THE TUPOLEV Tu-144LL supersonic flying laboratory is being prepared for the next portion of its flight-test programme, now that an initial series of eight flights, three of them supersonic, has been completed.

The tests are part of a joint US-Russian programme being undertaken from Zhukovsky, near Moscow. In the first five sorties, Tupolev fulfilled all the requisite subsonic tests initially planned for 14-15 flights. "We try to make each flight more capacious, more intensive," explains Tupolev chief designer Aleksandr Pukhov, "as some 150 million roubles [$30,000] worth of fuel is consumed in each flight." The maximum speed achieved during the supersonic sorties was Mach 2.0.

Pukhov has decided to ground the aircraft for six to nine weeks before conducting scientific experiments, to enable additional equipment such as on-wing pressure sensors and other missing test equipment to be installed.

The entire test programme plan had called for 32 flights (including the subsonic testing), but Pukhov states that testing will now be fulfilled in fewer missions.

"I think I need 12 flights to complete the six experiments agreed with my US partners," he says. Boeing confirms that, partially for funding reasons, the total number of flights has been halved to 18. The remaining ten test flights are due to begin by early September.

Then the Tu-144 could be ferried to California, USA, to carry out the seventh experiment which will examine sonic booms. "When we were planning our experiments, I insisted that the seventh experiment be postponed because of its complexity. Even now we are not sure whether to perform it or not," Pukhov explains.

US sources believe it is unlikely the Tu-144 will be ferried to California for tests. "It is something that Tupolev is trying to promote with NASA, but there is nothing in Boeing or NASA's plan to bring the aircraft over here," says the US manufacturer.

Source: Flight International