LCH and other Helicopters Discussion Thread

[VijayN]

But taking aim at those hinges . Why? There are much bigger and more vulnerable areas of a helicopter.

Agreed, it was a amateurish suggestion at my end. Idea was to only to ask, if this perhaps was a weak spot. I stand corrected gents (KaranM/Marten/Indranil).

[kmkraoind]

Anantha Krishnan M ‏@writetake

#LCHTD3 Dedicating to all Hari fans [ Grp Capt Hari Nari (Retd) ] out there.

Anantha Krishnan M ‏@writetake
#LCHTD3 Dedicating to all Unni fans [ Wg Cdr Unni Pillai (Retd) ] our there.

[Sagar G]

credit -- original poster elsewhere.

Shri Kota garu is like APJ of Indian aeronautics.

[Aditya G]

LCH is also our first full spectrum stealth aircraft. Somehow this is not getting highlighted enough.

[srin]

One question on the LCH: is the pilot in the front seat or is it the gunner ?

[Mihir]

Would it had been an overkill to have retractable landing gears?

Why? Is there a single clear benefit to retractable landing gear other than low RCS?

One question on the LCH: is the pilot in the front seat or is it the gunner ?

The pilot is in the front seat.

[Raveen]

[quote="indranilroy
@Raveen
Why would they put a fairing if it is draggier than what they surround?[/quote]

Exactly my question

[Raveen]

Would it had been an overkill to have retractable landing gears?

What? Is there a single clear benefit to retractable landing gear other than low RCS?

Lower drag

[Indranil]

@Raveen
Why would they put a fairing if it is draggier than what they surround?

Exactly my question

Because it is not!

[Mihir]

What? Is there a single clear benefit to retractable landing gear other than low RCS?

Lower drag

Not a clear benefit at the speeds a helicopter is expected to operate. It could easily be offset by increased weight.

[Mihir]

Duplicate

[member_28840]

@indranil

thanks for the reply and the photos. interesting to hear the Dhruv is getting a ducted tail rotor.

[Raveen]

Exactly my question

Because it is not!

Doesn't meet the eye test - one strut versus a very boxy looking fairing...but if you say so.

[Raveen]

Lower drag

Not a clear benefit at the speeds a helicopter is expected to operate. It could easily be offset by increased weight.

Yet they made all these other changes to reduce drag and increase lift...and what speeds are you thinking this thing is going to operate at that allow sidestepping the rules of areo?

[Indranil]

I have no doubt that the fairing has a lower drag than the landing gear structure. I think the question is why is it not in the shape of an aerofoil. Well the bottom part cannot have a tapered edge because it has to have an opening for the play in the landing gear. I don't know why the top part does not have a tapered edge. By the way, I did not realize earlier that the fairing for the pylons have a tapered edge.


As I said earlier, the main landing gear has to absorb a lot of stress in the case of a crash. Making it retractable makes it highly complicated. HAL definitely knows how to make retractable grads for ALH.

[Mihir]

Yet they made all these other changes to reduce drag and increase lift

What changes have they made to reduce drag? I don't see anything significant apart from the tail gear fairing. And that fairing could have been put there for reasons other than reducing drag, for all we know. What I do know is that a big challenge facing the design team was weight reduction; I'm not sure how a heavier retractable landing gear helps with that.

As for increased lift, they obviously thought that it was worth the additional induced drag. Unless I am missing something.

...and what speeds are you thinking this thing is going to operate at that allow sidestepping the rules of areo?

Chaiwallah info onlee, but the LCH is not being designed to fly at supersonic or high subsonic speeds.

[Indranil]

There is another consideration in this weight vs drag equation. Though top speed in the plains may benefit from lower drag, hovering at higher altitudes suffers from the additional weight.

[member_28840]

Look at the shape of how the belly smoothly tapers into the tail and how it meets the horizontal stabilizer.
IIRC a rod shape will cause a vortex or at the least turbulent airflow. Therefore the fairing may have been introduced there to help with stability during maneuvers rather than a weight vs drag thing.

[JTull]

@indranilroy, is there a public source on fenestrons for Dhruv? How old is this news and what's the status?

[Shreeman]

some observations by an ignoramus: this helicopter (TD3) has been flying for a while before this public display. Even so, it is ridiculous to do this with packed stands of 1. people and 2. dhruvs.

That one fire truck will not do squat if something did go wrong and there isnt a safety cordon in sight. Dozens of HAL employees are wandering around clearly not needed for actual flight prep.

The show off ground level hover could have been done on a runway and still shown to employees live on a large screen better than they saw with their eyes. To do this with stands full of aircraft and people is clearly not intended to progress a test flight plan.

Why the HAL stands are so choked full of dhruvs of every description is another good question. There must be 20 helicopters sitting around. Is there a good reason why you would have an year's mnanufacturing sitting idle like this?

[Yagnasri]

LCH is also our first full spectrum stealth aircraft. Somehow this is not getting highlighted enough.

Is it? This is the first time I am reading about it.

[Neela]

some observations by an ignoramus: this helicopter (TD3) has been flying for a while before this public display. Even so, it is ridiculous to do this with packed stands of 1. people and 2. dhruvs.

That one fire truck will not do squat if something did go wrong and there isnt a safety cordon in sight. Dozens of HAL employees are wandering around clearly not needed for actual flight prep.

The show off ground level hover could have been done on a runway and still shown to employees live on a large screen better than they saw with their eyes. To do this with stands full of aircraft and people is clearly not intended to progress a test flight plan.

Why the HAL stands are so choked full of dhruvs of every description is another good question. There must be 20 helicopters sitting around. Is there a good reason why you would have an year's mnanufacturing sitting idle like this?

Is there a military safety thread where the above can go to.?

[Shreeman]

[vasu raya]

well, when coming in for landing the landing gear deployment on civilian airliners does feel like significant drag. Initially when the LCA Navy came out its landing gear looked too sturdy and perhaps they have been optimizing it for weight reduction. Even if we are talking about hot n high conditions for the LCH, while drag may not be an issue weight sure is.

Here is a video of a drop test, do we expect the dynamics to be very different for LCH after the Struts are removed?

[member_22539]

^Actually, are we even really sure that this is indeed the first tests of this kind on the LCH or is it just the first they are willing to publicize?

[Indranil]

This is the problem with internet ninjas. They seem to know everything. The other day, I read somewhere that they did not like the new colour scheme of TD3. In his words, if the bottom of TD3 would be coloured black, it would look like a taxi.

Anyways, the helicopters are parked on the left and the right of the central flight area (marked with solid white lines). Even within these solid lines there are dotted lines to guide the pilots in and out of their parking spots. If the helicopters are in their parking spots and the flying helicopter is in the center of the flying zone, then there is enough clearance between all helicopters, irrespective of their orientation. All flying is done within this central flight area. You will see that the after taking off the LCH moves to this central flying zone before carrying out the other tests. The same when coming in to land, It comes in on this strip and then moves sideways into its parking spot. The chase heli and the army heli also follow this procedure.



P.S. Do you see any HAL employees in the flight zone?!!

[Rahul M]

100 pages, time for a new thread.

[SaiK]

Is there line by line comparison between LCH and Harbin z-19 ?

[Indranil]

Thread locked. Question moved to current thread.