alternatehistory.com

The Waco CG-4A was the most produced American military glider of WW2 with more than 13,000 built. It was widely used in the ETO, the MTO, the SWPA and the CBI theatres. It was a success for the most part though often with heavy losses. However my thread doesn't directly address the tactical use of the Waco in its many operations because it was good enough for its job. But it could have been better.

The CG-4A had a less than optimal design because of conflicting ideas between simplicity and complexity. The original U.S. Army specification for the design was questionable as they insisted on a flapless wing design for the sake of cheapness and simplicity of construction. For a troop/cargo glider landing in a rough and unprepared landing zone possibly at night it is best to reduce the touchdown speed to as low as possible. This can best be done by reducing the stall speed with flaps. Better yet by using full span flaps.

The spoilers/airbrakes fitted to the OTL Waco would slow the glider and reduce the landing run but would increase slightly the stall speed. It is not the best method for a short landing. Flaps are more effective. They reduce the stall speed while allowing a nose down steeper landing approach. The increased lift the flapped wing produces also increases the drag so the whole wing acts like an airbrake. After releasing from the tow plane the pilot would circle the landing area and when arriving at the proper distance and altitude from the desired landing spot the pilot simply lines up with the landing area and deploys full flaps and lowers the nose to maintain the correct airspeed. Just before reaching the ground the pilot raises the nose (flares) and lands with a slower touch down speed and a shorter ground run. This helps mitigate the risk and damage from rough ground in daytime and hitting obstacles in the night time.

The CG-4A could have been designed with simple trailing edge drop flaps from wing root to aileron and the ailerons linkages could have been built to droop the ailerons when the flaps are deployed. Basically full span flaps. A little bit more complex a wing structure but an increase in survivability. Also this type of landing approach is much simpler to train new pilots to do.

Another conflict between simplicity and complexity went to the complexity side with the raisable nose section of the fuselage containing the cockpit. This introduced expense and complications to the control linkages, the fuselage construction and weakened the front of the glider. The last place you would want weakened. The theory was if the jeep shifted forward during a rough landing it would lift the cockpit out of the way by a cable hooked to the rear of the jeep that was run to a lever structure on the top of the hinged cockpit section. The flaw was if you ran nose first into something solid that brought the Waco to a sudden stop with the nose jammed against the obstacle than the jeep or other heavy load would be thrown forward into the cockpit likely crushing the two pilots.

Having a full height and width door for loading and quickly unloading jeeps and other large cargo was in itself a very good idea but might there have been a better way? I think one approach would have been to redesign that nice simple but strong steel tube fuselage to feature a rear facing full width and height opening. This would mean a change in the shape of the rear fuselage to having sloped upward shape similar to a C-123 or C-130 though much smaller of course.

This simplifies the cockpit control rigging runs permitting a more conventional floor mounted aircraft type control stick. A split Y control stick is also a simpler and cheaper fitting than the clunky wheels and bicycle chain fixtures the Waco used. Best of all the front fuselage sides forward of the cargo hold can be acutely sloped inward to protect the pilots from cargo sliding forward in a crash landing as a jeep would wedge itself against the inward sloping fuselage short of the cockpit seats. This would make the cockpit seating a little closer together but no worse than a C-47. This would also make for a more robust nose section. A good thing when landing at night without the benefit of night vision goggles.

You would not need a proper door for this rear loading Waco. It's only about 6 feet by 5 feet. A shaped bit of press board to act as a fairing to reduce slipstream drag is good enough. It can be booted out of the way easily enough if the fairing release jams. A bit of sturdy webbing across the inside rear gap protects the troops if there is heavy turbulence as the lightly built fairing wouldn't resist a soldier's weight. This webbing is simply hooked onto the steel tubing and can be easily unhooked allowing a quick exit.

A redesigned tail without a tail wheel needs a different landing gear arrangement. I would do away with wheels for landing altogether. A pair of skids running almost full length from under the cargo bay and sloping up under the nose is better for rough field landings. The rear part of the skids just aft of the centre of gravity would have small corrugations one inch wide looking similar to a vegetable grater so as to increase the braking action by scraping against the ground. These corrugations would only be on the rear part of the skids behind the C of G because if they were fitted to the front part of the skids too they might flip the glider over on its' back if they dug into the ground.

For takeoff we need wheels. A pair of axle less wheels fitted to each side of the fuselage near the C of G so the pilot can balance on the wheels during the takeoff run. If the glider is loaded correctly the nose would only be resting very lightly on the corrugation less front skids which would not impede a quick acceleration to a speed where the glider can be balanced on its' two double wheels for the majority of the takeoff run.

I don't know if the wheels should be designed as jettisonable after take off or built as to be raised up above the level of the landing skids for an assault landing. It might be nice to have the option of making a wheeled landing providing one allows for a long landing roll-out. The wheels would be raised by some simple lock and lever mechanism operated by a soldier or one of the pilots can go back to the cargo area to raise the wheels for a skid landing.

This redesign for the Waco CG-4A glider or something similar to it therefore incorporates a more complex but more effective wing to improve survivability in an assault landing. A simpler but stronger front fuselage with rear loading/unloading that simplifies the control fittings and also better protects the two pilots during an assault landing. And the improved landing gear that uses full length landing skids for faster braking and to beef up the protection from obstacles puncturing the belly and lower nose of the glider.

I think these expendable aircraft could have been better optimized for their main job of assault landings and no features complex or otherwise added unless it directly benefitted the main purpose of the glider.
Top