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tangoshadow
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 Posted: Jan 25, 2012 - 06:52 PM
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Enthusiast
Joined: Apr 19, 2006 - 08:13 PM
Posts: 32
Status: Offline
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Hi,
Assume you just have LAU-128 and an ALQ-131 pod, with no other stores, what effect would idle thrust have on glide distance vs. engine out? Fuel on board is 200 lbs. Assume it is flown at best glide speed.
Best regards,
TangoShadow. |
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Sponsor
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 Posted: May 20, 2013 - 10:01 AM
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F-16.net Sponsor
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JoeSambor
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Posted: Jan 26, 2012 - 12:12 PM
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Forum Veteran
Joined: Dec 28, 2004 - 05:56 AM
Posts: 751
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With 200 pounds of fuel on board, you won't have idle thrust for very long. So difference should be negligible.
Best Regards, |
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Joe Sambor
LM Aero Field Service Engineer
Woensdrecht Logistics Center, The Netherlands
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tieu
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Posted: Jan 26, 2012 - 06:19 PM
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Joined: Mar 16, 2010 - 05:31 AM
Posts: 31
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| Bigger difference between a frozen engine or windmilling than between idle and windmilling. |
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That_Engine_Guy
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Posted: Jan 27, 2012 - 02:07 AM
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Elite 2K
Joined: Dec 14, 2005 - 05:03 AM
Posts: 2198
Location: Under the engine somewhere.
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Better yet, don't run out of fuel! 
I've seen PW motors that have run for 15+ minutes without any oil pressure, but don't keep a GE inverted too long.... 
TEG |
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[Airplanes are] near perfect, all they lack is the ability to forgive.
— Richard Collins
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madrat
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Posted: Jan 27, 2012 - 04:13 AM
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Forum Veteran
Joined: Mar 03, 2010 - 03:12 AM
Posts: 986
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| I have always wondered if you would gain any sense of safety if your centerline drop tank was equipped with a smaller motor. Something that was closed off except when called for such as an emergency or to boost takeoff. Perhaps a miniature FJ44 or PW61#F turbofan, maybe even a tiny turbojet. |
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Cali
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Posted: Jan 27, 2012 - 04:53 AM
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Joined: Apr 30, 2008 - 07:52 PM
Posts: 50
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madrat wrote:
I have always wondered if you would gain any sense of safety if your centerline drop tank was equipped with a smaller motor. Something that was closed off except when called for such as an emergency or to boost takeoff. Perhaps a miniature FJ44 or PW61#F turbofan, maybe even a tiny turbojet.
No, that would be a nightmare. Why put a little motor on that when you can add something to the actual jet itself, that would be better imho, but that's still dumb I think. |
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VarkVet
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Posted: Jan 29, 2012 - 12:49 AM
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Elite 1K
Joined: Oct 30, 2006 - 04:31 AM
Posts: 1442
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I've seen PW motors that have run for 15+ minutes without any oil pressure, but don't keep a GE inverted too long....
TEG[/quote]
Whatever? Don't do this with a Pratt or the motor will stall, go into stagnation, and melt down like a candle if you don't shut it off. Shuting down the motor is the last thing I would do if I was out of control. GO GE!!!!!
http://www.youtube.com/watch?v=Rv9YC-gaNYo |
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My eyes have seen the glory of the Lord and the esthetics of the Flightline
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tangoshadow
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Posted: Jan 29, 2012 - 01:39 AM
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Joined: Apr 19, 2006 - 08:13 PM
Posts: 32
Status: Offline
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Thanks for the replies!
I thought the Thunderbirds jets were P&W but apparently they fly the Block 50 now, and limit negative g flight to 30 seconds due to oil pressure concerns?
Best regards,
TangoShadow. |
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VarkVet
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Posted: Jan 29, 2012 - 02:12 AM
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Elite 1K
Joined: Oct 30, 2006 - 04:31 AM
Posts: 1442
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tangoshadow wrote:
Thanks for the replies!
I thought the Thunderbirds jets were P&W but apparently they fly the Block 50 now, and limit negative g flight to 30 seconds due to oil pressure concerns?
Best regards,
TangoShadow.
T-Birds fly 52's with -229 Pratt, and why would you want to fly upside down for more than 30? |
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My eyes have seen the glory of the Lord and the esthetics of the Flightline
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tangoshadow
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Posted: Jan 29, 2012 - 02:27 AM
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Joined: Apr 19, 2006 - 08:13 PM
Posts: 32
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VarkVet wrote:
tangoshadow wrote:
Thanks for the replies!
I thought the Thunderbirds jets were P&W but apparently they fly the Block 50 now, and limit negative g flight to 30 seconds due to oil pressure concerns?
Best regards,
TangoShadow.
T-Birds fly 52's with -229 Pratt, and why would you want to fly upside down for more than 30?
Thanks for the correction, and it was something I heard. I can understand the pilot not wanting to!  |
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VarkVet
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Posted: Jan 29, 2012 - 03:15 AM
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Joined: Oct 30, 2006 - 04:31 AM
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tangoshadow wrote:
Thanks for the correction, and it was something I heard. I can understand the pilot not wanting to!
No worries ... 52's with Pratts do Stunts and 50's with GE's do Combat |
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My eyes have seen the glory of the Lord and the esthetics of the Flightline
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That_Engine_Guy
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Posted: Jan 29, 2012 - 03:54 AM
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Elite 2K
Joined: Dec 14, 2005 - 05:03 AM
Posts: 2198
Location: Under the engine somewhere.
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VarkVet wrote:
tangoshadow wrote:
Thanks for the correction, and it was something I heard. I can understand the pilot not wanting to!
No worries ... 52's with Pratts do Stunts and 50's with GE's do Combat
Because the GE's can't do stunts, and the Pratts can do either; they just have a handfull of them...
Even though the GE powered Vipers outnumber the Pratts 2/1, the USAF Thunderbirds still use Pratts. Why? Lack of oil starvation resistance.
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Whatever? Don't do this with a Pratt or the motor will stall, go into stagnation, and melt down like a candle if you don't shut it off. Shuting down the motor is the last thing I would do if I was out of control. GO GE!!!!!
The last time I saw someone do that with a GE, the aircraft recovered, only to leave the pilot with one seized GE F110... Too long inverted.
I've never seen a PW-220 or PW-229 NOT recover from a stall. The PW-229s almost never stall.
Lets not forget the Viper/PW-229 combination has the lowest 'Class-A Mishap Rate' for any USAF fighter! 
 TEG |
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[Airplanes are] near perfect, all they lack is the ability to forgive.
— Richard Collins
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VarkVet
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Posted: Jan 29, 2012 - 04:15 AM
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Elite 1K
Joined: Oct 30, 2006 - 04:31 AM
Posts: 1442
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| [quote="That_Engine_Guy"]
VarkVet wrote:
Lets not forget the Viper/PW-229 combination has the lowest 'Class-A Mishap Rate' for any USAF fighter!
TEG
Not enough 229's around (in F-16 land) to dabble in the Class A mishap stats? Of course it will look good? Heck, even 220's are a thing of the past. |
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My eyes have seen the glory of the Lord and the esthetics of the Flightline
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JetTest
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Posted: Jan 29, 2012 - 04:18 PM
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Senior member
Joined: Jul 04, 2007 - 01:22 AM
Posts: 417
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| Actually I am pretty sure that world-wide, 52% of all F16's are PW powered. USAF numbers are low due to congressional mandat that there be about a 50/50 engine mix and all USAF F15's are PW. Look up the stats. |
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exfltsafety
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Posted: Jan 29, 2012 - 05:12 PM
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Senior member
Joined: Aug 05, 2009 - 08:11 PM
Posts: 281
Status: Offline
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The USAF Viper/PW-229 engine-related Class A mishap rate is 0  But it also had less than 300,000 flight hours as of end of last fiscal year. See http://www.afsc.af.mil/shared/media/document/AFD-080819-035.pdf. The USAF Viper/GE-129 rate was 1 at just under 1 million flight hours.
JetTest - VarkVet was talking about just the PW-229, not the total PW-powered F-16 fleet. |
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