Northrop Grumman Supersonic Tailless Air Vehicle (STAV) concept

[flateric]

http://www.va.afrl.af.mil/success_stories/pdf/STAV%20testing%20%20VA-S-07-08.pdf

AFRL Assists Northrop Grumman With Supersonic Tailless Air Vehicle Tests
AFRL provided a full-motion flight simulation environment to test candidate control systems for Northrop Grumman’s Supersonic Tailless Air Vehicle (STAV) concept. The testing, conducted in the lab’s Large-Amplitude Multimode Aerospace Research Simulator (LAMARS), incorporated design improvements based on new wind tunnel data and reflecting two additional controllers, ground effects, and modified landing gear.
Throughout the testing, three Northrop Grumman test pilots evaluated aircraft performance during takeoff, landing, and subsonic and supersonic tracking tasks. The pilots used the Cooper-Harper rating scale, a method that assigns quantitative scores according to desired and adequate performance criteria, to evaluate aircraft handling qualities. Compared to the results of earlier tests performed in May 2006, the aircraft’s tracking and landing tasks received significantly higher ratings, due primarily to the incorporated design modifications. The study allowed Northrop Grumman engineers to collect data on over 100 different parameters throughout more than 300 tests runs. They were also able to observe the effects of auto-throttle on the STAV concept. This evaluation and data collection effort will facilitate further improvements to the concept. Once Northrop Grumman has incorporated the necessary design modifications, the research team plans to return to AFRL’s LAMARS facility for additional testing.
The STAV concept entails an effort to reduce the weight and drag encountered in traditional supersonic aircraft designs. This reduction is achievable by eliminating the tail and replacing conventional tail control surfaces with more innovative control effectors.

VERY interesting person involved in STAV:

Steven C. Komadina
Northrop Grumman Corporation
Education:
B.S. Aerospace Engineering, Arizona State University, 1980
After graduating from Arizona State University, Mr. Komadina started work at Northrop’s Aircraft Division in Hawthorne, CA and has remained at the company his entire career. He was initially assigned to the Advanced Design department and worked on competitive aircraft assessment. He was later assigned to the Advanced Projects organization where he worked in the aero-performance department and supported the Defense Advanced Research Project Agency (DARPA) TACIT BLUE stealth demonstrator program and the Air Force Advanced Technology Bomber (ATB) proposal effort; which turned into the B-2 program. He supported the TACIT BLUE program through completion of flight testing and follow-on operational vehicle studies. Mr. Komadina then worked on the Northrop Advanced Tactical Aircraft (ATA) internal research and development (R&D) studies and the following Navy ATA competition where he was the lead vehicle performance engineer and later the lead aerodynamic design engineer. After that he worked on an advanced technology demonstrator competition and led the aerodynamic design, analysis, and test activities(-sic!). Mr. Komadina then for several years led all of the flight sciences activities for an advanced transport technology program, many internal technology R&D programs, and the Unmanned Combat Air Vehicle (UCAV) program. He then became the Air Vehicle integrated product team (IPT) lead for the Future Strike Systems business area, and in parallel was the Chief Engineer on the DARPA Quiet Supersonic Platform (QSP) program. He became the functional manager for the Adv. Flight Sciences & Weapons Integration department in 2004. Most recently he was the Chief Engineer on the DARPA Oblique Flying Wing proposal and program through Milestone 1 and program manager on three technology R&D contracts related to next generation long range strike supersonic tailless air vehicles. Mr. Komadina is also the program manager for the Aerodynamic Efficiency Improvement program that is investigating aeroservoelastics, gust load alleviation and swept wing laminar flow control related to next-generation high altitude intelligence, surveillance, and reconnaissance (ISR) platforms.

 

[flateric]

http://stinet.dtic.mil/cgi-bin/GetTRDoc?AD=A482575&Location=U2&doc=GetTRDoc.pdf

Limited Evaluation of Handling Qualities for a Supersonic Tailless Air Vehicle (Project HAVE STAV)
Authors: Steven W. Speares; Nathan L. Cook; Matthew R. Domsalla; Jason B. Porter; James W. Quashnock; Brian J. Neff; TEST WING ( 412TH) EDWARDS AFB CA

Abstract: This report presents the results of Project HAVE STAV, a limited evaluation of the handling qualities for a Supersonic Tailless Air Vehicle (STAV). This test program used the Calspan-operated Total In-Flight Simulator to test the powered approach handling qualities of a Northrop Grumman STAV model. The test team developed an optimized control system prior to flight testing. The handling qualities were determined using the STAV model coupled with either the baseline or optimized control system. The USAF Test Pilot School, Class 07A, conducted six flight test sorties totaling ten hours at Niagara Falls International Airport, New York, from 10 to 13 Sep 2007. Flight testing included a series of precision and lateral offset landing tasks, which were accomplished at different crosswind conditions. All test objectives were met.

Limitations: APPROVED FOR PUBLIC RELEASE
Description: Final technical information memorandum, 10-13 Sep 2007
Pages: 80
Report Date: DEC 2007
Report Number: A575284

 

[fightingirish]

Supersonic and Tailless - the Next Step in Stealth?
Posted by Graham Warwick at 1/12/2009 1:59 PM CST @ Aviation Week.com

 

[flateric]

Team provides specialized techniques to test aircraft

by Philip Lorenz III
AEDC/PA

5/16/2008 - ARNOLD AIR FORCE BASE, Tenn. -- A team at Arnold Engineering Development Center (AEDC) recently conducted aerodynamic testing, using a combination of more conventional methods and the application of pressure sensitive paint (PSP) on a scale-model of a tailless aircraft for the Air Force Research Laboratory in the center's four-foot transonic wind tunnel.

The test article represented a supersonic research aircraft that employed a jet effects
opening or slot on the top of one wing and a solid spoiler on the other wing to compare
the effectiveness of each in providing yaw and roll control for stability in fl ight, said Brant Maines, the Lockheed Martin Corp. program manager on the test.

"The main objective of the test program was to develop an aerodynamic database that we could use to validate our computational predictions of virtual fluidic surfaces - it's kind of what we call them - essentially fl uidic spoilers, jet spoilers and other similar applications," he explained. "We ran steady air at different locations and with different jet exit geometries on the model. We were able to measure forces and moments and take a lot of pressure sensitive paint data in order to get pressure distributions that we could then compare directly to the computational predictions."

Maines said the use of PSP was of particular value in acquiring high quality data they needed from the test. PSP is a technique that uses a special paint and illumination source combined with an extremely sensitive camera to obtain surface pressure data.

The paint is applied to the model in two layers, a white undercoat and the PSP layer. The white undercoat provides a uniform refl ective surface for the PSP layer. The illumination source excites the PSP layer, which fl uoresces with intensity inversely proportional to the surface pressure on the model.

"Pressure sensitive paint gives us a near real-time visualization of the entire pressure
distribution over the upper surface of the wing," he said. "So, instead of having the individual pressure taps sporadically placed on the surface, we get a complete
picture that then is very easily compared to the computational fluid dynamics (CFD) estimates and simulations that we performed on the model.

A spoiler, whether it's a metal plate or pressurized air from an opening in the upper surface of a wing, reduces lift and increases drag. Creation of these aerodynamic
forces can then be used to control the vehicle in flight..

Judy Bergmann, the center's ATA project manager on the entry, said the test was a technology demonstration of jet effects on a one-eighteenth scale model of an Air Force conceptual aircraft. She said the aircraft itself was not the focus of the test, but rather the data gleaned from using the unconventional routing of air over the aircraft to control it.

"We supplemented force and moment data with the information we could get by applying PSP," explained Marvin Sellers, the ATA engineer who has the most experience with PSP at AEDC. "We were really only interested in the top surface of the model and seeing what happens to the pressure distribution from the jet, and compare that to their computational fl uid dynamics solutions. So, the PSP was a tie-in to the CFD so they could see the distribution of the pressure on the model. The balance was the primary measurement of the effectiveness of the jet or pitch, yaw, roll control."

Sellers and Bergmann said the customer's representatives were analyzing the data while they were at AEDC and saw some unexpected things as well as some anticipated results.

"When we started putting pressurized gas out of the jet they expected the rolling moment to go one direction, and it actually went the opposite direction," Bergmann explained. "They were not sure why that was happening, but they were able to look at the PSP
and see pressure distributions on the wing that would back up what the balance was measuring. They could see what was going on and what processes were happening
around the jet to cause that. That helped them understand that issue. That's the reason you test."

Sellers pointed out that the test provided a fi rst look at the aerodynamic interactions between the airflow from the jet and around and over the aircraft model.

"It was all preliminary; an initial study of the jet," he said. "It gives them a little bit of an
understanding on what's happening so they can decide what to do in the future."

The customers were not the only ones who were venturing into some new territory.

"Probably the biggest challenge we had, from my viewpoint, was the air system setup
our team did," Bergmann said. "Reggie Riddle, Dave Beard and Marvin Sellers did a tremendous amount of work on getting that system in place because there isn't a
standard system like that in 4T.

"They used things from the 16-foot transonic wind tunnel system that we brought in, including one trailer full of high pressure air and another one full of high pressure helium to provide the gases."

She said two different gases were used to simulate jet exhaust.

"Air is easy to use for simulation of jet exhaust, but it doesn't match the true characteristics, the properties of the high temperature gases that might actually be used to do this," she explained. "High pressure helium simulates that better than air.

"They call it the maximum flux - this is what they were trying to match - the max flux which deals with temperature density and pressure and gas properties. You can either raise the temperature of the gas to make it match the mass of the true gas or you can knock the density down which should also simulate jet exhaust gases more closely. So, that's what the helium is for. And the helium actually provided better results, closer to what they expected."

Photo: A one-eighteenth scale model of an Air Force tailless aircraft underwent aerodynamic testing in Arnold Engineering Development Center's four-foot transonic wind tunnel. The test was a technology demonstration entry in which conventional methods and Pressure Sensitive Paint were used to compare the effectiveness of a jet effects spoiler with a solid spoiler in yaw and roll control and stability of the aircraft. (Photo by Rick Goodfriend)

 

[sferrin]

Looks like this Lockheed design sort of.

 

[flateric]

yep, agreed for 100%. and last beast (tested in AEDC) trailing edge looks similar to much earlier Lockheed's FATE/ICE concept.
so seems we have NG and LM STAV candidates here

 

[Sundog]

Any idea what the bumps are on the under surface of the wing?

 

[quellish]

Any idea what the bumps are on the under surface of the wing?

http://www.google.com/patents/about?id=3xOwAAAAEBAJ

Almost certainly control effectors, though they could very well be something else:
http://www.freepatentsonline.com/EP1926353.html
NG has been active with this technology for a lot longer than LM has. Apparently LM thinks it would be an enabler for a supersonic long range strike vehicle.

 

[Sundog]

Yeah, I thought they might be some kind of control effector, they just looked somewhat large and "draggy." As for the second patent you reference above, way back in the 80's, one of the guys who lived on my floor was developing that technology, or something similar, while he was a grad student. IIRC, he was a co-op student with the CIA at the time. Whether or not it related to his work there, though, I haven't any idea.

 

[elmayerle]

Any idea what the bumps are on the under surface of the wing?

http://www.google.com/patents/about?id=3xOwAAAAEBAJ

Almost certainly control effectors, though they could very well be something else:
http://www.freepatentsonline.com/EP1926353.html
NG has been active with this technology for a lot longer than LM has. Apparently LM thinks it would be an enabler for a supersonic long range strike vehicle.

NG has been active in a number of areas longer than LM, that's likely one reason tehy are partnered on more than just the JSF.

 

[Matej]

There is/was a high-res image on the http://www.wpafb.af.mil/news/story.asp?id=123055800 I cant open .mil URLs, so does anybody save this image?

 

[flateric]

you will be surprised, but there's the same small one under hi-res link
pocus I've learned the day they put STAV news there

If we could ask Bill or Graham or Steve for hi-res...

 

[Matej]

Found thanks to reverse image search engine TinEye.com But: Credit: NASA Lockheed Skunkworks ??

 

[flateric]

http://www.cecs.wright.edu/cepro/research/long-range-strike-aircraft.shtml

 

[XP67_Moonbat]

Great find!

 

[flateric]

www.dtic.mil/get-tr-doc/pdf?AD=ADA482575

 

[flateric]

seems that at some point STAV migrated to ESAV (Efficient Supersonic Air Vehicle) with AFRL, at least two major players and academic institutes participating in research

from 2012 AIAA paper

"The Ecient Supersonic Air Vehicle (ESAV) is a long range, highly survivable aircraft under development by the Air Force Research Laboratory along with academic and industry partners. The vehicle is to be designed to have a range of approximately 4000 nautical miles, a cruise Mach number greater than 2.0, and to carry payloads of approximately 20,000 lbs. Low observability (stealth) and drag reduction have motivated the development of the ESAV to focus on tailless planforms with embedded engines above the wing."​

Interesting that paper cited uses Boeing ULRSA (Unmanned LRSA) from ca.2004 as illustration of notional ESAV concept. But apart of NG and LM concepts mentioned above it clearly doesn't have engines above the wing.​

Another paper ressurection of Rapid Theater Attack idea?​

 

[Grey Havoc]

Another paper resurrection of Rapid Theater Attack idea?

Sub-strategic concepts do seem to be coming back into fashion.