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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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-1 votes
1 answer
120 views

How many ways/methods to calculate propeller/rotor's power output? Which one is the best?

Source: Wikipedia I want to know how many ways/methods to calculate the output power of a propeller? So far I knew three methods: Momentum Theory (MT), Blade Element Theory (BET), Blade Element ...
5 votes
2 answers
725 views

Are narrow propellers more efficient than wider ones?

I came across this company E-Props that builds propellers and it seems like all their propellers are narrower, at least narrower than traditional ones I'm used to see, and I see on their picture ...
1 vote
2 answers
117 views

Propeller Torque Calculation

Propeller torque is given as $Torque = c_p * ρ * (\frac{ω}{2π})^2 * d_p^5$, where $c_p$ is the torque coefficient, ρ is the air density, ω is the angular velocity, and d is the propeller diameter. I ...
2 votes
0 answers
49 views

Is there a convention of propeller tip separation from the wind tunnel walls?

Blockage ratio is commonly used to address the effect of confinement on the propeller's performance tested inside a closed test section of a wind tunnel. In most cases, blockage corrections (like ...
5 votes
2 answers
202 views

Could a propeller system for airplanes with automatic, cyclic blade-pitch control that is designed to counter p-factor be practical?

Considering that P-factor is a result of differing angles of attack of the blades on an airplane's propeller, I would imagine that if there was a design that could control the pitch of each individual ...
7 votes
2 answers
598 views

How to calculate velocity of air behind a propeller?

Background: I came across this article by Gabriel Staples to calculate static and dynamic thrust of a propeller. In the derivation, it was assumed that the exit velocity is equal to the pitch speed of ...
0 votes
1 answer
121 views

Three-blade propeller balancing

I'm balancing a three-blade propeller. The propellers weigh exactly the same to the 10th of a gram. When I place it on shaft with a very sensitive wheel bearing, one of the blades always moved ...
1 vote
1 answer
68 views

McCauley propeller models IC235/LFA7570 and IA170E/JHA7660

I am writing to inquire about the pitch specifications for the following McCauley propeller models: IC235/LFA7570 with a maximum diameter of 75 inches and minimum diameter of 74 inches. IA170E/...
5 votes
3 answers
142 views

How can I find the minimum and maximum airspeeds for efficiency with a specific prop/engine combination?

I'm operating a Cessna 180 with various wing and weight mods with a TCM IO550D engine and a McCauley Black Mac (D3A34C401/90DFA-2 3 blade (88 inch) seaplane prop. I operate Lean of Peak (LOP) for most ...
1 vote
0 answers
76 views

Could a WW2-era Grumman Hellcat land on a Saipan-class light carrier using only reverse-thrust generated by a reverse-pitch propeller?

Just that - take away an F6F's arrestor hook and fit it with a reverse-pitch-capable propeller (and, of course, all the other odds-and-ends to make such a system work). Would it be possible for a ...
2 votes
1 answer
149 views

How to design a propeller that works efficiently in reverse?

I'm designing a UAV that needs to reverse motors for some maneuvers, but unfortunately most of the commercially available propellers I've tested are optimized for single direction and only produce ...
2 votes
2 answers
181 views

Determining Sectional Drag Coefficient Using Propeller Geometry

Im trying to teach myself blade element theory for helicopters and propellers, but im getting quite confused. Most of the papers and textbooks I read will reach an equation for differential thrust ...
10 votes
2 answers
796 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 ...
3 votes
1 answer
170 views

Is the math behind my approach to design a propeller right?

I'm trying to design a fixed pitch propeller of diameter 1.8 m flying at 10000 ft going at forward velocity(85 m/s). What I've done is take a series of airfoils (from root to tip), found the ...
3 votes
1 answer
178 views

Where does "wasted" propeller power go?

Aircraft propellers are very efficient, with around 80-90% of input horsepower being applied to axial flow. However, that raises the question of where the remaining 10-20% of energy goes. I'm ...
0 votes
0 answers
54 views

How can I cross verify my propeller thrust? [duplicate]

I'm simulating a propeller in Ansys and im getting a thrust of 2000N. The forward speed is 85m/s and 240.25 rad/s angular velocity and the diameter of the propeller is 1.8m. Since I'm not able to find ...
3 votes
2 answers
7k views

How does the location of a propeller affect an aircraft's stability?

Some aircraft possess propellers on front of the fuselage, like the Cessna 172, and some aircraft have propellers located at the rear of the fuselage, like the Velocity 173RG-E. How does the ...
0 votes
0 answers
31 views

how can we calculate normal force or vertical component of propeller in an aircraft?

when we calculate thrust of an propeller engine we also face to vertical component or normal force which change neutral point of an aircraft how can we calculate this force? thank you
3 votes
2 answers
271 views

What's the thrust of a given propeller at zero airspeed?

If memory serves correctly, propeller thrust for a given propulsive horsepower is inversely proportional to airspeed, assuming features like constant RPM prop, and being outside Mach Effects The ...
1 vote
0 answers
61 views

How to retrieve the thrust distribution over a blade using XROTOR?

What is the procedure for retrieving the thrust distribution over a propeller blade using XROTOR? I need the sectional (i.e., for each station) thrust coefficient values. I was only able to retrieve ...
2 votes
1 answer
137 views

When discussing a “feathering, counterweighted propeller” where are the counterweights?

We are learning about propellers in school. To my understanding, generally a non-feathering, non counterweighted prop uses centrifugal twisting moments to lower blade pitch while oil pressure is used ...
3 votes
4 answers
525 views

Could a quadcopter fly if its propellers were encased in cylindrical tubes?

Picture a standard quadcopter, with regular old propeller guards, which are generally just circles around the propellers. Now, take the propeller guards and stretch them so that they're cylinders ...
3 votes
1 answer
104 views

What does "Rotating airfoils of engines" mean in the US Code of Federal Aviation Regulations?

In part 1.1 of the US 14 CFR, definitions and abbreviations, a propeller is defined as: ...a device for propelling an aircraft that has blades on an engine-driven shaft and that, when rotated, ...
1 vote
3 answers
2k views

Propeller Characteristics at Different Altitudes

Assuming I have a propeller with a given diameter (D), pitch, blade twist, and number of blades, I can theoretically analyze discrete airfoil sections in XFOIL and come up with lift and drag polars ...
2 votes
1 answer
178 views

Is there a standard way to identify propeller blades?

Obviously, as Julio pointed out, Chuck's method of identifying propeller blades is ineffective. Is there a standard way to identify blades, other than tautological statements like "There is a ...
0 votes
2 answers
212 views

Does propeller width have a material impact on thrust? [closed]

I have seen propeller thrust calculations and they do not appear to have the variable of propeller width. They only use diameter or radius. What if any impact does width of the propeller have? Here is ...
2 votes
2 answers
8k views

How does Propeller windmilling work?

I’ve got a problem with understanding propeller windmilling. What I know is that when rpm are low and tas is high the blade aoa goes „over” the blade and is some kind of negative now, producing thrust ...
0 votes
1 answer
157 views

Hypothesis: swept back propeller would reduce drag and increase thrust [duplicate]

Hypothesis: swept back propeller would reduce drag and increase thrust. Any experience with this?
0 votes
0 answers
113 views

Deriving Accurate Exit air velocity of rotor

My goal is to derive the equation for exit air velocity as a function of: Pitch angle RPM Rotor Radius Constants like ρ Assumptions: Vc is relative velocity of air upstream, and is = 0 Inflow is ...
2 votes
5 answers
683 views

Can an airplane propeller become supersonic?

Is it possible for an aircraft propeller to become supersonic? I am not referring as for the aircraft, only the rotating blade. I know it is extremely unlikely for a propeller plane to go supersonic, ...
-1 votes
1 answer
399 views

What velocity is used to calculate maximum range and maximum endurance?

These are my data; $C_{L_0} = 0.4$ $C_{L_{\alpha}} = 5.7$ $C_{L_{minD}} = 0.14$ $C_{D_{min}} = 0.022$ $k = 0.035$ $\alpha_{stall} = 15$ $S_{ref} = 20m^2$ Mass Data $W_{total} = 2500 \text{ kg}$ $W_{...
1 vote
1 answer
91 views

XRotor blade angle distribution

My question is about the XRotor definition of the blade angle distribution (beta), which XRotor solves for or requires as input. Is the blade angle on XRotor defined as the angle between the rotation ...
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
203 views

Do full-feathering constant-speed propellers have a high-pitch stop for the prop governor?

On full-feathering (hydraulic) constant speed propellers in general, and specifically Hartzell and McCauley props, does the propeller governor have a high-pitch stop (like non-feathering propellers, ...
54 votes
12 answers
123k views

Why are push-propellers so rare, yet they are still around?

Jet engines are by their very nature push-engines, however, most propeller airplanes use pull-engines. Is there an inherent advantage to using pull-propellers except for the increased airflow over the ...
1 vote
4 answers
275 views

Should I advance my propeller lever forward during a glide?

I am reading the FAA Airplane Flying Handbook, chapter 3. It says: To enter a glide, the pilot should close the throttle and, if equipped, advance the propeller lever forward. (...) Why do we ...
3 votes
3 answers
540 views

Cause of Drag From Windmilling

I know that when a propeller is windmilling it creates drag, I assume this is from the propeller being flat against the air causes drag, but propellers are designed to essentially pull an airplane ...
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 ...
2 votes
1 answer
199 views

Can a propeller with 90° pitching and symmetrical airfoils generate thrust?

Imagine we have a plane that is already moving at a speed $v_{plane}$. At a certain time $t=0$, a motor starts moving a propeller whose blades consist on symmetrical airfoils with $90^\circ$ of ...
2 votes
1 answer
180 views

Actual non-axial airflow (sideslip) for a propeller driven aircraft

I am making a propeller model for a two-engine propeller driven aircraft (like a Dornier 228). I have expanded my model to include the non-axial airflow as well. $$ $$ By non axial airflow, I mean ...
32 votes
2 answers
44k views

What are the advantages of more than 4 propeller blades?

I have heard that propellers with more than four blades are not as efficient as 4 or less blades because of lower thrust which may result from interfering prop-streams. But I see the ATR-42/72 and ...
24 votes
4 answers
20k views

What types of wood can be used for making propellers?

Early propellers were made from wood and they still are on some vintage/classic aircraft and reproductions. What types of wood are typically used to make wooden propellers?
2 votes
2 answers
9k views

How do I compute thrust of a rotor disk and the necessary power to drive it??

as it seems, this question has been asked a few times here so please forgive me for asking again. If I have 50 BHP shaft power available at 5000 RPM and 106 N.m torque, then can I convert it to 200 ...
1 vote
2 answers
138 views

Does the obstruction in a propeller duct increase exhaust pressure or decrease pressure/increase speed?

I came up with this question when looking through the answer for this question, which states that a convergent duct(obstruction) compresses the exhaust so that its pressure matches the ambient ...
8 votes
4 answers
4k views

Can you weld a propeller blade from 120 degrees to 180?

My uncle flew for Mission Aviation Fellowship (maf.org) for a university in Texas, and I believe that he was flying a Cessna to the Amazon (among other places). He actually knew Jim Elliot (who went ...
8 votes
1 answer
977 views

Are there any variable-diameter propellers?

Have there been any known tests or prototypes of variable-diameter propellers? There's this paywalled paper from 2014 that seems to have made a virtual prototype model, have there been any physical ...
6 votes
1 answer
262 views

Could floppy rotor blades be usable?

Autogyro and helicopter blades are more or less flexible, and when not stiffened by centrifugal force they droop noticeably. A extreme case would be that of fabric blades. They have been used at least ...
3 votes
1 answer
1k views

Do ducted fans have a future in forward flight aircraft? Can they be made more efficient than open rotors?

I'm fascinated by how ducted fans have the ability to be more efficient than open propellers of equal diameter in vertical flight through the use of tight tolerances, lightweight duct material, proper ...
14 votes
1 answer
2k views

What is this indication on most turboprops?

What is the small fan I've seen on different turboprops?

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