by Bill Lavender
ALBANY, GA -- If there ever was any doubt about Thrush Aircraft, Inc. starting up the production line of the Thrush aircraft, let that doubt rest. After a visit to the factory, AgAir Update has become readily aware that new Thrush aircraft are about to grace the sky again.
With a work force of 62, Thrush Aircraft, Inc. principals, Payne Hughes and Larry Bays, already have six new Thrush aircraft, three each of the 660 and 550 models, sold to individual owners. The first two new Thrushes off the assembly line, a 660 and a 550, will be at the NAAA convention in Reno, December 8-11.
Thrush Aircraft will be introducing some of the most innovative changes to the Thrush line at Reno, changes not seen by the industry in many years. During the aircraft's two-year hiatus from production, feedback from the field has been addressed, bringing the best Thrush ever to the marketplace. Will the ag-operator recognize this new version of the ag-aircraft icon?
The Principals - Payne Hughes, a tall and impressive man, knows how to turn around a company. For the past 25 years, his mission in his career life has been taking small companies (over 15) many on the down slide, and making them profitable. Hughes made his good fortune in the printing and publishing business. Starting in the early 1980s, Hughes took a 17-employee company and grew it to more than 900 employees. When he sold his company, its gross revenues were in excess of $100 million annually. Hughes is well positioned with his experience and capital to guide Thrush Aircraft. Larry Bays stands out with his ability to crunch numbers. Bays owns an accounting firm in Albany, the same company that kept the books for Ayres Corporation from 1977 to 1998. He has an in depth knowledge of the costs of operating Thrush Aircraft. Bays works daily at the factory as president of the company.
Infrastructure - A telltale sign of a company's ability to stay in the marketplace can often be detected by the infrastructure of the facility where it manufactures its product. The Thrush factory fell into disarray after several years of neglect and two years without producing a new aircraft. When Thrush Aircraft took over the facility, one of the first things on the agenda was to bring the factory facility back to a first class operation. The company is investing $3.5 million to accomplish this renovation. It will include a new $700,000 roof and a 10,000-square foot area which will be refurbished for a dedicated CNC machine shop and a five-axis plaining mill. When completed, the shop will be climate controlled. The offices are being refurbished as well.
Although the roof repairs are in progress, the factory refurbishment has taken second priority to getting the production line going. Of the ten possible assembly stations, the line currently has four stations operating. This will accommodate the production schedule of two aircraft a month. However, adding a minimum number of employees to the line stations, the production could double monthly if needed.
The Changes - Any ag-pilot's curiosity will dictate the questions, "What are these changes? How do you improve one of the finest ag-planes ever built?" Keep in mind, nothing has ever been built that could not be improved upon. The Thrush is no exception. Returning to the ag-aviation fleet, it will be more powerful, more docile, more reliable and bigger! And it will be competitive, in both productivity and price.
The Formidable 660 - A host of improvements are in store for the new Thrush 660 owner. Even though it will continue to be called the 660, vacuum bag technology for its hopper construction, along with a new design gate box bumps up the capacity to 680 gallons for spraying and up to 750 gallons for fire fighting operations. Vacuum bag technology in fiberglass construction allows for a more even wall thickness, saving about 100 pounds of weight, while creating a larger interior with the same exterior dimensions.
Any concerns about the "look" of the old 660 won't carry over to the current model 660. With a new nose bowl that is more streamlined, longer straight fuselage lines from the cockpit forward and a taller tail with more surface area, the 660 will catch any ag-pilot's eye.
If eye catching is good, then performance is better. The 660 will have either the PT6A-65 or the -267 engine. Certification in 2004 will allow the pilot to utilize the full potential of these engines, developing 1,230 shp and 1,350 shp respectfully. More performance enhancing changes include closing in the aft portion of the fuselage, reducing air disturbance around the tail section.
Changes to the tail section will improve the 660's forward lateral stability. The vertical stabilizer and rudder have been extended at the top by six inches. Another rib was added and the trailing edge extended approximately two inches to accommodate the width of the tips, giving the overall structure several more square inches of surface area.
The 660 will be versatile, being able to quickly change from a spraying role to a fire fighting role. The hopper throat will have a spacer that drops the rear of the gate opening three inches more than the front, allowing for a better flow pattern for dry materials. This spacer between the hopper throat and the hopper gate also allows for the quick disconnect of the spray hopper throat and quick reconnect of the Hatfield Fire Bombing throat. This fire bombing hopper throat is hydraulically operated, can interface with GPS units and adds about 70 gallons to the aircraft's capacity.
Thrush Aircraft has addressed its wing spar problems head on. The 660 center beam and spar configuration has been designed to make the outer wing panels lighter and incorporate extra strength using the heat treated 4340 steel spar caps and 4340 center beam. The extra strength of this heat-treated 4340 steel spar cap allows for the reduction of steel doublers and inboard steel webbing, saving weight. The 660 wing has been static tested to 14,150 pounds. The factory is confident the new and improved center spar section will never have an AD.
The Versatile 550 - Once known at the Ayres 510, this sturdy ag-plane has grown up in size and at the same time become more nimble with improved lines from the cockpit forward. The pilot's view in the 550 cockpit is now a straight line from the windshield over the hopper lid (taken from the 660) to the prop. The sides of the aircraft forward of the cockpit are straighter. The 550 has inherited many of the improvements given to the 660. It has a more aerodynamic aft fuselage, enclosing the rear portion to improve airflow at the tail section. The wing spar problems have been addressed, which incorporates the new 29,000-hour lower spar caps on all new production aircraft and can be retrofitted to the existing Thrush fleet. The spars are made from 4340 heat-treated steel and the design of the lower cap allows for the reduction of steel doublers and webs, saving weight on the new 550.
One of the most noticeable changes to the 550 is the spring steel main gear; gone are the days of biscuits and trunnions. The installation of spring gear on the 550 required lowering the gate box to accommodate an aerodynamic fairing from forward of the pump to the hopper gate opening. This, along with the improved vacuum bag construction of the hopper and the 660's hopper top adds forty-nine more gallons of capacity. The hopper also has rudder pedal wells for full rudder pedal deflections.
Standard equipment for the 550 is the 29,000-hour lower spar cap. This lower spar cap can be retrofitted to all previously built 510 Thrush aircraft. Retrofitting the new lower spar cap eliminates all ADs for the wing spar of the Thrush. For those pilots who need more fuel, as an option, an additional 57.5-gallon wet wing bay tank can be added outboard of the standard fuel cells of each wing of the 550.
What to expect - In its heyday, from August 1973 through August of 1976, there was an average of five Thrush aircraft produced each week: 250 aircraft a year. During the late 1980s through 1998, typically 50 Thrush aircraft were built each year. In 2001, only 14 aircraft were built and from August of 2001 until now, no Thrush aircraft have been built. There has always been support for Thrush parts. It would seem likely a Thrush Aircraft production run of 24 aircraft a year is a reasonable estimate, especially with any pent up demand from the last two years. To further promote sales, Thrush Aircraft has developed a factory-participating lease program for new owners worldwide, either an operating or financing lease.
"We are returning to our core business, aerospace contract work and building Thrush aircraft," says Milt Humphries, company General Manager. With the level of quality control (QC) demonstrated by Thrush Aircraft, the factory is recognized throughout the aerospace industry and is poised to negotiate outside contracts. These aerospace contracts will only strengthen further the Thrush position in the ag-aviation marketplace.
Inquiries have been made about a 400-gallon machine. According to Humphries, should the demand require it, the factory will produce it, but most likely it will be a 440-gallon aircraft since it will have the spring steel gear and the extra deep hopper gate box. Most likely a TPE-331-6 turboprop engine, or even a PT6A-15 or ą34AG engine, will power the 440-gallon machine.
The intent of this article is to whet the appetites of ag-plane owners and pilots. If you have specific questions, by attending the NAAA convention in Reno you can meet Payne Hughes, Larry Bays and Milt Humphries, and get answers to those questions.
Milt Humphries points out how the 660 tail wheel is now attached at a different angle, taking a load off the tail wheel assembly and making it easier to swing the aircraft. The tail wheel assembly and the spring gear can be retrofitted to both 660 and 510 model Thrushes.
The assembly line advancing forward at Thrush Aircraft, Inc.
A view of the stainless steel hopper throat. The center piece will be removed before installation. Another similar piece only one inch thick toward the front and three inches thick in the rear will provide this divider between the dual hopper throats and drop the rear of the gate opening allowing for a better flow of dry materials.
The Thrush 660 center section with the standard 228-gallon fuel system, or the optional 340-gallon system can be installed.
With vacuum bag technology, both the 550 and the 660 model Thrushes save 100 pounds, while at the same time creating a stronger and larger hopper.
The new 660 nose bowl mold is set on top of the older 660 mold. Note how the design of the new nose bowl has less vertical length. The propeller spinner fits with its trailing edge aerodynamically in line with the nose bowl.
The 29,000-hour lower spar cap is on the left, obviously larger and stronger than the older version that is on the right.
The Hatfield Fire Bombing hopper gate is hydraulically operated for fire bombing operations. It is an option for the 660 model Thrush.
The rudder on the 660 was extended six inches at the top, between the tip and the first rib.
The 550 gear support beam is fabricated on a CNC four axis lathe from a large single piece of 7075 T6 aluminum.