Grumman FSW X-29 (G-712) and its rivals

Ah! So now I realized what it was all about...
 

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A great thread with plenty of really nice images... but the subject of FSW and whether the program was successful or not has not been discussed here. I seem to recall that the X-29 program was found extremely satisfying on the whole. If that is the case, why didn't we see an operational application of FSW in a production aircraft after that? Was it merely a "proof-of-concept" program to show the concept was feasible, with no real intention to apply it operationally, or was it decided that the gains didn't outweigh the drawbacks? I'd like to hear more on the subject, especially when I see such beauties as this imaginary production model of the X-29...
 
It was not that satisfying. If I remember correctly, the biggest /unsolved/ problems were the vibrations and the warping of the wing tips, especially during the higher speeds. This caused the very high structural stress, what is nothing you want to hear when considering the battle damage resistance.
 
Here's my humble contribution to the very successful X-29 flight test program prior to the add-on flight tests. It was published in the fall of 1990. McGraw-Hill later procured Aero and TAB Books which destroyed the Aero book series - The X-29s completed a total of 422 test flights without a major mishap - 242 by No. 1, 180 by No. 2



Steve Pace
 

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Here's my humble contribution to the very successful X-29 flight test program prior to the add-on flight tests

Steve, I've got a copy in my library :)
 
Stargazer2006 said:
was it decided that the gains didn't outweigh the drawbacks? I'd like to hear more on the subject, especially when I see such beauties as this imaginary production model of the X-29...

IIRC, the transonic performance was improved but at higher speeds the trend was reversed (compared to conventionally swept wings). Anyone can confirm/deny? Or more simplistically, the actual implementation of new technologies sometime depend more on the strength of their proponents rather than their technical merits. Maybe the people in a position to make decisions were not supporters?
 
X-29A No. 1 hit 1.48 Mach number - not bad for a wing that was supposed to rip off at such speed. -SP
 
FSW usually requires a nice leading edge/fuselage fillet to avoid separation problems, so you have some sort of backsweep near the fuselage. I guess you can try to align it with the trailing edge of the opposite wing, but i don't think the end result is as good as having just two edges facing forward as in a conventional backswept configuration. In fact you could end up with a corner reflector!
 
IIRC, the transonic performance was improved but at higher speeds the trend was reversed (compared to conventionally swept wings). Anyone can confirm/deny?
Based on what I know about area-ruling, that could well be the case. If the largest "bulge" in volume distribution is often caused by the wings, then a forward-swept wing aircraft will likely have the bulge closer to the front of the aircraft than in a rearward-swept wing. As mach numbers increase, the ideal shape for reducing wave drag requires a bulge that is closer to the rear. This would make the rearward-swept wing closer to the desired volume distribution and thus have lower wave drag. This would probably be especially true with delta wings.
 
An illustration of the Rockwell Sabrebat not seen before in this gallery, and another two which were already posted (in smaller size) on page 1, all taken from Daniel P. Raymer's indispensable book: Aircraft Design - A Conceptual Approach, published in 1992 by AIAA.

[Edit - better copies posted later in topic - Admin]
 

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Above M=1.7 the structural weight penalty is too great for it to be competitive with conventionally swept wings. It just becomes too heavy. Plus, there are limitations with regard to weapons load out.
 
As a general note, area ruling is usually targeted to one flight regime, that is, there is one area distribution that minimizes wave drag at M=1.0 and that is different from that which minimizes drag at M=1.2 or M=1.4.
It used to be that you aimed for min drag at M=1.0 because that's where engine thrust minus airframe drag created a pinch and made acceleration slow, but today's engines have enough thrust to push through that regime and designers optimize the cross sections for higher Mach numbers. I'm pretty sure supercruisers are not optimized for M=1.0.
 
Early artist's impression of X-29, from AvWeek.
 

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Great stuff! It's nice to be scanning those old AW&ST issues. Just one little thing: don't forget to include the date of the article, it really helps!
 
Right! I kept the paper copy, so I should be able to date it more precisely when i get back to my office. For now suffice to say it's between '79 and '81. ;)
 
flateric said:
Genesis of X-29 - first scetch by Nathan Kirschbaum, also shown in artist's rendering here
http://www.secretprojects.co.uk/forum/index.php/topic,106.msg576.html#msg576

Note that this early proposal had the scarfed inlets, arranged to rotate 180 degrees, which can improve the airflow in different angles of attack.
 
Look this is gonna sound real lame, but in a dream I had last night, I spotted what looked like a FSW F/A-18 model on a shelf in a classroom.

When I got up, I still had the plane stuck in my head so I sketched a rough version as best I could. I'm gonna have to refine it as best I can seeing as I had no coffee in me yet when I drew it.

OK, so now the $20 million dollar question.................

Was there ever a FSW F/A-18? Even in just concept form?

I put the question here since we quite don't have an "F/A-18 Hornet projects" thread.

Enquiring minds wanna know!
 
XP67_Moonbat said:
Was there ever a FSW F/A-18? Even in just concept form?

I put the question here since we quite don't have an "F/A-18 Hornet projects" thread.

Enquiring minds wanna know!

I think the Japanese might have looked at one as part of this particular FSX design study:
index.php

Not a 100% sure though!

More on the FS-X studies here: http://www.secretprojects.co.uk/forum/index.php/topic,13112.0.html
 
After spending the last 25 years on exhibit at the Smithsonian National Air and Space Museum in Washington, D.C., the only full-scale mockup of the famed Grumman-built X-29 aircraft has come home to Long Island. Northrop Grumman Corporation (NYSE:NOC), who designed and built the revolutionary forward swept wing aircraft demonstrator, welcomed the aircraft yesterday to the Cradle of Aviation Museum in Garden City, N.Y.


Source: http://www.irconnect.com/noc/press/pages/news_releases.html?d=233186
 

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From http://www.spacewar.com/reports/Cradle_of_Aviation_Welcome_Home_X_29_Aircraft_999.html

Cradle of Aviation Welcome Home X-29 Aircraft

Cradle of Aviation Welcome Home X-29 Aircraft
by Staff Writers
Bethpage NY (SPX) Sep 26, 2011

Former X-29 aircraft program supporters and engineers reunited at the Cradle of Aviation Museum, Garden City, N.Y., to welcome back home a mock-up of the forward swept wing aircraft: (From left) Dick Dunne, formerly of Grumman Public Affairs; David Neyland, director, Tactical Technology Office, Defense Advanced Research Projects Agency; Michael Moore, engineer, Advanced Programs and Technology (AP and T), Northrop Grumman Aerospace Systems (NGAS); Glenn Spacht, former deputy director of Development on the X-29, and former vice president and chief engineer of Grumman Aerospace; Bob August, program manager, AP and T; Steve Hogan, vice president, Information Operations and Electronic Attack, NGAS; and Andy Parton, executive director, Cradle of Aviation Museum.
After spending the last 25 years on exhibit at the Smithsonian National Air and Space Museum in Washington, D.C., the only full-scale mockup of the famed Grumman-built X-29 aircraft has come home to Long Island. Northrop Grumman, who designed and built the revolutionary forward swept wing aircraft demonstrator, welcomed the aircraft yesterday to the Cradle of Aviation Museum in Garden City, N.Y.

A day-long series of special events were held at the museum for local area students, company employees, retirees and aviation enthusiasts, including a guided tour by Northrop Grumman engineers and a reunion dinner. The company funded the transportation costs for the X-29 with a $5,000 grant to the museum.

"We're honored to accept this incredible aircraft from the Smithsonian Air and Space Museum and add it to our vast collection," said Todd Richman, chairman of the board of the Cradle of Aviation Museum. "We owe Pat McMahon and Northrop Grumman a small debt of gratitude for bringing the X-29 home where it belongs. I hope it amazed our students yesterday and inspires countless generations to come."

A panel discussion was held during the dinner featuring X-29 Program Manager Glenn Spacht, who was also vice president of engineering for Grumman Aerospace at the time of the X-29 program. Joining him was Bob August, manager, Advanced Programs and Technology Division, Northrop Grumman Aerospace Systems. August worked on the program immediately following graduation from college.

"Having the X-29 here at the Cradle of Aviation Museum will allow students to learn from the success of this demonstration plane. It will also give them a chance to imagine what the human mind can create next," said Steve Hogan, vice president, information operations and electronic attack, Northrop Grumman Aerospace Systems.

"Whether it is a manned or unmanned aircraft, or other advanced capability we are developing and delivering to our customers, there is nothing more important than demonstrating the value of performance every day to America's troops," he added.

Hogan also introduced the special guest of the evening, David Neyland, director of the Tactical Technology Office at DARPA, the principal agency within the Department of Defense for advanced research and development. DARPA was the original sponsor and a key motivator for the development of the X-29 and its associated flight research program.

"There's a lot of things associated with this airplane that inspired us as a nation in technology and innovation to keep ahead of the other guys. It was the first of its kind in terms of extreme margins of instability on the airplane--instability meaning the aircraft doesn't want to fly in a straight forward direction," Neyland said.

"Now, it's about who builds the next X-29, who builds the next lunar module... There's a real important mission here that I can't understate and that is the 'inspiration' coming from a new generation that's looking forward."

Yesterday, students from Uniondale High School, who are part of the Cradle of Aviation's Science, Technology, Engineering and Math (STEM) Magnet Academy, were some of the first to view the X-29 at the museum. Michael Moore, a Northrop Grumman engineer, who also worked on the X-29 program, guided the tour.

"I'm honored to have had the opportunity to work on the X-29 program and to have had such a terrific career at Northrop Grumman," said Moore. "Every day we are advancing the next generation of technology and that is very exciting. Hopefully I have made the students feel energized about their future potential."

Northrop Grumman supports dozens of programs to foster and expand educational opportunity at all levels. The company, in partnership with the Northrop Grumman Foundation, endorses programs to inspire and encourage student interest in STEM disciplines, funding educational opportunities for students and teachers.
 
I recently worked with a guy who was a test pilot on that program. He had some interesting things to say about it. Unfortunately, I am hazy on the details, but the gist of it was that people think of the X-29 as a failure because it did not lead to FSW on American combat aircraft. But he said that the view of everybody on the program was that it was actually a success because it really defined what FSW could and could not do, removing a lot of uncertainty and allowing aircraft designers to decide whether or not to use it. It also provided a lot of useful aeronautical data.
 
A DoD artist sketch pf the Rockwell Sabrebat, found on page 26 in the book "An Illustrated Guide to NATO Fighters and Attack Aircraft" by Bill Guston, Salamander Books 1983.
 

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Two more pics of the Rockwell Saberbat mockup from Paris '79, from Italian magazine Aerei (September 1979 issue) B)
 

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If the initials of my name are FSW does that mean it was my destiny to be fascinated by FSW aircraft?

later,
Forrest
 
southwestforests said:
If the initials of my name are FSW does that mean it was my destiny to be fascinated by FSW aircraft?

later,
Forrest

Hi Forrest, and welcome! Don't know about "FSW"... Did you sleep with your arms extended forward as a kid? That might be some sort of indication... ;D
And what of people called, say, "Scott Thomas Digby" or "Sean Tyrone Driggs"?!? Do they have a natural leaning towards venereal diseases? ::)
 
[Images from Darold Cummings via Aerofranz in this topic - Admin]
These had nasty Moire effect. This is my quick attempt at restoration. Thanks - excellent info which makes sense of the design history.
 

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X-29 inboard profile (Grumman document):
 

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Steve Pace said:
anybody ever read my x-29 book - sp

I have, Mr. Pace. But it was some time ago. I do still have it stashed away somewhere. I do recall enjoying it. This is the book in question in case anyone is interested in tracking it down:
ISBN: 0830634983
 

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I, too, have a copy. It is a very pleasing & thorough coverage, Mr Pace.
 

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