Airplanes of The Aviator

The Hughes H-1

by Walt Nowotny

All photos courtesy of Miramax Film Corp., Aero Telemetry, and Joseph Bok.

As seen in the July 2005 issue of Model Aviation.

AS FILMING BEGAN on Martin Scorsese’s Academy Award-winning movie The Aviator, he was faced with a dilemma: how to accurately portray Howard Hughes’ aircraft and the film’s flying scenes without having the original airplanes. Of those needed for the major flying sequences, one no longer existed and the other two were on permanent display in a museum, unable to fly.

Howard Hughes in the cockpit of his world-record-setting H-1B.

Digitally re-creating flying airplanes is notoriously expensive and time-consuming, and the aircraft look unrealistic even after all of the computer finishing work and digital special effects; they never convince the viewer that they are “real.” The Aviator’s executive producer Chris Brigham was frustrated by having to settle for the costly, unconvincing digital effects, so he decided to try something that had never been done: create the largest scale flying models ever built.

Howard Hughes’ aircraft needed to be reproduced and flown realistically enough to convince movie critics and viewers that the flying sequences were authentic. That may seem simple, but these airplanes needed to be so big (with wingspans of up to 30 feet) that they would be placed in the FAA experimental aircraft category.

The technical challenge fell to Unmanned Aerial Vehicle (UAV) pioneer Joseph Bok, whose company Aero Telemetry Corporation specializes in building and flying UAVs for the US military. His designs and technical innovations have been used on many unmanned airplanes that are currently in service around the world. Joe is considered by many to be the Howard Hughes of the UAV world.  

He said:  

“To pull off the effect of realism, the airplanes had to be big enough and heavy enough to fly as convincingly as a full-scale airplane. Building three scale, unmanned flying models of this size, and flying all three of them within this time frame (roughly 12 weeks) has never before been attempted by anyone within a military or commercial aerospace entity—ever. Only the recent advances in technology implemented by skilled and experienced engineers could have pulled this off.”

Joe Bock with his 1/4-scale H-1B. It was used as a motion-control example to convince Martin Scorsese that using flying models instead of computer-generated models would be better. Eugene Garcia photo.

Working at their Southern California facility, Joe and his team of 35 aerospace engineers and technicians put all their know-how and physical might into constructing several huge flyable models and motion-control miniatures. They did so relying only on old drawings and pictures from museum archives.

Aero Telemetry’s senior engineer and crew chief Darrel Hofmann said:

“The XF-11 reconnaissance airplane, the H-4 Hercules [Spruce Goose], and the H-1B racer were all built by the Hughes Aircraft Company in the 1930s and 1940s, when aviation was still in its infancy. Hughes was a real aviation pioneer. He hired the best engineers in the world at the time and spoke directly with the leading aviation experts of the time.

“He personally had a say in the design of the airplanes and he most certainly took on the tremendous personal responsibility of flying several of them for the first time as the test pilot. This attests to the man’s skill in the cockpit.”

Aero Telemetry designed major H-1 structures—such as the retractable landing-gear system—in Solid Works.

Another view of H-1 landing gear designed in Solid Works. Lack of wing thickness had to be accommodated in the plans.

Joe noted:  

“Howard Hughes himself had an extremely difficult time with the real airplanes and was nearly killed in two of them while flying. Although historians have been unkind to some of his airplane designs [the XF-11 and Spruce Goose are prominently featured in a comprehensive aerospace reference titled The World’s Worst Airplanes], I have become quite fond of both the XF-11 and H-4.

“Having studied them this closely I have come to see the subtle genius in each of the airplane’s designs. However, it was those particular design constraints that significantly impact any attempt to successfully build and fly a large-scale replica of them.

“This meant I had to come up with a design that could fly very stable and provide a degree of safety with respect to low landing speeds and controllability.”

Joe as chief aerodynamicist and Darrel as senior engineer set to work perfecting an airfoil design that would do the trick.

“For safety’s sake, Joe and I designed an airfoil with a significant tolerance for heavy airframe weight and minimized the onset of any tendency to tip stall,” said Darrel. “The airplanes had to be built so quickly that they would have to forego the benefit of many standard weight-saving manufacturing techniques that would have otherwise been applied, and therefore we knew we would have a reasonably high wing loading going in.”

“We concentrated on high-Reynolds number airfoils that tend to have lower airspeed envelopes but tremendous coefficients of lift,” added Joe.

Behind the scenes, Chris Brigham was busy negotiating with Jim Wright of Cottage Grove, Oregon, to use his newly built, $2 million, full-scale H-1B racer. Jim had painstakingly replicated the aircraft and had just finished preparations to attend EAA AirVenture—the premier aviation event at Oshkosh, Wisconsin. He was slated to fly his airplane for the movie cameras when he returned in September.

As the Aero Telemetry design-team members were settling into their respective responsibilities on the XF-11 and the H-4, tragedy struck. On August 4, 2003, Jim Wright was killed while flying his H-1B back from the Oshkosh event.

Stranger still, the propeller governor problem that caused Howard Hughes to make an emergency landing at Mines Field (Los Angeles International Airport) almost 75 years earlier contributed to Jim’s airplane’s demise. His death and subsequent loss of a fine aviator and airplane cast a long shadow on The Aviator cast and crew and on Joe’s team.

During the following weeks, a meeting was held at The Aviator and it was decided to call on Joe and his team to see if they could pull off a miracle and come up with a 1/2-scale H-1B in less than 10 weeks! Joe still had to build and fly the XF-11 and the H-4 by the last week of October—less than eight weeks away!

After a lengthy conversation, Joe agreed to the challenge; he felt that with the addition of veteran aerospace machinist John Keefe and highly touted hydraulics engineer Butch Fleck, his group could handle the heavy load. The Aero Telemetry design and manufacturing teams were split into two groups, which had multiple responsibilities, and two more complete shifts of laborers.

“Because of the additional film scheduling issues, The Aviator required that the H-1 be the first airplane to fly, even though it was the last airplane ordered,” said Joe.  

His airplane shop needed to run from 6 a.m. until midnight, seven days a week, to get the job done.

“The engineering design room was moved closer to the CNC machines so we could keep closer track of the parts and tolerances as they came off the line,” said Darrel.  

John Keefe kept the CNC milling machines and lathes running at maximum output to keep up with all of the custom-built aluminum parts required for all of the airplanes. Joe’s engineering design team began to close the gap between untested computer drawings of parts and functional working aerospace machinery on the XF-11 and H-1.

“It was an amazing process to be a part of,” said Joe. “We would come with an idea on the back of a napkin and have it designed, built, and integrated within days of its conception … it was simply amazing.”

The initial plan called for a radio-controlled model that was half the scale of the original H-1. It had to take off under its own power and fly at distances of up to three to five miles while performing numerous flight maneuvers.

The H-1B designed and built from old Hughes drawings begins to take shape.

It would require custom hydraulic retractable main landing gear (which had to be designed from scratch, built, tested, and fully operational in eight weeks). Because of the model’s sheer size, the weight of the hydraulic and electrical systems, and budget and schedule constraints (which have an impact on building options), it was anticipated that the airplane could weigh more than 400 pounds.

Heavy use of composite technology borrowed from years of working with the US military on classified projects would help the team build the airplanes quickly, yet still provide a high degree of strength in the structure. Within four weeks the H-1 began to look like a formidable machine.

Construction and Design: Many daunting design issues had to be addressed for the three airplanes. Each would be radically different from the others and would have different engines and complex control systems.

Because of the compressed schedule, it was decided to make the racer’s fuselage from foam blocks designed in Solid Works. It would be finish-sanded by Aero Telemetry’s talented “surfboard sanders” led by Jon Neill and Ian Stevenson. The finished fuselage would then be covered in fiberglass and painstakingly finished with strips of aluminum tape to give it the “flush rivet metal” look.

Ian Stevenson checks fuselage straightness. Airframe accuracy was of prime importance for historical and aerodynamic reasons.

The wing was constructed using conventional wing-building techniques, with the exception of including the new Aero Telemetry 28VDC hydraulically actuated, fully retractable landing-gear system for medium-endurance tactical UAVs.  

Darrel said:

“Fundamentally, in order for an airplane to fly, it must be balanced precisely at its center of gravity, or CG. This was the single most difficult task for the H-1 racer design and necessarily became the most critical issue.

“The ultralong tail moment about the CG and center of pressure on the bottom of the wing coupled with the huge chord of the H-1 made the airplane severely out of balance (aft CG condition) right on the drawing board. The hard part was that we had to make it look exactly scale.”

To solve the problem quickly, Joe and his crew had to design a complex yet coordinated wing and fuselage design that would place the maximum amount of weight and components in the forward section of the airplane, which was already cramped.

“Also, due to the thin airfoil thickness at the main spar and wing root where the landing gear attach points needed to be, extra consideration had to be given to the length of the landing gear, hydraulic-system location, and ground-clearance issues due to the large-diameter propeller,” remarked Joe, a former linebacker who has a bachelor’s degree in aerospace engineering and a master’s degree in engineering management from the University of Southern California. While there he studied under the auspices of renowned aerodynamicist Professor R.F. Blackwelder.

Joe Bok checks the H-1 hydraulic system’s operation on one of the massive retractable landing-gear units.

“This project required a substantial amount of aerospace engineering and a very practical application of mathematics, especially during the design phase of all three airplanes,” according to Joe.

While the H-1 was being finished and prepared for its all-important film debut, work on the ultracomplex XF-11 was progressing at a blistering pace. Critical engine and propeller testing for both models commenced at approximately the same time.  

Aero Telemetry’s engine instrumentation engineer Kenny Schaefer said:

“For about three weeks, all throughout the day we were blasted from our daily routine by the powerful engine test runs in the testing area next to the shop. They had the high-compression engines running as well as could be expected and then they were modified further by us and tuned for maximum output by Joe [Bok] and John [Keefe].”  

Joe Bok (R) and John Keefe tune the heavily modified 360cc engine with the in-flight adjustable propeller.

The group tried different types of fuel and varying ratios of fuel and oil until the right combination provided the required horsepower at a safe cylinder-head temperature. Integration of the Aero Telemetry AT-DRV-3000 Telemetry and Data Acquisition System would later substantiate the preliminary ground-test data with actual airborne-test data.  

Roger Thornton and John Keefe hold on tight as the big engine is run up and tested in the H-1 airframe.

Between the deafening engine test runs and the scream of hydraulic pumps throughout the shop, Aero Telemetry’s scale-detail expert Adam Gelbart and the rest of the team were putting the finishing touches on the airplanes coming down the production line.  

“These airplanes were being used for close-up film-camera work, so we had to make the airplanes look as good as they flew,” said Adam.  

By October 25—the week originally scheduled for filming the H-1B—the fires in Los Angeles had decimated The Aviator set, rendering it unusable. The accompanying heavy smoke made it almost impossible to breathe, much less film, so all outside shots were postponed for two weeks. This break in the action gave Joe and his team the respite they sorely needed to continue.  

They performed static load testing and CG tests, and the final finishing touches were added to the H-1’s cowl and fuselage. The engine, hydraulics, linear servo controls, Aero’s onboard telemetry system, and fuel-supply system were retested and secured for flight. By this time the entire crew had been working two-and-a-half shifts since September 16, and they were exhausted.

“And we hadn’t even started the flight-testing portion of the project yet!” exclaimed Joe.  

First Flight Test: November 4, 2003—the day for the H-1’s first flight—had arrived. The team was nervous, and Joe was concerned because they had been unable to test-fly the airplane first. All things considered, safety was the foremost issue.

On the flightline (L-R), Jason Somes, Darrel Hoffman, Adam Gelbart, Joe Bok, and John Keefe prepare to start the H-1 race airplane.

When the crew arrived at Santa Clarita, California’s famous Mystery Mesa (a location just north of Los Angeles, long favored by Hollywood as a unique film setting), they found a full movie set with more than 500 people milling about. Service trucks and vehicles were everywhere, and there was only a crowned dirt road for a takeoff area. Above it all, the set was directly on a windy mountaintop surrounded by extremely treacherous terrain, with no place to land in case of an in-flight emergency.  

“The area was completely untenable for aircraft, to say the least,” Joe remarked.“Any problem with a critical component on an airplane this big and fast that might cause loss of control would spell certain disaster for the airplane and probably death or serious injury to anyone if it came into the crowded film set area.”  

Besides the safety and liability issues for Joe, crashing the model was not an option at this critical point in the project. If the H-1 were to be destroyed during testing, there would be neither enough time nor resources to build another to fit into the filming schedule, and its flying scenes would be deleted from the script.

A crash at this early stage would likely result in the cancellation of the entire project, including the XF-11 and H-4 which were already under construction. The visual-effects producer indicated that if Joe failed, the other models would be too risky, expensive, and dangerous to try. So this single flight would have serious consequences for the team; everything they had worked on up to this point was at risk.

Crew performs final landing-gear check for H-1 before its first test flight.  

The combination of all these issues created such liability, pressure, and anxiety within the team that Joe declined to fly at that location and time. It was decided that a proper flight test in a safe place was needed.

The entire flight crew set off for a location roughly two hours away known as El Mirage Dry Lake, which is located closer to Edwards Air Force Base and in the high-desert area of California. The lakebed is known as one of the flattest places on earth—perfect for airplane testing.  

The crew arrived tired from the early morning at Mystery Mesa but relieved to be in a safe, remote area. After assembling the H-1, the team started final preparations for the flight. The hydraulic landing gears needed finishing adjustments, as did the big military drone engine; the altitude was roughly 2,700 feet above sea level, and increased altitude decreases engine performance.  

Aero Telemetry crew starts engine for first flight while sun sets fast in the west.

To help with the power loss, it was decided to remove the mufflers from the engine to get every last bit of power it had. Although this increased power, it made working around the running engine almost unbearable; the exhaust noise sounded more like a 20mm machine gun than an engine!

In an eerie coincidence, the in-flight adjustable-propeller-pitch mechanism was not going to cooperate. This was the same type of problem encountered by Howard Hughes (forcing his emergency landing at Mines Field) and Jim Wright (ultimately causing his crash). A temporary fix was installed, and the crew proceeded with a fixed-pitch propeller.

“We would try to keep the airplane climbing as fast as possible without over-revving the engine,” said John Keefe. “When the airplane got to a cruising altitude, the pilot could reduce power and try to see if the airplane would stay in level flight so we could get some real aerodynamic data from our H-1.”

With the major telemetry checks showing green, the only other problem was that the sun was setting fast in the west. With only minutes of good flying conditions left, Joe gave the launch signal, and the arming switches were turned on the engine, a multitude of airborne electronic systems, and the Aero Telemetry UHF uplink transmitter.

Joe Bok gives his H-1 one last bit of help as it taxis out to make its mark on history.

Except for shorter-than-scale landing gear, this photo could have been of the full-scale H-1 preparing for takeoff.

Seasoned RC pilot Jason Somes pushed the throttle forward, and, with a final push from Joe, the H-1 headed off for its date with destiny. It picked up speed, and after what seemed like forever, with the engine running at full throttle, its tail lifted and it started skyward. Cheers from the crew overpowered the sound of the engine.

Jason climbed the H-1 in a relatively flat left-hand turn that brought it back around toward the crew so they could get a visual on the landing gear and control surfaces.  

Everything looked good, so he throttled back and the airplane settled in a little, moving in an oval racetrack pattern probably within roughly a mile of the ground control.

Roger Thornton, John Keefe, and Joe Bock show the stress of the test flight.

Trim adjustments were made to the elevator for pitch stability, and it was time to retract the hydraulic landing gear. The switch was flipped, and the gear disappeared into their wheel wells perfectly.

The H-1 flew better with the gear up, but Jason was beginning to notice a considerable pitch-stability issue. Whenever he slowed the model with the engine throttle, it tried to pitch up. This is a deadly condition when combined with the over-running-propeller problem.

Joe called for more altitude, and the H-1 responded with a smooth climbout before making another pass in front of the crew. It was time to come home.

Jason lowered the landing gear on the downwind leg; as the airplane made its base turn to final approach, those present stood still and held their breath for the setup to landing. Jason leveled the wings for the final time and held the model in a nose-level attitude while reducing the engine’s power setting to the point of nearly shutting it off.

The H-1 descended quickly with the big three-blade propeller windmilling out in front, and it became deathly quiet in the desert; no one spoke as all eyes were glued to the aluminum fuselage as it flashed in front of the crew and the model began to settle into a condition known as “ground effect.” This is a buffeting that occurs as an airplane’s wing nears the ground, preventing it from touching the earth while riding on a pillow of air.

As the aircraft’s nose pitched up a few feet off the ground, a tremendous roar went up from those present. It touched down in a perfect three-point landing, skidding slightly to the right while sending up a rooster tail of dirt and sand from the fixed tail-skid assembly, signifying that the H-1 had made its way into aviation history and would live to fly again.  

With pride in his voice, Joe said:

“The pressure of the flight, its schedule, and long hours of engineering manifested themselves in some tears of joy from many of those who had just witnessed the amazing flight of the largest unmanned H-1B racer in the world.

“The flight was significant insofar as it proved many of the design innovations that we [Aero Telemetry] brought to the project that were untested up til this point by anyone in the military or commercial aerospace with respect to Unmanned Air Vehicle design and manufacture. This flight would also provide the technical basis for the innovative Aero Telemetry command and control systems to be used on the remaining two airplanes.”

Many other issues had to be addressed before the H-1 would fly for the film crews the following week. However, for all that had transpired to make this magnificent airplane come to life, this had been one of the most amazing days in scale-model aviation.  

Film Flight: At Santa Clarita on November 17, 2003, the H-1B was flown and filmed to simulate the world-speed-record attempt that Howard Hughes made in 1935 at Santa Ana, California.

Between the model’s last flight at El Mirage and the morning of the 17th, amazing things had taken place. At Aero Telemetry, a review of video and data telemetry from the test flight showed that several changes were necessary before the H-1 flew again. Those modifications had to be made quickly and could not disturb the aircraft’s paint or delicate aluminum finish.

Meanwhile, the fires in and around Los Angeles had finally come under control and it had started to rain. With the principal filming finished at Mystery Mesa, the producers bulldozed and rolled flat a perfect runway. In addition, there would be a minimal number of people in the area to minimize safety hazards during the flight.

The Aero Telemetry crew arrived in the dark at 4:30 a.m., and by 7 a.m. the engine was started and returned for the location’s altitude. After a lengthy safety meeting, the cast and crew prepared for an attempt. Two fire trucks, an ambulance, and emergency personnel stood at the ready.

Joe explained:

“We installed a new 48-inch-diameter, three-blade, in-flight adjustable propeller and was prepared to adjust it for the maximum pitch of around 54 inches when we got ready to cut the engine loose.

“The larger propeller required that the pilot take off and land the Hughes racer in the three-point position or risk the chance of hitting the prop blades on the runway. Therefore, the high angle of attack made the takeoffs and landings very nerve-racking.”

With Jason Somes back at the controls, Joe gave the order for the takeoff run; the military engine roared to life as the H-1 rolled out on its first flight of the day. The takeoff did have its issues; the model got “a little sideways” from the engine torque and huge three-blade propeller turning at a full 54 inches of pitch.

Although the runway was perfect, the airplane was so large that it was the width of the runway wingtip to wingtip. For the film effect, several old cars and trucks and vintage airfield equipment lined both sides of the runway, making it a challenge not to hit anything with the model on takeoff or landing.

The H-1 climbed out steadily, much to the amazement of the film crew and emergency personnel, who had never witnessed such a spectacle. When the airplane began its first pass over the film set in a diving left-hand turn, the roughly 200 spectators looked gripped by fascination. As the gear retracted and the airplane picked up speed, it seemed to transform into Howard Hughes flying the H-1 as he had more than 75 years ago.  

At nearly the time Jason was getting more comfortable with the airplane’s handling characteristics, it came time to land and refuel. He shot a perfect approach to the top of the mountain and three-pointed the aircraft right on the money. The several hundred film personnel and spectators cheered wildly as it settled in and slowed to a stop, using every inch of the bumpy runway.

Before the cheering had stopped, the Aero Telemetry ground crew was in action downfield, trying its best to ensure the H-1’s quick recovery and turnaround. But it was discovered that the rough runway coupled with the heavy down-force on the empennage had destroyed the tail wheel on landing.  

Crew chief Darrel Hoffman immediately set about fabricating a fully functional replacement tail-skid assembly that not only worked perfectly for maintaining directional stability for the big racer, but remained out of sight for the movie cameras during the next flight.

“There wasn’t a machine shop available out there, so it became a race with time for me to come up with a tail-skid assembly that would be functional and strong enough to withstand the weight of the airplane, and I only had about 20 minutes to do it!” he exclaimed.  

While the movie crew busily reloaded ground cameras and made final adjustments to the aerial coordinator’s helicopter film cameras for the next flight, John Keefe and Roger Thornton quickly refueled the H-1, and Joe adjusted the engine for maximum power. He said:

“1/4 turn of the high speed needle put the big drone engine at a full military power setting. For the film sequences of Howard Hughes’ world-speed-record attempt, we not only tried to re-create something very special for Martin Scorsese and Chris Brigham, but also we were attempting to own the world speed record for the fastest 1/2-scale airplane manned or unmanned, and I think we did it on this flight!

“We were clocked going downhill at somewhere around 150 knots [172 mph], and it was an utterly amazing sight to behold.”

The next flight had an escort in the sky: a manned helicopter used for aerial filming. The H-1’s three-point takeoff was perfect, and the landing gear were retracted before the airplane had even turned crosswind as it climbed out in a beautiful arc across the sky.

As the aircraft was brought out of the diving turn, the throttle was pushed full forward and the giant propeller turned at maximum pitch. The model’s incredible sound echoed throughout the canyons surrounding the set. Roger Thornton commented:

“The H-1 made an incredible sound that literally echoed throughout the canyons surrounding the set. When they brought the airplane in at full throttle through the pylons only 20 feet from the ground, it sounded like a freight train and was indistinguishable from the real thing … it just literally shook the ground around us as it flew past.”

The aircraft’s rock-steady flight characteristics, high speed, and detailed finish combined with the vintage-airfield setting at Mystery Mesa was realistic and convincing, even for the spectators. The Aviator Executive Producer Chris Brigham, who had witnessed the flight from the vantage point of the helicopter, told Joe that “the airplane was simply breathtaking to watch from up there.”

After several passes through the mock speed course, the H-1 was ready to land. Before it did, though, Joe told Jason to perform an unscripted maneuver as a fitting salute to Howard Hughes and those who were there that day to witness his H-1B’s record-setting flight.

The H-1 wings over for the cameras during a full-power, low flyby (Above) and then makes one last flyby for the hundreds of cast and crew of The Aviator.(Below) Spectacular!

As the model flew past the crew at full throttle, “the H-1 did the most beautiful slow roll you’ve ever seen,” said Joe. “Probably something that Howard would have done too. The record-setting performance of our H-1 racer was absolutely breathtaking to witness, and it was done under some of the most extreme circumstances imaginable.”

Of the day, he said:

“The incredible effort of the team during these last few weeks cannot be overstated. The airplane flew perfectly and provided the cameras with some of the most amazing aerial footage of the H-1 racer that could have only been had if Howard Hughes himself were here to do it … in some ways I really think he may have been … ”

Joe Bok (L) and John Keefe (R) tuck the H-1 racer back into its trailer after a successful film flight.