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21 May 2006
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US Navy`s ‘Carrier-Based ASW Aircraft Experimental’ (VSX) Program

Although they are being phased out of service (long before their time!) the US Navy’s Lockheed S-3 Viking ASW aircraft was one of the most advanced and compact aircraft of its type and role ever built.

(Note- One must remember that LTV (Vought) had a lot to do with making the Viking what it was and so successful, with Lockheed sorting LTV`s input as prim contractor for its great knowledge and experience in designing carrier based aircraft)

But the Lockheed S-3 Viking’s history stemmed from a 1968 US Navy Request for Proposal (RfP) for an advanced Carrier-Based ASW aircraft Experimental (VSX).

But who knows of the other four designs that were submitted to the Request for Proposal, by-
• Grumman
• McDonnell Douglas
• General Dynamics (Model 21)
• North American – Rockwell

Does anyone have any information, design designations, pictures, artwork /drawings of the designs submitted

The Convair VSX contender is illustrated in:

Flight International 30 January 1969
and in
Aviation Week&Space Technology of December 9 1968.
(very much a Viking look-alike)
Here's the Convair VSX from the mentioned Aviation Week issue :


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Pardon the necromancy, but I have always been a bit confused concerning the Convair division after the merger with General Dynamics. Were they still a seperate aircraft designing entity from GD Fort Worth or is "Convair" just a vestigial name for the Fort Worth division?
In 1974, Convair (San Diego) and General Dynamics Fort Worth separately submitted design studies in support of the Navy's VFAX program. GD's was a derivative of the F-16.
The new issue of The Hook magazine -- the same issue w/the 'XF5V' posted elsewhere yesterday -- also has a retrospective on the S-3, and included is a small image of North American's entry in the VSX competition won by Lockheed's design. Thought I'd post it in case there's still interest. Has anyone found any info on the McDonnell entry?


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Convair had a couple of proposed ASW designs. I'd have to dig through my stuff to find them. However, around 1971 or so they proposed a tilt-wing aircraft for sub-hunting. Then they later proposed the aircraft above, which lost to the S-3.

The earlier aircraft was tied to the Navy's Sea Control Ship proposal. With a smaller deck and no catapults, a sub-hunting aircraft would need good STOL performance. Convair also envisioned this aircraft flying off of the CVS (sub-hunting) carriers, essentially replacing the S-2 Tracker. However, the CVS carriers started getting retired by the early 1970s, and the Navy was always ambivalent about the SCS design. I think that the SCS got delayed repeatedly throughout the 1970s. Eventually the Navy decided that it required a faster replacement for the S-2 and it could operate off of big deck carriers, so it could be heavier. That's how they ended up with the S-3 Viking.

The SCS design was later adopted by a foreign navy. I'd have to look it up, but Spain or Italy has essentially built one of those ships. I'm not sure if they used an American design team, but the exterior of the ships are very similar.
Clioman said:
Thought I'd post it in case there's still interest.

Yes indeed!!!!!!

Thanks for your time and effort!

The NAA design looks very clean.


I'd have to dig through my stuff to find them. However, around 1971 or so they proposed a tilt-wing aircraft for sub-hunting. Then they later proposed the aircraft above, which lost to the S-3.

Yes please do!
Look forward to it!!

Hi All!

Apologize for the quality of.

"Artist's concept shows one of the versions of the VSX carrier-based anti-submarine warfare aircraft under study at McDonnell Company."

Source: Technology Week, 1967, Vol.20, 27 March, page.47


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In my excitement of sorting through my boxes of books, I feel that I have hit a jackpot of sorts.
For I found an envelope which was sent to me via the Vought Retire Club a few years back which I had not even opened.

In it I found snippets of information pertaining to LTV's involvement in the USN's VSX program.

With the info I have, Lockheed - California Co. (CALAC), submission was designated CL995-20 or 'CALAC-19' by LTV.
Somewhere in this equation CALAC must have approached LTV because of their lack of carrier design and operability history.
LTV came on board and was very taken back by what they sore in the CL995-20. On the hand written notes I have LTV's engineers describe the CL995-20 as a giant.

I have copies of a presentation, which was given to Lockheed management by LTV's Roger Ringham, Vice president of Engineering, which lists the following -

Sheet 1
LTV Critique of CALAC-19 Configuration
- Excessive Size of Airplane
- Unsuitable Main Landing Gear
- Inadequate Structural Continuity
- Fuel and Armament in Wing Outer Panel
- Buffet
- Inefficient Internal Arrangement
- Large Roll to Yaw Ratio and Adverse Sideslip

Sheet 2
LTV's List of Changes to CALAC-20 Configuration
1. Increased Radome Length 10 inches
2. Increased Slope of Windshield to 50-degrees
3. Added Side Canopy Frames
4. Added A-7 Type Nose Gear
5. Added Avionics Compartments on Either Side of Forward Keels
6. Moved Bomb Bay Approx 22-inches Closer to Airplanes CG.
7. Added Aft Retracting Tripod Type Main Landing Gear
8. Swept Vertical Tail
9. Moved tail Hook Aft
10. Moved MAD Boom Up Into Upper Half of Fuselage
11. Located Cabin Entry Door in Lower Fuselage Between Main Fuselage Structural Keels
Behind Main Landing Gear
12. Folded Length of Airplane Measured to Trailing Edge of Vertical Tail Folding Hinge Line

Sheet 3
- The VS(X) requirements Can Be Met By An Airplane With A Length of 48 Feet and Gross
Weight of 40,000 Pounds

I can not but help think that LTV engineers and know how had far more input and doing into making the Lockheed S-3A Viking what we know of today, with sadly very little credit being given to it.
It begs me to question if LTV turned this Lockheed design around so much why is it not designated Lockheed-LTV S-3 Viking!



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Very interesting find indeed! Now THAT could explain in part why the Viking never quite looked Lockheed to me...
Thanks Pioneer - that goes a long ways towards explaining some of the stuff I copied on this trip to Vought. I'll get that scanned and posted shortly.

Enjoy the Day! Mark
FWIW, it was reputed that the North American Rockwell design was a better airframe than the Lockheed bid. But the S-3 was an avionics truck...and the contents were more critical than the airframe.

BTW, there seems to be some confusion here. The USN had the VSX program, for an S-2 replacement. There were other design studies for an equivalent V/STOL capability for the Sea Control Ship. They never panned would up with a grossly overpowered aircraft.
It also helps explain why, IIRC, the S-3 used the landing gear from the A-7.

Stargazer2006 said:
Very interesting find indeed! Now THAT could explain in part why the Viking never quite looked Lockheed to me...
Greetings All -

Here's a few drawings of the Vought VS(X) Design. Not a bad looking design and if true, then you can see how it was rolled into the S-3 design.

Enjoy the Day! Mark


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Decent accounts of the S-3 program have always noted that LTV was a major subcontractor (24% share) brought in for their naval experience. GD teamed with Grumman for the same reasons.
overscan said:
Decent accounts of the S-3 program have always noted that LTV was a major subcontractor (24% share) brought in for their naval experience. GD teamed with Grumman for the same reasons.

Most certainly, yes. But there is a difference being a subcontractor on a program, even a major one, and having designed the final version of it! Here, obviously, the final Viking is 95% similar to the Vought proposal, and has little to do with Lockheed's. Vought was the main contractor on the Northrop B-2 frame, but I don't think they participated in its design. Grumman DID participate in the design of the F-111B but were credited for that. The way Lockheed appropriated the Vought design as their own while Vought is only credited with subcontracting, however, doesn't seem so common to me.
Actually, as a major subcontractor, Vought was a major participant in the design of the B-2. I worked closely with a number of their people and visited their Texas facility several times while working on the B-2 for Northrop.
Greetings All -

Here is the McDonnell Douglas (Douglas side of the company) submittal for the VSX program - the Model MD-893. The drawing and artwork are pulled from the Stability and Control Volume of the proposal. Interesting in looking at the graphs was a deep stall issue with the layout - a big negative against the proposal. The design appears to have some elements of the Piaggio Douglas PD-808 which Douglas looked at producing.

I have scanned the summary and some additional drawings and charts to PDF. Will talk with Overscan to post it in thread as it is over the file size limit.


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[American Secret Projects - Bombers, Attack and Anti-submarine Aircraft 1945-1974 by Tony Buttler -added by Admin for clarity]

Does it have much on the two rounds of competition for US Navy ASW planes in the late 1960s/early 1970s? If I understand it correctly, the first round was for a VTOL ASW plane to serve on the proposed Sea Control Ships. There was at least one proposal from Convair (mentioned elsewhere here), but I think there were a few others. That competition never went anywhere, and then there was the second round that resulted in the S-3 Viking.
Tony's book only has a paragraph on VSX. I've slung this together for you - it makes the timelines much clearer.

VSX was first circulated in mid-1964, and Lockheed, Douglas and McDonnell were awarded contracts for concept formulation, and submitted their designs in during 1966. This was followed by the release of the Specific Operational Requirement in Winter 1966. Bids were submitted to the official RFP in April 1968, then in August 1968 two teams were asked to refine their designs - Convair / Grumman /IBM and Lockheed / LTV / Univac. The final submissions were made in December 1968 and Lockheed announced as winner on 4 August 1969.

Specific VSX designs known are
General Dynamics Convair Model 21
Grumman G-304
McDonnell-Douglas (McDonnell) Model 201
McDonnell-Douglas (Douglas) MD-893
Lockheed CL-806 (early concept), CL-995 (later concept leading to S-3 Viking).
North American Rockwell VSX (model number unknown)
Vought VSX (model number unknown)
Martin (according to Tony Buttler - seems unlikely as they were out of the aircraft business by then?)

Convair teamed with Grumman for their naval aircraft experience, just as Lockheed teamed with LTV.
I came across these photos of the mockup of the Convair (San Diego) VSX proposal at the San Diego Air & Space Museum Archive (SDASM) on Flickr. It is described as the "Convair S-3A" in the caption (the stillborn aircraft's designation if the Convair proposal were chosen). Presumably, this is the Convair Model 21. Here are two of the photos, plus a couple of mystery photos that somehow were in the "Convair: S-3A" sequence of photos and captioned as such.
Convair: S-3A

Convair: S-3A

Here's the intriguing head-scratcher in the "Convair: S-3A" sequence of photos at he SDASM Flickr photostream. It's captioned as "Convair: S-3A" but apparently characterized incorrectly. It hardly seems to be related to the Convair Model 21 or the VSX proposal.

It's a mock-up of some sort, but given the full pressure suit and helmet, it's a mock-up for something far higher and swifter than any ASW aircraft.
"Convair: S-3A" Mystery Photo No. 1

"Convair: S-3A" Mystery Photo No. 2
Well the way the pressure-suited chap's seat is located so as to be able to manouver his upper torso into the cut-out in the display make me wonder if it's some kind of recce craft - with some sort of scope being located in the cut-out.
Sure i saw something similar to this on a discovery channel doc, about manned space based recon satellites, probably wrong, and can't recall what the project was called, sure there's a thread here somewhere!
overscan said:
Mark's scan of the report is uploaded here, enjoy.

Thanks Mark, and thanks Overscan
An interesting insight into McDonnell Douglas' design study!

Greetings All -

I had the chance to spend the day looking thru and scanning stuff from Gerald Balzer's collection and found these images of the McDonnell Model 201 VSX proposal. Check out the segmented flaps...

Enjoy the Day! Mark


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My pleasure - was surprised to see them. I think the model in the B&W photo is the Model 893 from the Douglas team.

Enjoy the Day! Mark
It says the photograph was taken in 1940, with supporting information about the photographer, etc.

I believe everything on the Internets to be true and accurate, so this pre-WWII turbofan-powered airplane represents a quantum leap in technology.
The collection of stuff appears to be mostly Curtiss-Wright with a smattering of North American Rockwell stuff. Connection would be Columbus, Ohio. Curtiss assets went to NAA in 1948 or so, so likely the engineer worked at NAA some time after 1948.

That might make this perhaps an alternative Rockwell design to this VFX concept?


Stanley I. Vaughn, Sr. died Wednesday, March 9, 1972 at his home in Columbus, Ohio. He was 85.

He first flew a glider down a hill near Cleveland in April 1907. After that he worked on dirigibles and made his first flight in one near Toledo in 1909, ending in near disaster in the Maumee River.
A few years later Vaughn built and flew his own airplane. He soon went into the business of building them for the Curtiss Airplane Company. During World War II, he went to Columbus as manager for the Curtiss Wright Co. and stayed on when North American Aviation took over the plant. He retired in 1957.
He is survived by his wife, a son, Stanley Vaughn, Jr. and two grand children.
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