Round One JF17 - Poor Display By Tejas Took 10 more sec Than JF17 To Go Up

[cerberus]

Now Where Was I Yeah About Delta Wing

Question Was Is Delta configuration has some drag disadvantages compared to JF 17 kind of design, How Tejas will fare against JF17 in pure dogfight without missiles ?

The delta is a bit more nuanced than that. The drag coefficient for a delta wing only impedes flight at low speeds-low altitude flight profile, but does better than other wing types in high speed, high altitude, high maneuver flight profiles.

Once the plane catches speed, there is a change in how the fluid dynamics work in favor of the delta. Check this

The primary advantage of the delta wing is that, with a large enough angle of rearward sweep, the wing’s leading edge will not contact the shock wave boundary formed at the nose of the fuselage as the speed of the aircraft approaches and exceeds transonic to supersonic speed. The rearward sweep angle vastly lowers the airspeed normal to the leading edge of the wing, thereby allowing the aircraft to fly at high subsonic, transonic, or supersonic speed, while the over wing speed of the lifting air is kept to less than the speed of sound. Some other advantages of Delta wings are:-

• Rise in Transsonic drag is gradual and peak drag in supersonic flight is reduced

--Lift is spread over the broader chord
--Senstivity of Drag to Mach Number is redued greatly
--Satisfactory cross sectional area can be achieved very easily

• Change in lift component CL and lift curve slope CLα with the value of Mach Number M is gradual.
• A very high stall angle is achieved by increasing the angle of atack, as a flow energising vortex is generated by the leading edge of the wing at high angles of attack.
• It allows for light wings with high bending and torsional stiffness.

--More volume for fuel and gear is available in thicker wings.
--Fluttering and aileron reversal problems are wholly eliminated.

• Acceptable level of maneuverability and ease of handlingis achieved because of low wing loading.
• Wingspan is small and hence does not require folding.
• Available area for external storage is large enough.
• It is easy ,simple and relatively inexpensive to manufacture.
• The addition of canards to the aircraft increases the overall lift,hence enabling the aircraft to perform extreme maneuvers and at the same time improving the low speed handling and lowering the landing speed

Couple that with relaxed static stability and you have a plane that is probably the most suitable plane for emerging victorious in dog fights.

Delta design is the holy grail of supersonic air dominance, be it dogfights or missile launches. If the missiles themselves are hypersonic then the speed adds up. It's almost like dropping a space rod. That's why everyone is moving onto the delta design, Rafale, Typhoon, Tejas and US B2 spirit.Etc

TC
Cerberus

 

[Chanakyaa]

Thank you, that is EXACTLY what I have stated.


That is because it's theirs. The type and intensity of responses may vary but most will try to defend their state's achievement; much more so by those that have lesser knowledge. Hence the splattering of wikipedia links and everything they can find.

That is not to say that the platform is bad, but each platform has its strengths and weaknesses, and my dissappointment is not with the Tejas itself but really how the program management and primary customer has made its utmost effort to screw the gem of a platform and the human resource they have.

The Point is : THERE IS A REASON , why the 4.5 Gen Typhoon, Rafale , Mirages and Gripens , The Famous, Delta daggers And My fav Jet : Pure Interceptor, Avro Arrow , The Most Advanced Jet of 50s are/were ALL DELTA.
Period.

Now carry on, .. Mine is better than Yours.. !

 

[knight11]

Yah hence when I get some free time hehe. It's been a while since I have touched something at this fundamental kind of way, it may take time for me to unrust, but I do remember a lot of the fun I had back in the day some years back...and I don't think I have forgotten the basic and important stuff (I hope). I will probably start with some very basic modelling and then if the results are decent, I will use a better software package to refine it. Let's see! Stay tuned!

I will be looking forward to you when you would find time to do some CFD modelling for LCA Tejas, and Pls tag me. Can you give some inputs on the wing design of the LCA, specially speciality of the wings near the fuselarge, which is different in planar and the pocket arangement, a unique idea to pass the wind just above the wing, -- Does it removes the cannard sucessfully by doing its job.

Here is one guy who have done CFD modelling of LCA using the software called Flightstream.

The Beta Coefficient: A preliminary performance review of the Indian Light Combat Aircraft

 

[Great Sachin]

some shameless thread title....actual scenario is just opposite....JF17 took 10 sec more than LCA....
that to when JF17 chickened out

 

[Danish saleem]

Brother,

J

Actually Tejas is 6 seconds faster than Jf17.

Tejas Take off in 14 seconds in both Iron fist 2013 and Bahrain.

0:48 to 1:02 from Iron fist 2013

Now see JF17 take off in 20 seconds

~At Paris 0:0 to 0:20

~at Farnborough England 6:31 to 6:51

Brother,
JF-17 taking off vertically, which need more acceleration before taking off! check the normal take off of JF-17!

 

[danish_vij]

For non technical Fanboys here to understand what prominent posters @Oscar and @Nilgiri are in discussion here

Let me make simple matter for Fanboys

DELTA WING:
It is one of the most common wing planform that resembles a Triangle or Δ structure.

There are mainly 4 variations of Delta wing configuration.
1. Tail-less Delta (LCA)
2. Tailed Delta (Mig-21)
3. Compound Delta (LCA)
4. Cropped Delta (F-16)

Tailed-Delta has better handling where as Cropped-Delta has better AoA. Compound Delta is used to create high-lift vortex and reduce drag. Although use of canards and control surfaces like Dassault Rafale and EF Typhoon can provide other variations too.

At the beginning Delta wing is experimented on high speed supersonic aircraft to achieve more stability during supersonic flight. But this causes instability in subsonic speed i.e below MacH.Generally Pure Delta configuration is preferred for designing Aircraft with supersonic Interceptor role. But as generation advanced Interceptors are no more required and what we call as Multi-role or Swing-role fighter comes into view. So pure Delta configuration idea is dropped out instead Compound delta and Canard-delta is used now-a-days.

ADVANTAGES:
-The Delta wing reduces the shock wave produced during the transition from subsonic to supersonic mach thus reducing the drag at higher mach. So now aircraft doesn't have to sacrifice any internal energy to compensate for the air drag.
-The delta planform gives the largest total wing area (generating useful lift) for the wing shape, with very low wing per-unit loading, permitting high maneuverability in the airframe at higher mach.
-Also Delta wing aircrafts can carry more internal fuel and ammunition because they are more stronger than swept wing planform as their fuselage Centre of gravity is far in front.
-In delta wing, at higher AoA the leading edge of wing creates a vortex which gives a high stall angle.
-As the delta wing is simple, it can be made very robust, and relatively inexpensive to build as well as simple to manufacture. That's why we see so many aircraft with Delta wing configuration. Mig-21, Typhoon, Rafale, Tejas.

LIMITATION:
-The tail-less delta doesn't provide enough lift and sufficient stability at lower mach or subsonic speed which is very important in dogfight. But it can be compensated by providing a compound delta configuration. The best example is HAL Tejas, which is a tail-less delta but with compound delta configuration.
-In canard-delta i.e EF.Typhoon or D.Rafale as the mach number increases so as the centre of lift shifts. But this is a minor drawback which can be compensated with skilled pilot.
- In T-tail delta configuration it gives rise to deep stall condition as airflow over the wing is reduced


The Tejas is a tailless, compound delta planform. This planform is designed to keep the Tejas small and lightweight. The use of this planform also minimises the control surfaces needed (no tailplanes or fore planes, just a single vertical tailfin), permits carriage of a wider range of external stores, and confers better close-combat, high-speed, and high-alpha performance characteristics than conventional wing designs. Extensive wind tunnel testing on scale models and complex computational fluid dynamics analyses have optimised the aerodynamic configuration of the LCA, giving it minimum supersonic drag, a low wing-loading, and high rates of roll and pitch

@SpArK @Oscar +ve rating for this guy??

 

[kaykay]

Brother,

J


Brother,
JF-17 taking off vertically, which need more acceleration before taking off! check the normal take off of JF-17!

Without comparing both, I would like to raise few points for both aircrafts.
1. JF-17 took long for takeoff and go on vertical flight right away but couldn't sustained for more than 3-4 seconds.
2. Tejas took short takeoff, didn't go for vertical flight right away but when it did, it sustained it for much longer period of time.

 

[My-Analogous]

isnt it funny that LCA took just 12 seconds to be completely in air and JF17 takes well over 20 seconds 0:34 to 0:54 (at 34 the plane was already moving) to even get in air in paris. Tejas completed the run way to start show and should have been a rule from the organisers. Very bad observation.

Interesting to see how much time LCA need for vertical take off only then true comparison can be made.

 

[My-Analogous]

Without comparing both, I would like to raise few points for both aircrafts.
1. JF-17 took long for takeoff and go on vertical flight right away but couldn't sustained for more than 3-4 seconds.
2. Tejas took short takeoff, didn't go for vertical flight right away but when it did, it sustained it for much longer period of time.

There are various reasons, may be PAF don't want to show full potential of aircraft or Pilot just shift its priority after achieving the target. But we don't have any doubt that JF17 can do Vertical take off. About JF17 takeoff please check this video on 2010 clearly show JF takeoff in 10 sec.

 

[arp2041]

I think this is the RIGHT time for China, Pak, BD, Bhutan, Nepal, Maldives, SL to ATTACK India since TEJAS took 10seconds more to go UP!!!

 

[koolio]

To be honest "Junk"F - 17 is no match for Tejas Period

Good for you, I suppose the Tejas has been made with vedic composite materials, JF17 is a proven fighter jet, where as Tejas has just flown for the first time in the Bahrain Airshow.

 

[kaykay]

There are various reasons, may be PAF don't want to show full potential of aircraft or Pilot just shift its priority after achieving the target. But we don't have any doubt that JF17 can do Vertical take off. About JF17 takeoff please check this video on 2010 clearly show JF takeoff in 10 sec.

Bhai saab same can be said about Tejas. Ain't it? And about video, well when it appeared, it was already moving fast.

 

[AyanRay]

There are various reasons, may be PAF don't want to show full potential of aircraft or Pilot just shift its priority after achieving the target. But we don't have any doubt that JF17 can do Vertical take off. About JF17 takeoff please check this video on 2010 clearly show JF takeoff in 10 sec.

The jet was already on the move when the video started no not a good video to analyse. If you want to see a 10sec take off video look at this.

And remember this jet is on a training mission, its loaded with bombs and missiles and probably full tank too.

 

[Great Sachin]

There are various reasons, may be PAF don't want to show full potential of aircraft or Pilot just shift its priority after achieving the target. But we don't have any doubt that JF17 can do Vertical take off. About JF17 takeoff please check this video on 2010 clearly show JF takeoff in 10 sec.

Clever....JF17 was already running....we count 0 at stationary position not at already running position....failed again

But thanks for the video.....that shows that JF17 can not sustain vertical position at all

 

[My-Analogous]

Bhai saab same can be said about Tejas. Ain't it? And about video, well when it appeared, it was already moving fast.

About the video you are right it was move(nice observation which i didn't notice) and about LCA vertical takeoff i am not sure yet it can perform due to various reason and one will be first show so play safe and its a new bird and it will take time to gain confidence and may be they try that after two or three years but not before that. Vertical takeoff is a risky business and need time