Key points from the presentation.Indranil wrote:
***Clearances and Certification
- HTT-40 Specifications:
# Length = 11.3m
# Span = 11m
# Height = 3.7m
# Take-off Weight = 2800kg
# Internal Fuel = 450kg
# TO roll at SL = 1000m
# Landing roll at SL = 1000m
# Max speed CAS at SL = 400kmph
# Stall speed = 140kmph
# Service ceiling = 6000m
# Ferry Range = 1000km
- Certification Challenges for HTT-40
# Stringent timelines to meet user requirements
# Emphasize on Analysis and Simulation for System Clearance
# Evaluation of Stall and Spin characteristics using mathematical models
# Non-availability of Certification documents from (LRU) OEMs due to IPR issues or high documentation costs.
- LRU Certification: Total 80 Indian LRUs and 65 imported LRUs were certified. LRU Certification was challenge since for some Qualification Testing documentation was not available or OEM were not willing to share. In some cases, if same LRUs were on other certifies systems performance from those was considered for certification for HTT-40.
- Aircraft System Certification: Total of 13 Aircraft systems to be certified. Lot of challenges here as well. Static Test specimen was not available, thus actual prototype wings were used for testing and then fitted to the prototype (proposal accepted with certain envelop restrictions). Unacceptable neck loaded for front seat during ejection for smaller pilots, thus restriction imposed for than <70 percentile pilots.
# Aerodynamics
# Avionics
# Environmental Control System
# Electric System
# Escape System
# Flight Control System
# Fuel system
# Hydraulics system
# Landing Gear System
# Life Support System
# Power plant
# Structures
# Communication and navigation System
-Aircraft First Flight Clearance: On 15th May 2016, First flight clearance was issued and on 31st May 2016, the First flight was conducted.
***Design and Development
-Till date, no proactive steps from HAL on BTA development. HAL used to wait for approvals and funding. HTT-40 was a different case, where HAL went ahead with the development by putting money from onw pocket and without any commitment from IAF whatsoever.
- Completion of Design to First Flight - within 11 months
- Confirmed order of ~70 BTA from IAF now
- CEMILAC was more of a Design partner than just a Certification Agency
- With typical approach it would have taken 10yrs for entire development, which is a worldwide norm. But with CEMILAC onboard right from proposal writing stage, the time for certification reduced considerably.
-Preliminary Design took ~6months. HAL waited for formal approval from IAF for 2yrs, but it never came. Thats when HAL decided to go ahead on its own in May 2013 by investing 300Cr from own pocket. Detail design took 2yrs i.e. till May 2015. And within 11month thereon, first flight took place. Now certification is expected by end of 2018 and starting of deliveries to IAF are expected by 2019.
- HTT-40 betters PC-7 by good margin on many parameters. This is mainly due to more powerful engine which was selected keeping weaponization in mind.
- Within first 50 flights, 6 major PSQR requirements are already achieved.
- Preliminary Design resulted in 4705 drawings. The engine had to be changed midway from PW to Honeywell (PW excused itself from the program for some reasons). This resulted in rework on engine part with 2000 modified drawings.
- Close 300 electrical drawings were generated.
- Close to 700 WT tests for initial configuration design. Learning from IJT experience, a mathematical model for the aircraft was developed early into the design cycle. Not that its very critical but absence of it might be an impediment.
- Early focus on Spin tests, starting from Aug 2015, learning from the IJT Sitara experience. The WT tests done in France show very promising results on spin characteristics.
- Weight reduction program has already commenced for HTT-40 to make more room for weaponisation.
- Digital Mock-up (DMU): Fully functional (systems' functionalities can be simulated) DMU was made which gave a very good picture of everything to all the concerned teams. Production team was involved right in the design phase, again resulting in shorter design cycle with less modification needed on the account of manufacturability. DMU also expedited assembly process since position of all parts was known ahead of time.
- CEMILAC had full access to the DMU..!!
- CAT-1 crash on IJT-36 due to FCS circuit issues, which was taken care of in HTT-40 already.
- Since IAF was not onboard for HTT-40, they never issued any RFA (Request for Action) for maintainability of HTT-40. HAL took RFAs issued for IJT-36 and LCA and incorporated them in HTT-40, to remain ahead in the game.
- Almost 70% of LRUs in HTT-40 are borrowed from IJT-36, LCA and even from Dornier and ALH. (due to time and cost contraints). This not only reduced development time but also System testing time.
- The prototypes were built using production level jigs (Would result in quick productionization of HTT-40)
- Huge participation from Local MSMEs. The target set by the RM of 60% involvement of privet players was met with ease.
- Total of 4900 parts. Most critical/special components were made in HAL. Close to 3000 parts from private companies. Divided into categories and about 150 critical parts were sent to CEMILAC for clearances. Rest of the parts were cleared by HAL itself with the delegated authority from CEMILAC.
- Wiring looms (total 180 nos) done on the bench right from prototype manufacturing, reducing wiring time from 2-3 months to 2 days.
- Wings were outsourced to Taneja Aerospace, but the company went into financial troubles. HAL had to take over the wing production, setting back the program by 2months. This is the reason there was no STS specimen in time. CEMILAC allowed prototype wings to be used for testing upto 100%. Later new set of wings were available for ultimate load testing of 150%.
- Total 65 EGR (Engine Ground Run) before the first flight, out of which 40 EGR were done ny HAL on its own. Instead of 3days per EGR, HAL could do 8 EGR per day to finish all EGR tesing in 15 days. This followed by the LSTT, HSTT, FRRB etc followed by the first flight.
- Interesting information - HAL always blamed to have too much FoS on wing design (upto 200%). Ideally wing should break at 151%. For HTT-40, wing broke at 161% in the ultimate testing. This shows the level of optimization. HAL previously has had ultimate failures at >190% for similar wing structures, indicating over design, resulting in overweight.
- By allowing restricted testing for the first flight clearance, CEMILAC could cut down time by 1-1.5yrs.
- Fuel system certification using jigs take 1yr typically. But CEMILAC took different approach for HTT-40 based on analysis and simulation, cutting down a significant time of fuel system certification.
***Flight Testing
- Decision on Flight test points. Test point repository was made.
- Total 490 test points identified. 44 flights taken place and 3 design modification done already, resulting from the flight tests - Rudder design was modified, Fuel tanks were pressurised and Aileron balance tabs were introduced.
This shows that when SDRE Evil Yindoos come together, they can prepare and execute their dark, nasty plans very well.
