Graham Warwick/Washington DC
Kathmandu is a long way from Albany, Georgia, but the power of the Internet has brought Ayres' Loadmaster to the attention of an operator in the Nepal capital, and others in places as far afield as Papua New Guinea and South Africa.
Enquiries from these, and others, have left president Fred Ayres a little surprised, but pleased, by the interest generated by his utility turboprop. Having a launch order from FedEx for 50 aircraft, plus options for another 200, certainly helps, but Ayres seems to have tapped a rich vein of demand for a simple, unpressurised, fixed-gear aircraft from operators wanting something bigger than a Cessna Caravan I.
Initially, the LM200 Loadmaster is being developed as a freighter, designed to carry a payload of up to 3,400kg over a range of almost 1,100km (600nm) but, spurred by customer interest, Ayres already has passenger/cargo, air-tour, floatplane, surveillance and military-transport variants on the drawing board. "There is a market out there for an aircraft larger than the Caravan," Ayres concludes.
When Ayres acquired Rockwell's Thrush Commander agricultural-aircraft line in 1977, there was already a design for a single-turboprop utility aircraft, the Bushmaster, which used the powerplant, wing and tail of the Turbo Thrush. Plans were put on hold by the recession of the early 1980s. "Then the Caravan comes along and it's almost identical in size," Ayres recalls. The company decided against competing with Cessna and diversified, taking on subcontract work for Boeing and McDonnell Douglas as well as for FedEx.
The utility-aircraft design was dusted off in the early 1990s. "The Caravan had done well, and there was a possible market for an aircraft of the same size," explains Ayres. Discussions began with FedEx, but the package carrier wanted an aircraft bigger than the Caravan, which it already operated in large numbers. The Caravan has a 3,630kg take-off weight, so Ayres decided to move up to 5,670kg, the maximum allowed for a single-engined aircraft. This was still not enough for FedEx, which wanted an aircraft able to carry its "demi" cargo containers.
Ayres pushed the gross weight up to 8,620kg and sought an exemption from the US Federal Aviation Administration to allow single-engine cargo-only operations at this weight, "-but a spate of commuter accidents had hardened the FAA's position", Ayres says. To overcome this limitation, a "twin-barrel" propulsion system was conceived, with two engines driving a single propeller via a combining gearbox, enabling the aircraft to be certificated to the higher weights allowed for a twin-turboprop. "This is a twin-engined aircraft," says Ayres.
The original plan had been to power the Loadmaster with a single Pratt & Whitney Canada PW127 turboprop. Two options were considered for the dual-engine propulsion unit: a P&WC/Soloy PT6 Dual Pac and the LHTEC CTP800 - a turboprop derivative of the T800 turboshaft powering the Boeing/ Sikorsky RAH-66 Comanche helicopter. FedEx chose the engine, and picked the relatively unproven CTP800. Ayres believes that the decision was based on this engine's later technology, lighter weight and lower fuel-consumption than those of the PT6.
LHTEC, an AlliedSignal/Allison joint venture, is responsible for delivering a certificated propulsion system to Ayres. The CTP800-4T twin-barrel powerplant is rated at 2,000kW (2,700shp) and consists of two turboshaft power-sections and a GKN Westland-developed combining gearbox, driving a Hamilton Standard six-bade propeller. Propulsion-system tests will begin in the second quarter of 1998, leading to first production deliveries in the second quarter of 1999. FedEx has contracted directly with LHTEC for engines to power the 50 Loadmasters it has on firm order. Ayres, meanwhile, has placed a separate contract for 100 shipsets for aircraft sold to other customers. Ayres says that he will "-let the market dictate" whether the PT6 Dual Pac is also certificated eventually on the Loadmaster.
Engine evolution
Evolution of the powerplant has influenced the Loadmaster's shape, which is a classic example of form following function. As propeller diameter was increased to almost 4m, Ayres explains, the nose was moved up, resulting in a profile where the cockpit sits "747-style" atop the fuselage. The constant section of the fuselage is sized to accommodate four demi or LD3 containers, and there is additional storage space under the cockpit and in the aft fuselage. "There are more cubic feet in the Loadmaster than in the Douglas DC-3 or Fokker F27," Ayres says.
One design goal was for an empty weight less than 50% of the gross weight. "Empty weight is 47%," says Ayres, despite the Loadmaster having an all-metal airframe designed to US Part 25 transport-category rules, rather than the Part 23 commuter-category regulations which usually apply to an aircraft of this size. Ayres believes that the use of Part 25 design requirements will enable the company, at some later stage, to apply for an exemption to operate at take-off weights some 1,300-1,600kg higher.
The high-set wing is all new, with a 20% thickness-to-chord ratio at the roots allowing deep spars to reduce weight. Large translating Fowler flaps allowed Ayres to reduce wing area by over 9m2 from that of a conventional wing. The 70kt (130km/h) stall speed is a design point, while the 205kt maximum cruise "fell out", rather than being a requirement, says Ayres. The power available gives a 365m take-off distance at maximum weight, while the single-engine performance will be "incredible", he claims.
The design of the Loadmaster has been driven by FedEx's requirements, but the resulting aircraft is not limited in its applications to just package carrying. The fuselage has been sized to accommodate containers, but is "-perfect for four-abreast seating as comfortable as in any commuter", says Ayres. The aircraft will be certificated to carry 19 passengers, plus 2,200-2,700kg of cargo in the rear cabin, and Ayres expects most non-FedEx Loadmastersto be sold in this combi configuration.
The basic freighter version will have aft cargo and forward entry doors, but no windows. The combi version will have windows, emergency exits, seat tracks and air vents. An optional cabin liner will include overhead baggage bins. The cargo version will be certificated first, followed by the combi, then Ayres expects to develop a variant with clamshell rear-fuselage doors. This would allow the Loadmaster to carry a pick-up truck and a minivan, to meet demand for such an aircraft in the Alaskan market, Ayres says.
Other versions being planned include the Tourmaster, for the Grand Canyon tour market, with 19 side-facing seats and bigger windows. The Searchmaster is a proposed surveillance variant, with equipment which could be rolled on and off through the aft cargo door. There is a floatplane version on the drawing board and Ayres has already offered a military-transport derivative. The military LM250, with a 2,500kW CTP800-50 powerplant, was offered to Australia as a possible de Havilland Caribou replacement, but was "-kicked out".
Derivatives
The development of derivatives will be made easier as the Loadmaster's fuselage is to be built in sections, with most changes restricted to the aft portion, allowing variants to be assembled on a common line. Ayres plans to produce the aircraft at a factory to be established within 160km of the company's Albany, Georgia, plant. Plans call for the Albany factory to produce detail parts for shipment to "two or three" major subcontractors, which will fabricate airframe sections, then deliver them to Ayres' new plant for final assembly. The "firewall-forward" section housing the powerplant will be produced at Albany.
LHTEC will provide complete propulsion systems, while Honeywell will supply SPZ-5000 avionics suites ready be plugged in. Ayres is close to naming suppliers of integrated fuel, electric and landing-gear systems. This risk-sharing approach will limit the cost to Ayres of certificating the Loadmaster to $25 million. The company expects to break even after100 aircraft, and already holds firm orders for more than 70, including those for the FedEx contract.
Two certification-test aircraft will be built at Albany, with the first to be flown in mid-1998. Certification is planned for the third quarter of 1999 and deliveries to FedEx are to begin with the eleventh Loadmaster, in December 1999. Thereafter, four aircraft a month will be produced, two of them for FedEx. "We have a lot to do in the next two years, but I feel pretty good about it," says Ayres.
Source: Flight International
