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Newbie Joined: Mar 16, 2005 Posts: 16 Status: Offline

I'm not sure if this is the right place in the forums for this.
I was playing Falcon 4.0 O.F 4.5 and I notice that in the game the nozzle position is affected by LG handle position. If the handle is up the nozzle (in the game) will stay close (5 to 0% at all throttle settings except AB) and with LG handle down it will open back to the normal 96 to 100% at idle. Now , I don't believed that to be right. I posted this on another forum and a guy there was saying that that is what it reads in the 1F-16c-1. I have look in the 1F-16CG-2-70GS-11 and 1F-16CG-2-70FI-11 I can not find anything about the landing gear handle affecting the nozzle position. To me that does not make since since the DEC/DEEC schedule the nozzle due by PLA signal and mach number of the air going through the engine, if I understand the GS correctly. OK so my question is:

--Is the nozzle position affected by the LG handle in the real jet?
--If so, does it do the same in GE and PW engine?
-- What T.O. has this info?

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Newbie Joined: Mar 31, 2008 Posts: 9 Status: Offline

Actually the Nozzle should open when the throttle is at or near idle and the landing gear is (selected) down. This is called "Idle area reset" and serves to decrease the thrust level at idle. I do not know how it is modelled in the GE F-16's but this is a fact in the PW F-16's. Also in the PW jet the nozzle should not open more than 95%.

I am an Flight sim instructor and do not know in what GS it is written. But it is in the -1, it reads: To reduce the idle thrust level, the nozzle is commanded open when the throttle is at or near idle and the LG handle is down.

Hope this helps

Elite Joined: Oct 30, 2006 Posts: 627 Status: Offline

The nozzle will close (along with LDG config warnings) on a Viper if you attempt to start her with the gear handle up. IAW 1F-16C-seen-it-happen.

Newbie Joined: Mar 16, 2005 Posts: 16 Status: Offline

VarkVet wrote:

The nozzle will close (along with LDG config warnings) on a Viper if you attempt to start her with the gear handle up. IAW 1F-16C-seen-it-happen.

I went to my support section and they said that they did not have that T.O. Very Happy

-Thanks for the response guys, any maintenance T.O. references?
-Does it get signal from WOW switches for that? I know the DEEC/DEC does get a signal from WOW switch to record engine flight time but, does it use the same signal?
-Does the DEEC/DEC receives a signal from the LG panel or somewhere else?
-Does it go through the LG matrix?
-Is there a fault tree if the nozzle stays open with LG handle up?

Elite Joined: Dec 14, 2005 Posts: 687 Status: Offline

gastonrivera78 wrote:

I was playing Falcon 4.0 O.F 4.5 and I notice that in the game the nozzle position is affected by LG handle position. If the handle is up the nozzle (in the game) will stay close (5 to 0% at all throttle settings except AB) and with LG handle down it will open back to the normal 96 to 100% at idle. Now , I don't believed that to be right. I posted this on another forum and a guy there was saying that that is what it reads in the 1F-16c-1. I have look in the 1F-16CG-2-70GS-11 and 1F-16CG-2-70FI-11 I can not find anything about the landing gear handle affecting the nozzle position. To me that does not make since since the DEC/DEEC schedule the nozzle due by PLA signal and mach number of the air going through the engine, if I understand the GS correctly. OK so my question is:

--Is the nozzle position affected by the LG handle in the real jet?
--If so, does it do the same in GE and PW engine?
-- What T.O. has this info?

Yes in the PW Vipers nozzle position is affected by the LG handle, and Yes it is officially called "Ground Idle Thrust" or GIT. PLA is used for IDLE determination and scheduling but the LG handle does activate Ground Idle in the DEEC logic like the IAR (Idle Area Reset) switch

The "Reduced Idle Thrust" switch is inoperative in the cockpit, but it is an automatic function of the PW-220 and PW-229. Reference the flight manual for a Viper with PW-229. (Even through the PW-220 section doesn't mention Ground Idle in detail, it behaves roughly the same.)

Ground idle – Provides the lowest level of idle thrust while maintaining adequate stall margin. The nozzle opens to greater than 80% Ground idle is activated with the LG handle in DN and the throttle at or near IDLE.

Flight idle – Flight idle provides in-flight idle thrust when the LG handle is in UP and the throttle is at or near IDLE. The nozzle is open to 0-20% percent and the thrust is higher than ground idle.

Regardless of temperature, NOZ POS indicator indication should not exceed 20% at MIL for a PW-229 or 30% for a PW-220.

So in flight (gear up) a PW-229 nozzle should stay between 0-20% from IDLE to MIL, and only more for AB operation.

I can find no reference for GE "Ground Idle" so I don't believe it has this feature. (Anyone confirm?)

Now the GE Nozzle should stay between 0-15% from IDLE to MIL, and only open more for AB operation.

Now for all engine types NOZ POS should only "approach" 100%. Typically 95% and not much more. Any excursion over 100% would cause an out of limit situation that causes a fault, transfer to SEC and automatic AB cancellation and inhibit. (After 100% things in the nozzle start to bend/break...)

SEC idle thrust is much higher than PRI idle thrust for both GE and PW. The nozzle would be closed for all engine speeds. This is to provide the maximum usable thrust in an emergency situation.

In the PW-220 or PW-229 FI or GS books look for IAR or GIT, if you have a -1 w/PW-229 look for "Ground Idle." When looking at an engine control system schematic, look for the "LGH CONT ASSY (76-11) / Idle AJ Reset" circuit input to the DEEC.

If you know an experienced "engine guy or gal" ask to read their "Engine Monitoring System" reference book from P&W; it's not a T.O. but a handy reference on how the logic/systems of the PW-220 or PW-229 work in GREAT detail. (Right down to the software logic/data within the DEEC/EDU.)

Keep 'em flyin' Thumb

TEG

Newbie Joined: Mar 16, 2005 Posts: 16 Status: Offline

Cool, thanks for the response. It appears to me that this is a PW thing, maybe?
One question, you said:

Quote:

Now for all engine types NOZ POS should only "approach" 100%. Typically 95% and not much more. Any excursion over 100% would cause an out of limit situation that causes a fault, transfer to SEC and automatic AB cancellation and inhibit. (After 100% things in the nozzle start to bend/break...)

I work GE here at the Kun (80Th Juvats) and the 70JG-00-11 put the parameters at idle at 96% to 106% and normally (in the engines I have run before) is around 100% to 102% at idle. Never thought much of it since it is within parameters IAW the T.O. You are saying that is wrong? Man is amazing all you forget after working a different airframe for several years. At any rate thanks for the response guys, I appreciated.

Elite Joined: Dec 14, 2005 Posts: 687 Status: Offline

gastonrivera78 wrote:

-Thanks for the response guys, any maintenance T.O. references?

Not sure about the LGH Control Assembly or wiring, but the FI for a PW-220 or PW-229. See "Schematic Diagram- Engine Controls" drawing page 12-76-11-02. Remember "Reduced Idle Thrust" is not used.

gastonrivera78 wrote:

-Does it get signal from WOW switches for that? I know the DEEC/DEC does get a signal from WOW switch to record engine flight time but, does it use the same signal?

No; WOW is actually an EDU input used to track "IFT" or In Flight Time. The signal used for Nozzle Position feeds through the DEEC from the LGH CONT ASSY. If it were the case the nozzle would only open for GIT when there was WOW, but in fact it reacts to the LGH signal WOW or not.

gastonrivera78 wrote:

-Does the DEEC/DEC receives a signal from the LG panel or somewhere else?

From what I can see yes; the "LGH CONT ASSY"

gastonrivera78 wrote:

-Does it go through the LG matrix?

From what I gather from the schematic, No, only the LGH CONT ASSY.

gastonrivera78 wrote:

-Is there a fault tree if the nozzle stays open with LG handle up?

Not sure but there is a IAR/GIT circuit malfunction, EMS fault 4195 for the PW-229. For either PW engine the Engine Nozzle Position faults fall under system 77-00-00.

gastonrivera78 wrote:

I work GE here at the Kun (80Th Juvats) and the 70JG-00-11 put the parameters at idle at 96% to 106% and normally (in the engines I have run before) is around 100% to 102% at idle. Never thought much of it since it is within parameters IAW the T.O. You are saying that is wrong?

I'm not saying it's wrong, just going by the GE-100 in our data; it says 95% at MAX-AB, not sure about Idle? The GE must have lower tolerances for the nozzle feed-back and/or position? At NOZ POS 102% in a PW you have either a miss-rig in the NOZ POS Transmitter/CENC/Pri-Actuator, or your CENC has over-driven your actuators and possibly broken some flex-shafts... It's almost impossible to reach anything over 100% or less than 0%, the mechanical actuators of a PW will reach their stops; they can only turn so far.

Keep 'em flyin' Thumb

TEG

Newbie Joined: Mar 16, 2005 Posts: 16 Status: Offline

Cool man thanks for the response, at least now it makes since. Again thank you very much.

Quote:

I'm not saying it's wrong, just going by the GE-100 in our data; it says 95% at MAX-AB,

Our T.O. says in max AB nozzle should be 50 to 70%, and it is around that normally.

Quote:

At NOZ POS 102% in a PW you have either a miss-rig in the NOZ POS Transmitter/CENC/Pri-Actuator, or your CENC has over-driven your actuators and possibly broken some flex-shafts... It's almost impossible to reach anything over 100% or less than 0%, the mechanical actuators of a PW will reach their stops; they can only turn so far.

Not sure why it has bigger tolerances, could it be due to the fact that it is hydraulically actuated?
(For those of you that might not know, GE use engine oil to actuate nozzle through the "engine driven hydraulic pump", which is confusing name since there is a "aircraft engine driven hydraulic pump", I always mix them up.)

Anyway, you guys are a ton of help, again thank you.

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