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dongirod
Joined: 11 Dec 2006
Posts: 140
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 Posted: Wed Oct 29, 2008 3:24 pm Post subject: Recip vs. turbine |
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[quote]
"While there may be a certain amount of ego associated with transitioning to Turbines, "
I concede the fuel efficiency to props, be they recip or turbo, but if I am ever in a life threating emergency, give me a high bypass turbojet. They just hang together and produce power, lots and lots of power, push it to the stops and keep it there, it may redline and need changed on the ground but it will get you back to the hanger for the engine change. Seems like I remember being told something like, 'the last 10% of the throttle movement produces 90% of the power', do know, in reverse the difference between 80% and 90% is very amazing on a snow covered short runway, about a thousand feet on a DC-9, at max gross.
I have a friend who was on an A-300 with GE engines when they encountered a very severe emergency, involving a 45 degree pitch-up on a go around, airspeed dropped well below 100 knots. The engines were firewalled and all indicator were pegged beyond the red line. Needless to say they survived, but computer readout showed the engines produced almost 100,000 lbs thrust, double the rating. Don't know why the fuel controls let them get this high, maybe the low airspeed, not sure. The engines were borascoped and not even changed. Try that with a recip engine!
Personally, I'm glad I was not on the flight, but I have several thousand hours in turbines and have never lost an engine or had an emergency, a few minor problems yes, but never an emergency, more than I can say with recips. A certain Turbo compounded R-3350 comes to mind.
I baby my engines as I pay the bills, but also because I am on board, but I have always felt, turbines especially turbojets will take much more abuse, and like the old Timex commercial, 'it keeps on ticking'.
Don
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nico(at)cybersuperstore.c
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| Posted: Wed Oct 29, 2008 3:54 pm Post subject: Recip vs. turbine |
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Exactly my sentiments. It's just a shaft with blades on it.
From: owner-commander-list-server(at)matronics.com [mailto:owner-commander-list-server(at)matronics.com] On Behalf Of Don
Sent: Wednesday, October 29, 2008 4:21 PM
To: commander-list(at)matronics.com
Subject: Recip vs. turbine
[quote]
"While there may be a certain amount of ego associated with transitioning to Turbines, "
I concede the fuel efficiency to props, be they recip or turbo, but if I am ever in a life threating emergency, give me a high bypass turbojet. They just hang together and produce power, lots and lots of power, push it to the stops and keep it there, it may redline and need changed on the ground but it will get you back to the hanger for the engine change. Seems like I remember being told something like, 'the last 10% of the throttle movement produces 90% of the power', do know, in reverse the difference between 80% and 90% is very amazing on a snow covered short runway, about a thousand feet on a DC-9, at max gross.
I have a friend who was on an A-300 with GE engines when they encountered a very severe emergency, involving a 45 degree pitch-up on a go around, airspeed dropped well below 100 knots. The engines were firewalled and all indicator were pegged beyond the red line. Needless to say they survived, but computer readout showed the engines produced almost 100,000 lbs thrust, double the rating. Don't know why the fuel controls let them get this high, maybe the low airspeed, not sure. The engines were borascoped and not even changed. Try that with a recip engine!
Personally, I'm glad I was not on the flight, but I have several thousand hours in turbines and have never lost an engine or had an emergency, a few minor problems yes, but never an emergency, more than I can say with recips. A certain Turbo compounded R-3350 comes to mind.
I baby my engines as I pay the bills, but also because I am on board, but I have always felt, turbines especially turbojets will take much more abuse, and like the old Timex commercial, 'it keeps on ticking'.
Don
href="http://www.matronics.com/Navigator?Commander-List">http://www.matronics.com/Navigator?Commander-List
href="http://forums.matronics.com">http://forums.matronics.com
href="http://www.matronics.com/contribution">http://www.matronics.com/c
[b]
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drwer2
Joined: 24 Sep 2008
Posts: 41
Location: Squaw Valley, CA
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| Posted: Wed Oct 29, 2008 5:58 pm Post subject: Recip vs. turbine |
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Modern turbine engines on FADECs, set to emergency power, the control loop eliminates all but the EGT probes(TiT). So the engines would produce as much power as the turbine section could handle, they would be VERY HOT indeed. No Inlet control, no torque control....nada. As the Turbine inlet temp maxed out, then the control would ramp back the fuel servos. In the meantime, you would get a ridiculous amount of power.
At least thats how its done on PWC and GE engines. I dont know about RR or BMW but Id guess the control laws are similar.
wer
--- On Wed, 10/29/08, nico css <nico(at)cybersuperstore.com> wrote:
| Quote: | From: nico css <nico(at)cybersuperstore.com>
Subject: RE: Recip vs. turbine
To: commander-list(at)matronics.com
Date: Wednesday, October 29, 2008, 4:51 PM
Exactly my sentiments. It's just a shaft with blades on it.
From: owner-commander-list-server(at)matronics.com [mailto:owner-commander-list-server(at)matronics.com] On Behalf Of Don
Sent: Wednesday, October 29, 2008 4:21 PM
To: commander-list(at)matronics.com
Subject: Recip vs. turbine
| Quote: |
"While there may be a certain amount of ego associated with transitioning to Turbines, "
I concede the fuel efficiency to props, be they recip or turbo, but if I am ever in a life threating emergency, give me a high bypass turbojet. They just hang together and produce power, lots and lots of power, push it to the stops and keep it there, it may redline and need changed on the ground but it will get you back to the hanger for the engine change. Seems like I remember being told something like, 'the last 10% of the throttle movement produces 90% of the power', do know, in reverse the difference between 80% and 90% is very amazing on a snow covered short runway, about a thousand feet on a DC-9, at max gross.
I have a friend who was on an A-300 with GE engines when they encountered a very severe emergency, involving a 45 degree pitch-up on a go around, airspeed dropped well below 100 knots. The engines were firewalled and all indicator were pegged beyond the red line. Needless to say they survived, but computer readout showed the engines produced almost 100,000 lbs thrust, double the rating. Don't know why the fuel controls let them get this high, maybe the low airspeed, not sure. The engines were borascoped and not even changed. Try that with a recip engine!
Personally, I'm glad I was not on the flight, but I have several thousand hours in turbines and have never lost an engine or had an emergency, a few minor problems yes, but never an emergency, more than I can say with recips. A certain Turbo compounded R-3350 comes to mind.
I baby my engines as I pay the bills, but also because I am on board, but I have always felt, turbines especially turbojets will take much more abuse, and like the old Timex commercial, 'it keeps on ticking'.
Don
href="http://www.matronics.com/Navigator?Commander-List">http://www.matronics.com/Navigator?Commander-List
href="http://forums.matronics.com">http://forums.matronics.com
href="http://www.matronics.com/contribution">http://www.matronics.com/c
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