General Dynamics F-16 Fighting Falcon

[Dave S.]

Belly shot

[Chris V]

[Joe Copalman]

[Daniel DeSart]

[Chris Kennedy]

I have a question for one of you F-16 experts. What is that sound that they make just before touching down? I would describe it as kind of a high pitched "wheep."

[jslugman]

Valve that regulates the bleed air operating the burner can (turkey feathers).

[Dave S.]

Adding a little more detail to James' comment.  I spoke with a ex-F-16 driver a while back regarding this same sound.  It's caused when adjustments are made to the engine's exhaust nozzle (i.e. turkey feathers).  The Pratt & Whitney powered F-16's use an air-motor driving a mechanical linkage to regulate the nozzle position.  High pressure compressor discharge air is used to drive the air-motor.

From a thread on the F-16.net forum I found this entry by 'That_Engine_Guy' which pretty much agrees with what that ex-F-16 driver told me, but with a bit more detail.

".. the .. noise you hear when Viper (or Eagle) flies overhead is exhaust air from the CENC (Convergent Exhaust Nozzle Control) on the engine. It is an air motor that moves the nozzle through mechanical (Jack-screw) actuators. (Kinda like a high speed air ratchet) Now you know it is a Pratt before you can see it!

The Nozzle positions to maintain Fan (N1) RPM and EPR (Engine Pressure Ratio) as the engine runs but also has to contend with pressures/feedback from the engine's control system. This is why it varies so much during most operation. MIL is where the nozzle is most steady at closed. At MAX the nozzle is almost 100% open but continually adjusts as flow through the engine varies. Inlet Temperature, air pressure, humidity, etc all affect the performance of the Fan/Compressor and combustion. The nozzle will constantly adjust to keep Fan RPM, Stall Margin, and pressures within normal limits."

[Chris Kennedy]

Thanks, James and Dave. I understand now.

[Joe Copalman]

Whup-whup . . . Whooooop.

[Joe Copalman]

[Dave S.]

Here's another from a recent visit to Luke.  Quite pleased with how well I lined it with the centerline, considering he was taxiing at the time.



I think the pilot just had an idea, given the light bulb that just lit off on the tail.

[Daniel DeSart]

[Daniel DeSart]

[Brian Lockett]

Former 57th Wing Aggressors from Nellis AFB on approach to land on Runway 03 Right at Luke AFB today.

General Dynamics F-16C Block 42H 89-2148

General Dynamics F-16C Block 42D 88-0548

[Jeff D. Welker]