Aerofax Minigraph 11 - Grumman-Schweizer AG-CAT

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Aerofax Minigraph 11



by Nick Pocock

General Equipment Locations

1. Battery 2. Fuel FilierCap 3. Oil Fuel Cap 4. Master Cylinder and Reservoir 5. Hopper Door 6. Navigational Lights 7. PitotTube 8. Stall Warning Sensor 9. Trim Tab 10. Foot Holes 11 . Baggage Compartment Door 12. Air Filter Access Door 13. External Power Supply 14. Fuel Gauge

© 1994 by Nick Pocock; Library of Congress #94-69850; ISBN 0-942548-59-0 Published by: Aerofax, Inc and Special Aviation Publications P.O.Box120127 Rt.1,Box730 Arlington, Texas 76011 China Spring, Texas 76633 817261-9145 817641-4269 fax.: 817 459-0726 European Trade Distribution by Midland Publishing Ltd., 24 The Hollow, Earl Shilton, Leicester, LE9 7NA, England; 0455 847256/fax.: 0455841805


The prototype G-164 Ag-Cat, N74054, constructornumber X-1, atSchweizer's Elmira, New York facility. Noteworthy is the spraypump fairing visible below the firewall between the spring steel struts of the main landing gear.

PROGRAM HISTORY: The ancestry of the Ag-Cat includes that series of muscular warplanes produced by the Grumman Iron Works, so named for their extraordinarily rugged airframes. It first flew in 1957, following in the paw-prints· of the Wildcat, Hellcat, Bearcat and Tigercat fighters of World War Two. Though the fighters had been monoplanes, the Ag-Cat returned to the biplane tradition of the pre-war Grummans. This layout had the rugged

strength and other desirable qualities required for its work as an ag-plane...which is an aircraft used in agriculture to dust, spray, or seed crops. Joseph Lippert was responsible for the origin of the Ag-Cat program. In 1955, as aerodynamicist of the preliminary design group at Grumman Aircraft Corporation, he discussed with Arthur R. Koch (pronounced "Coke") the possibility of designing an agricultural airplane, and that as a team, they

should endeavor to sell the idea to Grumman with the emphasis on forming a Grumman non-military company. The latter which would build a prototype of this aircraft and Ultimately, manufacture it to sell to the agricultural industry. Joe Lippert studied the eXisting information about "dusters" (as they were called in those days). He then made a trip with Arthur Koch through the southwestern United States to observe ag flying operations


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The far-sighted LeRoy Randle Grumman was born in 1895 and died in 1982.

Joe Lippert and the original Ag-Cat model he built to sell his idea to LeRoy Grumman.

ArthurKoch listened to Joe Lippert's suggestion that the Ag-Cat be built.

Grumman's X-1 prototype, N74054, seen before engine relocation andprobably before the aircraft's first flight. Grumman facility is visible in background.

Grumman's X-2 prototype, N74055, shortly before completion and first flight. Fuselage panels and cowling parts have been removed for photography.

Three-quarter rear view ofGrumman's X-2 prototype with the majority ofits fuselage access panels removed. Structure was simple but rugged.

Grumman 's X-2 prototype in flight. Aircraft's docile flight characteristics became readily apprent early in the flight test program.


and talk to people in the business. From this research he then determined the original specification, and made the initial sketches. At that time most of the aircraft used for agricultural work were modified Stearman Kaydetbiplanes--which were World War Two trainers--and other modified types, many of which were not entirely suitable for the job. The Stearman, although the most numerous and best-suited, had some deficiencies which would need to be eliminated in a new design: the landing gear needed to be less demanding from a maintenance standpoint while remaining rugged; the aircraft needed to be inherently quick at stall recovery with instant aileron response while maintaining light control forces to reduce pilot fatigue; it had to be capable of carrying approximately twice the hopper loads of the best Stearman conversions fitted with the 220 horsepower Continental radial engine. Koch, who had been a designer for Grumman since 1935, designed an aircraft based on Lippert's specifications and sketches, with Lippert assisting with the aerodynamic layout, powerplant selection and installation, and the spraying and dusting systems. This resulted in the proposal forthe Grumman G-164, which later would become known to the world as theAg-Cat. Lippert chose the biplane configuration to minimize the wing span required to carry the specified load, with the advantages of a smaller turning-radius for more economical turn-arounds at the end of a swath run. The biplane's improved maneuverability, with its higher rate of roll, also would help to reduce the time spent in turns, and improve safety during turns. (An ag-pilot knows that he is not making any money during the turn-around!) A biplane arrangement also provides a strong, light structure, with good crash-protection for the pilot. In order to reduce the chance of a crash due to stalling, the top wing of the G-164 was designed to stall first. By arranging the stagger and gap between the wings so that the upper wing acts as a slat, a slot-effect is created that improves the airflow over the lower wing. Thus, with the unstalled lower wing still providing lift and with its center of pressure further aft, there would be a moderate nosedown pitching moment which would tend to unstall the top wing. The pilot thus would not

Humorous proposal to the AirForce calling for a military version of the G164 as an "anti-insect weapon system".

Grumman's X-2 prototype during initial tests of liquid spraying system and associated capabilities.

have to take corrective action with the elevator controls. The ailerons thus remain powerfully effective even during the stall. Since stalling is one of the most frequent causes of agricultural airplane accidents, this safety feature was well justified, and undoubtedly contributed to the excellent safety record of the Ag-Cat. Koch and Lippert had misgivings about trying to sell the idea of this agricultural aircraft to the chief engineer of what was, basically, a military establishment. They, therefore, approached Leroy Randle Grumman directly. Mr. Grumman, as he was usually called--founder of Grumman Aircraft Corporation--had not been active in the daily operation of the company since the end of the World War Two, but he still loved airplane design, and worked with his small group of talented engineers on preliminary designs and product development, until his retirement in 1966, at the age of 71. He was only mildly interested in the ag-plane proposal at first. After about a month-and-a-half of discussions, however, and some encouragement from Leon A. "Jake" Swirbul, Executive Vice President, Mr. Grumman finally accepted the proposal to design and build two identical prototypes. These were to be built in a commercial plant outside the higher-cost military environment, and under the supervision and control of Koch and Lippert. The design and construction of the two Ag-Cats would be funded to a limit of $200,000. Koch and Lippert had just started on the project when Mr. Grumman was persuaded by the head of the experimental shop to produce these prototypes under his supervision, in one of the hangars at Grumman's military facility, with subsequently higher overhead and labor costs. Furthermore, he suggested that while the two prototypes (to be designated X-1 and X-2, respectively) would be identical in external configuration, they would be built with two different internal structural configurations for the wings, with X-2 having a geodetic rib arrangement. This slowed the completion of the project and increased the cost to $600,000. The design and fabrication of the G-164 prototypes was completed after several months. The first flight of X-1 (N74054) took place on May 27, 1957 , flown by test pilot, Franklin T. "Hank" Kurt, who had been appointed to the job by Mr. Grumman. The G-164 lived up to its designers expectations,

Grumman's X-2 prototype found its way to the Texas State Technical Institute in Waco, Texas where it was later restored.

Bill Schweizer was a strongproponent of his company's Ag-Cat production program.

Paul Schweizermade the family name a major playerin sailplane production.

and a type certificate was issued on June 21, 1957. (Both prototypes are extant as of 1994: X-1 is on display at the National Agricultural Aviation Museum, in Jackson, Mississippi; and X-2 is used as an instructional aircraft at Texas State Technical College, in Waco, Texas.) Terrell Kirk remembers that the Ag-Cat was a very easy aircraft to fly, especially the

original G-164, which was fantastically maneuverable. Its rate of roll, and roll acceleration, were greater than any World War Two fighter--it was a very responsive airplane. Koch and Lippert then went on a demonstration tour throughout the southern states to determine the acceptance of the G164 by the agricultural industry. More than

The G-164 's structure is conventional but is optimized for extraordinary strength and durability. Particular emphasis has been placed on the cockpit andassociated roll-over assembly.


From left to right: Bill Schweizer, Paul Schweizer, Schweizer test pilot Clyde Cook, and Ernie Schweizer on the occasion of the first production Ag-Cat's successful first flight.

Testflying the first production G-164, N10200. This was the first Ag-Cat to be manufactured by Schweizer at their Elmira, New York facility.

three hundred ag-pilots flew the prototypes, directly comparing them with the aircraft they were then using on cotton or rice crops. Their response was very encouraging. Koch and

Lippert returned to the factory at Bethpage, New York, and after reviewing the results of the demonstration tour, it was decided by Mr. Grumman to produce the aircraft, and to

Schweizer Aircraft Corporation's factory at Elmira, New York during 1974. Numerous production AgCats are visible to the right.


locate a new facility in which to produce the G-164, as originally planned. In the spring of 1957, while the prototypes were being built, Fred Eckert, assistant to George Titterton,Vice President, Contracts, in charge of manufacturing operations at Grumman, had invited Bill Schweizer, one of the founders of Schweizer Aircraft Corporation (SAC), manufacturers of metal sailplanes (see "History of SAC' later in this book), to see him during his next visit to Grumman on subcontract business. Eckert showed him the aircraft, and asked whether Schweizer could build them. Bill assured him that they could. Brothers, Paul and Ernie Schweizer, also visited Grumman to look at the G-164, and they all agreed that it would be an ideal project for their company. Eckert suggested that Schweizer prepare a budgetary quotation for planning purposes. The proposed program included bUilding the production tooling, and manufacturing the first one-hundred aircraft. In June, 1957, Bill Schweizer took Paul Pullen, Ernest Whidden, and John Griswold, three of his top manufacturing people, to Grumman for two days to study the working drawings and the prototype aircraft. After several weeks of searching for a suitable available facility, George Tittertan, on a visit to the Elmira, New York, facility of Schweizer Aircraft Corporation (already a sub-contractor of Grumman's), decided that the G-164 would fare best by being produced for Grumman under sub-contract. During September, 1957, a contract was negotiated for the production of one-hundred aircraft, to be approved by the SAC board, and Grumman management at the end of the month. As Bill Schweizer had been following up on the project, he went to Grumman during the first week of October, 1957, to sign the contract. By January, 1958, the production program was well under way. SAC personnel were excited. They felt that ag-plane manufacturing would be a stable business, rather like making farm tractors! The G-164 aircraft still did not have a name. Mr. Grumman wanted to call it the "Grasshopper", but the marketing people were not enthusiastic about this name for advertising and sales. At a distributors meeting Dick Reade, of Mid-continent Aircraft Corporation, asked: "Why not follow on from the Grumman series of fighters: the Wildcat, Hellcat, Tigercat, and Bearcat? How about, 'Agricultural Cat', or 'Ag-Cat'?" And the AgCat itbecame. The arrangement was that Grumman Aircraft Engineering Corporation owned and managed the program, and controlled the design. SchweizerAircraft Corporation manufactured, flight tested and obtained FAA (Federal Aviation Administration) certification for each aircraft, before it was presented to Grumman, who then paid Schweizerfor it. Grumman then handled the marketing and sales. Koch stayed with the Ag-Catprogram at Elmira as Chief Designer, handling production design changes and improvements until his retirement in 1972, although continuing to do consulting work for Schweizer Aircraft Corporation up through 1987. Lippert continued with Grumman and the Ag-Catprogram until 1962, after which he was involved only as a consultant, as the aircraft was modified. Schweizer estimated that it would take

fifteen thousand man-hours to build the production tooling for the complete Ag-Cat which, with ten men, would normally be ninemonths. They set a goal to complete the tooling, and to run five sets of parts by July, 1958. In August they started assembly of the first production aircraft, using the more conventional parallel wing-rib arrangement as on the prototype X-1. On 17 October, SACtest pilot, Clyde Cook flew it for the first time. Grumman representatives About ten attended Schweizer's first Ag-Catflight ceremony, including Terrell Kirk, designated Ag-Catsales manager and acceptance pilot. Four Ag-Cats were delivered to Grumman by the end of the year 1958. The G-164 was certified by the FAA in the Restricted Category in January, 1959, with the 220 hp Continental W670-6N sevencylinder radial engine. (Other engines available, FAA certificated by Lippert during the period 1959 to 1962, were: 240 hp Gulf CoastW670-240, a tank engine modified by Bill Lewis; and 245, 275 and 300 hp Jacobs.) The contract production schedule required one aircraft per week by March, 1959, and two per week by October, 1959. By the end of March twelve FAA certified AgCats had been delivered to Grumman. The two prototype aircraft had been equipped with landing flaps on upper and lower wings, but since it was found that shorttake off and landing performance, necessary for agricultural work, was satisfactory without using flaps, it was decided not to incur the additional expense and complication of including them on the production G-164 aircraft. The contract specified that the agricultural material hopper should be installed in the aircraft, but it did not include the spray and dust dispersal systems, considered accessory equipment, which Grumman felt could be installed later. When they started the development of the installation of the systems, they found that (by Murphy's Law) the job was more complicated than expected. Ag-Cats ordered by customers, were ready for delivery - without dispersal systems. Grumman and Although both Schweizer had a lot of experience in engineering and building aircraft, developing agricultural systems was something new for them. They worked together, however, to solve the basic problems of providing an even distribution of spray or dust over the application area, and controlling the volumeper-acre applied, while protecting the pilot from harmful effects of the agricultural chemicals. Grumman obtained the advice and assistance of some experienced aerial appli-

The first production G-164, N1 0202, constructornumber 1,seen during operational use, was manufactured during January of 1959 and licensed the following month.

cators. Joe Lippert went down to Texas A&M University with an Ag-Cat to work with Joe Brusse for several months on the field development and testing of a spray and dust distribution system. When they thought they had perfected an acceptable spray system, they found thatthe environmental regulations in some states required a "suck-back system" for the spray booms to positively stop the flow of chemicals when the pilot shut off the system, thus reducing the chance of chemicals being dropped outside the intended application area. Bill Schweizer recalled that when the first dust spreader was ready for flight testing, they could not get any inert foundry talcum powder, as normally used for testing. Grumman's service test pilot, Terrrell Kirk, suggested using lime, and took off with fivehundred pounds of it in the Ag-Cat's hopper. When he opened the dust gate in flight, the dust came out of the spreader, but some was sucked back into the tail section of the fuselage and into the cockpit. Kirk almost suffocated, and emerged from the cockpit a giant white snowman. Realizing that the open cockpit was a low-pressure area, they solved the problem by installing a dust-seal bulkhead behind the cockpit, and inducing air into the cockpit to raise the pressure. By the end of April, 1959, Grumman and SChweizer were satisfied that the dispersal systems were debugged and ready to market, and Grumman started delivering the Ag-Cats to the customers. Unfortunately the operators were unhappy with the spray and

dust systems on the new aircraft, even though they were the latest then in existance. Grumman sent out technical representatives to investigate the complaints, some of which were legitimate, but many were not. Each operator seemed to have a different idea of what was wrong with the system, and how it should be redesigned, and seemed to be prejudiced against any system different from their own ideas. The Ag-Catwas one of the first special-purpose agricultural aircraft in the world to be manufactured and sold with a factory-installed dust-and-spray system. Prior to this most ag operators bought surplus military biplane trainers for less than a thousand dollars, which was about five-percent of their original cost. They usually bought two aircraft, one modified as a duster, and the other a sprayer, by using equipment such as hoppers, fans, valves, pumps, and spray nozzles, purchased from ag suppliers, to install their own systems. There was a tendency for operators to be proud of their own systems and designs, and perhaps to overlook any of their shortcomings. These systems would probably have failed to comply with the state regUlations, whereas the Ag-Cat system had been tested to do so. Joe Lippert soon found that the real problem was: each section of the country had different requirements depending on the crop. For example: Louisiana, rice; Mississippi, cotton; Texas, range; California, garden vegetables; etc. Since the military-surplus trainers could be purchased and modified so cheaply, it was

The second aircraft from the right, N63W, seen in a batch ofinitial production Ag-Cats, was the third production G-164. It was sold to Lyon Flying Serice, Inc., in Louisiana. Near-leading-edge placement ofspray bars is noteworthy.


The eleventh production G-164, N1 0211 on August 11, 1975. Atthe time, it was being operated by MOE. Ag-Cat logo on roll-over headrest is noteworthy.

The twelfth production G-164, N10212, with a 600 horsepower Pratt & Whitney radial. At the time, March 28, 1969, the aircraft was operated byBronner & Jones Flying Service.

N10271 was the seventy-first G-164. Above-trailing-edge location of spray bars is noteworthy. Visible to right is G-164, N676Y.

difficult for operators to justify the fifteen thousand dollar cost of a new Ag-Cat, even though one aircraft could be used for dusting, or spraying, and the type had passed stringent testing. Due to the slow acceptance of the AgCat by the operators, Grumman slowed down the production at Schweizerto one aircraft per month until sales improved. By the end of 1959, a total of 35 Ag-Cats had been manufactured, but only 10 had been delivered to customers. During 1960 production was set at two aircraft per month. With suggestions from the field, and the help of Ernie Schweizer, who was an FAA approved DER (Designated


Engineering Representative), the Ag-Cat was debugged and design improvements were made, and approved qUickly on site at Elmira. The first foreign deliveries were made to Panama and Uraguay in July, 1960. Sales almost tripled with 29 Ag-Cats being sold in 1960. A total of 64 had been built, leaving 25 in inventory. Having open cockpits, these aircraft created a storage problem, as Grumman decided that they should be hangared during the winter. Since there was no spare hangar space at Elmira, the aircraft were flown to Hornell and Ithaca airports. Bill Schweizer has some happy memories of helping Terrell Kirk with the ferry flights. It seems the flights of two were not

always along a straight course, with Bill trying to shake Terrell off his tail! In 1961 production was increased to three per day, 34 being manufactured. By the late spring 1961 sales started to pick up and 56 Ag-Cats were sold that year. Thus the inventory was reduced to three aircraft, and a backlog of 30 orders for aircraft to be delivered in 1962. Finally the companies efforts were begining to payoff. In the summer of 1961 Schweizer negotiated an order for a second hundred Grumman Ag-Cats (SIN 101-200). To help stimulate sales, Terrell Kirk, AgCat sales manager, was working with Grumman's advertising agency on a new advertisement. They wanted a picture of an Ag-Catspraying corn. Kirk picked out a lush cornfield between old Route 17 and the Erie Railroadtracks in Big Flats, near the airport at Elmira. The photographer took his position in the narrow field, and Kirk started a spray run with the wheels just above the top of the corn. Unknown to Kirk, there was an electric wire across the center of the field that he had not seen because it did not have any supporting poles in the field. The Ag-Cathitthe wire, was pulled down into the corn, and then bounced up again. Kirk flew the "modified" swept-wing Ag-Cat back home, trailing streamers of corn leaves. Seventy-seven Ag-Cats were delivered in 1962, and the 190th was built since production had started in 1958. Grumman ordered another one-hundred aircraft, serial numbers 201-300, in September, 1962. Seventy-two were sold in 1963, giving a total of 244 in service. Supplying Ag-Cat spare parts had now become seven-percent of Schweizer's total business. There were also some foreign orders awaiting payment at the end of 1963, as all deliveries from Schweizer are on a cash-ondelivery basis. A Japanese company had ordered an Ag-Catin January, 1963, and had made a downpayment. The aircraft was disassembled and crated, but by December it was still in the shipping area. Bill Schweizer remembers that someone had asked Clyde Cook, final assembly inspector and test pilot, what was holding up the shipment? Cook answered, "Apparently the Japanese have no 'yen' forthe Ag-Cat." In the fall of 1963, ten Ag-Cats were delivered to a big ag-plane operation in the cotton plantation area of Guatamala. AgCats delivered across the Atlantic or Pacific oceans are normally crated, or containerized, but those going to Central or South America are flown by professional ferry pilots, or by the customers' pilots. To increase the aircraft's range, extra fuel was carried in the chemical hopper, and a hand-operated wobble-pump was used to transfer fuel from the hopper to the main fuel tank in the center-section of the top Wing. Each pilot was given a brown paper bag containing about five hundred one-dollar bills to pay for fuel and travelling expenses. Piper's new 235 hp Pawnee with 150 gallon hopper--smaller and lower priced-was proving to be a competitor to the Ag-Cat. Grumman management decided that the AgCat could be made to carry a bigger load with some minor changes, which would make it more economically efficient. Starting with a new contract (SIN 301400) the 220 hp Continental engine was replaced by a 300 hp Jacobs R755 engine, which allowed the hopper size to be

increased from 215 to 245 gallons. The new hopper was made of aluminum, and welded to provide better sealing. The most impressive sales feature was that the Ag-Cat could now carry one ton of water-soluble agricultural material. These features, and some other service impovements, were tooled for production, and FAA certification during the fall of 1963, and the new model was ready for the spring 1964 market. A total of 400 opencockpit G-164 Ag-Cats were built. Engines ranged from the original 220 hp W670 Continental; the Gulf Coast 240 hp; the 300 hp R755 Jacobs; and 275 and 245 hp Jacobs. Beginning with serial number 401 the Super Ag-Cat G-164A, powered by a 450 hp R985 Pratt & Whitney, with a 300 gallon fiberglass hopper, and an optional closed canopy, was certified in March, 1966. It was also available with the 300 hp Jacobs, and later, in 1969, the 600 hp R1340 Pratt & Whitney. A total of 1,730 G-164's, and G-164A's were eventually built. By 1968 an enviable safety record had been established for an ag-plane, as over one million hours had been flown by Ag-Cats in the U.S.A. without a fatality. There are a number of design features which have contributed to this achievement: good overturn protection from the tubular structure behind the pilot's seat (designed for this purpose); the upper wing; and high fin and rudder; slow take-off and landing speeds; all structures around the pilot's cockpit stressed to 40G; two sets of wings and a long nose capable of absorbing a lot of crash energy; fuel tank in the center-section isolating fuel from cockpit area; and biplane configuration with forwardstagger prOViding stability and gentle stall characteristics. The first fatal accident occurred on 25 March 1968, when serial number 20, N10220 crashed near Lancaster, California killing the pilot who had flown a total of twenty-five hours in the type. In 1971 the Ag-Cat's fuel capacity was increased from 46, to 80 gallons by adding two optional tanks in the upper wing panels. Also, a new urethane-resin paint finish was used to inhibit oxidation of all metal parts. In October, 1972 the 1,00ath Ag-Catwas built. Grumman's new commercial airplane division, Grumman American Aviation Corporation (GAAC), had direct sales responsibility for the Ag-Catprogram in 1973, when their contract with SAC was for 150 aircraft. Although 171 were actually built, this still did not satisfy the sales demand. To justify a SAC plant expansion, an agreement was made by GAAC to buy 200 Ag-Cats in 1974,245 in 1975, and 300 in 1976. In 1974 three new models were planned by Grumman American to meet the expanding ag-plane market: G-164A-The current production model with a new sealed cockpit for pilot protection from chemicals, and powered by the 600 hp R1340 Pratt & Whitneyengine. G-164B-With wing span increased from 36 to 42-foot-3-inches, so that it could carry the same load as the "A" model, and provide a wider spray swath, powered by the 450 hp Pratt& Whitneyengine. G-164C-With a new fuselage design for a 500 gallon hopper, 42 foot-3 inch-wing span, and powered by the 600 hp R1340 Pratt& Whitneyengine. In September, 1974, Grumman

American brought two large trailers, and a staff of seven engineers to work with Schweizer on the design and FAA approval of these new models. By December the new "A" Model was in production. By January, 1975, 1,400 Ag-Cats had been built, and were operating in 34 different countries. In Novemberthat year the G-164B Super Ag-Cat B with a 300 gallon hopper, modified vertical tail surfaces, and longer wings and spray-boom, was certificated. It was powered by either a 450, or 600 hp Pratt & Whitney engine. In February 1976 the Super Ag-Cat C was flown, and in November 1977 was certificated; it had a deeper and longer fuselage accomodating a 500 U.S. gallon hopper. This was found to be too big and heavy for the power available from the 600 hp Pratt & Whitney R1340, and only 44 were produced. Production of the Super Ag-Cat A ended in December 1977. Grumman Aircraft Engineering Company, restructured in 1969 became the Grumman Aerospace Corporation, a subsidiary of the Grumman Corporation, had been marketing the Ag-Cat. Subsequently its subsidiary, Grumman American Aviation

Distinctively simple planform of the G-164 is demonstrated by N 10291.

G-164, N496Y, was constructor number 153. It was manufactured during 1962 and was operated by Zumwalt Aviation at the time this photo was taken.

G-164, N579Y, was constructor number 170. It is seen with the majority ofits fuselage access panels removed. Completely enclosed cockpit had become optional by this time.


Onstott Dusters' G-164, N594 Y, constructor number 185, equipped with a Pratt & Whitney R1340. This aircraft laterbecame TG-FIR-F.

Thayer Brothers' G-164, N599Y, constructor number 190 during 1965. It was modified to incorporate a Vultee BT-13's Pratt & Whitney R985 engine, cowl, propeller, and windscreen.

In 1965, Farmers Crop Dusters ofBakersfield, California operated G-164, N657Y, constructornumber 199. It had a 600 horsepowerPratt & Whitney. Later registered as TG-FIL -F.

Company, was bought by Gulfstream American in 1978. All production Ag-Cats continued to be manufacted by Schweizer Aircraft Corporation, at their Elmira, New York, factory. On 30 May 1980, however, the Ag-Cat production was stopped at SAC, as Gulfstream American announced that they would start building the Ag-Cat at their Savannah, Georgia, plant. It took thirty-two tractor-trailer loads to transport the inventory of tools, parts, and materials to Georgia. Production never started in Savannah, how-


ever, and in September, 1980 the Ag-Cat program was offered for sale. By the end of November Schweizer agreed to purchase the program for 3.3 million dollars. By the end of 1980 Schweizer had produced 2,455 Ag-Cats: 400 G-164's, 1,330 G-164A's, 659 G-164B's, 44 G-164C's, and 22 G-164D's, which were Super Ag-Cat C's with a Pratt & Whitney PT6A turbo-prop engine. In January, 1981, Schweizer had bought the Ag-Cat manufacturing and mar-

keting rights from Gulfstream American, and T.C. "Joe" Kosier was hired as Ag-Cat sales manager. In October Schweizer produced their version of the G-164B, known as the AgCat B-Plus, with longer wings and a 400 gallon hopper, and was powered by either a 450 hp R-985, or a 600 hp R-1340 Pratt & Whitneynine-cylinder radial engine. The improvements in load-carrying capabilities as the Ag-Cat evolved were not without some penalties. As weight and power were increased, control forces and feel became heavier, and response was slower. As more Ag-Cats were produced there were eventually more fatalities while flying them. For example, there were four during the years 1983-84. Since 2,567 Ag-Cats had been manufactured through May 31, 1985, of which about 1,700 were still flying in the U.S. an average of 400 hours a year each, the estimated fatality rate therefore has been one in every 340,000 hours offlying. By 1989 Ag-Catproduction consisted of about twelve aircraft per year of the G-164B Super BAg-Cat, with a top wing raised eight inches, which had been introduced in 1983 for improved visibility, and aerodynamic efficiency. These were powered by 450, or 600 hp Pratt & Whitney radial engines, some components of which were in very short supIn ply and therefore more expensive. addition, through a manufacturing agreement with Ethiopian Airlines, nine kits were shipped to Ethiopia for the manufacture of G164-BT Ag-Cats, powered by PT6-34AG Pratt & Whitney turbines. These aircraft are known in Ethiopia by the name Eshet, meaning fresh (crops). To our knowledge the Ag-Cat has been in continuous production longer than any other agriCUltural aircraft, 1957-1994. The proof of the pudding, they say, is in the eating; the Ag-Cat has been helping to feed people for over thirty years. AG-CAT MODIFICATIONS: Agri-Jet Power, Inc.: Don Nance, Route 1, Box 169, McCrory, Arkansas 72101. S.T.C. for installation of GarrettTPE331 Series turbine engines of 575 shaft horsepower on a "B" Model Ag-Cat, making it more streamlined and 600 pounds lighter than with the R-1340. ClarkAviation, Inc.: Joel P. Clark, P.O. Box 327, Bay Minette, AL 36507. Installed 400 h.p. Lycoming on Ag-Cat registered N590Y. EAL Ethiopian Airlines S.C.: P.O. Box 1755, Addis Ababa. Eshet Ag-Cat Super B Turbine kits from SAC assembled under license. 750 shaft horsepower Pratt & Whitney PT6A-34AG turboprop. Six completed by early 1989, the first on 20 December 1986 registered ET-AIY. Frakes Aviation, Inc.: Route 3, PO Box 229-B, Cleburne, TX 76031. Installation of 750 shaft horsepower Pratt& Whitney PT6A34, and in spring of 1978, the PT6A-34AG (derated to 540 shaft horsepower) turboprop. Malden Ag-Craft. Two-seat trainer conversion, exhibited at the Paris Air Show in 1979. Marsh Aviation Co.: William G. Walker, Jr., Vice President, 5060 E. Falcon Drive, Mesa, AZ 85205. Installation of Garrett TPE 331-1-101 turboprop engine, derated to 600 shaft horsepower in Ag-Cat G164, A, B, & C. Certificated in 1980, with six

completed by 1981. Mid-Continent Aircraft Corp.: Dick Reade, Drawer L, Hayti, Missouri, 63851. King Cat, Ag-Cat "G" with Wright R1820 engine. Page Industries: In 1978 installed a 600 hp Lycoming LTP-101 turboprop on an Ag-CatB. Serv-Aero: Salinas, California. Installed a 560 horsepower Alvis Leonides radial, and Dowty Rotol propeller on an AgCat. Stage 1/: In 1978 installed a 650 horsepower hemispherical-head Chrysler engine in an Ag-Cat. Turbines, Inc.: Jim Mills, Route 31, Box 23, Terre Haute, IN 47803. Turbo Cat. PT6 In 1980 Twin Cat Corporation: installed two 310 horsepower LycomingTIO540J horizontally-opposed engines in an Ag-Cat.

Showing some wearand tear, G-164, N332Y was constructor number207. Spray barassembly is visible under fuselage.

------------AG-CAT MANUFACTURERS: Schweizer Aircraft Corp.: Joe Kosier, Ag-Cat Sales Manager, P.O.Box 147, Elmira, NY 14902. HISTORY OF SCHWEIZER AIRCRAFT CORPORA nON: The SchweizerAircraft Corporation was incorporated in Elmira, New York, on December 15, 1939. Its story, however, really began at Peekskill, New York, when the three Schweizer brothers, Bill (12), Paul (17), and Ernie (18), built and flew a primary gliderforthe first time on June 19,1930. This was the SG PI-1 , a training glider of very basic design, consisting of a parasol wing, a single seat mounted on a skid, and tail surfaces, all connected by a very simple open framework. The brothers Ernie and Paul later studied aeronautical engineering at the Guggenheim School of Aeronautics, New York University. When Ernie graduated in 1934 he was offered an engineering job at Grumman, but the work was really as a draftsman. Ernie liked to design, but did not like routine drawing, and since the brothers were working on a design project themselves, he declined the offer of eighteen dollars per week. Although this was apparently an entry level job, had Ernie taken it he would probably have eventually become one of Grumman's top designers as the company grew. When Paul graduated a year later only three or four out of the class of fifty-two students got jobs related to aircraft; the remainder were fortunate if they were able to get a job running an elevator, or anything else, during the depression. In 1937 Paul and Ernie went into partnership to form the Schweizer Metal Aircraft Company, while Bill was still in college. They then produced the world's first all-metal sailplane, the SGUI-6, the designation meaning, Schweizer Glider Utifitysingle-seat, number six. The Schweizer brothers feel that what some may consider to be disadvantages really helped them to eventually build a large corporation, and to survive some of the hard times, where others have failed. First, they had been brought up working hard together in their father's family restaurant business (their father had come to the U.S. from Switzerland in 1905). Secondly, they started their business in the depression years without any capital. They had their father's barn to work in and only limited equipment, and learned to either improvise, or do without.

G-164 N705Y, constructornumber 271, operated during 1966 by Agricultural ServiCes ofFirebaugh, California, had a Pratt & Whitney R1340 and ade Havilland "Otter" propeller.

G-164, N728X, constructornumber282 owned byDouglas Bailey Inc. and seen on February 2, 1974 at Marysville, California. From this experience they learned to adjust to every situation. The three brothers have always worked well together, and if ever they disagree over decisions that have to be made then the majority rules. Ernie specialized in engineering, Paul in finance, and Bill in manufacturing. In December, 1939 the company moved to the Elmira Knitting Miff building, in Elmira, New York. Then in March, 1943, it moved to its present location at Chemung County Airport at Elmira. During the Second World

War Schweizer Aircraft Corporation built single-seat, and two-seat gliders and sailplanes for military use. After the war Schweizer continued to develop and produce sailplanes, and motor-gliders, along with a variety of parts under sub-contract to Bell, Boeing, Grumman, Sikorsky, Edo, etc. As the sons of the Schweizer brothers grew up they became involved with the operation of the company: Ernie's son, Les, engineering; Bill's sons, Paul Hardy, finance and marketing, and Stu, production.


With a slow down in demand for agricultural planes affecting the sales of the Ag-Cat, and the growing popularity of the higher performance fiber-glass sailplanes, which hurt the sales of the all-metal Schweizerdesigns, the sons of the Schweizer brothers negotiated the purchase of the rights to manufacture the Hughes helicopters. This is another example of the diversification and flexibility of operations that has kept the family business going for fifty years - and it is still going strong today. AIRCRAFT GENERAL DESCRIPTION:

Working G-164A equipped with a 450 horsepower Pratt & Whitney radial. Spray bar has been mounted in standard wing-trailing-edge position.

G-164A, N895X, serial number 40 1, prior to delivery. Most of the aircraft's fuselage access panels have been removed to permit inspection.

Classic image ofN903X, serial number 424, following spray run.


The Ag-Cat is specifically designed for agricultural use. It is a biplane with nonretractable landing gear. Power is supplied by an air cooled radial engine equipped with a variable-pitch constant-speed propeller. Fuel is supplied from a main fuel tank in the upper-wing center-section. Supplemental fuel is suppled from outer wing panel tanks for increased range. The pilot's cocokpit is fitted with a plexiglass canopy, overturn structure, and ventilation system. The chemical hopper is located to the rear of the main firewall and in front of the pilot for either dispersal of liquids or solids. Airframe and Landing Gear: The fuselage contains the hopper, sealed cockpit, baggage compartment, and rear section. It is of all metal tubular construction covered by aluminum with a firewall covering the front end to isolate the engine from the fuselage, and a dust- sealing bulkhead aft of the fuselage baggage compartment. Forward, center, and rear side panels are attached to each side of the fuselage utilizing turnlock fittings ("camlocs") for easy removal. A steel frame canopy with a curved windshield, hinged side doors, hinged top door, and rear side windows enclose the cockpit. Fresh ram air is forced into the cockpit through an airscoop fastened to the canopy rear cap. The air is ducted to an outlet on the cockpit floor and to an adjustable outlet nozzle behind the pilots shoulder. The baggage compartment is located behind the pilot's seat, and is accessible on current Ag-Cat models, through a hinged door located in the fuselage right half center side panel. A 40G seat belt and shoulder harness installation is anchored to the fuselage structure. The wing group consists of two upper wing panels bolted to the upper wing center section, two lower wing panels bolted to the lower longerons, together with struts and wires

Grumman's G-164A Super Ag-Cat. N948X was serial number 462. Open cockpit side transparency is noteworthy, as are spray bars and nozzles.

necessary to rig the wings. The wings are of conventional two beam construction with nose ribs, intermediate, and trailing edge ribs, covered by aluminum skin on the upper surface and cloth fabric on the bottom surface. The standard fuel system on the G-164A & B consists of a 46-gallon tank installed in the upper wing center section. Increased fuel capacity (optional) is provided by adding: one fuel tank in the upper left hand wing panel for a total of 64 gallons, or one fuel tank in both upper wing panels for a total of 80 gallons. The standard fuel system on the G-164C consists of both upper wing tanks and a center section tank for a total of 80 gallons. The tail group consists of a vertical fin, rudder, horizontal stabilizer and elevator constructed of steel tubing and steel channel ribs covered with doped cotton fabric and braced with streamlined wires. A cable deflector wire extends from the canopy rear cap to the top of the tail fin to protect the fin leading edge, in the event the aircraft should encounter a wire strike. The main landing gear is attached to the fuselage just aft of the firewall. Each main landing gear wheel is supported by a steel spring leg which is bolted to an aluminum beam. The main landing gear is secured to the fuselage by means of two support plates which are bolted to the lower longerons and landing gear beam. The aircraft has a steerable tail wheel which is operated by the rudder pedals. Upon reaching full rudder travel the tail wheel becomes full swiveling. The tail wheel assembly is supported by a steel spring leg to absorb landing shock. Fuselage: The tubular steel fuselage is made entirely of SAE 4130 chrome-moly steel tubing of various diameters and wall thicknesses to meet the design requirements of each section. All joints are heliarc welded. The completed structure is completely sandblasted, using fine steel filings, and carefully inspected before priming. The priming coat is an epoxy based zinc chromate primer, while the hard finished coat is a special urethane resin based paint. After the final coat, oiling plugs are removed from the upper and lower longerons and these tubes are pumped full of corrosion preventative "Rustban" No. 397, then drained and the plugs resealed. An integral part of the fuselage is a welded-tubular truss (turn over structure) and skid shoe located directly behind the pilots seat. The pilots seat is secured by two stanchion tubes which are attached to the fuselage tubular structure. The stanchion tubes allow the seat to slide up or down to a position selected by the pilot. A shock cord assists the pilot in raising the seat. The floor assembly extends rearward from the pilot's compartment and baggage compartment, behind the pilot's seat, to the sealed dust bulkhead. Attachment fittings including lugs, gussets and brackets are welded to the fuselage tubular structure for attachment of components, formers, and fairings. The contoured main firewall, contoured dust-sealing bulkhead and canted formers provide the vertical members for attachment of the front, center, and rear side panels to each side of the fuselage. A "V"- shaped former is attached to the left side of the fuselage only, which incorporates a recessed step for entrance into the cockpit with provisions for an external power receptacle located above the step. In addition, the G164C model has a fixed stirrup type external step located on each side of the

G-164A, N948X, constructornumber 462, during spray run conducted as part of Grumman tests of

Super Ag-Cat.

G-164A, N950X, con structor number 464, equipped with a 300 horsepower Jacobs radial. The aircraft had notyet been delivered and was being flight tested bySchweizer.

fuselage directly below and in line with the pilot's seat; and, a recessed step located on the left side of the fuselage, in the middle of the front side panel, for access to the fuel tank filler cap located in the upper wing center section. . The tubular fuselage structure is the same for both G-164 A&B models with the exception that the G-164B model incorporates a tubular extension attached to the rear of the fuselage to accommodate the larger tail-fin. The bottom of the fuselage is covered by a chin skin, belly skin assembly, and rear belly skin assembly. The chin skin provides access to the landing gear beam for jacking the aircraft, and is fastened to the firewall and

belly skin assembly by means of screws and nutplates for easy removal. The sides of the forward portion of the belly skin assembly are secured by screws and elastic nuts through channel members extending from the firewall to canted formers on each side of the aircraft. The aft sides of the forward belly skin are riveted to the canted formers and to the rear belly skin assembly and stiffener. The aft flanges of the rear belly skin are attached by means of rivets to the tail-fin fairing formers. The rear side panels are attached to the dustbulkhead channels, turtle deck, tail-fin fairing formers, and rear belly skin assembly flanges. The center side panels are attached to the dust-bulkhead channels, canopy, rear

A Grumman test G-164A, N8385, construction number 878, equipped with a wing-mounted pitot boom for airspeed calibration.


G-164B, G-BDZF, constructornumber27B, operated byMilier Aerial at Wickerby in England. Centersection fuel tank is being topped-off.

G-164B, N48625, constructor number 90B, prior to delivery. This aircraft later was sent to the Dominican Republic and there registered HI-203.

belly-skin flanges, belly skin and center formers. The front side panels are attached to the center formers, upper longerons, bottom channel and belly-skin assembly, and firewall bolted to the fuselage. The G-164C model tubular fuselage is a larger overall structure which is required to accommodate the larger hopper and load carrying capability. Fuselage Panels: Each side panel con-

sists of aluminum skin, curved formers, "camloc" fasteners, and rubber sealing strips. The aluminum skin is stiffened by "V"- type corrugatlons which are sealed at each end by rubber filler blocks. The curved formers are riveted to the inside surface of the panel skin and shape the panel to match the contour of the fuselage. The" camloc" fasteners attach the panel to the fuselage. The rubber sealing strips, on the inside surface of the panel, pre-

G-164B, N6607Q, constructornumber 134B, at Merced, California on June 4, 1977. Visible in right background is sole surviving Fleetwings "Seabird". 12

vent foreign material from entering the fuselage. Canopy: The canopy consists of a steel frame, aluminum panels, molded fiberglass rear cap, windshield fairing, windshield, hinged side doors, hinged top door and rear windows. The canopy windshield fairing on the G-164A& 8 is secured directly to the hopper, and to the aft hopper fairing on the G-164C. The aft section of the canopy is riveted to the fuselage turtle deck. A faired ventilation air scoop is attached to the top of the canopy rear cap. Entrance to the cockpit is provided by the left hand fold-down door and hinged top door. Turtle Deck: The turtle deck consists of a forward bulkhead, aft frame, and aluminum skin. The skin is stiffened by two "V"- type corrugations which are sealed at each end by rubber filler blocks. The G-1648 fitted with the R975 engine has an air scoop located on the left side of the turtle deck. Wing Group: The wing group, consisting of an upper and lower wing, is comprised of a wing center section panel, four equalspan outer-wing panel assemblies, and four ailerons. The center-section panel is supported by cabane struts which are connected to the fuselage. The upper wing outer panels are bolted to the center-section and are connected to the lower outer wing panels by interplane struts. The lower wing outer panels are bolted to the fuselage lower longerons. Inter-aileron struts connect the upper and lower ailerons. The Wings are rigged by means of flying wires and landing wires. The outer wing-panel structure consists of: front and rear extruded beams, intermediate and trailing edge ribs, and nose ribs covered by "D"-shaped stressed aluminum skin sections riveted to the forward beam and nose ribs. Stressed aluminum skin panels riveted to the panel beams, intermediate, and trailing edge ribs, form the upper surface of the outer panels. Each lower wing panel is constructed with a reinforced walkway at its inboard end to allow access to the hopper and cockpit. The underside of both upper and lower panels are covered with cotton fabric, with the exception of the area within the propeller slip stream which is covered by stressed aluminum skin riveted to the panel beams and ribs. Heavy aluminum hinge fittings, riveted to the panel beams, attach the upper wing panels to the center-section clevis fittings, and the lower wing panels to the fuselage lower longeron welded clevis-type lugs. The hinge fittings utilize bushings of different lengths to allow the aft panel hinge to take the entire drag load. The rear-beam hinge and bushing are clamped up tight within the clevis lug by the attaching bolt. The front beam hinge bushing only is clamped tightly by the clevis attaching bolt. To accomplish this, the forward clevis lug is slightly wider than the rear clevis lug in order to incorporate a longer hinge bushing. The same attachment method applies to the upper panels. High-strength aluminum-alloy hinges are bolted to the wing panels for attachment of the ailerons. The center-hinge arm is bolted to the rear beam and the inboard and outboard hinge plates are bolted to the trailing edge ribs. Each hinge is fitted with a sealed roller bearing. The landing and flying wire anchor straps are of 4130 chrome-moly steel. These straps are bolted to Wing-beam

fittings. The moulded fiberglass-wing tips are attached to the outboard edges of the wing panels with screws. The upper tips are molded to incorportate the navigation lights. The underside of the upper and lower wing panels are fitted with access holes for inspection and maintenance of internal fittings. Fabric: The underside of each wing panel is fabric covered using grade-A cotton impregnated with butyrate dope, three coats of aluminum pigmented butyrate dope, and three coats of colored butyrate dope. The fabric is secured to the wing panel structure by pre-doped reinforcing tape, and rivets. Main Landing Gear: The main landing gear is attached to the fuselage just aft of the firewall. Each main landing wheel is supported by a tapered high-heat treated spring-steel gear leg. The upper end of the leg is bolted to a landing-gear support beam assembly consisting of a machined extruded aluminum alloy beam and a beam support plate bolted to each end of the beam. The assembly is attached to the fuselage by bolts, connecting the support plates to lugs welded to the lower longerons. On the G-164 A&B models a bracket is located at the center of the beam which attaches the beam to a fuselage tubular-cross member. A cantilever forged-steel axle is bolted to the lower end of each gear leg. The main-gear wheels and tires, and disc brakes are mounted on the steel axles. Provision for towing the aircraft is made by providing a tow lug inboard of each spring leg. The spring legs are of 4150 steel hot rolled, fully heat-treated and shot-peened with one coat of epoxy primer and two coats of urathane gray. A gear leg shim is utilized on the G-164A & B to hold the aft side of the spring leg against the support plate cutout. It is permissible to relocate the shim to the aft side of thespring leg if excessive toe out exists. The G164C model utilizes both a forward and aft shim. The spring leg is anchored to the landing gear beam by a stud assembly, and to the beam support plate by a support-plate baL The stud assembly, consisting of a support plate and stud, anchors the tapered end of the spring leg against the "I" beam lower cap. The stud fits through a stud hole in the spring leg and into the "I" beam lower cap. An anchor plate secured to the "I" beam upper cap by a roll pin, anchors the stud plate against the spring leg by means of connecting bolts which extend through the lower cap. A metal spacer is clamped between the tapered end of the spring and the beam lower cap. The support-beam bar secures the spring leg to the beam-support side plate by two bolts and barrel nuts located inside the support-side plate. Each axle on the G-164A & B models is secured to the spring leg by two internal wrenching bolts threaded into the axle base, and one countersunk bolt installed with a nut and washer located on the springleg side. An inner row of bolt holes with threaded inserts extend through the axle flange to accommodate the torque plate attaching bolts which secure the torque plate to the axle. Each axle on the G-164C Model is secured to the spring leg by three internal wrenching bolts, nuts, and washers. The torque plate is secured to the axle flange by means of the axle bolts. Main Landing Gear, G-164C: The main gear on the G-164C model is attached to the fuselage by the beam support plates

Dumping a load of dust, G-164B, N3629B, constructornumber 740B, utilizes its spreader unit from relatively high altitude. Wind velocity and direction are critical to such operations.

Stretched fuselage of G-164C and associated engine upgrades are this version's distinguishing features. Photo taken during the 1978 Hannover, Germanyairshow.

The ends of the support plates are fitted into the fuselage clevis lugs. T.he forward ends of the gear support plates are clamped up against a shim by a bolt and clamp-up bushing located on the outside face of the clevis lugs. The side loads are taken up by the forward clevis fittings which eliminate the need for a fuselage bracket attached to the center of the gear beam. Clamp-up bushings and shims are not installed in the aft clevis lugs, thus allowing freedom of movement at the support plate aft connection. Brake Assemblies: The Cleveland multi-cylinder disc brake assemblies are designed for use with fixed position brake discs. The cylinder assembly floats on

anchor pins that allow it to align itself with the disc, and clamp both sides of the disc with equal pressure. This floating cylinder is necessary to allow the friction linings on each side of the disc to act as caliper type clamps when fluid pressure is applied by the master cylinder. The anchor pins then act as dowels to prevent the rotation of the cylinder assembly. The disc brakes are self adjusting, eliminating the need for lining clearance adjustment subsequent to initial installation. As the linings wear, an increased volume of fluid between the brake cylinder head and piston in the wheel cylinders compensates for wear. There is never any need for brake

G-164C, N48444, during spraying operations. Additionalfuselage length of the G-164C permitted increased payload without sacrificing the aircraft's superior flight characteristics.


Caught at the moment of touchdown, Miller Aerial's G-164BTurbine Ag-Cat lands to reload during the middle of a dusting operation. Spreader, aft oflanding gear, is readily discernible.

G-164BTurbine Ag-Cat, N8499K, constructornumber 720B, during spraying operations. Long-nose of turbine powered Ag-Cats was dictated by e.g. requirements.

Another turbine-powered Ag-Cat conversion has been offered by Agri-Jet Power, Inc. The engine is a Garrett TPE-331 producing 575 shaft horsepower.

pedal adjustment regardless of lining wear. Brake fluid must be checked at intervals and added to make up for their displacement change. Unlike drum type brakes there is no spring to return the linings to a retracted position. Releasing master cylinder pressure simply removes the pressure at the wheel cylinder clamp up, allowing the disc to spin free with no danger of grabbing or locking. Therefore, there is no need for great fluid dis14

placement, which in turn allows smaller bore high pressure cylinders. Tail Landing Gear: The tail landing gear consists of a single leaf spring, tail wheel swivel assembly, tail wheel fork, and tail wheel. The tail wheel single leaf spring is attached to the fuselage by means of a single bolt at its forward end, while the aft section of the spring leg on the G-164A & B models is seated into a bracket assembly containing a

bracket bolt, which fits into an eccentric bushing. When the bolt is turned the bushing clamps the spring leg up tight against the bracket. The aft spring-leg attachment on the G-164C model consists simply of a bar and two bolts which secure the spring leg to the fuselage aft bracket. The tail-wheel swivelassembly consists of a swivel mechanism and friction damper. The tail wheel is connected to the swivel assembly by the tail wheel fork. Empennage: The empennage consists of the horizontal stabilizer and vertical tail fin. The tail fin is offset to the right 3 degrees to counteract engine torque. A cable deflecting wire is attached to the tail fin and canopy to protect the fin from being struck by wires. The tail fin is interchangeable between the G-164 A&C models whereas the tail fin on the G164B model has a longer chord and incorporates two vertical tubes which are attached to the fuselage. Horizontal Stabilizer: The horizontal stabilizer welded structure consists of a tubular leading edge, and trailing edge, center tube, tubular diagonal braces, steel sheet end caps, and channel ribs. A bolt installed vertically through the center tube attaches the leading edge of the stabilizer to a fuselage bracket. The trailing edge of the stabilizer is attached to the fuselage by bolts installed horizontally through welded lugs on the stabilizer trailing edge tube and brackets welded to the fuselage. The elevators are attached to the horizontal stabilizer welded hinges incorporating press-fit sealed ball bearings. A bracket for mounting the elevator horn is welded to the center tube. Vertical Tail: The tail-fin structure consists of welded steel tubes which form the leading edge and trailing edge of the fin and are welded to channel ribs and diagonal braces. The ends of the tubular members attach the fin to the fuselage. The G-164B model vertical fin incorporates two vertical tubes, which slide over the main fuselage tail post, and aft auxiliary tail post, where it is secured by two bolts. The leading edge tube is bolted to a fuselage bracket. The G-164A & C model fin has a shorter chord and only one vertical spar which fits over the fuselage main tail post, since the fuselage extension is not installed on the G-164A & C models. Pilot's Seat: The pilots seat consists of a frame assembly, seat pan, seat cushion, back cushion, stanchion-tube assembly, and shock cord to assist the pilot in raising the seat. The height of the seat is adjusted by means of a handle located on the right side of the seat. The aircraft may be equipped with the optional type "Spinks'" seat, which has a nylon-mesh seat and seat back. Control Surfaces: The control surfaces consist of upper and lower ailerons, aileron trim tabs, elevators, elevator fixed trim tab, elevator movable trim tab, rudder, and rudder fixed trim tab. Ailerons: Frise- type ailerons are fitted to all four wing outer panels and are driven by cables, cable sectors, and push-pull rods located in the lower wing panels. The upper ailerons are driven off the lower ailerons through inter-aileron struts. The ailerons are of simplified construction utilizing internally stiffened aluminum panels which are riveted to the top and bottom of the forward spar, trailing edge strip, and channel ribs. Nose ribs, attached to the forward spar are covered by a "D"-shaped aluminum tube. Hinge fit-


tings connect the ailerons to the hinge arms on the wing panels. Five static-balance weights are riveted to the inner surface of the aileron "D"-tube. The ailerons are interchangeable between aircraft models G-164A, B & C and between the upper and lower wing panels. Rudder: The rudder welded-steel structure consists of a torque tube, preformed nose-skin fairings, tapered channel ribs, and trailing edge, and tip consisting of a metal strip, and steel tubing. A ground-adjustable trim-tab is riveted to the trailing-edge strip, with a navigation-light housing welded to the upper end of the trailing-edge strip. The rudder is covered by doped cotton fabric. Clevis hinges are welded to the torque tube for attachment of the rudder to the tail fin. The flange at the lower end of the torque tube is bolted to the rudder steering horn. Elevators: The elevators are of welded steel structure and consist of a torque tube, preformed nose skin fairings, tapered channel ribs, and a trailing edge and tip consisting of a metal strip, and steel tubing. A groundadjustable trim-tab is riveted to the trailing-edge strip on the right-hand elevator, while the left-hand elevator trailing-edge strip is fitted with a movable trim tab operated by a push rod connected to a screw and sprocket assembly at the torque tube. The elevators are completely covered by doped cotton fabric. Clevis hinges are welded to the torque tube for attachment of the elevators to the horizontal stabilizer. The elevators are joined together by their torque tubes which are bolted on both sides of the elevator actuator horn. Flight Controls: The movable flight controls consist of the control-stick assembly, aileron control system, elevator control system, elevator trim-tab control system, and rudder control system. The control-stick assembly controls the aileron and elevator control systems. The rudder pedals control the rudder control system, and a movable arm in the cockpit controls the elevator trim tab. Engine Cowling: The engine cowling consists of removable panels, which extend from the engine-shroud assembly to the main firewall. Channel members, which are secured to the exhaust-shroud assembly and firewall serve as mounting points for attaching the top and bottom sides of the panels while the forward and aft sides of the panels are attached to the perephery of the firewall and exhaust-shroud assembly. The panels utilize "camloc" fasteners for quick removal. The panel located on the left side of the accessory section contains the oil-cooler airscoop, which directs cooling air to the oil cooler. The amount of cooling air can be regulated by a manually operated handle in the cockpit. A flexible cable assembly connects the handle to a control valve which is located inside the airscoop. The control valve is installed on G-164A SIN 1726 and up, G164B SIN 316 and up, and all G-164C models. The panels located on the right side of the accessory section contain air-exit ducts which remove warm airfrom the engine compartment. An airscoop, and carburetor air-filter housing are an integral part of the airinduction system. When the R985 engine is installed on a 26-inch engine mount an additional panel is installed aft of the carburetor air filter. An armor plate covers a portion of the bottom panels to protect the panels from

AeroMod G-1674A conversion is known as the Maxi Cat. This one is owned byKenny's Crop Dusting, Inc. ofCaruthers, California. It was photographed on October 11, 1990.

Clark Aviation, Inc. (of Bay Minette, Alabama) conversion to G-164A, N590Y, constructornumber 181 utilized a 400 horsepowerhorizontally opposed, air-cooled Lycomi ng. c


[ ~ ~

Frakes Turbo Conversion modified this G-164C, N6596K, owned byChuck Jones Flying Service of Biggs, California. It was photographed on October9, 1991. the dispersal-pump blades in the event of a blade failure. Engine Mount Assembly: The engine mount assembly is a tubular welded steel frame attached at four points to bolts extending through the firewall from the tubular frame of the fuselage. Welded to the engine mount ring are 61ugs for attachment of the R985 and R1340 engines, and 4 lugs for attachment of the R975 engine, and one welded bracketfor attachment of the engine strap. The mount ring is supported by four pairs of diagonal tubular braces welded to the mount ring. Instruments: Standard flight instruments include an altimeter, airspeed indicator, and magnetic compass. The range of the altime-

ter is 0 to 20,000 feet. Three concentric pointers indicate altitude in increments of 20; 100; 1,000 feet. A small scale on the instrument face is calibrated in inches-of-mercury. The scale is rotated by a knob at the lower left of the instrument case to equal the ambient barometric pressure. After adjusting instrument to field barometric pressure, the reading of the altimeter will indicate the actual distance of the aircraft in feet above sea level. The altimeter is connected to the same static line as the airspeed indicator. Engine Instruments: The engine instruments consist of the manifold-pressure gauge, tachometer, cylinder-head temperature, oil temperature, and oil-pressure gauge. 15

AnotherFrakes Conversion is the Turbo-Cat, N9889. This aircraft is owned by Air Rice, Inc. Cleanliness of turbine engine installation is particularly noteworthy.

Marsh Aviation offers the G-164C- T conversion also under the name Turbo-Cat. It has a 778 shaft horsepowerGarrett TPE331-1-1 0 1 derated to 600 shaft horsepower.


9= Q




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Mid-Continent Aircraft Corporation has developed a G-164C conversion known as the King-Cat. ltis powered by a 1,200 horsepowerWright R1820 radial.

Hydraulic System: The brake hydraulic system consists of two brake pedals, two master cylinders, parking-brake controlvalve, and hydraulic lines, hoses, fittings, and clamps. Operation of the brake pedals depress the pistons in the brake-master cylinders, forcing hydraUlic fluid under pressure through the hydraulic lines. The parking brake valve consists of two valves operating hydraulically independent of each other. The valves are operated by a single cam shaft which is controlled mechanically by a single operating handle. The design is such that when setting the parking brake, the brake 16

handle maybe placed in the "ON" position before or after pressing the brake pedals. Activation of the parking brake handle rotates the cam causing a poppet valve to seat on the inlet port, trapping fluid between the parking brake valve and the brake assemblies. Since the poppet valve is spring loaded, pressure applied to the brake pedals after the parking brake handle is placed in the "ON" position will lift the poppet off its seat, permitting additional hydraulic fluid to pass through the parking brake valve to increase the pressure at the brake assemblies. This enables the parking brake valve to be set either before or

after depressing the pedals .. The G-164C system contains a common reservoir which supplies both master cylinders with hydraulic fluid, whereas each master cylinder on the G164A & 8 contains an integral reservoir, filler plug and vent. 80th types of master cylinders, contain a compensating valve, return spring, piston and seals. In the released position the compensating valve is open. This allows any thermally expanded fluid within the wheel brake assembly to return to the reservoir. The brake system incorporates both rigid tube assemblies and flexible hose assemblies. Hopper: The fiberglass "Durakane"-lined hopper is secured to the fuselage by means of a stainless-steel tubular "A" frame mounted horizontally inside the hopper. Brackets welded to each corner of the "A" frame serve as pads for the hopper attaching bolts which secure the hopper and "A" frame to the fuselage. Both the G-164A & B hoppers have two stainless-steel baffles which are hung from the 'A' frame. The G-164C hopper has three baffles attached to the rods which extend the width of the hopper. The hopper vent lines consist of molded-fiberglass ducts which form an integral part of the internal surface of the hopper. A glass sightgage is attached to the rear of the hopper where it can be viewed by the pilot. Two types of hopper-loading doors are supplied: a fiberglass door which seals for spraying, and a plywood folding-type-door for dry and solid materials. The Twin CatProject: Sam Goldman initiated the Twin-Catproject and formed the Twin-Cat Corporation, with his associate G. Thomas Peterson, in 1979 to market twin-engine conversion kits for Ag-Cats. Goldman was president of Chesapeake Airways, and had previously originated the Turbo Albatross conversions, built by the Conroy Corporation. Peterson had been chief test pilot for the General Aviation Division of Rockwell International. The object of the Twin-Cat conversion was to provide an alternative to the scarce Pratt & Whitney R1340--plus tWin-engine safety--using two Lycoming T10-540 turbocharged flat-six's, which were readily available and had 2,000 hour time-beforeoverhaul (TBO). These were mounted on platforms bolted to the main longerons on each side of the fuselage. The thrust lines were canted slightly outboard and downward to improve the airflow over the wings. It was claimed that stall speed was reduced by 12 mph, and that take-off distances and rates of climb were 20 percent better than with the R1340. The prototype Twin-Cat (N8761 H, a 1975 "A" model) first flew in 1979 and had an empty fiberglass nosecone fairing, whereas, production kits included an 85 gallon fuel or chemical tank, counterbalanced by a 40 galIon tank in the rear fuselage. A FAA Supplemental Type Certificate (No. SA 1101 SO) was issued for the conversion, for which most of the test flying was done by former Lockheed test pilot Herman "Fish" Salmon. The FAA required that the Twin-Cat should be able to take off from a 2000 foot runway over a 50 foot obstacle, at a speed of 60 mph, at a maximum gross weight of 6,500 pounds. Also, to accelerate to 80 mph after unstick, throttle back the left engine, dump the load, wait 3 seconds before feathering the Hartzell three-blade propeller,

clear the obstacle, and land straight ahead, or after circling. The emergency dump valve allowed the load to be jettisoned in one-anda-half seconds to reduce the gross weight from 6,500 to 4,500 pounds (the empty weight was 3,500 pounds). In 1982 Charles O. Petersen (no relation to G. Thomas Peterson) of Petersen Aviation, Inc., Minden, Nebraska, leased Twin-Cat N8761 H from the Twin-Cat Corporation, Ormond Beach, Florida, as a backup for their six single-engined Ag-Cats. Charles asked his son Todd to fly it for the season because of its twin-engine safety. Todd considered this to be a privilege, and remembers: "It was great, except that it was difficult to trim. We flew it in the same field with the other Cats operating in groups of three. But going from one field to another, you could open it up and walk away from the conventional Cats. It would haul as much as you could put into it, but with the fuel burn the way it was (due to a cooling problem with the cowlings, which was fixed with a new cowling the next year) the fuel capacity was the limiting factor, so there wasn't much point in filling up the hopper. This would of course be different for somone working rice or some other crop where the application rate was greater. "The Twin-Cat was much quieter than the Cats powered by a 985, so if we had to spray close to cattle, we could sneak up on them and they usually didn't even know it was there. "At the end of the season, the Twin-Cat Corporation tried to sell it to us, but at $165,000 it was impossible. The problem as we saw it was the choice of engines. Had they used a 235 horsepower 0-540, instead of the TSI0-540, the sale price could have been much less, and it could have used mogas, instead of avgas. "I believethata total of three were made, and were worked that summer. One was totale.d after a wire strike, the other two (including mine) were dismantled the following year, round engines were placed on the airframes, and the STO's were turned back in tothe FAA." (On 21 December 1983, Jim Davis, of the Twin Cat Corporation, offered to make "one of the Twin Cats' available to the author to check out for a magazine article. Further correspondence was, however, returned as "Not deliverable".) Flying the Ag-Cat In 1965 I had been offered a job in Australia flying Ag-Cats, and in many ways regretted not taking it, for I had wanted to fly one, and they certainly had a good safety record. It was not until 8 December 1984, however, that I had the opportunity to fly an Ag-Catfor a magazine pilot report (published in the December, 1985 Pilot Magazine): This was a G-164A Super Ag-Cat powered by a 600 hp Pratt & Whitney R1340 engine, operated by Harmon Air Service, Inc. and flown by pilot Mike McMains from Marlin, Texas, since 1977. Mike likes flying the Ag-Cat. His only complaint, however, concerns the time the entire propeller assembly came off one powered by a Polish Pezetel engine during the first swath run across a field. He said that he instinctively pulled up, and discovered he now had an "instant glider" - but one without the glide ratio of Schweizer's other sailplane products. Not having much choice, he

An unusual modification is represented by this G-164A, N947X, constructornumber 461, converted to a British Alvis "Leonides" radial. Seen at Salinas, California on March 27, 1976.

Turbines, Inc. offers a G-164B conversion toTurbo-Cat powered bya Pratt & Whitney PT6. This particularaircraft is opera ted by Reynolds Flying Service, McRoy, Arkansas.

Unquestionably the most bizarre of the many Ag-Cat conversions is the Twin-Cat, equipped with two, side-by-side, horizontally-opposed, air-cooled Lycoming TSIO-540engines.

landed on a terraced field, tearing the main landing gear off the Ag-Cat as it reared up onto its nose, but suffering no injury himself. Mike does not know how old his present Ag-Cat (N4369, manufactured 1973) really is, but it is definately a "working workhorse" rather than a shiny factory demonstrator. I was impressed by its rugged construction almost like that of any other piece of farm machinery! It seemed monstrous as I climbed up onto the lower wing, and using the convenient hand and footholds provided,

stepped into the cockpit. The canopy roof can be unlatched and hinged up out of the way to make entry easier. The seating arrangement is like that of most ag-planes: upright, comfortable and functional, with plenty of room. The controls move very easilyon ball-bearings. Mike climbed on to the wing beside me to complete my briefing. The throttle, pitch and mixture-control quadrant is on the left side; the spray-valve is convenient for the left hand, with the solids-feeder lever below it 17

TheTwin-Catis operated by Peterson Aviation, Inc. ofMinden, Nebraska. From almost any angle itis one of the most unusual Ag-Cat configurations ever to fly.

Peterson Aviation's fleetin 1982 included, from right, N692Y, N15AZ, Twin-Cat N8761 H, N48442, and three other Ag-Cats. N 15AZcame from Guatemala with a flying wire mod. "


Two of the modified G-164As making up Rosie O'Grady's Flying Circus. This relatively unknown aerobatic team was directed by noted balloonist andparachutist Joe Kittinger.


One ofthe most colorful and highly modified ofall Ag-Cats is noted aerobaticpilot Gene Soucy's aircraft. Special systems have been installed to facilitate night-time aerobatics.

and the emergency dump handle on the left side below the instrument panel. Mike said the rudder pedals were not too easy to adjust, but we rearranged the seat cushions to enable the rudder and toe brakes to be easily operated. The chemical pump brake-lever


was to the right of the seat. (Pulled back for STOP, it is essential to prevent windmilling from overspeeding the pump when the chemical tank is empty.) It was a cool December morning and the aircraft battery was too weak to start the big

radial without the aid of jumper-cables from Mike's truck. Once it fired, however, with the usual cloud of blue smoke, it continued its rythmic idling beat with the distinctive background clanking accompaniment so typical of these faithful old engines. After warming up the engine, I taxied to the end of the single runway. Forward visibility is partially restricted by the radial engine while the tail is on the ground. I cycled the Hamilton Standard constant-speed propeller and completed the pre-take-off checks. The hopper was marked 285 US gallons (or 2,000 pounds) capacity, but on this flight was empty. I eased open the throttle, pushed the long stick forward at arms length to raise the tail, and eased it back as we accelerated down the asphalt runway. Forward visibility was excellent once the tail was up, and without a load, the Ag-Cat was quickly airborne and climbing rapidly. I eased back the power to 29 inches at 2,000 rpm and circled the airfield. Mike had recommended cruising at 2,000 to 2,100 rpm at 30 inches when carrying a load. I tried some stalls. Power-off they were docile; with power it was reluctant to stop flying - yet equally docile when it did finally break. I then tried some simulated spray passes and procedure turns at 1,000 feet, but even at this height it was difficult to avoid scattering cows which seemed to have appeared from nowhere in the fields below. Not wanting to harm Mike's public-relations program I returned to the airfield, flew a circuit, and with a trickle of power on the approach made a wheel-landing. Mike had warned me about the tailwheel s'1immying, so I held the tailwheel off for as long as possible. When it did touch the ground it shimmied, and I used the powerful wheelbrakes to stop the aircraft before taxiing back. We parked the Ag-Cat and drove to a small country cafe, where we had a barbecuedsausage sandwich and a debriefing. Mike said that the best place to practice spraying was right over the airfield, since it was used mainly by ag-pilots. On returning to the airfield we pumped some water into the hopper and I flew again. I made a series of passes down the length of the field, which had trees at one end, and wires atthe other. The air was bumpy, butthe Ag-Cat was quite stable. Stick forces were heavy during the pull-up and turn-around, but the roll-rate on this short-wing version was excellent. Mike had said that the longer-wing versions were more sluggish in roll, and thought that the best compromise was probably the 18-inch, or 24-inch STC (Supplemental Type Certicate) wing extensions on the G-164A, which was easier to operate from roads than the long-wing G1648 series. After a day's work flying the 600 hp AgCat with its heavy rudder and elevator the pilot should not have any trouble sleeping. I found that I worked up quite a sweat, even on a cool day (since both sides of the canopy were open on this aircraft I had worn a Parka jacket and hard hat). Mike remarked that the 450 hp version, with its lower weight, is lighter on the elevator. Visibility in flight is good, and although the airspeed indicator was not working on this aircraft, the speed across the field would have been 110 to 115 mph. I had definately enjoyed flying the AgCat. It was difficult, however, to say whether

the flight was more enjoyable than shooting the photographs from the ground, while Mike - the real professional - demonstrated how it should be flown! CREDITS: The author and Aerofax, Inc. would like to thank the following for contributing to this Minigraph: Alvena Pocock, Editor; Mike Amos, Photographer; Mabry I. Anderson, Author and Pilot; Brian Baker, Photographer; Betty D. Branch, Photographic Research Clerk, United States Departmant of Agriculture; Paul Chapman, Photographer; Joel P. Clark, Clark Aviation, Inc.; Jack Delaney, Ag-Cat restorer; M.D.N. Fisher, F&H Aircraft; Margie FitzGerald, Curator, National Agricultural Aviation Museum; Harold Fox, Aircraft Maintenance Instructor; Maurice E. Goff, Jr., Ag-Cat Pilot and Mechanic; Robert P. Harwood, Grumman Larry Havard, Aircraft Corporation; Maintenance Instructor; Mike Hooks, The Society of British Aerospace Companies, Ltd.; David Horton (w/special thanks for allowing us to photograph his Ag-Cat in detail) of Airlease, Inc.; Ken Keane, Joyflights, Gold Coast, Australia; Terrell Kirk, Ag-CatSales, Testing and Engineering since 1959; Joe Kittinger, V,P. Flight Operations, Church Street Station; Arthur R. Koch, AgCat Designer; Joe Kosier, Ag-Cat Sales Manager, Schweizer Aircraft Corporation; William T. Larkins, American Aircraft Historian; Joseph Lippert, Aerodynamicist, and originator of the Ag-Cat program; Lois Lovisolo, Corporate Historian, Grumman Peter Mackay, General Corporation; Manager, Field Air, Victoria, Australia; Mike McMains, Harmon Air Service, Inc.; Kathleen Meredith, Public Relations Officer, Aero Media International, Ltd.; Jay Miller, Publisher, Aerofax, Inc., who suggested this book; Jim Mills, Turbines, Inc.; Don Nance, Agri-Jet Power, Inc.; Mr. Perry, Serv-Aero; Todd Petersen, Petersen Aviation, Inc.; Chris Pocock, Photographer; Kevin R. Prosper, Photographer/lliustrator, Schweizer Aircraft Corporation; Dick Reade, President, MidDave Continent Aircraft Corporation; Roemer, Schweizer Aircraft Corporation; David Schramm, Aviation Safety Inspector, Federal Aviation Administration; Ernest Schweizer, Founder, Paul Schweizer, Director and Chairman of the Audit Committee, and William Schweizer, Chairman of the Board, Schweizer Aircraft Corporation; Gene Soucy, Aerobatic Pilot; Guy Taylor, Taylor Spraying Service; W.J. "Bill" Taylor, writer and photographer; Thomas Trissell, Trissell Flying Service, Inc.; Barbara J. Tweedt, Marketing SChweizer Aircraft Communications, Corporation; Henk Wadman, Airnieuws Nederland; William G. Walker, Jr., Vice President, Marsh Aviation Company, Tom J. Wood, Ag-Pilot International Magazine; Jay E. Wright, photographer; Joe Zumwalt, Zumwalt Aviation. Special thanks to Bill Aircraft Schweizer and Schweizer Corporation for kind permission to reproduce material supplied by them. Bibliography: AG-Cat Manuals, Grumman/Schweizer Grumman, Sixty Years of Excellence, Bill Gunston The Grumman Story, Richard Thruelsen Janes All the World Aircraft(various)

Ethiopian Airlines' Eshet's version oftheTurbo-Cat has been manufactured in small numbers to accommodate aqricultural aviation requirements in its home country.

Banner-towing is one ofthe lesser-known Ag-Cat jobs. This G-164A, constructornumber 797, is based out ofSouthbampton, England, and is registered G- WOLL (ex-G-A YTM).

Turboshaft -powered G-1640, G- TCAT (now PH- YTO) , constructornumber20. ltis seen at Lelystad, England on June 21, 1985. Low and Slow, Mabry Anderson Soaring with the Schweizers, William Schweizer Wings Like Eagles, Paul Schweizer

About the Author: At age 13 Nick Pocock became an "aeroplane spotter". Armed with notebook and box-camera, he cycled along narrow English lanes to the many local aerodromes. At age 17, he learned to fly in Tiger Moth biplanes through the Air Training Corps, and later joined the

Royal Air Force Volunteer Reserve as a cadet pilot. Since then, his flying has included several years of competition and exhibition aerobatics, and instruction. He was the sole representative of the United Kingdom in the Second World Aerobatic Championships, at Budapest, Hungary, in 1962. He then flew three seasons of cropspraying in Texas, Nicaragua, and Mississippi. Later he flew part-time: gliding (instructing and towing), aerial photography, seaplanes, and skywriting. Pocock has writ-


G-164B, G-BFTN, oonstructor number204B, powered by a 450 horsepowerPratt & Whitney engine. This aircraft later was registered PH-APR.

Author Nick Pocock has spent many hours in the Ag-Cat's spartan cockpit.

in Texas. Nick teaches at Texas State Technical College and is a member of the Institution of Mechanical Engineers, Antique Airplane Association, Experimental Aircraft Association, and OX5 Pioneers Historians.

n I~




,I II I'




British G-164A, G-BCXI, constructornumber 1414, under the loading chute at Lincolnshire, near London. Spreader is visible aft oflanding gear.

DIMENSIONS: MODEL G-164A Wingspan (Upper) 35' 11-1/8" (Lower) 34' 0" Horiz. Stab. Span 13' 0" Overall 23 ' 10" Length * Height 11 ' 0" Prop. Ground Clear. 10 3/4" (min.) Prop. Dia. 108" (max.) Tire Tread 96" Dihedral Chord Stagger GrossWt. Wing Area Aileron Area Stab. Area Elev. Area Fin Area Rudder Area



42' 2-3/4" 42' 2-3/4" 40' 6-3/4" 40' 6-3/4" 13'0"


25' 7" 11 ' 0"

30'0" 11 '5" 179/16 "

3deg. 58" 35deg. 45001b. 328 sq. '

10 3/4" (min.) 108" (max.) 96" 3deg. 58" 35deg. 4500 lb. 391.8sq. '

108" (max.) 100" 3deg. 58" 35deg. 6300 lb. 391.8sq. '

31.4 sq. ' 19.3 sq. ' 26.1 sq. ' 9.9 sq. '

31.4sq. ' 19.3sq. ' 26.1 sq.' 17.97sq. '

31.4sq. ' 19.3sq. ' 26.1 sq.' 9.9sq. '

10.0sq. '

10.0sq. '

10.0sq. '

* 450 HP (Long Mount) 24' 3"1 600 HP (Long Mount) 24' 3 5/8

British G-164A, G-A TVY, constructornumber 287 (ex-N725YIGY-JDP) ofAviation Spraying Services Ltd., Rochester, England. This aircraft laterbecame N8285ID-FADAlPH-ZLD.

ten the book, Oid W.O. Custead Fly First?, and numerous magazine articles about aircraft, and other aviators. He has spent six


years researching the Ag-Catstory. Nick and Alvena have been married 30 years, have four children, and live on a ranch


CONTROL MOVEMENTS, G164A, B, C, MODELS: Ailerons 2]0 (±2°) Up 131/2' (±2°) Down Elevators 25° (±2°) Up 15° (±2°) Down Rudder 33° (±2°) Left 2]0 (±2°) Right ElevatorTrim Tab 18° (±2°) Up 13° (±2°) Down

WEIGHT OF COMPONENTS: MODEL G164A G164B G164C Upper Wing Panel (each) 1441b. 1851b. 1851b. Lower Wing Panel (each) 141 lb. 1831b. 1831b. Center Section 871b. 871b. 871b. Upper Wing Fuel Tank (each) 181b. 181b. 181b. Fuselage 500 lb. 500 lb. 762 lb. Main Landing Gear 265 lb. 2651b. 445 lb. Tail Surfaces (w/rigging) 781b. 781b. 891b. 250 lb. Hopper 120 lb. 1201b. Power Plant Installation R985 10171b. 10171b. n/a R1340 12401b. 12401b. 12551b. R975 N/A 10651b. n/a Power Plant installation consists of complete power plant detachable at the main firewall including the propeller. POWERPLANT: (less accessories) R985-25,27 R985-39, 39A, T1 83, 148 R985-AN-1,3 R985-T182 R1340-AN-1, S1H1, S3H1 R975-46/PA2 Exhaust System Accessories Propeller 2830/AG-100-4S 12D40/G101A-12 12D401AG-100-2

685 lb. 450 HP 6741b. 668 lb. 6531b. 600 HP 865 lb. 525 HP 7171b. 31 lb. 40 lb. 172lb. 177lb. 1841b.

G-164A, GY-JDR, constructornumber288 at Rochester, Englandduring 1966. Earlier, ithadbeen registered N726Y. Subsequently, it was registered G-A TVZlN8286,/D-FACU.

G-164A, CF-UOF, constructornumber 411. A large number ofAg-Cats have found their way into Canada to accommodate agricultural requirements there.

French-registered Ag-Cats are relatively commonplace in lightofthe agricultural activity associated with grape growing and otheragrarian activities. This G164A, F-BHHY, was photographed at Montdidies on May29, 1971.


Fire-fighting Ag-Cat conversion. Fire-fighting aircraft are a prized commodity in France as forest fires are a common problem there. This G-164C, F-BZJH, constructornumber 11C, original/y was registered F- WZJH and N6S87K. Photographed at Montpel/ier during August of 1994.

i ~'

G-164A,D-FADA, constructor number 287, has since become PH-ZLD. It was photographed at Seppe during 1977.

G-164A, D-FACU, ofAgrartlug Works in Germany. Lower wing tip modification is noteworthy.

G-164A, D-FACU, constructornumber 288, has been through numerous owners and associated registrations including N726Yand N8286.

G-164A, PH-2LD, constructornumber 287, at Seppe on AprilS, 1977. Curled tips reduce turbulent airflow and improve spray/dustpatterns.

G-164A, PH-DAP, is one oftwo operated byDutch Air Sprayers of Siddeburen, Northern Hal/and.

G-164A, 1260, at Dekelia Air Base, Greece on November 8, 1980. Military markings on Ag-Cats are unusual and rarely seen.



G-1648, PH-APR, constructor number2048 powered by a Pratt & Whitney engine of450 horsepower. Increased area of vertical tail is readily discernible. The aircraft was photographed at Midden-Zeeland during 1981.

A small number ofG-164As were manufactured for use in Panama. Three aircraft, including HP-346 and HP-347, are seen at the Schweizer factory.

Pratt & Whitney -powered G-1648, PH- TPR, constructornumber 3328, at Midden-Zeeland during 1981.

These ten G-164As were part of a fleet sale to Guatemala. They are seen prior to delivery, already bearing Guatemalan civil registration markings. Registrations visitle, from left to right, include: (TG) FIR-F; FIQ-F; FIP-F; FIO-F; FIN-F; FIM-F; FIL-F; FIK-F; FIJ-F; and FII-F.

G-164D, PH- YTO, constructornumber02D. Dorsalfin extension and long nose peculiarto the turboprop Ag-Cats are noteworthy.

G-164A, ZS-KIT, constructornumber585 ofAvex Air in South Africa. Photo was taken during 1974.


G-164A, ZK-MEW, at Queenstown, New Zealand on December25, 1991. Aircraft is painted brightyellow with black checkerboard on nose and cowl.

Spanish-registered G-164A, EC-8AN (ex-N605U), constructornumber 334, being blessed in Portugal before entering service.

Newly delivered G-164C, PZ-U8L, at Surinam. Slightly stretched fuselage of this version is readily apparent.

Newly delivered G-1648, YV-144A, for Venezuela. Size ofG-1648 vertical tail is distinctive feature of this variant.

G-1648, SE-GEP, constructornumber 1878, for Sweden. This aircraft originally was registered in the U. S. as N6660Q. Readily discernible under fuselage, just aft ofmain landing gear, is spreader unit. Spray bars have been removed.


G-164, N1 0211, constructornumber 11, operated by Atwood's as a sprayer. Photo taken in California during December of 1989. This aircraft is powered by the original Continental 670 radialfound only on early Ag-Cats.

G-164A, N711 WW is one ofatleastthree Ag-Cats modified for use in noted balloonist Joe Kittinger's Rosie O'Grady's Flying Circus. The aerobatic team's aircraft have been distinctively painted and equipped with 600 horsepower engines.


G-164, N10218, constructornumber 18, of Streeter Flying Service, photographed during October of 1990. Short-coupled fuselage of G-164A is particularly noticeable when this model is compared to the later, longer G-164C.

G-164A, N655Y, ofP. M. Dusters at Durham, California during October of 1991. Aircraft is being loaded with dust. Spreaderassembly is readily visible under fuselage. Engine is kept running during process in order to shorten down time.


G-164A, N7807, constructornumber 1012, of Miller's Flying Service, Colusa, California, during October of 1991. Airfoil shape to spreader assembly under fuselage is readily discernible.

G-1648, N3629F, constructornumber 7458, of Haley Flying Service, Tracy, California, during October of 1990. Aircraft is essentially stock and is configured for spraying. Spray bars are mounted immediately aft of wing trailing edge.




Gene Soucy's unique G-164, nicknamed the Show Cat, has been modified to incorporate a number of unusualfeatures including a second cockpit in place of the normal hopperinstallation. Visible on the wingtips are pyrotechnic devices fomight aerobatic routines.

G-164B turbine conversion, N6617K, constructornumber 392B, is owned by Vince Crop Dusters of Buttonwillow, California. Because of light weight of turboshaft engines, turbine conversions to stock G-164s require long engine mounts to counter effects on c.g.


With engine running, G-164A, N458Y, constructor number 104, is loaded with dust while pausing on a strip near Highway 20 outside Sutter, California on April30, 1966. The aircraft is powered by a 525 horsepowerPratl & Whitney R1340.

G-1640, G-BHHY, constructornumber 020, reloads during a dusting operation in England. Aircraft is owned and operated byMilier Aerial. Self-contained unit on truck considerably reduces aircraft down-time during reloads.


Ken Keane's G-164A, VH-CCK(Sister Hanna) modified to accommodate PK3500 floats. It is seen at Palm Beach, Queensland, Australia.

Ken Keane's G-164A, VH-CCK, is possibly the only Ag-Cat equipped with floats. Ventral fin for improved directional stability is noteworthy.

Remains of G-164B, N6689Q, constructor number 420B in Jarmon Auto junkyard in Phoenix, Arizona during October of 1988.

G-164A, N716Y, constructornumber 278 at Richvale on April 5, 1966. Cockpit structure, obviously intact, savedpilot's life.

G-164A, N652U, constructornumber 388 following a freak windstorm at Schweizer's Elmira, New York factory. Damaged aircraft like this were either written-offor, when feasible, repaired to as-new condition.







Grumman/Schweizer Model G·164 Ag.Cat

Length: 24ft. 6 in. Wingspan: 35 ft. 8 in. Height: 10ft. 9 in. Horizontal Tail Span: 13 ft. 0 in. Landing Gear Track: 8 ft. 0 in. Empty Weight: 2,179 pounds Gross Weight: 3,600 pounds

Grumman/Schweizer Model G·164A Ag.Cat

Length: 23ft. 1Oin. Wingspan: 35ft. 11.1 in. Height: 11 ft. 0 in. Horizontal Tail Span: 13 ft. 0 in. Landing Gear Track: 8ft. 0 in. Empty Weight: 2,201 pounds (W670-6A) Gross Weight: 3,600 pounds (W670-6A)


Grumman/Schweizer Model G·164B Ag.Cat

Length: 25 ft. 7 in. Wingspan: 42 ft. 2.75 in. Height: 11 ft. 0 in. Horizontal Tail Span: 13ft. 0 in. Landing Gear Track: 8 ft. 0 in. Empty Weight: 3,145 pounds (R985) Gross Weight: 6,075 pounds (R985)

Grumman/Schweizer Model G·164C Ag.Cat

Length: 30 ft. 0 in. Wingspan: 42 ft. 2.75 in. Height: 11 ft. 5 in. Horizontal Tail Span: 13ft. 0 in. Landing Gear Track: 8 ft. 4 in. Empty Weight: 3,025 pounds Gross Weight: 6,075 pounds



Grumman/Schweizer Model 450B Ag-Cat

Length: 24 ft. 1.62 in. Wingspan: 42 ft. 4.39 in. Height: 11 ft. 5.9 in. Horizontal Tail Span: 13 ft. 0 in. Landing Gear Track: 8 ft. 0 in. Empty Weight: 3,625 pounds Gross Weight: 5,200 pounds

Grumman/Schweizer Model G-164B Turbine Ag-Cat

Length: 26 ft. 11.9 in. Wingspan: 42ft. 4.5 in. Height: 11 ft. 5.9 in. Horizontal Tail Span: 13 ft. 0 in. Landing Gear Track: 8 ft. 0 in. Empty Weight: 3,140 pounds (typical) Gross Weight: 9,000 pounds (typical)



~'Jtl~LJJ [,.,5

JC::Ci '

"))Ion" to,;

G·164A/B/C Aircraft Stations


IC""t", lin" 1 !'.,,,,,h'.l" ,.~i I """t)



IC"ntc·, line of ~"n"I~'J" T~il 1'"')

G-164A instrument panel is kept purposefully simple to avoid maintenance headaches.

Tu rbo Ag-Cat instrument panel is optimized to accommodate the engine instrumentation required for turboshaft propulsion.

G·164C Instrument Panel

G·164A and G·164B Instrument Panels


1''' "'"""l~",, sudo", WI; wing St,),lon

G-164A instrument panel. Padding around instruments is for pilotprotection in the event ofan accident. Panel is basic with little in the way ofadvanced navigation gear or communications equipment.

Special panel arrangement found on Gene Soucy's highly modified airshow Ag-Cat. Aerobatic routine is visible to right.

(C""tc' line
Aerofax Minigraph 11 - Grumman-Schweizer AG-CAT

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