DARPA DiskRotor

CammNut

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Check out Steve Trimble's blog on flightglobal

http://www.flightglobal.com/blogs/the-dewline/2007/10/boeings-next-big-vtol-surprise.html

It seems Boeing has a DARPA contract to study a disk rotor helicopter. Steve has located a Swiss company with a similar design (and some cool artwork):

www.diskrotor.com

And there has been a previous thread of secretprojects somewhere about the Modus Verticraft.
 

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Swiss stuff away - DARPA should move along recent way with An-72 and immidiately hire prof. Pavlov from Kazan with his L-410-based Diskolyot)))
http://vtol.boom.ru/rus/Pavlov/index.html
 

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Here's its long lost British grand-dad. 1958 Royal Aircraft Establishment study for a high-speed anti-submarine aircraft. Rotors folded by hitting the brake and their momentum made them flip into the disc, which formed the fixed wing. More details in Air Britain Aeromilitaria from a couple of years ago. I'll dig it out the reference when I get home.

KB
 

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Tiawan's Modus was also looking at a disk-rotor concept. I was under the impression that this was still an active project??
 

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I spoke to the inventor of the Modus Verticraft earlier this year. I also have a paper he gave at the AHS Forum this year. He is still looking for a backer. The Taiwan deal fell through years ago. He was hoping to get a small US Air Force Research Laboratory contract to windtunnell just the disc rotor, to investigate the transition from rotor- to wing-borne flight. But I have not heard anything.

The design has evolved a bit - the retractable blades are now more like GE90 fan blades than traditional rotor blades

I have also communicated with George Vranek, the guy behind the images on the diskrotor.com website, and he says he proposed the disk rotot idea to DARPA earlier this year - so maybe that's what started all this
 
Kelly Bushings said:
More details in Air Britain Aeromilitaria from a couple of years ago. I'll dig it out the reference when I get home. KB.

Kelly, any success in finding the reference and any further description? Thanks! Mike.
 
Via magic hint from Mike Hirchberg, we know that... http://www.darpa.mil/tto/Programs/DiscRotor.htm
 

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You'd think DARPA was burnt enough with the Heliplane and CRW. But it is an important mission to fulfill...maybe better luck this time?
 
Just call me Ray said:
Hey cool free AWACS coverage :)

I don't even want to begin thinking about how you would transfer high bandwidth bulk data from a high speed disk to the main body.
 
ouroboros said:
Just call me Ray said:
Hey cool free AWACS coverage :)

I don't even want to begin thinking about how you would transfer high bandwidth bulk data from a high speed disk to the main body.

Probably the same with they do with other rotating-disc AWACS. ;) The real question is how do you get the radar to hold together when the disc is rotating at several hundred RPMs.
 
Hi,

http://www.aviationweek.com/aw/blogs/defense/index.jsp?plckController=Blog&plckScript=blogScript&plckElementId=blogDest&plckBlogPage=BlogViewPost&plckPostId=Blog%3A27ec4a53-dcc8-42d0-bd3a-01329aef79a7Post%3A714a4d2e-9a56-4547-8fde-6292a3789d39
 

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The real question for DARPA will be if the weight and drag penalty of the disk is worth the VTOL performace.
 
"Is there a need for VSTOL AWACS? "

You should have asked the Royal Navy after their Falklkand experiences ... B)
 
Anything looks better than this ;D
 

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Jemiba said:
"Is there a need for VSTOL AWACS? "

You should have asked the Royal Navy after their Falklkand experiences ... B)
I meant US military. I can only think of the marines needing VTOL, but does AWACS fit into their doctrine at all?

P.S. the haweyes would do fine with the Royal Navy in the near future.
 
i really doubt there is any intention of attempting to put a radar in the disk, although for DARPA anything is possible.
 
Hi,

http://www.theregister.co.uk/2008/09/05/darpa_disco_copter/
 

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yasotay said:
i really doubt there is any intention of attempting to put a radar in the disk, although for DARPA anything is possible.

Yeah, I was just joking, but as they say, the joke ran away! :D
 
It looks like the drawing above could work if instead of an Allison 250 that poor Loach had a T64...(make that two just for safety) ;)

seriously, what's with the dinky rotor? there is only so much you can bend the laws of physics.
 
Hi,

http://img256.imageshack.us/i/1032924956hv7.jpg/
 

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I must be getting old. When I saw someone reference a "disco-copter" I immediately thought of a helicopter with big speakers, lights, and a mirrored ball hanging beneath, belting out Bee Gees tunes.

Where are my bellbottoms? (Psst! We could use a geezer smiley!)
 
New stuff found at AW&ST blogs. B)

Boeing has concluded that a disc-rotor vertical take-off and landing aircraft is "feasible, but not easy". The company is studying a high-speed combat search-and-rescue concept under DARPA's DiscRotor program, and will test a model of the telescoping-blade rotor in the windtunnel next year.

Invented by Danish engineer Jacob Ellehammer early last century, the disc-rotor has a disc with blades attached that acts as a helicopter rotor in vertical flight and a wing in forward flight. Retracting the blades into the disc reduces drag in fixed-wing mode. NASA studied a Mach 0.85 disc-rotor in the late 1960s and took another look at the concept in the early 1990s.

The disc-rotor promises to combine the high cruise speed and altitude of a fixed-wing aircraft with the low-speed and hover capability of a rotary-wing aircraft, with low hover downwash and reduced radar signature when the blades are retracted. The low lift-to-drag ratio of the disc as a wing is an issue, so Boeing has added a swept wing to provide efficient lift in forward flight.

Boeing's conceptual CSAR DiscRotor has a dash speed of 360kt and radius of 400nm with a payload exceeding 2,400lb,, and at a mid-mission gross weight of around 31,000lb can maneuver at up to 4g, and hover in ground effect at 12,000ft density altitude - performance figures that are competitive with a tilt-rotor. Blades retracted and wings folded, DiscRotor takes up less deck space than a MV-22 or CH-53E

Developing a mechanism that will reliability and repeatably retract and extend the blades under flight loads (including centripetal forces) is the central technical challenge of the DiscRotor program, Boeing technical fellow Michael McVeigh told the International Powered Lift Conference in Philadelphia earlier this month.

To address the challenge, Boeing is building a 20%-scale rotor model for windtunnel testing next summer at speeds up to 150kt. This will have four blades, each with three telescoping sections, and a rigid hub with blade retraction and pitch-change mechanisms, and an eight-segment disc fairing.

The DiscRotor has an integrated propulsion system using two turboshaft engines fitted with fans so they can also generate forward thrust. Shaft power goes to the main gearbox to power the rotor and a pair of wing-mounted, cross-shafted ducted propellers that provide the majority of the thrust in fixed-wing mode.

Engine core and bypass exhaust goes aft to a thrust-vectoring nozzle in the tail that provides anti-torque control in helicopter mode, and during conversion between modes when the disc is being braked or accelerated, and also provides auxiliary thrust in forward flight. The disc is stopped in fixed-wing mode to avoid gyroscopic effects.

In helicopter-mode flight, the DiscRotor has conventional rotor collective and cyclic pitch controls. Hover anti-torque and yaw maneuvering is provided 70% by the tail thruster, and 30% by differential thrust on the ducted props. Rotor controls are phased out at 120kt and yaw control provided by the thruster and winglets, and pitch and roll control by wing flaperons.

Mid-way through Phase 1b of DARPA's program, McVeigh says "DiscRotor looks feasible, but not easy. It offers a large increase in cruise speed, but with several large technical challenges." The rotor model tests next year should help decide whether the concept is worth pursuing.
http://www.youtube.com/v/pg6LuwyNIxk

Text by by Graham Warwick at 10/22/2010 9:01 AM CDT.
All graphics and video by Boeing/DARPA
Sources: Boeing Updates on DARPA's DiscRotor
High-Speed VTOL Goes for a Spin
 

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Jeesh, you'd think with a design like that, Boeing would want to team up with the X3 EADS guys...


I wonder if the telescopic blades would have any carryover to tiltrotors to improve disk loading. Weren't there some proposals in the past to do "blade within blade" style telescopic rotors, as a means of reducing the rotor disk diameter when in forward cruise?
 
ouroboros said:
Jeesh, you'd think with a design like that, Boeing would want to team up with the X3 EADS guys...


I wonder if the telescopic blades would have any carryover to tiltrotors to improve disk loading. Weren't there some proposals in the past to do "blade within blade" style telescopic rotors, as a means of reducing the rotor disk diameter when in forward cruise?

I think Sikorsky looked at that when they were tinkering with tilt rotor in the late 80's to early 90's.
 
fightingirish said:
New stuff found at AW&ST blogs. B)

[size=10pt]
.......Invented by Danish engineer Jacob Ellehammer early last century......

http://www.ctie.monash.edu.au/hargrave/ellehammer.html
http://en.wikipedia.org/wiki/Jacob_Ellehammer

;D

Regards & all,

Thomas L. Nielsen
Luxembourg (expatriated Dane)
 
Hi,

http://www.myconfinedspace.com/2008/09/26/darpa-discopter-concept/
 

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Ok, question? While Boeing 'admits' that the disk-rotor would be "very difficult" but "possible" I seem to undertand that a majority of this is the aerodynamics of the "disk-wing" itself, is that correct?

So, why not a "traingle" or "hexagon" type wing instead, especially if you're going to have to have fairly large wings in addition to the rotor housing itself?

Links:
http://www.secretprojects.co.uk/forum/index.php/topic,2140.msg64078.html#msg64078

http://www.secretprojects.co.uk/forum/index.php/topic,2140.msg64099.html#msg64099

Randy
 
There are some indications that a successful manned DiskRotor design might be easier to achieve than an unmanned one.
 
IMHO, it's not so much the telescopic part, as doing all that while blades are 'swashing'...


Don't rotor blades' pitch vary significantly along their length ? That's another factor to contend with...


Ironically, an 'auto-gyro' version might be straight-forward...
 
...
 

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Nik said:
IMHO, it's not so much the telescopic part, as doing all that while blades are 'swashing'...


Don't rotor blades' pitch vary significantly along their length ? That's another factor to contend with...

Yep. There's a Sikorsky in-house video out there where they mounted a camera on the rotorhead of a CH-53 and pointed it down the length of the blade. That thing is all over the place in flight.
 
Nik said:
IMHO, it's not so much the telescopic part, as doing all that while blades are 'swashing'...


Don't rotor blades' pitch vary significantly along their length ? That's another factor to contend with...


Ironically, an 'auto-gyro' version might be straight-forward...

In forward flight, yes. However, this isn't supposed to go as fast as a helicopter would with it's rotor in helo mode, so it won't be as much of a problem with this since they will be retracted well before it reaches the forward operating speeds of a standard helo.
 
fightingirish said:
The DiscRotor has an integrated propulsion system using two turboshaft engines fitted with fans so they can also generate forward thrust. Shaft power goes to the main gearbox to power the rotor and a pair of wing-mounted, cross-shafted ducted propellers that provide the majority of the thrust in fixed-wing mode.

Engine core and bypass exhaust goes aft to a thrust-vectoring nozzle in the tail that provides anti-torque control in helicopter mode, and during conversion between modes when the disc is being braked or accelerated, and also provides auxiliary thrust in forward flight. The disc is stopped in fixed-wing mode to avoid gyroscopic effects.

Has anybody previously heard about turbo-shaft engines with bypass air? What would be the point?

Also, looking into my crystal ball, I foresee the gearbox leading to massive cost over-runs.
 
AdamF said:
fightingirish said:
The DiscRotor has an integrated propulsion system using two turboshaft engines fitted with fans so they can also generate forward thrust. Shaft power goes to the main gearbox to power the rotor and a pair of wing-mounted, cross-shafted ducted propellers that provide the majority of the thrust in fixed-wing mode.

Engine core and bypass exhaust goes aft to a thrust-vectoring nozzle in the tail that provides anti-torque control in helicopter mode, and during conversion between modes when the disc is being braked or accelerated, and also provides auxiliary thrust in forward flight. The disc is stopped in fixed-wing mode to avoid gyroscopic effects.

Has anybody previously heard about turbo-shaft engines with bypass air? What would be the point?

Also, looking into my crystal ball, I foresee the gearbox leading to massive cost over-runs.

"Shaft power goes to the main gearbox to power the rotor and a pair of wing-mounted, cross-shafted ducted propellers that provide the majority of the thrust in fixed-wing mode."
 

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