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).

Filter by
Sorted by
Tagged with
0
votes
0answers
78 views

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 ...
6
votes
1answer
1k 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 ...
1
vote
1answer
180 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 ...
3
votes
3answers
167 views

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 ...
10
votes
4answers
8k views

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 ...
7
votes
3answers
550 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 ...
0
votes
0answers
26 views

What are examples of power-available and thrust-available curves for piston and turboprop engines, with constant-speed propellers in each case?

Considering the actual thrust or power delivered by the prop to the airframe, what are examples of power-available and thrust-available curves for piston and turboprop engines, with constant-speed ...
0
votes
3answers
155 views

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 ...
0
votes
0answers
44 views

Why Turboprop engines are better than turbojet at low altitude and speed? [duplicate]

Please explain the Aerodynamic or engine considerations which makes turboprop more efficient at low altitude n low speed as compared to turbo jet.
2
votes
1answer
174 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 ...
1
vote
1answer
147 views

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 ...
12
votes
2answers
793 views

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-...
4
votes
2answers
311 views

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 ...
19
votes
3answers
3k views

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 ...
0
votes
1answer
276 views

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 ...
0
votes
1answer
160 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 ...
11
votes
5answers
6k views

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 :)
5
votes
1answer
358 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 ...
20
votes
4answers
4k views

How does turbine efficiency compare with internal combustion engines if all the turbine power is converted to mechanical energy?

It is widely know that early turbojets guzzled fuel and created thrust simply by spewing accelerated matter out the back. Modern jets have come a long way in earning a better reputation with ...
5
votes
1answer
352 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 (...
24
votes
3answers
4k views

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 ...
1
vote
0answers
179 views

Why use turbofan engines for high altitude flight?

I noticed that a lot of high altitude aircraft have turbofans for engines. So I researched and figured out that turboprop engines are more efficient. But most high altitude aircraft like the Global ...
6
votes
2answers
635 views

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.
0
votes
1answer
128 views

Why can't turbojets or turbofans be overtemped or overtorqued the way turboprops can?

Turboprops that aren't FADEC controlled can be overtorqued or overtemped if the power lever is moved too far forward yet I have never heard of a jet that can't be "firewalled", FADEC or not. Why is ...
6
votes
1answer
219 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 $$ m_\mathrm{Fan} = 0.1 \times m_\mathrm{Turbine} $$ ...
0
votes
1answer
198 views

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, ...
1
vote
0answers
39 views

turboprop thrust relative to the jet's propulsion [duplicate]

What is the thrust ratio in a turboprop between propeller and its jet exhaust, and is the jet exhaust necessary for flight? Once the turbines are spinning, it seems the exhaust is waste product. This ...
2
votes
2answers
1k views

Turboprop vs turbofan (in regional aircraft)

I'm trying to figure out WHY turboprops are more efficient at lower altitudes and airspeed, while turbofans are better at faster speeds and higher altitude. Simplistically, my explanation is the ...
4
votes
2answers
284 views

Do a turboprop’s compressor and turbine rotors windmill when the engine is shut down and feathered?

If a jet engine is shut down in flight, it continues to turn due to the aircraft’s forward motion forcing air through the engine, causing it to “windmill” in the airflow. Is this also true for ...
4
votes
1answer
735 views

How does propellers' pitch change during the use of reverse thrust in turboprop/propfan propelled planes?

Which way do proplellers turn during the use of reverse thrust in turboprop/propfan propelled planes: A) Do the leading and trailing edges of propellers remain the same or... B) Do the propellers ...
0
votes
3answers
610 views

why are turboprop/turboshaft engines rated only in horsepower and never in ft-lbs of torque like diesel engines or electric motors?

I realize torque and horsepower are essentially the same measurement since horsepower is simply torque over time. But I'm curious as to why diesel engines or electric motors always provide torque ...
26
votes
8answers
4k views

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?
0
votes
1answer
409 views

How to compare turboprop engines and with which values?

I have found this website that lists a lot of turboprop engines. I would like to compare them with as few values as possible. As an example, there are tons of different values that describe a jet ...
1
vote
1answer
2k views

Are turboprops less safe then jets?

On a recent trip to an airport, I noticed a large number of Bombardier Dash 8s. I wanted to know - are turboprops less safe than traditional jets like the 737 or A320? For instance, I would imagine ...
22
votes
2answers
4k views

Why aren't there any widebody propliners for the high-density short-haul markets?

Jetliners come in both narrowbody (one aisle) and widebody (two or more aisles) versions, but all propliners, to the best of my knowledge, are narrowbody aircraft. Now, granted, one of the big ...
25
votes
3answers
5k views

Why would a turboprop rev down just before going full throttle during takeoff?

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 ...
3
votes
1answer
326 views

How does the load transfer from a prop to the airframe?

I was just watching this video... Restoration and startup of a Wright 1820 Cyclone ...and it got me thinking: a propeller shoves back air, and this creates a forward force on the prop. The prop ...
-2
votes
1answer
370 views

Where should I find a Pratt & Whitney Canada PT6 operator's manual?

I'm studying the PT6 in detail but the infos I get around the web are sometimes lacking in depth of informations. I'm pretty much interested in the power curve vs RPM of this engine. Where should I be ...
4
votes
2answers
1k views

Why is there still a preference for turboprop airliners over the new regional jets? [duplicate]

In the 1950s and in the early 1960s, jets were mostly available as fighter/military or big, long haul aircraft. Regional aviation was based primarily on piston aircraft that could operate in smaller ...
3
votes
3answers
458 views

In a pusher configuration with turboprop(s), how is the superhot exhaust avoided?

I actually looked around for turboprops in a pusher configuration, and so far I only found one: P180 Avanti. You can see the propellers are behind the turbine, and in fact it looks like two exhaust ...
24
votes
3answers
6k views

Why are turboprop intakes placed below the propeller?

On many turboprop aircraft, such as the A400M and the ATR 72, it seems that the air intake tends to be placed below the propeller (images: Wikipedia): source source Given that mounting the intake ...
0
votes
2answers
357 views

How long does it take for a propeller engine to spool-up?

To build further upon the question Why does a turboprop lag?, the following: Assuming a propeller engine is running in idle and the throttle lever is switched to full thrust instantaneously at t = 0 ...
7
votes
5answers
1k views

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 ...
3
votes
1answer
179 views

What do these explanations for propellor RPM increases mean?

I have read in a book that if the engine RPM increases while descending, the probable causes are: Engine transfer bearing leaking excessively Excessive friction in blade bearings I am not able to ...
2
votes
0answers
178 views

What could cause an engine shutdown on a Q400 with CDS codes 732, 907, 915 and 938?

A Bombardier Q400 displays error code 938 on the Central Diagnostics System(CDS), which is attributed to turbomachinery chip detector. An examination shows debris in the detector hitch which is ...
2
votes
3answers
379 views

Why is the first turbine in a turboprop (or turboshaft) connected to the compressor?

Typically the first turbine after the combustion chamber drives the compressor as shown in this picture. (wikimedia.org) This first turbine spins the fastest and harvests the most energy from the ...
2
votes
1answer
1k views

FADEC or EEC for PT6-42A…is it feasible?

In a response to a You-tube clip showcasing Piper's M600 single turbo prop, a viewer dismissed it as an inferior engine compared to a GE (probably an H-80 series) due to lack of FADEC or Electronic ...
5
votes
2answers
3k views

Is a turboprop or a turbofan more eco-friendly?

If we compare them, which one wins? Why? And, what about CO2 emissions?
5
votes
2answers
442 views

How do the compressor stages keep spinning after start in a free turbine?

In a ‘free’ (or uncoupled) turbine engine (specifically the Rolls Royce C20-250), what is spinning the compressor blades (N1) after start? It can’t be N2, because it’s a free turbine. I don’t think ...
1
vote
1answer
594 views

What is NH overspeed test and how it is preformed on DHC Q400 aircraft?

In the Aeroplane Operating Manual of DHC Q400 aircraft it is written that, at the time of normal engine shutdown, the engine system tests the NH overspeed circuitry by using it to shutdown the engine. ...