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Questions tagged [variable-pitch]

A controllable-pitch propeller (CPP) or variable-pitch propeller is a type of propeller with blades that can be rotated around their long axis to change the blade pitch.

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10 votes
2 answers
795 views

Do constant maximum lift to drag ratio variable pitch propeller exist?

Are there variable pitch propellers, where pitch is set so that the blades constantly are at their maximum lift to drag ratio AoA, whatever the incoming relative wind speed & direction? Such a ...
7 votes
2 answers
673 views

What is the difference in performance between variable pitch prop and two fixed propellers for take-off and cruise speeds?

Push-pull configuration aircrafts usually feature identical engines and propellers working only in tandem for multiple reasons like higher speed, better climb rate, reliability, cost, ease of ...
5 votes
4 answers
5k views

Did WW2-era aircraft have constant-speed or variable-pitch props?

This is slightly related to my other question on variable-pitch controls. I want to know if WW2-era aircraft typically had variable-pitch or constant-speed propellers. Variable-pitch lets the pilot ...
2 votes
1 answer
147 views

How do I get rated to fly complex aircraft that are still Microlights?

In the most recent issue of the BMAA magazine, there are new aircraft listed that are still Microlights, but have complex features. These include Autopilot(!), retractable landing gears and even ...
2 votes
1 answer
228 views

What would have been the pitch angle of this McCauley Prop before impact?

I'm trying to determine the pre-impact pitch of a two blade McCauley variable pitch on a Cessna 210 that hit shallow ocean water (8 feet, mostly sand) shortly after takeoff from an altitude of 300 ...
7 votes
3 answers
557 views

What would happen if the blades of a variable pitch prop did not all have the same pitch?

What would happen if one or more of the blades (but not all) on a variable pitch prop would not tilt at the same angle as the other ones? Could this situation happen or is the technology so advanced ...
4 votes
1 answer
2k views

What is the force to change the pitch of a variable pitch propeller?

At the moment I am struggling with the problem that I do have an idea how to calculate this force by using the blade element theory and going over a whole propeller blade in order to calculate the ...
0 votes
0 answers
114 views

where is the centrifugal force the flyweights experience coming from?

The T6b uses a PT6-68 engine which has a variable pitch, constant speed, feather, and non-reversible prop system. There is only one lever in the cockpit which regulates Torque and the Power Management ...
21 votes
8 answers
5k views

Variable pitch propellers: Why are they constant speed too?

I am studying for my PPL, and after going through aerofoils, lift, drag, optimal L/D ratio, propeller blades and the like, the need for a variable pitch propeller is absolutely clear to me. It is also ...
3 votes
2 answers
3k views

Why, with a constant speed propeller, does moving the propeller control forward increase drag?

Could someone explain why, let's say in a constant speed propeller, with moving propeller control forward the drag increases? It is noticeable when we push the blue knobs forward in flight that the ...
3 votes
2 answers
7k views

Why does a low pitch propeller have better acceleration/take-off and climb characteristics than a high pitch propeller?

Why does a propeller with a low pitch have better acceleration/take-off and climb characteristics vs. a high pitch propeller? And conversely, why is a propeller with a high pitch not as good during a ...
5 votes
2 answers
2k views

How will a variable pitch propeller move during takeoff?

In my ATPL books i've learned that for a variable pitch propeller, it is better to have a fine pitch for take-off (higher RPM) and a coarse pitch for cruise (lower RPM). In this question taken from ...
5 votes
6 answers
2k views

What other advantage(s) does an adjustable prop give you?

From what I understand, the purpose of a variable-pitch propeller (be it manually adjustable, or constant speed) is that it allows the engine to always operate at its most efficient speed, much like ...
7 votes
1 answer
926 views

How will the Rolls Royce UltraFan provide reverse thrust?

When perusing the Wikipedia article on the upcoming Rolls Royce UltraFan engine, I noticed that it cited an interesting bit of information from an Aviation Week article: As the fan system is ...
1 vote
1 answer
1k views

What is the relationship between speed, torque and pitch in a helicopter?

Can someone clarify the relationship between aircraft speed, torque, prop length and pitch and how this applies to a helicopter. In addition I want to know if the amount of lift a helicopter ...
3 votes
1 answer
10k views

Difference between constant speed and variable pitch propellers?

Here is how I currently understand constant speed and variable pitch propellers. In constant speed propellers, the pilot controls the governor via the prop control knob and the speeder spring, ...
2 votes
3 answers
2k views

Is the purpose of variable pitch propellers to maintain an optimal angle of attack?

I recently had a discussion with an aviation expert, who works as a Flight Instructor, about constant speed propellers - variable pitch propellers - on light piston aircraft. I have always known that ...
1 vote
0 answers
85 views

How to compute actuator torque requirement for Variable pitch mechanism??

Suggest me any reference to compute the torque requirement for actuator/motor to control the pitch angle of propeller (Variable Pitch Propeller). Thanks in advance Arun Ravindran
2 votes
1 answer
730 views

How did the controls work for variable-pitch props?

Variable-pitch propellers date way back to the 1930's and even earlier. I would like to know, what kind of controls they used? Some kind of lever or crank? How heavy were these controls? I'm thinking ...
2 votes
0 answers
374 views

What calculations are needed for counter-weight balancing on a propeller?

I am designing a small-scale propeller and i have managed to design on optimized geometry for the blade. However the blade pitch angle adjusts according to different flow speeds so i need to mount ...
7 votes
3 answers
4k views

In a constant speed propeller, why does the RPM drop with a prop pitch increase?

When a constant speed propeller changes its pitch from low to high, RPM would decrease. Why is that the case? Wouldn't the RPM increase when we increase the blade angle since there's less drag and ...
0 votes
1 answer
1k views

How to find trim condition of a sectional airfoil without knowing the angle of attack?

I am using a reflexed airfoil designed for positive pitching moments to achieve a pitching angle matched to the changing of free-stream velocity (Aerodynamically tailored). I ended up with a pitching ...
0 votes
0 answers
512 views

How to define pitch angle for a passive variable pitch propeller?

This question is a continuation of the question How to calculate variable pitch propeller parameters? mentioned before. Actually, the theory described as an answer on the question above is the exact ...