Question regarding Citation C525?
Thread Starter
Joined: Mar 2005
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From: UK
Question regarding Citation C525?
Can anyone tell me what the black paddle is for that sits behind the engine exhaust?
At first, I thought it was just to protect the engine pylon from the hot exhaust gasses, but the other day I saw one of these aircraft taxiing and it was actually moving to deflect the exhaust flow. Considering that this aircraft does not have reverse thrust, what is it's function?
Image courtesy of !!!!!!!!!!!!!!
At first, I thought it was just to protect the engine pylon from the hot exhaust gasses, but the other day I saw one of these aircraft taxiing and it was actually moving to deflect the exhaust flow. Considering that this aircraft does not have reverse thrust, what is it's function?
Image courtesy of !!!!!!!!!!!!!!
Thread Starter
Joined: Mar 2005
Posts: 553
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From: UK
Exactly as you stated, a paddle; giving it greater forward speed to keep up with the grown up planes.
They don't produce any forward thrust, they just reduce the amount of reward thrust at idle. For use whilst taxying.
Last edited by TotalBeginner; 10th June 2008 at 18:40.
Joined: Feb 2005
Posts: 366
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From: California
TB
Here is a serious answer, honest.
They are called thrust attenuators and are moved into the exhaust to deflect the thrust at idle (tickover), this reduces forward thrust while you are trying to slow down. Idle rpm's are fairly high and there is quite a lot of residual thrust.
The CJ3 does not have them as the engines are FADEC controlled and idle at a lower rpm, therefore less residual thrust.
They are operated by levers on the throttle quadrant, and are not interconnected to N1 values.
Cheers,
f
Here is a serious answer, honest.
They are called thrust attenuators and are moved into the exhaust to deflect the thrust at idle (tickover), this reduces forward thrust while you are trying to slow down. Idle rpm's are fairly high and there is quite a lot of residual thrust.
The CJ3 does not have them as the engines are FADEC controlled and idle at a lower rpm, therefore less residual thrust.
They are operated by levers on the throttle quadrant, and are not interconnected to N1 values.
Cheers,
f
Joined: Mar 2004
Posts: 2,451
Likes: 6
From: schermoney and left front seat
They are deflected with WOW and throttles idle. Unless you use the emer stow switch.
Having them stowed gives you a 5% penalty in T/O distance. No penalty in LDG dist if I remember correctly. Mounted on CJ, CJ1 and CJ2. All the pluses and the 3 donīt have em as they have FADEC with lower idle.
Operated hydraulically. On a side note, there is a difference on how they deploy during startup, I think on the 2 both move, on the CJ and the 1 they move when the respetive engine is started.
Having them stowed gives you a 5% penalty in T/O distance. No penalty in LDG dist if I remember correctly. Mounted on CJ, CJ1 and CJ2. All the pluses and the 3 donīt have em as they have FADEC with lower idle.
Operated hydraulically. On a side note, there is a difference on how they deploy during startup, I think on the 2 both move, on the CJ and the 1 they move when the respetive engine is started.
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Strictly speaking,
In an admittedly Pedantic fashion, they don't "Attenuate" (Reduce) thrust so much as "Vector" it away from rearward, and in directing thrust "To the Side" reduce forward motion. They are "Poor Mans" Reversers.
Airfoil
(Nice Photo)
Airfoil
(Nice Photo)
