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Future Helicopters

a_majoor

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NASA works on active rotors which have the potential to make helicopter flight more efficient. If this pans out, retrofitting existing helicopters is an option providing increases in performance and fuel economy:

http://www.nasa.gov/topics/aeronautics/features/smart_rotor.html

Future Helicopters Get SMART

Helicopters today are considered a loud, bumpy and inefficient mode for day-to-day domestic travel—best reserved for medical emergencies, traffic reporting and hovering over celebrity weddings.

But NASA research into rotor blades made with shape-changing materials could change that view.

Twenty years from now, large rotorcraft could be making short hops between cities such as New York and Washington, carrying as many as 100 passengers at a time in comfort and safety.

Routine transportation by rotorcraft could help ease air traffic congestion around the nation's airports. But noise and vibration must be reduced significantly before the public can embrace the idea.

"Today's limitations preclude us from having such an airplane," said William Warmbrodt, chief of the Aeromechanics Branch at NASA's Ames Research Center in California, "so NASA is reaching beyond today's technology for the future."

The solution could lie in rotor blades made with piezoelectric materials that flex when subjected to electrical fields, not unlike the way human muscles work when stimulated by a current of electricity sent from the brain.

Helicopter rotors rely on passive designs, such as the blade shape, to optimize the efficiency of the system. In contrast, an airplane's wing has evolved to include flaps, slats and even the ability to change its shape in flight.

NASA researchers and others are attempting to incorporate the same characteristics and capabilities in a helicopter blade.

NASA and the Defense Advanced Research Projects Agency, also known as DARPA, the U.S. Army, and The Boeing Company have spent the past decade experimenting with smart material actuated rotor, or SMART, technology, which includes the piezoelectric materials.

"SMART rotor technology holds the promise of substantially improving the performance of the rotor and allowing it to fly much farther using the same amount of fuel, while also enabling much quieter operations," Warmbrodt said.

There is more than just promise that SMART Rotor technology can reduce noise significantly. There's proof.

The only full-scale SMART Rotor ever constructed in the United States was run through a series of wind tunnel tests between February and April 2008 in the National Full-Scale Aerodynamics Complex at Ames. The SMART Rotor partners joined with the U.S. Air Force, which operates the tunnel, to complete the demonstration.

A SMART Rotor using piezoelectric actuators to drive the trailing edge flaps was tested in the 40- by 80-foot tunnel in 155-knot wind to simulate conditions the rotor design would experience in high-speed forward flight. The rotor also was tested at cruise speed conditions of 124 knots to determine which of three trailing edge flap patterns produced the least vibration and noise. One descent condition also was tested.

Results showed that the SMART Rotor can reduce by half the amount of noise it puts out within the controlled environment of the wind tunnel. The ultimate test of SMART rotor noise reduction capability would come from flight tests on a real helicopter, where the effects of noise that reproduces through the atmosphere and around terrain could be evaluated as well.

The test data also will help future researchers use computers to simulate how differently-shaped SMART Rotors would behave in flight under various conditions of altitude and speed.

For now that remains tough to do.

"Today's supercomputers are unable to accurately model the unsteady physics of helicopter rotors and their interaction with the air," Warmbrodt said. "But we're working on it."
 
It seems that a company recently dusted off the V-12 design and is about to put the joys of vertical flight and a good night's sleep into production...
 
New designs got to start somewhere... I'm sure the same things were said about the very first helicopter and the very first air plane...
 
Did everything ecept the noise bit.....
http://www.asra.org.au/rotordyn.htm

My family and I traveled through the Soviet Union by camper in the summer of 1970, we were detoured past a large Soviet base and I saw this aircraft flying overhead.

http://en.wikipedia.org/wiki/Mil_Mi-12
 
Unmanned helicopters are getting a workout:

http://www.army.mil/article/71269/Army_to_deploy_vertical_take_off_UAS/

Army to deploy vertical take-off UAS

December 22, 2011

By Kris Osborn, ASA(ALT) Public Affairs
VTOL UAS
A Vertical-Take-Off-and-Landing Unmanned Aerial System.
Related Links

    Army.mil: Science and Technology News
    STAND-TO!: U.S. Army Roadmap for Unmanned Aircraft Systems: 2010-2035
    Assistant Secretary of the Army for Acquisition, Logistics and Technology -- ASA(ALT)

WASHINGTON (Dec. 22, 2011) -- The U.S. Army is using a hybrid-type acquisition approach to develop a helicopter-like, Vertical-Take-Off-and-Landing Unmanned Aerial System with a so-called ARGUS wide-area surveillance sensor suite designed to beam back information and images of the surrounding terrain, service officials said.

Beginning in May or June of 2012, the Army will deploy three Boeing-built A160 Hummingbird Vertical-Take-Off-and-Landing Unmanned Aerial Systems, or VTOL-UAS, to Afghanistan as part of a Quick Reaction Capability, an acquisition approach aimed at delivering cutting-edge and emerging technologies to theater to add capability and inform requirements while simultaneously developing a formal Program of Record approach, said Lt. Col. Matthew Munster, product manager, UAS Modernization.

"These aircraft will deploy for up to one full year as a way to harness lessons learned and funnel them into a program of record," Munster said.

The formal VTOL Program of Record will involve a full and open competition among many vendors able to propose UAS solutions able to meet the desired requirements, he added.

Army VTOL UAS program developers and engineers are now finishing up some wiring work on the A160 aircraft and performing ground tests with the ARGUS sensor suite.

"The ARGUS sensor suite has never been flown on this platform before so we have to make sure that the integration is complete. We are finishing that up now and adding some different types of antennas. We begin flight testing of the UAS at Yuma Proving Grounds, Arizona, early next year," Munster said.

The VTOL aircraft will give forward-positioned Army units the ability to deploy a wide-area UAS Intelligence, Surveillance Reconnaissance, or ISR, asset without needing access to a runway.
 
DARPA wants to explore the idea of ultra fast VTOL aircraft. I don't think that anything "conventional" will be able to fulfill their conditions, so it will be interesting to see what exactly comes from this:

http://www.wired.com/dangerroom/2013/02/darpa-vtol-x/

Darpa Wants to Rethink the Helicopter to Make It Go Way Faster
BY SPENCER ACKERMAN02.25.132:00 PM

Helicopters are great. They’re maneuverable in very tight spaces, they haul heavy things relative to their small sizes — and, very importantly, they take off and land vertically, removing the need for a big airstrip or aircraft-carrier deck. That function is so important to the military that the U.S. designed fixed-wing aircraft to do the same thing, like the Marines’ iconic Harrier jet or their weird tilt-rotor Osprey.
And they actually all suck, according to the Pentagon’s blue-sky researchers at Darpa, who are launching an effort to blow up and re-imagine helicopters, jump jets and tilt-rotors. It’s time to make these “VTOL” aircraft — the collective term for Vertical Take-Off and Landing — way, way faster, without sacrificing their ability to hover or other functionality.

Like any aircraft, VTOLs are most vulnerable to enemy attack when they’re taking off and landing. But unlike other aircraft, they’re slow to ascend and descend, a particular problem when an adversary lurking nearby knows exactly what pattern the VTOLs will use to get off the ground and back onto it. And when they’re flying, they’re not going nearly as fast as something with, say, a jet engine. It’s a problem the U.S. military has often encountered in warzones. Anyone who’s taken a ride on a Blackhawk or a Chinook in Afghanistan or Iraq has been very thankful for the guy with the .50-caliber gun hanging out the open back of the helo.

Hence Darpa’s newest aircraft program. It’s called the VTOL X-Plane and officially launches Monday. The idea is to rethink the designs of anything that takes off and lands vertically, to make it faster; hover and cruise more efficiently; and haul more stuff. By the time it’s done in 52 months, it just might result in an aircraft that doesn’t look at all like a helicopter, jump jet or tilt-rotor.

“What we’re interested in doing is flying much faster than we have been able to do with helicopters,” program manager Ashish Bagai told reporters on a conference call. Helos and other VTOL aircraft typically max out at 170 knots. Bagai wants the X-Plane to do 300. “We want to fly at improved efficiencies, both in hover and at forward flight,” he said, “and we want to demonstrate this is possible without sacrificing the ability to do useful work. And to do this concurrently is a very big challenge.”

It’s also not springing up from specific improvements in helicopter or other VTOL capability in the aerospace industry. Nor does it arise from any tech innovations Darpa sees on the horizon. “We have seen in the community a few isolated and novel approaches to addressing this problem but we’re in danger of suffering an attrition in our technology bases,” Bagai said. “This is an opportunity Darpa would like to put forth to advance the state of the art, well beyond where we are today.”

Good luck with that. Helicopters usually get faster by adding power and messing with the rotor placements. (See, for instance, Sikorsky’s funky ’70s-era designs.) But that typically compromises their ability to hover. Nor, Bagai conceded, have fixed-wing VTOLs cracked the speed/hover/power problem. And the V-22 Osprey tilt-rotor has endured more than its fair share of challenges.

All of which raises questions about the VTOL X-Plane’s ability to actually deliver on its promises. Bagai thinks there’s an opportunity for “hybridization” by mashing up the fixed-wing and helicopter design communities, but like many Darpa projects, the program will pulse those communities rather than take advantage of improvements on the cusp of maturity.

Darpa’s setting a “very aggressive” development schedule, Bagai said, that’s targeting a flight test in 42 months. Ten months later, when the program ends, “we want to have demonstrated all our key objectives and have a flying aircraft available,” he said. If it fails, helicopters, jump jets and tilt-rotors won’t be any worse off. If it succeeds, the VTOL X-Plane pretty much represents their next generation.
 
Crossfire said:
Oh the humanity!!
Couldn't resist!
 
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While not a helicopter, the Hunting H-126 research aircraft used "Jet Flaps" (know known as "Blown Flaps") to achieve remarkable STOL performance. The downside was since 60% of the thrut was diverted through the slots at the rear of the wing, there was little power for forward flight (although as a proof of principle research craft that wasn't really much of an issue).

Developing this idea further could be the 80% solution, providing excellent STOL performance from very small airfields, good low speed performance and the high speed "dash" that DARPA wants. How to do the hovering/vertical flight portion with this principle needs the attention of much smarter people:

http://en.wikipedia.org/wiki/Hunting_H.126
 
Thucydides said:
While not a helicopter, the Hunting H-126 research aircraft used "Jet Flaps" (know known as "Blown Flaps") to achieve remarkable STOL performance. The downside was since 60% of the thrut was diverted through the slots at the rear of the wing, there was little power for forward flight (although as a proof of principle research craft that wasn't really much of an issue).

Developing this idea further could be the 80% solution, providing excellent STOL performance from very small airfields, good low speed performance and the high speed "dash" that DARPA wants. How to do the hovering/vertical flight portion with this principle needs the attention of much smarter people:

http://en.wikipedia.org/wiki/Hunting_H.126

So we should just buy all the upgraded Harriers that the British mothballed then? :nod:
 
daftandbarmy said:
So we should just buy all the upgraded Harriers that the British mothballed then? :nod:

Might be nice.

Since DARPA is looking for something that combines the vertical flight capabilities of a helicopter with the forward flight capabilities of a fixed wing aircraft, something like an evolved Harrier might actually be the way to go.
 
Thucydides said:
something like an evolved Harrier might actually be the way to go.

Like an F35B.....?

That still does not offer helicopter-like capabilities, though.
 
What's the loiter time of an F-35B or Harrier in hover?  5 min?  That was just a complete guess, but I can't imagine it's much longer than that, unless your carrying fuel instead of bombs.

The vertical take off offers great flexibility, but I don't think you can compare a Harrier to a helo.  Most simply because helos are a manoeuvre force  that is commanded at the tactical level, and jets are not.





 
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