Monday, August 17, 2015

Pilot Report: Flying the KC-135A Stratotanker



Water Injected Takeoff


I graduated from the Air Force's Undergraduate Pilot Training (UPT) program in December of 1982 at Reese Air Force Base in Lubbock, Texas. Pinning on my silver wings was one of the proudest moments of my life. My parents, siblings and grandfather all flew out for the event. At that point I already knew that my next assignment was going to be a KC-135 tanker based in Okinawa, Japan.

Getting assigned to the KC-135 was slightly bittersweet as I, like all 22 year old aspiring military pilots, wanted to fly a fighter. Actually, not everyone wanted fighters, but at the time, such a desire seemed downright odd. Why wouldn't you? Afterburners, Ray Ban glasses, girls, G-suits, Corvettes, girls, big watches, girls, etc.

Well as it turned out, in my class of thirty or so students, there were only five fighter assignments available. And while I was good and had never "hooked" or failed a ride, I wasn't in the top five so my destiny was to fly a "heavy".

Armed with the knowledge that flying a heavy lay in my future, I decided to at least have an adventure at whatever base I was to be assigned and checked the box marked "overseas volunteer" on my dream sheet. A dream sheet was the form where you'd list your preferences for aircraft and base.

Normally I suppose the drones moling about at the personnel assignment command would get a good chuckle out of those dream sheets as they were tossed into the trash and your all expense paid trip to Minot, North Dakota was arranged. The assignment gods, however, took pity on me and I got my posting to Okinawa, a smallish island in the Ryukyu chain about 1300 miles south of Tokyo. There was once a battle there you may have heard about.

My next stop was Castle AFB, in Merced, California where I would spend three months checking out on the KC-135 as a new copilot. This was followed by a week or so in Spokane for survival and resistance training before catching the Flying Tiger 747 "Freedom Bird" from Oakland to Okinawa.

The First All Jet Tanker


The KC-135 Stratotanker, produced between the years of 1956 and 1965, was a derivative of Boeing's test bed aircraft, the 367-80. From this early test aircraft, both the KC-135 and 707 were derived which is why the KC-135 has a strong resemblance to the 707, though the tanker was smaller and lighter. Still, the tanker could carry 135,000 lbs of fuel and weighed in at just under 300,000 lbs fully loaded.

Part of the impetus for the Air Force to acquire this aircraft was the cold war. The nuclear arms race was in full swing in the late '50s and the Air Force wanted to have a tanker which could refuel its new intercontinental bomber, the B-52, to allow it to reach Russia. The old KC-97, a derivative of the WWII era B-29, just wasn't up to the task.

In fact, because the angst of quickly fielding a nuclear deterrent was so high during that time, several compromises and shortcuts were made in the design of the KC-135 to get it operational faster. These were compromises which I came to despise acutely nearly thirty years later.

The first compromise was the engines. Engine manufacturer Pratt and Whitney was working on a new engine design at the time known as the bypass fan engine. This new engine was to become the basis for all modern engines and was eventually used on the 707, but it just wasn't going to be ready in time for the tanker. So the KC-135 was outfitted with older engines which incorporated a technology known as water injection to produce enough thrust. Yes, you heard that right...they pumped water into the engine.

Without getting too detailed, high pressure pumps injected water into the engines during takeoff which increased thrust by means of an increased mass flow rate. Still, the airplane was grossly underpowered. While the airplane did usually get airborne, it would take most of the runway to do so when heavy. I have seen the departure end of the runway coming under the nose during rotation more times than I care to remember.

To give you an idea of how puny the engines were, the CFM-56 engines fitted on a 737 today produce about 34,000 lbs of thrust while the tanker's original P&W J-57s produced a mere 12,000 lbs. Due to it's underpowered nature, the aircraft gathered unflattering monikers such as "The Silver Sow" or "The Steam Jet". My personal favorite was "Strato-Bladder" for the bladder type fuel cells in the body tanks.

The KC-135A was eventually re-engined in the 1980s with those same CFM engines and was redesignated the KC-135R. The new "R" models are quite sporty now and even hold some time to climb records for transport category aircraft.

This first compromise of using water injected engines led to the compromise which I came to hate the most. To feed the water injection system, a water tank was needed. Since most of the body of the aircraft where cargo bins are on a normal plane were taken up with fuel tanks, a decision was made to remove one of the two air conditioning units, or packs. This meant that the airplane was hot, and I don't mean hot as in cool, but rather hot as in fetid.

I was stationed in Okinawa, remember, which is in a subtropical climate zone. This means warm and damp winters followed by hot and damp summers. The lack of A/C on the aircraft was most pronounced when flying hour after hour of "transition" training, or touch and go practice. It wasn't uncommon to get off the airplane soaking wet. Boeing didn't even have the courtesy to install an air vent to blow on the pilots' faces. The air outlets were under the seat where what little cool air that did emanate did no one any good at all.

Old Technology


As I flew the airplane in the early 80s, it had undergone a number of technology updates to its original systems but many vestiges of older technology were still on board. We still had a navigator assigned to the crew, but he had at his disposal an inertial navigation system, or INS which made his job more or less obsolete. Airliners were crossing oceans then with similar systems which had their accuracy measured in yards while GPS was still on the design table.

The aircraft also had, however, a sextant and an overhead port with which to view the stars. Celestial navigation dates back to the time of Magellan and was the reason the navigators were still on board. Remember, this aircraft was designed to fight a nuclear war and at the time it was thought that a nuclear detonation might render all electronics useless. Therefore, the navigator was trained to use the ancient technology of celestial navigation with a sextant to determine our course while flying to nuclear armageddon. My one regret is never having had our nav teach me how to shoot the stars with the sextant.

Over-water communications were also rather dated. While we had a high frequency or HF radio which could bounce signals long distances, ours was an old tube-type radio requiring a warmup and without a squelch control. This meant maintaining a "listening watch" on air traffic control frequencies which were always full of static, whistles and pops. Of course this was a copilot duty. When the air traffic frequencies became too unusable, I might have inadvertently tuned the radio to an awesome rock station beamed out of Saipan.

The standard for overseas communications is through the use of satellites today.

Flying the Beast


As I mentioned above, the airplane was underpowered. This meant that it had to be flown very smoothly and deliberately when it was heavy, which was most of the time. There were restrictions on the angle of bank that one could use after takeoff for instance, and multiple warnings concerning what to do or not do should an engine fail on takeoff.

There were so many red warnings on the engine failure pages that I think most of us flying the beast were convinced that an engine failure was pretty much game over. Thankfully I never got the opportunity to test out that proposition.

Once you got the airplane away from the ground and up to altitude, it really flew quite nicely. The autopilot was primitive and rudimentary by today's standards but it did its job well enough. We'd use standard airways navigation when in range of land or the navigator would feed us headings to fly when out over the water.

The actual aerial refueling process could get quite busy. Getting two airplanes together could be a challenge, especially in the weather. F-15s were easy as they had such a good radar that they always found us (and we had the gas). F-4s were hopeless, and Marine F-4s were a disaster. My job as copilot was to talk to air traffic control while operating the pumps to offload fuel to the receiver aircraft. I was also in charge of keeping our own weight and balance within limits by moving fuel around with pumps and valves. 

Refueling large aircraft such as the C-5 took special care. That aircraft had such a large bow wave that it would actually push the tail of the tanker around. On occasion, the forces might be too much for the autopilot which might click off without warning. One of us always had to be ready to grab the controls in that event.


Sushi for the inflight meal?

In the Pattern


Once we got back from a refueling mission, we might spend some time in the pattern or there might be times when we just launched a sortie with the express purpose of only flying practice approaches. There was a simulator on Okinawa but it was a sad affair with no motion or visuals and wasn't suited for actual flight training as are modern sims.

The tanker behaved reasonably well in the pattern when the weather was not very gusty. In gusty conditions, however, she became quite a handful. The reason for this is the aircraft had some very rudimentary flight controls. If you've ever wondered why fighters have a "stick", and large aircraft have a "yoke" or two handled control wheel, it's because two hands were needed to control large airplanes.

Nearly all modern large airplanes are now equipped with hydraulic flight controls. That means hydraulically powered actuators move the flight controls which control the airplane in flight. Think of the power steering on your car. The KC-135, however, had only cable and pulley flight controls. Moving the control wheel physically pulled cables running directly to the wings. This made the controls less effective and at times sluggish, especially in gusty conditions. We joked that it was a true "fly by wire" flight control system.

One of our pilots had a bad experience with this facet of the airplane. I just remember being out windsurfing that day in some truly righteous surf and north winds. Unfortunately, one of our pilots did not negotiate the crosswind landing and allowed her upwind wing to rise causing the downwind engine to strike the runway and catch fire. They landed safely, but I don't think she flew again, at least on Okinawa.

All Things Strato


As I look back on my time flying the KC-135, I don't think I appreciated what a piece of history it represented in its technology as part of the vanguard of the jet age, or its role in both the cold war and Vietnam. It has been said that during the Vietnam era, a tanker "driver" could not buy a drink in the bar as appreciative fighter pilots returning on fumes from the North would want to thank them for them being there with some gas to get them home. The motto of my squadron, the 909th AREFS, was in fact "Always There". 

Nonetheless, being stationed overseas flying some real world contingency missions in your early 20s is an experience that I'll never forget. It was an awesome time.

I'll finish this post with a bit of guitar lore as playing guitar is another hobby of mine. As the '50s were a heady time in the post war era, Boeing came to put the prefix "strato" in front of many of its airplanes as they would cruise in the stratosphere. There was the Stratoliner (model 307), the Stratobomber (B-47), and the Stratotanker.

In 1954, a guitar builder named Leo Fender introduced a revolutionary new guitar featuring many new design elements. Having already produced guitars named the Broadcaster and the Telecaster, Fender added the strato prefix to his creation and the Stratocaster, one of the most iconic guitars ever built, went on to make rock and roll history.






1 comment:

  1. Very interesting. Probably maintained your flight record as I ran the flight records shop at Kaden on my second tour.

    ReplyDelete

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