Ask anything Thread (Air Force)

[ougoah]

The flow across the radome is still more laminar than elsewhere beyond those points so positioning a few around the radome is the obvious solution when you can't put a pitot tube right at the vertex. It probably wasn't hard at all to develop alternatives to the old pitot application because all you'd need is maybe a few on either side of your radome and run lots of wind tunnel tests to develop accurate models from which you apply the algorithm that adjusts for the disturbed airflow.

Since the flow would still be much more laminar and the models produce accurate coefficients to apply to "real" readings, all engineers would need to do is run tests for different altitudes for atmospheric pressure and maybe under different turns and acceleration of gravity. Same thing for any 4th gen fighter or commercial airliner that doesn't have a pitot tube right on the tip of the nose. Difficult would be to embed the instrument so as to not have any protrusions. I think the F-35 achieved that? Not counting for prototypes that need more accurate readings.

 

[The Observer]

The flow across the radome is still more laminar than elsewhere beyond those points so positioning a few around the radome is the obvious solution when you can't put a pitot tube right at the vertex. It probably wasn't hard at all to develop alternatives to the old pitot application because all you'd need is maybe a few on either side of your radome and run lots of wind tunnel tests to develop accurate models from which you apply the algorithm that adjusts for the disturbed airflow.

Since the flow would still be much more laminar and the models produce accurate coefficients to apply to "real" readings, all engineers would need to do is run tests for different altitudes for atmospheric pressure and maybe under different turns and acceleration of gravity. Same thing for any 4th gen fighter or commercial airliner that doesn't have a pitot tube right on the tip of the nose. Difficult would be to embed the instrument so as to not have any protrusions. I think the F-35 achieved that? Not counting for prototypes that need more accurate readings.

The F-35 still have the pitot tubes, they're located just behind the radome like on F-22.

As for the no protrusion instrument that replaces pitot tube, I think it's called pitot plate and it is used on B-2 bomber.
Here's

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to a discussion about pitot plate.

 

[davidau]

I am aware that the pitot tube is to measure speed of an aircraft. Can someone please tell me why some fighter jets do not have pitot tube at the nose, why others have.
In a carrier configuration, would it not the best not to have pitot tube at the noise but somewhere under the nose for obvious reasons..
Thank you

 

[crash8pilot]

I am aware that the pitot tube is to measure speed of an aircraft. Can someone please tell me why some fighter jets do not have pitot tube at the nose, why others have.
In a carrier configuration, would it not the best not to have pitot tube at the noise but somewhere under the nose for obvious reasons..
Thank you

Answered you already:

Pitot tubes don't measure airspeed, they measure total ram air pressure - If my plane was not moving on the tarmac and a gust of wind blew 20 knots across my pitot tube, my airspeed indicator would read 20 knots. The air data computer (or airspeed indicator) subtracts static pressure (measured from a static port) from total pressure (measured at the pitot tube) to get the value of dynamic pressure, which is how we get the value of airspeed.

Since the aircraft body itself will distort airflow (especially in supersonic flight when subsonic/supersonic boundary layer forms), most fighters have a long pitot tube on the nose to allow it to pierce the boundary layer into smooth airflow in front of the body of the aircraft in order to receive accurate readings of dynamic pressure. Stealth fighters tend not to have such a feature because it'll increase its radar cross section. I'm a pilot and not an engineer, but I'm guessing plenty of research was done to place these "conventional" pitot tubes on the radome of fifth-generation stealth fighters to ensure they receive good clean airflow through all areas of the flight envelope. These "conventional" pitot tubes are also probably more expensive and sophisticated to produce, install, as well as maintain when compared to the long pitot probes most fighters, which is why I'm guessing is why they're not more widely featured across modern fighter planes.

In addition, a pitot tube will almost never be placed under the nose where airflow almost certainly will be disturbed across all areas of the flight envelope, and therefore won't give an accurate reading of total pressure and therefore airspeed.

 

[11226p]

AVIC promotional video from I think the official AVIC WeChat account,

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, has a ton of great shots

 

[Aniah]

The Air Force forum continues to be bolded even though I have read everything on the first page. Is anyone else having this issue? Kinda messes with me since I click on here thinking there is a new post but nothing...

 

[grulle]

anyone know how many fighters China has that's AESA? so J-10B/C, J-11B, J-16, and J-20. total how many jets?

 

[11226p]

anyone know how many fighters China has that's AESA? so J-10B/C, J-11B, J-16, and J-20. total how many jets?

Note those are just ballpark estimates and not accurate figures

J-16: 150+
J-20: ~30-50
J-11BG: no idea but let's estimate 50
J-10C: ~200
J-10B ~50

So in total a ballpark estimate of between 500-600+

 

[ougoah]

Note those are just ballpark estimates and not accurate figures

J-16: 150+
J-20: ~30-50
J-11BG: no idea but let's estimate 50
J-10C: ~200
J-10B ~50

So in total a ballpark estimate of between 500-600+

J-16 probably closer to 200 than 150 these days.

J-11BG probably well below 50. Probably closer to 10?

J-10B uses a PESA doesn't it?

But around 500 AESA carrying 4.5 and 5th gen fighters is the consensus with observers.

 

[11226p]

J-16 probably closer to 200 than 150 these days.

J-11BG probably well below 50. Probably closer to 10?

J-10B uses a PESA doesn't it?

But around 500 AESA carrying 4.5 and 5th gen fighters is the consensus with observers.

10 BGs is too little imo but the upgrade program has already started so I estimate they will upgrade a couple dozen air frames each year. I am never sure whether J-10B uses PESA or AESA since there were conflicting reports around its induction but the number doesn't change that much either way.