Burbank Aeronautical (BAC II) says the cruise performance of its Boeing 707-320B demonstrator is "dramatically" improved thanks to winglets installed before a transatlantic flight to Paris, where the modified aircraft was on static display at June's Paris air show.
Although the company is evaluating precise performance figures, the winglets helped generate "substantial" fuel savings during east and west-bound crossings, it says. Equipped with the company's newly developed Stage 3 hushkits, the 707's average fuel consumption is around 6,820litres (1,800US gal)/h. Following the installation of the winglets, this dropped by "around 200 gallons" says marketing director Tom Maguire. The company cautions, however, that the results are preliminary and adds that the east-bound crossing was made at 43,000ft (13,120m).
BAC II says final performance figures could also be altered by changes to the weight of the production standard winglets. The prototype winglet set is made from heavier gauge carbon composite and each weighs around 190kg (425lb), whereas the production winglets will weigh 225-250lb each, says Maguire. The current flight test phase for the US Federal Aviation Administration is "more concerned with safety of flight" issues, rather than any effects on performance. Pending a successful test series, BAC II hopes to obtain an FAA supplemental type certificate in "late August or early September," says Maguire.
As with its parallel McDonnell Douglas DC-8-50/61 hushkit/ winglet programme, BAC II is not signing customers until the STC is obtained, but says "people are lining up" in the interim. The company estimates the market for the 707 work includes up to 160 non-military 707s and around 200 US military aircraft.
BAC II hopes to obtain an STC for its DC-8-50/61 Stage 3 hushkit "by late December" following the start of flight tests. The DC-8 was expected to begin engine cell test work at Edwards AFB, California on 6 July as part of the certification programme. "This is a sister programme to the 707 in the sense that there will be 75-80% commonality between the hushkits."
Source: Flight International
