What is the purpose of the reduction gearbox in turboprop?

#2) Speed Reduction Gearbox The speed reduction gearbox is a type of transmission system used in turboprop engines. It’s used to lower the engine’s revolutions per minute (RPM). Turboprop engines turn propellers by outputting RPM. The higher the RPM output, the faster the propellers will turn.

What is the purpose of reduction gears?

Equipment used to convert the output shaft revolutions of the main engine to those required to rotate the propeller. Gearboxes consist of meshing teeth on pinions and wheels which transfer power from a drive shaft to a driven shaft and reduce speed.

What is the purpose of the reduction gearbox on a pt6?

It has one stage on the small engines and two stages on the medium and large ones. For turboprop use, this powers a two-stage planetary output reduction gearbox, which turns the propeller at a speed of 1,900 to 2,200 rpm. The exhaust gas then escapes through two side-mounted ducts in the power turbine housing.

Why Are turboprops more efficient?

It is more efficient at low speeds to accelerate a large amount of air by a small amount, compared to moving a small amount of air by a large degree, so a low disc loading (thrust per disc area) increases the turboprop aircraft’s energy efficiency, and this reduces the fuel use.

Do jet engines have transmissions?

More powerful propeller driven aircraft do have a “transmission” in the form of a constant speed propeller. This type of propeller adjusts its pitch to give the equivalent of low gear when climbing out and the equivalent of overdrive when cruising. There is no equivalent for jets.

Why is it necessary to couple the fan to the turbine with a gearbox?

It does, when both the fan and the compressor can rotate at their optimum speed, and when the gearbox does not add much friction. The gearbox is located between the front fan and the rest of the engine. It lets the front fan spin at a lower rate than the main shaft.

How much does a PT6 cost?

PT6A-42A Premium Flat Rate Overhaul For a guaranteed firm price of US$415,000, your Premium Flat Rate Overhaul will include mandatory replacement of compressor turbine (CT) blades with new P&WC genuine parts.

How much fuel does a PT6 burn?

The turbine inlet temperature inside the engine goes to almost 2,000 degrees F within 30 seconds of start. You are burning about 26 gallons per hour here, at idle.

How does a turboprops engine work?

For turboprops, very little thrust is produced by the exhaust directly (2\%-3\% of total thrust output), the propeller does the work of converting heat to thrust via a gearbox driven by the expansion turbine.

Why do turboprops use constant-speed propellers?

To maintain propeller efficiency across a wide range of airspeeds, turboprops use constant-speed (variable-pitch) propellers. The blades of a constant-speed propeller increase pitch as aircraft speed increases. Another benefit of this type of propeller is that it can also be used to generate reverse thrust to reduce stopping distance on the runway.

Are turboprop engines less safe?

Setting aside mechanical complexity, turboprop engines themselves are not less safe, but rather the resulting installation effects add a layer of risk that is less prominent in multi-engine turbofan aircraft.

Why are turboprops so popular for regional flights?

Due to the propulsive efficiency curve, they’re most efficient at speeds slower than 400 knots. While expensive, they’re extremely reliable. This makes turboprops the perfect engine type for relatively short regional flights.