Simviation Forum - big piston planes how to use propp pitch re

Feb 6^th, 2007 at 12:44am

osvep Offline
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Costellations,DC4,6,7 have pitch reverser in their propellers(at least I red it).But models does not include this gadget .How real pilots use them?Must be in flying as in turbo props or after landing as in jets ? Undecided

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Reply #1 - Feb 6^th, 2007 at 2:41am

Ivan Offline
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osvep wrote on Feb 6^th, 2007 at 12:44am:

Costellations,DC4,6,7 have pitch reverser in their propellers(at least I red it).But models does not include this gadget .How real pilots use them?Must be in flying as in turbo props or after landing as in jets ? Undecided

DC7 has airbrakes... lowering the maingear

As some runways were quite short in the beginning (no jets) they had to use the reversers after landing. Later on these werent needed on the main airports because with the runway need of the average 60s jet there was enough space available

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Reply #2 - Feb 6^th, 2007 at 4:22pm

beaky Offline
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I don't think "beta" pitch was available in all real-life versions of the aircraft listed... the mighty Boeing 377 had it, but was much heavier than the others.
I've never had any trouble stopping 4-engine propliners (except the Strat) in FS9 without beta pitch... it's not like they're intended for short strips!

As for ground ops, it's just not practical to use the engines for backing up: wasted fuel, flying debris, wear and tear on the engines, etc... the Boeing, for example, only used its reversible props for braking on the runway, it was not intended for use on the ramp.

Side note: I've never heard of beta pitch being used in flight intentionally, even with turbine engines, except in extreme emergencies.

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Reply #3 - Feb 6^th, 2007 at 11:16pm

RitterKreuz Offline
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i heard about a SAAB 340 from some operator way back in the day - apparantly they were high on the approach and slightly fast, the fairly new captain lifted the power lever triggers and pulled the engines into beta to help slow down the speed.

as a result the props did weird aerodynamic things and went into an uncontrollable over speed. the prop RPM gages were pegged off the measurable scale of the gage and as a result the torque, Ng, and ITT also went way out of the envelope which resulted in complete destruction of the engines within a matter of seconds.

they landed the plane without any engine power and ran off the end of the runway... nobody was hurt but in response to this incident an automatic flight idle stop was installed on all saab 340s to prevent the levers from being moved below flight idle when there is no weight on the wheels.

I do know that there is a certain model of king air that can be pulled harmlessly into beta in flight, but pilots are advised against this because of the 1 in a million chance that the props STICK in beta in flight!

It is possible to back up a large aircraft on the ramp using the "reverse" on the props but the biggest risk in doing this is when you try to stop the aircraft is very likely to fall on its tail. part of the C90 training that i went through a couple of years ago focused on "power backs" they told us NEVER to do it... but if we HAD to here is how to do it without breaking anything. Roll Eyes

in real life the reverse of the props is only used as an aide to breaking on the landing roll out, or to control speed during taxi, it is really not used in any other realm of flight.

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Reply #4 - Feb 7^th, 2007 at 12:35am

beaky Offline
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Quote:

i heard about a SAAB 340 from some operator way back in the day - apparantly they were high on the approach and slightly fast, the fairly new captain lifted the power lever triggers and pulled the engines into beta to help slow down the speed.

as a result the props did weird aerodynamic things and went into an uncontrollable over speed. the prop RPM gages were pegged off the measurable scale of the gage and as a result the torque, Ng, and ITT also went way out of the envelope which resulted in complete destruction of the engines within a matter of seconds.

they landed the plane without any engine power and ran off the end of the runway... nobody was hurt but in response to this incident an automatic flight idle stop was installed on all saab 340s to prevent the levers from being moved below flight idle when there is no weight on the wheels.

I do know that there is a certain model of king air that can be pulled harmlessly into beta in flight, but pilots are advised against this because of the 1 in a million chance that the props STICK in beta in flight!

It is possible to back up a large aircraft on the ramp using the "reverse" on the props but the biggest risk in doing this is when you try to stop the aircraft is very likely to fall on its tail. part of the C90 training that i went through a couple of years ago focused on "power backs" they told us NEVER to do it... but if we HAD to here is how to do it without breaking anything. Roll Eyes

in real life the reverse of the props is only used as an aide to breaking on the landing roll out, or to control speed during taxi, it is really not used in any other realm of flight.

I am vindicated... Grin

As little as I know about constant-speed props, I know this much: if you have to go into beta in flight , you've already screwed up.

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Reply #5 - Feb 7^th, 2007 at 1:35am

RitterKreuz Offline
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you've got that right Rotty

i'll say this much - even if i was flying a plane where beta was allowed in flight, i would be VERY hesitant to use it even once.

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Reply #6 - Feb 7^th, 2007 at 3:01am

Ivan Offline
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Tu-95 sometimes uses Beta range inflight.
Tu-154M (not sure about the B) and Il-62 always use reversers just before touchdown
DC-8 and DH Trident could use reversers inflight. Trident for highspeed descent, and DC-8 because it doesnt have airbrakes

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Reply #7 - Feb 7^th, 2007 at 3:36am

RitterKreuz Offline
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seems like i have heard of turbine powered air tractors (crop dusters) using beta as they cross the numbers.

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Reply #8 - Feb 7^th, 2007 at 5:50am

expat Offline
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To change track slightly, the C17 Globe Master can use thrust reverse in flight for tactical drops enabling I believe a descent rate of up 20000 feet per minute be produced. I would like to see it, but not be on board.

Matt

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B1 Boeing 737-800 and Dash8 Q-400

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Reply #9 - Feb 7^th, 2007 at 9:10am

Ivan Offline
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expat wrote on Feb 7^th, 2007 at 5:50am:

To change track slightly, the C17 Globe Master can use thrust reverse in flight for tactical drops enabling I believe a descent rate of up 20000 feet per minute be produced. I would like to see it, but not be on board.

Matt

There is a video of that on flightlevel350

Russian planes: IL-76 (all standard length ones), Tu-154 and Il-62, Tu-134 and An-24RV&&&&AI flightplans and repaints can be found here

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Reply #10 - Feb 7^th, 2007 at 11:19am

expat Offline
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Ivan wrote on Feb 7^th, 2007 at 9:10am:

expat wrote on Feb 7^th, 2007 at 5:50am:

To change track slightly, the C17 Globe Master can use thrust reverse in flight for tactical drops enabling I believe a descent rate of up 20000 feet per minute be produced. I would like to see it, but not be on board.

Matt

There is a video of that on flightlevel350

The video shots of Shuttle cockpit re-entry seem to produce less vibration Shocked

Matt

PETA People Eating Tasty Animals.

B1 Boeing 737-800 and Dash8 Q-400

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Reply #11 - Feb 23^rd, 2007 at 5:50pm

elite marksman Offline
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I believe that the C-130 can also throw its props into full reverse before landing. However, this is only used in emergencies and very short strips.

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Reply #12 - Mar 15^th, 2007 at 10:07pm

DaveSims Offline
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The PC-6 Porter can reverse in flight, its how they race skydivers to the ground, point it straight down and throw it in reverse. Few if any piston engine planes have reverse, though.

As for backing up a C90, just watched a guy do it yesterday trying to get turned around in a tight spot. Definitely a different maneuver to see.

Dave

www.flymcw.com

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Reply #13 - May 31^st, 2007 at 10:01pm

Flying Trucker Ex Member

Hi all

I have watched the military C17s and the C130s back up on the ramp into their parking spots many many times.
The Twin Otter, Aurora and Buffalo are other aircraft I have watched back up many times.

There are days I wish my bugsmashers could back up and wash themselves as well. Grin

Cheers...Happy Landings...Doug

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