Su 47

Fuselage
The Su-47s fuselage is oval in cross section and the airframe is constructed mainly of aluminium and titanium alloys and 13% (by weight) of composite materials. The nose radome is slightly flattened at the fore section, and has a horizontal edge to optimise the aircraft's anti-spin characteristics.


[edit] WingsThe forward-swept midwing gives the unconventional (and characteristic) appearance of the Su-47, earning it the nickname of 'devil' and 'slingshot'. A substantial part of the lift generated by the forward-swept wing occurs at the inner portion of the wingspan. The lift is not restricted by wingtip stall. The ailerons - the wing's control surfaces - remain effective at the highest angles of attack, and controllability of the aircraft is retained even in the event of airflow separating from the remainder of the wings' surface.

The wing panels are constructed of nearly 90% composites. The forward-swept midwing has a high aspect ratio, which contributes to long-range performance. The leading-edge root extensions blend smoothly to the wing panels, which are fitted with deflectable slats on the leading edge; flaps and ailerons on the trailing edge. The all-moving and small-area trapezoidal canards are connected to the leading-edge root extensions.

The downside of such a wing design is that it produces strong rotational forces that try to twist the wings off, especially at high speeds. This twisting necessitates the use of a large amount of composites in order to increase the strength and durability of the wing. Despite this strengthening, the plane was initially limited to Mach 1.6. Recent engineering modifications have raised this limit, but the new limit has not been specified. Nevertheless, it is rumored that the Su-47 prototype recently suffered some manner of wing failure during testing. As a result, Western analysts speculate that Sukhoi engineers have restored the prototype to a conventional swept-wing layout.[2] Apparently, the engineers reached the same conclusions with regard to the viability of a forward-swept layout as their counterparts at Grumman did twenty years ago with the X-29.[2] Therefore, it is likely that any derivative production aircraft based on Su-47 research will utilize a conventional wing layout.