Potential PLANAF Carrier Aviation Alternatives
- Thread starter crobato
- Start date
i know that the russians/soviets like to use ski jump for take off. why don't they just captlulats like the americans for mig29s and su33
Pointblank
Senior Member
The Project 1143.7 Orel Ul'yanovsk class was slated to use catapults, and she was slated to have a airwing of 27 Su-33's (or 27 MiG-29K's), 10 Su-39's, Yak-44's, and 15-20 Ka-27 Helix A's, for a total of 70 aircraft. She was scraped at 40% complete due the fall of the Soviet Union and the resulting economic conditions that followed. Using the STOBAR configuration is cheaper and easier to implement than using the CATOBAR configuration as found on the USN's carriers.
Becouse the orginal decision to fit Kuznetsov and her sisters with catabults failed due political decision to boost up the V/STOL development. It was then discovered that the newest jets, MiG-29K and Su-27 were actually powerfull enough to take off from the ski-jump as well, so (and with pressure form Sukhoi) there really was no need for it in the short timeframe. With Uljanovsk the catabults were added as the Yak-44 was unable to take-off from the Ski-jump...but all these came naturally to end when Soviet union broke down. I'm certain that ultimately, perhaps in the follow-on to Ulyanovsk, Soviets would have turned totally to CATOBAR as it's benefits are so big over STOBAR...
ok so the russians has invested in caplulats. But how can a big plane like the su33 take off from a runway that is less than 600 ft long with out any assitance? I.E caplulats. I know it uses the "ski JUMp" technqiue and also the weapons load and fuel load has been reduced, but still the thing gotta weight around 25-27ish tonnes. and a normal SU33 using a regular runway to take off which is about 4000-6000ft long. SO my questions how does a heavy plane like taht take off at such short distance
The point is not so much the minimum speed that is required to generate enough lift, but for the take-off roll.
When taking off over the sky-jump, the plane is given a higher angle of attack (AOA). That means the nose points in an upwards direction, and so does the airfoil (wing). This AOA makes the wing generate more lift than with 0° AOA at the same speed. And obviously, that's enough for a Su-33 to take off from a Kuznetsov.
Now if you want to roll (get the nose up) from a flat runway, you have to use the elevators (pitch them up to create a downward force at the aft of the plane). And to do that needs a higher speed/longer runway than is available on a carrier.
The use of canards or TVC also helps shorten the runway, since you can roll at lower speeds.
When taking off over the sky-jump, the plane is given a higher angle of attack (AOA). That means the nose points in an upwards direction, and so does the airfoil (wing). This AOA makes the wing generate more lift than with 0° AOA at the same speed. And obviously, that's enough for a Su-33 to take off from a Kuznetsov.
Now if you want to roll (get the nose up) from a flat runway, you have to use the elevators (pitch them up to create a downward force at the aft of the plane). And to do that needs a higher speed/longer runway than is available on a carrier.
The use of canards or TVC also helps shorten the runway, since you can roll at lower speeds.
To clatify, a Ski jump launch gets the aircraft off the deck BEFORE it has reached takeoff speed! When the plane leaves the deck it is on a ballistic trajectory (like a car that has gone over a hump backed bridge too fast) and while the wings are generating some lift, this is insufficient for the aircraft to 'fly'. The wings at this point only stabilise the direction/attitude of the aircraft and all things being equal the plane would then reach apogee (top of the arc) then drop back down into the sea. What actually happens is the aircraft is subject to further acceleration from its engines and reaches flying speed before it reaches apogee, and thus continues flying. If there is a problem (eg engine failure) then the upwards trajectory of the aircraft gives the pilot a few more seconds to eject than with a catapult launch before the plane hits the sea.
Those videos illustrate what I said exactly! When the jets leave the ski jump it is practically sitting on it's engine thrust for the first ten to twenty seconds. If you look closely you'll see that despite the high angle of attack the aircraft are moving mostly forwards rather than climbing upwards as it accelerates to flying speed, at which point it will start climbing away. The info I have on the ski jump launch comes from articles by and about the man who invented it, Lt Cmdr Doug Taylor RN.
BLUEJACKET
Banned Idiot
Yes, I saw it too but only for 1-2 seconds. If they were to start their takeoff from farther aft, if that was possible by the ship's architecture, would that produce higher speed to carry more ordinance? If so, a redesign of the flight deck should be given a thought by the Chinese, IMO.
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