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 From Spring '97 Bronco Flyer 

Broncos in Venezuela
OV 10 Propellers
Not All Broncos Are Created Equal

Broncos in Venezuela

The history of the OV-10 Bronco in Venezuela begins at the height of the Vietnam War Extensive operations by the U.S. Marine Corps. Navy and Air Force in Vietnam proved the toughness and eftectiveness of the aircraft in Forward Air Controller (FAC), observation and light attack roles. Venezuela decided to acquire similar aircraft for their counterinsurgency missions and ordered 16 aircraft in December, 1971 The Venezuelan model was designated the OV-10E Bronco.

Delivery of the OV-10E to Fuerza Aerea Venezolana (FAV) Bombing Group 13, Squadron B-40, started in March 1973. The final four aircraft left the Columbus Aircraft Division of North American Rockwell in July of the same year. (Picture below.) After a period with Squadron B-40, the Broncos were transferred to the 15th Special Operations Group in Maracaibo where they remain today. The primary mission of the aircraft now is a cooperative venture with the National Guard to patrol the border and control smuggling. The light armament. excellent visibility and responsive maneuverability of the OV-10 make it an ideal aircraft for this role.

In 1991, FAV acquired 18 former U.S.A.F. OV-1OA Broncos to join their remaining OV-10E Broncos operating out of Maracaibo. They are so pleased with the OV-10 capability they want to use them for the next 20 years.

To meet this goal, Venezuela is planning a Service Life Extension Program (SLEP) to provide an additional 5,000 hours service life on the aircraft. An inspection of the OV-10 fleet in Maracaibo determined the actual structural condition of the aircraft and concluded replacement parts are necessary to extend the service life. Installation of a basic kit and implementation of an inspection procedure based on the U.S.M.C. OV-10D SLEP is under consideration by the FAV. Additional changes to the aircraft are being considered to bring the "A" and "E" models into a common avionics configuration..

Completion of the Service Life Extension Plan will insure the Fuerza Aerea Venezolana of operational aircraft for many years to come following the example set by other North American products such as the T-6 and the B-25.

OV-10 Propellers

Alternate propellers for the OV-10 is a frequent subject of discussion among Bronco users. The most common complaint, going back as far as Vietnam War days. is the noise and vibration. Both create problems for pilots on long missions. Noise propagation also causes a detection problem for military users who usually do not like to advertise their location.

Only two propellers have ever been qualified for normal use on the OV-10 Both are counter rotating propellers. rotating inboard down. The OV-1OA B. C, E, and F all use the 33LF-337 and 33LF-338; the OV-10D (a modified OV-10A) uses 33LF-335 and 33LF-356.

The basic characteristics of these propellers are shown in the table below.

NASA has at times used other propellers during various test programs but none of these installations were qualified for fleet-wide use. In 1986, Rockwell International completed a contracted study of alternate propellers for noise reduction on the OV-1OD They concluded a reduction of 13-17 dB in the cabin and 6-8 dB far-field is possible using a combination of the following:

•   Decrease blade diameter,
•   Increase blades to 4 or 5,
•   Load shaping of blade,
•   Synchrophasing,
•   Reversing the rotation.
  

Rockwell also concluded the use of a redesigned 4 or 5 bladed propeller could achieve a reduction of at least 6 dB without compromising aircraft performance. There is also some indication that an odd number of blades is preferable due to possible wing-propeller beat interaction. It was estimated that this modification would require about two years to develop and implement.

Not All Broncos Are Created Equal

The OV-10A Bronco is a rugged, maneuverable, twin turboprop multipurpose aircraft loved by pilots These same pilots, of course, always complain about needing more power. Once upon a time, someone decided to do something about it.

In 1972. the civilian firm of Rhein-Flugzeugbau (of what was then West Germany), contracted with North American Rockwell's Columbus Aircraft Division to add a jet to their version of the Bronco. The German Bronco. designated the OV-lOB, was used by Rhein-Flugzeugbau to tow targets for the military. The modified aircraft [the OV-lOB(Z)] mounted a GE J-85 turbine in a pod on the upper surface of the center wing section. This was designed to provide the additional power needed for some of the tow missions.

Six of the modification kits were produced. One was installed by the Columbus Aircraft Division for the prototype. One was installed by Rhein-Flugzeugbau in Germany. The other four kits were never installed. The remaining aircraft have been removed from service.