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Sukhoi Su-30 MKI - Purpose of Thrust Vectoring

Hub question: What is the purpose of Thrust Vectoring Nozzle in Sukhoi SU-30 MKI? I read this on some site and interested in more details.

Hi friend. This is a really nice question for me to answer. The answer was too difficult so it took me 3 days to research to come to the whole conclusion. There are various websites on the net which have information related to the same and below is my input after going through the information available. I also contacted various students who are studying aeronautical engineering and pursuing a career in the same and I gathered the details from them also. Below are some of the most common questions about thrust vectoring control system.

What is thrust vectoring?

Thurst vectoring is one of the best features in Sukhoi SU-30 MKI. The nozzle works such that we can direct the engine thrust in a desired direction, which enhances the maneuverability of the aircraft, and it is this reason due to which Su-30 MKI is able to perform cobra-type maneuvers required during dogfight. India is the second country after Russia to have an aircraft in service with such great thrust vectoring capability.

USA has TVC in F-22 , X-31 , AV-8B Harrier II

UK has EF 2000

Germany has EF 2000

The maximum tilt angle for the SU-30 is 32 degrees in horizontal and 15 degrees in vertical. Even Eurofighter Typhoon does not have thrust vectoring. There are two types of thrust vectoring systems, 2D and 3D. Read below for more details on them:

A Book on Thurst Vectoring Research and History

What is 2-D and 3-D thrust vectoring and what is the difference between them?

2D means directing the thrust in horizontal and vertical directions whereas 3D means directing the thrust in vertical, horizontal, and angular directions. In 2D, nozzles can be deflected in only one direction (either both vertical or horizontal) and in the case of 3D, there has not been any correct information because a few days back I read an article which stated that 3D can be deflected in different planes and yesterday I read another article and it stated that nozzle of 3D can be deflected in the opposite direction. So there is quite confusion about the working of 3D nozzle.

The most important aspect related to any moving machine or vehicle or airplane, etc. is the propulsion power and the type of propulsion, etc.

Aspects related to propulsion, etc. could be best studied when they are related to an airplane, especially due to the fact that there is ideally zero friction between the airplane and air/unlike the case in cars, bikes, ships, etc.

The concept of three-dimensional vectoring can also be applied to a propeller-based aircraft. The principles and the benefits will be good if not dramatic when compared to the jet, rocket power, etc. The earlier types of jet technology were purely axisymmetric and the thrust was on the lines of the axis of the jet engine.

The two-dimensional thrust vector allows the propulsion to be deflected in two directions, up and down, or sideways, left or right.

Three-dimensional thrust vectoring allows the propulsion to be deflected in all four directions, i.e., up and down and left and right. It is even possible to add roll control using differential ideology. Basically, the propulsion of one jet is directed upwards while the other is directed downwards.

The three dimensional thrust vectors allow the aircraft to perform all types of complex maneuvers. One can very well say that three-dimensional thrust adds four more controls to the aircraft. In the absence of 3-dimensional thrust, the pilot has to depend heavily on the basic controls such as rudder, elevator, flap, airelon, etc. It is quite possible that some complex maneuvers can be carried out without using the basic controls at all. The response time is improved a lot by using such multidimensional thrusts.

Su30 MKI while take off illuminating Thrust vectoring nozzles in Aero India Show in 2011

Su30 MKI while take off illuminating Thrust vectoring nozzles in Aero India Show in 2011

Now learn how the thrust-vectoring nozzle is controlled?

Presumably, the nozzle sense is controlled by the avionics inside it, right? But it is the pilot who is given a direct feed on the nozzle angle? Because maneuvers like the Pugachev's Cobra super maneuvers are too complex to fathom.

Pugachev's Cobra or dynamic braking is a maneuver in which within 3 to 4 seconds, the nose of the aircraft is pulled up to high angles of attack (80--110 degrees) and then returned to normal horizontal flight. This causes intensive loss of airspeed. You can execute this maneuver from level flight at various altitudes and at indicated air speeds of 350--450 kilometers per hour.

In level flight at the appropriate entry speed of 350 to 450 km/h, disable the AOA limiter. Execute the cobra by pulling the stick fully aft. As the nose reaches the vertical (pointed straight up), allow the stick to go to neutral and let the nose fall back down to level flight. Smoothly increase thrust toward the end of the maneuver. The AOA limiter will automatically re-engage after executing the cobra.

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Two facts that make thrust vectoring difficult for other planes

  1. The main difficulty is to design a nozzle bearing that can work smoothly at extremely high engine exhaust temperatures, basically a problem of finding the right material. The Russians are using some alloy for this and some advanced lubricant they invented.
  2. The second is a problem of flight control. Thrust vectoring changes the complete control law for your aircraft. As a simple example, one of the very difficult fields in aerospace is tethered vehicle flight dynamics because it involves an asymmetric thrust vector. Thrust vectoring is having that vector in your control law. This is the reason that Americans are behind the Russians and they want to integrate the TV into the flight computer, so that the pilot can still fly with a single joystick; however, the Russians who are more practical and generally just want results, have a separate control for controlling TV of the nozzle, and the pilot uses his own feel of the aircraft to fly and uses the thrust vectoring appropriately.

India has manufactured AL-31 engines with thrust vectoring nozzles under license at the Nasik Plant (Hindustan Aeronautics Limited).

Which other aircraft are using this facility?

  • Harrier 1 and 2.
  • Yakovlev Yak-141 which is the first supersonic VTOL fighter (Vertical Take-Off and Landing).
  • JSF which is a naval version still has some problems with the vertical take-off and landing thing out there, so the US engineers had to call on the Russian engineers from Yakovlev to help them fix this problem.
  • V-22 Osprey with VTOL and STOL (short takeoff and landing).

If anyone thinks that helicopters are using thrust vectoring, then I am too sorry because they do not come under the category of fixed-wing aircraft, as they are rotary wing aircraft. All VTOL fixed-wing fighters though have thrust vectoring, they are not using it to achieve higher maneuverability. They simply use to bypass the engine exhaust through another duct pointing downwards. The challenge there is to achieve stability because for thrust pointing directly downwards, there are a lot of stability issues that pop up, not to mention conditions when there is high wind or gusts in the atmosphere which is very common on a ship in the ocean, but the main challenge as I pointed earlier in fighters when they use thrust vectoring for maneuverability is that then you have to move the nozzles itself and not just bypass the exhaust through a separate duct, so designing the bearing becomes a difficult issue.

I will come up with more advanced answers related to thrust vectoring nozzle and maneuvers that are possible by using this system in my upcoming hubs.

Take care. Happy flying...........

P.S.: As I promised, I have created a new hub which is the second part of this hub - Thrust vectoring Sukhoi Su-30 MKI Part II

In this new article, I have written on thrust vectoring success by American's on V-22 Osprey and compared it with Sukhoi SU 30 MKi. I hope you will enjoy this information.

Sukhoi su Flanker at Indian Service

Sukhoi su Flanker at Indian Service

Thrust vectoring control system - fine graphics

Thrust vectoring control system - fine graphics

Sukhoi SU 30 MKI toy showing thrust vectoring nozzles.

Sukhoi SU 30 MKI toy showing thrust vectoring nozzles.

Pugachev's maneuver performed using thrust vectoring system.

Pugachev's maneuver performed using thrust vectoring system.

Sukhoi Su-30 MKI thrust vectoring control rear view

Sukhoi Su-30 MKI thrust vectoring control rear view

F-22 Raptor in air

F-22 Raptor in air

X-31 aircraft mid air.

X-31 aircraft mid air.

AV-8B Harrier II is a second generation vertical takeoff and landing VTOL and short takeoff and landing STOL ground attack fighter aircraft

AV-8B Harrier II is a second generation vertical takeoff and landing VTOL and short takeoff and landing STOL ground attack fighter aircraft

Comments

Neil on October 05, 2012:

Vishal,

I never said I am against upgrading of MiG 29s. But I disagree with adding tvc engines on the MiG 29s. I have answered your questions/statements below:

1. Fitting Mig-29s with THrust vectored engines is still a good idea i feel.

Neil: For your information, we are already upgrading our MiG 29s to SMT standard. Adding TVC engines on our MiG 29s would not make sense. The upgrade of all IAF MiG-29 "Baaz" to latest MiG-29UPG standard is in process, which will include latest avionics, Zhuk-ME Radar, RD-33 series 3 engine, weapon control systems etc., enhancing multirole capabilities by many-fold. Also, you will have to write new control laws for the TVC controls which does not make sense. The ugrade costs would go so high, it would almost be the same as purchasing a new aircraft.

2. We have just spent a lot on updating 3rd generation Mig-27. Why is it so then..?

Neil: We should have started the upgrades long back, before the MiG 27s started dropping like flies. If you remember during the Kargil war, One MiG 27 crashed due to a faulty engine. This is NOT acceptable in a war. The escorting MiG 21 went to look for the MiG 27 and was also shot down by a shoulder mounted stinger missile.

Russia and Ukraine have retired their MiG 27s already. We have not because we don't have a choice as there was (and is) a huge delay in MMRCA procurement.

3. Only beause we have just purchased these aircraft? only 18 years back.

Neil: What are you talking about? We inducted MiG 27s in 1986 and MiG 29s in 1985. Please get your facts right.

4. We are also spending a huge amount of money on upgrading Mirage-2000H working with Dassault. According to you all these things must be useless then. Because we purchased Mig-29 and Mirage-2000H at the same time if you know. I know Mig-29 has RD-33. I also read dear.

Neil: Maybe you read but I am not sure if you pay attention to facts and practicality and in some cases I am astonished by your misinformation. Obviously we need to upgrade aging aircrafts as every other country does. But if you think upgrading an aircraft is be all and end all of everything, then you need to think again. Upgrading an older aircraft increases the service life and enhances the capability of the original aircraft to a certain extent. Thats all. There is a limit to the extent an existing aircraft can be upgraded after which, financial feasability and lifecycle cost comes into question.

5. Ohh my god...we can rule Asia Pacific Region.

Neil: Sorry to rain on your parade but you need a reality check. Before ruling asia, don't forget the dragon called China.

6. 200 FGFA

Neil: Looooooooooooonggggg way of. First the PAK-FA has to be ready. THEN the FGFA will be worked upon. In case you haven't heard the latest, PAK FA has been delayed by 2 years.

7. 60+ Upgraded Mig-29Bs (to Mig-29M3)

Neil: Wrong again! The upgrade standard will be MiG 29UPG which is similar to SMT standards but with an international avionics suite.

8. We may also go for some U.S. made fighter aircraft.

Neil: Why do you think we never went for F-18 Super Hornet or F-16 Block 60? US never agreed to Total Transfer of Technology. Their deals always come with strings attached and prone to sanctions.

9. May be 40 F-35L-2 in the very recent future.

Neil: Now I am 100% sure you are out of mind. Its an incredibly costly fighter with extremely limited capabilities and high maintenance. It can carry only two A to A missiles in its internal bays and is more of a strike fighter with limited air to air capabilities. It has a low thrust to weight ratio meaning it can't maintain a sustained turn rate which is crucial for a dog fight at high AOA with a top speed of only Mach 1.6.

10. Immediate compensation is required for this in the form of some quick purchase of some 20 new combat aircraft to fill the gap created by Mig-25's retirement. We are GARUDLESS since 7 years.

Neil: Do you even know why the MiG 25s were retired? It was simply because we don't need them anymore. Its an incredibly high maintainance aircraft with no upgrade programs. Its role of recon can now be carried out by spy satelites. It sis technologically obsolete.

We do not need any aircraft to replce the MiG 25s which in anycase were just a handful.

Suggestion as one aviation fan to another: Get real, be practical and always keep yourself updated and remember that no aircraft in this world is invulnerable. If there are measures, there are counter measures.

Good day to you!

Vishal Bulbule on February 18, 2012:

To Neil

You r right dear. V-22 is only an example of thrust vectoring. Not thrust vectored engine. Fitting Mig-29s with THrust vectored engines is still a good idea i feel. We have just spent a lot on updating 3rd generation Mig-27. Why is it so then..? Only beause we have just purchased these aircraft? only 18 years back. We are also spending a huge amount of money on upgrading Mirage-2000H working with Dassault. According to you all these things must be useless then. Because we purchased Mig-29 and Mirage-2000H at the same time if you know. I know Mig-29 has RD-33. I also read dear.

Ok lets just enjoy Rafale's selection. I am so happy to see this aircraft got selected. It was always my favourite.

126 (200..?) Rafale

270+ Sukhoi 30 MKIs,

200 FGFA

50+ Upgraded Mirage-2kH

60+ Upgraded Mig-29Bs (to Mig-29M3)

Ohh my god...we can rule Asia Pacific Region.

We may also go for some U.S. made fighter aircraft.

May be 40 F-35L-2 in the very recent future.

We have already started operating Russian Mig-29 K which is considered a very good naval jet.

But we have taken 5 extra years in selecting MMRCA. That was an idiot act. Immediate compensation is required for this in the form of some quick purchase of some 20 new combat aircraft to fill the gap created by Mig-25's retirement. We are GARUDLESS since 7 years.