J-15 carrier-borne fighter thread

[Blitzo]

As much as I respect the opinions of individuals who've served in the military and especially in this case given the relevance of previous naval positions and the topic we're discussing.... this is more of a question for physicists and engineers to study and simulate, and I'm doubtful as to just how useful service experience even aboard a CVN is for the question of ski jumps. I'd absolutely be interested to how Kwaig formed his opinion though, especially if his previous experience is informing his opinion.

Don't get me wrong, I'm sure a ski jump absolutely confers some deficits to the kind of planes that can be launched from it relative to a catapult, but I'm just wondering why the line is so specifically drawn at fighters with heavy loads. I think it would be fairer to say that certain aircraft with particular aerodynamic configurations, thrust/weight ratios, would be unable to launch... and that maybe certain weights would be less reliably launched or launched with a different take off profile compared with a catapult. But what these tidbits are is something that should be investigated and shouldn't be effortlessly tossed out with too much confidence.

 

[plawolf]

Couldn't a Kutz class type carrier could always wait till a slight storm or stronger gust of wind at sea is coming and take advantage of it to provide more lift for launching air crafts if head wind is the case?

They could, but such things cannot really be planned for or relied upon.

Having planes armed and fuelled waiting on a good and sustained gust of wind to launch is just asking for trouble, and brings up memories of midway, where by luck the Americans attacked as the Japanese were re-arming and re-fueling the bulk of their air wing, and so all but annihilated the entire Japanese task force.

 

[Engineer]

As much as I respect the opinions of individuals who've served in the military and especially in this case given the relevance of previous naval positions and the topic we're discussing.... this is more of a question for physicists and engineers to study and simulate, and I'm doubtful as to just how useful service experience even aboard a CVN is for the question of ski jumps.

Exactly. It is called appealing to authority. It's like someone who has only eaten chocolate cakes their whole life telling you how bad other flavours are, while proclaiming to be the authority on all cakes.

The Soviets had conducted tests with Su-33s when the Kuznetsov was still new. The findings were compiled into charts and figures and made their ways to this forum on multiple occasions. Naysayers just like to pretend such evidence does not exist. Yet those very same people have provided nothing whatsoever to prove so-and-so takeoff weight is not achievable with ski-jump. We can conclude that there are more evidences saying it is achievable than there are saying it cannot.

Even if there is a photo tomorrow showing J-15 carrying a full load of external weapons on the Liaoning, people will still find excuses to dismiss the evidence. Recall the situation with J-20: "It is photo shopped", "it is a wooden mockup", "it is a wooden mockup with engines", "it is a scaled RC plane", "it is a tech demonstrator with no weapon bay", "it is a tech demonstrator, interceptor, striker, anything but a forth generation fighter prototype", "oh, sure Chinese have new hardware but they haven't kept up with software *wave hands in air*, so it isn't an operational aircraft"...

 

[kwaigonegin]

As much as I respect the opinions of individuals who've served in the military and especially in this case given the relevance of previous naval positions and the topic we're discussing.... this is more of a question for physicists and engineers to study and simulate, and I'm doubtful as to just how useful service experience even aboard a CVN is for the question of ski jumps. I'd absolutely be interested to how Kwaig formed his opinion though, especially if his previous experience is informing his opinion.

Don't get me wrong, I'm sure a ski jump absolutely confers some deficits to the kind of planes that can be launched from it relative to a catapult, but I'm just wondering why the line is so specifically drawn at fighters with heavy loads. I think it would be fairer to say that certain aircraft with particular aerodynamic configurations, thrust/weight ratios, would be unable to launch... and that maybe certain weights would be less reliably launched or launched with a different take off profile compared with a catapult. But what these tidbits are is something that should be investigated and shouldn't be effortlessly tossed out with too much confidence.

Well if it makes you feel any better i also went to engineering school .. Also you are absolutely right in stating that different aircraft has different characteristics including the specifications for take off etc from the manufacturer itself which was why I specifically mentioned flankers since that really is what we're talking about here.

In many ways the lack of cats actually makes the argument even stronger because you dial or configure the launch based on the aircraft type. In the case of ski ramp you don't have that luxury since a ski ramp is nothing more than a platform to force high AoA for launch.

Forget about airplanes... Even a car driven over the skip ramp will go further than one driving straight into the drink because of higher launch angle however the difference is in the case of the car the lift is insignificant since the 'airfoil' is not made for flight.

Short of knowing the exact specifications of the su33s etc in terms of airspeed over airfoil, wing lift capacity etc we cannot say with 100% certainty that it can or cannot launch with MTOW however based on my own experience as well as the fact we have never seen any publicly available information of such I can conclude with relative confidence the flanker cannot launch off the ski ramp from the KUDZ under normal conditions.

 

[kwaigonegin]

I

They could, but such things cannot really be planned for or relied upon.

Having planes armed and fuelled waiting on a good and sustained gust of wind to launch is just asking for trouble, and brings up memories of midway, where by luck the Americans attacked as the Japanese were re-arming and re-fueling the bulk of their air wing, and so all but annihilated the entire Japanese task force.

I want to add also that you are also more at the mercy of nature when using ski ramp than you would cat.

 

[kwaigonegin]

Exactly. It is called appealing to authority. It's like someone who has only eaten chocolate cake their whole life telling you how bad other flavours are, while proclaiming to be the authority on cakes.

The Soviets had conducted tests with Su-33s when the Kuznetsov was still new. The findings were compiled into charts and figures and made their ways to this forum on multiple occasions. Naysayers just like to pretend such evidence does not exist. Yet those very same people have provided nothing whatsoever to prove so-and-so takeoff weight is not achievable with ski-jump. We can conclude that there are more evidences saying it can be done than there are saying it cannot.

Even if there is a photo tomorrow showing J-15 carrying a full load of external weapons on the Liaoning, people will still find excuses to dismiss the evidence. Recall the situation with J-20: "It is photo shopped", " it is a wooden mockup", "it is a wooden mockup with engines", " it is a scaled RC plane", "it is a tech demonstrator with no weapon bay", "it is a tech demonstrator, interceptor, striker, anything but a forth generation fighter prototype", "oh, sure Chinese have new hardware but they haven't kept up with software *wave hands in air*, so it isn't an operational aircraft"...

A link to those charts and figures would be nice. Also are we talking control environment or real world application?

would you say the kunetzov can launch her flankers at maximum weight all of the time, most of the time, rare oacasions or only when she is brand spanking new under near perfect sea state and optimum headwind and a brand new just broken in bird driven by a chief test pilot ?

 

[latenlazy]

Yano guys, it could just be that launching with MTOW from a ski ramp is impractical, and thus operationally untenable.

 

[Engineer]

A link to those charts and figures would be nice. Also are we talking control environment or real world application?

Link. I don't know Russian and can't find the Russian version.

would you say the kunetzov can launch her flankers at maximum weight all of the time, most of the time, rare oacasions or only when she is brand spanking new under near perfect sea state and optimum headwind and a brand new just broken in bird driven by a chief test pilot ?

Obviously, when Soviets did their tests, Kuznetsov was new and so was everything else. And of course, launch weight depends on the weather conditions at the time, as well as the launch position.

 

[delft]

In many ways the lack of cats actually makes the argument even stronger because you dial or configure the launch based on the aircraft type. In the case of ski ramp you don't have that luxury since a ski ramp is nothing more than a platform to force high AoA for launch.

No Kwaig, it is the way to launch aircraft at a low AoA and so with a low induced drag. It enables you to launch at a low speed compared with using a cat because the aircraft doesn't need flying speed when it leaves the ramp as it can accelerate further in the air. It needs adequate control of course.

 

[Blitzo]

Well if it makes you feel any better i also went to engineering school .. Also you are absolutely right in stating that different aircraft has different characteristics including the specifications for take off etc from the manufacturer itself which was why I specifically mentioned flankers since that really is what we're talking about here.

In many ways the lack of cats actually makes the argument even stronger because you dial or configure the launch based on the aircraft type. In the case of ski ramp you don't have that luxury since a ski ramp is nothing more than a platform to force high AoA for launch.

Forget about airplanes... Even a car driven over the skip ramp will go further than one driving straight into the drink because of higher launch angle however the difference is in the case of the car the lift is insignificant since the 'airfoil' is not made for flight.

Short of knowing the exact specifications of the su33s etc in terms of airspeed over airfoil, wing lift capacity etc we cannot say with 100% certainty that it can or cannot launch with MTOW however based on my own experience as well as the fact we have never seen any publicly available information of such I can conclude with relative confidence the flanker cannot launch off the ski ramp from the KUDZ under normal conditions.

I appreciate the reply.

Basically, in your last paragraph, you agree that we cannot say for certain whether Su-33 can or cannot launch from a kuznetsov class ski jump at MTOW -- and you're deferring to the lack of photos and videos to reach your conclusion.

But as has been discussed to great length over the last page or so, the lack of photos can easily be attributed to the fact that the world's single STOBAR carrier of the past few decades was barely kept alive in an operable state let alone well funded and equipped enough with the munitions to launch their fighters with the loads we're talking about. Not to mention there was even a need for Su-33s to launch with large loads given Kuznetsov was basically kept on life support just to retain the Russian Navy's limited carrier expertise.

In other words, the lack of evidence we have is only able to prove that the Russian Navy is/was unable to launch heavily loaded fighters from their ski jump carrier, not that this particular thing is impossible for all ski jump carriers and heavily loaded fighters ever.
Which is why I eagerly hope for more pictures and videos of Liaoning and Vikramditya in operation to hopefully shed more light on this matter, given they are going to be much better funded and equipped than Kuznetsov was for the last few decades. But unfortunately it'll probably take a few years for them to reach a stage where we can get the few photos or seconds of video we need.

Until that time, I'll reiterate that it makes most sense to say that the jury is still out. We dont' have the modelling and simulation and numbers to do anything near an accurate estimate of what we want, and the lack of evidence we have is (for lack of a better description) acquired from a navy who wasn't practicing truly operational fixed wing naval aviation

We can use the same logic of "lack of videos/photos" to say that production Su-33s cannot take off with any kind of munitions at all because the only evidence we have of it is the one video online of a T-10K prototype taking off from kuznetsov, and no photos since then. But obviously that's a ridiculous proposition and a fallacious one.