[quote name='Austin' date='03 February 2010 - 06:05 AM' timestamp='1265156828' post='103867']
Indeed most of the internal weapons will be carried between the engines , how does one minimise the pressure drag co-efficient in this case ?[/quote]
Supersonic drag (aka pressure wave drag) is generally minimized by ensuring that the cross section area along the length for the whole aircraft be key constant (the reason why supersonic aircraft fuselage is coke bottle shaped, narrow in the mid section because the wings take up cross section area. It is my suspicion that they have not bulged the space between the engines because the whole aircraft may have lot of cross section area in that vital section. Of course if the fighter mission is to log external weapon it means it will not fly supersonic while that payload is lugged, but after discharging the external payload, it will fly supersonic without too much excessive pressure drag penalty.
Minimizing pressure drag is a multi variate optimization problem, and teh designer will trade off various features to balance all priorities. No straight answer to how to minimize it, without compromising some other performance consideration.
Looking at the pcitures and line drawing ti is difficult to point out RF LO weakness for these radar bands, because the design looks very stealthy from all aspects, except dead behind the engine. But that narrow axis is weak for all stealth aircraft's except B-2.
VHF radar stealth will IMHO be the poorest. No different from F22 and F35.
Indeed most of the internal weapons will be carried between the engines , how does one minimise the pressure drag co-efficient in this case ?[/quote]
Supersonic drag (aka pressure wave drag) is generally minimized by ensuring that the cross section area along the length for the whole aircraft be key constant (the reason why supersonic aircraft fuselage is coke bottle shaped, narrow in the mid section because the wings take up cross section area. It is my suspicion that they have not bulged the space between the engines because the whole aircraft may have lot of cross section area in that vital section. Of course if the fighter mission is to log external weapon it means it will not fly supersonic while that payload is lugged, but after discharging the external payload, it will fly supersonic without too much excessive pressure drag penalty.
Minimizing pressure drag is a multi variate optimization problem, and teh designer will trade off various features to balance all priorities. No straight answer to how to minimize it, without compromising some other performance consideration.
Quote:They have mentioned ability to carry some internal weapons side ways ( 2 small AAM ) near the wings but thats highly doubtful L-band
What is your opinion on the structural shape of PAK-FA , are they capable of all aspect stealth which takes care of most band i.e. L,S,X and VHF ?
Looking at the pcitures and line drawing ti is difficult to point out RF LO weakness for these radar bands, because the design looks very stealthy from all aspects, except dead behind the engine. But that narrow axis is weak for all stealth aircraft's except B-2.
VHF radar stealth will IMHO be the poorest. No different from F22 and F35.