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Author Topic: Lockheed S-3 Viking Variants and Projects  (Read 36376 times)

Offline blackstar

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Re: Lockheed S-3 Viking Variants and Projects
« Reply #15 on: September 28, 2012, 02:14:45 pm »
Thank you for that. Here is an excerpt:

"One of the interesting derivatives of the "stock" S-3A was a modification for the "carrier on-board delivery (COD)" cargo / personnel transport role. Lockheed initially proposed a major redesign of the Viking for COD operations, featuring a longer and wider fuselage with a rear loading ramp and accommodations for 30 passengers, plus more powerful engines to handle the bigger airframe.  The Navy didn't buy the idea, so Lockheed came up with a minimum-change solution, originally given the designation "S-3A(COD)" but then redesignated "US-3A".  Combat avionics were removed, with a color navigation radar and a LORAN-Omega navigation beacon receiver installed.  The seats for the SENSO and TACCO were removed, though a place was installed for a loadmaster.  The US-3A could carry six passengers or up to 2,125 kilograms (4,680 pounds) of cargo internally in a cargo hold with 7.6 cubic meters (10 cubic yards) of usable space.  It could be fitted with either an external tank or a cargo pod under each wing, depending on whether the mission demanded range or load.

  One of the original YS-3A Viking prototypes was converted as a demonstrator, performing its first flight on 2 July 1976.  The Navy was impressed, but decided to standardize on the Grumman C-2A Greyhound instead.  However, the Navy did acquire six more US-3A conversions to meet a specialized COD requirement.  They provided service during the Gulf War, but were retired in the mid-1990s.  One was lost in a crash.  The US-3A's cargo pods, known as "blivets", were carried on other Viking variants on rare occasions."


I think that there are actually three COD versions that were proposed or built:
1-the original COD proposal, with a much larger fuselage.
2-the actual US-3A COD that was built, essentially consisting of the standard fuselage with the interior stripped out to serve in the COD role.
3-the COD version mentioned in Polmar's Naval History magazine article, which would have consisted of the basic S-3 airframe with a 70-inch fuselage plug. The article linked above does not refer to that version.

Online hesham

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Re: Lockheed S-3 Viking Variants and Projects
« Reply #16 on: November 01, 2012, 08:47:00 am »
Also AIBF,ultra-STOL concept,fitted with four engines;

To assess the AIBF ultra-STOL performance  potential,the experimental data
developed by the NASA/USAF/Lockheed large-scale tests for the AIBF concept
were used for analyzing the deck performance of a typical sea-based aircraft
configuration.Figure 10 depicts this conceptual AIBF ultra-STOL configuration
which had an aspect-ratio  7.73 wing of 68-ft span and a wing area of
598 sq.ft.The power plants were four TF34-GE-2 turbofans. It was assumed
that the TF34/AIBF installation was similar to the AIBF  application scheme
shown in Figure 1b and that the flap setting for both takeoff and landing
configurations was 30 degrees.

http://www.dtic.mil/dtic/tr/fulltext/u2/a078909.pdf


« Last Edit: November 06, 2012, 01:55:04 pm by hesham »

Online hesham

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Re: Lockheed S-3 Viking Variants and Projects
« Reply #17 on: November 06, 2012, 01:58:56 pm »
Hi,

amazing V/STOL concept to the Lockheed S-3 Viking,with changing the
land gear system.


http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19800015801_1980015801.pdf


Offline PaulMM (Overscan)

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« Last Edit: January 04, 2013, 09:38:17 pm by PaulMM (Overscan) »
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Offline PaulMM (Overscan)

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Offline Bill S

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Re: Lockheed S-3 Viking Variants and Projects
« Reply #20 on: September 28, 2013, 07:20:20 am »
Two images of the Viking AEW concept.


The first is a PK Nagata artists concept of the Viking AEW getting ready to launch
The second is a different scan of the same poor image of a Viking AEW model
Both from Vought Aircraft Historical Foundation archives.


bill

Offline Bill S

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Re: Lockheed S-3 Viking Variants and Projects
« Reply #21 on: September 28, 2013, 08:14:07 am »
I also found this graphic for the program.
VAHF


bill

Offline blackstar

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Re: Lockheed S-3 Viking Variants and Projects
« Reply #22 on: November 23, 2013, 07:36:17 pm »
Proposed revised version of Viking COD. New fuselage.

Offline Triton

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Re: Lockheed S-3 Viking Variants and Projects
« Reply #23 on: November 23, 2013, 08:17:39 pm »
Proposed revised version of Viking COD. New fuselage.

Related topic:

"Common Support Aircraft  (C-XX) competition [2014]" 
http://www.secretprojects.co.uk/forum/index.php/topic,19148.0.html
« Last Edit: November 23, 2013, 08:23:50 pm by Triton »

Offline Jemiba

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Re: Lockheed S-3 Viking Variants and Projects
« Reply #24 on: November 24, 2013, 02:00:06 am »
Maybe the results of the X-55 ACCA could be incorporated ?

It takes a long time, before all mistakes are made ...

Offline blackstar

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Re: Lockheed S-3 Viking Variants and Projects
« Reply #25 on: November 24, 2013, 06:23:18 am »
I wish they had released a better illustration of the aircraft. I am curious as to how they add a larger fuselage to an existing cockpit. Is it just longer or do they increase the width?

Offline Jemiba

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Re: Lockheed S-3 Viking Variants and Projects
« Reply #26 on: November 24, 2013, 08:54:59 am »
My interpretation is an increased length, a higher set wing and maybe
taper of the rear fuselage on a shorter length of the aft fuselage, so
retaining the maximum width on a longer part of the cabin.
It takes a long time, before all mistakes are made ...

Offline aim9xray

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Re: Lockheed S-3 Viking Variants and Projects
« Reply #27 on: November 24, 2013, 09:44:56 am »
Going by the article, both widened and lengthened .  They will have some interesting challenges due to "knock-on" effects.

- If they are to keep the wing intact, they are limited as to how much the fuselage can be widened - this is driven by the current engine placement (i.e. you can't move the engines outboard to make room for more fuselage width).  As a very rough guess, they can't bump out the fuselage sides more than 9-12 inches on either side. (The reduced clearance could have some aero effects as well as impede maintenance accessibility to the inboard side of the engines.)

- The fuselage outer mold line would probably be bumped out on the sides like that of the 747 Dreamlifter.

- Raising the wing above the "cargo box" of the fuselage means that the empennage group must be raised by roughly the same amount; this driven by the need to have the engine exhaust plume not interact (much) with the horizontal stabilizer.

- Tying in the new fuselage structure to the existing cockpit/nose landing gear structure will be a challenge; the S-3 was designed around a very efficient dual keel beam structure that reacted longitudinal loads all the way from the nose landing gear (cat loads) to the main landing gear, to the tailhook (trap loads).  The depth of this structure will have to be greatly diminished in the cargo box to make room for, well, cargo; the transition to the existing structure under the cockpit will be interesting.   On the other hand, they won't have to have the gaping [structural] holes in the current upper forward fuselage for the back seaters to eject through.

I would imagine that a lot of the initial groundwork for this was done by Lockheed and Vought in the late 70s/early 80s when last a new COD aircraft was needed.  (The customer's solution then was to reprocure the C-2 essentially "off the shelf" rather than engage in a development effort.) 

My thoughts anyhow, YMMV.

Offline blackstar

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Re: Lockheed S-3 Viking Variants and Projects
« Reply #28 on: November 24, 2013, 01:12:28 pm »
I think that the COD requirement is to be able to carry an F110 engine without any disassembly. So they need a fuselage that can hold that.

But I agree that eliminating the taper at the back could constitute "widening."


Offline aim9xray

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Re: Lockheed S-3 Viking Variants and Projects
« Reply #29 on: November 24, 2013, 03:13:08 pm »
If that is still a requirement, it's an anachronism - F110 powered the F-14D which is long gone.  Engines in use by the air wing are F414, F404, J52 (vanishing), T700 and T56 (am I missing any?).  I think the driver is probably the number of passengers.

C-2 allows six rows of 2+2 seating plus one row of 2, current S-3 width would give you rows of 1+1 with a slightly wider aisle and seats.