rrao wrote:what is ailing with IJT?
1. wrong decsion to replace LARZAC with AL-55I
2. Russians ditching HAL to deliver a proven and reliable AL-55I in time ?
3 . flaws in the Aerodynamics design ,which is apparently causing an unwanted roll during stall tests?
4. Flight control systems are too lazy to respond?
5 .HAL has roped in BAe to help cllear IJT...how useful is it?
6. Retirement of project heads who conceived it?
7.new vigilance procedures have made the lives of designers miserable. Procurement is a nightmare with single tender issues,re-tendering and re-tendering causing an endless cycle..
8.of-course project management!!!
1 and 2. They had to go for a bigger engine. Going for AL-55I was certainly a mistake in hindsight. But at the time the decision was made, it did look quite good on paper.
3. Where did you read this? I have never read about uncommanded roll. What I have read is that during spins, the control surfaces are not effective enough to get out of the stall. But this is 1 year old news now. They have shed the vortex generators on the nose and the fences on the wings, and added vortex generators on the wings and also made them ribbed. They have fitted spin chutes and the tests have continued. We should wait for the test results.
4. Never heard of this before.
6. Why? They took a bold initiative and we are going to go witch hunting with the benefit of hindsight?!!
7 and 8. No comments.
rrao wrote:IJT design is it based on Alpha jet or a polish trainer? The air intakes are too small which may make the engine starved of the critical oxygen during high "g: Maneuvers?The wing length and dimension appeared to be too small !!! The location of air intakes should it be above or below the wings for an optimal flight performance. IJT was hurriedly conceived in 36 months because of which it is suffering from congenital maladies...Gurus please comment on the soundness of the IJT design..
what are the corrective actions which our learned gurus can indicate .TIA!!!!
I have never heard of the IJT design to be based on anything. I have no idea on what basis you think the intakes are small (I have nothing more to add to what Raman sir said). For example this is the Hawk, the most successful jet trainer with an engine 1.5 times the size of IJT.
Longer wing span is bad for maneuverability. I have never head of anything regarding insufficient maneuverability owing to wing loading. It is a simple design (exactly what it should be for a subsonic trainer). Intakes work best when they are away from any part of the body (including the wing) to avoid any buzz from the boundary layers. People place it under the wing or body of jet fighters for high alpha manuevers, so that the wing/body rams some incoming air into the air intake. This is not ideal but better than insufficient air. But not all jets do that (Mirage 2000, Mig-21, F-22, Gripen, Jaguars to name a few). I have never heard of IJT being starved of air.
15 years for design and certification along with an engine change is actually still good. There is urgency within the team. We should be a little more patient.