Mk1 eyeball; Su-27 is considerably longer, wider, and higher. Su-27’s frontal and side area is considerably larger and its top area is slightly larger. No one can be 100% certain, but all these translates to greater volume to me.
That chart is wildly inaccurate, and produced before schematics of the T-50 from patents were released, or satellite photos of the J-20 were examined. The J-20 is nowhere near that large, since its length is revealed to be something like 20.5 meters long. Also, the T-50’s fuselage is more voluminous than the diagram suggests. Here’s an accurate frontal view of both the T-50 and F-22.
Be that as it may, its a way smarter solution vs the F-22 solution.
I’ll would say it’s only 50% empty hole of that we see on F-22, maybe even less. And i do not think the PakFa store fuel in that area anyway.
And the extra drag from this on the PakFa is very small.This design solution is a mean to increase the internal volume for fuel and larger MWB.
Clever indeed.
Dude, you are making way too many unqualified statements. “Smarter solution” is a meaningless term. You don’t know what the structure of those bays look like, and the net aerodynamic difference compared to F-22 SRAAM bays is difficult to quantify. For instance, placement of T-50’s SRAAM bays may help volume distribution for area ruling but may present additional sources of interference drag and shockwaves. But unless we have actual flight test or wind tunnel data, the overall effect is extremely difficult to calculate, much less eyeball. So just stop, unless you know all the design trade studies that Sukhoi performed.
Tandem main weapon bays aren’t even unique to the T-50. The prospective EMD F-23 would also have tandem bays, though arranged slightly differently.
Not T-50 but Su-34;
Assuming T-50 positions internal bay towards the downside of the aircraft, there are actually no holes in T-50’s design.
IMHO, dealing with bending moments is easy, as long as there is seperation between weapon bays. However with change of AOA, pressure center also changes, and with only one area to strengthen the fuselage (space between weapon bays), it can also produce severe torsional forces spanwise. Sukhoi appearantly attempted to correct this by controlling pressure center (by levcons) and still unsatisfied so its improving structure for torsional stresses. Reasoning: Adding a top plate to connect longerons would have little affect in bending resistance, however it would wastly imrpove torsional stiffnes (so that wings front will not bend upwards together with the fuselage when pulling high Gs)
You may be right. Pictures of unpainted T-50-1, -2, and -4 shows spanwise reinforcement plates on both the top and bottom fuselage. I was under the assumption that they are for handling bending loads (especially since the bottom plates are rather short but have considerable span), but they may also be there to cope with stresses from torsion, since skin plates are generally for handling shear loads. In any case we don’t know the thickness of those plates. That said, the placement of the weapon bays as well as the launching mechanisms mean that fewer full depth spanwise bulkheads can run through the middle of the fuselage (has to run between the weapon bays). But the fuselage seems to be overall deeper than the Su-27, so it may not be as severe as I first thought, and as you’ve pointed out, the height between the engines for the Su-27 is also low. Also (correct me if I’m wrong), I believe the fuselage longerons were reinforced separately by additional plating down the aircraft’s spine behind the cockpit.
I must say that it’s quite a beautiful aircraft.
Disclosure: I’ve only taken an introductory aircraft structures course so far, so I’m still not proficient in the area. Perhaps my views will change as I get further along in my degree.
There is no physical way to form the shock with the desired angle, without moving the shock-forming geometry properly. Even if F-22 can generate multiple oblique shocks (Claims aside, I would bet some very good money that it cannot) such inlet simply can’t control them. Excluding the single design point, oblique shocks will either end up inside the inlet, out outside; reducing pressure recovery either way. Let them classify all they want, this is the nature of things.
A surface “turning into” the flow can act as a compression ramp and can generate multiple shocks, though without actively controlling the surface geometry the shock angle would be difficult to control. We don’t know the precise geometry of the inlets, though based on the particular diamond intake geometry I believe it would be external compression. But going by djcross’ posts, it would seem that the F-22’s inlets have some kind of mechanism that can limit spillage drag.
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