Flying the Liberty Plane

Published: 11 November 2022

By Dorian Walker
Special to the Doughboy Foundation web site

Curtiss JN4 Trainer (left) and the DH4 Liberty Plane

DH4 image

America's entire air power in 1918 consisted of the Curtiss JN4 Trainer (left) and the DH4 Liberty Plane, the first mass produced American built tactical aircraft. Seen together here in Bowling Green, Kentucky where the non profit educational group Friends of Vintage Flight is based.

It’s been a long time coming, but we have finished our film The Liberty Plane on America’s first Warbird. Inspired by both the timeframe, our own DH4, and Peter Jackson’s, They Shall Not Grow Old, we have attempted to take audiences back to World War I.

The story of America’s first warbird, the DH-4 Liberty Plane, we found as largely unknown, yet so many innovations evolved from it. The development and history of America’s first war plane is innovative, exciting and heroic. Our film introduces the innovators, the pioneers, and the young men who flew them. Four of the six MOH’s earned by military aviators in WW1 went to DH4 air crews.  Making our film The Liberty Plane is our salute to all who flew this amazing and ground-breaking aircraft. Look for it on your local PBS station–or even better, ask for it!

The Liberty Plane poster

Legends of the Sky: The Liberty Plane, a documentary from Bowling Green filmmakers Dorian and Elaine Walker, tells the story behind the DH-4 as well as the heroic pilots who proved the plane’s worth on the battlefield and, later, back home with the nascent U.S. air mail. The film will be airing on PBS stations across the nation now and will for the next 3 years; check your local PBS station for air times. Want to see the film sooner? Call your local PBS station and request that they get the film from NETA, who provides it FREE to all PBS stations.

In the past decade I’ve been focusing on bringing the ole birds (some warbirds) back to life, both in film and on the flight line.  We still fly the 1917 Curtiss Jenny. (In fact. we flew it 22 hours cross country RT to the Selfridge AFB Air Show a month ago).  Flying a WWI-era plane in the 21st Century can in many ways be just as challenging as it was for the daring aviators Way Back Then.  So I thought you might be interested in what is involved in Flying the Liberty Plane.

Flying the Liberty Plane

Sitting in the cockpit of an early 20th century aircraft is both a privilege and a challenge. First off, you don’t jump into a DH4 without proper training.

The most popular trainer back then was the Curtiss JN4 Jenny that I have over 400 flying hours in. Although the wings are massive at over 43 feet, it is a mere 26.5 inches wide. It is the same cockpit that Charles Lindbergh, Amelia Earhart, Jimmy Doolittle and countless Americans learned to fly in over 100 years ago. To fly one of these old birds, I have found it helpful to step back in time, to imagine a world without the jet liners and city airports that today makes flying accessible to everyone.

In the day, the common attributes of an aviator, since the activity was brand new, was youth and strength. Although I’m no longer under 30 and not as fit as I was back then, I do train and work hard to keep both trim and strong. Both have served me well in my foray into early aviation.

The tractor style design, that both the Jenny and DH are, replaced the early pusher style engines that were our earliest military aircraft. Why? Because the numerous accidents experienced by those aircraft resulting in fatalities caused by crushing the aviator between the ground and the rear mounted pusher engine. The American military was about ready to give up on flight altogether until Glenn Curtiss borrowed the tractor style (engine pulls the airframe) from the Brits, incorporating it in the aircraft he and B. Dalton Thomas, a young English engineer, designed. This became the Curtiss Jenny.

Author and aviator Dorian Walker in the cockpit of the DH4 Liberty Plane with the engine running.

Why do I digress while under the topic of flying the DH4? Simple. None of these aircraft of that era had dynamic stability that we take for granted in modern flying. Simply put, the old birds had tremendous lift capability (those big long wings) countered by tremendous drag (all those thousands of feet of wires) used to hold the wings and fuselage together. And as light as these aircraft were by today’s standards, they fell from the sky very fast. All ‘lessons learned’ from those who flew back then. So to fly 100 plus year old aircraft today, one needs to understand both the aircraft and the pilot’s capabilities, strengths and weaknesses. And like any piece of machinery, either today or a century ago, once you know your capabilities and the capabilities of the machine, you can go out and have a helluva lot of fun!

Both the Jenny and the DH4 flew out of omni-directional fields in their day. Even though by modern standards the rudders look large, they are not in relation to the massive bi-plane wings, over 42 feet in length on both aircraft. The solution provided by those large square or round landing fields back then is that the aircraft always took off and landed directly into the wind. No cross wind landings were required. This must be factored into flying these aircraft today, especially if, like our Jenny, we fly cross country to Air Shows.

The art of the ground loop in the day became a skill set rather than a dreaded result as in modern aviation. It was regularly applied when having to put down in a small field surrounded by tall objects. With the unreliability of newly designed and built engines, this was a standard aerial maneuver.

Strength. There are no hydraulics of any sort in the DH4, only cables and wires all tied together through a fulcrum of pulleys. To move the twin ailerons on the DH4, eight pulleys at various fixed angles along the leading edge of the wings are tied together by two pulleys in the belly of the fuselage and a single cable over 120 feet long. To move them, the elevators controlled by 70 feet of cable and multiple pulleys as well as the rudder attached to a rudder bar requires not only strength and dexterity, but also a sense of balance and agility. Tie these all together, don’t think about it, push the throttle forward and just… Fly!


Aft view of the DH4 Liberty Plane, with author and aviator Dorian Walker in the cockpit.

Unlike the Jenny where the principal flying is performed in the rear cockpit, by either the flight instructor (student sits up front) or mail pilot (mail stored up front), the DH4 is flown from the front. Boarding the Jenny requires the aviator to mount the aircraft, much like climbing aboard a horse (the Army recruited heavily from the Cavalry), you place your left foot into the stirrup (opening on the side of the fuselage), swing your right leg high up over your shoulder (agility), step into the cockpit and on to the seat, followed by bringing your left foot in to join the right foot. Once in with both feet on the seat, you slither down into the cockpit, placing both feet on the floor behind the rudder bar. And now, you are surrounded by this 26 inches wide aeroplane.

The military DH4, on the other hand, has placed the principle responsibility of controlling the aircraft into the front cockpit, leaving the rear cockpit open for the gunner/observer. Here’s where the fun begins. Mounting the DH4 harkens back to Hollywood’s depiction of flying bombers in the second world war. The flight crews arriving at the front of their aircraft, climbing up through a hatch and flying off into unknown hazards. After the walkaround pre-flight inspection, the aviator approaches from the right hand front side, forward of the wing. Using the structure of the aircraft, the left foot steps up on the wheel axle fairing, right foot up on the massive 30 inch tire, left foot up on the forward wing walk board, stepping over drag wires, followed by right foot. Now you are provided with a very ‘civilized view’ of your cockpit, and unlike the Jenny you can step into the cockpit with grace and panache. As you step into a 19 inch wicker seat with a half back, climbing down into the 28 inch wide cockpit, you are surrounded by the latest in early 20th century technology.

But here is the thing, as you sit, ready to begin the start procedure, a massive 12 cylinder, 400 hundred horsepower Liberty engine sits just 18 inches in front of your rudder bar. Without even starting the engine you can sense the power! The Jennies flew originally with 90 horsepower OX-5engines.

“I stepped into the plane, I was shaking I was so nervous, but once it started up, I forgot about all that.” Floyd Pickrell, WW1 DH4 aviator recalled. And I can understand that. Once that magnificent 844 pound water cooled, sixteen hundred and forty nine hundred cubic inch engine fired up on all 12 cylinders, 24 rocker arms whirring to a staccato symphony, you can’t help but want to push the throttle forward and move.

There were no tail wheels in the day, just tail skids (which were used for braking action since there were no brakes then either). With all that power, you maneuver turns while taxiing on terra firma with blasts of wind created by prop wash coordinated with forward stick that allows the elevators, now in the down position, to create enough lift to take the weight off the tail. This allows the aircraft to pivot in the direction of the rudder control. Because of weight and balance restrictions, you must fly the DH4 with a minimum of 150 pounds in the rear cockpit.

DH4 in WWI

WWI DH4 getting ready to launch.

Before moving and after start up, you allow the engine to warm up. With the help of the ground crew and wheel chocks, run the engine up to check both magnetos. Remove the chocks and begin the taxi. Once you’ve taxied to your departure field, ensured the winds are off your nose, using your left hand on the throttle mounted to the side of the fuselage, your right hand on the stick pushed slightly forward to lift the tail to allow forward visibility (there is no forward visibility while on the ground until now) and your right foot positioned to counter the torque of that big, beautiful 9 foot (check inches) wooden propeller, you push the throttle full forward. The first sensation, beyond the roar and vibration of the massive engine mounted on the ash wood rails of the fuselage, is that of being a passenger on an uncontrolled, bumpy ride that is moving you fast enough to lose control, but not fast enough to lift. Even thought it seems like an eternity, we’re talking 3 to 4 seconds after moving your stick forward, which brings your tail up. Now for the first time, you can see so well that you feel hope for control over this massive aerial beast. Correcting with rudder for prop torque, balanced on your main wheels for great visibility (remember you’re sitting up front now with a magnificent view, left and right and in front of the wings) you are monitoring for lift speed. Without bombs and full fuel, the wings begin arching upward at about 35 mph.

At this point the unevenness of the ground beneath you begins to lessen and that huge engine pulls its airframe off the ground at 40-45 mph. Keeping the nose low, you build airspeed to a respectable 60-65 and begin to lift skyward. Although working all your senses and your muscles, all the roughness associated with moving the DH4 on the ground below is replaced by the glassy smoothness of just air beneath your wings. What a feeling!

After maintaining your climb at full power, 1800 rpm, and leading with the rudder bar, you begin your turn to course. Once at your cruising altitude, retard power to 1450 rpm where you can actually trim with a horizontal stabilizer trim wheel mounted on the lower left side next to the pilot. Now you’ve truly stepped back in time… as you orbit, waiting for the rest of your squadron to join your mission today… to bomb the submarine squadron pens off the coast of Belgium!


C. Dorian Walker

Dorian Walker has over 40 years of filmmaking experience, fifteen of those in Hollywood. He has directed three nationally released Motion Pictures and has been associated with numerous others. Walker has Directed/Produced documentary and reality television programming for numerous major networks and his projects have been seen across the globe. From exploring historic buildings and icons such as Independence Hall, to events such as the Kentucky Derby, Dorian has masterfully blended interviews and archives with dramatic re-enactments to bring stories to life. Most recently, Walker has focused on the history of early American Aviation in a mission to keep alive the innovation, dedication and sacrifices of those who helped developed military, commercial and personal flight. A private pilot, he currently flies an historic Curtiss JN4 Jenny.

Elaine Nogay Walker

Elaine Walker has blended careers of communications, filmmaking and public office. As a co-founder of Peridot Pictures, Walker has produced, written and edited national television programming for many major networks, produced an independent feature film and developed, produced and edited numerous documentary programs including Women of Kentucky, Secrets of the Kentucky Derby, and the Legends of the Sky films. Elaine’s interest in, and commitment to remember the sacrifices of our military veterans began with her father’s service as a decorated WWII B-17 Pilot and the military service of 8 other close family members.

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