For almost a century, military bombers have played a significant role in turning the tides of world wars. These heavyweights often provide critical firepower in otherwise unreachable areas.

Despite the pullback of manned bombers in Afghanistan, the military continues to look toward a future of more reliable, accurate and effective bombers. The 2018 Bomber, some experts believe, is the answer.

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The 2018 Bomber, now being developed by Boeing and Lockheed Martin, will be a long-range, penetrating heavy bomber that is flown autonomously by ground personnel.

On April 6, 2009, the Obama administration announced that the 2018 Bomber, also known as the Next Generation Bomber, would not make the cut for the defense budget.

But just last week, long-term funding may have been secured with a bill passed by the Senate Armed Services Committee.

The most advanced and well-known bomber today is the B-2 Spirit, also known as the "stealth bomber." Because of its high maintenance costs and sensitive surface material, the B-2 is beginning to show signs of age.

One of the B-2's main disadvantages, according to John Pike, an expert in defense and director of GlobalSecurity.org, is that it's flown by a pilot who may naturally succumb to a measure of tiredness after a nonstop flight.

"When [the B-2] was used in Kosovo, they flew it directly from Whiteman Air Base, 24 hours over to the target, 10 minutes over the target, and 24 hours back. This is not a very efficient way of putting hot steel on target," Pike says.

"Because of pilot fatigue, the stealth bomber is a stunt, not a plan," Pike says.

Some experts think the Air Force needs an unmanned aerial vehicle (UAV) that is combined with the power of a heavy bomber.

The new 2018 Bomber is air-refueled, long-lasting and reliable, Pike says. With the added UAV components, the new bomber can spend 48 hours over the target area alone.

The first bomber designs, from the early 1900s, look primitive compared to the plans for the 2018.

Here, we take a look at bomber technology through the years — from the two-engine Capronis to the eight-engine B-52s to the pilotless 2018.

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