Chronicle of DRDO/PSU missed targets & extended timelines
Re: Chronicle of DRDO/PSU missed targets & extended timeline
Continuing in my role as chronic "I suffer from all diseases" patient giving gyan on all manner of disease, I just had an "aha" moment based on what I have read in the media and articles.
The article by late cousin Suresh said that the MiG 21 tended to give no warning at all like shudder or vibration etc before stalling - and that could catch an unwary pilot by surprise.
The description of what happened with Sitara IIRC is that before stalling - it would go one wing down (or some such thing). In other words the Sitara is doing some funny stuff before stalling and giving a warning and saying "If you go any slower I will stall". Maybe (I have no information on this) the IJT simply rolls and dives and recovers from stall without spinning. Of course some planes can go into an unrecoverable tailspin - be nobody seems to know and nobody seems to be telling what the IJT does.
Given that we saw an image of IJT with tailchute - I just wonder why they do not simply take it up to 20,000 feet and stall it. Of course there is a risk of unexpected consequences and a crash. And the possibility of some injury to the pilot/s who punch out. But if there is another crash the media will write off the IJT. Gripens, Su 30s, J 15s, F-16s etc can crash as prototypes - but those planes are made by superior people - not like inferior us.
The article by late cousin Suresh said that the MiG 21 tended to give no warning at all like shudder or vibration etc before stalling - and that could catch an unwary pilot by surprise.
The description of what happened with Sitara IIRC is that before stalling - it would go one wing down (or some such thing). In other words the Sitara is doing some funny stuff before stalling and giving a warning and saying "If you go any slower I will stall". Maybe (I have no information on this) the IJT simply rolls and dives and recovers from stall without spinning. Of course some planes can go into an unrecoverable tailspin - be nobody seems to know and nobody seems to be telling what the IJT does.
Given that we saw an image of IJT with tailchute - I just wonder why they do not simply take it up to 20,000 feet and stall it. Of course there is a risk of unexpected consequences and a crash. And the possibility of some injury to the pilot/s who punch out. But if there is another crash the media will write off the IJT. Gripens, Su 30s, J 15s, F-16s etc can crash as prototypes - but those planes are made by superior people - not like inferior us.
Re: Chronicle of DRDO/PSU missed targets & extended timeline
Do any of the fighter jets do this? Mirage, Jaguar, LCA or Rafale?
Re: Chronicle of DRDO/PSU missed targets & extended timeline
This is not an answer, but while looking for an answer I found this pdf linked below and it is a terrific piece. I wanted to post excerpts but it is too long and very well written. I will post excerpts eventuallyramana wrote:Do any of the fighter jets do this? Mirage, Jaguar, LCA or Rafale?
http://www.dtic.mil/dtic/tr/fulltext/u2/a029071.pdf
Re: Chronicle of DRDO/PSU missed targets & extended timeline
BAE which is a consultant to HJT-36 is offering competing products both as IJT & AJT to IAF but am sure all their suggestions are fine, dandy and honest. In any case, HTT-40 is a fall back option for IJT.
Re: Chronicle of DRDO/PSU missed targets & extended timeline
What is the issue with HJT-36?
Does not stall? - Not possible but other issues can be:-
Stalls in unpredictable manner?
Does not spin?
Spins in unpredictable manner?
If stalls, cannot be recovered?
If spins, cannot be recovered?
Does not stall? - Not possible but other issues can be:-
Stalls in unpredictable manner?
Does not spin?
Spins in unpredictable manner?
If stalls, cannot be recovered?
If spins, cannot be recovered?
Re: Chronicle of DRDO/PSU missed targets & extended timeline
It seems like LCA saga. After 15 years we discover that radome is deficient. Now with HJT after 11 years we discover it cannot stall/spin.
Re: Chronicle of DRDO/PSU missed targets & extended timeline
Amidst all the rhona dhona :p, some interesting stuff here.
http://www.claws.in/images/events/pdf/1 ... il2014.pdf
Praise for DRDO from Army Generals, and ex signals head from Alpha Design tech & even the OFB gets a nod for the "tremendous" effort they showed for the Dhanush.
http://www.claws.in/images/events/pdf/1 ... il2014.pdf
Praise for DRDO from Army Generals, and ex signals head from Alpha Design tech & even the OFB gets a nod for the "tremendous" effort they showed for the Dhanush.
Re: Chronicle of DRDO/PSU missed targets & extended timeline
I wish you knew how much your posts shows that you don't understand the basics of aerodynamics. It also shows that you don't have the energy or inclination to find out the basics before writing this post (believe me, it is an half-an-hour job). But, you do have the time to criticize. Carry on, post count is an important thing.Gyan wrote:What is the issue with HJT-36?
Does not stall? - Not possible but other issues can be:-
Stalls in unpredictable manner?
Does not spin?
Spins in unpredictable manner?
If stalls, cannot be recovered?
If spins, cannot be recovered?
Re: Chronicle of DRDO/PSU missed targets & extended timeline
That is an interesting observation. If true it means that a plane that happens to resist spinning (which seems like a very good thing) would be unacceptable to the IAF. They want a plane that spins and recovers. Of all the things that HAL could have gone and done - they have ended up designing a plane that does not want to spin. The one feature that may make a plane safer and less scary to fly for a newbie is just the feature that the IAF does not want! How's that for Murphy's law at work?deejay wrote:^^^ Sid Sir, after the basic course, the 'spin' (IMV humble humble opinion) is an elimination step. Now I've come round to this view very recently.
Anyhow it appears that there is, in this day and age of fly-by-wire a tendency to try and design aircraft with software limits that will never allow the aircraft to stall and go into a spin - so that the pilot has the luxury of "carefree handling" and this reduces one more headache in the pilot's workload - the very headache I suspect that took the lives of dozens of young IAF pilots in MiG 21s. Isn't the Mirage 2000 like that onlee - I mean stalling limited by software? The LCA certainly is AFAIK.
Re: Chronicle of DRDO/PSU missed targets & extended timeline
It is very simple what IAF or any AF in the world wants from a trainer: It should be able to enter spin deterministically, and recover from it deterministically. If the recovery is not completed, there should be a fail safe. For example, in some planes lowering the undercarriage and retracting the flaps, leads to a recovery. All this should be possible at relatively low speed for novices, typically close to the stall speed at level flight (around 170 kmph).
For IJT, this is not happening. It is entering stall at 220 kmph from which it is recoverable. But if the plane is stalled at lower speeds it cannot be. There are two explanations:
1. At 170 kmph, IJT is flying at an AoA where the horizontal stab is stalled, because it is in the wake of the wing. Hence a recovery is impossible. However, they can enter a flat spin using accelerated stall, i.e. a stall entered at higher speeds while pulling some Gs. This does not require as high an AoA as the 1G stall. Therefore, the tailplane or part of it does not lie in the wake of the wing, so the recovery is possible.
2. To stall the IJT at 170 kmph, IJT requires the use of flaps. But then, the tailplane is in the wake and hence ineffective. Without the use of flaps, the plane stalls at 220 kmph, in which condition the plane is recover.
From the modifications that I have seen being made to the IJT, I very much suspect, it is case 1. Besides, if it was case 2, they could have as well made retraction of the flaps as part of the recovery process. The solution is to change the tail, which they are doing. Expect:
1. Either a lengthier tail, or a horizontal stabilizer with an anhedral or a tail with a LEX, or all the above.
2. Or an all moving tail, with or without LEXes),
3. Or a cruciform tail.
For IJT, this is not happening. It is entering stall at 220 kmph from which it is recoverable. But if the plane is stalled at lower speeds it cannot be. There are two explanations:
1. At 170 kmph, IJT is flying at an AoA where the horizontal stab is stalled, because it is in the wake of the wing. Hence a recovery is impossible. However, they can enter a flat spin using accelerated stall, i.e. a stall entered at higher speeds while pulling some Gs. This does not require as high an AoA as the 1G stall. Therefore, the tailplane or part of it does not lie in the wake of the wing, so the recovery is possible.
2. To stall the IJT at 170 kmph, IJT requires the use of flaps. But then, the tailplane is in the wake and hence ineffective. Without the use of flaps, the plane stalls at 220 kmph, in which condition the plane is recover.
From the modifications that I have seen being made to the IJT, I very much suspect, it is case 1. Besides, if it was case 2, they could have as well made retraction of the flaps as part of the recovery process. The solution is to change the tail, which they are doing. Expect:
1. Either a lengthier tail, or a horizontal stabilizer with an anhedral or a tail with a LEX, or all the above.
2. Or an all moving tail, with or without LEXes),
3. Or a cruciform tail.
Re: Chronicle of DRDO/PSU missed targets & extended timeline
Thanks for explaining.
Next question. Did the stall and spin a hard requirement when the AFR was written long ago?
Next question. Did the stall and spin a hard requirement when the AFR was written long ago?
Re: Chronicle of DRDO/PSU missed targets & extended timeline
It is a hard requirement, and there was no goal-shifting in this case.
Any trainer aircraft has to be easy to recover from spin as the student pilot can stall it by mistake.
I have always spoken strongly for desi products, and I am BIG supporter of IJT. But in its current form, it should not inducted into the IAF. It should be fixed quickly and deliveries started in 3-4 years (certainly possible). It is definitely not as big a deal as it is being made out to be. Handling deep stalls is part and parcel of aircraft design. Besides, the selection and the subsequent delivery of any imported trainer will also take atleast 3-4 years.
Any trainer aircraft has to be easy to recover from spin as the student pilot can stall it by mistake.
I have always spoken strongly for desi products, and I am BIG supporter of IJT. But in its current form, it should not inducted into the IAF. It should be fixed quickly and deliveries started in 3-4 years (certainly possible). It is definitely not as big a deal as it is being made out to be. Handling deep stalls is part and parcel of aircraft design. Besides, the selection and the subsequent delivery of any imported trainer will also take atleast 3-4 years.
Re: Chronicle of DRDO/PSU missed targets & extended timeline
can the hawk being a mature product be rigged to function as a IJT by programming more limits into its FCS and thrust controls?
in that case a subset of the hawks could be used as IJT.
(unlike other fighters, its engines have a very pleasant liquid warbling noise...)
in that case a subset of the hawks could be used as IJT.
(unlike other fighters, its engines have a very pleasant liquid warbling noise...)
Re: Chronicle of DRDO/PSU missed targets & extended timeline
I think that is what will be done as the last resort.
Re: Chronicle of DRDO/PSU missed targets & extended timeline
For a long time Kiran Mk1 was playing the role of IJT and Kiran Mk2 was playing the role of (sort of anyway) AJT. The big difference between the two was the engine power, Mk2 being the more powerful. There was some difference in the instrumentation too. So, Hawk as IJT would need some engine derating and I do not see the need for any other change. To me, it is more a question of putting pilots with less than 100 hrs experience on those machines.Singha wrote:can the hawk being a mature product be rigged to function as a IJT by programming more limits into its FCS and thrust controls?
in that case a subset of the hawks could be used as IJT.
(unlike other fighters, its engines have a very pleasant liquid warbling noise...)
I think with the HJT 36, the issue of stall needs to be looked as under:
Aircraft Certification: Certifying an aircraft which does not clearly lay down its stall speeds and stall characteristics. AFAIK, V (basic) or basic stalling speed is an absolute must on the maneuver envelope. There is a neat definition for the Basic Stalling speed which I did not find for quoting so this is from memory - The speed at which a stated aircraft of stated weight in clean configuration is unable to maintain straight and level flight is defined as its basic stalling speed. Further a stall for an aircraft may / can have identifiable characteristics prior to onset as in buffet etc. Aircraft (trainers) are also fitted with stall warning to warn the aircrew / pilot / trainee.
In case of HJT 36, that speed is not correctly defined as there is a wing drop which is different from stall as normally experienced. Hence, certifying the speed at which the stall happens may be a challenge.
Airforce Requirements: While training for Stall and Spin is most probably a requirement to equip trainees to handle such situations experienced inadvertently while in training or thereafter, it is Spin that is the bigger challenge. Stall and recovery may be sufficient for the intermediate stage as it may be carried out comprehensively in the basic stage itself. While this would deny the trainee an opportunity to Spin on a jet engined plane, the IJT may still enter service. The alternative being to scrap the intermediate stage totally in which case the non spin option is better. Even here the IJT must first stall properly and recover.
IMO, the IJT being developed by HAL has a negative and a positive:
Negative: Had ADA designed this or had been involved in it their experience and existing research in aerodynamics would have most probably spotted this problem of tail plane in wake of the wings earlier or even better, they would never have let it happen.
Positive: The HAL design bureau is a reality. Yes, they went wrong but we have two design bureaus now working on military planes. At least, HAL took the risk of trying to develop its own aircraft using its own expertise. There are many accusations of PSU's not capitalizing on know-how. Well, HAL tried.
Oh! there is this huge negative of IAF not having an IJT on time. I hope they fix it fast enough to stall it soon.
Re: Chronicle of DRDO/PSU missed targets & extended timeline
...meanwhile, as a counterpoint
http://idrw.org/f-35-engines-deemed-unr ... more-62666
F-35 Engines Deemed Unreliable by Government Accountability Office
http://idrw.org/f-35-engines-deemed-unr ... more-62666
F-35 Engines Deemed Unreliable by Government Accountability Office
and“Program data show that the reliability of the engine is very poor (less than half of where it should be) and has limited the program’s progress toward its overall reliability targets,” said the GAO report from earlier this month on the F-35 program’s “Affordability Challenges.”
The complex Marine Corps’ version of the F-35 was, as of December, flying 47 hours on average between engine failures, instead of the 90 hours expected by this point in the development process, GAO officials said. Air Force and Navy models’ engines flew about 25 hours instead of a projected 120.
The J-20, as we all know is fully ready to fly and fight as of yesterday.In another blow to the program’s reputation, the Defense Department’s director of operational testing, Michael Gilmore, testified that the F-35 would never be able to provide the kind of support for ground troops that the already 40-year-old A-10s deliver. Gilmore cited “digital communications deficiencies” as well as faults in the F-35’s threat detection systems.
Re: Chronicle of DRDO/PSU missed targets & extended timeline
^^^ Deejay
Your post confuses me:
I am quite sure the AF practises stalls with spins. If the plane is completely stalled but not in a flat spin, it will tumble around all over the place. I can't magine a fixed recovery sequence in such a case. AFAIK, the planes are always put into a flat-spin which is a stable configuration, i.e. the plane continues to be in a flat spin till the pilot recovers the plane, or the plane hits the ground. Therefore, all planes which are recoverable from a flat spin have a fixed recovery procedure. Also AFAIK, the test procedure is as follows. Reach a safe altitude and predefined speed, make the wings level, decrease the thrust to minimum, and then start increasing the AoA. Just before the plane is about to stall, provide slight rudder input. This stalls the plane and put it in a flat spin. The recovery is generally as follows, lower the nose towards the ground, and use rudder/aeliron to counter the spin. Whenever the flow reattaches with the wing bring the plane back to level flight accompanied with increase in engine thrust. So, your assertion that IJT should be used for 'stall' and not for 'spin' is misplaced IMHO.
Your post confuses me:
In level flight, what is a wing-drop, but a sign of onset of stall on one wing just before the other? Nose-over is extremely rare. If your wing drops consistently around (say) 200 kmph, that is your stall speed.deejay wrote: I think with the HJT 36, the issue of stall needs to be looked as under:
Aircraft Certification: Certifying an aircraft which does not clearly lay down its stall speeds and stall characteristics. AFAIK, V (basic) or basic stalling speed is an absolute must on the maneuver envelope. There is a neat definition for the Basic Stalling speed which I did not find for quoting so this is from memory - The speed at which a stated aircraft of stated weight in clean configuration is unable to maintain straight and level flight is defined as its basic stalling speed. Further a stall for an aircraft may / can have identifiable characteristics prior to onset as in buffet etc. Aircraft (trainers) are also fitted with stall warning to warn the aircrew / pilot / trainee.
In case of HJT 36, that speed is not correctly defined as there is a wing drop which is different from stall as normally experienced. Hence, certifying the speed at which the stall happens may be a challenge.
What is stall and recovery? Are you speaking of flying level with a high nose and no engine power, where the plane starts to lose altitude due to the loss of lift before the plane stalls completely? I don't think this interests the IAF at the intermediate training stage.Deejay wrote: Airforce Requirements: While training for Stall and Spin is most probably a requirement to equip trainees to handle such situations experienced inadvertently while in training or thereafter, it is Spin that is the bigger challenge. Stall and recovery may be sufficient for the intermediate stage as it may be carried out comprehensively in the basic stage itself. While this would deny the trainee an opportunity to Spin on a jet engined plane, the IJT may still enter service. The alternative being to scrap the intermediate stage totally in which case the non spin option is better. Even here the IJT must first stall properly and recover.
I am quite sure the AF practises stalls with spins. If the plane is completely stalled but not in a flat spin, it will tumble around all over the place. I can't magine a fixed recovery sequence in such a case. AFAIK, the planes are always put into a flat-spin which is a stable configuration, i.e. the plane continues to be in a flat spin till the pilot recovers the plane, or the plane hits the ground. Therefore, all planes which are recoverable from a flat spin have a fixed recovery procedure. Also AFAIK, the test procedure is as follows. Reach a safe altitude and predefined speed, make the wings level, decrease the thrust to minimum, and then start increasing the AoA. Just before the plane is about to stall, provide slight rudder input. This stalls the plane and put it in a flat spin. The recovery is generally as follows, lower the nose towards the ground, and use rudder/aeliron to counter the spin. Whenever the flow reattaches with the wing bring the plane back to level flight accompanied with increase in engine thrust. So, your assertion that IJT should be used for 'stall' and not for 'spin' is misplaced IMHO.
Re: Chronicle of DRDO/PSU missed targets & extended timeline
Yes, technically you are right that wing drop is the onset of stall and hence the speed should be taken as the basic stalling speed. However, in practice, if a wing drop is happening even at a small delta speed higher than predicted, then it is a problem. Unfortunately, it is the best explanation I can give presently. There is some literature on how a wing drop is different from the simultaneous stall of both wings but I do not have it presently. Give me some time and I will get the text.indranilroy wrote:^^^ Deejay
Your post confuses me:
In level flight, what is a wing-drop, but a sign of onset of stall on one wing just before the other? Nose-over is extremely rare. If your wing drops consistently around (say) 200 kmph, that is your stall speed.deejay wrote: I think with the HJT 36, the issue of stall needs to be looked as under:
Aircraft Certification: Certifying an aircraft which does not clearly lay down its stall speeds and stall characteristics. AFAIK, V (basic) or basic stalling speed is an absolute must on the maneuver envelope. There is a neat definition for the Basic Stalling speed which I did not find for quoting so this is from memory - The speed at which a stated aircraft of stated weight in clean configuration is unable to maintain straight and level flight is defined as its basic stalling speed. Further a stall for an aircraft may / can have identifiable characteristics prior to onset as in buffet etc. Aircraft (trainers) are also fitted with stall warning to warn the aircrew / pilot / trainee.
In case of HJT 36, that speed is not correctly defined as there is a wing drop which is different from stall as normally experienced. Hence, certifying the speed at which the stall happens may be a challenge.
And yes, the definition of Basic Stalling speed includes - "with throttle to idle" so thank you for adding it in your post.
Now in a practice for stall, this is how we would do in an HPT 32 (even in Kiran but the heights were different) - Climb to Xmtrs above ground. Establish level flight. Identify point of reference and point of orientation. Controls in neutral positions (rudder, stick). Checks before Stall competed - close throttle. Maintain level flight and let the speed wash off. Raise nose to keep level flight. As the speed approaches stalling speed, expect and experience wing buffet, stall warning light and noise comes on, aircraft stalls, nose drops, as the aircraft rushes to the ground (no tumbling, not even on Kirans) orient yourself, let the speed build up to Y kmph, open throttle, pull stick back, raise nose, establish climb in same direction, do after stall checks.
Now for spin climb to X+mtrs above gorund. In a spin at the time of entry, just prior to stall, one applies the rudder for the chosen direction of spin - i.e. right rudder for right spin or left rudder for left spin.
Again in a check (test) sortie if during stall, a wing drops, it would be better to repeat the stall or else either the pilot will be failed or the aircraft will not be cleared for aerobatics.
The bold part is the procedure for entry in to spin. Only the rudder would be full and in a smooth but quick movement. One can see the nose travel on the azimuth before the aircraft flips in to a spin.indranilroy wrote:What is stall and recovery? Are you speaking of flying level with a high nose and no engine power, where the plane starts to lose altitude due to the loss of lift before the plane stalls completely? I don't think this interests the IAF at the intermediate training stage.Deejay wrote: Airforce Requirements: While training for Stall and Spin is most probably a requirement to equip trainees to handle such situations experienced inadvertently while in training or thereafter, it is Spin that is the bigger challenge. Stall and recovery may be sufficient for the intermediate stage as it may be carried out comprehensively in the basic stage itself. While this would deny the trainee an opportunity to Spin on a jet engined plane, the IJT may still enter service. The alternative being to scrap the intermediate stage totally in which case the non spin option is better. Even here the IJT must first stall properly and recover.
I am quite sure the AF practises stalls with spins. If the plane is completely stalled but not in a flat spin, it will tumble around all over the place. I can't magine a fixed recovery sequence in such a case. AFAIK, the planes are always put into a flat-spin which is a stable configuration, i.e. the plane continues to be in a flat spin till the pilot recovers the plane, or the plane hits the ground. Therefore, all planes which are recoverable from a flat spin have a fixed recovery procedure. Also AFAIK, the test procedure is as follows. Reach a safe altitude and predefined speed, make the wings level, decrease the thrust to minimum, and then start increasing the AoA. Just before the plane is about to stall, provide slight rudder input. This stalls the plane and put it in a flat spin. The recovery is generally as follows, lower the nose towards the ground, and use rudder/aeliron to counter the spin. Whenever the flow reattaches with the wing bring the plane back to level flight accompanied with increase in engine thrust. So, your assertion that IJT should be used for 'stall' and not for 'spin' is misplaced IMHO.
The recovery from a spin for HPT was simple - neutralise the controls and she would come off it. The Kiran would sometimes require an opposite control input. The challenge is to remember the turns completed and direction of spin. It is fairly disorienting.
Since the two were practiced separately even on Kiran, I think it is possible to use the IJT for stall and not for spin.
Re: Chronicle of DRDO/PSU missed targets & extended timeline
Just as a FYI, here is Audi making Diesel from water and air:Why the hate? This technology if proven in India has major export potential to western countries that already do the manual labour of collecting and separating plastic from trash for recycling purposes. In fact it has export potential to nearly every country in the world that's currently trying to generate energy from their trash. The Europeans are also trying to do similar things, and are probably ahead in this field, and while they get applauded for their efforts in their country and the world, when indians try the same, we get only insults from other indians.
Audi just created diesel fuel from air and water
The company's pilot plant, which is operated by German startup Sunfire in Dresden, produced its first batches of the "e-diesel" this month. German Federal Minister of Education and Research Johanna Wanka put a few liters of the fuel in her work car, an Audi A8, to commemorate the accomplishment.
The base fuel is referred to as "blue crude," and begins by taking electricity from renewable sources like wind, solar or hydropower and using it to produce hydrogen from water via reversible electrolysis. The hydrogen is then mixed with CO2 that has been converted into CO in two chemical processes and the resulting reactions produce a liquid made from long-chain hydrocarbons – this is blue crude, which is then refined to create the end product, the synthetic e-diesel.
Audi says that the carbon dioxide used in the process is currently supplied by a biogas facility but, further adding to the green impacts of the process, some of the CO2 is captured directly from the ambient air, taking the greenhouse gas out of the atmosphere.
ADVERTISEMENT
Sunfire claims that analysis shows the properties of the synthetic diesel are superior to fossil fuel, and that its lack of sulphur and fossil-based oil makes it more environmentally friendly. The overall energy efficiency of the fuel creation process using renewable power is around 70 percent, according to Audi.
"The engine runs quieter and fewer pollutants are being created," says Sunfire CTO Christian von Olshausen.
The fuel can be combined with conventional diesel fuel, as is often done with biodiesel fuels already.
The Dresden pilot plant is set to produce about 42 gallons (160 l) of synthetic diesel per day in the coming months, and the two companies say the next step is to build a bigger plant.
"If we get the first sales order, we will be ready to commercialize our technology," von Olshausen says.
Sunfire anticipates that the market price for the synthetic diesel could be between 1 and 1.5 Euros per liter, which would be nearly competitive or a little more expensive than current diesel prices in Europe, but the actual figure will be largely dependent on the price of electricity.
For an overview of the production process, check out the promotional video below.
Re: Chronicle of DRDO/PSU missed targets & extended timeline
Deejay,
Thank you for your clarifications. So by stall, you did not mean complete stalling. You meant partial loss of lift, leading to nose-down moment. I am pretty sure that IJT can do it too. But to do it at very low speed, I think it would require a little more washout. I have seen them playing with wing fences and recently with vortex generators. I don't know if that solves the problem.
But if the plane gets into a deep stall in flat spin, it cannot be allowed to enter service. Imagine you are close to stall, and a gust of wind puts you in a flat spin, or there is an inadvertant rudder input. This, at the very least, leads to a plane lost, and the very worst, leads to the loss of an instructor and a trainee.
Thank you for your clarifications. So by stall, you did not mean complete stalling. You meant partial loss of lift, leading to nose-down moment. I am pretty sure that IJT can do it too. But to do it at very low speed, I think it would require a little more washout. I have seen them playing with wing fences and recently with vortex generators. I don't know if that solves the problem.
But if the plane gets into a deep stall in flat spin, it cannot be allowed to enter service. Imagine you are close to stall, and a gust of wind puts you in a flat spin, or there is an inadvertant rudder input. This, at the very least, leads to a plane lost, and the very worst, leads to the loss of an instructor and a trainee.
Re: Chronicle of DRDO/PSU missed targets & extended timeline
^ That would be catastrophic. I guess we must wait till the stall issues are sorted out.
Re: Chronicle of DRDO/PSU missed targets & extended timeline
Flat spin is mostly unrecoverable, isn't it? Flat spin = pure rotation about vertical axis passing through the jet; normal spin = helical downward spiral motion about vertical axis.indranilroy wrote:Deejay,
Thank you for your clarifications. So by stall, you did not mean complete stalling. You meant partial loss of lift, leading to nose-down moment. I am pretty sure that IJT can do it too. But to do it at very low speed, I think it would require a little more washout. I have seen them playing with wing fences and recently with vortex generators. I don't know if that solves the problem.
But if the plane gets into a deep stall in flat spin, it cannot be allowed to enter service. Imagine you are close to stall, and a gust of wind puts you in a flat spin, or there is an inadvertant rudder input. This, at the very least, leads to a plane lost, and the very worst, leads to the loss of an instructor and a trainee.
Do they go for flat spin on trainers?? I thought its only erect spin.
Re: Chronicle of DRDO/PSU missed targets & extended timeline
There is the spiral dive where both wings are flying. Then there is the condition where the inside wing has stalled, but the outside wing is flying, this leads to autorotation about an axis outside the plane. Then there is flat spin where both wings have stalled and the plane autorotates around its own axis.
Possible recovery depends on the plane, i.e. placement of CG and effectiveness of the tail.
Possible recovery depends on the plane, i.e. placement of CG and effectiveness of the tail.
Re: Chronicle of DRDO/PSU missed targets & extended timeline
Re Deejay
Can you comment whether LCA is suitable to be developed as AJT, say, 10 years down the road, when Hawk will need replacement? Thanx in adv.
Can you comment whether LCA is suitable to be developed as AJT, say, 10 years down the road, when Hawk will need replacement? Thanx in adv.
Re: Chronicle of DRDO/PSU missed targets & extended timeline
Gyan, No LCA can't be developed as it is an unstable platform. Trainee pilots need a stable platform.
However LCA type of avionics etc. can be used in a new design as Hawk replacement.
However with IAF mind set unless its named Eagle and imported it wont procure them.
However LCA type of avionics etc. can be used in a new design as Hawk replacement.
However with IAF mind set unless its named Eagle and imported it wont procure them.
Re: Chronicle of DRDO/PSU missed targets & extended timeline
@nileshjr you are right, only errect spin. On HPT 32 it was more like a downward spiral, slightly more violent and tightening corkscrew for Kiran's.
@Gyan: ramana sirs post is concise and apt.
@Gyan: ramana sirs post is concise and apt.
Re: Chronicle of DRDO/PSU missed targets & extended timeline
Hawk retirement in 10 years? Heck I am still toasting the decision made and arrival of AJT!Gyan wrote:Re Deejay
Can you comment whether LCA is suitable to be developed as AJT, say, 10 years down the road, when Hawk will need replacement? Thanx in adv.
Tejas could be a Lead In Fighter Trainer I suppose. Just like MiG 21 was (is?)
Re: Chronicle of DRDO/PSU missed targets & extended timeline
Ramana this issue of unstable thingie was first raised by Shiv long time back and concensus was that it was a non issue
Re: Chronicle of DRDO/PSU missed targets & extended timeline
The defence services had bought indigenous equipment worth Rs 31,503 crore in 2013-14 while they imported items to the tune of Rs 35,006 crore.
When it comes to supplying equipment to the armed forces, all the Defence Public Sector Undertakings (DPSU) have a poor record of delivery. Against an order of 180 Su30MKI aircraft by 2013-14, Hindustan Aeronautics Limited (HAL) has produced only 150 aircraft. HAL has produced only 78 ALH helicopters when it was supposed to supply 138 helicopters by 2013-14.
The government has identified 73 roads as strategic India-China border roads. The Border Roads Organisation (BRO) was supposed to complete 61 strategic roads — with a total length of 3,410 km — on the Chinese border by 2012, but has completed only 19 roads of 625 km length so far. Work on two roads has not even started due to pending wildlife clearance and approval of alignment from the Home Ministry.
The BRO told the committee 16 of these strategic roads are likely to be completed this year while 13 roads will be completed in 2016, and 9 in 2017.
Link: http://indianexpress.com/article/india/ ... ign=buffer
Re: Chronicle of DRDO/PSU missed targets & extended timeline
Yes, but Su-30 MKI is more of a case of Russian OEM screwing up on TOT
See the CAG report.
See the CAG report.
Re: Chronicle of DRDO/PSU missed targets & extended timeline
x-posting:
Some plain talking by Dr Dathan, who might have been awake during the 90s "Ruskie CABS" saga, wherein LPSC finally TESTED the engine design to figure out the issues that russians could not. Loss of years from this and spy scandal!!
Meet on aerospace systems begins
Some plain talking by Dr Dathan, who might have been awake during the 90s "Ruskie CABS" saga, wherein LPSC finally TESTED the engine design to figure out the issues that russians could not. Loss of years from this and spy scandal!!
Meet on aerospace systems begins
The tendency to have implicit faith in foreign equipment is a probable cause for the system failure in aircraft and rocket flights, VSSC Director M.C. Dathan has said.
This misplaced confidence results in the failure to test foreign components, he said, while inaugurating the two-day National Conference on Health Monitoring and Fault Detection in Aerospace Systems which began on Friday under the auspices of the Astronautical Society of India (ASI). “The foremost reason for the failure of complex flight systems is not having a full understanding on how they work. We may be able to operate systems well, but a thorough inside knowledge of the system will be missing,” Mr. Dathan said.
He observed that a key aspect of the success of ISRO’s first Mars mission was the enormous amount of data analyses done to find out what went wrong on previous Mars missions and the meticulous precautions taken to prevent such failures.
P.S. Subramanyam, Director, Aeronautical Development Agency, called for better interaction between aviation and space technology experts for development of appropriate technologies.
Re: Chronicle of DRDO/PSU missed targets & extended timeline
Guess which scion was in charge when all this happened? Will make it clear why we kept importing TATRAs over TATA, and how our current system came about and why it was created that way.
Col AG Thomas, EME, DRDO
Writing in DSA, Jan 2015
PRIVATE SECTOR IN DEFENCEWhy Private Sector?
The foundation of our defence industries was laid
during the mid 60s after the humiliating encounter
with the Chinese. It took root, started to sprout
well with the Services and the industry working
together in harmony. Humble but meaningful
projects were undertaken which started bearing
fruit by the late 70s. However from the mid 80s
onwards MoD took a series of decisions as if it had
made up its mind to destroy our defence industries.
This includes untimely cancellation of promisinprojects at HAL, closing down of small units like the
Gun Development Team, Jabalpur without
any reason and stopping the intake of
Permanently Seconded Service Offi cers (PSSO)
to DRDO. Over a period of time the trust link
between the Services and industry was lost.
MoD pursued a policy of indiscriminate off the
shelf purchase of weapon systems from abroad,
which further demoralised and destroyed
the indigenous capabilities.
Col AG Thomas, EME, DRDO
Writing in DSA, Jan 2015
Re: Chronicle of DRDO/PSU missed targets & extended timeline
This is weird news that bears long term follow up:
GTRE issues tender to manufacture 20 80 kN thrust class engines
So what does this mean?
1. GTRE already has a readymade engine and wants to involve private sector in assembly and mfg
or
2. GTRE has signed a deal with an existing engine maker with a known engine design and is simply looking for Indian partners
I would be happy if this news is an oblique resurrection of Kaveri. But they say Kaveri is dead.
What is going on? "Expression of Interest" sounds like testing the waters that will go on for the next 2 years any way.
GTRE issues tender to manufacture 20 80 kN thrust class engines
"manufacturing and asssembly" of 20 engines in the next 3-4 years?Gas Turbine Research Establishment (GTRE) on 15-06-2015 has issued Tender seeking Expression of Interest (EOI) from reputed Indian private / public sector industries / organisations for manufacturing and assembly of 80 kN thrust class engine consisting about 20000 number of components and parts.
Tender document which idrw.org has gone though informs that GTRE is developing an aero gas turbine engines, with an objective of manufacturing and assembly of 80 kN thrust class engine prototypes (20 engines) over a period of 3-4 years.
So what does this mean?
1. GTRE already has a readymade engine and wants to involve private sector in assembly and mfg
or
2. GTRE has signed a deal with an existing engine maker with a known engine design and is simply looking for Indian partners
I would be happy if this news is an oblique resurrection of Kaveri. But they say Kaveri is dead.
What is going on? "Expression of Interest" sounds like testing the waters that will go on for the next 2 years any way.
-
- BRFite
- Posts: 1852
- Joined: 11 Aug 2016 06:14
Re: Chronicle of DRDO/PSU missed targets & extended timeline
Kaveri is not dead - just 're-purposed"
Re: Chronicle of DRDO/PSU missed targets & extended timeline
From what I have heard Kaveri pretty much reached its target of 80 kN. Producing 20 is a great idea and I hope funding is there. they should at least put on UAVsprasannasimha wrote:Kaveri is not dead - just 're-purposed"
-
- BRF Oldie
- Posts: 2022
- Joined: 11 Aug 2016 06:14
Re: Chronicle of DRDO/PSU missed targets & extended timeline
^Can we also replace the crappy russian engines with the kaveri on the Mig-29?
-
- BRFite
- Posts: 1852
- Joined: 11 Aug 2016 06:14
Re: Chronicle of DRDO/PSU missed targets & extended timeline
While people may crib about Kaveri I have hard a different saga with test beds not being given, Alloy requirements not being allowed because volumes are not sufficient etc etc which impeded development. This was acomplex play of financial and geopolitics which was played to prevent and stall its development.
Re: Chronicle of DRDO/PSU missed targets & extended timeline
I wonder if this is because GTRE is a separate establishment that has no connection with Aircraft designer ADA and manufacturer HAL. The splitting of what should be well coordinated can be made much worse by government employed executives in each of these organization who are looking to rule their own domain and acquire personal prestige rather than work towards a coordinated end for the nation.prasannasimha wrote:While people may crib about Kaveri I have hard a different saga with test beds not being given, Alloy requirements not being allowed because volumes are not sufficient etc etc which impeded development. This was acomplex play of financial and geopolitics which was played to prevent and stall its development.
The question that comes to mind is, what if GTRE produces 20 engines. What are they going to do with them? Does HAL want them? Does ADA want them? Does IAF want them? These are mysteries thrown up by the news item that GTRE is looking to produce 20 engines.
I wonder - is this news or some random snippet posted to fill space in by the news provider
Re: Chronicle of DRDO/PSU missed targets & extended timeline
Probably a dumb question, is there any private org in India that could build an aircraft around kaveri, either a single engined or twin if the thrust is inadequate? Could leverage tech developed for Tejas ( fwb etc. without the extra fancy stuff) on license basis.