LCH and other Helicopters Discussion Thread

Kartik · Post by **Kartik** » 07 Apr 2010 00:51

Rahul M wrote:kartik, DIRCM too.

p.s. Gp Capt Hari Nair was one of the crew on the LCH flight.

Yeah, DIRCM too. missed out on that. Gives it protection against IR seekers on MANPADS. Very critical feature.

yeah I noticed that he was the gunner..Gpt. Cpt Unni Krishnan in the pilot's seat. It was mentioned in the first report before we even saw the pics.

Rahul M · Post by **Rahul M** » 07 Apr 2010 00:59

kartik, re: g-force, 10m/s. that was from ajai shukla's earlier report. but he might have missed another s in the unit, in which case this would be 1 g assuming rest of figure is correct. what are normal figures for g tolerances of helo landing gear ?

btw, an interesting comment in aroor's blog, that rings genuine IMO.

Anonymous said...

Gentlemen-
A few clarifications on some of the comments posted here-
- The turreted gun is not a dummy,its very much real.
- The cockpit glass area will be reduced after flight testing - to the optimal minimal.
- All of you guys have got the weights wrong - the helicopter is capable of higher all-up-weight ! {very valid point, shakti gives 20% higher power, there should be a commensurate increase in max T/O wt from the 5.5 t for the old TM333. HAL hasn't changed one comma in those specs fro LCH, so we don't have the complete picture yet. same should be true for shakti powered WSI versions.}
- The landing gear is crashworthy - which mean it has been tested to absorb high crash loads and is very much sturdy.
- The stub wings already are designed to carry substantial weaponload its been designed not to interfere with the rotor during hover, which is important for high altitude operations.

nitpick : Gp Capt Unni Pillai, not krishnan.

Jayram · Post by **Jayram** » 07 Apr 2010 01:17

Jayram wrote:Noticed something from the earlier mockups from AI's of the past .
The length of the stubby wing has been definately reduced. It may even support just one hard point now compared to the two in the mockps .

Its wrong to quote my own post but I think I was wrong on the hardpoints I think LCH can support 2 - in the LCH picture seen here http://static.social.ndtv.com/files/wal ... 951349.jpg
at higher resolution we can see support for two hard points one at the extreme end and one at the middle..
Interestingly the exhaust from the engine has an exposed copper tubing for better heat transfer (as anyone who has cooked in copper vessels can attest) - showing the detail that HAL went to minimize IR signature. Copper btw is almost twice as efficient a heat conductor as Aluminum which is obvously lighter.

Anujan · Post by **Anujan** » 07 Apr 2010 01:40

Kartik wrote:Yeah, DIRCM too. missed out on that. Gives it protection against IR seekers on MANPADS. Very critical feature.

yeah I noticed that he was the gunner..Gpt. Cpt Unni Krishnan in the pilot's seat. It was mentioned in the first report before we even saw the pics.

IIRC in the LCH that flew that gunner seat had redundant flight controls. The weapons controls will be integrated starting with the next prototype.

Aditya G · Post by **Aditya G** » 07 Apr 2010 02:17

A bit OT:

Apparently the Dhruv used in Naxal ops is a wheeled version. Must be ex-Navy prototype?

Anujan · Post by **Anujan** » 08 Apr 2010 23:30

Aditya G wrote:A bit OT:

Apparently the Dhruv used in Naxal ops is a wheeled version. Must be ex-Navy prototype?

It belongs to the BSF

Kartik · Post by **Kartik** » 09 Apr 2010 05:13

Rahul M wrote:kartik, re: g-force, 10m/s. that was from ajai shukla's earlier report. but he might have missed another s in the unit, in which case this would be 1 g assuming rest of figure is correct. what are normal figures for g tolerances of helo landing gear ?

Ajai Shukla was just writing something. Its not accurate and I've had this feeling about some of his earlier reports as well (such as the figures he reported for the Kaveri thrust, the Tejas empty weight, etc.). When queried further he just clams up. From the DRDO Tech Focus April 2010 issue.

Helicopter should be able to withstand the loads arising due to crash conditions of 35 g forward, 12 g rearward, 25 g downward, 8 g upward, and 12 g
sideward.

VinayG · Post by **VinayG** » 09 Apr 2010 05:36

Jayram wrote:
Jayram wrote:Noticed something from the earlier mockups from AI's of the past .
The length of the stubby wing has been definately reduced. It may even support just one hard point now compared to the two in the mockps .
Its wrong to quote my own post but I think I was wrong on the hardpoints I think LCH can support 2 - in the LCH picture seen here http://static.social.ndtv.com/files/wal ... 951349.jpg
at higher resolution we can see support for two hard points one at the extreme end and one at the middle..
Interestingly the exhaust from the engine has an exposed copper tubing for better heat transfer (as anyone who has cooked in copper vessels can attest) - showing the detail that HAL went to minimize IR signature. Copper btw is almost twice as efficient a heat conductor as Aluminum which is obvously lighter.

i might be ignorant but for me it looks like a dud structure not the genuine type of stub wings i need to wait till i see this bad boy flies with weapons

VinayG · Post by **VinayG** » 09 Apr 2010 05:40

at the end of the day it is a prototype we all need to wait till we get to see the production variant

Rahul M · Post by **Rahul M** » 09 Apr 2010 05:47

thanks a lot for hunting out that nugget kartik, sounds impressive to me.

jaladipc · Post by **jaladipc** » 09 Apr 2010 06:43

They say that the IR supression was given much priority.The intake inlet(variable nozzle) diverts as much air to cool the exhaust before hitting outside air.

Gagan · Post by **Gagan** » 09 Apr 2010 07:42

On the subject of IR supression for Attack helicopters, this is what the commanche had planned for engine exhaust dispersal.

nishu · Post by **nishu** » 11 Apr 2010 16:12

guys i think there are 2 lch prototypes . check out this image there is another lch behind the fire engine you can cleary see its tail http://www.bharat-rakshak.com/IAF/Image ... 1.jpg.html

Gagan · Post by **Gagan** » 11 Apr 2010 16:37

That is not an LCH, that is a WSI Dhruv.

Jingoes and gurujis have been over that photo with a fine tooth comb many moons ago.

Avinandan · Post by **Avinandan** » 11 Apr 2010 20:44

I have a small nitpick

Why the rear landing gear is so long ?
Almost all the modern attack helis have just a wheel at the end of its tail.

ArmenT · Post by **ArmenT** » 11 Apr 2010 22:15

^^^^
Ever thought that the picture you're seeing is a Tech Demonstrator and not the final production model. Tech demonstrators typically borrow some parts from other projects. Heck, the first F-117 prototype had borrowed parts from other aircraft, including landing gear taken from an A-10. Ugly as heck, but the purpose of the first prototype was to validate the flying characteristics and it did its job well.

If they decide to change the landing gear, that could happen later on.

negi · Post by **negi** » 11 Apr 2010 23:45

Avinandan wrote:I have a small nitpick
Why the rear landing gear is so long ?
Almost all the modern attack helis have just a wheel at the end of its tail.

When you say long what other helis are you comparing it with Apache/Eurocopter tiger or even Mi-28 havoc ?

If you would observe the tail boom of each of the above three choppers is at same level as the fuselage in the front so it has a relatively lower ground clearance when compared to the tail boom of LCH , this should explain the need for longer strut which contributes to the size of the landing gear .

Longer landing gear struts imo are in line with high crash worthiness requirements for the LCH as mentioned by Kartik in his post .

rohitvats · Post by **rohitvats** » 12 Apr 2010 17:03

LCH in air...repeat, LCH in air...doing rounds around the HAL Airport and adjoining areas....

man, am I happy or what? Delirious to be precise...that think looks menancing in the black color and especially, with the overcast conditions here in Bangalore...hunter on the prowl...

and doesn't look big in the side profile...was looking especailly at the cockpit...difficult to figure out..forget all the theories about getting it with AK or any K...and mind you, I've seen the Hinds during flight and IMO, at the altitude this bird was flying, the Hind will look huge....

Venu · Post by **Venu** » 12 Apr 2010 17:46

rohitvats wrote:LCH in air...repeat, LCH in air...doing rounds around the HAL Airport and adjoining areas....

Copy that. Time to test your mobile cams resolution and zoom.

sunny_s · Post by **sunny_s** » 12 Apr 2010 17:49

veenu ji and rohit ji get us a pic of our tiger

any pic would be appreciated and thanked from the core..i really think sometimes having your office near HAL IS FUN

Bala Vignesh · Post by **Bala Vignesh** » 12 Apr 2010 19:03

Rohitji... Could you ping your emailid to djvignesh@gmail.com,please..?

rohitvats · Post by **rohitvats** » 12 Apr 2010 22:14

Bala Vignesh wrote:Rohitji... Could you ping your emailid to djvignesh@gmail.com,please..?

You've got mail...

jaladipc · Post by **jaladipc** » 12 Apr 2010 22:27

Avinandan wrote:I have a small nitpick
Why the rear landing gear is so long ?
Almost all the modern attack helis have just a wheel at the end of its tail.

IT was meant for two things.One is crash worthy aspect and other is center of gravity aspect.

though the location being there is not confirmed that the production ones will go with the same as well.SO possible chances of relocation cant be overlooked.

anand_sankar · Post by **anand_sankar** » 13 Apr 2010 16:36

FLIGHT ALERT!!!!!!!!!!!! LCH flies in stormy skies!

The LCH just took off from HAL's Helicopter Division about fifteen mins ago.

Was on my terrace enjoying the strong wind and light rain, when suddenly a Dhruv popped up. I was wondering why they are flying in such gusty conditions and then another chopper popped up. I took a few seconds for my eyes and brain to register what was happening, when the tiger flashed brilliantly thanks to sharp low sunlight from the west. My jaw dropped, I was paralysed! Before I could run downstairs and get the SLR with long lens, it was gone.

Guys let me know if the bird is gonna fly from Helicopter Division permanently. I am in-between jobs with lots of time, I can camp the whole day on terrace for this.

Gawd, it was gorgeous sight seeing the bird rise up into the grey overcast! They must be pretty sure of its handling to fly in this weather.

anand_sankar · Post by **anand_sankar** » 13 Apr 2010 17:15

Guess the flight landed at the HAL Airport, no sign of them coming back to Helicopter Division yet.

But must say, what a PR opportunity for HAL, the Dhruv being the chase aircraft for the LCH!

Some observations from the brief sighting:

1) The LCH is quieter than the Dhruv. Heard the Dhruv, but the LCH seems at least 30-40% quieter.

2) What a menacing front profile!

3) Phenomenal T/W ratio? The LCH sliced through a headwind while the Dhruv looked laboured. But this could also be due to the Dhruv waiting for the LCH to catch up and then chase it.

4) The frontal aspect is very narrow and sleek, while side-on the profile is quite obvious

5) The tail landing gear is oversized in appearance and can be seen more obviously than the main gear

Philip · Post by **Philip** » 13 Apr 2010 19:20

There were some attack helo designs in the past with upward facing exhausts,the opposite of the Commanche,where the heat would be further dispersed by the rotor blades and as the nozzles were facing upward,less susceptible to MANPAD IR seekers,since several attacks are from the rear where the engine nozzle signatures are greatest.

shiv · Post by **shiv** » 15 Apr 2010 19:32

Saw the LCH flying over the golf course for an hour. I played like an idiot, but seeing the LCH made up somewhat..

My cellphone camera is too stupid to actually catch the LCH and its accompanying Dhruv. It takes 15 seconds to "boot up" into camera mode so..

Bala Vignesh · Post by **Bala Vignesh** » 15 Apr 2010 19:57

Waah... had to shift from my office at manipal hospital....

Gonna miss all the action there...

chaanakya · Post by **chaanakya** » 15 Apr 2010 21:25

shiv wrote:Saw the LCH flying over the golf course for an hour. I played like an idiot, but seeing the LCH made up somewhat..

My cellphone camera is too stupid to actually catch the LCH and its accompanying Dhruv. It takes 15 seconds to "boot up" into camera mode so..

Need to "Boot out " Your cellphone.

Singha · Post by **Singha** » 16 Apr 2010 09:42

my observation of usha ceiling fan is near the center the airflow is not huge.
there is an area near the circumference of the circle where airflow is high.
so a upward pointing exhaust near the axis of the rotor might not encounter
a heavy airflow to dissipate it strongly....maybe thats why commanche went for the exhaust-in-tail-boom design, probably mixing it with bleed air from
the turboshaft inlets to always keep a strong flow ongoing. they could even
run a set of liquid nitrogen filled tubes as a heat sink there to flow the air
over and cool it to room temp before emitting

too bad it was too costly and cancelled -

isubodh · Post by **isubodh** » 16 Apr 2010 10:58

in upward facing exhausts how they prevent water from getting-in in case of rain or something similar ? a) while blades moving b) while stationary

sugriva · Post by **sugriva** » 16 Apr 2010 11:03

^^^ when stationary they use an umbrella.

Singha · Post by **Singha** » 16 Apr 2010 11:05

to sweep the tactical battle area clear of enemy attack and transport helis,
one needs a platform
- RCS stealthy esp when painted from above by roving enemy fighters
- long loiter time
- low noise and IR signature
- atleast 6 medium range AAMs(20km)
- all aspect medium range radar(20km) using skin panels/pods etc
- moderate transit speed
- rough field capability
- ability to log into the 'network' to get the tactical picture
- easy to operate and maintain
- cheap enough to deploy in solid numbers
- in A2G version, replace AAM with ATGM and add a thermal pod,
use a radar-lite for self defence evasion only

I believe this is one area where our first UCAV efforts could be directed
rather than a more ambitious deep-strike platform of the X-xx variety
shown by boeing/lockheed.

Anujan · Post by **Anujan** » 16 Apr 2010 11:15

isubodh wrote:in upward facing exhausts how they prevent water from getting-in in case of rain or something similar ? a) while blades moving b) while stationary

Two things. First the exhaust has such a high pressure and the internals of a gas turbine so hot that it doesnt matter. For Jet engines, rain ingestion is something that engines are certified for (they should be able to ingest some amount of water and still work)

Avinandan · Post by **Avinandan** » 16 Apr 2010 13:36

OT for LOH

Link:--
http://www.globalsecurity.org/military/ ... ia/loh.htm

The Ministry of Defence (MoD) recognised HAL’s growing competence in helicopter design by nominating it to design and manufacture half of the 384 light observation helicopters (LOHs) required by India’s military. HAL was given until 2017 to produce 187 LOHs. Meanwhile, the military’s immediate needs would be met by buying 197 LOHs from the international market. The MoD imposed a strict timeline on HAL, including — for the first time ever — a penalty for delay. If HAL overshoots the 2017 deadline, the MoD will procure more helicopters from the global manufacturer selected to supply LOHs; HAL’s order will correspondingly reduce. HAL is confident it will produce the LOH two years ahead of the MoD deadline, by 2015. HAL said in mid-2008 that with the LCH design complete, its in-house design center, called the Rotary Wing R&D Centre (RWRDC), was going full steam ahead on the LOH design.

So anybody knows about HAL LOH status currently ?

TIA.

vivekmehta · Post by **vivekmehta** » 16 Apr 2010 14:13

Avinandan wrote:OT for LOH

Link:--
http://www.globalsecurity.org/military/ ... ia/loh.htm
The Ministry of Defence (MoD) recognised HAL’s growing competence in helicopter design by nominating it to design and manufacture half of the 384 light observation helicopters (LOHs) required by India’s military. HAL was given until 2017 to produce 187 LOHs. Meanwhile, the military’s immediate needs would be met by buying 197 LOHs from the international market. The MoD imposed a strict timeline on HAL, including — for the first time ever — a penalty for delay. If HAL overshoots the 2017 deadline, the MoD will procure more helicopters from the global manufacturer selected to supply LOHs; HAL’s order will correspondingly reduce. HAL is confident it will produce the LOH two years ahead of the MoD deadline, by 2015. HAL said in mid-2008 that with the LCH design complete, its in-house design center, called the Rotary Wing R&D Centre (RWRDC), was going full steam ahead on the LOH design.

if this is true , then its a good strategy by MOD to encourage localization , they should copy this model to other projects also like LCA MK2 , Arjun MK 2.

Katare · Post by **Katare** » 16 Apr 2010 22:53

LCH timeline from Defense standing committee report.....

Light Combat Helicopter (LCH)
LCH is proposed to be developed to meet the need of combat helicopter for IAF. LCH will have maximum possible commonality with ALH and will incorporate number of stealth features and crash-worthy landing gear for better survivability.
Sanction for the development project was accorded in Oct 06 at cost of Rs.376.67 Cr and a timeframe of 50 months (Oct 2010) for achieving Initial Operation Clearance.
Following development activities have been completed;
o Overall configuration studies and Optimization of overall geometry
o Definition of common parts
o Landing gear – preliminary design
o Preliminary layouts of Armour panel, Pilot & co-pilot layout, Armament boom, pylons and various weapon integration configurations
o Wind tunnel test for fuselage configuration definition
Further design work is progressing as per schedule and the project is expected to be completed within the specified timeframe.

Kartik · Post by **Kartik** » 16 Apr 2010 23:03

sugriva wrote:^^^ when stationary they use an umbrella.

aside from the smart alec reply, the fact is that it was a good question that some designer would have had to face.

In aircraft skin panels, they have something called a "drain hole", with a scupper that basically works by using gravity to pull moisture out from the skin panels inner mould line sides. I'm guessing they'd have had some drain holes as well to prevent water ingestion due to up-turned exhausts.

Gagan · Post by **Gagan** » 17 Apr 2010 09:14

This is on the comanche engine exhaust system: From FAS

Infrared (IR) suppression. The Comanche only radiates 25% of the engine heat of current helicopters, a critical survivability design concern in a low-flying tactical scout helicopter. The Comanche is the first helicopter in which the infrared (IR) suppression system is integrated into the airframe. This innovative Sikorsky design feature provides IR suppressors that are built into the tail-boom, providing ample length for complete and efficient mixing of engine exhaust and cooling air flowing through inlets above the tail. The mixed exhaust is discharged through slots built into an inverted shelf on the sides of the tail-boom. The gases are cooled so thoroughly that a heat-seeking missile cannot find and lock-on to the Comanche.

Infact the entire range of innovations are worth a read: FAS on RAH-66 Comanche

Youtube video: http://www.youtube.com/watch?v=DBE8RHEXUEk

Gagan · Post by **Gagan** » 17 Apr 2010 11:20

More on the Comanche and similarity in the main rotor with the LCH

Comanche Main rotor: Designed to produce very less noise.

LCH main rotor:

__________________________________________________________________________________________
more on the Comanche engine exhaust system

The mission data card: The pilots just insert this card into the chopper and the mission details are uploaded:

Also the chopper communicates seamlessly with ground forces, AWACS and any friendly platform that it encounters. It appears that there is a powerful antenna above the main rotor in the housing there.

Another link about the Comanche: Link