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Questions tagged [propeller]

Aircraft propellers are airfoils which convert rotary motion from a piston or turbine engine into thrust suitable for propelling an aircraft.

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What causes these losses in this propeller simulation?

While running a CFD simulation comparison of 2 vs 3 blade propeller versions (48" diameter, 23" pitch, 3570RPM), I've come up with: 2-blade: 347N of static thrust @ 110Nm Torque 3-blade: 220N of ...
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1answer
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How do blade cuffs help cool the engine?

How does the blade cuff (a fairing of suitable airfoil shape used to cover the shanks of propeller blades in order to reduce the aerodynamic losses) help cool the engine?
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1answer
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What happens when a propeller is placed in beta while feathered?

Could someone explain beta range to me? What happens when we set the throttle control lever to the beta range (reverse thrust) while the propeller blades are in the feathered position? Will the ...
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2answers
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Do jet aircraft have an emergency propeller?

I once heard, or misheard, this: There is an emergency propeller that comes down in an emergency of jet-engine aircraft. It is behind the main landing gears. Is this true or a story somebody made ...
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3answers
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How does the relative wind on a propeller, strike the blade from behind (the non camber side)?

This may be a stupid or simple question, although any help is appreciated! :) If possible, please answer without mathematical terminology. So I understand the concept of the blade increasing air ...
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1answer
350 views

Rotation direction for adjacent propellers, how do different arrangements compare?

(YouTube) The Airbus A400M uses counter-rotating pairs where the blades meet moving downward (if there is a better description, tell me please). I played the video frame-by-frame to make sure it ...
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4answers
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Why do solar planes have many small propellers instead of fewer large ones?

Many solar planes, like NASA's Helios (pictured above), NASA's Pathfinder, and to a lesser extent Facebook's Aquila employ the use of many small motor propeller sets instead of one or two engines like ...
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570 views

why are airplane propellers always undersized?

While calculating propeller static thrust by using a famous Prop-power-calculator.xls (by Pé Reivers), I've noticed that no matter what "stock" configuration I put into the calculator, I do always get ...
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2answers
184 views

Feasibility of using secondary props to generate power on an electric model aircraft [duplicate]

Beginning with the aeroplane itself, it is a small, fixed wing model aeroplane, reminiscent design-wise to a Cessna 172. It is completely battery powered and has a primary prop attached to a motor ...
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4answers
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Why did WWII prop aircraft have colored prop tips?

Why do propeller aircraft from World War II and similar planes sometimes have the tips of the props colored? I see it on single engine planes like the P-51 as well as bigger, multi-engine planes such ...
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3answers
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Why doesn't a single engine airplane rotate along the longitudinal axis? [duplicate]

As far as I know, the tail rotor in helicopters prevents the aircraft from turning in the opposite direction that the main blades turn (due to Newton's third law). On the other hand, torque in single-...
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1answer
1k views

Quadcopter propeller performance [closed]

Quadcopters use both direct and contra-rotating propellers to be able to turn and to balance the torque caused by the each of the propellers. Propeller performance measurement: When testing the ...
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1answer
311 views

Why do these tail-sitters not have bigger propellers in their main engine?

My attention was called to tail-sitter aircraft, like these two: Convair XFV Pogo By No information - US Navy, Public Domain, Link Lockheed XFV 1 Public Domain, Link These aircraft land on their ...
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198 views

What is the history of this specific Cessna propeller (s/n F2430)?

Hoping someone can help... I'm looking to get some information about a Cessna plane propeller my Fiancé recently bought. It's his birthday coming up and it would be great to have any sort of history, ...
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2answers
829 views

How to design a propeller for UAV?

I need some advice on designing a propeller for a UAV and choosing the right motor for it. I am doing a project which requires the fix-wing UAV to travel at cruise speed of 20 m/s and weighs a total ...
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4answers
797 views

In general terms, is a Constant Speed Propellor equiped aircraft more expensive to maintain?

I've been looking at possibly buying a used Mooney M20 or a used Cessna 172. One of the big differences between the two is that the Cessna is a fixed prop, and the Mooney is a constant speed ...
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188 views

What are the most number of propellors that a rotorcraft has been flown with?

If you had 1000 small propellors you could accelerate upwards many times faster than with 4 large propellors. What are the rotorcraft experiments with the most number of propellors ever?
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What are the main differences between scimitar and regular propellers?

I am looking to know the main differences between scimitar and regular propellers. Can somebody help me on this?
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1answer
2k views

What is autofeather for?

What is autofeather and when is it used?
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2answers
312 views

Why are commercial propeller aircraft smaller than commercial jet aircraft? [duplicate]

I've read that turbo-prop aircraft are more efficient than jet-aircraft. Browsing this Wikipedia page it looks like in general, jet airliners burn less fuel per passenger. I imagine this is due to jet ...
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2answers
271 views

Is there really anything to be gained by placing the propeller at the top of the vertical stabiliser?

I am currently designing an electrically powered RC plane with one propeller. The wingspan is c. 2.5 m and the length c. 1.6 m. Right now the plan is to put the propeller at the top of the VS where ...
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289 views

Can quadcopter-like UAVs ever get significantly quieter? Any candidate technology?

The light weight quadcopter and hexacopter UAVs that can cary say 2kg to 20kg payloads for "delivery" produce enough noise that a steady stream of pizza and book deliveries might not be so welcome in ...
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Why does the spiraling slipstream from a propeller hit the left side of the fin?

In the picture below, if the fuselage was shorter/longer, would the spiraling slipstream from a propeller hit the fin on the right side as opposed to the left? Is it a deliberate positioning if yes, ...
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4answers
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Why do ground crews rotate a radial engine's propeller before a motor/cartridge start?

In footage from WWII you often see the ground crew rotating the propeller of a radial engine a number of times before the pilots start the engine. I know it's not the same as hand-starting (hand-...
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2answers
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Why do most propeller-powered planes not have an autothrottle?

Why does every kind of propeller-powered plane lack an auto-throttle? No single-props no twin-props, not even turboprops like the Dash-8 Q400. To be honest, I don't know many turboprops, but if the ...
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2answers
586 views

How much could human power add to the endurance of an electric gyrocopter?

If we take a single seater electric gyrocopter like this one, could a human-powered propeller like this add to the endurance of the aircraft? The gyrocopter only needs a 32km/h forward speed to stay ...
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1answer
456 views

How can I scale down a propeller for wind tunnel testing?

I want to scale down my propeller for a wind tunnel testing. But I am unable to find any literature on it. Please give suggestions.
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How can I use electric motor data with my prop data to obtain a power available verses velocity curve?

I'm not entirely sure this is appropriate for this forum but it's worth a shot... I have propeller data ($C_T$ , $C_P$ , J , and $\eta$) and very very limited electric brushless motor data (motor ...
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1answer
909 views

What is the equation for the energy balance between turbine, compressor and propeller?

Let's consider the next turboprop arrangement: What I am looking for I am looking for an equation that involves $\dot{W}_T$, $\dot{W}_C$ and $\dot{W}_P$ (i.e. the power done by each component). This ...
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2answers
4k views

What are the pros and cons of scimitar propellers?

I know scimitar propellers are used to reduce noise, but what is their downside? There has to be one, considering most propellers don't use that shape.
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2answers
18k views

Are ducted fans more efficient?

As far as static thrust, does a shrouded/ducted propeller outperform an un-shrouded propeller? It seems that the guide blades on the bottom of the duct would allow little more thrust to be extracted ...
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1answer
212 views

How does the performance of an aircrafts propeller change with respect to distance from obstructions?

I am interested to know if there are any changes in propeller performance (thrust, efficiency) with respect to distance from obstructions such as the fuselage or wings? I am particularly looking for ...
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1answer
249 views

Do propellers have any lead/lag mechanism?

The fan blades in a fanjet are mounted loosely in a fir-tree shaped mount so they are free to lead or lag and balance themselves. The blades on fully articulated and semi-rigid helicopter rotor heads ...
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3answers
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Can jet engines be used for VTOL civilian aircraft?

Why do almost all civilian VTOL aircraft existing today use propellers (or rotors) for take off and landing and not jet engines (as the Harrier does)? Is there a technical reason for this?
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How does a fan differ from a propeller?

Why is the fan in a turbofan different than a propeller in a small airplane? Why do propellers typically have 2 or 3 blades, but the fan has a lot more? And why is the fan shrouded but the propeller ...
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1answer
351 views

What is the Effect of Unsynchronized Propellers?

A long time ago, I had the privilege of flying in 4 engine turboprop airplanes in which the props were 'synched'(blades rotating in same speed) which of course is necessary for smooth thrust. However,...
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1answer
240 views

How is propeller thrust vector accurately expressed for airplanes and multirotors? [closed]

For propellers, as the airspeed increases thrust decreases. Is the airspeed component taken as a vector quantity perpendicular to the propeller? If that's true, then it's quite easy to visualize in ...
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1answer
321 views

Propeller Torque [duplicate]

We know that every rotating device generates torque . How does a single engine propeller A/C (Piper) counter-balance the torque which is being produced by nose propeller?
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772 views

Has the United States Air Force used Contra-rotating Propeller Aircraft?

I recently saw a picture of a Russian Bear(TU-95) intercepting one of our(US) military aircraft over the Pacific Ocean. Many years ago, when I flew in reconnaissance aircraft, we were frequently ...
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2answers
4k views

Which way should I rotate the propeller of a C172?

During pre-flight which direction should I be rotating the propeller of a Cessna 172 if I need to reach the alternator belt? I thought I was told "In the direction it rotates during flight"; however ...
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0answers
126 views

How far ahead of the wing should a propeller be located for a UAV? [closed]

This question is asked in context of a fixed wing, Unmanned Aerial Vehicle (UAV), with a wing span of about 5m (16ft). How far ahead of the wing leading edge should the propeller be located? The ...
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2answers
1k views

Can noise from contra-rotating propellers be reduced by having a different number of blades on each propeller?

Heads up: This came from Wikipedia's page on contra-rotating propellers and it explicitly says citation needed: However they can be very noisy ... It is also helpful if the two propellers have a ...
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2answers
148 views

Can the measured thrust of a propeller be greater than the max thrust predicted by Froude's theory?

Can the measured thrust of a propeller be greater than the maximum possible thrust predicted by Froude's Propeller Theory? Is Froude's theory reliable in practice regarding the upper limit of the ...
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3answers
1k views

Is it possible to tilt a propeller for attitude control, similarly to jet thrust vectoring?

Are there examples of propellers tilted in a controlled way to help in attitude control for pitch and yaw, adding a torque component? Tilted propeller assumption This would be similar to thrust ...
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1answer
7k views

What is the correct formula to calculate propeller efficiency?

How to calculate in the right way the efficiency of a propeller? If we know the engine power, speed of the plane and the thrust of its propeller, what is the correct method, (1) or (2), for ...
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What was the exact propeller geometry of the 1903 Wright Flyer? A modern replica failed the test T = D in a NASA wind tunnel [closed]

Full-Scale 1903 Wright Flyer failed the test Thrust = Drag in a NASA wind tunnel I have found a presentation about an extensive set of tests done in 1999 on a full scale replica of Flyer I 1903. The ...
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1answer
208 views

Looking for the correct propeller shape to create a small copter [duplicate]

I am trying to create a mini flying quadrocopter using a Raspberry Pi (mini programmable computer). So far I have hooked up the RPi to 4 motors with controls to each. I'm pretty happy with that side ...
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1answer
1k views

Rings around propellers [duplicate]

As a followup to Why do turbofan blade tips exceed the speed of sounds while prop tips should not my question is: why have rings on propellers not been used to overcome this problem? It seems from ...
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3answers
1k views

How critical is it if a pebble blows into a propeller?

How critical is it if a pebble blows into a propeller while taxiing and leaves a small abrasion in the leading edge? It wasn't noticed during flight and there was no apparent change in performance of ...
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2answers
2k views

How can an airplane fly with single propeller without rolling over? [duplicate]

I have no knowledge about aviation or mechanics or something. Recently I started a computer game 'besiege', a kind of sandbox-like game with bunch of parts to make all kinds of machinery. And I'm ...