PropCalc computes the performance data of propellers with a given geometry, notably in-flight thrust and power drain across the utilizable airspeed range. PropCalc comes with a database that contains the polars of current airfoils as well as geometrical data of a number of propellers. The user may amend and enlarge the database. All data are editable, so that PropCalc may be utilized as well for designing propellers. Select a propeller from the popup menu list in the main application window.
Holding the left mouse button and dragging the mouse cursor vertically anywhere in the graph area will also change the rpm setting. PropCalc computes the results that are displayed in the graphs for the defined rpm over the course of the airspeed, or the rate of advance, respectively, up to the point at which the thrust fades.
You may take each of the small graphs to the front, that is have it displayed large-sized, by clicking on it. By clicking on the button 'Result Table' you may open a window that displays the results in the numerical form. The result table can be saved to a 'character separated values' file. If needed, you may modify the decimal separator and the field delimiter used in the. To inspect the propeller data, modify the selected propeller, or enter new propeller data, select 'Propeller' in the application's 'Edit' menu, or double-click on the airfoil drawing in the main window.
This will open the propeller window. In the propeller window you may enter or change the propeller's geometry. You may as well select a different airfoil and thus change the propeller's properties.
The result of any modification will immediately show up in the diagrams in the main window. The original data supplied in the database will remain unchanged unless you explicitly order to have the modified data written into the database by clicking on the 'Save' button.
Before experimenting with the propeller data it is a good idea to make a copy of the propeller so as not to lose or change the original data accidentally. The contents are copied to a new record and the word "copy" is appended to the propeller's name.
Geometry for the Design of Wageningen B-Series Propellers
When entering new data, use a unique name, so that the propeller can be identified in the popup menu lists. If the diameter is changed, all dimensions will be converted accordingly. This will make up a bigger or a smaller propeller of the same shape. The blade's chord and angle measured underneath the blade are defined by nine measurement points along the radius.
By varying the chord factor you can examine the effect of different chord sizes on the propeller's performance. You may also enter a blade angle adjust value, thereby skewing the blade and thus changing the pitch within certain limits. The propeller blade drawing on the right side shows the chord and the blade angle over the course of the radius.Various propeller and rudder types are used in different ships; all for the same purpose to steer and propel the ship.
A propeller is a big fan like structure that rotates to provide required thrust to move the ship; while a rudder is an flat piece of metal at the stern of the ship to steer. In the first half of the article, we will discuss about propeller, its geometry, types, efficiency and its maintenance. While on the second half we will learn about rudders, its types and use on ship. A propeller is a mechanical device with blades that spins around a shaft to produce necessary thrust to propel the ship.
The propulsion system with shaft, engine and propeller moves the ship based on newtons third law of motion. The propeller push the water backwards while the water around push the ship forward with equal force. No matter how much development has happened in propeller geometry. Today a conventional propeller is still the sole force of ship propulsion.
Nowadays a ship can have one two or even three propellers not just in numbers but types too. It depends upon the needs for speed, power, draft and efficiency of the ship. Marine propellers are made of anti corrosive materials such as aluminum bronze or manganese bronze alloys to avoid corrosive conditions at sea. Apart from them; alloys of stainless steel and nickel are also used to construct marine propellers.
Generally aluminum-bronze alloy is preferred over others due to its light weight and good strength. A typical propeller is made up of Nikalium Aluminum-Bronze and have elements in composition; Aluminum 9.
Propeller Construction, Geometry, Working And Rudder
A propeller is constructed by adding blades to the hub. A forged construction is reliable and have better strength but avoided due to high cost.
Before understanding propeller types, working and efficiency we must understand basic points of propeller geometry. The key points of propeller geometry are A solid circular disc at the center which holds the blades and mate with the shaft. Smaller the diameter, higher is the thrust produced with lesser strength.Lecture 19 - propeller Theories
So a optimum diameter is chosen to get the maximum thrust at maximum possible strength. These are the twisted fins like structure attached to the propeller hub. The torque produced by a ship propeller depends upon the shape and driven speed of these blades. The front side of the blade that faces aft towards ocean when the ship moves forward.
This is what that pushes the water backward to create necessary equal and opposite force to push the ship forward. The part of propeller blades that is attached to the hub is called blade root while the farthest point on the blade edge is called Tip. The side of blade that cuts through the water is known as leading edge; while the other side is called Trailing edge.
Larger the diameter higher is the thrust produced with better propeller efficiency. But after certain point increasing diameter can increase unwanted propeller drag. It is the number of revolution that a propeller made during an interval of one minute.
Generally on cargo ships; propeller with low RPM and bigger diameter is chosen for higher thrust with better efficiency. On the other hand, high speed vessels that require much less thrust; need smaller diameter with high RPM propeller for better efficiency. It is the imaginary distance the propeller would move forward on shaft in one revolution.
I called it imaginary distance as the propeller never moves forward on shaft; instead push the water backwards. So if a propeller has a nominal pitch of 20 inch; it indicates that it would have moved Imaginary to inch on shaft in one revolution. And the distance between this imaginary distance and actual displacement of ship is called slip.The online apps on this website allow you to quickly generate high-quality CAD geometry for the B-series propeller.
You have two choices: A preliminary design tool and, further down this page, a direct geometry generator for advanced controls. We do the calculation to find a suitable propeller shape that fits your requirements — in just a few seconds.
Do you already know your geometrical blade parameters values such as pitch, rake, thickness, diameters etc.? Then try out the fast blade geometry generator, which gives you direct and accurate shape control! The 2D profiles of the generated propeller are very close to the B-Series definitions.
However, some deviations are possible with regards to the original B-Series due to modifications we apply if we consider it as required and practical.
In addition, we recommend that a thorough engineering study be conducted before the generated geometry is used. Note that both online apps require the use of e. Chrome or Firefox browser. There are known issues with the Internet Explorer.
We are happy to receive your feedback. If you have any input or questions for us, or if you need a special propeller design that is not covered by this propeller generator, then please do not hesitate to get in touch with us. Your Name. Your E-Mail. Your Comments. Your fast and simple online tool for solid propeller geometry. Enter your information about the ship and the propulsion system. Check the visualization of the propeller.
Fast Geometry Generator Do you already know your geometrical blade parameters values such as pitch, rake, thickness, diameters etc.? How do you like the propeller tools?
Please rate by clicking on the stars:.This webpage includes wind tunnel measurements for nearly propellers used on small UAVs and model aircraft. The propellers were purchased off-the-shelf from retail outlets and were unmodified for these tests.
Measurements include thrust and torque coefficient data over a range of advance ratios for specific RPMs. Also measurements were taken in static conditions for a sweep over RPMs. Some of the propellers have been digitized approximately and these data are included below. References  Brandt, J. Notes The propeller size is given in inches, e. APC 10x4. The four digit numbers below in the 'Data' category represent the propeller RPM values of each run.
A wind tunnel correction method for the drag due to the propeller mounting fixture is outlined here. This means that these online data should be used and not the tabulated and plotted data taken directly from Ref 1. Nevertheless, Ref 1 includes a detailed description of the test methodology, and it is can be downloaded here.
The power coefficient data below were obtained from the measured torque coefficient and advance ratio. Aeronaut Carbon Electric 8. APC Carbon Fiber 7.The computer program is based on the formulas presented in [ 10 ] comparison Adkins vs. Based on the theory of the optimum propeller as developed by Betz, Prandtl, Glauertonly a small number of design parameters must be specified. The design procedure creates the blade geometry in terms of the chord distribution along the radius as well as the distribution of the blade angle.
When you look at the resulting geometry, you might understand why highly efficient propellers for man powered aircraft, indoor free flight models or FAI-F1B rubber powered models look as they look like. The local chord length c depends mainly on the prescribed lift coefficient Cl - if you would like to have wider blades, you have to chose a smaller design lift coefficient resp.
It should be noted, that the design procedure does not work accurately for high thrust loadings as they occur under static conditions. If you receive nonsense values for the blade chord, the power loading of the propeller is probably too high. Check if the power coefficient Pc is less that 1.
The number of blades has a small effect on the efficiency only. Usually a propeller with more blades will perform slightly better, as it distributes its power and thrust more evenly in its wake.
But for a given power or thrust, more blades also mean more narrow blades with reduced chord length, so practical limits have to be considered here. The chord length can be increased while decreasing the diameter to keep the power consumption constant, but a diameter reduction is usually a bad idea in terms of efficiency, as long as the tip mach number or tip cavitation is not an issue.
The velocity of the incoming fluid together with the velocity of rotation r. Large pitch propellers may have a good efficiency in their design point, but may run into trouble when the have to operate at axial velocity. In this case, the blades tend to stall. The propeller diameter has a big impact on performance. Usually a larger propeller will have a higher efficiency, as it catches more incoming fluid and distributes its power and thrust on a larger fluid volume.
The same effect can be shown for lifting surfaces, which results in sailplanes having large span but slender wings. Instead of the lift and drag coefficients, it usually convenient to specify an airfoil with a prescribed polar and the design angle of attack at each radius. In JavaPropdefinition sections are spread along the radius where airfoil and the design angle of attack can be prescribed.Blade Element Propeller Theory.
A relatively simple method of predicting the performance of a propeller as well as fans or windmills is the use of Blade Element Theory. In this method the propeller is divided into a number of independent sections along the length. At each section a force balance is applied involving 2D section lift and drag with the thrust and torque produced by the section.
At the same time a balance of axial and angular momentum is applied. This produces a set of non-linear equations that can be solved by iteration for each blade section. The resulting values of section thrust and torque can be summed to predict the overall performance of the propeller. The theory does not include secondary effects such as 3-D flow velocities induced on the propeller by the shed tip vortex or radial components of flow induced by angular acceleration due to the rotation of the propeller.
Some of the flow assumptions made also breakdown for extreme conditions when the flow on the blade becomes stalled or there is a significant proportion of the propeller blade in windmilling configuration while other parts are still thrust producing.
The theory has been found very useful for comparative studies such as optimising blade pitch setting for a given cruise speed or in determining the optimum blade solidity for a propeller.
Given the above limitations it is still the best tool available for getting good first order predictions of thrust, torque and efficiency for propellers under a large range of operating conditions. V 1 -- section local flow velocity vector, summation of vectors V 0 and V 2. Lift and drag of the section can be calculated using standard 2-D aerofoil properties.
Note: propellers use a changed reference line : zero lift line not section chord line. The lift and drag components normal to and parallel to the propeller disk can be calculated so that the contribution to thrust and torque of the compete propeller from this single element can be found.
A major complexity in applying this theory arises when trying to determine the magnitude of the two flow components V 0 and V 2. To calculate V 0 and V 2 accurately both axial and angular momentum balances must be applied to predict the induced flow effects on a given blade element. As shown in the following diagram, the induced components can be defined as factors increasing or decreasing the major flow components.
A typical streamtube of flow passing through section AA would have velocities.
So for the velocities V 0 and V 2 as shown in the previous section flow diagram. The governing principle of conservation of flow momentum can be applied for both axial and circumferential directions. For the axial direction, the change in flow momentum along a stream-tube starting upstream, passing through the propeller at section AA and then moving off into the slipstream, must equal the thrust produced by this element of the blade.The software is specifically tailored for model and UAV propeller design and manufacture.
This system has been undergoing continuous development and improvement for over two decades. APC propellers are injection molded using a pair of mold halves. CNC milling machines are used to create the molds.
The design of the computer software used to define airfoils, and the resulting CNC motion, dominantly reflects parting line driven requirements. The parting line must be very precise and continuous around the entire perimeter of the mold cavity to allow precision molding of the very thin airfoils used on many of the APC propellers.
The airfoils may have arbitrary shapes defined with either tabular data splined cubic fits or analytical functions typically used for NACA airfoils. The airfoil shapes may vary with span. Capability exists to smoothly "splice" together widely different airfoil shapes. The dominant basis for the primary airfoil shape used in most APC propellers is similar to the NACA and Clark-Y airfoils, except the leading edge is somewhat lower.
Also, the aft region is somewhat thicker. This alters the zero-lift angle by approximately one degree and provides greater lift without having to twist the blade more. Most blades have some washout near the tip. For applications where Mach number effects become significant near the tip, either pitch washout or camber reduction are used to minimize Mach drag rise. Thin electric, slow-fly, and multi-rotor propellers typically blend the low Reynolds number Eppler E63 airfoil inboard with a Clark-Y similar airfoil near the tip.
Cross-section geometry in and near the hub region is defined with specialized algorithms. The aerodynamic-dominant airfoil must smoothly transition into a structural-dominant shape in a manner that emphasizes strength consistent with milling machine tool constraints. Hub geometry for 3 and 4 bladed propellers is very complex because of the need to match mold parting lines at all points on the mold surface perimeter.
Vortex theory is the basis for the computational method used to calculate blade loading. For some applications, i.
These flow field effects are computed using 3D potential flow theory. Empirical data are used to characterize minimum drag levels under low propeller loading conditions. The TAIR code is most appropriate for high speed conditions. This code has been heavily developed to provide very stable numerical performance over a broad range of environments. Stability is an essential property for batch processing described below. APC is currently developing the ability to analyze airfoils at slower speed conditions within our design software.
We expect that this improvement will substantially increase predictive accuracy of performance data at low Reynolds numbers. APC provides Performance Data files for all propellers currently in production.
These performance data provide estimates of thrust, torque and efficiency over a broad range of model speeds and engine RPM.