plus the splitting of 2 intakes & exhaust nozzles is pretty inefficient with a single 90mm, even it was possible

Don't know about the F-15C, but the F-18E has plenty enough thrust. A lot has to do with the ducting, too.

Originally Posted by v8truckin

I just want a Freewing Mig29

MiG-35 plz.

Double cockpit and way more cool.

Originally Posted by SU-4ever

The real SU-35 and similar craft use very THIN airfoils for supersonic flight but not symmetric at all, that I can assure you

The camber of the foil plays its part in post stall characteristics, you need to understand how an airfoil works first.

At low angles of attack airfoils do curve the flow around them... to a point and according to their shape. That part is pretty intuitive.
Then, flow directly in contact with the airfoil makes a layer called boundary layer. At first this layer is smooth (leading edge) but as long as the flow progresses over trailing edge, and when angle of attack is INCREASED, it 'looses' energy and thickens, then it separates or detaches from the airfoil. When the b.layer detaches, the flow stops seeing the airfoil shape but rather the shape of the detached flow. The zone of detached flow creates an enormous drag, and post stall flight characteristics has to do with how this detached flow works its way around the body-wing of the design.

Back to airfoils, airfoils with more camber create a higher adverse pressure gradient which makes flow detach earlier.
Also THICKER airfoils, specially those with more rounded leading edges (Check 3D planes) help the boundary layer stay attached longer. Also the chord plays its part, the longer the chord, the sooner the flow will detach starting from trailing edge (Flow loses more energy as it travels the wing). Then there's the tridimensional effects (Wingtip vortices) that affect more or less depending wing aspect ratio and wing swept...

And finally hyper-lift devices come into play such as LERX on the SU-35 that create powerful low pressure vortex that attach to the wings and delay b.layer separation increasing lift up to 20% in high alpha... then there's leading edge flaps that make the leading edge appear to the incoming flow in a smoother way so that it also delays detachment... fowler flaps that use energy from the flow under the wing to enhance the attachment energy of the flow on top and improve flap effectivity... and the list goes on forever.

But in the end you need to understand 2 things:
First that you want to enhance lift at high angles of attack for good high alpha performance... BUT second, most of these meassures might have a negative effect on aircraft's lateral stability! So, what you feel when flying, you might feel more comfortable due to the things that worsen high alpha efficiency but actually improve stability at high angles of attack. It is indeed a complex subject and you pretty much can only study it experimentally or with CFD... but you can not easily believe the results that come out of a CFD analysis... if you don't actually test it in some way or another to verify computer data

Briefing:
The post stall characteristics that we notice on our SU-35 are mainly influenced by wing planform+aspect ratio + LERX.
Once the flow detaches, the profile shape has very little contribution because the wing behaves almost as a flat surface.
There, leading edge flaps could play a very important part in helping improve those results but since our airfoil is not as thin or flat as the real SU-35, the cambered-thicker profile freewing chose pretty much does the same for high alpha as the leading edge flaps would.

Whoa, did you understand anything of that?
If 20% hit home I'll be satisfied with myself.

thanks for the comprehensive explanation!!! I think I got most of it

Interestingly, re the 3d airfoils.. they have really changed heaps in recent times in our models.. Not so thick & round leading edges anymore - much thinner & sharp LE .. As you were saying flow detaches almost entirely in very high angles of attack & planform & aspect ration take over (does tail moment then come into it a fair bit too re lateral stability? guessing it does) - but anyway, I think designers must have found these thinner airfoils do fine with post-stall 3d as well as the sharper LE... that's both with & without aerodynamic washout devises like vortex generators on the outboard sections

Well, there's one thing to very thin airfoils... They can function like thick ones at times.

Flow detaches too early but then re-attaches, causing a circulation bubble atop the leading edge.

The more problematic ones are medium-thickness profiles, because these create the same bubble but it explodes suddenly, causing a total detachment of the flow over the wing with no warning. Thin airfoils instead, the bubble grows bigger with angle of attack causing vibrations so the pilot has a physical warning way before it reaches stall, at which point it detaches completely like the medium thickness foil.

Which may be the tell with this models foil design. Tip stall potential in the alpha for this swept wing where the foil goes from thick root to thinner medium tip foil may fit why it breaks loose very quickly with higher wing loading. May be an explanation for some unrecoverable stalled flat spins just at the right speed and wrong AoA for everything to suddenly go off.

Mind you this model still handles the prestall way better than most. Wing shape may be.......

Wing planform + LERX + low AR it is, most likely.

Originally Posted by SU-4ever

Wing planform + LERX + low AR it is, most likely.

true but I still find it to do better than say the FW F-18. May be just bias...

"Back to airfoils, airfoils with more camber "

Jandro........How about an add on to your piece about stall progression on delta wing forms. The SU 35 is,after all, virtually a delta wing plane.

I'd like to know why mine "waggles" at a particular sink rate as if it was stalling and recovering on alternate wing tips. If I don't throttle up or nose down it just starts to sink faster.

As in a flat drop or what's the flight condition? Cause a lot of things can trigger an oscillation.

[QUOTE=locharrow;33325867How about an add on to your piece about stall progression on delta wing forms. The SU 35 is,after all, virtually a delta wing plane.

I'd like to know why mine "waggles" at a particular sink rate as if it was stalling and recovering on alternate wing tips. If I don't throttle up or nose down it just starts to sink faster. [/QUOTE]

not really.. It's quite far from it IMO. Nothing close to even tailed deltas like the Pak FA & f-22.. those delta designs seem to be MUCH more controllable in high alpha (without flight control systems of course).

What happened to Natasha crash video?

Do the Su35 is easy to control?

Originally Posted by teshiecat

not really.. It's quite far from it IMO. Nothing close to even tailed deltas like the Pak FA & f-22.. those delta designs seem to be MUCH more controllable in high alpha (without flight control systems of course).

True. The Sukhoi wing is just a swept broad wing with a slightly higher AR than designs considered tailed deltas. In fact tailed deltas have varied definitions. At one point that was in reference to one like the A4 design where the stabilator sat on the vertical tail almost over the wing where the elevons of a delta wing would normally be.
The F4 progressed to move the tail stabilator back further though the engine and weight sits further forward mainly on the wings. Thus they had adverse yaw and roll and instead of having ailerons counter each other, one aileron went down on one side and a counter air brake popped up on the other side. This was because it still had the effects of a true delta wing effecting it's stability.

There is the idea that the wings shape in a triangled delta is a delta wing but the definition goes further where the wing is placed relative to the overall weight distribution.

Euro or Mirage where the engine is near the elevons vs and delta wing positioned further forward like with a F22 acting more like normal wings only with a lower AR just having the delta shape. But because it's far enough forward pitch must then be left to the separate tail stabs again positioned around the engines. The blend between both world's is the PakFa where it's delta form starts far enough forward but aft enough that the wings ailerons are far enough aft to be elevons or have enough of a pitch moment for them to be used with pitch at certain speeds.

Tailed deltas the original definition of the type are prone to spin stalls because the delta wing tends to blank their air flow in pitch up. The Phantom, A4 and other similar designs like them were know for this.

So I think the reason for the repeating comparisons and corrections of what a tailed delta is is because it's had varied definitions between laymen and aviation.

Originally Posted by healthgood1

Do the Su35 is easy to control?

very stable when trimmed properly. But it also can have high maneuver rates so it's not a beginner model.
The stall concerns mentioned prior is in the extreme, the prestall associated with 3D or scale air show maneuvers.