Qaher 313 New Iranian Fighter Jet

[simplex]

Is it normal that the pilot moving in the cockpit could cause the aircraft to visibly rock from side to side?!

No way!

A pilot moving continuously its body with 1 m/s would have a momentum 8333 times smaller than that of the Q-313 which means that the perturbation introduced by the pilot is insignificant.

Demonstration
Supposing the plane has a mass of 4000 kg and travels at 600 km/h and the pilot weights 80 kg and rocks there in the cockpit at 1 m/s then:

P_plane = m_plane * V_plane = 4000 kg * 166 m/s (600 km/h) = 666666 kg*m/s

P_pilot = m_pilot * V_pilot = 80 kg * 1 m/s = 80 kg*m/s

P_plane / P_pilot = 8333

 

[RobWilliams]

Exactly, if the plane SHOULDN'T move, then I have serious doubts (not that they didn't exist before) about that thing because it DOES move. Seems like a cheap thing with just frame built up with plastic panels with nothing actually inside of her that would actually facilitate lift - like a big heavy engine for example.

I'm calling shenanigans on this one, don't believe it one bit.

Side note: No need to explain the basic solid mechanics of what is going on, i'm well aware of the mathematics because of what I spend most of my time doing all week.

Which coindicentally are irrelevant, I'm talking about when the plane is on the ground, he's fidgiting and you can clearly see the airframe moving around because of it. I'm not talking about in flight as i've no idea about it's performance (pffft) and I wouldn't be posting any sort of numbers if you don't either.

 

[StobieWan]

No way!

A pilot moving continuously its body with 1 m/s would have a momentum 8333 times smaller than that of the Q-313 which means that the perturbation introduced by the pilot is insignificant.

Demonstration
Supposing the plane has a mass of 4000 kg and travels at 600 km/h and the pilot weights 80 kg and rocks there in the cockpit at 1 m/s then:

P_plane = m_plane * V_plane = 4000 kg * 166 m/s (600 km/h) = 666666 kg*m/s

P_pilot = m_pilot * V_pilot = 80 kg * 1 m/s = 80 kg*m/s

P_plane / P_pilot = 8333

So, why is it that the aircraft rocks visibly from side to side when the pilot climbs inside it in the video ? I'm just asking because it seems very pronounced for something that should weigh several tons ?

 

[simplex]

What do you mean "this is not your own remark" ? I'm pretty sure it is my own remark, as I distinctly recall being there when it was typed....
...
I'm sorry - the alleged demo flight footage looks like poor quality footage of a scale model being flown. That's my opinion, nothing more.

In the article:

"Iran unveils new indigenous stealth fighter “Qaher 313″. And here’s a detailed analysis. February 2, 2013" (can be found using Google)

which appeared before your remark, the author states, I quote:

"Even if it is not the first flight of the aircraft as some of The Aviationist readers say, the way the depicted plane flies is suspect. It seems a radio-controlled scale model more than a modern fighter jet.

Furthermore, as someone pointed out: if the Qaher 313 actually flew, most probably Tehran would release footage of its takeoff and landing."

Honestly, the video does not seem to show a model aircraft. There is nothing in it that would point to a small scale radio controlled plane flying in the sky.

If the video shows indeed a model aircraft then the people who clime this have to come with a justification, some evidence.

 

[StobieWan]

I hadn't read the article and wasn't quoting it, which I humbly submit, would explain why I didn't cite it.

 

[RobWilliams]

In the article:

"Iran unveils new indigenous stealth fighter “Qaher 313″. And here’s a detailed analysis. February 2, 2013" (can be found using Google)

which appeared before your remark, the author states, I quote:

"Even if it is not the first flight of the aircraft as some of The Aviationist readers say, the way the depicted plane flies is suspect. It seems a radio-controlled scale model more than a modern fighter jet.

Furthermore, as someone pointed out: if the Qaher 313 actually flew, most probably Tehran would release footage of its takeoff and landing."

Honestly, the video does not seem to show a model aircraft. There is nothing in it that would point to a small scale radio controlled plane flying in the sky.

If the video shows indeed a model aircraft then the people who clime this have to come with a justification, some evidence.

Oh my god, you can't be serious?

So one article states an opinion, an opinion that a fair few people probably had who didn't even know about the articles existance, should reference that article?

Well, looks like everyone - before stating an opinion - needs to google that opinion, arrange the opinions chronologically and select the earliest reference. . .. I think not.

EDIT: I'm also going to add this video of an RC F-16 1:4 scale, watch the videos of it flying. If you reduced the quality of both the video and the audio then that'd look pretty real wouldn't it.

[nomedia="http://www.youtube.com/watch?v=qQ9dSrrBN28"]RC turbine jet F-16 scale 1:4 - YouTube[/nomedia]

EDIT: #2 Again I state observsations several people have made, the motion of the pilot - pretty small ones at that - on the ground causes the airframe to visually move suggesting that the aircraft is INCREDIBLY light. How would you account for this?

 

[simplex]

" there's no sign of a weapons bay (or room for one)"

Also F-117 has no visible sign of weapons bay and it has such a facility.

There is no room for weapons in the case of Q-313?! How do you know this?
Judging from the size of the pilot in comparison with the size of the plane is self evident that at least two rockets the size of a man can be mounted inside the plane in a weapon bay.

If you look at a Mig-15, the cockpit seems much further off the ground than the 313 and smaller in comparison to the 313.

The air intake for MiG-15 is under the cockpit. This is the reason the pilot is placed higher from the ground than in the case of Q-313 where air intakes are situated left and right from the cockpit.

 

[simplex]

So, why is it that the aircraft rocks visibly from side to side when the pilot climbs inside it in the video ? I'm just asking because it seems very pronounced for something that should weigh several tons ?

If the aircraft is stopped its momentum is 0 (zero), its speed is zero, while the momentum of the pilot is 80 kg * m/s, supposing he moves at 1 m/s. The pilot communicates a part of its momentum to the plane which makes Q-313 to move with an average speed of 2 cm/s, quite visible.

If the plane moves with 600 km/h the same pilot moving at 1 m/s induces in the plane a parasitic average speed of 2 cm/s, same as before!

If you add 2 cm/s, lateral drift, with 166 m/s, the speed of the plane, you will get a vector that differ from the unperturbed speed of the plane in an insignificant way, the new speed of the aircraft being 166.0000012 m/s.

 

[henaselakesan]

The F-5 at least is a real aircraft that flies. This thing I think, is made out of wood. Have a close look at the "air intakes". They are rough, un-smooth finishes, as if they've been sawn by hand...

Have a look here:

I laughed,I do not see any way to the plane, the F- 5,Americans are afraid of Iran's progress,Americans know do not where the future of the Persian Gulf.The aircraft killer of carriers will become.We reason that the aircraft must remain unknown to you Films did not show it off .do not tell name Engines and radar to anyone

 

[StobieWan]

Also F-117 has no visible sign of weapons bay and it has such a facility.

There is no room for weapons in the case of Q-313?! How do you know this?
Judging from the size of the pilot in comparison with the size of the plane is self evident that at least two rockets the size of a man can be mounted inside the plane in a weapon bay.


The air intake for MiG-15 is under the cockpit. This is the reason the pilot is placed higher from the ground than in the case of Q-313 where air intakes are situated left and right from the cockpit.

All of what you say is perfectly true if the aircraft F313 doesn't actually have an engine or fuel tanks. Which, judging by the way it bobs around like a toy made out of plywood and fibreglass, it probably doesn't.

While we're talking about the F117, have a look at the size of the inlets on that aircraft and then have a look at the 313 - scaled across, the 313 has what looks like a quarter the area of the F117 - how's the engine get enough air ? Same for the Mig-15 - heffing great tunnel at the front to shovel air in, and the 313 appears to have less space than I see devoted to an oil cooler on a decent sports car.

Have a look at the 313 again - it's very low and short, has intakes behind the cockpit, meaning that any engine has to be directly behind and in line with the cockpit - I'm not seeing that as leaving a lot of room for a weapon bay, particularly as the wings are quite thin and short, leaving no room for wing tanks.

Have a look at the cockpit detail in the video - the surround for the cockpit, in white, is incredibly rough, like unfinished fibre glass, the whole thing lurches around when the pilot moves in it, the canards definitely don't move (have a look at the vid again, I did...) It's a prop.

 

[SpudmanWP]

The plane is real. It is not a mock-up.

Take a look at the hi-res version of the cockpit photo attached.

1. Thin fiberglass walls with ribs exposed

2. Bare fiberglass matting visible behind the seat (painted white)

3. Total lack on any markings on the console.

4. Buttons on the center console that go all the way to the ground. Do you seriously think a pilot is going to reach his feet when he is strapped into a seat? You can barely reach your knees when in a multi-point harness.

5. Look at the shot of the pilot when he is seated. His knees are too far away from the console. This means that when seated, he cannot reach most of the controls on the console in front of him, especially the upper ones.

View attachment 5773

View attachment 5772

 

[StobieWan]

If the aircraft is stopped its momentum is 0 (zero), its speed is zero, while the momentum of the pilot is 80 kg * m/s, supposing he moves at 1 m/s. The pilot communicates a part of its momentum to the plane which makes Q-313 to move with an average speed of 2 cm/s, quite visible.

If the plane moves with 600 km/h the same pilot moving at 1 m/s induces in the plane a parasitic average speed of 2 cm/s, same as before!

If you add 2 cm/s, lateral drift, with 166 m/s, the speed of the plane, you will get a vector that differ from the unperturbed speed of the plane in an insignificant way, the new speed of the aircraft being 166.0000012 m/s.

Uh...so, why is it that no other flying aircraft behaves like that ? I've been in the back of a Harrier T4 and that didn't go anywhere when I moved around in the cockpit - and I weigh a couple of Kg more than that

My *car* doesn't bob around like that when I get in and out of it...

 

[simplex]

Again I state observsations several people have made, the motion of the pilot - pretty small ones at that - on the ground causes the airframe to visually move suggesting that the aircraft is INCREDIBLY light. How would you account for this?

A good plane is not heavy by itself (airframe + engine + electronics + wheels, etc.).
It is quite easy to make a light plane more stable by adding more fuel and weapons (payload).
Also, judging from this video:
Iran unveils new domestically built fighter jet - video | World news | guardian.co.uk
Q-313 does not seem to shake exaggeratedly for a plane of its size. I do not see anything unusual.

 

[StobieWan]

Take a look at the hi-res version of the cockpit photo attached.

1. Thin fiberglass walls with ribs exposed

2. Bare fiberglass matting visible behind the seat (painted white)

3. Total lack on any markings on the console.

4. Buttons on the center console that go all the way to the ground. Do you seriously think a pilot is going to reach his feet when he is strapped into a seat? You can barely reach your knees when in a multi-point harness.

5. Look at the shot of the pilot when he is seated. His knees are too far away from the console. This means that when seated, he cannot reach most of the controls on the console in front of him, especially the upper ones.

View attachment 5773

View attachment 5772

No combining glass for a HUD either. Or a throttle that I can see ? Unless it's hidden behind the fibreglass nearest us but it looks like the seat is right up against that side of the aircraft for some odd reason. Gerry Anderson was better at this stuff...

 

[simplex]

While we're talking about the F117, have a look at the size of the inlets on that aircraft and then have a look at the 313 - scaled across, the 313 has what looks like a quarter the area of the F117 - how's the engine get enough air ?

F-117 is a much larger plane belonging to a different size class.
This Iranian Qaher F-313 does not seem to weigh more than 4000 - 5000 kg fully loaded while F-117 weights 23,800 kg. Also F-117 is visible less aerodynamic than F-313 which means it needed powerful engines.
There is nothing wrong with Qaher F-313 from the point of view of air intakes.

 

[RobWilliams]

If you really think that level of detail and assumption of real world solid mechanics & conservation of momentum is accurate, then i'm not even going to bother explaining why it isn't. It'd be like trying to use basic algebra to solve questions involving Fourier transforms.

Exactly, a plane is heavy because it has those components in it. If - as you claim - it's a proper aircraft it would have all those components inside and therefore be HEAVY. It certainly shouldn't exhibit the sort of characteristics like jigging around when the pilot fiddles with a strap, something which - to me - would point to an inherently light aircraft on the whole.

Should note, what basis do you make the assumption that aircraft weighs 4000kg earlier? A Hawk trainer weighs something like 4,500kg empty.

EDIT: 4-5000kg fully loaded?! Ok, flat out challenge, I need to see accurate & reliable numbers for that, now.

Just going to add this in, Pucara turboprop is closer to 7000kg fully loaded.

 

[StobieWan]

F-117 is a much larger plane belonging to a different size class.

So, if it's much smaller than an F117, where's the weapons bay ? We're back to where we were a page back, except you're now agreeing with me that this thing is quite small and I guess that means we're now on the same page with me stating there's no room for an internal weapons bay, plus fuel or an engine ?

And did you really just use force and momentum equations to suggest that an adult male walking at 1 m/s into a four ton jet would push the whole thing sideways by 2cm ?

 

[simplex]

Take a look at the hi-res version of the cockpit photo attached.

1. Thin fiberglass walls with ribs exposed
...
4. Buttons on the center console that go all the way to the ground. Do you seriously think a pilot is going to reach his feet when he is strapped into a seat? ...

5. Look at the shot of the pilot when he is seated. His knees are too far away from the console. This means that when seated, he cannot reach most of the controls on the console in front of him, especially the upper ones.

1. As long as the plane is not supersonic its body can be made of fiberglass, carbon fiber and other composite materials. I do not believe Q-313 is intended for cruise speeds above 750 km/h (at sea level) so thermal stress is not significant.

4. The sit is rather low so the pilot can touch the buttons that go close to the floor.

5. Most of the controls are in the lower part of the cockpit so they can be reached by hand easily.

Also, the good resolution of the pictures shows that Q-313 is genuine. No matter how much you try to make mock-ups it will be impossible to build a credible aircraft.
If the plane had not been real Iranians would have come with some low resolution photos. On the other side they are not known to bluff.

 

[RobWilliams]

and points 2 & 3 of Spuds post you decided to avoid answering?

So you believe this aircraft to be subsonic only then? Please point me to something which explains this.

Also point me to something that supports your claim that a fully loaded one of these will be between 4 - 5000kg.

 

[simplex]

2. Bare fiberglass matting visible behind the seat (painted white)

3. Total lack on any markings on the console.

2. Even they polish that surface to make it more appealing this will not influence in any way the characteristics of the plane.

3. There are markings. On the other side, how many markings do you have on your iPad?