Whistling Viper

[Alicatt]

This year we have heard a distinctive whistle from the F-16s coming in to land, not heard it in previous years and my wife has commented on hearing it to as it is unusual, anyone know what it is? these are Belgian F-16s.

 

[silverdevil]

34 minutes ago, Alicatt said:

This year we have heard a distinctive whistle from the F-16s coming in to land, not heard it in previous years and my wife has commented on hearing it to as it is unusual, anyone know what it is? these are Belgian F-16s.

 

i cannot hear a whistle in the video. i can say that i live near many airports and airbases. i often hear a whine from the engines when they are idled preparing to land. it also depends on engine type. turbine vs turbofan.

[mvsgas]

1 hour ago, Alicatt said:

This year we have heard a distinctive whistle from the F-16s coming in to land, not heard it in previous years and my wife has commented on hearing it to as it is unusual, anyone know what it is? these are Belgian F-16s.

 

This is a wild ass guess from me, but the only two things that whistle like that in an F-16AM are the EPU when activating or the nozzle of the engine. My time with A models is limited to the training aircraft that had not flown in years.

[Alicatt]

30 minutes ago, silverdevil said:

i cannot hear a whistle in the video. i can say that i live near many airports and airbases. i often hear a whine from the engines when they are idled preparing to land. it also depends on engine type. turbine vs turbofan.

Hmmm can't hear it on that either, I can hear it on the original video on my phone  grr Utube!

[silverdevil]

Just now, Alicatt said:

Hmmm can't hear it on that either, I can hear it on the original video on my phone  grr Utube!

doh. how large is original? maybe you could share another way?

[Alicatt]

25 minutes ago, mvsgas said:

This is a wild ass guess from me, but the only two things that whistle like that in an F-16AM are the EPU when activating or the nozzle of the engine. My time with A models is limited to the training aircraft that had not flown in years.

The aircraft in the video is turning base to finals, we are about 3 to 3.5 miles from the runway here.

My wife first pointed it out about a month ago and I thought it was a neighbour doing something. but I have heard it often now and always at that same point id is just a Veeep sort of like someone blowing a short note on a kazoo, we heard about 20 of them this afternoon and they all had it. 

[silverdevil]

13 minutes ago, Alicatt said:

The aircraft in the video is turning base to finals, we are about 3 to 3.5 miles from the runway here.

My wife first pointed it out about a month ago and I thought it was a neighbour doing something. but I have heard it often now and always at that same point id is just a Veeep sort of like someone blowing a short note on a kazoo, we heard about 20 of them this afternoon and they all had it. 

i would have to guess it is the engine spooling down. but dunno without really hearing it.

 

edit: found this https://www.f-16.net/forum/viewtopic.php?t=18535 and 

 

Edited August 11, 2022 by silverdevil

[=475FG= Dawger]

Probably bleed air actuator for something. Maybe the nozzle. 

[mvsgas]

19 minutes ago, Alicatt said:

The aircraft in the video is turning base to finals, we are about 3 to 3.5 miles from the runway here.

My wife first pointed it out about a month ago and I thought it was a neighbour doing something. but I have heard it often now and always at that same point id is just a Veeep sort of like someone blowing a short note on a kazoo, we heard about 20 of them this afternoon and they all had it. 

Then is very likely to be the engine nozzle. Look for Convergent Exhaust Nozzle Control (CENC) here or in google. I have posted many time about it.

[mvsgas]

20 minutes ago, silverdevil said:

 

 

LOL, some people make up some crazy theories. The guys in the video says the whistle is from a sensor when the aircraft is close to the ground...why would the aircraft have something like that on the outside? lol. I hated being on airshows next to the jet, granted only did it once in Oshkosh EAA 1999 . So many want verification on their misconceptions and did not like when you told them it did not work how they believe it did. 

[slowfinger23]

Very likely to be the Pratt and Whitney engine nozzle. Exhaust Nozzle Control (CENC).

[smire666]

Can't it be simply just the Doppler-effect

[silverdevil]

4 minutes ago, smire666 said:

Can't it be simply just the Doppler-effect

it is made by gremlins screaming on the wings because they hate to land.

[Alicatt]

2 hours ago, silverdevil said:

i would have to guess it is the engine spooling down. but dunno without really hearing it.

 

edit: found this https://www.f-16.net/forum/viewtopic.php?t=18535 and 

 

 

The second jet made the noise we hear here  it's very short in length

Edit: personally I said to my wife I thought it was bleed air, but I'll have a search for the CENC 

Thanks for all the replies.

Edited August 11, 2022 by Alicatt

[FireNLD]

Nobody? Right I'll help

 

Belgian F-16AM's use the P&W F100 engines (the early blocks until 25 all used a variant of this. Nowadays a 30/40/50 has the GE engine, early blocks till 25 and AM MLU/32/42/52 use the P&W engine). One thing that the P&W engine has, is that the nozzle actuator makes that noise when the nozzle adjusts. It's very common to hear on the birds running the P&W F100 engines, like the 15C and 15E. They even added it to the 15C - Go external view while parked and throttle up and down (its glorious)

It's not something the GE-129 has unfortunately. So not something to expect (sad actuator noises). 

 

Edited August 11, 2022 by FireNLD

[silverdevil]

24 minutes ago, Alicatt said:

The second jet made the noise we hear here  it's very short in length

Edit: personally I said to my wife I thought it was bleed air, but I'll have a search for the CENC 

Thanks for all the replies.

 

ah i did a search and better understand it. when the engine drops power, the nozzle (turkey feathers) close and it causes a whistle. sort of like doing a whistle with human lips. it is patented technology from 1961 which i assume is why not all engines have CENC.

[Alicatt]

18 hours ago, FireNLD said:

Nobody? Right I'll help

 

Belgian F-16AM's use the P&W F100 engines (the early blocks until 25 all used a variant of this. Nowadays a 30/40/50 has the GE engine, early blocks till 25 and AM MLU/32/42/52 use the P&W engine). One thing that the P&W engine has, is that the nozzle actuator makes that noise when the nozzle adjusts. It's very common to hear on the birds running the P&W F100 engines, like the 15C and 15E. They even added it to the 15C - Go external view while parked and throttle up and down (its glorious)

It's not something the GE-129 has unfortunately. So not something to expect (sad actuator noises). 

 

 

Thanks, now I have to explain this to my wife

[Lee1]

On 8/11/2022 at 5:37 PM, Alicatt said:

The aircraft in the video is turning base to finals, we are about 3 to 3.5 miles from the runway here.

My wife first pointed it out about a month ago and I thought it was a neighbour doing something. but I have heard it often now and always at that same point id is just a Veeep sort of like someone blowing a short note on a kazoo, we heard about 20 of them this afternoon and they all had it. 

Hear that often from the F15s going over my house on the way into Lakenheath. The sound you describe is very much like the actuation motors for nozzles, airbrakes etc.

Edited August 13, 2022 by Lee1