Grumman E-2X Hawkeye

By the 1990s the Grumman E-2 Hawkeye had already been about 30 years old. Also, at the time Grumman had spent considerable research resources into conformal antenna arrays such that the Navy requested that Grumman look into fitting a conformal array to the Hawkeye. Grumman began looking at ways to integrate the conformal array radar while maintaining most of the Hawkeye’s airframe commonality, landing gear and subsystems.

Grumman proposed the E-2X powered by the GE TF-34 turbofan (the same engine that powers the S-3 Viking and A-10). The conformal arrays would be fitted to the leading edges of the wing, fuselage sides, trailing edges and horizontal tail trailing edges. In order to house the array in the horizontal tail dihedral was removed and replaced by the same tail used in the C-2 Greyhound.

Removing the rotodome also had some effects to flying qualities when compared to the original E-2. longitudinal stability in the pitch axis necessitated a wing glove that also had additional fuel (which would make up for the fuel volume lost in the wings from antenna accommodation). The other major challenge in the E-2X was how to accommodate the TF-34 engines with changing the E-2C landing gear:

General Electric TF-34 Turbofan powers both the S-3 Viking and A-10 Warthog.
General Electric TF-34 Turbofan powers both the S-3 Viking and A-10 Warthog.

The solution was to “wrap” the TF-34 engine intake and exhaust ducts around the landing gear utilizing a split fan exhaust system…”

TF-34 cutaway drawing.
TF-34 cutaway drawing.

The resulting drag penalty would be overcome by using a slightly more powerful version of the TF-34.

Placement of the conformal array posed some unique problems. There were some problems with aircraft volume and weight distribution. The proposed number of transmitters posed weight and cooling problems resulting in additional complexity and therefore weight. Not to mention resulting changes to the flight control system based on the constraints of operating from an aircraft carrier.

Grumman's display model of the E-2X Hawkeye.
Grumman’s display model of the E-2X Hawkeye.

The E-2X was presented to the Navy and the E-2X program was shelved.

Source: The Aircraft Designers: A Grumman Historical Perspective.

A Not So Brief History of the Carrier Onboard Delivery, or COD

We mentioned a bit ago Brazil contracting to bring four C-1A Traders back into service, with an overhaul and update, to support their carrier both as a Carrier Onboard Delivery aircraft and as a tanker.

And yesterday, we brought news that the Navy has apparently decided the future COD for its carrier strike groups would be a variant of the V-22 Osprey.

Let’s spend a bit of time on the COD.

First up, speaking of the C-1A, there are a couple in the hands of private owners who fly them on the Warbird circuit here in the US.

'Miss Belle' at an air show in 2014. (photo via Doug Goss)

Memory fails me in my advancing years. I can’t recall if the Grumman I saw at the Goshen airshow in 98 was a C-1A (maybe this one!) or a US-2A, which was a standard S-2A Tracker that had all its ASW equipment stripped out, and was used as a utility plane.

As mentioned, the first dedicated COD for the US Navy was a modification of the World War II TBM Avenger torpedo bomber. Stripped of armament, it could haul the mail and a handful of passengers.

Long after the TBM was superceded as a combat aircraft, the TBM-3R served to transport priority passengers and cargo, serving well into the mid 1950s.

As previously noted, the UF-1, later redesignated the C-1A Trader, became the backbone of COD services through the late 1950s, the early 1960s, and soldiered on until the early 1980s.

http://cdn-www.airliners.net/aviation-photos/middle/0/3/8/1539830.jpg

The Trader was the last piston powered aircraft flown from US carriers.

The Trader was first supplemented, and later replaced in service by the C-2A Greyhound. Much as the Trader was an adaptation of the S-2 Tracker, the Greyhound took the wings, engine and empennage of the E-2 Hawkeye, and used a new fuselage to quickly produce a COD variant.

The first batch of C-2s were built in the early 1960s. After years of hard work, the C-2A was replaced by… well, more C-2s. The Navy contracted with Grumman to build a second batch of Greyhounds in 1984. The original batch has been retired, but the second production batch has been refurbished and updated with new propellers, much as the E-2 fleet, and continues in service.

But wait! There’s more!

While those are the primary aircraft used in the Carrier Onboard Delivery role, there are a few also-rans, a one-off, and some ideas that never came to fruition.

The Douglas A-1 Skyraider is legendary for its service in Korea and Vietnam as an attack aircraft. But Douglas also built a combat capable version that could (and did) double as a utility aircraft. The AD-5 (later A-1E) widened the fuselage a bit, and extended the vertical stabilizer, and replaced the single seat bubble canopy with a “greenhouse” that had a side by side cockpit for two, and seating for about 8-10 in the back.

Courtesy Detail and Scale.

The “Five” also served as the basis for quite a few night attack and electronic warfare variants of the Skyraider, including a predecessor to the E-1B Tracer and E-2 Hawkeye.  The Navy tended to use their –5 models as station hacks and utility aircraft, but the Air Force eventually used most of the vanilla A-1Es in Vietnam (or turned them over to the South Vietnamese Air Force) and used them to great effect as attack aircraft and in the Sandy role to support Combat Search and Rescue. Indeed, MAJ Bernie Fisher was flying an A-1E when he earned the Medal of Honor.

Much as the S-2 Tracker inspired a COD variant, the S-3 Viking did as well, but to  a much lesser extent. One S-3A was stripped of armament and sensors and had its cabin fitted for up to six passengers or two tons of cargo. Primarily used to support carrier operations in the Indian Ocean, its great range and (relative) speed made it useful for ferrying people and critical cargo from Diego Garcia to the carriers on Gonzo Station.

File:US-3A DN-SC-87-06468.JPEG

Recently Lockheed proposed pulling S-3s from mothballs and fitting them with a new fuselage to serve as CODs and tankers, but the extensive design and fabrication work required meant that idea was pretty much a non-starter when new build C-2s or V-22s were on the table.

Lockheed Wants To Bring The S-3 Viking Back From The Dead

While no COD variant of the venerable A-3 Skywarrior was built, it wasn’t uncommon for it to haul one or two VIPs when transiting from place to place. And for a time, the CNO used a VIP version as his personal transport, though I’m unaware of any CNO using it aboard a carrier.

Remember we mentioned the Navy had Grumman build a new batch of C-2s in the mid-80s? When word came out that the Navy was looking to replace its 1960s era Greyhounds, a couple of off the wall proposals for COD replacements were made.

Both McDonnell Douglas and Fokker proposed carrier capable variants of airliners for the job!

http://i57.photobucket.com/albums/g209/longranger/C-9COD2_zps176868c4.jpg

McD’s DC-9 proposal.

F28 COD 1

Fokker also realized a tanker would be popular.

F28

Neither proposal went much beyond some general sketches and marketing pics. It wasn’t so much that the Navy didn’t think a viable carrier variant could be made, but that operating such large aircraft from the tight confines of a carrier deck posed some real issues. If the plane broke down while aboard, it would really screw up the carrier’s ability to launch and recover other aircraft.

Speaking 0f big aircraft onboard, we can’t discuss COD w
ithout mentioning the largest trash-hauler to land aboard a carrier.

Yes, Jimmy Flatley III successfully landed and took off a C-130 Hercules from the USS Forrestal clear back in 1963. By the way, no tailhook, and no catapult!

[youtube https://www.youtube.com/watch?v=uM5AI3YSV3M]

But just because you could, doesn’t mean you should.

While we’re at it, a couple other oddballs pretending to be CODs, both of which have been featured here before.

The XC-124.

[youtube https://www.youtube.com/watch?v=buh7_xLG4ZE]

And the QSRA,

[youtube https://www.youtube.com/watch?v=k_eDutgh4IU]

We might not have chosen the V-22 to replace the C-2, but the fact is, someone has to provide priority cargo and personnel transport to the carrier group, and the V-22 is in production and in service. Better a bird in the hand than a power point program in the bush.

The Humble Trader keeps on CODdin’

Carrier Onboard Delivery, that is, the use of planes to provide logistical support to aircraft carriers, has been around pretty much as long as there have been carriers. The first dedicated COD aircraft was the TBM-3R, a modified Grumman Avenger with its armament removed, bomb bay sealed, and provisions for carrying passengers, mail, and cargo. But by the early 1950s, the Avenger CODs were getting old and tired, and their limited payload and range was also an issue. So Grumman devised a COD version of their highly successful S2F Tracker airplane. The wings, engine and empennage were the same, but the fuselage was somewhat deeper, looking for all the world like a pregnant Tracker. Originally designated TF-1, it was named the Trader, and first flew in 1955. Eighty-three were built, and would support the fleet until 1984. It was the last radial engine powered plane in the fleet.

File:Grumman C-1 flying side view.jpg

C-1A Trader

In the mid 1960s, Grumman would similarly adapt their E-2 Hawkeye wing, engine and empennage to a new, larger fuselage to produce the C-2 Greyhound COD, which first complemented, and later replaced the Trader in service. The Greyhound continues to support the COD mission to this day. 

File:C-2A DN-SC-89-09037.JPEG

C-2A Greyhound

Now a 60 year old design, out of service for over thirty years, you’d think the Trader’s story has come to a close. But wait, there’s more!

When France retired its aircraft carrier Foch in favor of the nuclear carrier Charles De Gaulle, Brazil bought Foch to replace its previous aircraft carrier, Minas Gerais*, and renamed her Sao Paulo. The Brazilians also bought Kuwait’s surplus A-4KU Skyhawks. Designated AF-1 in Brazilian service, these are excellent carrier aircraft, but they lack range.

Back in 2010, Brazil announced plans to purchase four C-1A Traders, and refurbish them for use as COD aircraft. The planes are in very rough shape.

Basically, the framework and sheetmetal are to be saved, and everything else, the engines, hydraulics, wiring, instruments and avionics will be brought up to 21st century standards. As an aside, re-engining S-2 Trackers with turboprop engines is a fairly standard modification, one that even CalFires has done with its S-2T tanker fleet.

The program has been somewhat stalled for the last four years, but finally, this week, Brazil signed a contract with Elbit Systems of America to perform the work. In addition to restoring them to flight and modernizing them, Elbit will add a refueling package to enable the Traders to refuel the Navy’s Skyhawks.

Elbit Systems of America, LLC, a subsidiary of Elbit Systems Ltd., announced today that it received a directed subcontract from the Brazilian Navy to upgrade four Grumman C-1A aircraft. The prime contract is held by Marsh Aviation Company of Mesa, Arizona. The subcontract, valued at $106 million, will be performed by Elbit Systems of America over a five-year period.

The upgrade work will be performed in San Antonio, Texas, at the facilities of M7 Aerospace, an Elbit Systems of America subsidiary, under the supervision of Brazilian Navy officers who are currently deployed to San Antonio. When upgraded, the Grumman C-1A aircraft will be designated as KC-2 COD/AAR (Carrier Onboard Delivery/Air-to-Air Refueling) aircraft, for the ultimate use on the Brazilian Navy’s aircraft carrier, the NAe São Paulo. AEL Sistemas S.A., Elbit Systems’ Brazilian subsidiary, located in Porto Alegre, Brazil, will provide in-country contractor logistic support services for the program as a subcontractor to Elbit Systems of America.

The planes should start being delivered about 2018. It’s amazing just how much Grumman got right with their design. Sixty years old, and it makes more sense to refurbish these planes than to attempt to convert some other or to design a new one for the role.

Grumman EF-111 Raven

2549287
EF-111s from 42nd Electronic Combat Squadron in Upper Heyford, England format off the tanker.

The Grumman EF-111 Raven was the USAF’s counterpart to the Grumman EA-6B Prowler electronic warfare aircraft. In USAF service the “Spark ‘vark”  as it’s perhaps more commonly known, replaced the EB-66 Destroyer and the EB-57 Canberra.

9-1
The Grumman EF-111 Raven first flew on 10 March 1977.

 

The first fully equipped EF-111 first flew on 10 March 1977 using a modified F-111. A grand total of 42 old F-111 airframes were produced at a cost to taxpayers of $1.5 Billion.

In terms of flight control the EF-111 (by modern standards) is pretty straight forward. As with the standard F-111,  there are no ailerons, as roll is controlled differentially by the horizontal stabilators and at low speeds spoilers on the upper surface of the variable geometry wings. Pitch is controlled by both horizontal stabilators and the rudder acts to correct adverse yaw. There are also tangential ventral fins that add to high-speed longitudinal stability.

Even though the Raven can be seen as a counterpart to the Navy’s Prowler there are some key differences.

Metric Prowler Raven
Maximum Speed (mph) 651 1460
Range (miles) 2400 (with drop tanks; usually carried) 2,000
Ceiling (ft) 37,600 45,000
Rate of climb (ft/min) 12,900 11,000
Thrust/weight ratio (lbs/ft) 0.34 0.598

These performance differences enabled the Raven to do some things operationally that the Prowler could not. The Raven could keep up with supersonic strike aircraft like the F-111 and later the F-15E in the escort strike role. However the Raven doesn’t have the endurance that the Prowler had because of a few factors. The Raven has a crew of 2, limiting the crew tasking loading for a given mission. The Prowler has a crew of 4 enabling more tasks to be spread to more crew members. The Raven uses “flying boom” method for aerial refueling which limits the tanker aircraft to refuel the aircraft to USAF-only tanking assets. The Prowler had the ability for fire the AGM-88 HARM (High Speed Anti-Radiation Missile) while the Raven did not.

800px-AGM-88E_HARM_p1230047Both aircraft did use the AN/ALQ-99 Tactical Jamming System (TJS). The Raven specifically used the AN/ALQ-99E variant which had more automation for the 2 crew members and about 70% commonality with the Prowlers TJS (at least the earlier versions of the TJS).

The EF-111 houses components of the AN/ALQ-99E within the aircraft. The most visible changes to the EF-111 are the “canoe” in the ventral fuselage (that replaced the PAVE TACK pod in the F-111 variants, the “football” atop the vertical stabalitor, and an antenna on each wing glove for the ALQ-137 low/mid/high band reciever (port) and the ALR-62 forward RWR (starboard).

66-056 Tail
Components of the AN/ALQ-99E are seen on the “football” atop the vertical tail.
EF111s
This EF-111 show the ventral “canoe” fairing stowing the components of the AN/ALQ-99E TJS. The bullet fairing top is the AN/ALQ-137 multi-band receiver.

 

ef111ravencutaway
EF-111 cutaway. Click to embiggenify.

 

Operationally, the first EF-111s were deployed in November 1981 to the 388th Tactical Electronic Squadron, Mountain Home AFB, Idaho. From 1984 to 1992 the –111 saw service with the 42nd Electronic Combat Squadron (part of the 20 Tactical Fighter Wing) at RAF Upper Heyford, UK. The –111 also saw service with the 27th Fighter Wing at Cannon AFB in the 429th (1992-1998) and the 430th (1992-1993) Electronic Combat Squadrons. Also at Mountain Home AFB with the 388th (1981-1982) and the 390th (1982-1992) Electronic Combat Squadrons.

The EF-111 first saw combat with the 20th TFW as part of Operation El Dorado Canyon against Libya in 1986. Then during Operation Just Cause in Panama in 1989.

The largest EF-111 deployment for the EF-111 was Operation Desert Storm. The 18 EF-111s in the AOR flew over 900 sorties with a mission capable rate of 87.5 % mission capable rate. EF-1111 frequently operated with the F-4G and because the Iraqis feared the F-4G and its HARM missile, they made brief, limited and ineffective use of their radars. When they did choose to operate these radars, the effective jamming of the EF-111 negated their ability to track, acquire, and target attacking aircraft. Every day the Weasels and Ravens supported shooters as they attacked their targets in Iraq and the Kuwaiti Theater of Operations (KTO). One sign of their success was that after day four, all allied aircraft operated with impunity in the mid to high altitude environment across the AOR. By decreasing the threat of SAMs to our strike aircraft, EF-111s and F-4Gs permitted aircraft to deliver their weapons from an environment where they can be very lethal.

A notable event was a “maneuver” kill by an EF-111 of an Iraqi Air Force Mirage F-1EQ on the opening night of Desert Storm:

On the first night of the war, Captain Brent Brandon was flying his EF-111 “Spark Vark” on an electronic warfare mission ahead of a group of jets on a bombing run. Several IRAF Dassault Mirage F1s came in and engaged the flight. One of them went after the unarmed EF-111. Captain Brandon executed a tight turn and launched chaff to avoid the missiles being fired by the Mirage. A F-15 on the same flight, piloted by Robert Graeter, went after the Mirage trying to protect the EF-111. The Mirage launched a missile which the Raven avoided by launching chaff. Captain Brandon decided to head for the deck to try to evade his pursuer. As he went down he pulled up to avoid the ground, the Mirage followed him through, though the Mirage went straight into the ground. An unarmed EF-111 thus scored an air-air victory against a Dassault Mirage F1, although Graeter was credited with a kill. The EF-111A pilots won the Distinguished Flying Cross

An Iraqi Air Force Mirage F-1EQ.
An Iraqi Air Force Mirage F-1EQ.

The aircraft was EF-111 66-0016 and is on display at the Cannon AFB Museum:

EF-111 66-0016 on outside display at Cannon AFB New Mexico.
EF-111 66-0016 on outside display at Cannon AFB New Mexico.

There was one combat loss of the EF-111 during Desert Storm:

On 13 February 1991, EF-111A, AF Ser. No. 66-0023, callsign Ratchet 75, crashed[11] into terrain while maneuvering to evade a perceived enemy aircraft threat killing the pilot, Capt Douglas L. Bradt, and the EWO, Capt Paul R. Eichenlaub

After Desert Storm the F-111 also flew missions in Operation Provide Comfort,Operation Northern Watch and Operation Southern Watch.

The victory from Desert Storm was shoret lived. The last deployment of the Spark ‘vark was 1998 to Prince Sultan Air Base in Saudi Arablia. Due to the aircraft’s age the USAF decided to retire the aircraft and the last EF-111s were retired on 2 May 1998, at Cannon AFB, New Mexico.

Aside from the EC-130, and the later “acquisition” (if you will) of the Prowler, the USAF pretty much ignored tactical electronic warfare. You can pick up that part of the story here.

 

EF-111 retied at AMARG.
EF-111 retired at AMARG.