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PostPosted: 15 Dec 2017, 08:57 
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rynopot wrote:
I was corrected a few years ago, so let me help you.

It's not a fuel dump. [-X

It's a fuel VENT. A dump is a purposeful act by the pilot, in Gripen's case it is an automated part of design.


Pardon hijacking the tread a bit here, but I was explained by one of the ground crew why we saw this fuel vent but I still have two questions. Why do I never see a vent like that in other Gripen display videos (or am I going blind?). And the other one is that at the top part of the inverted loop where Goosen lights the burner to ignite the fuel and air mixture, is that not a dump as I remember two "batches" of vented or dumped fuel before the desired effect (flames) was achieved?

Again sorry for going off topic! :roll:

MAMBA

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PostPosted: 15 Dec 2017, 12:36 
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mamba wrote:
rynopot wrote:
I was corrected a few years ago, so let me help you.

It's not a fuel dump. [-X

It's a fuel VENT. A dump is a purposeful act by the pilot, in Gripen's case it is an automated part of design.


1. Why do I never see a vent like that in other Gripen display videos (or am I going blind?).
2. And the other one is that at the top part of the inverted loop where Goosen [Geoffrey Cooper] lights the burner to ignite the fuel and air mixture, is that not a dump as I remember two "batches" of vented or dumped fuel before the desired effect (flames) was achieved?
MAMBA


1. I have a two fold answer for you - not many people shooting Gripen displays will show that top part of the loop to you, for various reasons: e.g. damn difficult to get your neck all the way behind the camera. Secondly: The older the Jets get, the more they vent.
2. Let me see if I can find out.


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PostPosted: 15 Dec 2017, 13:08 
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As rynopot said, the Gripen pilot is just lighting up vented fuel.

Reason you don't normally see so much vented fuel streaming from the aircraft is that, in this case, the pilot forces a maneuver to allow maximum venting. The afterburner then ignites the vented fuel.

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PostPosted: 15 Dec 2017, 14:33 
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Thanks Dean and Rynopot. Just a correction, I was mainly refering to the vent after the inverted pass in front of the crowd - I have never seen that vent before. I know why it is caused but not why this is the first time I am seeing it hence my blindness question :lol: .

And big apologies for getting the pilot's name wrong! Not sure where Goosen replaced Cooper in my mind... #-o

MAMBA

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PostPosted: 15 Dec 2017, 15:39 
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mamba wrote:
rynopot wrote:
I was corrected a few years ago, so let me help you.

It's not a fuel dump. [-X

It's a fuel VENT. A dump is a purposeful act by the pilot, in Gripen's case it is an automated part of design.


Pardon hijacking the tread a bit here, but I was explained by one of the ground crew why we saw this fuel vent but I still have two questions. Why do I never see a vent like that in other Gripen display videos (or am I going blind?). And the other one is that at the top part of the inverted loop where Goosen lights the burner to ignite the fuel and air mixture, is that not a dump as I remember two "batches" of vented or dumped fuel before the desired effect (flames) was achieved?

Again sorry for going off topic! :roll:

MAMBA


Hi MAMBA

here is a neat explanation on this youtube video..

https://www.youtube.com/watch?v=3YXkzGM58XM

Quote:
Each tank is vented (or pressurised) to allow air into the tank to take the place of burned fuel, otherwise, the tank would be in negative pressure, resulting in engine fuel starvation. A vent also allows for changes in atmospheric pressure and temperature.


It is fairly common to see jets venting fuel at airshows, but it only happens for a split second or so.


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PostPosted: 15 Dec 2017, 21:01 
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Location: Centurion, Pretoria, SA
Have witnessed Gripens at RIAT vent. :D


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PostPosted: 16 Dec 2017, 07:54 
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The Hercules gave a nice but muted display by Dakota standards!

The afternoon display saw her take-off and land without performing her routine. Not sure if there was a problem.

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PostPosted: 18 Dec 2017, 07:14 
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Mango and Silver Falcons

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PostPosted: 04 Jan 2018, 08:03 
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My videos of the Airshow.

FIGHTERS:










PROPS:









SILVER FALCONS:





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PostPosted: 04 Jan 2018, 08:58 
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:smt023

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