Attack Helicopter Match-Ups: India vs. Pakistan

[illuminatidinesh]

The Hind were nicknamed as flying tanks.... This forum has already discussed that i think. There r instances that soviet pilots brought back the hellos after being hit by the stingers ...
Cobra do any one need to say? The name it self speaks for that.

 

[PLAextream]

The Hind were nicknamed as flying tanks.... This forum has already discussed that i think. There r instances that soviet pilots brought back the hellos after being hit by the stingers ...
Cobra do any one need to say? The name it self speaks for that.

ya your su30mki is also called" flying truck" .
as far as geting a hit by a sam & still able to land it is just a good luck of that pilot ,as the warhead of most of man pod sam specially stinger is capable enough to blow it apart(specially a copter).in iraq even a pvt cargo airline survived a SAM hit ,as the stinger damaged just one engine & luckly that palne han 4of them
The twin engine may help a bit in case a copter survive a direct hit but cobra lacks twin engine so if one engine goes out then its assured RIP .
& as far as hind is concerned i dont regard it as true attack helo,it is its mixed capability(weapons payload + utility) that made it popular with 3rd world countries.
cobra was never intended to be heavy weight attack choper (just like jf17 is not like j10)
later american's changed there war doctrine & replaced cobra with Apcahe.
Pakistan army relay on fighters for this role as copters are tempting targets for man pod SAM's.

any way india can now boast of having a flying tank(hind) & flying truck(su30) in its inventry as their orignal tanks like arjun are too heavy to move.

 

[illuminatidinesh]

ya your su30mki is also called" flying truck"

And U r the truck driver?
I thought the PLAF uses the same truck and tanks.........
The Hind got that name flying tanks U know Y? It has got bloody strong Armour.
And u better read what context i posted the message.
(SU 30 MKI = truck?? ---Off topic Come open a topic if u want to discuss about it)

 

[PLAextream]

And U r the truck driver?
I thought the PLAF uses the same truck and tanks.........
The Hind got that name flying tanks U know Y? It has got bloody strong Armour.
And u better read what context i posted the message.
(SU 30 MKI = truck?? ---Off topic Come open a topic if u want to discuss about it)

"BLOODY STRONG ARMOUR" ,dude if a missile make a direct hit on the engine or roter(or even tail stabilizer) then your bloody armour cant save your bloody pilots.
altough small arms fire could be sustained by hind.
lets go by facts:
stronger armour= more weight =require power full engine= more heat generated by engine =tempting target for HEAT SEEKING missiles.
& hinds dont have effective heat supressers .(as proved in afganistan 80% kill ratio made by stinger on hind).
Thats 1of the reasion your country's HAL trying a hell to reduce as much as weight from its on developement LAH.

 

[illuminatidinesh]

"BLOODY STRONG ARMOUR" ,dude if a missile make a direct hit on the engine or roter(or even tail stabilizer) then your bloody armour cant save your bloody pilots.
altough small arms fire could be sustained by hind.
lets go by facts:
stronger armour= more weight =require power full engine= more heat generated by engine =tempting target for HEAT SEEKING missiles.
& hinds dont have effective heat supressers .(as proved in afganistan 80% kill ratio made by stinger on hind).
Thats 1of the reasion your country's HAL trying a hell to reduce as much as weight from its on developement LAH.
PLAextream is offline Report Post Reply With Quote

The most kill as far as the Hind were concerned were not from stingers..... Check the facts. Instead they were made by attacks while on ground.
the soviets adapted very quickly.(engine armour were improved, they kept away from the range, extensively used flares(very minimal effect though).... so on)
Ur 80% kills were against the fixed wing aircraft's sir.
I like this kind of argument.

 

[illuminatidinesh]

Many bad experiences in Afghanistan (333 helicopters were lost in the ten years of Soviet occupation) prompted an upgrade pack for the Hind-D with various countermeasure modifications, including a radar-warning receiver (RWR), a chaff/flare dispenser and an infrared jammer (all this was fitted as standard to the Hind-E). Also, those hot exhausts were covered up with boxy filtration systems and the intakes with dust filters, making a Hind more difficult to hit with a heat-seeking missile like the Stinger.


Despite the overall failure of the Soviet campaign in Afghanistan and the Hind's high rate of attrition, the design seems to have fared reasonably. Mujahadin rebels were apparently terrified of the helicopter, calling it "Shaitan-Arba", or "Satan's Chariot". One source notes that pilots were often able to scare Mujahadin soldiers off by simply manoeuvring aggressively at them. Useful if they were out of ammunition. Pilots became highly proficient, performing manoeuvres and attacks that even the designers considered impossible. The poor suitability of the Mi-24 for night operations was not a deterrent to the pilots, who were trained to fly at night unassisted, using flares to illuminate suspicious targets.
During the 1980s an encounter between the two sides' helicopters graphically showed a serious flaw in the design of the Hind. An American AH-1 Huey Cobra met one while flying along the border between East and West Germany; the Hind had been ordered to intercept the Cobra and the pilots chased one another along the border for a while, the American pilot constantly pulling up sharply to force his faster opponent to overshoot. Apparently trying to duplicate this manoeuvre, the Russian pilot eventually pulled up too hard and stalled his aircraft. When attempting to pull out of the dive that followed, the main rotor blades of the Hind hit its tail boom and the helicopter crashed, killing everyone aboard.
I think the members will like this!!!!!!!!

 

[PLAextream]

of the topic, if we look at the physical structure of apache ,we see unlike cobra or hind's exaust it has a patient design module to cool the hot gases before leaving it's exaust .Even comanche model displayed a method to pass on the exaust gases of engine to tail section where it cooled before leaving out.These technique's reduce the heat signature of copter considerably.

i wonder if cobra's canopy could sustain Heavy machine gun fire (12mm) as they have huge visibility compared to hindered view of hind.

 

[gambit]

i dont know why the hell cobra has only 2 roter blades where basic physics tells that more the blades,more the lift ,less the noise(my theory),may be super cobra has 4roter blades?.

Nope, only increasing the number of blades do not increase lift or reduce he noise. Many factors, including wing design, dimensions, rpm etc decide the overall performance. You can achieve better results with two blades compared to four or more, by enhancing other parameters.

Increasing the numbler of rotor blades DO increase lift but could be cancelled out by not increasing the performance levels of other factors such as rpm or blade shaping.

Blades and Dissymetry of lift

The weight of a helicopter is divided evenly between the rotor blades on the main rotor system. If the helicopter weighs 5000 lbs and it has two blades, then each blade must be able to support 2500 lbs and so on. The more blades a helicopter has then the lower the weight that is carried on each blade compared to the same helicopter with less blades.

In order to understand why the two-blade configuration is so popular one must delve into the history of the helicopter itself. The above link has this paragraph...

All rotor systems are subject to Dissymetry of lift in forward flight. At a hover, the lift is equal across the entire rotor disk. As the helicopter gains airspeed, the advancing blade develops greater lift because of the increased airspeed (for example, if your blades at a hover move at 300 knots and you fly forward at 100 knots, your advancing blade is now moving at a relative speed of 400 knots and your retreating blade is moving at 200). This has to be compensated for in some way, or the helicopter would corkscrew through the air doing faster and faster snap rolls as airspeed increased.

Dissymetry of lift is compensated for by BLADE FLAPPING . Because of the increased airspeed (and corresponding lift increase) on the advancing blade, it flaps upward. Decreasing speed and lift on the retreating blade causes it to flap downward. This INDUCED FLOW through the rotors system changes the angle of attack on the blades and causes the upward-flapping advancing blade to produce less lift, and the downward-flapping retreating blade to produce a corresponding lift increase. Kinda spooky, huh? Anyway, it all balances out and the lift is equal across the disk.

Dissymetry of lift was discovered by a Spaniard...

Juan de la Cierva - Wikipedia, the free encyclopedia

Juan De la Cierva (21 September 1895 – 9 December 1936) was a Spanish Civil Engineer and pilot. His most famous accomplishment was the invention in 1920 of the Autogiro, a single-rotor type of aircraft that came to be called autogyro in the English language. After four years of experimentation, De la Cierva developed the articulated rotor which resulted in the world's first successful flight of a stable rotary-wing aircraft in 1923 with his C.4 prototype.

Dissymmetry of lift - Wikipedia, the free encyclopedia

Dissymmetry of lift in rotorcraft aerodynamics refers to an uneven amount of lift on opposite sides of the rotor disc. It is a phenomenon that affects single-rotor helicopters in lateral flight, whether the direction of flight be forwards, sideways or in reverse.

To put Cierva's discovery in simpler language...

A rotor system consist of a central hub and the rotor blades. Assume two blades for now. When in motion we have one blade moving into the airflow but the other blade actually retreating from the same airflow. Cierva attended a 1922 Madrid Don Quixote production with an operating windmill on stage. He noticed that the windmill's blades flapping slightly through each revolution. At that time, all autogyro rotor systems were rigid, in blades and in how they attach to the hub. Cierva decided to hinge them and the result: When one blade is moving into the airflow it would flap upward, losing some lift. The other blade which is in retreat from the airflow would flap downward, producing lift. The laws of physics took over and both blades would balance each other out. Cierva's discovery and how to compensate for the autogyro's unique aerodynamics allowed the helicopter to hover AND to have forward speed greater than two-digit mph. The 'articulated rotor' was that hinge system to allow the blades to flap, or to be flexible in their motions.

As helicopter development improve in performance over time, thanks to Cierva, loading weight inevitably increases and that led to the addition of additional blades to improve lift capability but because of the rotor hinge system, the entire rotor assembly itself increases in mechanical complexity and weight. Increased mechanical complexity increases manufacturing and maintenance costs. To keep manufacturing and maintenance costs under control, keep the two-blade configuration but increase engine power and blade length. There has to be balances for all factors, from economics to mechanical engineering, and they all must comply with the laws of physics such as a variable rotor length development...

Helicopter Blade Technology - Variable Length Rotor - Video - Breakthrough Awards - Popular Mechanics

Helicopter performance depends on the length of the rotor blades. For heavy lifting, a large rotor works best, but short blades reduce drag and ultimately allow for higher maximum speeds. Farhan Gandhi, a Penn State University professor of aerospace engineering, has devised an elegant, simple way to achieve both configurations in the same aircraft, using the same rotor.

A rotor blade that changes length has been a long-contemplated, never-achieved goal.

It may be counterintuitive, but higher helicopter speeds require fewer rpms, so conventional rotorcraft—such as this Black Hawk—could also benefit. The rotor would be 54 ft. at 258 rpm (maximum engine power). But the blades could be shortened to 40 ft., allowing the helicopter to fly through urban areas or land in tight quarters.

So preference for a two-blade rotor system over three- or four- is not about lift, which greater blade count do provide, but about mechanical complexity and commensurate costs. Proof of this is in the AH-1Z Super Cobra model...

AH-1Z Viper - Wikipedia, the free encyclopedia

The AH-1Z's new bearingless, hingeless rotor system has 75% fewer parts than that of four-bladed articulated systems.

...And many other four-blade rotor systems out there...

Aircraft in Detail - Helicopter Rotorhead Image Gallery Index

Eurocopter AS365N Dauphin 2
Four-blade hingeless main rotor, Starflex glass-fiber/carbon-fiber hub.

Eurocopter EC155B (AS365N4)
Five-blade hingeless main rotor, Spheriflex glass-fiber/carbon-fiber hub.

Eurocopter EC665 Tiger
Four-blade hingeless FEL main rotor consisting of only 24 parts (w/o bolts and bushings).

Hindustan Dhruv (ALH)
Four-blade FEL hingeless main rotor head with fiber-elastomeric bearings sandwiched between two CFRP star plates (same technology as EC665). Blades are manually foldable.

Sikorsky H-53 Sea Stallion (S-65)
Six-blade fully articulated main rotor with titanium and steel hub. Hydraulically folding blades.

Sikorsky H-60 Blackhawk / Seahawk (S-70)
Four-blade articulated main rotor with one-piece forged titanium head and elastomeric blade retention bearings.

Notice the difference between the two Sikorskys and the rest?

What is this hingeless rotor system when there is a need for each blade to have some independent flexing and the blades balance each other out as the laws of physics demands to eliminate 'dissymetry of lift' phenomenon?

The laws of physics does not say there must be a hinge system. The laws of physics say that if we want to eliminate the 'dissymetry of lift' phenomenon, we must allow each blade to have independent flexing movement. How to do that is our problem. Cierva created the hinged rotor blades. Modern materials science give us -- COMPOSITE. Both solutions applied to the same problem. Composite materials allowed rotor blades to flex as the laws of physics demands, reduces hub mechanical complexity which reduces manufacturing and maintenance costs and allow greater than two-blades rotors.

The AH-1Z Cobra model is a four-blade rotor system and is %75 mechanically less complex than its predecessors. We could have remained with a two-blade system but be hingeless and composites but why should we when a hingeless composited four-blade system give us additional performance benefits at minimum mechanical complexity increase? Improved performance, reduction in mechanical complexity out in the field and still obey the laws of physics.

 

[Chanakyaa]

Breaking News is that India has tested its own Combat Helicopter : LCH.

Now we will certainly have no issue with numbers as it will be cheap, easy to repair and more over 'made in india'

Jai Ho.

 

[desiman]

Super hind

man that thing looks mean, russians really know how to make some eye candy lol

 

[PLAextream]

man that thing looks mean, russians really know how to make some eye candy lol

how would front seat pilot will see if that bulky thing remains in front .

 

[Bull]

IAF Fighter vs PAF fighter and Tank Vs Tank is udnerstandble as it might occur in a war, but when is Heli going to take on a heli.

Anyways IAF helis arnt dedicated attack helis but utility helis with combat roles.

 

[Chanakyaa]

@bull
India has Indegenious LCH.

 

[Iggy]

@bull
India has Indegenious LCH.

Mate its just a protype..long way to go buddy long way to go ..let them evaluate it..correct the problems..remembers its our first attack heli...so problems can occur ..

 

[AchtungSpitfire]

So wait the majority of the Indian helo fleet comes under the InAF? Surprised the Army lost that turf war.

If the Apache ever enters the mix it'll be game over for the opponent.