The Israeli air force has re-engined one of its Boeing 707s and plans to put new powerplants on more of its old transports.
The Israeli air force operates 13 707-300s in a variety of roles, including in-flight refuelling and electronic intelligence. Some of these are still powered by the Pratt &Whitney JT4A-11 turbojet.
Project manager Capt Ami Zango says the JT4A-11 has been replaced with the P&WJT3D-3B turbofan. The re-engining project is the first in which the air force has acted as the prime contractor. The air force's engineering department was responsible for programme development while the work was performed by the Bedek division of Israel Aircraft Industries (IAI), which is responsible for707 maintenance. By replacing the pylons, the re-engining called for only minor modifications to the aircraft, says the air force.
The prototype 707 conversion was fitted initially with only two JT3Ds, on the inboard pylons, while the outer pylons retained the older engines.
"The first test flight was very successful," says Zango. The re-engined 707 has a 20% lower fuel consumption and a better rate of climb and improves take-off performance on hot days.
Source: Flight International
