EC-121 Proliferation?

[Rule of cool]

The USN acquired 142 Lockheed EC121s in the early 50s to mount long-range early warning barrier patrols in the Atlantic and Pacific. The main strength was 5 sqns for each ocean with various cats and dogs supporting units. The barrier patrol lasted until 1965 and afterwards the USN transferred 30 EC121 to the USAF, kept a lot of the cats and dogs units but as best as I can tell retired dozens of EC121 AEWs. In contrast the USAFs EC121 AEW fleet, and some of the remaining USN EC121 AEW aircraft, were upgraded, sent to war in Vietnam and worked hard for the next 7 or so years.


What if, instead of retiring them the US decided to push these AEW aircraft out to allies at cut rates from 1965? Which air forces would be candidates to operate them, in what numbers and what roles?


On the technical side early EC121s had the ventral APS20 search radar and the dorsal APS45 height finder, both with a range of about 70 miles for fighter sized targets. From 1962 USAF EC121s had upgraded APS95s replacing the APS20 but still had the APS45 on the back until the 2nd half of the 60s, but the USN didn’t upgrade the aircraft they retired. These aircraft are optimised for use over water, they aren’t much chop over land.

 

[Yellow Palace]

Which air forces would be candidates to operate them, in what numbers and what roles?

The RAF was interested in getting a dozen as part of the same 'shopping trip' as the F-111, F-4 and C-130. This would have been in place of the AEW Shackleton.

 

[Scott Kenny]

Definitely RAF, for the GIUK Gap.

Oz, maybe.

I can't really think of anyone else. Taiwan?

 

[Rule of cool]

I could see them being useful in the Adriatic and Baltic Seas, but maybe that's a NATO sqn like the E3s. Japan could make use of them, but Sth Korea is probably too immature at the time. The same applies for Iran and Turkey who have strategic coastlines. Canada might be another candidate.

At low level the APS95 radar signal could bounce off the sea and provide medium level coverage as far inland as Hanoi. That would be handy on the Soviet and other peripheral areas, but I think the APS20 radar was too short-range for this to be useful.

 

[TsrJoe]

72 scale model by Martin Higgs, IPMS. Project Cancelled SIG. display, SMW. Telford 2021

 

[Rule of cool]

Cool!

Waa the RAF going to get standard ex USN EC-121s or was the plan to get APS-95 search and APS- 103 height finder radars?

 

[Yellow Palace]

Cool!

Waa the RAF going to get standard ex USN EC-121s or was the plan to get APS-95 search and APS- 103 height finder radars?

Unclear - @CJGibson mentions it in a couple of his books, but there's not really much beyond up to twelve EC-121s for AEW in the East of Suez role. Possibly ex-USAF, but at that time second-hand would more likely mean ex-USN. He might know more... it may even be in his new book!

 

[Scott Kenny]

Cool!

Waa the RAF going to get standard ex USN EC-121s or was the plan to get APS-95 search and APS- 103 height finder radars?

Getting USN airframes wouldn't prevent a radar refit.

 

[Rule of cool]

No, but that would cost money

 

[CJGibson]

Unclear - @CJGibson mentions it in a couple of his books, but there's not really much beyond up to twelve EC-121s for AEW in the East of Suez role. Possibly ex-USAF, but at that time second-hand would more likely mean ex-USN. He might know more... it may even be in his new book!

I don't recall any mention of a specific variant and they were for the short-lived Mounting Bases in the Indian Ocean. I could have a look in my files when I get home, but those levels of discussion rarely got into specifics.
I can only comment that it would have been whatever variant was cheapest!

Chris

 

[Yellow Palace]

I can only comment that it would have been whatever variant was cheapest!

The lack of a purchase does suggest that 'don't bother' turned out to be cheaper still.

 

[Grey Havoc]

The Imperial Iranian Air Force might well have been another potential user. Not least because of Iran's involvement in Project Dark Gene and Project Ibex.

 

[Grey Havoc]

The lack of a purchase does suggest that 'don't bother' turned out to be cheaper still.

I seem to recall hearing that HM Treasury had a tendency back then of going for jets, preferably American made, even in cases where the designs involved were actually inferior (not to mention more expensive) to British designed and/or made kit. There may have been elements within both the Treasury and the Foreign Office thinking (rather foolishly) that Britain would be able to buy into the USAF's newly established AWACS program on the cheap.

 

[GTX]

RAAF conceivably

 

[Rule of cool]

The Imperial Iranian Air Force might well have been another potential user. Not least because of Iran's involvement in Project Dark Gene and Project Ibex.

I was thinking Iran too, for the Caspian Sea as well as the Gulf and Arabian Sea. However in 1965 the IIRAF was very primitive indeed, they had Sabres that they gave to Pakistan and got their first 11 F5As in early 1965, with 104 plus 25 F5Bs delivered by 1972. Their first 16 of 32 F4Ds arrived in late 1968, RF4Es in 1970 and F4Es in 1971. I doubt such a fledgling force could have operated something as advanced and likely temperamental as an EC121 in 1965-66 and even if they could they lacked the fighter force to do anything with the radar info they gained.

 

[Rule of cool]

With the RAF, they trialed APS20 equipped Neptunes in 1953-56 but apparently weren't overly impressed. I'm not too surprised, the APS20 had a fighter detection range of about 75 miles and could only look down, so only gave a low level coverage 150 miles across, which isn't much really and at the time high level was the preferred penetration method.

The RAF didn't convert the 12 Shakeltons to AEW models until the RN's 849 NAS began to run down from 1968 making APS20 radars and the kit from Gannet AEW available for free. It's heartening to know that the RAF wouldn't look a gift horse in the mouth and would pick up AEW if it was available, at least they recognized that level level penetration needed to be countered.

 

[Apophenia]

... Canada might be another candidate...

That makes an odd sort of sense ... assuming that those radars performed decently over ice. A surplus EC-121D purchase would have a degree of engine commonality with RCAF Argus and Neptunes. In a pinch, airframe heavy maintenance could have been outsourced to TCA Montreal (although that's often tricky with classified military systems on board).

But, since we're in AltHist here, maybe Canada only takes the electronics? The APS-95, APS-103, and associated operators' stations are then transferred to available Argus Mk.Is or even Yukon airframes. [1] Out this deal, the US gets added coverage north of 60° and Ottawa gets to spread more work around Montréal ... sucking up to Québécois/Québécoise voters for the Nov 1965 general election
______________________________________________

[1] Here, I'm imagining Transport Command surrendering a few CL-44-6s in exchange for CL-44D 'swing-tail' replacements.

 

[Scott Kenny]

That makes an odd sort of sense ... assuming that those radars performed decently over ice. A surplus EC-121D purchase would have a degree of engine commonality with RCAF Argus and Neptunes. In a pinch, airframe heavy maintenance could have been outsourced to TCA Montreal (although that's often tricky with classified military systems on board).

But, since we're in AltHist here, maybe Canada only takes the electronics? The APS-95, APS-103, and associated operators' stations are then transferred to available Argus Mk.Is or even Yukon airframes. [1] Out this deal, the US gets added coverage north of 60° and Ottawa gets to spread more work around Montréal ... sucking up to Québécois/Québécoise voters for the Nov 1965 general election
______________________________________________

[1] Here, I'm imagining Transport Command surrendering a few CL-44-6s in exchange for CL-44D 'swing-tail' replacements.

I think Canada would prefer to take a whole working aircraft over trying to bodge something together in the shed.

It's the UK that would bodge stuff together in the shed.

 

[Rule of cool]

Canada is probably the most tenuous user. Its home defensive warning needs don't really need an AEW that's useful only for low level detection over water. Similarly its NATO commitment doesn't really need that capability either. That leaves a sort of residential requirement to maybe do something over the NW Atlantic. So while Australia might make use of 6 EC121 Canada might only use 4.

 

[Pioneer]

RAAF conceivably

Indeed GTX, hopefully the RAAF having the fortitude to have them fitted with P&W T34 turboprop engines - an AEW derivative of the C-121F.


Regards
Pioneer

 

[TsrJoe]

India would be an obvious one, picking up on the envisaged role intended for the RAF. Warning Star's ...

Indian Air Force and Navy Super Constellations

 

[BlackBat242]

A couple of missed opportunities:


EC-121L (WV-2E): One modified WV-2, testbed for rotating radar dome with an AN/APS-70 radar, first flight 1956.

Lockheed WV-2E Warning Star (BuNo 126512, c/n 1049A-4301) modified with the radar in a rotodome above the aircraft. This aircraft was retired to NAF Litchfield Park, Arizona (USA), for storage on 5 June 1962. It was redesignated EC-121L in November 1962 and scrapped on 18 February 1965.









Four R7V-1s (military L-1049s) were converted to R7V-2s by removing their 4 x 3,250 hp R3350 engines and installing 4 x 5,531 shp T34 turboprop engines (also used on the Douglas C-133 Cargomaster). This increased max speed from 330 mph to 479 mph, and similarly increased rate-of-climb.

Two were built in 1954 for the USN and two in 1955 for the USAF (designated C-121F).








Put turboprops on the WV-2E, and you've got an early AWACS.

An alternate engine instead of the T34 would be the T56.
One of the USAF C-121Fs was used by Lockheed as a testbed for the Allison 501D turboprop (civil version of the T56 in the YC-130 and intended for the L-188 Electra - from which the P-3 Orion was developed).

The T56 started at 3,750 shp in the C-130A (with 3-blade props) in 1956, but quickly improved to 4,050 shp in the C-130B in 1959 (with 4-blade props) and 4,910 shp by 1962 (P-3C)... although not as powerful as the T34, this would still be a definite improvement over the R3350 engine, and had better fuel efficiency than the T34 - .54 lb fuel/horsepower/hour for the T56 vs .65 lbf/hp/hr, a 20% improvement.

 

[Rule of cool]

Indeed GTX, hopefully the RAAF having the fortitude to have them fitted with P&W T34 turboprop engines - an AEW derivative of the C-121F.


Regards
Pioneer

I doubt any user picking up these aircraft will spend money on re-engining on such old and obsolete airframes, although radar and electronic updates are another matter as the USAF paved the way with the APS-95 update. I think the EC121s would last until about 1980 in the new user's service which would make the airframes over 25 years old.

What it would do is stimulate the requirement for a 'medium' AEW aircraft. By the mid 70s the radar from the E2 was capable enough that it could be mounted in something like a P3 or even a B737 and given 6 or so consoles compared to the E2s 2 and E3s ~10.

 

[BlackBat242]

I doubt any user picking up these aircraft will spend money on re-engining on such old and obsolete airframes, although radar and electronic updates are another matter as the USAF paved the way with the APS-95 update. I think the EC121s would last until about 1980 in the new user's service which would make the airframes over 25 years old.

What it would do is stimulate the requirement for a 'medium' AEW aircraft. By the mid 70s the radar from the E2 was capable enough that it could be mounted in something like a P3 or even a B737 and given 6 or so consoles compared to the E2s 2 and E3s ~10.

You mean.....







US Customs anti-smuggling conversions of P-3Bs in the early 1990s with E-2C radar suites.

Or this:



One C-130H converted to EC-130V with E-2C radar suite - now in use by the USAF for radar development.

Lockheed is offering a conversion of C-130J-30 airframes with the E-2 radar suite, "9 or more" operator consoles can be fitted.

 

[Kiltonge]

From Flight, 07 Apr 1966. Hilarity as the RAF rejects the idea of an AWACS based on old, piston-engined airframes

Unfortunately the 17 Feb 1966 page referenced in the RN E-2A comment wasn't scanned.

 

[BlackBat242]

From Flight, 07 Apr 1966. Hilarity as the RAF rejects the idea of an AWACS based on old, piston-engined airframes

Unfortunately the 17 Feb 1966 page referenced in the RN E-2A comment wasn't scanned.

Indeed... when did they convert the Shacklebombers into Shaklebulges?

Ah, yes... 5 years after the above article.

 

[Rule of cool]

I recall the P3 aew being proposed and flown when I was at school in the 80s, but it didn't take off and get a bunch of orders. However if the EC121 was pushed out to allies these proposals would become reality in the 70s and 80s.

 

[Rule of cool]

From Flight, 07 Apr 1966. Hilarity as the RAF rejects the idea of an AWACS based on old, piston-engined airframes

Unfortunately the 17 Feb 1966 page referenced in the RN E-2A comment wasn't scanned.

Its a bit rich to reject the EC121 for its piston engines when the altitude that puts the 150 mile fighter direction range of the APS-95 on the horizon is 15,000'. You need a powerful radar indeed to make flying higher than that worthwhile.

 

[Kiltonge]

For the pittance they would have cost, and they ability to train and tour with the USAF, it's incredible that they declined the offer. And surely it would have provided more leverage over the Navy, having the ability to patrol hundreds of miles out of just about any base.

As it transpired, when 8 Sqn stood up with the Shack AEW they had to borrow 26 Gannet operators from the Navy as they had no AWACS cadre. And of course it lacked any height-finding capability which made directing Lightnings tricky.

 

[Pioneer]

I doubt any user picking up these aircraft will spend money on re-engining on such old and obsolete airframes, although radar and electronic updates are another matter as the USAF paved the way with the APS-95 update. I think the EC121s would last until about 1980 in the new user's service which would make the airframes over 25 years old.

What it would do is stimulate the requirement for a 'medium' AEW aircraft. By the mid 70s the radar from the E2 was capable enough that it could be mounted in something like a P3 or even a B737 and given 6 or so consoles compared to the E2s 2 and E3s ~10.

I'm thinking, if the price is right, the performance and operational gains with the T34 obvious, then why not. After all Australia has (F-111) and continues (F/A-18E/F and E-7 Wedgetail) to go out on a limb from time to time.

Regards
Pioneer

 

[Rule of cool]

For the pittance they would have cost, and they ability to train and tour with the USAF, it's incredible that they declined the offer. And surely it would have provided more leverage over the Navy, having the ability to patrol hundreds of miles out of just about any base.

As it transpired, when 8 Sqn stood up with the Shack AEW they had to borrow 26 Gannet operators from the Navy as they had no AWACS cadre. And of course it lacked any height-finding capability which made directing Lightnings tricky.

It's interesting that the EC121 were being considered for EoS in support of the RAFs 'Island Bases' strategy that 'defeated' the RNs carrier strategy to handle the EoS task. I'm not a fan of the Island Bases strategy and think the EC 121 would be useful over the North Sea in the Flexible Response strategy NATO formally adopted from 1967 if Britain plays its other card right..

 

[Rule of cool]

I'm thinking, if the price is right, the performance and operational gains with the T34 obvious, then why not. After all Australia has (F-111) and continues (F/A-18E/F and E-7 Wedgetail) to go out on a limb from time to time.

Regards
Pioneer

By the time we ordered the Wedgetail in 1999 AEW/AWACS was well and truly proven as 'must have' capability, but this wasn't the case in 1965-66 when these EC121s became available. The RAF's experience is instructive; they trialed AEW in 1953-56 but didn't adopt it, were offered EC121 in ~1966 but rejected it and then threw together the minimum capability AEW for as cheap as humanly possible in 1972. The US experience with the EC121 as well as E1 and E2 in Vietnam proved the AEW/AWACS had a lot of potential for things other than anti-bomber and anti-ship detection over the oceans.

In the 'try the new thing and see' environment that the RAAF would get the EC121 it would be a big gamble indeed to invest so much time and money in new engines for something that may not pan out, or be too costly or niche for the RAAF.

 

[Rule of cool]

Here's a table of these early AEW radars, their detection range against fighter-size targets and the cruising altitude needed to put that range onto the horizon to detect such targets at low level.

Radar	Aircraft	range	altitude
APS-20E-F	EC121, Neptune, Gannet, Skyraider, Shackelton	90-115 miles	3-5,000'
APS-70 (only 3 built for testing)	EC121 (1 trail aircraft)	250 miles	40,000'
APS-82	E1 Tracer	110 miles	8,000'
APS-95	EC121	150 miles	15,000'
APS-96	E2A	200 miles	35,000'
APY-1	E3A	250+ miles	40,000'

As can be seen the APS-20 installed in the Shackelton as late as 1971-72 offers pretty feeble capability, a detection circle ~150 miles across. This is a handy capability for the RN in the 60s with the Gannet operating in concert with the ship's radars including the awesome Type 84, but not much chop for the RAF operating independently over the North Sea and GIUK Gap.

It really takes the APS-95 upgrade with its ~300 surveillance circle in the EC121 to make independent AEW&C practical. In Vietnam USAF EC 121s could get a medium level radar picture over Hanoi and the nearby MiG base when operating over the sea some 100+ miles away.

 

[Apophenia]

I think Canada would prefer to take a whole working aircraft over trying to bodge something together in the shed...

I'll see your EC-121 stake and raise you one CP-140 programme

 

[isayyo2]

Put turboprops on the WV-2E, and you've got an early AWACS.

An operational WV-2E would need turboprops too!
The massive 30 ft rotodome holding the APS-70 had a severe impact on performance...

SAGE: Semi-Automatic Ground Environment Air Defense System | MIT Lincoln Laboratory

The Semi-Automatic Ground Environment, or SAGE, was the nation's first air defense system and was the impetus for the establishment of Lincoln Laboratory. The sections below describe the history of this seminal, large-scale system-engineering project, and the role that it had in shaping the...

www.ll.mit.edu

"To improve target-detection performance and at the same time to narrow the beamwidth of the UHF radar, the Navy's Bureau of Aeronautics sponsored the installation of a large rotating radome high above the fuselage of a Super Constellation. One of Lincoln Laboratory's AN/APS-70 AEW radars was installed in the fuselage. Although the combination proved to be very effective, tests of the aircraft showed it was often on the verge of stalling."

Now the "ultimate" EC-121 variant seems to be the "CL-257 (USN W2V-1) late-1956 factory model, based on the L-1649 Starliner, but with turboprops and wingtip jets. This last Constellation also lost its signature triple fin (although the XW2V-1 still had it.)" as discussed in this thread.

 

[Rule of cool]

The APS-70 was pretty early, 1956 I think.

It's interesting that the APS-70 was tested, and the turboprops needed to power the aircraft were also tested yet the far less powerful APS-95 was actually fielded. It's probably an example of sunk costs, the APS-95 could be fitted to already in service aircraft whereas the APS-70 would have required all new aircraft.

That said, if a turboprop APS-70 was actually fielded in operational numbers I doubt it would be divested in 1965 like the actual APS-20 (95?) equipped fleet was.

 

[Scott Kenny]

I doubt any user picking up these aircraft will spend money on re-engining on such old and obsolete airframes, although radar and electronic updates are another matter as the USAF paved the way with the APS-95 update. I think the EC121s would last until about 1980 in the new user's service which would make the airframes over 25 years old.

What it would do is stimulate the requirement for a 'medium' AEW aircraft. By the mid 70s the radar from the E2 was capable enough that it could be mounted in something like a P3 or even a B737 and given 6 or so consoles compared to the E2s 2 and E3s ~10.

There's a good argument for swapping to turboprops due to much better fuel economy and therefore range/loiter time.

It's interesting that the EC121 were being considered for EoS in support of the RAFs 'Island Bases' strategy that 'defeated' the RNs carrier strategy to handle the EoS task. I'm not a fan of the Island Bases strategy and think the EC 121 would be useful over the North Sea in the Flexible Response strategy NATO formally adopted from 1967 if Britain plays its other card right..

Agreed, that would have been a good plan.

I'll see your EC-121 stake and raise you one CP-140 programme

Touche.

 

[Rule of cool]

I think I'm going to have to re-asess my estimates of the capability of the APS-20 radar. Early versions had a detection range of ~75 miles for fighter sized targets, but the F model increased this to ~90 miles and the bigger E model ~115 miles. Presumably the EC121 used the bigger E variant, so could cover a circle 230 miles across instead of 150 miles.

The Gannet used the later E variant, although I don't know if this small aircraft had the 'bigger' version or an updated but small version.

 

[Pioneer]

I doubt any user picking up these aircraft will spend money on re-engining on such old and obsolete airframes, although radar and electronic updates are another matter as the USAF paved the way with the APS-95 update. I think the EC121s would last until about 1980 in the new user's service which would make the airframes over 25 years old.

What it would do is stimulate the requirement for a 'medium' AEW aircraft. By the mid 70s the radar from the E2 was capable enough that it could be mounted in something like a P3 or even a B737 and given 6 or so consoles compared to the E2s 2 and E3s ~10.

Hence the Lockheed CL-140-15 ALRI study in the late 1950, which predated the P-3 AEW.

Unfortunately, I wrote to Lockheed Martin in the hope they could give us more details of the CL-140-15 ALRI, sadly to no avail....

Regards
Pioneer

 

[Rule of cool]

In the late 50s I'd think AEW was seen as a niche capability, useful mostly for over water which is why the RAF rejected it in 1956 but the RN embraced it and the USN acquired 142 EC121 and 88 E1 Tracer but the USAF only acquired 84 EC121.

It wasn't until the development of pulse doppler radars and advanced signal processing allowing overland operations that demand for AEW became widespread.