Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!att!cbnews!military
From: convex!gray@uxc.cso.uiuc.edu (Ron Gray)
Newsgroups: sci.military
Subject: viffing
Message-ID: <7956@cbnews.ATT.COM>
Date: 5 Jul 89 12:37:41 GMT
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From: convex!gray@uxc.cso.uiuc.edu (Ron Gray)


>From: bryden@vax1.acs.udel.edu (Christopher F. Bryden)
>So, can the Soviet pseudoequivalent (Forger) vector in forward flight?
>From what I understand, it has a pair of jet engines near the nose of 
>the aircraft that balance rear engine outlets that can vector rearward 
>(throught 90 degrees) to downward.
>
>Chris

The Yakovlev Yak-38MP "Forger" differs from the design of the Yak-36 in that
it has only one main lift/cruise engine (the Yak-36 had two). The Lyul'ka 
AL-21 Turbojet generates a takeoff thrust of approximately 17,600 lbs.
with total takeoff thrust of approximately 16,500 lbs. 

VTOL capability is provided by 2 Kolesov turbojet lift engines foward aft
of the cockpit, each lift engine generates approximately 7,700 lbs of 
thrust.

Though the lift jets incorporate limited vectoring in the fore/aft plane,
their centerlines are angled to the rear and the thrust component must
be maintained by rotating the main engine nozzles to the 100 or 105 deg
position, well forward of vertical.

Because of the necessity for the thrust of the lift jets to be balanced
by the full vectoring of the real engine nozzle, it was believed that 
the aircraft was limited to strictly VTOL, and thus incapable of STOL or 
VIFFing.

Recent evidence however suggests that the aircraft is indeed capable of
VSTOL. VIFFing though may still be inhibited as some sources believe that
the procedure for use of the forward lift jets for takeoff and landing is 
fully automated, and thus could not be used in combat.