investigating Fuel pump sounds missing

[Falconeer]

When "Main Power" switch is turned on and "Engine Feed'' switch in "Norm", you should hear the fuel pumps spinning. This is quite a noise, coming from the back/center of the aircraft and can easily be heard from within the cockpit and exterior

Edited February 12, 2022 by Falconeer

[Sacarino111]

21 minutes ago, Falconeer said:

When "Main Power" switch is turned on and "Master Fuel'' switch in "Norm", you should hear the fuel pumps spinning. This is quite a noise, coming from the back/center of the aircraft and can easily be heard from within the cockpit and exterior

HI.

Interesting point.!

Saludos.Saca111

[BIGNEWY]

Hi, 

if you have any real world examples or evidence of this I can show the team please attach them.

thanks

[Falconeer]

31 minutes ago, BIGNEWY said:

Hi, 

if you have any real world examples or evidence of this I can show the team please attach them.

thanks

 

First seconds of the video, before JSF start 

 

 

 

Edited February 12, 2022 by Falconeer

[fagulha]

@FalconeerThe fuel pumps sound you´re referring to is present, i can hear it probably not so audible like in the videos (in DCS options i have "hear like in helmet" unticked, so, louder sounds inside cockpit in my case).

Edited February 12, 2022 by fagulha

[Dee-Jay]

What you hear in the videos are not the fuel pumps.

[Frederf]

DC to AC electrical converters? I assume engine ignitors need high voltage AC for spark.

[Bouli306]

2 hours ago, Frederf said:

DC to AC electrical converters? I assume engine ignitors need high voltage AC for spark.

The ignition comes from the engine alternator/generator so this is not done by the converters. But those do make noise, also the gyro of the stby AI makes sound as wel as the altimeter (internally a small hamer is 'tapping'  on the bellow of the altimeter just like you would do on a barometer). The fuel pumps only run when main power is on the jet, so they will not run unless external power is applied or after the Main Gen is online.. 

[BIGNEWY]

I will check with our SME's but I dont think there is any issue here. 

[Dee-Jay]

What we hear in the video before JFS is the altimeter vibrator.

[Falconeer]

On 2/14/2022 at 2:05 AM, Dee-Jay said:

What you hear in the videos are not the fuel pumps.

Those sounds are indeed missing, i can't find any videos with these sounds, but its very load. 

I noticed this during my work on a Viper, while running tests inside the cockpit.

And thought, hey, i dont hear this sound in DCS

On 2/14/2022 at 10:36 AM, Bouli306 said:

The fuel pumps only run when main power is on the jet, so they will not run unless external power is applied or after the Main Gen is online.. 

Ah, this might explain it...  with rampstart we don't use external power and therefore the pumps dont run 

 

Edited February 15, 2022 by Falconeer