LCA Tejas: News and Discussions

sanjaykumar · Post by **sanjaykumar** » 23 Jan 2016 05:59

Spectacular aviation display, the relaxed stability/FBW comes through very well.
Itlives up to its name in Urdu-tezas.

shiv · Post by **shiv** » 23 Jan 2016 06:04

Asit P wrote:Some observations that I made are:

1). It is small and very swift, as a result of which, it was difficult to capture its shots in camera in comparison to the other aircrafts
2). The diameter of 360 degree loop made by Tejas was shorter than that of F 16 & Mirage 2000 (naked eye observation)
3). The part of runway it took to take off was also shorter than the above mentioned birds (again naked eye observation)
4). Unlike the Sarang display team, there was very little awareness about this bird in the general public (Indians included). Unfortunately, the live commentary went off today owing to some technical snag just before Tejas took off to the skies,for the want of which, many people were left wondering as to which aircraft it is. I heard many people say that its a Saudi plane. One champion went on to say that it was JF 17
5). Purely from the perspective of engaging the audience, bulk of which comprises of kids and those who have very little awareness about defense products, Tejas must use colored smoke instead of White.

Asit P my compliments. these are the types of high value observations that separate the men from the boys - the plane-watchers from the connoisseurs

member_29172 · Post by **member_29172** » 23 Jan 2016 06:08

sanjaykumar wrote:Spectacular aviation display, the relaxed stability/FBW comes through very well.
Itlives up to its name in Urdu-tezas.

Tejas is Sanskrit for enlightened one or "the bright one"

shaun · Post by **shaun** » 23 Jan 2016 06:11

Wish Tejas now give demo with its full weapon and sensor payloads in A2A configuration.

shiv · Post by **shiv** » 23 Jan 2016 06:12

In a remarkable act of originality, Indian Express has sent a man with a cellphoe to Bahrain. That said - at least one of the square loops is seen well
https://www.youtube.com/watch?v=sDUVgy151ng

shiv · Post by **shiv** » 23 Jan 2016 06:13

Shaun wrote:Wish Tejas now give demo with its full weapon and sensor payloads .

A flying demo with all that will be insipid in any aircraft because of all the extra weight.

Kartik · Post by **Kartik** » 23 Jan 2016 06:30

thanks for the pics Asit

shaun · Post by **shaun** » 23 Jan 2016 06:35

shiv wrote:
Shaun wrote:Wish Tejas now give demo with its full weapon and sensor payloads .
A flying demo with all that will be insipid in any aircraft because of all the extra weight.

Jingo heart will always ask for more !

Vivek K · Post by **Vivek K** » 23 Jan 2016 07:05

As it - those are photos to die for.

member_23365 · Post by **member_23365** » 23 Jan 2016 07:25

Congrats to Tejas team for such a stellar performance. The low pass vertical pull was really amazing.
But the real achivement will be the day it gets inducted in IAF.

Singha · Post by **Singha** » 23 Jan 2016 07:40

will tejas also incorporate smaller pointier supersonic drop tanks for A2A missions vs the ones we see now?

Hobbes · Post by **Hobbes** » 23 Jan 2016 07:55

shiv wrote:In a remarkable act of originality, Indian Express has sent a man with a cellphoe to Bahrain. That said - at least one of the square loops is seen well
https://www.youtube.com/watch?v=sDUVgy151ng

A caption towards the end of the clip credits DRDO for it.

Baikul · Post by **Baikul** » 23 Jan 2016 08:28

Asit P, many thanks for your pictures. They are all great, but the first two on page 34 are stunning. Especially the one with the winding road in the background, that image seems to leap off the page. I suggest you watermark them.

ramana · Post by **ramana** » 23 Jan 2016 08:43

AsitP,
Awesome eyewitness report and pictures.

Thanks a lot for them.

I liked the short runway description which gives an idea of thrust to power and the turn radius which gives an idea of gs and maneuverability in combat.

Once again kudos for observing the essentials.

shaun · Post by **shaun** » 23 Jan 2016 08:47

AsitP ....you better put watermark .....fabulous , fantastic , those pics ..carry on the good work .

21st and 22nd demo was at same time schedule ??

deejay · Post by **deejay** » 23 Jan 2016 09:22

Asit ji please immediately watermark your pictures.

Beautiful shots. Thanks for sharing.

ArmenT · Post by **ArmenT** » 23 Jan 2016 10:48

Nice pictures. As a side note, I think this must be the first time that the LCA was seen without any sensors taped to various parts of the wings -- that's fantastic for sales pitches

.

shiv · Post by **shiv** » 23 Jan 2016 14:02

Hobbes wrote:
shiv wrote:In a remarkable act of originality, Indian Express has sent a man with a cellphoe to Bahrain. That said - at least one of the square loops is seen well
A caption towards the end of the clip credits DRDO for it.

That is the second half - which was arguably worse.

Meanwhile - I hope this works : Left side- LCA 2011, Rt side LCA 2016 In Bahrain LCA goes beyond top of loop in less than 9 sec which is the 2011 time

shaun · Post by **shaun** » 23 Jan 2016 14:35

todays tejas demo at 15:40 bahrain std time , IST SHOULD BE 18:10

member_27581 · Post by **member_27581** » 23 Jan 2016 15:07

Tejas updates:
1. Tejas Mk-1A might get Astra BVR while and N-LCA will get the Derby. Integration of both Python-5 and Derby are ongoing on Mk-1 but its unclear which one will be tested in the upcoming trial.
2. Cobham radome integration and ground tests over. Flight test will begin soon.
3. IFR probe integration and ground testing ongoing.
4. Mk-1 will not have an operational gun for FOC. IAF isn't giving priority to gun operationalization for now. "Butt firing" tests have been completed and preliminary structural modifications done. Work to be completed post FOC.
5. Undercarriage issue partly responsible for the SP airframes rollout delay. The issue has been temporarily fixed.
6. LSP-7 will undertake the BVR trials at Jamnagar after returning from BIAS.
7. First 20 Mk-1 airframes will be in FOC configuration, while the next 100 will be in Mk-1A configuration
8. Total number of airframes targeted to be produced within this year is 6.

From a Tejas Facebook page

shiv · Post by **shiv** » 23 Jan 2016 16:27

Someone please tell me why it would be erroneous to calculate AoA from this image? So what is the AoA of the Tejas in this low speed high AoA pass (Screen grab of display in Bahrain)

Nick_S · Post by **Nick_S** » 23 Jan 2016 16:50

Zynda · Post by **Zynda** » 23 Jan 2016 16:58

< Wrong answer

>

shaun · Post by **shaun** » 23 Jan 2016 17:23

dhuuuu...bahrain TV is showing magic in between shows

could capture only one and half minute of tejas

SaiK · Post by **SaiK** » 23 Jan 2016 17:23

I almost thought the canards were on the tejas.

abhik · Post by **abhik** » 23 Jan 2016 18:17

shiv wrote:Someone please tell me why it would be erroneous to calculate AoA from this image? So what is the AoA of the Tejas in this low speed high AoA pass (Screen grab of display in Bahrain)

Can't comment on calculating AoA using the angle of the smoke, but even if it was valid you would have to know what angle the picture was taken vis a vis the direction of the aircraft. If the aircraft was moving perpendicular to the viewer's line of sight then you would get the true angle, if it was moving along the line of sight the angle would always appear to be 90degrees.

shaun · Post by **shaun** » 23 Jan 2016 18:22

3rd day demo

SaiK · Post by **SaiK** » 23 Jan 2016 18:35

^didn't work for me

SriKumar · Post by **SriKumar** » 23 Jan 2016 18:37

abhik wrote:
shiv wrote:Someone please tell me why it would be erroneous to calculate AoA from this image? So what is the AoA of the Tejas in this low speed high AoA pass (Screen grab of display in Bahrain)
Can't comment on calculating AoA using the angle of the smoke, but even if it was valid you would have to know what angle the picture was taken vis a vis the direction of the aircraft. If the aircraft was moving perpendicular to the viewer's line of sight then you would get the true angle, if it was moving along the line of sight the angle would always appear to be 90degrees.

Will the true angle will be more than than angle calculated from the picture? Or will it be less?

shiv · Post by **shiv** » 23 Jan 2016 18:43

abhik wrote:
shiv wrote:Someone please tell me why it would be erroneous to calculate AoA from this image? So what is the AoA of the Tejas in this low speed high AoA pass (Screen grab of display in Bahrain)
Can't comment on calculating AoA using the angle of the smoke, but even if it was valid you would have to know what angle the picture was taken vis a vis the direction of the aircraft. If the aircraft was moving perpendicular to the viewer's line of sight then you would get the true angle, if it was moving along the line of sight the angle would always appear to be 90degrees.

If the aircraft was level with the observer's eye the angle between the axis of the aircraft and the airflow (smoke) should be AoA - at least that is my understanding

If the observer is directly below the aircraft no angle would be seen - only a straight line. At any level in between the two positions, the angle seen should be less than the true angle. That means that the angle I have actually measured from the image is less than the actual angle of attack. And guess what - I am getting 35 degrees from the image.

Why is this wrong?

chilarai · Post by **chilarai** » 23 Jan 2016 19:09

shiv wrote: If the observer is directly below the aircraft no angle would be seen - only a straight line.

If the observer is directly below you can probably have a better approximation of the angle of attack , the aspect ratio ( wing tip to wing tip vs head to tail ) of the pic would change with the angle of attack and should be fairly accurate IMO.

manjgu · Post by **manjgu** » 23 Jan 2016 19:22

trying to deduce AoA from pics is good try but frankly hilarious... we should wait for tech specs..

shiv · Post by **shiv** » 23 Jan 2016 19:28

manjgu wrote:trying to deduce AoA from pics is good try but frankly hilarious... we should wait for tech specs..

Why is it hilarious? It is a simple science question. Hilarious is for arts boys

shiv · Post by **shiv** » 23 Jan 2016 19:29

chilarai wrote: If the observer is directly below you can probably have a better approximation of the angle of attack , the aspect ratio ( wing tip to wing tip vs head to tail ) of the pic would change with the angle of attack and should be fairly accurate IMO.

Could you explain that please?

shaun · Post by **shaun** » 23 Jan 2016 19:31

Tejas

Sarang

shiv · Post by **shiv** » 23 Jan 2016 19:37

It is possible that no one on here knows what angle of attack actually means - and I include myself in that. But I think I do, so I want to know why the angle between the long axis of the smoke generator and the approximate axis of the trailing smoke does not reflect the angle of attack in level flight. The plane is flying level at slow speed.

This may be a good opportunity to find out what we all like to howl about and ask a lot of intelligent sounding questions about

SidSom · Post by **SidSom** » 23 Jan 2016 19:46

Oh Wow... Am I really going to attempt this... (Please be kind, I am no expert on this).

The vector defining the air flow direction is simple to define from the foto. But the zero angle of attack line/wing chord line itself is not simple to define. This many times is not parallel to the wing as the wing itself may have a twist. (Dunno the details of Tejas to comment). So that could induce error into the calc.

member_28108 · Post by **member_28108** » 23 Jan 2016 19:58

Shiv the problem of determining the angle of attack from that picture is that we need to have the profile of the plane to determine the actual long axis chord of the aerfoil and the flow direction (relative wind). So when angulated you will have an error due to parallax. So since the plane has been angulated in 3 planes your angle of the pod can be significantly different from the true"inclination' of the wing based on your viewing angle.dd to this the direction of airflow. this is how a cylindrical object can vary from a circle to oval to square based on how each end gets inclined. Same for projections of angles. If you were to project this on to 3 planes you could calculate it. In fact that is what is done by engineers when doing an engineering drawing to eliminate the errors that occur when you project a 3D object onto a 2D surface.
Actually something like this happens in both echocardiography and coronary angiography where foreshortening of an object can occur changing measurements radically unless we make multiple measurements of each side en-face to get a flattened 2D "structure" thus eliminating parallax along one axis at a time.

Akshay Kapoor · Post by **Akshay Kapoor** » 23 Jan 2016 20:03

manjgu wrote:trying to deduce AoA from pics is good try but frankly hilarious... we should wait for tech specs..

Atleast he has a spirit (much needed in our country) to hands on practical stuff, invent and do it yourself. Thats what makes those comparison videos and air tunnel examples using pressure cookers. I find your comment not hilarious but sad.

SidSom · Post by **SidSom** » 23 Jan 2016 20:04

prasannasimha wrote:Shiv the problem of determining the angle of attack from that picture is that we need to have the profile of the plane to determine the actual long axis chord of the aerfoil and the flow direction (relative wind). So when angulated you will have an error due to parallax. So since the plane has been angulated in 3 planes your angle of the pod can be significantly different from the true"inclination' of the wing based on your viewing angle.dd to this the direction of airflow. this is how a cylindrical object can vary from a circle to oval to square based on how each end gets inclined. Same for projections of angles. If you were to project this on to 3 planes you could calculate it. In fact that is what is done by engineers when doing an engineering drawing to eliminate the errors that occur when you project a 3D object onto a 2D surface.
Actually something like this happens in both echocardiography and coronary angiography where foreshortening of an object can occur changing measurements radically unless we make multiple measurements of each side en-face to get a flattened 2D "structure" thus eliminating parallax along one axis at a time.

Is there a ELI5 (Explain like I am 5) version of your answer