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Why would a turboprop rev down just before going full throttle during takeoff?
Clash Royale CLAN TAG#URR8PPP
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The only turbprop I've travelled is the ATR 72. I've noticed that the props' rev go down (for like a second, the sound also goes down) just before engaging full throttle in order to takeoff. I've included a video (video is not mine), this thing happens at 1:40. Why the RPM drops for a sec? Or is this just the sound?
takeoff propeller turboprop throttle sound
edited 4 hours ago
ymb1
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Abrar Borno
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up vote
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down vote
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The only turbprop I've travelled is the ATR 72. I've noticed that the props' rev go down (for like a second, the sound also goes down) just before engaging full throttle in order to takeoff. I've included a video (video is not mine), this thing happens at 1:40. Why the RPM drops for a sec? Or is this just the sound?
takeoff propeller turboprop throttle sound
edited 4 hours ago
ymb1
59.9k5188315
asked 6 hours ago
Abrar Borno
211
New contributor
Abrar Borno is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |Â
up vote
3
down vote
favorite
up vote
3
down vote
favorite
The only turbprop I've travelled is the ATR 72. I've noticed that the props' rev go down (for like a second, the sound also goes down) just before engaging full throttle in order to takeoff. I've included a video (video is not mine), this thing happens at 1:40. Why the RPM drops for a sec? Or is this just the sound?
takeoff propeller turboprop throttle sound
edited 4 hours ago
ymb1
59.9k5188315
asked 6 hours ago
Abrar Borno
211
New contributor
Abrar Borno is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
The only turbprop I've travelled is the ATR 72. I've noticed that the props' rev go down (for like a second, the sound also goes down) just before engaging full throttle in order to takeoff. I've included a video (video is not mine), this thing happens at 1:40. Why the RPM drops for a sec? Or is this just the sound?
takeoff propeller turboprop throttle sound
takeoff propeller turboprop throttle sound
edited 4 hours ago
ymb1
59.9k5188315
asked 6 hours ago
Abrar Borno
211
New contributor
Abrar Borno is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 4 hours ago
ymb1
59.9k5188315
asked 6 hours ago
Abrar Borno
211
New contributor
Abrar Borno is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 4 hours ago
ymb1
59.9k5188315
edited 4 hours ago
ymb1
59.9k5188315
edited 4 hours ago
ymb1
59.9k5188315
59.9k5188315
asked 6 hours ago
Abrar Borno
211
New contributor
Abrar Borno is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 6 hours ago
Abrar Borno
211
asked 6 hours ago
Abrar Borno
211
211
New contributor
Abrar Borno is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Abrar Borno is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Abrar Borno is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
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2 Answers
2
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oldest
votes
up vote
5
down vote
Most likely this is happening after the pilot advances the power lever -- but the power lever controls both throttle (fuel flow, in a turbine), and propeller pitch.
The propeller can change pitch pretty quickly, while the turbine takes longer to increase power (increased fuel flow must produce hotter combuster air, which must then spin up both the turbine-compressor section, and the independent shaft power turbine connected to the gear box and propeller). Usually, the engine's rotating parts will change RPM faster than the ones that spin the (relatively large) propeller, so you may hear the "whine" or "whistle" of the primary shaft spooling up before the propeller noise starts to rise, possibly even while the propeller is still slowing down from the pitch increase.
answered 5 hours ago
Zeiss Ikon
1,1039
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up vote
1
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Because the pilot is taxiing the airplane with the props in the beta range (turboprops turn into landsharks if you don’t do this and you end up really riding the brakes to keep the speed down), then on takeoff, the propellers move into a maximum power setting, the engine snarls and slows a bit under the increased workload.
answered 1 hour ago
Carlo Felicione
35k263133
add a comment |Â
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
5
down vote
Most likely this is happening after the pilot advances the power lever -- but the power lever controls both throttle (fuel flow, in a turbine), and propeller pitch.
The propeller can change pitch pretty quickly, while the turbine takes longer to increase power (increased fuel flow must produce hotter combuster air, which must then spin up both the turbine-compressor section, and the independent shaft power turbine connected to the gear box and propeller). Usually, the engine's rotating parts will change RPM faster than the ones that spin the (relatively large) propeller, so you may hear the "whine" or "whistle" of the primary shaft spooling up before the propeller noise starts to rise, possibly even while the propeller is still slowing down from the pitch increase.
answered 5 hours ago
Zeiss Ikon
1,1039
add a comment |Â
up vote
5
down vote
Most likely this is happening after the pilot advances the power lever -- but the power lever controls both throttle (fuel flow, in a turbine), and propeller pitch.
The propeller can change pitch pretty quickly, while the turbine takes longer to increase power (increased fuel flow must produce hotter combuster air, which must then spin up both the turbine-compressor section, and the independent shaft power turbine connected to the gear box and propeller). Usually, the engine's rotating parts will change RPM faster than the ones that spin the (relatively large) propeller, so you may hear the "whine" or "whistle" of the primary shaft spooling up before the propeller noise starts to rise, possibly even while the propeller is still slowing down from the pitch increase.
answered 5 hours ago
Zeiss Ikon
1,1039
add a comment |Â
up vote
5
down vote
up vote
5
down vote
Most likely this is happening after the pilot advances the power lever -- but the power lever controls both throttle (fuel flow, in a turbine), and propeller pitch.
The propeller can change pitch pretty quickly, while the turbine takes longer to increase power (increased fuel flow must produce hotter combuster air, which must then spin up both the turbine-compressor section, and the independent shaft power turbine connected to the gear box and propeller). Usually, the engine's rotating parts will change RPM faster than the ones that spin the (relatively large) propeller, so you may hear the "whine" or "whistle" of the primary shaft spooling up before the propeller noise starts to rise, possibly even while the propeller is still slowing down from the pitch increase.
answered 5 hours ago
Zeiss Ikon
1,1039
Most likely this is happening after the pilot advances the power lever -- but the power lever controls both throttle (fuel flow, in a turbine), and propeller pitch.
The propeller can change pitch pretty quickly, while the turbine takes longer to increase power (increased fuel flow must produce hotter combuster air, which must then spin up both the turbine-compressor section, and the independent shaft power turbine connected to the gear box and propeller). Usually, the engine's rotating parts will change RPM faster than the ones that spin the (relatively large) propeller, so you may hear the "whine" or "whistle" of the primary shaft spooling up before the propeller noise starts to rise, possibly even while the propeller is still slowing down from the pitch increase.
answered 5 hours ago
Zeiss Ikon
1,1039
edited 3 hours ago
answered 5 hours ago
Zeiss Ikon
1,1039
answered 5 hours ago
Zeiss Ikon
1,1039
answered 5 hours ago
Zeiss Ikon
1,1039
1,1039
add a comment |Â
add a comment |Â
up vote
1
down vote
Because the pilot is taxiing the airplane with the props in the beta range (turboprops turn into landsharks if you don’t do this and you end up really riding the brakes to keep the speed down), then on takeoff, the propellers move into a maximum power setting, the engine snarls and slows a bit under the increased workload.
answered 1 hour ago
Carlo Felicione
35k263133
add a comment |Â
up vote
1
down vote
Because the pilot is taxiing the airplane with the props in the beta range (turboprops turn into landsharks if you don’t do this and you end up really riding the brakes to keep the speed down), then on takeoff, the propellers move into a maximum power setting, the engine snarls and slows a bit under the increased workload.
answered 1 hour ago
Carlo Felicione
35k263133
add a comment |Â
up vote
1
down vote
up vote
1
down vote
Because the pilot is taxiing the airplane with the props in the beta range (turboprops turn into landsharks if you don’t do this and you end up really riding the brakes to keep the speed down), then on takeoff, the propellers move into a maximum power setting, the engine snarls and slows a bit under the increased workload.
answered 1 hour ago
Carlo Felicione
35k263133
Because the pilot is taxiing the airplane with the props in the beta range (turboprops turn into landsharks if you don’t do this and you end up really riding the brakes to keep the speed down), then on takeoff, the propellers move into a maximum power setting, the engine snarls and slows a bit under the increased workload.
answered 1 hour ago
Carlo Felicione
35k263133
answered 1 hour ago
Carlo Felicione
35k263133
answered 1 hour ago
Carlo Felicione
35k263133
answered 1 hour ago
Carlo Felicione
35k263133
35k263133
add a comment |Â
add a comment |Â
Abrar Borno is a new contributor. Be nice, and check out our Code of Conduct.
Abrar Borno is a new contributor. Be nice, and check out our Code of Conduct.
Abrar Borno is a new contributor. Be nice, and check out our Code of Conduct.
Abrar Borno is a new contributor. Be nice, and check out our Code of Conduct.
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