Memorandum for the Deputy Chief of Staff [Maj. Gen. Hugh Drum], June 18, 1938, by General Malin Craig, Army Chief of Staff

There is no doubt about the value of controlling fire of field artillery from the air. This requires rapid and accurate transmission of information from the Artillery Observer to the firing unit so that changes can be made instantly.

In the Field Artillery at Fort Sill, Oklahoma, the type of practice and instruction indicated in the foregoing is at low ebb. The planes in use are not suited for the modern work either in type or not being sufficiently up to date to keep abreast of the times.

I would like for the Chief of the Air Corps to concentrate upon this subject, not only at Fort Sill but at Fort Bragg and after that wherever the Air Service is working in conjunction with ground troops, with a view to obtaining speedily and making available modern planes suitable for the purpose.


Letter to Adjutant General, July 15, 1940, from Fred C. Wallace, Colonel, Field Artillery, for Maj. Gen. Robert M. Danford

This letter presents a brief discussion of the problem of air observation for Field Artillery and recommendations as to the proper organization of observation aviation considered essential for Field Artillery.

The Field Artillery is primarily interested in an airplane that can be used for the observation (surveillance and adjustment) of artillery fire. Reconnaissance and liaison missions are considered of secondary importance in so far as the employment of field artillery observation aviation is concerned and will not be discussed herein.

Suitable observation posts in average terrain for the surveillance and adjustment of artillery fires can seldom be found from which targets of importance to the Infantry or Cavalry can be located. Artillery observers who push forward with front line units have but limited perspective and are invariably concerned with the problems of their immediate fronts. In the defiladed areas in rear of the hostile lines targets (hostile troop concentrations, counterattacks forming, artillery batteries, and the like) which present a definite menace to the contact troops, are never seen except from the air. The primary mission of Field Artillery is to concentrate its fire on these targets, yet in 90% of the cases, torrential observation is non-existent for these types of targets. Therefore, if the Field Artillery is to perform its mission effectively, an elevated observation post which will allow surveillance of defiladed areas within hostile front lines to the limit of observation is absolutely necessary.

The solution is in some form of aircraft… each battalion should have at least one aircraft ready for use or immediately available at all times. One flight of not leas than seven aircraft with pilots and maintenance crews should be an organic part of the equipment and personnel of each artillery brigade headquarters.

It is expected that the operation of the relatively simple and inexpensive type of aircraft which will satisfy the requirements of division artillery… should be able to land and take off from small unprepared lending fields in the vicinity of the artillery command posts or along its route of march. Low cruising speed to permit of continued spotting of artillery fire is desirable but the primary consideration is low landing and takeoff speeds. For the past two years, the Field Artillery has insisted upon this characteristic in setting up military characteristics for the courier type airplane, short range liaison (light) now represented by the O-49, O-50, and O-51 airplanes. None of these airplanes have been tested to date by the Field Artillery.


Letter to Chief of the Field Artillery, February 7, 1941, from L.S. Ostrander, Adjutant General, by order of the Secretary of War, Henry L. Stimson

Your proposal of an organic observation component in the Field Artillery is not favorably considered at this time.

The established policy of maintaining specialized arms and the organization of units thereof into combat teams is the most economical one in personnel, material and operating facilities. Unless it can be shown conclusively that the present organization of observation aviation, which contemplates the use of some airplanes especially designed for artillery and infantry missions and ground arms personnel as observers, can not be made to meet satisfactorily the needs of the Field Artillery and other components of the ground forces the existing policy will be adhered to.

The employment of the new liaison airplane, type O-49, should be thoroughly tested and determination made as to its suitability and the numbers required per observation squadron. If it is found that the three airplanes of this type initially allotted to each observation squadron are insufficient to meet requirements, the number may be increased as necessary.


Report of Air-Ground Procedure Board on Observation Planes for Field Artillery Use, May 14, 1941, by Edward T. Williams, Major, FA, by command of Brig. Gen. George R. Allin

Recent instructions from the Chief of Field Artillery require that tests be made at Fort Sill of the following aircraft to determine their suitability for observation for field artillery: O-49 Stinson, YO-50 Bellanca, YO-54 Ryan, YO-54 Stinson, YO-55 Ercoupe.

The Stinson O-49 is the most promising of the slow-flying planes covered in this report. Because of its size, it may be difficult to conceal when on the ground, unless camouflaged properly or give a drab color. This airplane can climb rapidly; it can descend more rapidly. Recently in a test take-off the airplane stalled when 50 feet above the ground and fell or glided to the ground without injuring the pilot or observer.

Recommendations [following test, YO-50 not present]: The YO-54 and YO-55 airplanes be not retained for use by field artillery. The O-49 airplane be made available in sufficient quantities to permit a service-wide test.

Annex: The Piper J-3 Cub Trainer was demonstrated here for three days by the Company’s representative. It was not flown by any military personnel. This plane compares favorably with the O-49. With its high wings and tandem seating, it should be satisfactory for field artillery purposes. It is cheap and can be easily serviced. If adopted for the artillery service, its design should be changed to permit upward and rearward vision. A suitable radio must be conveniently installed.

This airplane is sufficiently rugged considering its low speeds for taking off and landing. This permits it to operate on rough terrain. With no wind this airplane can land in 75 yards. It can take off with two passengers in 85 yards, with no wind. Low speed is 30 mph; high speed 90 mph, diving speed about 120 mph. Rate of climb [is] 600 feet per minute up to 2000 feet.

It is recommended that a limited quantity of the Piper J-3 Cub Trainers be procured for service test in comparison with the Stinson O-49, provided a suitable radio is installed.


Final Report of the Air-Ground-Procedure Board, August 19, 1941, by Edward T. Williams, Major, FA, by command of Brig. Gen. Allin

During the school year 1940–1941, the Board made a study of the types of aircraft that could be used for field artillery, For short and medium-range weapons, types considered: the large, slow-flying airplane such as the O-49; the small, commercial-type airplane such as the Piper Cub. (The Ercoupe and the Stinson C-105 [Voyager] sent here for test were unsatisfactory.)

The field artillery must have its own organic observation airplanes. One squadron for the division artillery and for each artillery brigade is recommended. The field artillery cannot rely on air-corps observation planes assigned to division and corps; these planes will be taken for other missions.

For the majority of field artillery fire missions, a light, commercial-type airplane is satisfactory. These are the personal opinions of two members of the Staff and Faculty. The large, slow-flying airplane has the advantages of sturdiness, the ability to stand rough treatment in taking off and landing in restricted areas, and the ability to carry additional weight including personnel and some type of gun for protection. As long as this plane remains in the air unmolested it is an excellent OP.

The light commercial-type airplane has the following advantages:

  • It is small, cheap, and light, and could be made available in quantity.
  • It can be easily concealed, the wings being removed, if necessary.
  • Its maintenance is simple.
  • There are a large number of light-airplane pilots in this country; they would not necessarily need the detailed Instruction given to pilots of the air corps.
  • If issued in quantity these airplanes would be immediately available to artillery battalions.
  • When flying at comparatively low altitudes over our position area, the small airplane would be difficult for pursuit planes to discover.

The field-artillery airplane should have the following characteristics:

  • Unobstructed vision for pilot and observer.
  • Tandem seating, with the observer being able to face to the rear.
  • Ability to take off and land in restricted areas.
  • Simplicity and ruggedness of construction such as will make maintenance under adverse field conditions practicable.
  • Small size, to permit concealment and loading on trucks for transport.
  • Ability to carry a two-way radio set.
  • Sufficient maneuverability in flight for evasion of an attacking.

The commercial-type airplane more nearly conforms to the above characteristics than does the large slow-flying type.

A squadron of light commercial-type airplanes be an organic part of the division artillery and artillery brigades. A squadron of light commercial-type airplanes be sent to Fort Sill for test and instruction purposes.


A Treatise on the Fast Airplane versus the Slow-Flying Light Airplane for Observation of Artillery Fire, July 31, 1941, by Dudley B. Howard, Colonel, Air Corps

The airplane for artillery fire missions must be able to operate out of very small clear areas, roads, etc., such as usually will be found, or may be prepared easily, in country in which field artillery can operate. Therefore, the Field Artillery and the Air Corps have been experimenting with slow-flying, light airplanes for several months in an endeavor to find one which will meet the requirement mentioned.

The airplanes tested of the specially designed, fixed-wing type, which were equipped with slots and flaps to reduce the landing and take-off speed, averaged about 390 feet for both landing and take off, over a 50 foot obstacle and with no wind. In this class, the most generally satisfactory airplane was the Stinson O-49. Although not officially tested, a Piper Cub airplane was demonstrated by a company pilot. This airplane took off and landed on a concrete surface in a run of exactly 80 feet, measured by the writer. There was a surface wind of slightly more than 20 miles per hour at the time. The pilot stated that the same airplane had taken off and landed at Fort Knox, Kentucky, with zero wind in a run of 222 feet. From the foregoing, it will be apparent that there is an airplane available which should be able to operate from landing areas which should be found, or can be prepared, in the immediate vicinity of all artillery positions in a combat zone.

Airplanes of the specially-designed fixed-wing type, such as the Stinson O-49, are complicated in construction, large in size, and are too heavy and unwieldy for ease of man-handling on the ground and truck transportation. The Stinson O-49 has a feature which deserves special mention, however. Its shock-absorbing landing gear is so sturdy and efficient that it can stand hard landings on rough ground.

Of all the aircraft which have been tested or demonstrated here, only one met all requirements, the Piper Cub.

Apparently, an airplane of the Piper Cub class is entirely suitable for use in observation of artillery fire under the most trying conditions which can be anticipated.


Memorandum to the Chief of Staff, War Department, October 8, 1941, by R.M. Danford, Maj. Gen., U.S. Army, Chief of Field Artillery

The present organization of observation aviation does not meet the needs of the Field Artillery. It does not provide an adequate number of observation airplanes, timely observation, and that cooperation so essential between the observer, pilot, and firing unit commander. This paper [including the above reports and findings] discusses the problem and proposes the only apparent, practical solution.

The O-49 Is the standard observation-liaison plane. It is relatively expensive. There are less than 50 available. Procurement plans contemplate about 300 by 1942. This number scarcely meets half of the Field Artillery’s requirements for observation planes since it needs today one such plane per battery for effective observation of fire. Tests have shown… the light, relatively inexpensive, commercial airplane of the Piper Cub type to be a usable substitute.

There are two types of air observation missions required by Field Artillery. The first is the observation of long-range, heavy artillery fires deep in enemy territory. These missions should be performed by well armed and armored observation airplanes generally protected by pursuit aviation. The second type of mission, that of observing the fires of light and medium artillery, will constitute the bulk of Field Artillery air-observation requirements. These missions normally will be designated by artillery commanders and should be performed by slow-flying, liaison type, observation airplanes, operating as “elevated observation posts” directly above our own artillery areas at comparatively low altitudes. They should land on and take off from terrain close to artillery position areas.

Commanders in the field have convinced the Chief of Field Artillery of the soundness of the following… that not less than seven airplanes with pilots and maintenance crews be authorized as an organic part of each artillery component of each infantry, motorized, armored, and cavalry division, and of each corps artillery brigade.

That the Chief of Field Artillery, in collaboration with the Chief of Air Corps and the General Staff, be authorized to proceed at once with detailed plans to implement the organization, training of personnel and procurement of suitable materiel.

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