Test Piloting the DC-8
Flying - June, 1959

By A.G. Heimerdinger
Engineering Test Pilot and Flight Operations Manager, Douglas Aircraft Co.
As told to Don Downie

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YOUR COLT OUGHT to be a champion. He's got the breeding", smiled my horseman friend, as we stood at Long Beach together remarking on the lines of the number one DC-8.

He had put his finger on the character of the giant jet transport-more than a quarter of a century of great ancestors behind it-the family of DCs that had done more to open up the world than any vehicle in history; the DC-3 that authored the era of piston transports, the DC-4 that first tied together "one world"; the pressurized DC-6s that lifted commerce above the weather; the DC-7s that first introduced true transoceanic range; and now this swept-wing miracle to mark another epoch of the air age. What a happy heritage it had.

A man has a right to be proud of a part in such a progression, I had thought to myself after my friend's remark. But think of the responsibility too. Millions and millions of people will be riding this plane all over the face of the earth for the next two decades. It will be modified and given new ratios of power from time to time, just as were its predecessors. That it be inherently "right" is partly my responsibility. It's a thought to make a man sober. So when the first DC-8 lifted off the runway at Long Beach, Calif., last May 30 on its maiden flight, I knew I was carrying the basket with the golden eggs- and with $250,000,000 invested in the program to follow. It was by far the greatest thrill of my life!

We were scheduled to "leap off" at 10:00 a.m., but while Bill, Paul and I, (William M. Magruder, co-pilot and Paul H. Patten, systems operator), were making our final preflight checks, a ground fog sneaked in. It appeared that we'd be delayed. There were 50,000 spectators waiting, but our Federal Aviation Agency approval required VFR conditions with five miles visibility, so we sat and waited. The weather finally broke clear and we got off within ten minutes of our scheduled time.

We three were undoubtedly thrilling with the excitement. Each of us had spent 35 hours with the first Link DC-8 simulator at Binghamton, N. Y. and had practiced every possible emergency situation, but yet we were doing something that had never been done before. The 2:10 hour flight was without incident but it was still high adventure. After landing at Edwards Air Force Base, we all felt the big let-down that test pilots universally know.

Following take-off we headed out over the Pacific and climbed to 11,000 feet. A recon DC-7 flew in on our wing to take engineering and press pictures. We were surprised that we could hear the noise of its engines and propellers. In later test flights, when cruising near electric storms, we discovered that we could hear the sound of thunder in the cockpit. The DC-8 is just that quiet! Previous to the take-off of the DC-8 at Long Beach, all of my previous jet experience had been in T-33s and B-47s. I didn't know quite what to expect from this huge jetliner. However, its handling characteristics soon proved to me that here was a plane to tie to even among Douglas transports. It flashed through my mind-with what ease the airline pilots were going to make the transition to the DC-8.

In the first seven months of flight testing, I put 137 hours on the No. 1 DC-8. Flights averaged about three hours each and progressed from slow to high speed performance, through stalls, dives, induced flutter tests and landings with various weight distributions. Two types of flutter tests were made; high frequency flutter tested by firing charges of power equivalent to 12-gauge shotgun shells (called impulse generators) on the stabilizer tips and on the tip of the vertical fin, and lower frequencies induced on the wingtips by small movable flutter vanes. Records of the flutter oscillations were made both in the airplane and on the ground at our telemetering station. On flutter tests, the crew used shoulder straps and hard hats.

Early in the flight test program, we tried out various safety equipment. We had a tail chute on the original airplane to use for deceleration analysis and landing over-shoots. The 28-foot chute is designed to cut speed from 420 to 300 knots in 15 seconds. The first time we tried this chute in flight, we had our cameras whirling and the recorders going full speed. I pulled the release handle on the chute, braced myself for the anticipated deceleration shock-and nothing happened. I looked over at my co-pilot, shrugged and, after a few seconds he asked, "What do we do now?" Before I could answer him, the chute deployed as originally intended and the plane decelerated as expected! A thing like that can make you swallow your chewing gum.

The J-75 powered DC-8 Jetliner lifts from the runway at Long Beach Municipal Airport.

The swept-back wing of the DC-B produces a higher angle of attack on both take-off and landing than on previous transports. On take-off, one is sitting so high in the air that, once the nose comes up, one has the feeling of being already airborne. However, the pilot can feel the bogie wheels leave the ground and then hit the gear-up switch. The no-skid brakes on all four tires have a more effective stopping action than the aerodynamic drag of holding the nose up, so I try to land just short of a stall -110 knots on a lightly loaded airplane-then drop the nose almost immediately and apply the brakes.

By the time I flew the second DC-8 out of Long Beach, we had the improved jet noise suppressors installed. No. 2 was so much quieter than No. 1 that spectators standing along the runway thought the engines had been cut and that the take-off was being aborted. The No. 2 airplane, equipped with the J-75 engines, has 25 per cent more thrust than the No. 1 with the J-57 units, and broke ground in exactly 4,000 feet, even with a five-knot tailwind.

Flight development on a project of this magnitude is more a series of engineering meetings-up to four hours at a time -than it is actual flight testing. As the DC-8 program progresses, I spend nine-tenths of my time in meetings discussing our findings with engineers and planning new test applications. A typical day at Edwards AFB begins at 4:00 a.m. We fly up the day before, spend the evening in pre-flight discussions and take off at daylight when the air is calm. We may be up for as long as five and a half hours. The post flight "critique" can run far into the next evening.

Several types of chase planes from Edwards AFB were used to check on
various phases of the DC-8's test flights. Here the Jetliner dwars a T-37.

By the time the first DC-8 with the J-57 engines receives its domestic certification - sometime in October-we will have 25 units in the air and in the hands of various airlines for flight crew and ground crew familiarization. The license for the intercontinental is slated for December 1959; and the 310,000-pound Rolls Royce Conway configuration is February of 1960. The way things are going now; we might beat some of these dates. In this group of planes, we will use eight different aircraft for various phases of certification tests. Because each DC-8 costs over $5,000,000, the insurance people review the qualifications of each pilot we check out. Magruder took over as captain of No. 2 airplane and Patten as captain of No. 3. All 26 of the pilots we will need by July of this year for the program are already working for Douglas. Bill Bridgeman, for instance, will get No. 8 airplane when he returns from his current assignment in Yugoslavia. Naturally these 26 are all experienced pilots, with instrument ratings and heavy airplane time. Only half of them, however, have had jet experience.

It doesn't seem to take any longer to check out a pilot without previous jet experience than one who has had considerable of it. We take about 30 hours to check out our Engineering Pilots. It could be done in a little less time, but this is a serious business and we make sure to cover all the angles. Don Mullins, for instance, has had all his recent time in DC-6 and DC-7 aircraft. He had never set foot in a jet until he climbed into the left-hand seat of the DC-8, but he is now checking out just as rapidly as any of the pilots with plenty of jet time.

Quite a few non-company pilots from the airlines have been flying the DC-8. We first have them go through 15 hours in the simulator in Santa Monica and then put them right into the left seat of the airplane. The DC-8 cockpit is laid out so that the co-pilot has every control the pilot has except for the nose wheel steering. For ground operation, we a1ways use a wing man with a ship of this size because the pilot can't judge his distance from ladders, stands and trucks. In regular airline operation, the pilot merely follows the lines painted on the ramp.

During the first six months of testing, we stayed in the area surrounding Edwards AFB, except for a trip back to Long Beach for normal maintenance and a trip to San Francisco to show the plane to United Air Lines. On our San Francisco trip, Douglas photographers wanted a picture of the DC-8 flying over the top span of the Golden Gate Bridge. I made three passes at a conservative altitude so that the cameramen could frame the plane in the bridge span. As it worked out, there was considerable traffic on the bridge and a boat passing below to help make an interesting portrayal of modern transportation-air-land-sea.

A.G. Heimerdinger (center), flight operations manager for the Douglas Santa Monica Division; assisted by William M. Magruder, (left), copilot and Paul H. Patten, systems operator; was at the controls for first flight  of the DC-8. All three are veteran test pilots.

It takes only one cross-country trip- even a short one like the run to San Francisco-to show that present radio reporting stations are not completely adequate. We can sit at 40,000 feet, truing-out at 600 mph, and talk to airways stations 200 miles ahead. Just before our return from San Francisco, we telephoned the Santa Monica plant to rendezvous with Paul Mantz' B-25 for some photos at 11,000 feet and met him over Santa Barbara. We covered 300 miles in the time it took him to cover 80.

The problems involved in a rendezvous with a jet chase plane at high altitudes can be considerable. If the air is moist and we're laying down a contrail, it's a cinch, but in dry air we have spent more than 20 minutes in getting together. We use chase planes at Edwards to check for proper landing gear door opening and closing, hydraulic or fuel leaks that may be suspected, and for general inspection. The chase plane is exceptionally helpful in fuel dumping tests. We have a dump chute that extends below the wing and the chase plane can come in close to watch the pattern as the fuel comes out. When we are using a T-33 or some other two-place plane, we almost always have a Douglas photographer along to shoot engineering pictures. Since there are no propellers to worry about, the chase planes can fly in really close to inspect the items we request. One of the thrills we get is watching these chase planes when their job is done. We use a T-33 or T-37 on flights up to 300 knots and then switch to an F-86 or F-100 for higher speeds and altitudes. It's quite a sensation to hear and see these fighters at 35,000 feet cut in their afterburners, do a leisurely slow roll and peel off for the ground. You can always hear their afterburners cut in.

One of the ever-present problems in flight testing such an aircraft as the DC-8 is avoiding infringement of the many air space reservations that surround Edwards AFB. When I'm busy on a critical test at 40,000 feet, I just don't have time to watch all those corridors and gunnery ranges, so we have a chase plane with a military pilot aboard whose job it is to keep me out of the restricted areas. Edwards AFB is, however, the world's best place for a flight test program. "The lake" is good insurance for the aviation industry of this country in the rapid development of new aircraft. The only time we've had to shut down operations for any appreciable time was not caused primarily by weather, but by a radiation scare after an "A" bomb blast in nearby Nevada. Aside from this, the only delays we have had in flight testing have been caused while waiting for blown tires and brakes from other test aircraft to be picked up or swept from the runway.

All the flight testing on our first three airplanes has been at Edwards AFB. Number 4, however, is to be used for icing tests and is based at Long Beach. Here we have a 9,280 foot runway and, at flight test weights, are taking off in about 800 feet less than the DC-6 and DC-7. We never have to go any farther from the factory than the California-Oregon border to find ice. The Siskyous can generate all the ice we want to handle. Our deicing system is a simple cyclic hot air generator. The windshields are electrically heated and we use a. blast of hot air instead of windshield wipers. A similar system was used on the B-66.

A great deal of engineering has gone into the problem of slowing the DC-8 down for landings and in rough air. We have five spoilers on the plane, located toward the trailing edge of the wing Inboard of the engine nacelles. Three of the five are hooked mechanically to the flaps actuated with hydraulic boost. These aid the ailerons for lateral control at slow landing speeds. While it may sound old fashioned to some engineers, we still use tuft testing on the DC-8-stick short tufts of twine on the contours of the airplane with Scotch tape and photograph the patterns in flight.

There have been many pleasant surprises in the DC-8. Airplanes with sharply sweptback wings often have a "Dutch roll" characteristic. The DC-8 has 30 degrees of sweepback, yet we have never even hooked up the yaw damper which the engineers perfected. When we cut an outboard engine at cruising with our feet off the rudder, the nose swings only three or four degrees to one side.

One of the problems eliminated while testing the "8', was the injection of rocks, nuts and bolts-or what-have-you-into the lowslung air scoops. This problem is licked with a "blowaway jet" that squirts compressed engine gases on the runway directly in front of the engine intakes to clear away any foreign matter. The blow-away jet is linked to the nose-wheel and diverts its thrust back to driving the aircraft as the nose wheel oleo extends.

A lot has been conjectured about the basic design philosophy of the DC-8. By not making a full prototype, we have moved down the road several years in development. Actually, the DC-1, back in 1934, was the last serious prototype that Douglas built. The DC-8 design was made from the small components up, once the basic concept was established. There has been $43,000,000 spent on detail design of component parts alone on the DC-8!

I have been in the program from the start-helping originally with the cockpit mock-up. We tried to copy the DC-7 cockpit in many respects to make it less difficult for pilots to change over. Our component testing prior to flight was surprisingly extensive. For example we put a complete cabin section under water and ran it through 140,000 cycles at maximum pressure differential; that's equivalent to 100 years of steady flying. In another instance we fired harpoons at the fuselage, attempting to make it rip in explosive decompression. Use of titanium rip stops, however, limited the size of the puncture to a small hole which allowed pressure to leak out slowly and did not damage the structure.

In looking back on the long months already consumed in the DC-8 fight test program, I find It difficult to recall anything that was a real problem. Of course we had the cooperation of a talented group of men who have been building big transports for many years. From the standpoint of emergencies or engineering headaches, I guess you'd call it a dull program.

Chief Project Engineer Ivar Shogran says the DC-8 will be a 20-year airplane. That's quite a statement for a technical expert to make in view of the dynamic character of the aircraft business but I believe it's a well considered viewpoint. After long test experience with the plane, I feel It Is destined to go down in aviation commercial history as the memorable workhorse of the jet transport era. END

FLYING-June 1959