The American Su-47, the X-29...

I have no idea whatsoever if this thing has been posted... But a friend of mine gave me a tip about a very interesting plane. It has the same characteristic as the Su-47 with forward-svept wings... Check this thread out...

The X-29 did it's first flight at NASA Ames-Dryden Flight Research Facility in May 23, 1989. The plane had a very interesting design, and was therefore meant for investigations of "advanced concepts of technologies" as NASA explains it. The program was conducted during 1984 to 1992.

The plane was 48.1 feet long and its wing span was 27.1 feet. Each plane had General Electric F404-GE-400 engine producing 16,000 pounds of thrust. Empty weight was 13,600 pounds, while takeoff weight was 17,600 pounds. The plane was capable of rising up to 50.000 feet, and its top-speed was 1.6 mach. It could fly about an hour with out refueling (you couldn't refuel it int he air :lol

As said, the X-29 had a very facinating design. It had forward-svept wings wich gave the plane superb manouverability but made the plane pretty unstabile. The tests clearly showed that the plane gave the pilot exellent control at 45 degrees angle of attack.

During its flight history the X-29 flew 422 (436) missions, 242 missions were conducted by the first test plane, and the rest by the second plane.

Reverse airflow-forward-swept wing vs aft swept wing. On the forward-swept wing, ailerons remained unstalled at high angles of attack because the air over the forward swept wing tended to flow inward toward the root of the wing rather than outward toward the wing tip as on an aft-swept wing. This provided better airflow over the ailerons and prevented stalling (loss of lift) at high angles of attack.

Apparently it wasn't so new after all with forward-svept wings. before world war 2 the Germans tested gliders with forward-swept wings. The Americans also conducted some tests at NACA Langley Memorial Aeronautical Laboratory in 1931. But it wasn't untill the composite materials came in the picture during the 1970. Because it had been impossible to make these kind of planes before without breaking the plane.

X-29 - designed with relaxed static stability to achieve less drag, more maneuverability, increased fuel efficiency. Arrows in upper illustration indicate drag-producing opposing downward forces on rear stabilizers to achieve stability. X-29 canards share lifting loads, reducing drag.

After all, the plane never became a great success, but it taught the Americas the simple basics of "forward-swept wings"

PICS!!!

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www.globalsecurity.org...
www.dfrc.nasa.gov...
www.globalaircraft.org...

[edit on 30-11-2005 by Figher Master FIN]

Here are some other ATS threads that make references to the forward swept wing X-29.
Also, check out the thread entitled Rockwell Saber Bat, it was a forward swept design prior to the X-29.

The Official Best Concept Planes Thread
What are advantages of Forward Swept Wings?
Questions about wing designs
Rockwell Saber Bat

The pehonominon that required the strength of composite matierla is called aeroelastic divergence if I recall correctly

Wing Divergence
Another problem of the wing is the critical wing divergence (e.g. the operation point at which irreversible aeroelastic effects take place, with catastrophic consequences). This difficulty would require a much heavier wing than the corresponding backward swept wing. The problem could be partially solved with the use of advanced composite materials.
aerodyn.org...

Originally posted by intelgurl
Here are some other ATS threads that make references to the forward swept wing X-29.
Also, check out the thread entitled Rockwell Saber Bat, it was a forward swept design prior to the X-29.

The Official Best Concept Planes Thread
What are advantages of Forward Swept Wings?
Questions about wing designs
Rockwell Saber Bat

Thanks... a very interesting plane...

What FredT is talking about is the fact that the wingtips of the X-29 twisted as it flew. The composite materials were strong enough to resist damage cused by this twisting, but until they came along, the wing had to be made heavier to withstand this problem. Since they used composites they were able to give it a supercritical wing, which made a big difference in performance.

Introduction of composite materials in the 1970s opened a new field of aircraft construction. It also made possible the construction of the X-29’s thin supercritical wing. State-of-the-art composites allowed aeroelastic tailoring which, in turn, allowed the wing some bending but limited twisting and eliminated structural divergence within the flight envelope (i.e. deformation of the wing or the wing breaking off in flight). Additionally, composite materials allowed the wing to be sufficiently rigid for safe flight without adding an unacceptable weight penalty.
www.dfrc.nasa.gov...

Just a little expansion on what FreT had so say for those that might not know what he meant.

Man I love the look of planes with FSWs I consider the SU-47 one of the best looking planes ever.

The X-Planes are indeed amazing, Im not positive but I think a X-plane was using vectored thrust before the Russians aswell.

Apart from the P.1127/Harrier family (which is a different kettle of fish altogether) I think the first plane to fly with TVC installed was the F-15 ACTIVE demonstrator, the X-31 followed but I'm not sure how it stands in relation to when the Russians first had such a plane flying.

Does anyone think the X-29 could have made a decent light fighter? How would those wings stand up on a service fighter?

On aeroelasticity...

There are two types of failure possible - 'in section' (2D longitudinal) and 'overall wing' (3D lateral), these aren't the proper technical terms... well, they might be, I just cant remember.

It occurs in every wing... to prevent it the shear centre (s.c) of the wing needs to be ahead of the aerodynamic centre (a.c) of the aerofoil section (2D). So when the wing generates a lift it will tend to twist back towards equilibrium - therefore divergence is impossible.

The 3D effect is similiar only its the position of the s.c of the inboard wing section relative to the outboard a.c. If the s.c. is ahead of the a.c the wing is stable (twists towards equilibrium) but for forward swept wings, this is impossible, so the wing is unstable.

There is a cross over effect of 2D and 3D, but its too complicated for me to bother thinking about right now

Composites allow tailoring in lay-up to produce stronger resistance upon these twists/loadings, effectively forcing stability through brute strength.

X-29 - designed with relaxed static stability to achieve less drag, more maneuverability, increased fuel efficiency. Arrows in upper illustration indicate drag-producing opposing downward forces on rear stabilizers to achieve stability. X-29 canards share lifting loads, reducing drag.

Considering drag reduction, I thought it was indeed designed for that and forward swept wings have the theoretical promise of drag reduction, but that his hasn't actually been achieved yet?

IIRC that was the reason they gave it a supercritical wing. But they couldn't do that until the composites came along.

The X-29 was derived from the F-20 program (F-5 single engine varient).
Don't forget the competitor to the X-29... the SFW/F-16.

The SFW/F-16 was rejected by DARPA in January 1981 in favor of the Grumman 712 (an F-5/F-20 derivative), later designated the X-29A. The decision was mainly a political one, as many thought that the test-scene at NASA was heavily dominated by General Dynamics' F-16s (AFTI, CCV, F-16XL). Another much-cited reason was that "One could only learn so much from a single airframe", though in retrospect, ongoing experiments with the F-16 seem to prove this wrong. It is interesting to note that the chosen design, the X-29A, consists for about 16% of F-16 components, including the Fly-By-Wire Flight Control System.

Originally posted by ShadowXIX
Man I love the look of planes with FSWs

I consider the SU-47 one of the best looking planes ever.

The X-Planes are indeed amazing, Im not positive but I think a X-plane was using vectored thrust before the Russians aswell.

believe your talking about the X-31. Here is a link to the some X-31 movies. It was a really neat airplane and I can't wait till i see some good footage of the F-22 using it thrust vectoring for some close combat manuveres. If anyone knows of some links to good F-22 footage letting me know would be great.
www.dfrc.nasa.gov...

[edit on 1-12-2005 by Canada_EH]

Originally posted by Canada_EH


believe your talking about the X-31.

Yup thats the one I remember when they first brought it to the Paris Airshow. Alot of people thought it was going to crash as it was doing some crazy post-stall maneuvers flying well beyond the aerodynamic limits of conventional aircraft

The F-15 ACTIVE also experimented with Thrust Vectoring at the Dryden Facility.

www.dfrc.nasa.gov...










I sure do love the F-15 series, beautiful birds they are.

Also, for a multi-purpose export, look into the MiG-29 OVT.

The MAKS-2005 Airshow featuring the new MiG-29 OVT(pics)

It's a nice looking plane definetly, and I'm sure it will perform superb once it hits the export market.

Shattered OUT...

Originally posted by waynos
Apart from the P.1127/Harrier family (which is a different kettle of fish altogether) I think the first plane to fly with TVC installed was the F-15 ACTIVE demonstrator, the X-31 followed but I'm not sure how it stands in relation to when the Russians first had such a plane flying.

Does anyone think the X-29 could have made a decent light fighter? How would those wings stand up on a service fighter?

Corect me if I'am wrong but it reminds me pretty much of the F-5... So I could defenetly see it as a nice fighter... Pity that it just goes 1.6 mach...

No you're not wrong FIN. The X-29 used the cockpit and nose of the F-5 mated to a new rear fuselage (not that of the F-20, it is only similar, not the same) plus the main undercarriage of the F-16

If I remember correctly the F-15 ACTIVE used conventional 'round' vector thrust and square vector propulsion just like the one on the Raptor.

It was the testbed for the low heat emision thrust.

I don't think I've ever seen the F-15 ACTIVE with round vectoring nozzles like the Russians use but it was modified to fly with 'square' F-22 type nozzles after its initial flight tests with normal engines.

Originally posted by carcharodon
If I remember correctly the F-15 ACTIVE used conventional 'round' vector thrust and square vector propulsion just like the one on the Raptor.

It was the testbed for the low heat emision thrust.

Advanced Controls Technology for Integrated Aircraft (ACTIVE).

Does low heat emission thrust fall into that category? I thought that the ACTIVE was the test bed for the application of Thrust Vectoring to aircraft, like how it would perform on existing airframes.

Wait, the F-15 ACTIVE came before the X-31? I guess it would make sense because the X-31 is 3 dimensional correct?

Shattered OUT...