Northrop N333/N336/N340 Dorsal inlet fighters - ATS / ATF / VATOL

[flateric]

several pics of Northrop 1978 strike aircraft (refered also as VATOL and Air-To-Surface Advanced Tactical Fighter Aircraft) with dorsal inlets (may be that one El was talking about)

 

[flateric]

Northrop 1978 'Advanced Tactical Fighter Candidate Aircraft'
Again, remember that term ATF in 1978 meant a little bit different that it was in '81 or '85.

 

[overscan (PaulMM)]

Indeed - early studies focussed on air-to-ground, like the study just posted.

 

[elmayerle]

Northrop 1978 'Advanced Tactical Fighter Candidate Aircraft'
Again, remember that term ATF in 1978 meant a little bit different that it was in '81 or '85.

What's interesting about these is that it shows a concept Northrop originated, proved in the wind tunnel, but which hasn't shown up, as far as I know, in Real World designs. I refer to the use of dorsal inlets with a careful tailoring of the airframe in front of them to ensure good airflow even at high AOA. To the best of my knowledge, no company besides Northrop ever looked intently at this concept.

 

[overscan (PaulMM)]

Saab did a lot of work on a dorsal inlet configuration in the Saab JAS-39 Gripen program, but it was felt to be too risky.

 

[TinWing]

Saab did a lot of work on a dorsal inlet configuration in the Saab JAS-39 Gripen program, but it was felt to be too risky.

A dorsal inlet works well if you locate it in roughly the same vicinity as the cockpit of a manned aircraft.

If anyone doesn't care to believe me, I would refer them to the design of nearly every current UCAV demonstrator.

 

[elmayerle]

Saab did a lot of work on a dorsal inlet configuration in the Saab JAS-39 Gripen program, but it was felt to be too risky.

Northrop did a lot of studying on dorsal inlets, including tunnel time, and did find a way to make aft-plaeced dorsal inlets quite efficient even at high angles of attack. I remember seeing the papers in the AIAA Journal of Aeronautics back in the late 70s/early 80s; then all references disappeared. It does make you wonder.

 

[overscan (PaulMM)]

The Saab design had good high AOA performance too. The main objections were difficulty of placing a second seat without disrupting airflow into the inlet, and possible problems with combined high AOA and yaw.

 

[Sentinel Chicken]

Saab did a lot of work on a dorsal inlet configuration in the Saab JAS-39 Gripen program, but it was felt to be too risky.

Northrop did a lot of studying on dorsal inlets, including tunnel time, and did find a way to make aft-plaeced dorsal inlets quite efficient even at high angles of attack. I remember seeing the papers in the AIAA Journal of Aeronautics back in the late 70s/early 80s; then all references disappeared. It does make you wonder.

Considering the dorsal inlets offer advantages in lowering the overall RCS of an aircraft, it's likely that that work had enough of an impact on stealth aircraft design they got sucked into the "black world".......

 

[flateric]

more VATOL/HOTOL stuff

 

[overscan (PaulMM)]

Picture via forum member elider.

Looks like a colour version of the "ATS" design picture from the last page with dorsal intakes, possibly from AWST.

 

[overscan (PaulMM)]

Another pic of the dorsal inlet VATOL Northrop design, 1981 AIAA paper.


[Removed - better copy below - Admin]

 

[overscan (PaulMM)]

Northrop VATOL design

Northrop NASA Contractor's Report:

STUDY OF AERODYNAMIC TECHNOLOGY FOR VSTOL FIGHTER/ATTACK AIRCRAFT - VERTICAL ATTITUDE CONCEPT
H. A. Gerhardt, W. S. Chen
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19790001855_1979001855.pdf

 

[overscan (PaulMM)]

more, also from above plus

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19840014468_1984014468.pdf

 

[overscan (PaulMM)]

Better copy of this pic

 

[hesham]

Inlet and Airframe Compatibility for a V/STOL Fighter/Attack Aircraft with Top-Mounted Inlets
D. A. Durston and D. B. Smeltzer

inlet and airframe compatibility for a v/stol fighter/attack aircraft with top-mounted inlets - NASA Technical Reports Server (NTRS)

Aerodynamic force and inlet pressure data are obtained for 9.5% force and pressure models of a V/STOL fighter/attack aircraft configuration with top mounted twin inlets. Data are presented from tests conducted in the Ames Unitary Wind Tunnels at Mach numbers of 0.6, 0.9, and 1.2 at angles of...

ntrs.nasa.gov

 

[hesham]

Hi,

Top-Mounted Inlet Performance for a V/STOL Fighter/Attack Aircraft Configuration
Donald B. Smeltzer

top-mounted inlet performance for a v/stol fighter/attack aircraft configuration - NASA Technical Reports Server (NTRS)

Inlet flow-field and compressor-face performance data were obtained for a 0.095-scale model of vertical/short take-off landing (V/STOL) fighter/attack aircraft configuration with twin top-mounted inlets. Tests were conducted at Mach numbers from 0.6 to 2.0 and angles of attack and sideslip up to...

ntrs.nasa.gov

 

[Sundog]

Flateric, I was wondering if the report you were able to get the line drawings of the ATS design from, as shown on page two of this thread, had any info on it's dimensions or performance figures or if it was just a generic report?

 

[flateric]

check your mail

 

[Sundog]

Thanks!

 

[Sundog]

Top Mounted Inlet System Feasibility for Transonic-Supersonic Fighter Aircraft
T. L. Williams, W. P. Nelms and D. Smeltzer

top-mounted inlet system feasibility for transonic-supersonic fighter aircraft - NASA Technical Reports Server (NTRS)

The more salient findings are presented of recent top inlet performance evaluations aimed at assessing the feasibility of top-mounted inlet systems for transonic-supersonic fighter aircraft applications. Top inlet flow field and engine-inlet performance test data show the influence of key...

ntrs.nasa.gov

 

[overscan (PaulMM)]

Consolidating posts into a topic. Note - some of the later NASA studies appear to be NASA only tests repurposing the existing VATOL model to investigate top mounted inlets so aren't necessarily "Northrop" any more.

 

[overscan (PaulMM)]

Found on hard drive - source unknown. Was terribly scanned, have done some filtering in GIMP to save the image.

 

[overscan (PaulMM)]

Courtesy BillRo. Note twin vertical tails.

 

[Sundog]

Wow, love the Hatol version. Note, it also has a two man crew and what appears to be 2D nozzles.

 

[overscan (PaulMM)]

Actually I think it may be VATOL (wrong labelling on my part).

 

[Stargazer]

Found on hard drive - source unknown. Was terribly scanned, have done some filtering in GIMP to save the image.

BillRo posted elsewhere the model in the attached picture below as being POSSIBLY an "N-344".
However it seems to me like the exact same proposal. What do others think?
If it's the case, then the design is the N-338-12, as clearly stated on the tail fin in the above artwork (see detail attached).
I suspect "N-338" applied to the whole VATOL project.

 

[Sundog]

The picture of the model is the ATS, which isn't the same as the VATOL. It's similar because it was developed in the about the same time frame and I think the ATS design may have actually pre-dated the VATOL design.

 

[BillRo]

The reason I said "possibly N344" is because on the original 8X10 I can almost read the placard on the model stand. Actually N344-14 and the -14 is readable but it could be N 338-14, a minor variation. Pic is from 1982.

 

[BillRo]

As a point of interest I was responsible for the book listing the N3XX project #s for a few years. The numbers were issued for unique designs. If a project (say VATOL) needed more than one unique configuration they would receive different numbers. As they evolved and developed they would get a new -# for significant changes as long as they were basically the same design. For instance a two-place version would be a different -# or two tails vs one would warrant a new -#. Wish I had made a copy for history - it went back a few years.

 

[Stargazer]

The picture of the model is the ATS, which isn't the same as the VATOL. It's similar because it was developed in the about the same time frame and I think the ATS design may have actually pre-dated the VATOL design.

What exactly makes you say that "ATS" and "VATOL" refer to different projects? I have seen nothing in this topic to that effect.
To me, "ATS" may be the name of that particular Navy program, while VATOL just describes a general configuration (like VTOL, VSTOL, CTOL, etc.).

 

[Sundog]

The picture of the model is the ATS, which isn't the same as the VATOL. It's similar because it was developed in the about the same time frame and I think the ATS design may have actually pre-dated the VATOL design.

What exactly makes you say that "ATS" and "VATOL" refer to different projects? I have seen nothing in this topic to that effect.
To me, "ATS" may be the name of that particular Navy program, while VATOL just describes a general configuration (like VTOL, VSTOL, CTOL, etc.).

They do have similar inlets/propulsion system layouts, but the wing/strake designs are a very different and the ATS has the horizontal tail. I'm not saying they're unrelated, but the differences to me seem large enough that it would warrant a different model number and not just a different dash number.

Of course, I base that on the model pic and the artists renderings we have posted here at the forums and the fact that the ATS was for the USAF, not the Navy. If we ever see good drawings for it, then we should be able to tell a lot, but those would probably have the model number on them anyway. I guess we can hope that maybe Bill knows someone who has a copy of the model number book, besides N-G. Although, I think I'm experiencing sensory overload from everything Bill has posted over these past couple of weeks. I'm still pinching myself.

 

[boxkite]

Found on hard drive - source unknown. Was terribly scanned, have done some filtering in GIMP to save the image.

Interestingly, this illustration was published in West German magazine FLUG REVUE 3/1981 (p90) too. The artist is Harlan Krug - name sounds German ??? .

 

[overscan (PaulMM)]

The drawing in

Study of aerodynamic technology for VSTOL fighter/attack aircraft: Vertical attitude concept - NASA Technical Reports Server (NTRS)

The aerodynamic technology for a vertical attitude VSTOL (VATOL) supersonic fighter/attack aircraft was studied. The selected configuration features a tailless clipped delta wing with leading-edge extension (LEX), maneuvering flaps, top-side inlet, twin dry engines and vectoring nozzles. A...

ntrs.nasa.gov

ppears to show the VATOL design to be N336-12.


They are two different designs as Sundog notes. ATS was an Air Force program focused on Air-To-Surface roles, while the VATOL was designed to a Navy requirement for vertical takeoff. Clearly they share many features which is why they are one topic, but they aren't identical.

 

[overscan (PaulMM)]

Inboard profile from same PDF appears to depict N336-7

 

[overscan (PaulMM)]

Interestingly the PDF includes references to model tests of an earlier advanced fighter configuration:

7. Kantos, E. G., "Data Report of a 2.7 percent Scale Advanced Fighter Configuration Transonic Wind Tunnel Test", NAL-171 (NOR 77-037), February 1977.

8. Dawson, R. A. , "Data Report of a 2.7 percent Scale Advanced Fighter Configuration Transonic Wind Tunnel Test, Second Entry", NAL-180 (NOR 77-52), April 1977.

9. Franco, B. G. and Kontos, E. G., "Data Report of a 2.7 percent Scale Advanced Fighter Configuration Subsonic Wind Tunnel Test, First Entry", NAL-192 (NOR 77-108), July 1977.

10. Franco, B. G., "Data Report of a 10 percent N340 Fighter Configuration, Subsonic Wind Tunnel Test, First Entry", NAL-204 (NOR 77-141), December 1977.

If BillRo could scan the relevant original photo it will probably be possible to see if its N340.

 

[Stargazer]

Thanks for the help, Paul.

As for Harlan Krug, a quick web search produced a Northrop F-5 painting from 1971, which could indicate that he was an inhouse illustrator for that company in the 1970s.

 

[overscan (PaulMM)]

Thanks for the help, Paul.

As for Harlan Krug, a quick web search produced a Northrop F-5 painting from 1971, which could indicate that he was an inhouse illustrator for that company in the 1970s.

Even better link which appears to confirm he was a Northrop house artist:




http://www.ebay.com/itm/F-5-A-C-VINTAGE-60s-PHOTO-FROM-PAINTING-OF-HARLAN-KRUG-100-NORTHROP-ORIGINAL-/190685988030?pt=LH_DefaultDomain_0&hash=item2c65c544be#ht_500wt_1413

 

[BillRo]

Harlan Krug was I think the head graphics artist and often his paintings were signed. I have an original signed watercolor of the F-18L. Among the other artists was Bob Peck and you can recognize his work by the "impressionist" style with the splashes of color. Their work was not usually signed unless it was a big high quality painting like that F-5E for sale.
I don't believe I have a print of Tom Wier's Navy design shown above.

 

[Stargazer]

A slightly different version of the ATS picture shown in this topic's second post: