Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: popeye on September 21, 2024, 09:48:43 AM
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A friend is reading a novel in which the author writes about a pilot flying a four-engine turboprop plane and "points the nose down, lowering the altitude by several thousand feet in a dive that almost stalls the engines". He asked me about the technical accuracy, but I couldn't find any info so I ask here: could a high-speed dive cause a turboprop engine to stall?
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Define Turboprop?
A turbo charged engine, or a Turbine Engine with prop?
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The book just says "turboprop", so I assume it is a turbine engine with a prop. I'm guessing that is the most common meaning.
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Doesn't seem likely. i have 8000+ hours on verious turboprop airplanes and none of them had cautions about speed affecting engine performance.
Suspect Author's imagination.
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Thanks Busher, I'll pass that along.
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Author is wrong but there are details he’s not supplying to make it believable.
Maybe the initial push over meant the air intakes were temporarily no longer aligned for proper air flow in causing compressor stall……….kind of like climbing too steeply in an airliner.
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Compressor stall. That reminds me on an incident at the Anchorage Airport, back in the 80's. I worked on the Trans-Alaska Pipeline from 77 to 98, working week On week Off. Because I lived in Kenai AK, I flew in on a local Airline on the morning of Crew change to catch charter to the Station I was going to. While sitting in the Restaurant looking out on the flight line, there was an Alaska Airlines 727 at a near by gate. There was some kind of mechanical issue with ground crew in the cockpit, and and discussing issues on the tarmac. A lift box truck back up to the left rear passenger door, raised the bed up, and put a cover on the Left Engine intake. about 3 or 4 minutes later, you could hear an engine starting to spin up. I didn't think to much about it, then a real short time later, we heard 3 quick booms. The big windows in the restaurant shook real bad at each boom. then you heard the engine start to spin down.
The crew on the plane came boiling out of the plane looking around, gesturing to each other and all of them talking. about 2 minutes later, an Alaska Airlines pickup pulls up, and stops, a man gets out and HE started gesturing and talking, all the original ground crew stood there with their mouths shut and heads hanging down. Not sure what happened after that, had to go catch my charter flight.
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Compressor stalls happen most often at high angles of attack. Not at high speeds. Firthermore, compressor stalls happen far less often in turboprops - the prop root helps induce airflow into the intake.
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If the airflow is across the intake from ANY direction other than straight in is high enough, you can run into compressor stall.
I used to design induction systems on high horsepower automobiles and then test them on the shuttle landing facility at speeds up to 300mph.
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Doesn't seem likely. i have 8000+ hours on verious turboprop airplanes and none of them had cautions about speed affecting engine performance.
Suspect Author's imagination.
Agree with Busher’s assessment, especially “Suspect Author’s imagination”. Author would be better off and believable doing research, to include interviewing a pilot with high time in turboprops, to develop a mechanical or pilot induced issue for the intended outcome.
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Author could have gotten away by replacing “stalling” with “overspeeding” because the rest of the story may reference the effects on the engines.