if Navy decides to pull Guadalcanal and leave them without air support. Only problem is that USMC have their priorities wrong – what they need is not STOVL aircraft to operate from amphibious ships but dirt strip STOL fighter to operate from forward shore air fields.

  4. You know I’ve been thinking – the next fighter aircraft will likely prove even more expensive and complex than the F-22 and JSF.

    Back when the airforce wanted to replace the F-111, they came up with a clone which became the FX. There probably will not be a set of defense reformers this time to save the day.

    • “Do the wing loading stats include body lift?”

      Yes and no. Take a look at my air superiority fighter proposal to see how wing loading is calculated.

      • So the body lift is an estimate provided by extending the wing area directly into the fuselage?

        What I don’t understand is the bottom picture here: http://img229.imageshack.us/img229/9932/wingareahw5.jpg
        I understand how that works with the top picture simply extends the leading and trailing edge until they meet the opposite wing’s leading and trailing edge respectively, but the bottom picture is basically a parallelogram.

        • “So the body lift is an estimate provided by extending the wing area directly into the fuselage?”

          No. That is how wing loading is calculated. Lifting area depends on aerodynamic configuration and flight conditions. That being said, classic wing loading calculation accounts for most of the body lift, but does not account for lift improvement by high lift devices such as strakes, LERX and close-coupled canards. Consequently, in F-35 vs Rafale/Gripen debates, “wing loading is not indicative of turning ability” argument actually works against the F-35 and not in its favor since canards can increase wing lift by as much 30-35% (again, depending on configuration; IIRC, it is ~30% in Rafale), which is more than the F-35s stealthy “chimes” can hope to achieve.

          “What I don’t understand is the bottom picture here:”

          There is still a “wing” in that picture, including leading and trailling edges. Actual wings are very small, but main point is that “wing area” in there encompasses empty area between the tails as well.

      • Out of curiosity, why are chines so ineffective? I suppose that they are ‘static’ and cannot change their position whereas canards can change AoA and are thus ‘dynamic’. The F-35 looks to have a decent amount of LERX.
        Using the good old ruler on the screen and some math I find that the F-35 (not including LERX) has a wing area of 460 ft^2 and wing loading at 40,000 lbs is 87 lbs/ft^2. With a wing area of 300 ft^2 and a weight of 23,000 lbs, the F-16C-50 has a comfortable wing loading of 77 lbs/ft^2.

        • “Out of curiosity, why are chines so ineffective? I suppose that they are ‘static’ and cannot change their position whereas canards can change AoA and are thus ‘dynamic’. The F-35 looks to have a decent amount of LERX.”

          For one, F-35s “chines” are not full LERX, extension covers only foremost third or so of the air intake side and does not extend all the way to the wing. There is also adverse interaction between chines and wing fillet (a mini-LERX, basically) which causes vortices to burst relatively early on:

          In general comparison, LERX has the advantage in cruise flight in that it modifies the Mach line and increases cruise speed. In turning flight, it creates two sets of vortices. However, unlike canards, LERX cannot adjust itself to flight conditions; it is fixed. Canards, on the other hand, can be set for maximum lift enhancement, maximum lift-to-drag ratio or minimum drag. Typically, they are configured for maximum lift during first second or so of the turn, and minimum drag later on. Canards can also be better adjusted for covering wing with vortex flows – whereas LERX typically only energizes inboard portion of the wing and thus helps lift, canards energize inboard and outboard portions of the wing, helping both lift and wing response to aeliron input, which has the effect of increasing roll onset rate and consequently transient performance.

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