What are the conditions for Max range and endurance for propeller driven aircraft?

What are the conditions for Max range and endurance for propeller driven aircraft?

Therefore, weight of fuel consumed per hour will be minimum when thrust required is minimum. We know that for minimum thrust required, CL/CD should be maximum. Therefore for a jet aircraft, maximum endurance occurs when the airplane is flying at a velocity such that TR is minimum.

Why are larger propellers more efficient?

The larger the diameter of the propeller, the slower the shaft speed RPM that is required to absorb the same power. Therefore, for an efficient propeller, not only should the diameter be as large as possible but, as a result, the shaft speed needs to be slow.

What effect does a propeller with a high blade angle have on performance?

Increasing propeller blade angle increases the AOA and produces more lift and drag; this action increases the horsepower required to turn the propeller at a given rpm. Since the engine is still producing the same horsepower, the propeller slows down. If the blade angle is decreased, the propeller speeds up.

Will a bigger prop mean more speed?

The lower the prop pitch, the better your hole-shot. However, this comes at a price: top speed. The lower pitch makes the engine reach maximum rpm at slower speeds. Conversely, a higher pitch will deliver greater top speeds, but slower acceleration.

Which is better 3 or 4 blade prop?

3 or 4 Blades? A 3 blade propeller usually offers top speed performance while a 4 blade propeller provides maximum thrust and smooth cruising operation. Four blades have some features of their own, though. They often provide more lift at the stern which will help accelerate the hull, especially if it is stern heavy.

What is the benefit of a constant speed propeller?

Some of the benefits of a constant speed propeller: Optimum RPM is set with the propeller control, allowing the propeller to adjust automatically to the most efficient pitch angle. As airspeed increases, such as in a descent, propeller pitch is automatically increased keeping the RPM the same.

What is maximum range speed?

LRC speed is interrelated with maximum-range cruise (MRC) speed, which is the speed that will provide the furthest distance traveled for a given amount of fuel burned and the minimum fuel burned for a given cruise distance.

What is the efficiency of a propeller engine?

The speed of an airplane model flying straight and level at full throttle has been measured to be 252 km/h. The efficiency of the propeller is assumed to be 80%. From bench tests at the same rotational speed the engine power is known to be 1.5 kW.

What are the criteria for selecting a propeller?

Selection Criteria 1 Present prop diameter 2 Present prop pitch 3 Right or left hand prop rotation (clockwise is right hand) 4 Number of blades 5 Material (Usually aluminum or stainless steel)

What happens to the thrust of a propeller?

It decreases with increasing flight speed, until it reaches zero: no thrust is generated. When the flight speed is increased even more (e.g. by diving), the propeller acts like a windmill: it tries to turn the engine, which might be fatal for the engine.

How much power is lost in the swirl of a propeller?

The amount of swirl depends on the rotational speed of the engine and eats up energy, which is not available for thrust anymore. Typical, well designed propellers loose about 1% to 5% of their power in the swirl of the propeller wake.