Ask anything Thread (Air Force)

[The Observer]

As i said, internal wing structure decides where your pylons under the wing will be, not necessarily the wingtips.
J-10 has a delta wing. This, in addition to the relative behaviour of leading and trailing wing section design, to a certain limit negates the wingtip effects that you see in conventional sweeped trailing edge wings like Su27. Gripen, for example still uses wingtip pylons to decrease the drag further( saab designers are crazy for efficiency), which allows it effectively supercruise under certain loads.
In commercial jets, wingtip vortices are countered with wing fins.

Depends on how much your wing drag profile is weighted by the vortices.



Any design characterisitcs has pros/cons.
Western jets like F15 have no wingtip pylons due to designers feeling it will add too much stability and inertia and effect its performance in a A-A scenario. It all depends on what performance characteristics you're trying to squeeze out of the airframe.

So in essence, vortices increase maneuverability by destabilizing the plane but also increases drag, so some designers that wanted more efficiency might want to suppress the vortices generation and those that wanted maneuverability vice versa? did I get the reasoning correct?

p.s. super off-topic, but do you know what is PLAAF FOD tolerance standard? Is it closer to NATO (smooth runway and little to no FOD) or Soviet standard (basic runway and FOD tolerant)?

 

[stannislas]

Does anyone know how designers decide a plane's pylon arrangement, especially fighter jets?

I noticed that starting around 3-4th gen, many fighters start having pylons on wingtips. However, there are some exceptions, most notably the F-14 & F-15, Mig-29 and its descendants, and J-10. The rest all seem to have some sort of pylon/pod on wingtips, so I'm curious about what does the planes that have wingtip pylon/pods trade in exchange for more store locations.

So in essence, vortices increase maneuverability by destabilizing the plane but also increases drag, so some designers that wanted more efficiency might want to suppress the vortices generation and those that wanted maneuverability vice versa? did I get the reasoning correct?

p.s. super off-topic, but do you know what is PLAAF FOD tolerance standard? Is it closer to NATO (smooth runway and little to no FOD) or Soviet standard (basic runway and FOD tolerant)?

Well, some people regard j-10 as some level of a more higher speed oriented F-16, so think about that.

Also, base on how their landing gears and intakes were designed for all those jets, my guess is more NATO then Soviet in FOD standard

 

[Breadbox]

Does anyone have a handle on the PLAAF's ground attack methods? It seems to skew very disproportionately towards air interception, I've quite literally never seen any image or video of even the supposed multi-role J-16, SU-30Mkk or Su-35 carry/use ground attack munitions such as AGM, ASM, LGB or Glide bombs.
Every single 'ground attack' I've witnessed are unguided rocket pods, the capability of which I SEVERELY doubt in the modern combat environment. What exactly is the strategy here? Are air to ground missions relegated to UAVs and Attack helicopter or what?

It genuinely frustrates me to no end that I've not been able to find any concrete info on the matter even in Chinese sources.

 

[halflife3]

Why do fighter jets use low bypass turbofans while commercial jets and subsonic bombers use high bypass turbofans?

 

[xyqq]

Why do fighter jets use low bypass turbofans while commercial jets and subsonic bombers use high bypass turbofans?

Many fighters go supersonic, and jet engine exhaust velocity must exceed the airspeed to generate thrust. The airflow in the fan duct (i.e., bypass) is subsonic, and it yields no thrust but drag at a supersonic speed.

 

[Boku]

Anyone seen or heard of the infamous downtown Beijing skyscraper helicopter chase between escaping criminals in a private single blade helicopter and PLAAF pilots flying a twin blade helicopter?


It's full on how dangerous this helicopter chase is, the escaping criminals fly at high speed dodging high-rise buildings and the PLAAF helicopter try to follow weaving inbetween skyscrapers.


The escaping criminals often chain a child at the ankle with a 30-40 metre rope connected to the door of the single blade helicopter. The poor unfortunate child gets dragged through the air


Which leads to my original question



Imagine if you were the child in that situation, a 30 metre rope was chained on to your ankle at one end and at the other end it was tied to a helicopter and in order to prevent yourself from being dragged into the air when the helicopter took off you had 30 seconds to tie the rope to a steel pole using a traditional scouts knot that would hold strong enough to stop yourself being dragged into the air and snap the rope? What type of knot would you have to do?



A kid really did this back in the early nineties. Pretty brave yeah

 

[daifo]

I often see western planes in possible "advertisement" shots with large loads of missles, like 8+. Is this usual for combat patrol or just literally an advertisement shot? I always just see PLAAF/N planes with 2 or 4 and rarely even 6 in the various photos/videos.

 

[banjex]

I often see western planes in possible "advertisement" shots with large loads of missles, like 8+. Is this usual for combat patrol or just literally an advertisement shot? I always just see PLAAF/N planes with 2 or 4 and rarely even 6 in the various photos/videos.

Yeah, iirc I've seen Russian firms do that as well. But it's exaggerated. Realistically, fighters generally carry much fewer missiles than depicted in marketing materials. In Syria, for example, Russian Flankers were carrying two air to surface missiles and two short range air to air missiles. Even though the jets have 8-12 pilons.

 

[Deino]

Me again with a maybe stupid question. I'm just doing a bit reserach on the recent Sino-Indian conflict and the Orbat of both forces in that region as such I was looking / searching some more background. I'm now a bit surprised that esp. recent Indian media outlets often mention the PLAAF is limited since it has only "five main airfields in Tibet (Kongka Dzong, Hoping, Pangta, Linzhi and Gargunsa) and another two in Xinjiang (Hotan and Kashgar)".

My problem now is that several of them are completely unknown to me...

Please, Log in or Register to view URLs content!

Do you know more or have an idea, which bases or airports they are referring to?

 

[Bhurki]

Me again with a maybe stupid question. I'm just doing a bit reserach on the recent Sino-Indian conflict and the Orbat of both forces in that region as such I was looking / searching some more background. I'm now a bit surprised that esp. recent Indian media outlets often mention the PLAAF is limited since it has only "five main airfields in Tibet (Kongka Dzong, Hoping, Pangta, Linzhi and Gargunsa) and another two in Xinjiang (Hotan and Kashgar)".

My problem now is that several of them are completely unknown to me...

Please, Log in or Register to view URLs content!

Do you know more or have an idea, which bases or airports they are referring to?

View attachment 62381

The upper map shows all currently usable airfields along the border.
The lower map, is correct if going by claimed areas, however, is wrong if going by controlled area. The eastern orange part is entirely under Indian control.

The limitation vis-a-vis the mentioned airfields is not about their quantity, but the fact that they are at a considerably high altitude, almost all over 10,000ft. This reduces the combat load an aircraft would be able to carry.
However, this fact has been beaten to death by the Indian side while citing operational disadvantages to plaaf, while totally ignoring the fact that adding 25-30% of the length of the runway(entirely possible due to favourable terrain) will completely counteract the problem( except probably for tire wear due to higher landing, takeoff speeds)