Design Flaws with the Iranian Stealth:

First off, the aircraft is much too small. Take a look at the shots where someone is sitting in the cockpit. The aircraft is tiny – perhaps two-thirds or less the size of an F-35. What this affects primarily is range and operating endurance, because there’s just not much room for fuel. A “stealth” aircraft won’t use external tankage (drop tanks, etc.) to extend the range in a combat situation because of the penalty to the signature-reduction efforts made on the aircraft. (Provision for external tanks would be made for “ferry” flights, but in combat and with this tiny aircraft they’d have to be dropped so far away from the target that the pilot might not make it back.) Similarly, all weapons would be carried internally for the same reason, further reducing the volume available for fuel. Even modern jet engines are thirsty. As sized here, the range and combat endurance (especially air combat) of this aircraft probably wouldn’t be enough to perform any useful mission.

Second, also related to fuel volume and sizing: Stealth aircraft (especially fighters) reduce their infrared signature by “dumping” heat from electronics and other systems into the fuel, rather into cooling air that is then dumped overboard. The F-35 already has problems with sustaining a sufficient combat endurance because of this – a certain amount of fuel can only hold so much heat before it starts getting too hot to be safe. This “Qaher-313” is so much smaller than the F-35, that the problems would be magnified – its smaller amount of fuel would reach heat saturation that much faster.

Moving on from sizing, the other major “telltale” that this is a movie-prop-style fake is the air intakes. There are two major problems here. One, again, is size. Those two tiny intakes couldn’t capture enough air to feed a fighter-sized jet engine, even a modestly-sized one for a small aircraft such as this. They’re absurdly small.

Even more critical is their location and shape. Note that they’re above a sharp leading edge “strake” on the fuselage. The edge on such a shape is designed to produce a strong vortex of air on its upper surface, energizing the flow and keeping that flow attached to the broad fuselage when the aircraft is flying at a high angle of attack (nose up relative to the airflow), such as combat maneuvers, takeoff, and landing. But what we have here is the engine air intakes positioned such that they’ll directly ingest the vortex from the strake edge, rather than letting it flow over the fuselage. Jet engines like smooth intake flow. They do not like turbulent, swirling, disrupted flow as the engine would see in this design. What would be likely to happen, the moment the pilot pulled back hard on the stick, is that the intakes would ingest the vortex and the engine would then undergo a compressor stall – and simply quit. Which really isn’t a behavior you’d want in a combat aircraft, or any aircraft for that matter.

Moving on to other details:

Airfoils – On both the canard and the main wing, the airfoils are far too thick. Whoever designed this may have some experience with radio-controlled models (which is supported by the video, which appears to be an R/C model flying, despite the dubbed-in “jet” sounds), but they have no experience designing transonic or supersonic aircraft. Many of the features of this airplane suggest that it’s intended for supersonic flight, but the airfoils are entirely too thick for that application. Look at the F-22, F-35, Typhoon, T-50, SU-35, or any other modern supersonic combat aircraft. Their wings and tail surfaces are very thin. This wing and tail are thick like a Cessna, 787, A330. Yet this is supposed to be a fighter. It’s a glaring contradiction.

Pitch Control Surfaces – The aircraft is configured as a close-coupled canard. The size of the space provided for the engine nozzle (the engine does not appear to be installed on this display model) suggests a fairly large engine for the size of the aircraft (which only makes the sizing issues worse), so we could expect the center of gravity to be well-aft, something that is supported by the position of the main landing gear. That means the aircraft would be statically unstable in pitch (nose up/nose down), or at the very least neutrally stable. This condition is common in modern air-combat fighters, because it enhances maneuverability. The flight control system computers keep the aircraft flying smoothly by manipulating the flight controls many times each second – if they didn’t, the aircraft would literally swap ends in-flight faster than the pilot could compensate. It’s like having an arrow with the feathers at the wrong end. On all such aircraft, observe that the pitch flight control surfaces, whether they’re aft as in the F-22 or F-35, or forward such as in the Eurofighter Typhoon or Saab Gripen, are “all-moving” surfaces. The entire “tail” surface moves. This is to afford sufficient control power to not only maneuver the aircraft, but to give the computers enough control power to keep the aircraft flying smoothly in extreme conditions of angle of attack. Now let’s look at the “Qaher-313”. It’s hard to tell, but there are a couple of views that show that the canard is fixed, with a movable control surface (elevator). That’s a common control surface arrangement for canard R/C models and small manned “homebuilt” aircraft, all of which are completely stable in pitch. But again, it makes no sense in a modern fighter aircraft that appears as if it’s going to be statically unstable. Another glaring contradiction.

Still another is the wonky “drooped” wingtips. This is a design feature designed to do two things – make the aircraft unstable in roll (good in a fighter) and to act as vertical surface (tail) area. But the simultaneous inclusion of genuine vertical surfaces makes no sense. If the two vertical tails weren’t there, this feature would make sense – and it’s cribbed almost exactly from some research designs the USAF experimented with in the 1990’s. The drooped tips act as the vertical tail area and, because of their angle, deflect radar waves upward, preventing them from returning back to the radar that sent them. But here we also have twin vertical tails installed. Why both? The latter are more effective aerodynamically, but carry a “stealth” penalty. The drooped tips are better for stealth, but aren’t quite as good as tails. But having both makes no sense – you get the best of both, but also the worst of both, all with the weight penalty of carrying two sets of surfaces. It appears to me that the designer copied some features from some USAF military test aircraft (notably the McDonnell Douglas X-36: http://en.wikipedia.org/wiki/McDonnell_Douglas_X-36, and the Boeing “Bird of Prey”: http://en.wikipedia.org/wiki/Boeing_Bird_of_Prey), and then added F-35-like vertical tails, probably since that aircraft was perceived to be “newer” or “more advanced”.

Lots of other suspicious details, from the bulky/blocky “scissors” on the nose landing gear, to the lack of an actual sealing surface between the canopy frame and the cockpit rail, down to the canopy itself, which appears to be consumer-grad Plexiglas  and extremely thin at that. All in all, it’s an “aircraft” that looks realistic at first glance or to the untrained eye, but anyone who knows much of anything about aircraft design would dismiss the whole thing as a fake within seconds. The person or team who designed it seems to have some modest experience with R/C models, but absolutely none with “real”, manned aircraft, let alone any experience at all designing modern combat aircraft.

Thanks to Aviation Expert Marc McNoghton

His google pus profile: https://plus.google.com/u/0/103383896294318249977/posts

iran

Posted on February 5, 2013, in Uncategorized. Bookmark the permalink. Leave a comment.

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