Sikorsky X2 coaxial heli developments.
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Overdrive,
That's the only picture that I found on the Internet.
CEFOSKEY,
The use of a special 'reverse taper' blade should be interesting; particularly since it may concentrate most of the induced velocity near the outer periphery of the two actuator disks.
IMFU's subliminal April Fools day message may be the critical one.
He knows that Eagle Aviation Technologies made these blades.
He also knows that it's CEO, Emitt Wallace, brought the world the coaxial Air Scooter.
He also knows that the Air Scooter cannot autorotate.
What is IMFU really saying?
That's the only picture that I found on the Internet.
CEFOSKEY,
Surprised you didn't quote this little snippet:
"...So that led to the need for double-ended airfoils close to the hub as part of our scheme for reducing drag due to the rotor hub"
"...So that led to the need for double-ended airfoils close to the hub as part of our scheme for reducing drag due to the rotor hub"
IMFU's subliminal April Fools day message may be the critical one.
He knows that Eagle Aviation Technologies made these blades.
He also knows that it's CEO, Emitt Wallace, brought the world the coaxial Air Scooter.
He also knows that the Air Scooter cannot autorotate.
What is IMFU really saying?
Last edited by Dave_Jackson; 9th May 2008 at 17:45. Reason: Smiley relocated ~ so that there is not any misunderstanding.
Dave,
What I was saying was that it was unusual for you to reference a positive article about a non-symmetrical aircraft without some sort of dig. All better now.
I enjoyed the article, neat pic too. I did not know what an airscooter was, but now I do.
-- IFMU
What I was saying was that it was unusual for you to reference a positive article about a non-symmetrical aircraft without some sort of dig. All better now.
I enjoyed the article, neat pic too. I did not know what an airscooter was, but now I do.
-- IFMU
Last edited by IFMU; 7th May 2008 at 10:06. Reason: put in the airscooter part
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Check the mission brochure for a photo of the hub fairing
http://www.sikorsky.com/sik/Attachme...07_Trifold.pdf
http://www.sikorsky.com/sik/Attachme...07_Trifold.pdf
Last edited by bat1; 11th May 2008 at 17:21. Reason: Couldn't get link to work
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OD
This is the only photo I have seen with the hub. It is a photoshopped version of the photo in sikorsky's x2 mission brochure.
This is the only photo I have seen with the hub. It is a photoshopped version of the photo in sikorsky's x2 mission brochure.
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Originally Posted by Brilliant Stuff
I was made to understand the X2 was ready to fly and would have had it's maiden flight if the Expo had not been scheduled for the same week
CEFOSKEY -- Thanks for keeping us updated on this project. Out of interest, are you with Belcan or UoK?
(You can also thank the union's 2006 strike for putting it behind schedule.)
-- IFMU
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CEFOSKEY, genuine thanks for providing the "view from the hill" on this thread.
I'm now part of a recip engine design analysis team (that's why i've been away), but the fascination with helicopters remains. X2 is the project of projects.
I'm now part of a recip engine design analysis team (that's why i've been away), but the fascination with helicopters remains. X2 is the project of projects.
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Ground Run!
First Ground run w/ blades installed:
HORSEHEADS, N.Y. May 21, 2008 – Sikorsky Aircraft Corp. achieved a major milestone on its X2 TECHNOLOGY™ Demonstrator program by successfully ground testing the aircraft with rotor blades installed and spinning for the first time. Sikorsky is a subsidiary of United Technologies Corp. (NYSE:UTX).
The initial “blades-on” ground test was conducted May 13 and went according to plan. The ground tests are continuing at Sikorsky’s Schweizer Aircraft Corp. rapid-prototyping facility in Horseheads, N.Y., in preparation for the X2 TECHNOLOGY Demonstrator’s first flight.
"The entire X2 TECHNOLOGY Demonstrator Program Team is extremely pleased that we continue to move our experimental program closer and closer to first flight,” said James Kagdis, Program Manager, Advanced Programs. ”We anticipate that reaching this particular milestone, as with those yet to come, will continue to pique the interest of our military, commercial and international customers regarding the potential that X2 TECHNOLOGY could have on their diverse missions around the globe."
The X2 TECHNOLOGY Demonstrator combines an integrated suite of technologies intended to advance the state-of-the-art, counter-rotating coaxial
rotor helicopter. It is designed to demonstrate a helicopter can cruise comfortably
at 250 knots, while retaining such desirable helicopter attributes as excellent low speed handling, efficient hovering and autorotation safety, and a seamless and simple transition to high speed.
Among the innovative technologies the X2 TECHNOLOGY Demonstrator employs are:
·Fly-by-wire flight controls
·Counter-rotating rigid rotor blades
·Hub drag reduction
·Active vibration control
·Integrated auxiliary propulsion system
Sikorsky Aircraft first announced the initiative to develop an integrated suite of technologies called X2 TECHNOLOGY in June 2005. The project is funded solely by Sikorsky.
Sikorsky Aircraft Corp., based in Stratford, Conn., is a world leader in helicopter design, manufacture, and service. The company’s long commitment to safety and innovation is reflected in its mission statement: “We pioneer flight solutions that bring people home everywhere … every time™.“ United Technologies Corp., based in Hartford, Conn., provides a broad range of high-technology products and support services to the aerospace and building systems industries.
See also this article:
http://www.theregister.co.uk/2008/05...2_ground_spin/
First ‘Blades-On’ Ground Runs Conducted Successfully
For Sikorsky’s X2 TECHNOLOGY™ Demonstrator
HORSEHEADS, N.Y. May 21, 2008 – Sikorsky Aircraft Corp. achieved a major milestone on its X2 TECHNOLOGY™ Demonstrator program by successfully ground testing the aircraft with rotor blades installed and spinning for the first time. Sikorsky is a subsidiary of United Technologies Corp. (NYSE:UTX).
The initial “blades-on” ground test was conducted May 13 and went according to plan. The ground tests are continuing at Sikorsky’s Schweizer Aircraft Corp. rapid-prototyping facility in Horseheads, N.Y., in preparation for the X2 TECHNOLOGY Demonstrator’s first flight.
"The entire X2 TECHNOLOGY Demonstrator Program Team is extremely pleased that we continue to move our experimental program closer and closer to first flight,” said James Kagdis, Program Manager, Advanced Programs. ”We anticipate that reaching this particular milestone, as with those yet to come, will continue to pique the interest of our military, commercial and international customers regarding the potential that X2 TECHNOLOGY could have on their diverse missions around the globe."
The X2 TECHNOLOGY Demonstrator combines an integrated suite of technologies intended to advance the state-of-the-art, counter-rotating coaxial
rotor helicopter. It is designed to demonstrate a helicopter can cruise comfortably
at 250 knots, while retaining such desirable helicopter attributes as excellent low speed handling, efficient hovering and autorotation safety, and a seamless and simple transition to high speed.
Among the innovative technologies the X2 TECHNOLOGY Demonstrator employs are:
·Fly-by-wire flight controls
·Counter-rotating rigid rotor blades
·Hub drag reduction
·Active vibration control
·Integrated auxiliary propulsion system
Sikorsky Aircraft first announced the initiative to develop an integrated suite of technologies called X2 TECHNOLOGY in June 2005. The project is funded solely by Sikorsky.
Sikorsky Aircraft Corp., based in Stratford, Conn., is a world leader in helicopter design, manufacture, and service. The company’s long commitment to safety and innovation is reflected in its mission statement: “We pioneer flight solutions that bring people home everywhere … every time™.“ United Technologies Corp., based in Hartford, Conn., provides a broad range of high-technology products and support services to the aerospace and building systems industries.
See also this article:
http://www.theregister.co.uk/2008/05...2_ground_spin/
This comes from that Register article:
Apologies if this has already been covered in this thread but this is the first time that I've seen a mention of this variable rrpm. Is this really going to happen or have the Register managed to get their technologies confused?
One also notes that variable-rotor-revs tech like that of the X2 is quite rare, most whirlycraft spinning their blades at a fixed rate. Boeing's unmanned A160T uses variable-spin, and is said to be "four times quieter" in the hover than a regular copter - not to mention having advantages in fuel economy.
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Where the rubber meets the road.
Many years ago Nick mentioned that Sikorsky does 90% of its helicopter development after the prototype has been built and is in testing. Some might suggest that most of the development should take place after the craft meets the notepad, not after it meets the helipad.
But then, who would dare question The Big Sikorsky?
The full technical information on the performance of the X2 may involve a long wait. Or it may never be made public, since this is a privately funded project. For the fun of technical speculation, and perhaps discussion, the following is put forth.
The blades on the X2 have a reverse taper. Presumably, this is done so that the airfoil portions of the blades are subjected to minimal reverse airflow during fast forward flight. However, this will result in disadvantages. The reverse taper will increase the induced velocity in the outer regions of the two overlaid rotor disks but reduce the induced velocity in their inner regions; as compared to today's conventional rotors. Actuator Disk Theory and Bernoulli's principle assumes that the aerodynamic loading is distributed uniformly over the disk.
During hover; ~ One disadvantage may be the reduction in the Figure of Merit; particularly when considering that Dr. Gordon Leishman has said;- "... it had taken the industry sixty years to realize a helicopter with an average increase in rotor hovering efficiency (figure of merit or FM) of only 13%".
During cruise; ~ Another disadvantage may be the reduced Lift/Drag Ratio. In addition, the aft-located propeller (pusher configuration) will probably strip away some of the lift that is generated by the coaxial rotors. Consider the remark by Carson "...on average, the maximum L/D of the helicopter has only increased by less than 10% in the last 30 or more years."
If the above concerns are valid, can the X2 be a viable contender in the field of VTOL craft?
Dave
_________________________________
Bravo73,
The earlier XH-59A ABC had a two-speed transmission. To my recollection, a variable speed transmission for the X2 has been inferred but never stated outright.
Many years ago Nick mentioned that Sikorsky does 90% of its helicopter development after the prototype has been built and is in testing. Some might suggest that most of the development should take place after the craft meets the notepad, not after it meets the helipad.
But then, who would dare question The Big Sikorsky?
The full technical information on the performance of the X2 may involve a long wait. Or it may never be made public, since this is a privately funded project. For the fun of technical speculation, and perhaps discussion, the following is put forth.
The blades on the X2 have a reverse taper. Presumably, this is done so that the airfoil portions of the blades are subjected to minimal reverse airflow during fast forward flight. However, this will result in disadvantages. The reverse taper will increase the induced velocity in the outer regions of the two overlaid rotor disks but reduce the induced velocity in their inner regions; as compared to today's conventional rotors. Actuator Disk Theory and Bernoulli's principle assumes that the aerodynamic loading is distributed uniformly over the disk.
During hover; ~ One disadvantage may be the reduction in the Figure of Merit; particularly when considering that Dr. Gordon Leishman has said;- "... it had taken the industry sixty years to realize a helicopter with an average increase in rotor hovering efficiency (figure of merit or FM) of only 13%".
During cruise; ~ Another disadvantage may be the reduced Lift/Drag Ratio. In addition, the aft-located propeller (pusher configuration) will probably strip away some of the lift that is generated by the coaxial rotors. Consider the remark by Carson "...on average, the maximum L/D of the helicopter has only increased by less than 10% in the last 30 or more years."
If the above concerns are valid, can the X2 be a viable contender in the field of VTOL craft?
Dave
_________________________________
Bravo73,
The earlier XH-59A ABC had a two-speed transmission. To my recollection, a variable speed transmission for the X2 has been inferred but never stated outright.
The earlier XH-59A ABC had a two-speed transmission.
Some might suggest that most of the development should take place after the craft meets the notepad, not after it meets the helipad.
I thought it was a neat picture in that article that Lupin III linked to:
"...on average, the maximum L/D of the helicopter has only increased by less than 10% in the last 30 or more years."
-- IFMU
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IFMU,
How dare you suggest that Sikorsky is "doing some funny ..... thing"s.
Is this another funny thing?
Dave
How dare you suggest that Sikorsky is "doing some funny ..... thing"s.
Is this another funny thing?
Dave
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Dave, that's an interesting movie.
http://en.wikipedia.org/wiki/Flettner_Fl_185
Re inverse taper that is just the price paid for increasing the cruise speed. Future technologies could include independant root and tip control, but best to get the concept flying reliably first. I think Nick's comments were more to with the fact that on any project 90% of the development happens as the prototype reveals the machines characteristics - you get what you can right before hand, but simulation doesn't always capture everything.
http://en.wikipedia.org/wiki/Flettner_Fl_185
Re inverse taper that is just the price paid for increasing the cruise speed. Future technologies could include independant root and tip control, but best to get the concept flying reliably first. I think Nick's comments were more to with the fact that on any project 90% of the development happens as the prototype reveals the machines characteristics - you get what you can right before hand, but simulation doesn't always capture everything.
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With Catia V5R? being the main cad package, i'm guessing Abaqus CAE for the FEA?
Best of luck that strain guages don't reveal any unexpected loads - it is not often the case.
Best of luck that strain guages don't reveal any unexpected loads - it is not often the case.
Last edited by Graviman; 27th May 2008 at 11:56. Reason: Shows how out of date i am - i last used V5R5!
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Mart & CEFOSKEY,
Perhaps we have differing perspectives as to the meaning of '90% of helicopter development'.
IMHO, development is all inclusive; from the initial product conceptualization on through to the start of production.
What is done once the prototype is built and outside the barn door (flight testing, etc.) consists of refinements to the engineering that was previously done inside the barn.
Dave
PS.
The X2 ain't bilaterally symmetrical.
The engine is on the port side and the propeller's drive-shaft is on the starboard side.
But, since it's on the inside and doesn't affect aerodynamics ......
Many years ago Nick mentioned that Sikorsky does 90% of its helicopter development after the prototype has been built and is in testing.
IMHO, development is all inclusive; from the initial product conceptualization on through to the start of production.
What is done once the prototype is built and outside the barn door (flight testing, etc.) consists of refinements to the engineering that was previously done inside the barn.
Dave
PS.
The X2 ain't bilaterally symmetrical.
The engine is on the port side and the propeller's drive-shaft is on the starboard side.
But, since it's on the inside and doesn't affect aerodynamics ......