Too complicated and dangerous for regular use.
Furthermore, J-15 should already be able to take off from the ski jump with full load with high head wind in the first place.
PLAN Aircraft Carrier programme...(Closed)
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Too complicated and dangerous for regular use.
Furthermore, J-15 should already be able to take off from the ski jump with full load with high head wind in the first place.
Do you know if there is any evidence on that? I just find it to be very convenient. a 27 tonne bird, with a pair of 135 kN afterburning turbines (89 kN bench) so aiming for 80 mph for take off speed (i have no idea, but 80 seem like the magic number for a ski)
Using simiple newtonian kienamatics...
Vf^2 = Vi^2 + 2*a*s
s = around 100m long?
F=m*a; therefore a = 2*135*1000/27000 = 10 m/s^2
therefore Vf = 44.7 m/s = 90 mph
So yes, it seems possible... But 135 kn is a bench number; (which also an at altitude number); therefore, considering exhaust gas punch through and losses, low altitude performance of engines, like wheels contact, inlet power reductions.... this seems that take off is very tight if possible.
Well, it should be convenient because that is what the soviets designed it for (lol)
I've already reposted supporting material for this over and over again, it has become a bit of a chore.
But I've got a few extras to add now I suppose.
First is this famous series of charts from a chinese military magazine. The context and the magazine has never been made fully clear, but the sheer detail to which they list the various take off, range and headwind profiles makes me think it is not some numbers that have been just made up
http://www.sinodefenceforum.com/nav...-programme-news-views-44-6479.html#post247737
Second, is the book,
Gordon, Yefim (2001). Flankers, The New Generation. Midland Publishing. p. 91. ISBN 1 85780 121 0.
In it, the author supposedly states "Even using the station which afforded shortest take-off run of only 105m, Su-33 can take off easily with full fuel and weapons load."
I don't have the book, but the fellow is a fairly well respected Russian military aviation watcher, and his statement corresponds with positions held by other Russian watchers.
Third, is a book specifically about the Su-33 buy Andrei Fomin, and a relevant section is translated below:
""Su-27K with incomplete filling of fuel tanks, depending on the amount of suspended missiles " air" , ranged from 25 to 28 tons while he was starting thrust 0.9-1.0 and could take off from the 1st or 2nd starting position on the deck of the ship ( the takeoff distance of 105 m ) . With full fuel tanks and maximum ammunition missiles " air" take-off weight increased to 32 tons, and thrust was reduced to 0.8. In this case vzleet aircraft had to be made with the third starting position ( takeoff distance of 195 m ) . Hence , the aircraft could start and the maximum load it with bombs and rockets .
Despite a significant increase in landing weight , compared with the Su -27 , the introduction of a new wing mechanization and canards possible to reduce the approach speed shipborne fighter up to 240 km / h (Su- 27, usually landing with a speed of 270 km / h and only it absorbs the leveling process to 225-240 km / h , depending on the weight of the seat ) . In this case the mean free path of the Su- 27K on the deck when braking its arresting gear was to be only 90 m""
These stats correspond with the take off performance of Su-33 taking off from a carrier at zero headwind in the magazine scans I posted
Fourth, if anyone bothers goes around to a Russian military aviation forum of their choice and ask this question, you will get a host of the same answers that the Su-33 can (and even did) take off from ski jumps with full loads.
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And in your calculation, things like aerodynamics and also the all important headwind must be taken into account as well.
asif iqbal
Lieutenant General
Just check back in this thread
From launch one position J15 can take off with full load and fuel while into a head wind which is always going to be the case until the carrier is stationary which is highly unlikely, running at 30 knots plenty of head wind
From launch 2 position J15 can take off without head wind full load
There is a problem with your calculation. The J-15's will be using the AL-31 meaning the engines each only have 125 kN with afterburn.
plawolf
Lieutenant General
The limitation on the J15 launch weight is determined largely by the maximum speed its landing gear is rated to hit the ski ramp.
To fast and there is a good chance your front gear will give way on you and give you a very bad day. This is why ski jumps and cats don't mix.
Sticking a rocket on the back of a J15 might give it a good kick, but you won't be able to use the ski jump and instead would have to launch off the angled deck. That in turn means you need a bigass rocket to give the J15 enough acceleration to launch from the angled deck with a full load.
Possible, but expensive since the rockets would be single use, and would likely require strengthing of airframe to use, and may even have to take up one or two hardpoints.
It just all gets very complicated and unnecessary when the PLAN can just loft a strike package of J15s fully loaded with ordinance and buddy refuel them.
To fast and there is a good chance your front gear will give way on you and give you a very bad day. This is why ski jumps and cats don't mix.
Sticking a rocket on the back of a J15 might give it a good kick, but you won't be able to use the ski jump and instead would have to launch off the angled deck. That in turn means you need a bigass rocket to give the J15 enough acceleration to launch from the angled deck with a full load.
Possible, but expensive since the rockets would be single use, and would likely require strengthing of airframe to use, and may even have to take up one or two hardpoints.
It just all gets very complicated and unnecessary when the PLAN can just loft a strike package of J15s fully loaded with ordinance and buddy refuel them.
Thanks for the scans, I have some doubts, but they are publication.
Do anyone know what is the thrust developed at sea level in an air frame?
The reason why I ask about an assist rocket is that, I keep thinking of midway: when Hiryu spoted the Yorktown, she had to launch immediately her strike packages - which sounds kind of stupid if her fighters have to loiter around, buddy refuel before going on the strike (also missing a strike aircraft as well, being used up as a refueler).
A small rocket the size of the drag chute on the su-27 should be able to develop around 20 kN trust for around 10 seconds? I would think you can still use the ski. Which.. also solid booster rockets are high thrust low specific impulse ideal for low altitude work... which exhaust is quite toxic... so I am just throwing things around.
Of course Catapults solves the dilemma but, the fact is, liaoning doesn't have them.
Not practical on a CV. You may have to clear the deck. And with that ski ramp room is at a premium. Rockets not in a pod/launcher are not the safest ..
You'd need a magazine below decks just to store those rockets. They do take up space. That magazine would take up storage for other air launched weapons.
The US called then JATO bottles.
JATO = Jet Assisted Take Off.
Not sure if the Blue Angels C-130, Fat Albert, does the JATO launch. Here's a video of a JATO launch.
[video=youtube;eRM1Ng1kmlk]http://www.youtube.com/watch?v=eRM1Ng1kmlk[/video]
It's just not practical aboard a ship.
You'd need a magazine below decks just to store those rockets. They do take up space. That magazine would take up storage for other air launched weapons.
The US called then JATO bottles.
JATO = Jet Assisted Take Off.
Not sure if the Blue Angels C-130, Fat Albert, does the JATO launch. Here's a video of a JATO launch.
[video=youtube;eRM1Ng1kmlk]http://www.youtube.com/watch?v=eRM1Ng1kmlk[/video]
It's just not practical aboard a ship.
Like I said, there's not only the scans, but also books as well, written by people who know much more about the development of the fighters than almost anyone else outside of the industry.
TerraN_EmpirE
Tyrant King
plus there is the issue of safety. [video=youtube_share;cHUsGFGhfmk]http://youtu.be/cHUsGFGhfmk[/video]
check the ramp on this one.
check the ramp on this one.
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