Questions tagged [turboprop]

A turboprop engine is a type of turbine engine which drives an aircraft propeller to produce thrust (as opposed to a jet engine, where the turbine exhaust provides thrust directly).

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4
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1answer
102 views

How does a C208B's climate control system that utilizes bleed air for cabin heat work?

I'm studying the systems on my first turbine-engine aircraft, specifically, a C208B. I know that there is "bleed air heat" that mixes with re-circulated cabin-air. I know that the bleed air ...
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1answer
343 views

What's up with the long exhaust stack I saw on a Cessna Caravan?

Our local airport is regularly visited by Cessna caravans flying cargo. This week I saw one parked outside the FBO building that had its exhaust stack bent down to lead under the cowling, where it was ...
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5answers
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Does the engine mount of a turboprop engine in an aircraft experience engine torque?

When the turboprop engine is active, the propeller shaft rotates and causes the propeller to rotate as well, which in turn generates thrust. The propeller shaft rotates because of the torque (or ...
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1answer
203 views

What would be the advantage of a Puller vs. Pusher configuration on Embraer's new Turboprop?

Embraer recently teased a turboprop aircraft with aft-mounted, open rotor engines. Why would this aircraft not use a pusher configuration? The reasons that are frequently stated as a benefit for a ...
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1answer
8k views

How to calculate the thrust of a piston or turboprop engine? [duplicate]

This spawns from a related question. Propeller-drive engines (piston/turboprops) seem to always list their output in horsepower or kilowatts, which are units of power. I want to know the engine's ...
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What does the "MAX EMR PWR" lever do in a Quest Kodiak?

On a photo of the Quadrant of a Kodiak Quest 100 there was an additional red lever to the left of the throttle (black handle) labeled with "MAX EMR PWR". Can anyone explain what what this ...
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5answers
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Is it incorrect to refer to a C-130 as a jet?

In this article by CNN, the C-130 involved in the unfortunate crash in Savannah, GA is referred to as a "jet." Is this considered proper usage? I'm not looking for public opinion here but official ...
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0answers
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why are modern rotor airfoils placed and set up in a compressor at a higher angle of incidence?

why is it that in modern compressors in gas turbine engines like the J79 the rotor blades are set up at a higher angle of incidence (more aligned to the axial axis) compared to older engines. I also ...
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1answer
507 views

What is "alternate takeoff" in this PT6A performance table?

I am flight mechanic, and I would like to know about this performance limitation: What is the definition of alternate take off? Why is the alternate take off temperature limit (ITT) lower than max. ...
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3answers
905 views

Why do propellers have less theoretical range (i.e. range ignoring impatient passengers wanting to go fast) than jets, despite greater efficiency?

I was playing around with the breguet range equation recently, and came across a suprising result, that propellers have less range than jets, despite having greater efficiency. The range equation for ...
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1answer
388 views

Is it safe to use a propeller plane to fly commercially over the Tibetan Plateau?

I saw this youtube video today: Flying over Mt Everest. A lovely view of stunning nature - quite spectacular. However, I looked up the plane - or at least what I think is the plane - and found that it ...
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How to decide the diameter of a propeller and number of propellers needed in a UAV I am designing? [closed]

I want to design a turboprop aircraft. I know all the design parameters such as lift, thrust, weight etc at a given flight stage. I want to know what the size of the propeller should be.
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1answer
232 views

What is prop RPM control logic on PC-12?

Pilatus PC-12 has a constant speed propeller, but it does not have a prop control lever in cockpit, just a power lever and small fuel on/off lever. So how does it determine the prop RPM? Does it ...
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1answer
2k views

Why do propellors have white markings on their tips? [duplicate]

Why do propellors have white markings on their tips? Here are a couple of examples:
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1answer
180 views

What is the difference between RTOP, MTOP, and MCP?

I am currently learning how to fly the SD3-60 (Shorts) Aircraft, and I am trying to gain an understanding of RTOP (reserved take off power), MTOP (max take off power), and MCP (max continuous power). ...
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3answers
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What turbine blade alloy did the Jendrassik Cs-1 use?

Wikipedia says that the first turboprop aircraft engine was the Jendrassik Cs-1 invented in Hungary by György Jendrassik. It says it was supposed to run at 1000 hp but "combustion problems" limited ...
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0answers
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How does the maintenance cost of turboprops compare to turbofans?

I was initially under the impression that the added complexity of gearing in a turboprop would lead to more maintenance. Then I found out geared turbofans are becoming fairly common so there should be ...
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PT-6 Starting problems - PT6A - 67B, installed on a PC12

we are having trouble starting our PC12. After introducing fuel at stabilized 13% ng, the engine spools up very slowly - it takes forever to get through 20, 30, 40%ng. We've had several hung starts, ...
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164 views

How does one choose the number of blades and the diameter required for a turboprop propeller?

I am interested in the preliminary design of a regional aircraft that uses turboprops as the propulsion method. Following considerable research online about propeller design (disk theory, BEM...) I am ...
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1answer
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Do any regional turboprop aircraft have leading edge high lift devices?

I'm currently working on an aircraft design project for a regional turboprop. I wanted to know if there are any regional TP's with leading-edge devices. It seems that a lot of them have deicing boots ...
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2answers
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Do aircraft that operate at lower altitudes tend to have more cycles?

I've heard that aircraft cycles depend on the number of missions, regardless of the distance, because the pressurisation of the aircraft at altitude is what causes cumulative damage to the fuselage. ...
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Why would a turboprop be better than an internal combustion engine for a UAV?

Let us consider a UAV, long endurance high altitude (~26,000ft). Why would a user (most probably military) go for a turboprop rather than an internal combustion engine?
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Why are high-bypass turbofans faster than turboprops?

The turboprop, and especially the high-blade-count propfan, differs from the high-bypass turbofan principally in throwing away the draggy outer ducting. This makes it easier to obtain a greater ...
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At what range does the turbofan start to become more economical than a turboprop? [duplicate]

By more economical I only mean 'burns less fuel'. I'm under the impression that at optimal cruise speed and altitude a turbofan will burn less fuel per mile per passenger than a turboprop, but I might ...
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Why do aircraft with turboprop engine have black painted anti-icing system?

Everyday as I watch aircraft with turboprop engines, a question pops up: Why do aircraft with turboprop engines have black painted anti-icing system? For instance:
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1answer
316 views

why some airplanes have their exhaust gases vectored above the wing?

I was looking at images of the SkyCourier shown below and i have noticed the asymmetrical exhaust pipes in both engines (one pointing up and one is straight), doing my research on the internet, i ...
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Make a 3 engine turboprop electric or steam hybrid aircraft?

Was thinking about this, have a 2 engine regular turboprop with a third electric engine for extra performance (imagine a DC3 like the Conroy Tri-Turbo-Three). The 3rd electric engine would be run from ...
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1answer
2k views

What is this strange looking aircraft?

This website describes twin-tail aircraft. It has a photo of a strange-looking aircraft with a twin tail, and turboprop engines, resembling a C-130 Hercules. There was no registration or tail number ...
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1answer
242 views

Can turboprops use a recuperator?

A recuperator is a device which extracts heat from the exhaust of a turbine and transfers it to the front air. This heats the air, which means the turbine uses less fuel to heat the combustion chamber ...
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Why do we refer to "power" for turboprop engines and "thrust" for turbojet/fan engines?

In jet engines, I read that thrust is related to the fuel flow rate, whereas in turboprop engines power produced is related to the fuel flow rate. What is the reason and brief math behind this?
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What is the airplane type in this formation seen above Eugene, Oregon?

This flight of 2 flew by my house in Eugene, Oregon recently. I assume they're military pilot trainers but I am having trouble coming up with an ID.
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1answer
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How big is the TP400-D6 turboprop installed on the A400M?

I am trying to re-create the A400M TP400-D6 engine in CAD, mainly the nacelle and propeller, yet I can't find any detailed dimensions for it. Europrop specifies a 0.92m diameter for the TP400-D6, so ...
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Why don't NK-12 powered contra-rotating propellers turn in equal rpm?

The Kuznetsov NK-12 is a Soviet turboprop engine of the 1950s, designed by the Kuznetsov design bureau. The NK-12 drives two large four-bladed contra-rotating propellers, 5.6 m (18 ft) diameter (NK-...
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1answer
234 views

How heavy are turbofan and turboprop propeller blades?

How heavy are the blades from Turbofan (CFM56-5B, RRTrent800, PW4062A) and Turboprop (PW127M) engines? Is there a general appromixation like $$ m_\mathrm{Fan} = 0.1 \times m_\mathrm{Turbine} $$ ...
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Why is the Tu-95 so efficient despite having propellers that spin faster than the speed of sound?

I've ready many, many times that propellers are not efficient near the speed of sound because it's so hard to get a tip-speed above Mach 1. Then I came across this: It's the Tu-95 "Bear", a ...
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3answers
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Where does fuel from the boost pumps go before engine start?

For example let’s take the PT6A-27. In every video related to engine start I see, the fuel boost pump is turned on, and then the fuel pressure goes up. Example: My ...
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4answers
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How are turboprops and other propeller planes pressurized?

I know how most turbofan jets are pressurized: But it can't be the same with turboprops, as I don't understand how propellers can take in the air. Yet, planes like Q400s can fly above 8000', all the ...
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1answer
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Turboprop vs Turbofan: How to compare Specific Fuel Consumption

I understand that Turboprop engines have a lower Specific Fuel Consumption (SFC) than Turbofan engines, on average. I want to see this for myself by analysis, ideally by comparing values of SFC for ...
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Why do turbofans go faster than turboprops? [duplicate]

Can someone explain why turboprops are less effective in terms of thrust than turbofans? But at the same time, why turboprops burn less fuel? For example, the Bombardier Q400/De Havilland Dash 8 has a ...
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What is the purpose of having contra-rotating props on an aircraft?

Why do planes, like the famous XF-11 and the Tu-95, have contra-rotating props? What is their purpose? Image credit: Mike Freer / Touchdown-Aviation / Wikimedia
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Is a turboprop or a turbofan more eco-friendly?

If we compare them, which one wins? Why? And, what about CO2 emissions?
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Is it possible to drive a prop directly from a jet engine without a gearbox?

I'm studying turbojets, turbofans, and turboprops. I can see that, for the latter engine configuration, a gearbox is necessary so that the propeller rotates at a lower velocity than the main ...
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1answer
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Which are typical rpm values for aeronautical turbines?

I wonder which of these has higher or lower rotational speed: turboshaft turbofan turbojet turboprop Does anybody know the typical speeds for these kind of engines?
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Why are propellers de-iced before the engines are started, and does ice on the fuselage affect the flight characteristics of the plane?

I recently flew on a flight out of Montreal on a DHC8 turboprop. The plane had been parked at the airport overnight during a winter storm, and as I walked out to the plane, there were visible icicles ...
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1answer
293 views

Why are there no large turboprop passenger airliners? [duplicate]

If turboprop engines are more efficient than turbofan/jet engines at lower speeds, and have a lower specific fuel consumption, why are there no large passenger airliners that utilize the turboprop ...
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5answers
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Is a turbocharged piston aircraft the same thing as turboprop?

Simple question, and I've always assumed that they are the same thing, but I'd like feedback from someone who knows more than me :)
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1answer
602 views

Why is the generator turned back off for starting the second engine on a King Air?

The engine start procedure for the Beechcraft King Air B200 says (emphasis mine): Right Ignition and Engine Start Switch – ON [R FUEL PRESS] annunciator – OFF Right Condition Lever – LOW IDLE (...
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3answers
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Would jet fuel for an F-16 or F-35 be producible during WW2?

I understand that different types of engines use different types of fuel, and as the description of the [jet] tag says, turboprops and jet engines use different types of fuel. So if – like in the ...
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1answer
364 views

What could cause lower torque than normal during cruise in a King Air 300?

At approx FL200 in our King Air 300 we experience a vibration and notice the torque drop for both engines. The torque stays about 10% lower than normal in cruise. The vibration is intermittent and ...
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Why are propeller engines uncommon on airliners?

My experience in aviation is essentially zero, but looking at Wikipedia it seems like the Tu-95 Bear offers high subsonic speed and extreme range. I assume that turboprop engines are more fuel ...