Never ending headache
This is the actual duct:
Do you see the engine has a high mounting (denoted by thick lower circular structural stringer sections) at least a quarter of the compressor is mounted above the wing) then the duct bends down sharply – denoted by the thickening upper circular structural stringer sections (in this port duct it bends around the MLG bay and offsets to the left but this is not visible).
Above is the lateral offset (that orange crate is vertically aligned with the upper, outer corner of the intake).
Very important to note here how the lower cowling departs significantly from the upper – a source of much confusion/misrepresentation:
http://forum.keypublishing.com/attachment.php?attachmentid=238845&d=1435841679
As can be seen from the top pic the duct extends thru a significant part (if not all) of that elongated yellow panel in front of the cowling:
http://sukhoi.org/img/gallery/wallpaper/1_29_01_10/1002101_80.jpg
…so as the actual duct is under that yellow panel, then it’s a very funky and revolutionary design (short & aggressive bend in the duct):
Incidentally, the height of the MLG wheel is approximately the same as the compressor, so one can easily visualise how much of the comp will be visible (now that we know precisely where the engine is mounted and what direction the duct takes).
That thing you refer to as “engine facet” (from that infamous ‘PAK-FA in the night’ pic, cannot be reconciled as the compressor either vertically, nor laterally. These observations (and most importantly the CAD screenshots) confirm insiders’ and the official patent claims of the existence of S-ducts.
Which begs the question of that ‘thing’ in the intake, what is it? Pay attention!
As intimated before, it is a device to facilitate high pressure recovery to the compressor (near 100%)- the fixed vanes are installed downstream of the bend and precisely orientated to match the static pressure field. In that infamous PAK-FA pic you can even see the same shade of grey duct behind the vanes as precedes them – this is the aggressive bend.
The T-50 would have a flight time of a few seconds if this guide vane structure wasn’t installed.
The beauty of it is that it doubles as a “radar screen” known as ‘Device 9/Устройсво 9’ in the official patent “set straight in the intake, offset and partially obscuring the [engine’s] guide vanes”- clearly neither the compressor nor duct are “set straight” vis-a-vis the intake.
The “radar screen” function of the vanes negates the need for a ‘long S-duct’ to absorb/neutralise incident and reflected radar waves. I’ll leave it to more learned members to explain the precise mechanics of the RCS of intake cavities but, clearly, it is a World apart from a radar ‘blocker’ in the conventional sense as installed on 4G legacy fighters.
The advantages of the design compared to conventional S-ducts are a huge reduction in system length (and hence weight) and overall a more integrated fuselage design as demonstrated by the T-50’s lower profile compared to the F-22/35/J-20 ‘fatties’.
It is advances in CFD software’s predictive accuracy and raw computing power that have made this revolutionary S-duct a reality* and I believe these design elements will be replicated in upcoming US 6G contenders.
*http://forum.keypublishing.com/showthread.php?126959-The-PAK-FA-News-Pics-amp-Debate-Thread-XXIV&p=2125742#post2125742
Pics 1&3 ℅ Mr. Paralay.
My point was not to put down the design. You are being more pedantic so I’ll play along, OK, it is not the engine face, nonetheless, the design required a certain solution, which is harder and more complicated than the F-22’s solution; therefore the second part of my statement linked to the T-50’s top speed stands. They wouldn’t have gone for such a complicated solution if it didn’t offer some advantage. The lift/enlarged engine bay argument is logical, but in -my humble- opinion, not enough. I think they may had in mind that the plane would be a good deal faster than the raptor.
Sign In
