Russian Military News, Reports, Data, etc.
- Thread starter tphuang
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So, the aircraft profile is lovely, the frontal view is spot on, but I do NOT like that forward sweep, more of a design statement than an aerodynamic statement, it will probably work fine. Its appearance is un-orthodox, reminds me of something from the Rutan Bros., prolly works well, but not so aesthetic as to "draw" you too it??.
Forward-swept wings make an aircraft harder to fly, but the advantages are mainly down to manoeuvrability. They maintain airflow over their surfaces at steeper climb angles than conventional planes, which means the nose can point higher without the aircraft going into a dangerous stall. In addition, their aerodynamic properties change less between subsonic and supersonic flight than swept-back wings, meaning that the Su-47 is well suited to transonic flight - in other words, at speeds close to the sound barrier.
The Su-47 was indeed a highly maneuverable aircraft, capable of pulling 9 Gs, however, its immediate predecessor, the Sukhoi Su-37, was capable of pulling 10 Gs. So it's not clear whether a forward swept wing has any real positive impact on maneuverability.
However, stall characteristics are very different. Air tends to travel towards the rearmost end of the wing. On a standard configuration (Rear-swept wing), this of course moves from the wing root to the wingtip. On a forward-swept wing, however, this moves from the wingtip to the wing root.
As a result, the dangerous tip stall condition of a backwards-swept design becomes a safer and more controllable root stall on a forward swept design. This allows full aileron control despite loss of lift, and also means that drag-inducing leading edge slots or other devices are not required. With the air flowing inwards, wingtip vortices and the accompanying drag are reduced, instead the fuselage acts as a very large wing fence and, since wings are generally larger at the root, this improves lift allowing a smaller wing. As a result maneuverability is improved, especially at high angles of attack. At transonic speeds, shockwaves build up first at the root rather than the tip, again helping to ensure effective aileron control.
Forward-swept wings make an aircraft harder to fly, but the advantages are mainly down to manoeuvrability. They maintain airflow over their surfaces at steeper climb angles than conventional planes, which means the nose can point higher without the aircraft going into a dangerous stall. In addition, their aerodynamic properties change less between subsonic and supersonic flight than swept-back wings, meaning that the Su-47 is well suited to transonic flight - in other words, at speeds close to the sound barrier.
The Su-47 was indeed a highly maneuverable aircraft, capable of pulling 9 Gs, however, its immediate predecessor, the Sukhoi Su-37, was capable of pulling 10 Gs. So it's not clear whether a forward swept wing has any real positive impact on maneuverability.
However, stall characteristics are very different. Air tends to travel towards the rearmost end of the wing. On a standard configuration (Rear-swept wing), this of course moves from the wing root to the wingtip. On a forward-swept wing, however, this moves from the wingtip to the wing root.
As a result, the dangerous tip stall condition of a backwards-swept design becomes a safer and more controllable root stall on a forward swept design. This allows full aileron control despite loss of lift, and also means that drag-inducing leading edge slots or other devices are not required. With the air flowing inwards, wingtip vortices and the accompanying drag are reduced, instead the fuselage acts as a very large wing fence and, since wings are generally larger at the root, this improves lift allowing a smaller wing. As a result maneuverability is improved, especially at high angles of attack. At transonic speeds, shockwaves build up first at the root rather than the tip, again helping to ensure effective aileron control.
Heh! Heh! Heh!, if the forward sweep flew so much better, it would have most certainly been incorporated into both the US and Russian aircraft designs long before now?? the answer to stall propogation, and maintaining roll control is "wash-out" where the out board section, housing the ailerons is washed out and angle of attack reduced on the outboard section by twisting the leading edge downward by design and construction to maintain airflow over the tips ailerons, with NONE of the hegative/costly need for solutions.
What does your wash out increase for using a swept wing do for induced drag?
One of the first swept wing aircraft had negative sweep: Ju-287 heavy bomber.
The Hansa Jet ( ) had negative sweep in order to use a mid wing design with the cabin wholly in front of the wing carry through structure.
The problem with the old forward swept wings was that it costs more structure weight to prevent flutter. By using fibre reinforced plastic for the main wing structure you can avoid that penalty. It might make sense to use such wings for smaller aircraft up to the size of Hansa Jet or a little larger and this trainer might be the progenitor of such aircraft. Let's not say what was good enough for my father is good enough for me but look for ways to improve.
As you have noted the increased aeroelasticity of the forward swept wing will indeed increase flutter, unless its rigidity is increased. Carbon fibre is one solution, and works quite well in most applications, but while it can be very simple and cost effective. It does introduce a need for extreme precision in order to maintain that strength, as well as a very clean working area and a large autoclave to cure the carbon fibre resin.
Now none of these are problems per se, just different, and if what you produce is beautiful and cost effective, all is good. This little aircraft is different looking, no doubt its kool, but its not particularly attractive, and I rather doubt it flies any better? although roll control could be enhanced, and at the lower speeds it will travel, that may be a need..... it just doesn't have a very attractive overhead planform, I think the wing may be a little smallish, with an increased chord near the root, and a neat taper it could have been at least a little more attractive, and that still sells airplanes. LOL
Just pulling your chain a little to keep you on your toes?
b787
Captain
I can not tell you up to what degree the Russians fixed the problem of forward swept wings, but i have watched videos where they claim they did, if that is the case SR-10 will be the first operational aircraft to feature them.
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b787
Captain
well it will not be the first, the Hansa was the first but perhaps it will be more successfulI can not tell you up to what degree the Russians fixed the problem of forward swept wings, but i have watched videos where they claim they did, if that is the case SR-10 will be the first operational aircraft to feature them.
