STOBAR aircraft Ski-jump performance (SU-33/J-15)

Discussion in 'World Armed Forces' started by Bltizo, Sep 1, 2016.

  1. Bltizo
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    Bltizo Senior Member

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    A few years back in 2012 we had a great translation of a series of magazine scans that seemed to show in quite a bit of detail about how much Su-33 could take off from a Kuznetsov class carrier's ski jump at different positions under different conditions.

    Unfortunately, the series of posts were lost on SDF because apparently the carrier thread at the time accidentally got deleted, but fortunately the posts (translation done by no_name, at the time) were cross posted to a different forum, here: http://warships1discussionboards.yuku.com/topic/19631/Slowest-possible-STOBAR-carrier#.V8isqZh97IU

    I'm going to repost the entire thing here on SDF, in a dedicated thread for ease of reference in future (goodness knows I've tried to find this information before, in the past on many an occasion), and also so it can turn up easily in future when one puts in the right search terms.


    舰载武器军事评论第10期,《苏-33/歼-15舰载战斗机航母起飞性能研究》一文,详细地给出了苏-33/歼-15的性能和使用方式,当发动机推力是12800公斤时,零风速,长点,无任何飞行轨迹下降,32.8吨, 最大38吨,短点,无任何飞行轨迹下降,27吨,最大28.2吨,25节甲板风,110米以上的滑跑距离, 苏-33/中秋以最大重量32000千克可以很轻松地直接起飞,在有25节甲板风的情况下,苏-33/中秋可以在1、2号起飞位置,110米的滑跑距离提供类似于无风状态195米的3号起飞位置同样的起飞性能 ,这样的起飞距离和起飞效果与蒸汽弹射器提供的能力非常接近,如果发动机推力增加到14000公斤以上,将 完胜蒸气弹弓。
    文中还详细地分析了特殊情况及安全余度,包括推力损失、单发安全、单发起飞,以及这些情况对舰载机实际在航 母上使用时所产生的影响,并给出了苏33/中秋在航母上初级飞行员作训模式、正常作训模式、1、2号位置的紧急起飞模式下的使用起飞重量 范围以及苏-33/中秋的几个典型作战状态等内容。

    Assuming 12800Kg thrust, 0 knot headwind: From long take-off point can take-off with 32.8 tonnes, maximum 38 tonnes. From short take-off point can take-off with 27 tonnes, 28.2 tonnes max. At 25knots headwind, Su-33 can easily take-off at max load of 32000kg from 110m. Taking off from 110m under 25 knots headwind gives the same condition as taking off from 195m under no wind. (so the extra 85m length translates to 25 knots more speed). This kind of take-off capability is very close to that provided by conventional steam catapult. IF engine thrust can be improved to 14000kg the performance will be superior to steam catapult.

    1.jpg


    2.jpg


    Right column top part: Some basic combat loadings for Su-33 fighter jet.

    Su-33 fighter was developed 20 years ago, its electronics was outdated, lacking multirole capabilities, and lacking weapons customised specifically for the aircraft. Since 2010, Russia has embarked on a mid life upgrade and modernising program for its remaining Su-33s in service, adding the capability to fire R-77 medium range AAM, KH-65/KH-35 multirole anti-ship/anti-ground cruise missiles, and can also carry LGB-500/1500 laser guided bombs. (and the aiming pod for it)

    1.
    TOW : 26000kg
    Fuel : 5700KG
    Payload : 4 R-73 + 4 R-77.
    Range : 1900km.
    Flight time : 2hr 31 min.
    Combat radius : 660Km
    Combat time (on station time?) at 250km is 1hr 10 min.

    2.
    TOW : 27000kg
    Fuel : 6300kg fuel
    Payload : 4 R-73 + 2 R-77 + 1 KH-65E
    Range : 2100km
    Flight time : 2hr 50min
    Combat radius : 710km

    3.
    TOW : 30500kg
    Fuel : 9300kg fuel
    Payload : 4 R-73 + 8 R-77
    Range : 3000km
    Flight time : 4hr 23min
    Combat radius : 1280km
    Combat time (on station time?) is 2hr 30min at 400km

    4.
    TOW : 30500kg
    Fuel : 5700kg
    Payload : 22 x 250kg bombs i.e. 5500kg
    Range : 1700km
    Flight time : 2hr 3min
    Combat radius : 700km

    5.
    TOW : 31900kg
    Fuel : 9300kg
    Payload : 4 R-73 + 2 R-77 + 4 KH-31P
    Range : 3000km
    Flight time : 4hr 40min
    Combat radius : 1220km

    6.
    TOW : 31400kg
    Fuel : 9300kg
    Payload : 4 R-73 + 2 LGB-500 + 1 LGB-1500 + 1 pod
    Range : 2900km
    Flight Time : 4hr 2min
    Combat radius : 1250km
    ===============

    Right column bottom part:

    Basic stats for Su-33/J-15

    length: 21.94m
    wing span:14.7m
    height:5.93m
    wing area:62 m^2
    empty weight:18400kg
    standard fuel capacity:5700kg
    maximum internal fuel capacity:9300kg
    maximum TOW:32800kg

    take-off speed:240-302 km/h (airport condition)
    maximum landing weight:26600kg
    normal landing weight:23300kg
    landing speed:220-260km/h (airport condition)
    maximum flight height:17000m
    maximum speed:Mach 2.13
    maximum climb rate:325m/sec
    Maximum g:8g/-3g
    hardpoints:12
    maximum external carrying weight:8000/6500kg
    parking width:7.8m
    engines:2*AL-31F-3
    Maximum thrust:2*7600kg, 2*12800kg with afterburner


    Continued below...
     
  2. Bltizo
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    Bltizo Senior Member

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    Continued...

    3.jpg
    4.jpg


    ^^^Under normal take-off conditions, a TOW of 1000kg above or below dictated limit do not give appreciable difference to take-off performance.

    At 0 knot headwind. Take-off from the short position 1,2 places greater restriction on TOW. When TOW reaches 27000kg, a inflection point can be clearly felt during the take-off profile, but there is no drop in altitude.

    This means that 27000kg TOW is acceptable and normal from pos. 1,2 under no headwind conditions.

    At 28200kg, there will be drop in altitude during the take-off profile, with the lowest point at 22.4m

    Normal take-off weight of su-33 is about 26.6 tonnes, so it can take-off from position 1,2 under any condition.

    (Note that this translates to an Su-33 carrying 4 R-73 and 4 R-77 missiles, with on station time of 1hr 10 min at 250km, basically in fleet defense role. This means that Su-33 can be scrambled from the short take-off positions under any wind conditions to respond to air-borne threats.)

    5.jpg

    ^^^A question of interest is the weight limit for a plane to be able to take-off from the 195m position with the help of the 15degrees incline.

    Modern Jet fighters undergo upgrades every 5-10 years, wich invariable translates to weight increases. For US carriers, the catapults and lifts are the deciding factor on the upper limit of aircraft weight. Many planes becomes disqualified due to weight, such as the F111B (over 34 tonnes) and the A-12 avenger (34-36 tonnes).

    The Soviet Su-33KUB twin seated fighter-bomber weights in at 38 tonnes. This is a weight not seen by US carrier planes. The A-5 was the nightmare of US carrier weighting in at 34-36 tonnes. The yak-44e in planning also reached 38 tonnes. Can these planes really take-off from carriers?

    From the 3rd take-off position at 195m, under 0 airspeed, Su-33 can still take-off with 35000kg weight with no dip in take-off profile. On leaving the bow of the ship the plane reaches a speed of 179km/h, reaching the apex height of 30m after 4 seconds, and glides for 6 seconds more before recovery at 312km/h

    At 38000kg, the take-off profile is an inverted s shape, with maximum point at 27.4m and minimum height of 20.2m. A recovery glide time of 11 secs and recover speed of 400km/h.

    6.jpg
    7.jpg

    ^^^European carriers tends to have lower top speed. British, Italian manages 28 knots max, and the new CVF only 26 knots. For american carriers propulsion power is not an issue, and their speed all exceed 30 knots, even reaching 33 knots max. Soviet carrier max speed is also over 30 knots. Naval aviation tend to set the useable maximum wind speed over flight deck at 25 knots.

    Normally carriers should be able to maintain a speed of 28 knots, so even if travelling with medium tail wind one can still ensure a headwind of no less than 25 knots.

    25 knots headwind and above 110m of runway to end of skip-jump will still allow a 32000kg TOW Su-33 to take-off easily. Glide time (I'm assuming this is the time that the pilot has to wait for the plane to gather speed before he can pull up?) of less than 5 seconds, and climb rate always above 2m/sec.

    When using 105m of runway length with the above conditions, the plane suffers no dip in its take-off profile, but there is a 3 second interval in which it will be flying almost level.

    At 95m the flight-profile still satisfies safety requirements, and can be used as the minimum take-off distance reference.

    (So this means that for the same take-off position there can be some slight variations on take-off diatance, as long as the blast deflector can safely block the back wash?)

    Headwind is a useful aid. At 25 knots, Su-33 can take-off from position 1,2 (110m) with the same effect as taking-off from position 3 (195m) under no wind condition.

    This kind of take-off distance and effect is competitive to the abilitiy provided by catapult launch. Some older catapults, like the C-13 from the 70's, may not even provide as much TOW.
     
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  3. Bltizo
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    Bltizo Senior Member

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    Continued....

    8.jpg
    9.jpg

    ^^^Also talking about taking off with one engine (now you see the importance of a twin engine carrier plane)

    Su-33 cannot take-off from any possible position with one engine under no headwind. At 25 knots, from the longest 195m take-off position 3, it may be possible if:

    under 22300kg there will be no dip in take-off profile.

    22300-23500kg there will be dip, but plane can pull up naturally before minimum safety height of 20m.

    About crew Training:

    1. Pilot needs about 50 take-off and landing experience on the carrier to complete the last stage of flight training.

    Elementary flight crew training starts under the conditions listed for single engine take-offs (NOT that they take-off with one engine (!), but that they start from take-off position 3 and with 25 knot headwind available)

    First 10 flights - TOW within 22300kg, 25 knot headwind, no external weapons load. 3500kg fuel, of which 2500kg can be used to simulate a 55min 800km flight, or one take off, 4 approach towards airspace around the carrier, 4 touch and goes, and one arrested landing.

    Above needs to be repeated 10 times before progression to other tasks.

    2. Normal operations

    All onboard personelle needs to participate in this exercise. Plane needs to have over-capacity to take-off under one engine. various take-off position training with various load weight. But take-off is not allowed under no wind from the first two take-off positions. At 25 knots headwind TOW at position 1,2 is limited to under 28100kg. (Russia navy limits at 28000kg). From 3rd take-off position at 0 knots headwind TOW also limits to below 28000kg. With 25 knots headwind there is no weight limit from position 3.

    3. Emergency take-off from position 3 (I suspect this is to rapidly respond to serious air threats)

    Only used under wartime situation, when training need approval from flight bridge officer (<-any idea the proper title?). Sill operates under single engine take-off overcapcity assumptions, but relaxes the take-off profile to allow for dip in altitude. Taking off from position 1,2 under 0 knots headwind, TOW is limited to 22700kg, 25 knots, under 30000kg.


    ==end==
     
  4. Jeff Head
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    Jeff Head Super Moderator
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    Is the intent to compare to the J-15 and show what it can potentially do?

    If so, it should be in the J-15 thread.

    If the intent is purely for the SU-33 itself, then it should be in a separate SU-33 thread under the World Military Forum...which this could simply be move there and become.

    But if it is to reference the J-15 and its capabilities it should be in the J-15 thread.

    Otherwise, it is not a Chinese military/Navy/Air Force thread and really belongs in the World Military Forum.
     
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  5. Bltizo
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    Bltizo Senior Member

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    It's meant to exist so that people can easily do an internet search for this information, which is partly relevant to J-15, partly relevant to STOBAR carriers in general.

    If it's in the J-15 thread it'll eventually become lost among the vastness of the many posts in that thread.

    This way, by being alone it will be able to be easily found by anyone who does a search of "Su-33/J-15 ski jump reference" -- the above posts aren't really meant to stimulate discussion, but to be a source in and of itself.

    It may be useful to even lock this thread so that it can be more easily referenced in future.

    (the sub-category in which this thread is located isn't that important, but I felt navy is the most relevant)
     
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  6. Jeff Head
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    Jeff Head Super Moderator
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    Well, since you want it relevant to STOBAT carrier in general, and as an example, I will put it in World MIlitaryt, and reference as such and make it sticky...that way people can still talk about it.

    I believe it will be a good thread...just want it in the right place.
     
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  7. Bltizo
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    Bltizo Senior Member

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    Okay, sure that's fine.

    More important for me is having the posts and information accessible on the forum in a prominent way, instead of in the middle of a thread that is hard to find.
     
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  8. Jeff Head
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    Jeff Head Super Moderator
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    Oaky...got 'er done.

    She is now a sticky reference thread in the World Military Forum.

    "STOBAR aircraft Ski-jump performance (SU-33/J-15)"
     
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  9. FORBIN
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    FORBIN Senior Member

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    Completely not agree, i don' t know where you catch these files... and all experts say ONLY CATOBAR aircrafts carriers allow fighters to get a full weapons load, you can see video the speed, much more low with CATOBAR no doubt and Jeff have confirmed many times and i have also see sailors confirmed again it during interview.

    An Su-33 or J-15 is limited to about half payload or eventualy less fuel.

    Expert for naval matters...
     
    #9 FORBIN, Sep 3, 2016
    Last edited: Sep 3, 2016
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  10. FORBIN
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    FORBIN Senior Member

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    Ask to Popeye ...
     
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