Thread by @vaimaniki

1. @HALHQBLR embarked upon development of two engines about 5yrs ago. #HTFE25 and #HTSE1200. HAL's philosophy has been to master the Aero engine design and Dev with a smaller engine and then to transition to Kaveri class engine. Plus HAL has own products which need these engines

2. So it made sense for HAL to go for one engine for its Helicopters and one for the Trainer class aircrafts that its making. And the development costs are within the limited autonomy that the Navaratna Status offers HAL. Thus the class of the two engines are chosen to suite

3. HAL's product line up, their technical capability and their financial autonomy. A very pragmatic strategy IMO.

#HTFE25 was the first one to kick start, perhaps because HAL wanted it to be ready for IJT Sitara. The Engine went from concept to Prototype in mere 3yrs.

4. Designed by young team from AERDC division of HAL, this performance is truly impressive. HAL leveraged 3D printing extensively to lower the entry barrier and leap frog, rather than going through sequential technology development cycle. I cannot think of any engine which even

5. close to the amount of 3D printed parts used in #HTFE25. An old blog post of mine where i had summarised a nice seminar by HAL engineer on #HTFE25 from AI-2015.

aquantumofmind.wordpress.com/2015/10/

6. #HTFE25 went on testbed for its first test run sometime in 2015. Fast forward to 2018, it had two prototypes which had completed 255 test runs as per HAL's last Annual Report. #AeroIndia2019 brings some updates on the engine. In the first step the core of the engine has been

7. tested and the performances was satisfactory as per HAL engineers in #AeroIndia2019. Now HAL is going ahead with full engine with LP system and perhaps an afterburner too. Hopefully we will see full system test of HTFE25 soon in near future.

8. #HTFE25 has 25kN thrust in dry mode which can be enhanced to 36-40kN once an afterburner is fitted in it. This makes it an ideal engine for ~5T class single engine aircrafts such as Trainers like IJT Sitara or ~9T class combat fighters such as Jaguar or some for a Business Jet

9. #HTFE25 feature -
- Modular construction
- wide chord fan blades
- High efficiency Compressor with VIGVs
- Advanced annular combustor
- Air cooled high efficiency turbines (3D printed HPT nozzle & rotor blades)
- Dual channel FADEC with Health Usage and Monitoring System HUMS

9. #HTFE25
Thrust = 25kN Dry, close to 40kN wet
SFC = 0.71 kg/kgf.hr
T/W ratio = 5.66
MFR = 43 kg/s
BPR = 0.5
OPR = 20.43
Max TET = 1450 K
Max Op alti = 11km
Relight envelop = 0-9 km
Weight ~ 450kg
Config = 3 LPC - 5 HPC - 1 HPT - 1 LPT

10. The second and perhaps more important for HAL is #HTSE1200 (Hindustan TurboShaft Engine). This engine is designed for 1200kW power at SL, specifically keeping in mind HAL's Helicopter lineup. It would replace Shakti engine currently powering ALH/LUH/LCH with 20% higher power.

11. As per one study, India has market for 6000 Helicopter engines. In fact IMO the potential is even higher. As HAL is only Helicopter maker, majority of these engines are going to be used at HAL's assembly lines. HAL has had troubled relationship with Scecma, whose engine power

12. All of HAL's helicopters as of today. If HAL can capture this huge Helicopter engine market, it will not only give HAL a long term sustainable business, but also save billions of USD for India in FE & bring about invaluable strategic autonomy in Helicopter sector at least.

13. #HTSE1200 is specifically designed so that it can power ~3.5T class Helis like LUH in single engine config or ~6.5T class helis in Twin engine config such as ALH/LCH. If there is need for higher power engine, a separate engine will be designed later accordingly, as per HAL.

14. #HTSE1200 has two high pressure ratio radial compressors, reverse flow effusion cooled combustor. single stage HPT for the gas generator and two stage power turbine. Interestingly the HPT contains Single Crystal blades with High temperature resistant coating, which enables it

15. to do away with requirement of cooled HPT blades, which must be helping it in achieving superior thermal efficiency. The SCB technology is clearly either a Shakti genes inherited or the SCB blades are being procured from French vendors, as HAL is unlikely to use the Russian

16. tech at its disposal, IMO (but i could be wrong of coarse). Just like its sibling, #HTSE1200 also features modular construction and FADEC with HUMS. The engine weighs 235 kg and can operate till 7km altitude.

17. From the last known status from HAL's AR 2017-18, #HTSE1200 prototype had completed total 150 test runs. I could not get any more update during #AeroIndia2019 on this engine. But hopefully the development is going on smoothly. Image of mockup of HTSE1200 from Aero India.

18. With a slow but steady progress, HAL is building engine design and development capability and should be in a position to offer alternative to GTRE in future. It then makes sense for GTRE to go ahead with a pvt manufacturing partner, so as to kickstart a pvt engine maker co.