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Indian Military Helicopters

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Re: Indian Military Helicopters

Postby negi » 07 Oct 2017 12:27

Arunachal ops are turning out to be very very challenging we lost a Su-30 few months ago there ; in mountains choppers have no margin for error as one could be making rapid transitions to and from ground effect zones .

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Re: Indian Military Helicopters

Postby Manish_P » 07 Oct 2017 12:46

Even at peacetime


Shiv sir, beg to slightly differ from you (and perhaps 99.9% of others on BRF) on this.

IMHO we are not at peacetime. Never have been. Ever since our independence we have been forced into an existential war. One which will end only when either our enemy (the physical and the ideology) or we cease to exist.

Peacetime is a luxury that countries like New Zealand or Denmark or Switzerland enjoy as a normalcy.

It's just that 99.9% of our humongous population are able to go on peacefully with their routine lives due to the 0.1% of our finest, who fight the war everyday, against the enemy and the elements.

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Re: Indian Military Helicopters

Postby JTull » 07 Oct 2017 13:09

negi wrote:Arunachal ops are turning out to be very very challenging we lost a Su-30 few months ago there ; in mountains choppers have no margin for error as one could be making rapid transitions to and from ground effect zones .


Seems increased focus on the NE due to the belligerent neighbour has meant expanding operations and capabilities in the region. These accidents are happening perhaps due to a combination of inadequate institutional experience, SOPs and training for that specific environment.

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Re: Indian Military Helicopters

Postby deejay » 07 Oct 2017 13:23

JTull wrote:
negi wrote:Arunachal ops are turning out to be very very challenging we lost a Su-30 few months ago there ; in mountains choppers have no margin for error as one could be making rapid transitions to and from ground effect zones .


Seems increased focus on the NE due to the belligerent neighbour has meant expanding operations and capabilities in the region. These accidents are happening perhaps due to a combination of inadequate institutional experience, SOPs and training for that specific environment.


Tawang Ops and Para drop has been going on longer than Siachen. There is no lack of institutional knowledge or SOPs. There was a Wg Cdr on board, a Sqn Ldr which means at least 3000 hrs flg between them. The load master (Flt Gunner) was a Master Warrant Officer. He would have at least twice the experience of the pilots alone.

The bolded part in the quote above is a very definitive opinion without adequate information. Let us wait before passing judgments. Para getting entangled in the tail rotor is always a possibility and yet a freak occurrence.

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Re: Indian Military Helicopters

Postby deejay » 07 Oct 2017 13:40

Indranil wrote:Thanks deejay for the explanation. Did not think of the extra payload angle. What parachutes are used for this. Version of the PTA-M?
Also, the typical extraction method through drogue chutes can't be executed because of the tail rotor. How is the payload extracted and the parachute deployed for safe separation.


I am not sure what make is the parachute. In fact, I do not remember the type and make from even my time so hard to tell the ones in use now. Will see if I get this info.

The skids/ pallets are hard wood boards on which the load is tied. The para is attached on top of the load for it to trail and deploy behind the load as it falls with gravity.

About 30 seconds prior to drop the Captain cautions the crew for drop. The aircraft is in straight and level flight with IAS 120 kmph. The aircraft has a slight pitch up attitude.

The load master then instructs the load despatchers (in this case the 02 army jawans) to prepare the load, The despatchers untie the load restraining ropes and physically release (Requires some strength) the pallets which slide out from the back as the aircraft is tilted nose up. The pallets / skids slide out dragging the para behind them. Normally they are well clear of the tail rotor.

In this image from TSarkar ji on the Flight Safety thread you can clearly see the load and paras clearing the helicopter.

Image

If you look carefully there is a tripod like projection downwards below the tail boom stabilizer just ahead of the tail rotor. This is the tail guard. It serves in protecting the tail rotor from striking the ground during extreme nose up landings and is also meant to come in between a para or loose material flying in to the tail rotor. This is a mandatory fitment for Air Maintenance with Mi 17 versions and is part of SOP.

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Re: Indian Military Helicopters

Postby chola » 07 Oct 2017 14:00

Manish_P wrote:
Even at peacetime


Shiv sir, beg to slightly differ from you (and perhaps 99.9% of others on BRF) on this.

IMHO we are not at peacetime. Never have been. Ever since our independence we have been forced into an existential war. One which will end only when either our enemy (the physical and the ideology) or we cease to exist.

Peacetime is a luxury that countries like New Zealand or Denmark or Switzerland enjoy as a normalcy.

It's just that 99.9% of our humongous population are able to go on peacefully with their routine lives due to the 0.1% of our finest, who fight the war everyday, against the enemy and the elements.


You are giving TSP way too much credit. No, we are not in an existential war with the Bakis. They are disgusting biting insects but they never had the ability threaten the existence of India.

If we had entered into an all-out war in 1947, 1965 or 1971 where 99% of the population were at war then Pakistan would have been snuffed out of existence. The converse was never true. At the very worst it would have meant the loss of J&K nothing more.

People please, stop this “woe is us” type of thinking. Pakistan is goddam failed state with fourth of our population. It does not and cannot threaten our existence any more than a dog does a lion.

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Re: Indian Military Helicopters

Postby Manish_P » 07 Oct 2017 16:59

I am not. What i am saying is that we are engaged in an ongoing war, and are not at peace.

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Re: Indian Military Helicopters

Postby Indranil » 07 Oct 2017 22:16

Thanks Deejay,

There seems to be more clearance than I thought in a typical drop. I can think of only two ways that the tail rotor and the parachute could have come together:

1. The heli hit an air pocket at the moment the payload left the aircraft and lost height simultaneously. This is unlikely, but possible.
2. The payload may have got stuck (even momentarily) on its way out, and the parachute bellowed out like a drogue parachute.


==============================================
1. I really hope that the controlled aerial delivery system (CADS) developed by ADRDE come online so that deliveries can be taken care of from fixed wing aircrafts.

2. HAL has made so many modifications to the Do-228. Wonder if it could fit it with a rear ramp.

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Re: Indian Military Helicopters

Postby deejay » 07 Oct 2017 22:23

^^^ Indranil, where the accident happened - that particular DZ is a tight on space even for a helicopter - no transporter is doing a drop there. Almost immediately after the drop one has to initiate a tight turn.

From what I have heard both options 1 and 2 could have occurred together and some other possibilities but as always this is conjecture and the COI will establish the cause.

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Re: Indian Military Helicopters

Postby Indranil » 07 Oct 2017 23:06

Controlled Aerial Delivery System (CADS) should enable the drops from higher heights. Which should enable fixed wings.

This system delivers the 500 kg payload material(using Ram Air Parachute duly controlled through its control lanyards) to the designated area within 100 meter CEP using GPS based Para flight control computer. The CADS 500 kg has also undergone trials at High Altitude Area like Leh, Yumthang, Sikkim and the technology has been demonstrated to the users successfully.

The laboratory is presently working on the similar system for 1 Ton payload capability and intends to extend it to 3-4 Ton payload.


Controlled Aerial Delivery System (CADS) issued for precise delivery of payload to a pre-designated target location. This is achieved by using a Ram Air Parachute along with onboard microcontroller, GPS and electronic instrumentation. The system is capable of delivering a payload of 80 to 500 kg from a max. height of 9500 m covering a stand off distance of 2.5 times the drop altitude with aCEP of 100m (approx).


Image

Image

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Re: Indian Military Helicopters

Postby shiv » 08 Oct 2017 08:07

JTull wrote:Seems increased focus on the NE due to the belligerent neighbour has meant expanding operations and capabilities in the region. These accidents are happening perhaps due to a combination of inadequate institutional experience, SOPs and training for that specific environment.

If you spend hours on Google earth as I have done - looking at images in the NE from 2010 and later the number of helipads you see are definitely not a recent phenomenon. Those helipads have not appeared overnight. Supplies are by helo to a lot of those areas and I think media attention and our attention has become focused on the NE after Doklam. This is one of the points that causes me some angst - it is the general ignorance of even the more "aware and educated" public about the geography and conditions in the North east. That is a blind spot for us and perhaps we have to thank China for its recent chootiyapa so more people become aware of the fact that life exists east of Bangladesh

ON BRF and Twitter I find people blaming every accident on Chinese cyber ops or special weapons covered over by the semantic claim that "We are at war". These fantasises only help us to remain ignorant of the geography and weather. To continue to rant - we probably have hundreds of BRFites who will tell us weather conditions across North American airports - but I bet we have very very few who know that commercial flights out of many mountain airfields in the north eat and north do not allow any landing or takeoff in the afternoons and evenings because the air temperatures are higher, air density lower and the weather "closes in" with clouds and rain. If we had a general understanding of what our pilots face we would not be talking shit about Chinese cyber war. Fits in perfectly with the adage "What the mind does not know, the eye does not see"

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Re: Indian Military Helicopters

Postby joygoswami » 08 Oct 2017 08:31

Cross posting from Military Flight Safety thread. Super Puma crash investigation Norway. MUST SEE.



On 29 April 2016, a CHC Helikopter Service Eurocopter EC225 Super Puma helicopter, carrying oil workers from the Gullfaks B platform in the North Sea, crashed near Turøy, a Norwegian coastal island 36 kilometres (22 mi) from the city of Bergen. Several witnesses reported initially seeing nothing untoward with the helicopter flying steadily, before the sound suddenly changed and it started to sway. A moment later its main rotor assembly detached from the aircraft and the fuselage plummeted to the ground and exploded into flames. All 13 crew and passengers died in the crash.

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Re: Indian Military Helicopters

Postby negi » 08 Oct 2017 12:51

CEP of 100 meter is huge for the terrain in Arunachal ; a very small DZ would mean using fixed wings is ruled out as they are limited by their stall speed so choppers are the only way to deliver stuff with pin point accuracy . Using sling type mechanism for transporting heavy loads and then lowering them is also a no no as I believe that would require the chopper to hover over the target for a long duration and risk being shot down by the enemy .

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Re: Indian Military Helicopters

Postby deejay » 08 Oct 2017 13:05

negi wrote:CEP of 100 meter is huge for the terrain in Arunachal ; a very small DZ would mean using fixed wings is ruled out as they are limited by their stall speed so choppers are the only way to deliver stuff with pin point accuracy . Using sling type mechanism for transporting heavy loads and then lowering them is also a no no as I believe that would require the chopper to hover over the target for a long duration and risk being shot down by the enemy .


OGE hover with underslung load, severely limits load carrying capability with altitude.

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Re: Indian Military Helicopters

Postby JayS » 08 Oct 2017 13:18

deejay wrote:
JTull wrote:
Seems increased focus on the NE due to the belligerent neighbour has meant expanding operations and capabilities in the region. These accidents are happening perhaps due to a combination of inadequate institutional experience, SOPs and training for that specific environment.


Tawang Ops and Para drop has been going on longer than Siachen. There is no lack of institutional knowledge or SOPs. There was a Wg Cdr on board, a Sqn Ldr which means at least 3000 hrs flg between them. The load master (Flt Gunner) was a Master Warrant Officer. He would have at least twice the experience of the pilots alone.

The bolded part in the quote above is a very definitive opinion without adequate information. Let us wait before passing judgments. Para getting entangled in the tail rotor is always a possibility and yet a freak occurrence.


True. The bolded part is rather unfortunate comment. Shit happens despite the best professionals handling things with utmost care. But as they say statistics catches up after a while. While thousands of hours of safe operations do not show up anywhere such unfortunate accidents show up like sour spots. Doesnt mean always there is somethi g lacking somewhere. Such events, be it any field, cannot be avoided 100% despite the best of care taken by all. There is no need to question professionalism of IAF without any definite data to assert short comings. The court of enquiry will figure out what happened and lessons will be learnt.

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Re: Indian Military Helicopters

Postby Indranil » 09 Oct 2017 06:18

Deejay,

I know that I should wait for the COI, but can't help thinking about this. The parachutes that are used for these drops: Are they packed in a bag like those of the paratroopers?

It's a simple solution isn't it. The cargo can yank the parachute out of the bag only after safe separation. The western type parachute bags won't work, because the bag and the cord flay behind the aircraft. But, the Russian or even the ADRDE styled desi ones would.

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Re: Indian Military Helicopters

Postby Rakesh » 09 Oct 2017 06:43

Vikas & Vikas: The Heartbreaking Tale Of 2 IAF Pilots
https://www.livefistdefence.com/2017/10 ... ilots.html

Image

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Re: Indian Military Helicopters

Postby Rakesh » 09 Oct 2017 06:52

There are pictures floating on Twitter and on the internet of the fallen members of the IAF and the Indian Army in the helicopter crash. They are gruesome to see. Out of respect to them and to their families, I plead with you to not post them in BRF. Please. I realize this will cause some to go and out search for these images and I cannot stop you from doing that. But please, do not post them in BRF.

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Re: Indian Military Helicopters

Postby Indranil » 09 Oct 2017 07:33

THERE IS NO PLEASE INVOLVED. IT WILL BE AN IMMEDIATE BAN.

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Re: Indian Military Helicopters

Postby deejay » 09 Oct 2017 08:51

Indranil wrote:Deejay,

I know that I should wait for the COI, but can't help thinking about this. The parachutes that are used for these drops: Are they packed in a bag like those of the paratroopers?

It's a simple solution isn't it. The cargo can yank the parachute out of the bag only after safe separation. The western type parachute bags won't work, because the bag and the cord flay behind the aircraft. But, the Russian or even the ADRDE styled desi ones would.


Yes, if my memory serves me correctly, they are in bag - one time use only.

I am sure post COI completion there are going to be changes instituted. Air Maintenance is the single largest component of Mi 17 flying and probably for the entire helicopter fleet too.

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Re: Indian Military Helicopters

Postby shiv » 09 Oct 2017 10:08

Since the topic has come up and has been subjected to a one sided debate - I want to bring up a contentious topic. Please pardon me for stating plain forensic medical facts

When you burn a body incompletely the muscle protein gets "cooked" and it contracts making a burning body assume what is called as a "pugilists" attitude - looking like a crouched boxer. That aside only the surface may be burnt so the wet insides will be leaking fluid and trying to lift such a body might cause the carbonized outer layers to slip off like a glove making the body difficult to hold with one's hands. If such a body is found on a remote mountainside how do you actually carry it up?

If an accident occurs in a remote helipad that has its provisions delivered by helicopter, should helicopters pre-deliver body bags and keep them on station so that witnesses are not shocked? How many body bags must be stored at each helipad?

It is a nasty subject, but death, nasty as it is - is among us all the time and while we must treat the dead with respect - what is "respectful treatment" of a body on a remote mountainside where there is no shop to source appropriate materials? Helicopters deliver goods wrapped in cardboard and plastic. Dumping that in remote areas is pollution. Asking the army to clear that causes indignation because the armed forces are soldiers not safaiwalas. But when they use the available packing material - plastic and cardboard - to carry wet leaking oozing bodies everyone is up in arms. We want dignity. We want sanitization.

Actually the solution is simpler than it may seem. Do not publish photographs of our dead. (Terrorist photos allowed) Deal with the deceased with as much dignity as possible.

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Re: Indian Military Helicopters

Postby Philip » 09 Oct 2017 12:46

Media today mentioned some tail rotor problem.How did they find out so quickly? From the injured survivor?

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Re: Indian Military Helicopters

Postby Austin » 09 Oct 2017 13:55

Livefist had posted that the Kerosene can parachute got stuck in tail rotor during dropout , Quite possible if that is true then Pilot would have RT to the base

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Re: Indian Military Helicopters

Postby srin » 09 Oct 2017 17:42

Indranil wrote:
shiv wrote:As far as my theoretical knowledge goes, the helo pilot will change the cyclic to bank, but once the machine has banked to the required angle the cyclic must be set back to a "normal" (or whatever) setting or it will keep banking, and try to roll over.

It is not as simple on a heli. In saturation, the pilot does provide input to correct, but that the heli does not respond to those inputs.

Read more here.


Not really a reply, but someone had posted this site called https://kaypius.com on one the threads a while ago and I'd bookmarked it, and over the weekend I spent a fascinating hour reading up on all the ways a chopper tries to kill you. Here's one that covers the stall issues including cyclic saturation: http://kaypius.com/2017/10/05/pushing-the-rotors-envelope/

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Re: Indian Military Helicopters

Postby shiv » 09 Oct 2017 18:28

srin wrote:
Indranil wrote:It is not as simple on a heli. In saturation, the pilot does provide input to correct, but that the heli does not respond to those inputs.

Read more here.


Not really a reply, but someone had posted this site called https://kaypius.com on one the threads a while ago and I'd bookmarked it, and over the weekend I spent a fascinating hour reading up on all the ways a chopper tries to kill you. Here's one that covers the stall issues including cyclic saturation: http://kaypius.com/2017/10/05/pushing-the-rotors-envelope/

Byootiful. I wonder if Air Marshal Matheswaran has read this?

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Re: Indian Military Helicopters

Postby deejay » 09 Oct 2017 18:52

^^^There is a Ray Prowtee mentioned there. He is the God of rotordynamics. He is right till he says he is wrong. The understanding of rotordynamics is incomplete till you incorporate advancing blade, retreating blade and gyroscopic motion. One of the favourite question of Air Crew Examination Board was what happens when hovering close to a wall on the left?

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Re: Indian Military Helicopters

Postby shiv » 09 Oct 2017 19:01

deejay wrote: One of the favourite question of Air Crew Examination Board was what happens when hovering close to a wall on the left?

:eek: What happens?

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Re: Indian Military Helicopters

Postby deejay » 09 Oct 2017 19:08

I forgot the explanation and the physics but I believe the helicopter starts moving left and back unless controls are applied.

Basically, it is how the forces through interference of Air flow because of the wall change on the retreating blade side for a clockwise rotation and this change precesses by 90 degrees and acts on the helicopter.

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Re: Indian Military Helicopters

Postby vina » 09 Oct 2017 19:16

shiv wrote:
deejay wrote: One of the favourite question of Air Crew Examination Board was what happens when hovering close to a wall on the left?

:eek: What happens?

My guess, you crash into the wall, because of the suction effect that will be created by the air flowing faster between the helicopter and the wall compared to the other side due to Bernouli effect.

My guess is that the rotor has to be tilted right to counter that.

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Re: Indian Military Helicopters

Postby deejay » 09 Oct 2017 19:20

No while hovering you have to cater to recirculating air which the wall on the left interferes with thus reducing the benefits of ground cushion. Also the force on the retreating blade acts 90 degrees to where it is applied as it precesses

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Re: Indian Military Helicopters

Postby shiv » 09 Oct 2017 19:22

No disrespect meant: Understanding the carriage of mortal remains of Tawang chopper crash-AVM Manmohan Bahadur
Put yourself at that post in an army man’s uniform. The aircraft is on final approach, the aircrew checks dropping zone is clear and commences the drop. The jawans on the ground see the approaching helicopter, which swings to the left (if the reports of a problem in the tail rotor are correct), crashes and catches fire.

Those jawans, at that 14000 ft altitude post, would have sprinted/crawled to pull out their comrades from the burning wreckage— but alas, none came out alive, only their mortal remains. The jawans would have used whatever dignified material they had to encapsulate their comrades– because there are no body bags available at each post. A wireless message back to base would have activated the crash plan of an Air Force Station standing by for Search and Rescue (SAR) duties.

A Dhruv Advanced Light Helicopter was launched post-haste, especially since the first reports said that there were two survivors. The reality of the situation would have hit the aircrew of the SAR helicopter on landing— they did what was expected of them and that was to bring back to the Base Hospital at Guwahati, their comrades who were ‘embalmed’ by their army brethren.

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Re: Indian Military Helicopters

Postby shiv » 09 Oct 2017 19:38

vina wrote:
shiv wrote: :eek: What happens?

My guess, you crash into the wall, because of the suction effect that will be created by the air flowing faster between the helicopter and the wall compared to the other side due to Bernouli effect.

My guess is that the rotor has to be tilted right to counter that.

Helicopter rotors can't be tilted

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Re: Indian Military Helicopters

Postby Indranil » 09 Oct 2017 20:22

While hovering, there is no difference in the flow around the advancing or the retreating blade. The wall on the left affects the vortex ring on the left, amplifying it. This asymmetry pushes the heli to the left and back.

This same phenomenon brought the heli down in Abottabad, except there were walls on all sides of the compound. The amplified the vortex ring on all sides and the heli experienced a sudden loss of lift and crashed down.

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Re: Indian Military Helicopters

Postby Zynda » 09 Oct 2017 20:31

shiv wrote:
vina wrote:My guess, you crash into the wall, because of the suction effect that will be created by the air flowing faster between the helicopter and the wall compared to the other side due to Bernouli effect.

My guess is that the rotor has to be tilted right to counter that.

Helicopter rotors can't be tilted

Hakim saab, the rotor blades disc can be tilted and it is how a chopper can pitch up & down and also bank sideways thus achieving forward & sideways movements.

This image is from Brittanica Encyclopedia

Image

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Re: Indian Military Helicopters

Postby shiv » 09 Oct 2017 20:43

Zynda wrote:
shiv wrote:Helicopter rotors can't be tilted

Hakim saab, the rotor blades disc can be tilted and it is how a chopper can pitch up & down and also bank sideways thus achieving forward & sideways movements.

This image is from Brittanica Encyclopedia

Image

I have a problem with Encyclopedia Britannica's explanation. Tilting left and right (banking) are done by changing the cyclic (angle of attack of rotor blades on left and right). The same can be achieved for forward flight using cyclic front and back. AFAIK no tilting of rotors needed.

I have never heard of the extra (fiddly, more moving parts)) mechanism to tilt rotors - which would mean tilting the rotor hub - but I think I can be re-educated if that is true

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Re: Indian Military Helicopters

Postby deejay » 09 Oct 2017 21:00

Indranil you are right but the mechanism of how it works is a combination of forces acting as explained above broadly.

Shivji, individual blades can be tilted and taken together all the blades act together to tilt cyclically hence tilting the rotor disc.

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Re: Indian Military Helicopters

Postby Zynda » 09 Oct 2017 21:04

I found a few images on the net on how individual rotor blades tilt can be achieved.

Image

Image

Image

Image

Sorry for the multiple images...

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Re: Indian Military Helicopters

Postby sudeepj » 09 Oct 2017 21:12

You can see the rotors tilt in this clip.

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Re: Indian Military Helicopters

Postby shiv » 09 Oct 2017 21:26

deejay wrote:Shivji, individual blades can be tilted and taken together all the blades act together to tilt cyclically hence tilting the rotor disc.

A little semantic miscommunication here. Yes the rotor tilts but the helicopter tilts with the rotor.

Does the rotor tilt separately from the body of the helo - that is can the rotor disc tilt 1-2 degrees forward/back or sideways without the helicopter also tilting with it?

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Re: Indian Military Helicopters

Postby JayS » 09 Oct 2017 21:39

shiv wrote:
Zynda wrote:Hakim saab, the rotor blades disc can be tilted and it is how a chopper can pitch up & down and also bank sideways thus achieving forward & sideways movements.

This image is from Brittanica Encyclopedia

Image

I have a problem with Encyclopedia Britannica's explanation. Tilting left and right (banking) are done by changing the cyclic (angle of attack of rotor blades on left and right). The same can be achieved for forward flight using cyclic front and back. AFAIK no tilting of rotors needed.

I have never heard of the extra (fiddly, more moving parts)) mechanism to tilt rotors - which would mean tilting the rotor hub - but I think I can be re-educated if that is true


Changing only AoA will not tilt lift vector in required direction. You could roll or pitch using differential lift but moving sideways or back and forth is not possible that way. Think of it using Newton's third law.


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