Except the inlet capture area matches that for the AL-31, not for the F135. Geometry changes anyways are most likely to occur in the DSI sizing, not in actually increasing the size of the inlets, although that'd help, but require a substantial redesign and stealth reverification.
Aerodynamics thread
- Thread starter siegecrossbow
- Start date
Please provide citations for what the Al-31 inlet capture area should be, and show us your measurements to demonstrate that’s what the J-20’s inlets are sized for.
3-5 years is the optimistic projection. WS-10 took around a decade to mature and 16 years to finally equip its target fighter (J-10). That said, China has a lot more money to throw at problems than it did a decade ago. Recent breakthroughs with WS-10 and WS-20 are making me more optimistic.
More importantly, China has a whole lot more experience with modern engine production, and much more advanced capital equipment and production techniques too. I don’t think what happened with the WS-10 is going to repeat. There’s no hope for China to catch up on engines if the WS-10 is the standard timeline new Chinese engine designs follow.
Original research.. I'll put it back when I get home. Btw, what are the accepted dimensions of the J-20 again? 20.4x12.95? Too lazy to look it up, and away fron ny machine right now.
About right. I *think* the wingspan is actually a bit wider, but not by much. Maybe 0.1 or 0.2 meters.
I have 20.88 x 12.95. Actually, my old measurement was 1m2, I need to redraw up the inlet sizing figures for the J-20, F-35, and Su-27. IIRC it should be on secret projects, I was trying to argue that enhanced inlet size could allow the J-20 to supercruise on WS-10 when the Su-27 couldn't.
Not so fast... more thrust only equals more mass flow if specific thrust does not increase from altered engine cycle parameters. Between the WS-10 and WS-15 these certainly will change though, because to enable supercruise the latter is going to have markedly lower BPR and higher turbine inlet temperature. Depending how much lower/higher, the WS-15 could easily get 10% more thrust out of the same mass flow as the current engines (which are in the 13 to 14tf ball park) from the BPR decrease alone. For reference, IIRC the Izd.30 is said to have 25% more specific thrust than the AL-31F - that sort of improvement would take WS-15 into the 17tf region without any increase in airflow whatsoever. If a minor mismatch with the current engines were accepted (it's always a compromise between low speed and high speed requirements anyhow), the existing intake could suffice no problem at all.
I'm more assuming the WS-15 will have both efficiency improvements (higher core temperature) and higher mass flow requirements. The WS-15 is believed to be somewhat larger than the WS-10s to begin with.
We still have to consider the DSI differences between prototype (2011 iirc) and production J-20s. It stands to reason that the original DSI was intended for a WS-15 that was late, while the new DSI was built for AL-31 and WS-10s.
And then there's the question of how the inlets were tuned on the Su-57, i.e, were the engines tuned for greater mass flows than the Su-27? I'll need to take a look at that as well.
That's not how it works and this isn't even accurate anyway. Those measures are off. J-20's intake area is not roughly the same as the Flanker's. Also different geometry intakes must have quite an affect on all these claims.
Your conclusion from your theory is not correct even if the theory is.
Edit... sorry people have pointed this out in greater detail.