The CG-4A Glider
"The Flying Coffin"
Description:

The Waco Model NZR, better known as the CG-4A, is an externally braced high-wing monoplane of 83-feet, 8-inch span. This glider is capable of carrying a useful load of over 3500 pounds. A spacious cargo compartment is provided, which is directly accessible by raising the hinged nose section of the fuselage. This affords a clear access to the cargo compartment 72 inches wide by 65 inches high, limited only by the walls of the fuselage. Through this opening may be loaded rolling cargo, such as the U.S. Army Ford or Willys ¼ -ton truck or the U.S. Army 75mm. Howitzer. Ammunition boxes, crated engines or similar bulky cargo may also be loaded through the front of the fuselage. The cargo compartment is provided with quickly removable benches and safety belts to provide seating for 13 fully equipped troops.

The pilot’s compartment is in the nose section of the glider and seats are disposed in a side-by-side arrangement for pilot and copilot. A full set of controls are provided for each pilot with the exception of brake pedals, which are found on the left hand set of rudder pedals only. Controls consist of the conventional flight controls, trim tabs controls for all surfaces, and spoiler controls.

Construction:

The wings are rectangular in plan form and are strut braced from the fuselage. Wood and plywood construction is employed, the structure consisting of main spar, rear spar, ribs and plywood skin covering. The entire wing is covered with fabric doped directly to the plywood skin. Frize type, statically and dynamically balanced ailerons of wood construction is mounted on the wing panel through three ball bearing self-aligning hinges. Each aileron is provided with a balancing tab and the right hand aileron incorporates a controllable trim tab.

The fuselage is a rectangular welded steel tube frame, faired and covered with fabric. The cargo compartment floor is of wooden construction, and is bolted to the lower ends of the side truss members forming the closure structure for the fuselage frame. A main entrance door is located in each side of the fuselage at the rear of the cargo compartment and two triangular emergency doors are installed at the forward end. All doors are jettisonable for emergency exit.

The tail group is of wood construction with steel tube brace struts to the stabilizers and steel cables bracing the fin. All tail surfaces are fabric covered and the movable surfaces are dynamically balanced by means of lead counterweights bolted to their leading edges.

Both elevator and rudder are provided with controllable trim tabs and are hinged through self-aligning bearings.

Landing gear is of conventional type employing spring-oil shock absorbers in both the main and tail gear units. Hydraulically operated brakes are incorporated in the main gear, and the solid rudder tail wheel is of the full swiveling type with a self centering spring.

General Specifications:

Span…83ft 8in.
Length…48 ft 4-5/8 in.
Height…12 ft 7-7/16 in.

Wings:
Airfoil Section…NACA 43012
Chord…10 ft 6 in.
Incidence…0 degrees
Dihedral…1-1/2 degrees

Stabilizer:
Span…22 ft 0 in.
Chord…6 ft 0 in.
Incidence…0 degrees

Areas (Sq. Ft.):
Wing (less ailerons)…766.1
Ailerons…85.4
Stabilizer (including elevators)…114
Elevators…54.6
Elevator Trim tabs…2.42
Fin…25.10
Rudder (including Tabs)…33.57
Rudder (tab)…1.37
Aileron Trim tab….0.70
Aileron balancing tab…4.30
Spoiler…4.06

Performance (CG-4A Glider with gross weight of 7500 pounds):

Take Off:
1. Max ground roll…2750 ft
2. Max distance to clear 50 ft obstacle…4900 ft.
3. Take Off speed…85 mph

Climb:
1. Min. Tow plane indicated airspeed for climb…105 mph
2. Initial rate of climb…410 fpm
3. Service ceiling…11,300 ft
4. Time to climb to service ceiling…37 min.

Cruising (75% power):
1. Cruising altitude…5,000 ft
2. Indicated airspeed…133 mph.
3. True airspeed at 5,000 ft…150 mph.
4. Range (804 U.S. Gallons fuel)…635 miles

Maximum Range:
5. Altitude…5,000 ft
6. Indicated airspeed…105 mph.
7. True airspeed…120 mph.
8. Range (804 U.S. Gallons fuel)…870 miles

Limiting Speeds:
1. Over 7000 lbs…150 mph
2. Over 8000 lbs…143 mph
3. Over 8500 lbs…135 mph
4. Over 9000 lbs…128 mph

Stalling Speed:
At 7500 pounds gross weight, stalling speed is approximately 60 mph indicated airspeed. At sea level actual stalling speed is 48 mph.

Landing:
The glider may be safely landed at normal gross load in a field 660 ft by 200 ft surrounded by 50 foot obstacles without benefit of headwind.

Miscellaneous:
A 12-volt battery furnishes power for navigation and cockpit lights.

A 350-foot, 11/16-inch nylon rope attached to the nose of the glider is used on single tow. A 425-foot rope for the glider on the right when double towed. Nylon is used because it is strong and elastic, thereby absorbing stresses.

The CG-4A has a type A1A-1 interphone system for communication between glider and tow plane.

Information obtained from AAF Manual No. 50-17, March 1945

    


Glider Photographs
                    
                    
                    
                    
                    
                    
                    
                    
                    
                    
                    

Life Expectancy of Pilots in Combat:
Bomber Pilots. 1 hour, 46 minutes
Fighter Pilots. 19 minutes
Glider Pilots. 17 seconds