How Apache Helicopters Work

How Stuff Works website ^ | NA | Tom Harris

[prisoner6]

How Apache Helicopters Work
by Tom Harris

The Apache helicopter is a revolutionary development in the history of war. It is essentially a flying tank -- a helicopter designed to survive heavy attack and inflict massive damage. It can zero in on specific targets, day or night, even in terrible weather. As you might expect, it is a terrifying machine to ground forces.

In this edition of HowStuffWorks, we'll look at the Apache's amazing flight systems, weapons systems, sensor systems and armor systems. Individually, these components are remarkable pieces of technology. Combined together, they make up an unbelievable fighting machine -- the most lethal helicopter ever created.

Power and Flight
At its core, an Apache works pretty much the same way as any other helicopter. It has two rotors that spin several blades. A blade is a tilted airfoil, just like an airplane wing. As it speeds through the air, each blade generates lift. (See How Airplanes Work to find out how lift is generated.)

The main rotor, attached to the top of the helicopter, spins four 20-foot (6-meter) blades. The pilot maneuvers the helicopter by adjusting a swash plate mechanism. The swash plate changes each blade's pitch (tilt) to increase lift. Adjusting the pitch equally for all blades lifts the helicopter straight up and down. Changing the pitch as the blades make their way around the rotation cycle creates uneven lift, causing the helicopter to tilt and fly in a particular direction. (See How Helicopters Work for a full explanation.)

As the main rotor spins, it exerts a rotation force on the entire helicopter. The rear rotor blades work against this force -- they push the tail boom in the opposite direction. By changing the pitch of the rear blades, the pilot can rotate the helicopter in either direction or keep it from turning at all. An Apache has double tail rotors, each with two blades.

Photo courtesy U.S. Department of Defense
The rotor assembly on an AH-64A Apache

The newest Apache sports twin General Electric T700-GE-701C turboshaft engines, boasting about 1,700 horsepower each. Each engine turns a drive shaft, which is connected to a simple gear box. The gear box shifts the angle of rotation about 90 degrees and passes the power on to the transmission. The transmission transmits the power to the main rotor assembly and a long shaft leading to the tail rotor. The rotor is optimized to provide much greater agility than you find in a typical helicopter.

The core structure of each blade consists of five stainless steel arms, called spars, which are surrounded by a fiberglass skeleton. The trailing edge of each blade is covered with a sturdy graphite composite material, while the leading edge is made of titanium. The titanium is strong enough to withstand brushes with trees and other minor obstacles, which is helpful in "nap-of-the-earth" flying (zipping along just above the contours of the ground). Apaches need to fly this way to sneak up on targets and to avoid attack. The rear tail wing helps stabilize the helicopter during nap-of-the-earth flight as well as during hovering.

Photo courtesy U.S. Department of Defense
The Apache's blades and wings detach for easier transport.

You could say, based on all this information, that the Apache is just a high-end helicopter. But that would be like calling James Bond's Aston Martin just a high-end car. As we'll see in the next few sections, the Apache's advanced weaponry puts it in an entirely different class.

[prisoner6]

This is an excerpt from the website. For civies like me I thought it was pretty cool. There's LOTS more than what I posted.

prisoner6

[Free the USA]

http://www.freerepublic.com/perl/bump-list

[rs79bm]

That's interesting. Support Free Republic where are you???

[stlrocket]

[Cacophonous]

As an old warrant officer once told a green lieutenant, on being asked how a particular piece of anti-aircraft artillery worked: "Works damned good, Lieutenant, and that's all you need to know."

[prisoner6]

That's a good one LOL! I ahve to pass it along to one of my friends, a retired USAF COL. Flew Just about everything but mostly bombers into Germany in WWII. Lasted through Vietnam though and did get to fly a few fighters.

We often talk about the dynamics of flight and interestingly enough he doesn't care too much, just so long as the craft (his) stays airborne.

prisoner6

[Balata]

Just for fun, check this out.

Ride in a Huey

[Stingray51]

Regarding the claim that the Apache does its job effectively even in "terrible weather", count me among the skeptics. But that's based on what I saw in the Army over ten years ago. Does anyone more recent have any insight into the Apache's track record (in training) when it comes to acquiring and engaging targets on dark, windy, stormy nights?

Fortunately, this question doesn't have much to do with the desert.

[KneelBeforeZod]

very suspicious how many articles show up both here and on fark.com

[taxed2death]

I was under the impression that they can't carry as many munitions as origionally planned, at altitude....engines don't have enough balls.

[prisoner6]

I think Drew is a closet FReeper. Also check Albinoblacksheep.com for some strange stuff amd Rotten.com for the bizzarre.

prisoner6 (thanks for the reminder, time to hit Fark!)

[ladtx]

As an "old" Warrant Officer, my answer was always:

"It works damn good, don't f*** with it!"

[Clive]

The Apache doesn't like Saudi sand or Balkan mud.

Doesn't appear to be too keen on blizzards either.

But it loves southern CAlifornia.

[prisoner6]

This summer I was near Pittsburgh in wooded lot overlooking the Ohio river and checking out a Fiero I was bringing home for a project car. W was going to be visiting the area close by the next day. Suddenly there was this LOUD chopper noise and an Apache popped up from blow the cliff where the car was.

The guys inside hovered there checkng me out for a few minutes, then after I waved and pointed to the Fiero, the guys waved back, wiggled the copter and took off down river.

At the time the copter popped up so quickly it startled me. Later I got to thinkging about how I didn't really notice the noise until it came above the cliff and tree line.

Cool!

prisoner6

[KneelBeforeZod]

there are actually a lot of FReepers over there. Well a few. One of them got kicked off, but I won't give his name though.

But fark does a funny thing with people they ban. With cookies I guess? If they ban you, only YOU can read your posts.

There are some great conservative photoshops that come out of Fark.

[prisoner6]

If they ban you, only YOU can read your posts.

That's hilarious. If I'm understanding if you get banned you >think< you're posting but >really< only YOU can view the posts! Oh that would be so cool here! The AFR's and others who attack would think they're still spewing their stuff, but in reality no one but them could see it.

prisoner6

[Poohbah]

Oh, jeez, that was a laugh riot!