U.S. Navy Aircraft History

By Tommy H. Thomason

Thursday, March 23, 2017

The Complete and Illustrated LSO Guide and Much More

Once upon a time, I posted a brief summary of the history of Landing Signal Officers here:
http://thanlont.blogspot.com/2012/11/waving-them-aboard-lso.html (also see http://thanlont.blogspot.com/2017/01/1946-royal-navy-deck-landing-training.html).

Boom Powell, Naval Aviator and LSO, has written a much more entertaining and informative book on LSOs, published by Specialty Press:

You can read the rave reviews on Amazon here:

Tuesday, February 28, 2017

Carrier Plane Guard by Helicopter

This is a work in progress...

The carrier plane-guard role dates from the very first operation of airplanes from ships. The destroyer Roe was reportedly assigned that duty for Eugene Ely's takeoff from Birmingham on 14 December 1910.

The plane-guard ship trails and/or leads the carrier in order to be into position to heave to and lower a boat for pickup of an airplane's crew when a crash occurs. Here, an OL-8 is landing aboard the first Lexington in 1929 with the plane-guard seen maintaining station in the lower right-hand corner of the picture.
Even experienced aviators occasionally had need of rescue. Here, LCDR Lindsey, CO of VT-6, has crashed his TBD Devastator while attempting to land on Enterprise on 28 May 1942, just prior to the Battle of Midway. The plane guard, Monaghan, is maneuvering into position to launch a boat to pick up Lindsey and his crew.

What is surprising is that it took so long for the Navy to realize that the helicopter was a much better solution for plane guard. Sikorsky had already added a rescue hoist to one of its helicopters in 1944. Igor himself was one of the first to evaluate it.

On 29 November 1945, a hoist-equipped Army helicopter piloted by Sikorsky chief test pilot Dimitry D. (Jimmy) Viner and crewed by Army Captain Jackson E. Beighle was used to make a daring rescue of two crewmen in stormy conditions from a barge aground on a reef off Fairfield, Connecticut.

The Navy did buy and utilize these early helicopters immediately after the war for utility missions but these did not include plane guard. Sikorsky finally volunteered the use of one of its new, civil-registered S-51 helicopters piloted by Jimmy Viner for an at-sea trial.
His first rescue was of LT Robert A. Shields on 9 February 1947, after he had to ditch following the failure of his SB2C's engine. A second rescue was required when Viner was flying plane guard and an SB2C crashed on approach to Franklin D. Roosevelt. Two more rescues would be accomplished before the end of the month.

After that, virtually every Air Group Commander wanted an HO3S, the Navy designation for the S-51, assigned to his carrier for plane-guard duty. However, the HO3S was constrained both by payload and center of gravity limitations (its cabin was well forward of the rotor) for the role. As a result, the Navy had a competition for a bespoke plane-guard helicopter that was won by Piasecki with a variant of its two-rotor configuration. It was designated HUP.
For a hoist, the right seat was removed the hatch below it opened through which the rescue sling was lowered and the rescuee was retrieved.

The crewman stood ready to assist the rescued man into the helicopter and keep him from grabbing the engine controls on the center console.

As Alex noted in his comment below, the Kaman HUK (UH-43C) was also used occasionally for plane guard.
Its intermeshing two-rotor system provided the benefits of the twin-rotor helicopter (excellent hover efficiency and indifference to wind direction) but was much more compact.

As Alex also noted in a comment, the ASW air groups would use one or more of their helicopters for plane guard, since they could be readily equipped with the requisite hoist. This is an HO4S hovering for a pickup in a training/familiarization exercise. Note the dye marker in the water and the smoke float in the background to indicate wind direction.

When the HO4S was replaced by the HSS in the ASW helicopter squadrons, it was similarly utilized. Note the large warning to "Abandon Chute" under the cabin door.

This was dictated after a failed attempt to hoist a pilot after his parachute inadvertently deployed.
The pilot either released himself from the sling or got pulled out. He was subsequently rescued by a whaleboat from the carrier.

Even without the pull of an open parachute, the HUP was underpowered. What's worse, what power that there was provided by a former tank engine that was failure prone. The ultimate solution for the helicopter in general and the plane-guard helicopter in particular was the turbine engine. It was light relative to the piston engine and small, which allowed for the cabin to be located directly under the rotor, eliminating the center-of-gravity concern. Kaman won that competition with its first single-rotor design. It was designated the HU2K, which in 1962 was changed to H-2.
It was sleek and fast, with a retractable rescue hoist in the cowling above the cockpit. One innovation, which did not prove lasting, was a boom-deployed rescue net for scooping up a rescuee.

Although there were teething problems, these were overcome and the Seasprite eventually was powered by two engines. However, the elimination of the ASW-dedicated aircraft carriers resulted in the addition of ASW helicopters to a big carrier's air wing. Since the SH-3 came with a rescue hoist, the HS squadrons were assigned the collateral duty of plane guard, resulting in the retirement of the H-2s.

The H-3s, in turn, were eventually replaced by multi-mission Sikorsky H-60s.

Angelo Romano Photo

Wednesday, January 25, 2017

1946 Royal Navy Deck-Landing Training

"England and America are two countries divided by a common language." Before the U.S. Navy took a close look at postwar Royal Navy innovations like the steam catapult, angled deck, and mirror landing system and adopted them, it pursued a very independent course in developing aircraft carrier operations. This is a brilliant 1946 Royal Navy training film focused on the deck-landing phase of carrier flying: https://youtu.be/qxtXDDShjGs

In particular, note that the signals given by the Deck Landing Control Officer (i.e. LSO) at the time were not only very different in almost all cases, they are actually reversed in the case of the high and low signals used by the U.S. Navy LSOs. See http://thanlont.blogspot.com/2012/11/waving-them-aboard-lso.html

Most of the airplanes in the film are Corsairs:
No mention is made of difficulty landing them, although in the first landing shown, the pilot does appear to be skidding a bit in the groove to maintain sight of the DLCO.

The film also includes clips of the first jet landing (British, as were most carrier firsts) and the unusual position of the DLCO when waving the twin-engine Mosquito, necessitated by the need to not be hidden from the pilot's view by the engine nacelle:

Saturday, December 10, 2016

Horses for Courses: Intruder vs. Buccaneer

If you're familiar with both U.S. Navy and Royal Navy airplane programs from the early 1960s, you may have wondered why the former developed a bigish carrier-based, subsonic, two-seat attack airplane when the latter already had one in development, the Blackburn Buccaneer:
Via Tony Buttler

Certainly the U.S. Navy was paying close attention to the Royal Navy during the early 1950s when the Buccaneer program was initiated, as evidenced by its adoption of the steam catapult, the angled deck, and the mirror-landing system.

The answer is basically requirements. The U.S. Navy wanted a replacement for the obsolescent Douglas AD-5N Skyraider that it and the Marines used for all-weather attack and to a limited extent, antisubmarine warfare.

Some of the requirements overlapped, for example range, payload, carrier-compatibility. However, the Navy wanted to be able to find and accurately bomb a land target while the Brits had in mind a strike against ships at sea or naval bases. As a result, the Buccaneer was optimized for near-sonic speed at sea level for a survivable run-in against a heavily armed target: tandem cockpits, a small radar dish (but adequate to find a big target), an internal bomb bay, a relatively small wing, a retractable inflight refueling probe (also see comment below), and unusually for a subsonic airplane, area ruling. The Intruder, on the other hand, had not one but two radars, side-by-side seating (not a handicap given the size of the nose required for the radars) five stores pylons, a relatively high-aspect-ratio wing (required in part for the Marines desire for short takeoffs and landing ashore), etc. It was definitely not area ruled and its refueling probe was always extended.

For more on the development of U.S. Navy attack airplanes including the A-6, see my book, Strike from the Sea, available from Specialty Press or Amazon (https://www.amazon.com/Strike-Sea-Aircraft-Skyraider-1948-Present/dp/1580071325):

Note that there are other books with the same title...

Friday, September 30, 2016

The Turtle's Takeoff

Great googly moogly...

For a summary description of this Lockheed P2V's record distance flight, see http://thanlont.blogspot.com/2011/01/truculent-turtle.html

I knew the overloaded takeoff from Perth, Australia was a close-run thing, but I just came across this video recently posted by Ken Horner:


Note that for maximum takeoff benefit from JATO, you fire the rockets so that burnout occurs just after liftoff. That is why there is no JATO boost during the first part of the takeoff roll.

In the event of an engine failure at or above 1,000 feet after takeoff, the crew had a fuel-jettison plan (including getting rid of the tip tanks) to get down to a weight that would allow them to climb before they hit the ground. It doesn't look like they got to 1,000 feet for a while...

Thursday, September 29, 2016

How Hard is It to Land on an Aircraft Carrier?

U.S. Navy Mass Communication Specialist 3rd Class Tomas Compian

I was recently asked "How hard is it to land on an aircraft carrier?" I regret to say that I don't know personally. My only pilot experience in that regard is making an approach and landing a Lockheed S-3 in a Navy flight simulator. My only actual carrier landing was as self-loading freight facing backwards in the cabin of a Grumman C-2 Greyhound transport. (I can say in that case there was an unsettling amount of flight control activity and throttle changes on short final before a very firm arrival and impressively short stop.)

However, I have a lot of second-hand knowledge based on reading books/articles, an overnight stay on an aircraft carrier being used for day and night carrier qualifications, listening to naval aviators, etc. The degree of difficulty also depends on the era. In the beginning, landing speeds were much slower and crashes less dramatic, at least as far as the pilots were concerned. As airplanes got bigger and heavier, higher landing speeds were required and crashes became much more colorful. The introduction of jets reached the upper limit of practicality and the Navy was in danger of exceeding it.

The angled deck and the mirror-landing concept were adopted just in time to restore a reasonable amount of repeatability to the landing process. (The fact that carriers were getting bigger and bigger was also beneficial.) The latest automated landing systems now being qualified promise to make the carrier landing a non-event, the equivalent of the self-driving car.

For the time being, however, a carrier landing requires a high degree of precision with potentially fatal consequences for getting it wrong, similar to a high-wire circus act without a net or safety harness. The precision required is akin to flying under a low bridge, a high-risk and foolhardy maneuver. Hitting the bridge, its supports on either side, or the water is likely to be fatal.

The penalty for being too high in the event of a carrier landing is not fatal but means not being able to land on that approach. Another is required, prolonging the time the carrier has to spend on that course and potentially delaying the subsequent launch cycle.

Being a bit too far off to the left or right on a carrier landing is almost as bad as hitting the bridge supports. It risks a crash into parked airplanes on either side of the landing area and/or going off the deck into the water.
 U.S. Navy Mass Communication Specialist 3rd Class Rob Aylward

Being too low is the worst, resulting in a ramp strike. A bit too low might just mean damaging the tail hook, which requires a diversion to a shore base or a landing on the carrier using the barricade which again disrupts carrier operations. Hitting the ramp with the airplane itself is frequently fatal.

How big is the opening? About 20 feet by 20 feet. The target height for the end of the tail hook at the target angle of descent is about 14 feet above the ramp. Being only four feet or so higher means missing the last wire and having to take off again, a bolter.

The width of the opening is constrained by the imperative to keep either wingtip safely distant from the "foul line" that other airplanes and equipment are kept behind. In other words, the naval aviator can touch down as much as 10 feet on either side of the center line as long as the sideward drift, if any, is toward the center line and not away from it.

However, simple passing through the imaginary opening about 20 feet high and 20 feet wide is not sufficient. At that instant the airplane must also be traveling at the target airspeed and with the target rate of descent so as to put the tailhook on the deck between the second and third wires. Being too fast or at too shallow a rate of descent means touching down beyond the last of the four wires and boltering; too high a rate of descent, while insuring that the hook touches the deck before the last wire, risks exceeding the strength of the landing gear.
 The resulting ejection was successful.
 U.S. Navy Photographer's Mate Louis J. Cera

It helps that the target rate of descent, while high—about eight knots or nine miles per hour—is not much more than one third of the demonstrated capability of the landing gear. Landing gear strength is one of several differentiators between airplanes designed for carrier operations versus those that fly from airfields. The stronger landing gear means that the naval aviator does not have to, in fact should not, flare to decrease the rate of descent as part of the landing because not flaring increases touchdown accuracy.

It doesn't help that a lot of time is not allowed to get lined up with the opening and stabilized at the target airspeed and rate of descent. There is often a compelling reason to get all the airplanes aboard in as short a time as possible (for one thing, the carrier has to be headed into the wind for landings and that may very well not be the direction that the battle group needs to go). As a result, the time allotted for the final approach is on 15 to 18 seconds in daytime.

Moreover, unlike an opening under a bridge, the one that the naval aviator must pass through is moving. Even the biggest carriers are affected by stormy or ocean-swell conditions: depending on the sea state, a carrier can move in six different ways—pitch, roll, yaw, heave, sway, and surge—in various combinations. Although the ship movement isn’t quite random, it is not really predictable either. The current big-deck carriers, at least, don’t move quite as much as the smaller ones did.
The rate of change of a big-deck carrier from one extreme to another is also usually relatively slow. Nevertheless, under certain sea conditions, the ramp can move about 20 feet, the height of the imaginary opening, or more in only 10 seconds.

There is also the added degree of difficulty of having to fly "under the bridge" at night from time to time, with only a few lights as guidance as to the location of the opening. As a result, the final approach is then lengthened to about 25 seconds.

For dramatic video of carrier landings under those conditions, watch these:

Although the naval aviator is alone in the cockpit, he or she is assisted by the advice and counsel of a Landing Signal Officer (LSO) standing on the deck who monitors the approach and can often detect an unacceptable trend developing with it or with carrier motion before the aviator does. The LSO's command to abandon the attempt, a wave off, must be complied with.

Tom Wolf in his book, The Right Stuff, observed that test pilots and race car drivers are not preternaturally brave or foolhardy but instead have convinced themselves that they have the skill and knowledge to not crash as opposed to those who have. Prospective naval aviators go through a training program that is designed to instill that level of confidence in them. It also ruthlessly eliminates individuals potentially inadequate to the task. (For more on this, see my book, Training the Right Stuff, HERE.)

The naval aviator prowess at carrier landing continues to be closely monitored during his career by the LSOs, squadron commanders, and the Carrier Wing Commander for poor performance at sea. The result is a very low crash and casualty rate in what is widely regarded as the most demanding aviator skill, the carrier landing.