Raisbeck Commercial Air Group has begun flight tests of a Boeing 727-200 fitted with newly developed engine tailpipe forced mixers. The tests are aimed at achieving certification of the company's heavy gross weight (HGW) Stage 3 system by March 1999.
The US company says the tests are attracting "serious interest" from major operators of the HGW -200s, with maximum take-off weights ranging from 81,700kg (180,000lb) to 95,100kg. The company's HGW Stage 3 system is based on aerodynamic modifications devised for the earlier increased gross weight (IGW) kit, plus the addition of Raisbeck's proprietary external tailpipe mixers.
Delta Air Lines, Mexicana, United Airlines and several cargo operators are believed to have requested proposals from Raisbeck, which declines to confirm the identify of individual airlines.
Raisbeck director of airline requirements Richard Tait says: "Cargo operators are very interested and we are looking at a big opportunity to kick it off." First deliveries are due in April 1999.
The company hoped initially to have the HGW kit available in late 1998, but says the effort was put back as it concentrated on certification of its standard (SGW) and IGW Stage 3 systems. The latter was purchased for 52 aircraft by American Airlines, which accepted its first three kits last month.
Flight tests are now under way with Hamilton Aviation at Tucson, Arizona, using a Sun Pacific-owned 727. As a result of initial findings, the company says that it now plans to certify the HGW kit with flaps set at 30° for landing, compared to the planned 28° used for the IGW kit.
The SGW kit, by comparison, is certified for 25° flaps and increases landing field length by up to 400ft (120m) depending on weight. The IGW kit, on the other hand, imposes a penalty of up to 200ft in length. The HGW kit is not expected to make any difference to landing length.
Source: Flight International
