WACO Hadrian (CG-4) Towed Military Transport Glider
The WACO Hadrian towed glider proved one of the more important glider types for the Allies during World War 2.
Authored By JR Potts, AUS 173d AB; Content ©www.MilitaryFactory.com
A new aerial war tactic was developed in World War 2 called "vertical envelopment" in which paratroopers dropped behind enemy lines near key positions and were followed by gliders carrying additional troops, JEEPs, howitzers, ammunition, food, and other war supplies. The idea was to overtake the enemy by a surprise action while utilizing an adequately equipped fighting force to hold territory until the arrival of the main ground force. The Germans exacted such precision assaults against enemy-held areas in their takeover of Europe and the Americans studied the results with keen interest. For the U.S. Army, the concept gained considerable steam in 1941 and the initiative called for a troop- and cargo-carrying glider as a result.
The Army received designs from no fewer than sixteen companies vying for the potentially lucrative military contract. The requirements stated two distinct glider forms, the first being an 8- or 9-passenger glider with the second being a dimensionally larger 15-seat model. After review of all of the received material, the Army ordered prototypes from eight entries including those from Waco Aircraft Company. After evaluation, Army authorities selected the larger Waco design seating fifteen as the "XCG-4".
After trials during 1942, plans were evolved for large scale production in which eventually sixteen different assembly lines from different companies around the United States participated in manufacturing the finalized Waco "CG-4A". Waco alone produced 1,075 of their product both all participants were surpassed by Ford Motor Company which produced 4,190 gliders thanks to their established mass production efforts. Its entire Kingsford facility - once committed to the building of family station wagons - was now converted to glider production with 4,500 employees working around-the-clock in eight-hour shifts and turning out about eight gliders per day.
Due to the difficult shipping process, Ford streamlined delivery of their finished gliders by cutting a 120 foot-wide, one mile path through nearby woods from its assembly line plant to the airport in Kingsford. Assembled gliders were pulled by tractor from the facility directly to the airport for transport to Army sites around the country. Ford's production process allowed the lowest procurement cost of all Waco glider builders - $15,400 each as most other builders charged a minimum of $25,000-plus for each aircraft. Military inspectors reviewed each CG-4A after final assembly to which then the gliders were disassembled, crated, and transport by rail to glider training schools. The plants involved outputted a combined 13,906 operational gliders by war's end for the U.S. Army and its allies.
As finalized, the CG-4A featured a wingspan of 83.6 feet and an overall length of 48 feet. The aircraft's frame was constructed of hollow tubular steel to help reduce overall weight and then covered over in a canvas skin process. The wings were of plywood and the floor of honeycombed plywood - a construction technique providing strength with minimal weight. The load bearing capacity of the floor enabled a CG-4A glider to carry 4,060 pounds, yielding an ultimate gross weight of 7,500lbs which was 620lbs more than the empty weight of the glider itself. In extreme circumstances, the aircraft could be loaded up to a maximum weight of 9,000lbs. It was designed for a maximum towing speed of 150mph though, in practice, it was typically towed at slower speeds of 110- to 130-mph.
The normal glide descent speed was 72 mph under perfect conditions, slowing to a standard landing speed of about 60 mph. If the plane slowed to 49 mph in-flight, she would stall and, without power, she could not recover and would crash. The CG-4A was designed with a high-wing structure on a box-shaped fuselage and a nose section that was hinged behind the two-seat cockpit. The nose could be tilted up by the troops once they disembarked, creating a 5x6 foot opening, enough to clear a JEEP or other cargo could for unloading from the main compartment. This made it possible to quickly load and unload the glider.
As required by the original Army specification, the CG-4A could accommodate fifteen fully-equipped troops which included the two pilots. Types of cargo commonly loaded were: 1 x 1/4 ton JEEP designed to carry varied equipment and weaponry plus three men, 1 x 75mm howitzer along with 25 projectiles and its two artillerymen, or 1 x Bulldozer with its sole operator. Some "reverse logistics" flights were needed from a combat area back to base for casualty evacuation so the CG-4A could also fit six stretcher of wounded.
Powered aircraft were flown directly overseas or carried on the decks of aircraft carriers, ready to fly upon arriving at the intended war zone. Gliders, on the other hand, had to be shipped unassembled in crates to which a sole CG-4A glider required five large crates needed for its final construction. Upon reaching their destinations, the wooden crates were unloaded from the holds of cargo ships over the course of days and the components were removed. Precise reassembly was required which forced specialized training and delayed delivery of many gliders during key points in the war - in turn delaying major operations. Reassembly times varied based on the familiarity held by the builders - hastily-built gliders were known to break up in flight due to sloppy building and fastening.
The gliders were usually towed behind a twin-engine transport as in the Douglas C-47 "Skytrain" by way of a nylon rope some 350-feet long. Other transports in play became the twin-engine Curtiss C-46 "Commando" and four-engine Douglas C-54 "Skymaster". The pilot and co-pilot - seated side-by-side in the wide cockpit - were trained as glider pilots first and warfighters second. Some held previous experience in powered flight training but all were a special breed who volunteered to fly the unarmed and unpowered plane without parachutes, taught to crashland their aircraft onto unknown terrain and often time behind enemy lines and under direct fire. Each glider had a simple instrument panel and only minor comforts for the crew and passenger. The crew managed the tow disconnect apparatus that separated the glider from the tow plane. The instrument panel held basics such as an airspeed indicator, altimeter, a rate-of-climb indicator, a bank-and-turn indicator, and a compass - very little of which could be controlled by the glider pilot at the mercy of his transport plane. U.S. Army General William C. Westmoreland said about glider crews:
"Every landing was a genuine do-or-die situation...it was their awesome responsibility to repeatedly risk their lives by landing in unfamiliar fields deep within enemy-held territory, often in total darkness. They were the only aviators during World War 2 who had no motors, and no second chances."
Before the D-Day invasion of Northern France in June of 1944, the Gliders were relocated to the English staging areas by way of cargo ship or towed behind bombers. During the summer of 1943, the first CG-4A made the journey towed by an American bomber while also being loaded with critical war supplies: vaccines, radios, and aircraft and engine parts. Soon, the first twenty-five gliders were in British service where they were designated as "Hadrian Mk I" and a revised-equipment model became the "Hadrian Mk II". The Hadrian name stemmed from the Roman Emperor and, as the gliders were lined up on the English tarmac, wingtip-to-wingtip, they resembled "Hadrian's Wall" - the classic 80-mile long defensive wall built across Britain to separate the "civilized" Romans from the neighboring barbarian tribes to the north.
The Glider Hazard
Back in 1942, the U.S. Army awarded extra pay of $50.00 per month to paratroopers for the inherent work hazards involved. However, glider infantry did not receive this bonus because their powerless crash landings were seen not regarded as equally dangerous as jumping out of a plane (with two parachutes no less). Glider-borne infantry, therefore, quickly developed nicknames for their wooded planes like "flying coffins", "tow target" and "silent wings". Veterans of glider flights said they were not silent at all but much louder than hell due to the glider's construction materials - simply canvas over wood - that provided next to no insulation from the roar of the tow plane's engines ahead and wind noise when traveling at 120+ mph. Couple to that was the sound of exploding enemy ground-based FlaK fire around the fuselage. The inside of the glider lacked creature comforts for the troops who sat on simple wood benches. Air pockets generated during 110- to 130-mph winds created heavy turbulence, forcing the glider to drop and rise without notice. Once near the Landing Zone (LZ), the glider would cut itself loose from the tow aircraft and immediately begin to lose altitude. The typical action then involved turning around the LZ in descent until the crash landing shook all occupants to the core. At times, the fixed undercarriage would break through the fuselage floor - such was the force of these landings - and could result in severe injuries to occupants.
Lessons Learned Over Sicily
The first operation involving a CG-4A was during the Allied invasion of Sicily in July of 1943 - "Operation Husky" - when during Operation Ladbrooke 144 of the gliders, loaded with British troops, were towed toward the their LZs near Syracuse, Sicily on July 9th. Over sixty gliders were released too early under orders from their American and British tow aircraft and this resulting in the gliders crashing into the sea resulting in 252 drowning deaths. The after-action report found the incident was not attributable to the design of the glider but a premature decision by commanders to cut the tow lines - the gliders being at the mercy of such actions.