# Prop Diameter And Pitch Calculator

Estimated prop slip at required top speed. Beta 43 and PRM150 1:209 propeller size over reving its better to add pitch to a larger propeller and a 17. Marine propeller sizes are always specified by diameter and pitch (diameter x pitch) with the diameter dimension specified first. However, because boats vary widely due to a number of factors, it is not possible to guarantee which specific prop will perform best in any specific boating application. Directly Measure Roof Pitch Angle and Calculate Pitch and Angle on Phone or Tablet. Proper Pitch is a marine propeller and drive train facility, specialized in the sales and reconditioning of marine boat propellers and shafting. When it's time to purchase a new propeller, you have to be sure to buy one with the right pitch and diameter for the best performance. Propeller Selection. See the references for vendor link. If you want additional assistance from DUNNRITE PROPELLERS we will need to know in your e-mail, phone call, or fax: The make and size of your current propeller (Diameter & Pitch). If you have questions about the best boat props or propellers for sale for your motor, check on our Propeller FAQ's Page and have a look at the articles breaking down the factors surrounding your decision. An approximate relationship as a function of the number of blades is as follows: DN = 4 1 2 2 ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ Bn D DN is the diameter of a propeller of N blades D2 is the diameter of a two-bladed prop. Is the distance between propeller blade tips through the centre line of the propeller. - MT-Propeller - Fixed Pitch - Sensenich - 2 and 3 blade. In our case we went up to round the prop size so I will go down when selecting pitch size. 35mm diameter pitch 1. The stock propeller is an 11.
7 = Pp 6 x 0. You can change one parameter and recalculate the rest. For more information on propagations, visit the Propagation section on this site. An approximate relationship as a function of the number of blades is as follows: DN = 4 1 2 2 ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ Bn D DN is the diameter of a propeller of N blades D2 is the diameter of a two-bladed prop. Enter Base length to calculate Rise and Diagonal for current Pitch Angle. 5 HP 35 degrees, 14,700 CFM, 34 pounds, using 9. It was used on my 1985 endeavour 38 sailboat for approximately 20 years. You should be running a 14. (radius = diameter divided by 2) As most of this web site concentrates on smaller outboard and stern-drive propellers I'll just be talking about basic pitch measurements at the one diameter. The diameter of a prop decides how much water you will disturb while the pitch determines how quickly you push the water displaced out of the way. The twist of the blade of the wind turbine or the propeller is related to the operating point. Promotes quiet and vibration free operation. The calculator will spit out the optimal diameter and pitch for your unique situation. You will then be able to filter based on diameter, pitch, material, # of blades, etc. The top speed targeted is 35knots, don't know if it is right target.
I have noticed, however, that as pitch increases, diameter tends to decrease. If you want increased air per revolution, more pitch angle is required. Use the CalcT button to figure the theoretical speed from the actual speed and slip. Aircraft Engine Thrust and Horsepower Calculators Input the required values and click on Calculate. If no black propellers are found, black tape should be placed on the underside of the propeller. Think of a screw and how far it goes in with one full turn. Blade Measurement and Adjustment Instructions For Style “C” Cast Aluminum Blade Propeller Fans (b) Position one blade as suggested in step #3(a) and loosen U-bolts or blade retention clamps until blade can be rotated to correct angle. Adjust pitch to use the same propeller on different engines and airplanes. Beta 43 and PRM150 1:209 propeller size over reving its better to add pitch to a larger propeller and a 17. To prevent the engine from over-accelerating, make sure that you use a prop with sufficient pitch for the size and weight of the boat. Prop Group The prop group that will work with the selected application is represented by a shape with a number within it (some shapes do not have numbers). Starting props should always be a newbie pilot’s first choice. Roof Angles and Rafter Plumb-Cuts. The Gear Ratio between the engine and the prop shaft. The stock propeller is an 11. Propeller Selection. Fixed Pitch Propellers from ZF Marine Manufacturing Location ZF Marine Zhuhai ZF Marine Kaohsiung ZF Marine acquired FPS-(Zhuhai) in 1998 since then Faster Propulsion System Co. 75 inch pitch.
I've read that reducing the pitch by 2" roughly would increase the rpm at wot by 400-450 rpm. Press the calculate button to display the results. If you do not know you requirements, let us help. 4" copper prop Enjoy Free Shipping Worldwide! Limited Time Sale Easy Return. You can enter any four of the 5 variables (engine rpm, gear ratio, prop pitch, prop slip, and boat speed) and it will calculate the 5th one. The Gear Ratio between the engine and the prop shaft. So a prop with a large diameter prop with no pitch would not displace any water until pitch is introduced. That's fast! The motors in the larger units are only a little slower. Propeller Selection. PITCH Pitch is the theoretical distance a propeller will move through the water for each revolution (i. This is a "general" application guideline for determining the appropriate propeller size for your vessel. If you are viewing a prop from the rear of a boat and imagine the prop making a solid circle as it spins the diameter will be the distance across that circle. We model the flow through the propeller as shown in Figure 11. Therefore a 24 X 22 stamped propeller means that the diameter is 24 inches. When a propeller is identified as 13 3/4 x 21, it has a 13 3/4" (35 cm) diameter with 21" (53 cm) of pitch. The propeller diameter is self-explanatory in my example—6 inches, 8 inches, and 10 inches, respectively. The first is a demonstration program which can be used to calculate thrust and torque coefficients and efficiency for a relatively simple propeller design using standard linearised aerofoil section data. A propellers diameter is usually the single biggest determinant of efficiency of a propeller and subsequently the entire power train of an installation. The blade pitch angle is a critical factor in the overall performance of the propeller. Otherwise circular Tip Speed is shown.
Mercury's Prop Selector Mercury's: prop selector is based off a complex formula to calculate the appropriate prop based on an aproximation of your hull's performance charecteristics. 2:1) The Pitch of the propeller, measured in inches. Smaller prop diameters generally go with smaller engines, or with fast high performing boats. 5 pounds, using 4. In fact, the "screw propeller" concept is literally making reference to that the propeller works exactly like a screw. "We had some boats at a lake at 6,000 feet in Mexico," he says. In the real world the engine cannot rotate a stalled prop as fast as a lower-pitch prop would be rotated! By entering higher pitch with leaving other details the same, the calculator can NOT update the entered RPM but it will increase the required power (or vica versa)!. Pitch & Diameter. And this line intersects the flank in such a way such that the width of the threads and the spaces between the threads during their engagement is same, In this case it makes a PERFECT thread. If yours is a Mercury, Mariner, or Mercrusier, write down the Quicksilver prop number it finds for you in the 3 bladed aluminum prop. Those sizes are referred to as diameter and pitch. The problem is that water produces drag against the boat and propeller, so the propeller never actually reaches its full pitch. Vicprop, marine propeller specialists. Marine Propeller Calculators We (RBBI) have created a JavaScript based RBBI Prop Calculator that works on the internet. Every CNC propeller is delivered in a Mercury Racing Propeller Case. For engine models not mentioned here, please e-mail or call (231) 759 8596.
With R/C gas boats, 65 to 80 mm is the standard. Calculator Ruler Narrow Scotch or Electrical Tape. At the same time, a smaller pitched leading edge reduces laminar separation due to a lower pitch angle. Later, we sometimes move the propeller back and forth a bit, but never more than 1/8 of a turn. The 3- and 4-blade propellers offer more or less the same speed as the 3-blade fixed propeller across the full rev range. To be able to select or upgrade to a new propeller, you must understand these terms and how they translate to real-world performance. Most times, pitch can be altered by a good prop repair shop, without the need for purchasing a new prop. The slip will not allow us to attain the pitch speeds of a propeller. For any two props of the same type and diameter, but different pitches, the prop with lower pitch will have lower incident angle of attack than the prop of higher pitch. Understanding RC propeller size. 5 HP 35 degrees, 14,700 CFM, 34 pounds, using 9. Pitch diameter is a term used to take measurements of the diameter of a gear or a screw using pitch points. Select from these Evinrude models to find propeller style charts. A three blade propeller if the activity extension is performed. Fan performance is shown at the maximum RPM allowed for the stated Prop/Fan diameter. The pitch of a propeller is the distance the propeller would move in one rotation, if it were moving through a soft solid.
7 = Pp 6 x 0. An approximate relationship as a function of the number of blades is as follows: DN = 4 1 2 2 ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ Bn D DN is the diameter of a propeller of N blades D2 is the diameter of a two-bladed prop. Yes, its true that the effective diameter is APPROXIMATELY between the major and mean diameters. Increase the size and pitch also add cup to the blades. Propeller size chart frame and prop size on a side note in you should be able to calculate the launch sd if measure distance between cuts and have rpm of minimum frame and prop sizeHow To Choose Motor And Propeller For Quadcopter The Top 10 BestDrone Propeller Size Chart Best Pictureodel OfThe Ner S To Read More ». Select Stainless or Aluminum. Props are only meant to be selected with respect to pitch. Optimize your boat's performance with a propeller from Michigan Wheel, Stiletto, Solas, Quicksilver, or Comprop. Measure from the centre of the propeller hub to the tip of the blades and multiply this by two. Aircraft Engine Thrust and Horsepower Calculators Input the required values and click on Calculate. I Have a lund 1625 fury xl with a 50 hp e-tec that came with a 13x19 pitch ssp prop when I bought the motor new. [ Home ] [ Up ] [ Aqualoy 17 Propeller Shaft ] [ Aqualoy 19 Propeller Shaft ] [ Aqualoy 22 and 22 HS Propeller Shaft ] [ 316 Stainless Steel Propeller Shaft ] [ 17-4 Stainless Steel Propeller Shaft ] [ Nitronic 50 Stainless Steel Propeller Shaft ] [ Propeller Shaft Tolerance Tables ] [ How To Size A Propeller Shaft ] [ Propeller Shaft Bearing. If they are NOT the same, however, the spreadsheet will take that into account and use the smaller. 6 the formula for static thrust is Thrust = P X D^3 X RPM^2 X 10^-10 oz. "Pitch" is a term most commonly used when referring to propellers. in addition, it is important to understand the effects of ventilation, cavitation, materials, and other application variables on propeller performance. For Extra Protection Add:. Shafts are machined all over but of a larger diameter and smooth turned in way of the bearings.
Measure the peak RPM, note the diameter and pitch of the propeller (the marked pitch may not be the actual pitch, see pitch measurement) Select the value for the number of blades and pitch of the propeller using the list box's. RC AIRPLANE PROPELLERS. All props will be described by two numbers, such as 13 x 21. Boat speed, Propellor pitch and diameter - Pontoon Boat Jul 30, 2009 · MrGadget wrote:With 10 people on board (~1500 lbs) plus your gear, 20 mph would be wishful thinking. size and pitch [twist] of the prop control the amount of air moved per rev I think like a boat prop the HP is more important then torque for the prop size as most motors torque peak is at a much lower RPM then HP peak ask a prop maker what they use. If your wanting the most top end speed stick with the three blade and change out to a aftermarket prop from a custom shop. The propeller speed is 200 rpm, the boat speed is 20 knots, and the thrust reduction factor (t) is 0. revised 8-26-24. If the airplane is flying then the propeller's pitch becomes more important, since the air that. When referring to propeller size, such as 3 x 13 x 18, the first number details the diameter of the propeller and the second number is the pitch of the propeller. Such small movements do not cause induction of air into the oil system. Hi, I have a 20' bilge keel carvel cabin boat. Therefore a 5045 prop has a diameter of 5. Most props are left hand props, except for the ones labeled with an "R" after the prop Size. Shopping for a new propeller, whether it's simply to replace a damaged one, or because you're looking for better performance, can be a daunting, confusing process.
IVOPROP In-Flight Adjustable Ultralight Props: The ability to change the pitch in flight is as significant for the airplane pilot as for the driver of a car to shift gears in the transmission. NOTE: Often two or more pitch sizes are listed for a given Boat Length. present = pitch of the propeller which is preventing the engine from reaching its rated rpm. The details of propeller propulsion are very complex because the propeller is like a rotating wing. The pitch is the most significant number in the description. B) Blade rate harmonics Slope -6 dB/Octave Frequency. Although there are variable pitch props available for RC planes, we'll assume for now that we're dealing with standard fixed pitch propellers. However, with this simple concept and multiple pitch measurements you can use it on just about any size propeller from a tender to an ocean liner. Your looking for a replacement and a friend has an old propeller but is not sure of the size. A larger propeller size does not mean that you will be able to fly faster. Basic Pitch Dia. A three blade propeller if the activity extension is performed. Yamaha propellers are designed to harness the power of Yamaha outboards. Evinrude Propeller Selector for Boat Motors Evinrude WOT RPM Range Chart. Pitch & Diameter. Sizing Propellers Those wanting to actually size a propeller for a boat (determine the best diameter and pitch) may find a free downloadable Propeller Calculator program from Castle Marine in the U. Prop Pitch Numbers Disclaimer: This calculator should NOT be used as an exclusive decision maker when deciding on a prop for your boat. diameters of these propellers can be reduced relative to two-bladed versions while maintaining the same pitch and engine power. There is usually little latitude when replacing a prop and it is wise to stay within a 1/2" diameter of the original-size prop, as a rule of thumb. This Circle Calculator will be a very useful one for the middle and high grade school students do the calculations on circle's area, diameter, circumference and sector.
In most cases this is different from the conventional airfoil datum. The pitch is where things become confusing. I have no experience or suggestions to help with this. Pilot controls the pitch through the toggle switch mounted in the cockpit. With a 4 blade Trophy Plus 17 they got top speed of 45. Running through a prop calculator, and ASSUMING a 20% slip at WOT, it works out that it is a 21 pitch prop. Smaller prop diameters generally go with smaller engines, or with fast high performing boats. The diameter and pitch of your propeller will usually be stamped on the side and will read something like "14X9X3 LHS. Ray Brazier is considered an authority on rigging boats with 4 decades. The prop must be well balanced. Ray Brazier is considered an authority on rigging boats with 4 decades. One of the most common questions we're asked is what is the difference between a 3 blade and 4 blade propeller, and which one is right for me. However, pitch must also affect not only thrust but also efficiency. Thus a different propeller diameter has to be selected for the same available power. 6 meters; The geometric pitch does not correspond at actual movement of the propeller, the difference between the geometric pitch of the propeller and the effective pitch of the propeller is the slip of the propeller. Adjust pitch to set engine "break-in" RPM. Example "4" Enter the motor kv provided by the manufacture The Tip and pitch speed of the prop is calculated in km/h.
To help you understand our test, we will take a quick look at propeller theory and numbers. Sensenich Propeller manufactures and services our own Fixed Pitch Wood, Aluminum and Composite Ground Adjustable. Diameter is a function of bite while pitch is a function of how much a prop will advance forward in a given rpm. Define propeller pitch. For instance, a screw with 10 mm of pitch will advance 10 mm for every complete turn when hit by the screwdriver. Find your variable-pitch propeller easily amongst the 41 products from the leading brands (MAN Diesel, Schottel, Wärtsilä, ) on NauticExpo, the boating and maritime industry specialist for your professional purchases. To illustrate the differences in performance and economy among various props, we had the opportunity to try nine different propellers on a 1983 25′ Pursuit cuddy-cabin boat repowered with new 150 hp E-TEC outboards. while overloaded = engine rpm under normal working conditions when. 75 rpm with 24 VDC), just about perfect for a rotator of this size. 28" This propeller does come as a bullet hub, contrary to the image. Pitch is the distance the screw traveled during one complete turn. Most times, pitch can be altered by a good prop repair shop, without the need for purchasing a new prop. We also sell new propellers and distribute for all major manufacturers. Find the right propeller in 3 easy steps! 1. All parts are here and the nut for shaft has been bored out to fit the slight. When we got the boat the prop shaft and prop were already there. The size of a propeller is usually expressed in the form diameter x pitch. 6 meters; The geometric pitch does not correspond at actual movement of the propeller, the difference between the geometric pitch of the propeller and the effective pitch of the propeller is the slip of the propeller.
Boat propellers are a vast and interesting topic, and if you want to understand all the ins and outs, try poking through our comprehensive inventory of articles. As the air whirls around the fuselage it pushes against the left side of the vertical tail (assuming it is located above the propeller's axis), causing the plane to yaw to the left. You must look at the prop's diameter, pitch, cup, rotation, bore, and more. On a model airplane, you should not only try different pitch props, but different diameters as well. There is a lot of terminology and measurements that the everyday boater won't understand. For normal elevation, a 19 inch pitch 3 blade works well with the 2. The FS Propeller is currently in testing phase and we will share the results. For the forty years following the first flight of the Wright brothers, airplanes used internal combustion engines to turn propellers to generate thrust. Bigshot: posted 09-16-2002 04:38 PM ET (US). Optimal Propeller Calculator (Designed for RC Aircraft Models) The Diameter Pitch RPM Perimeter Speed Thrust kg Thrust pound Thrust oz Fly speed km/h. Many factors are taken into consideration when matching a specific branded prop to a boat so when going ahead use specific manufacturers guidelines. An approximate relationship as a function of the number of blades is as follows: DN = 4 1 2 2 ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ Bn D DN is the diameter of a propeller of N blades D2 is the diameter of a two-bladed prop. Find out which propeller size (diameter and pitch) you have now (written on your prop) 2. PITCH Pitch is the theoretical distance a propeller will move through the water for each revolution (i. 3 x 13 pitch, right hand rotation propeller from Mercury Marine, part number 48-8M8026630. It can also be looked at as the distance across the circle that the propeller would make when. PERIOD / VINTAGE SCALE PROPELLERS have the same pitch ratio as standard scale props and the same efficiency, but are used where a specific style is needed, especially WWII pattern with the distinctive pointed boss and rounded blades. These will be used as guides for carving the prop. Wyeast's Pitch Rate and Growth Calculator is a tool for planning a propagation scheme to achieve proper cell counts in the fermenter. In reverse: the Max-Prop provides 80% more power than a comparable fixed blade propeller.
The larger the diameter of a propeller the more horsepower needed to turn it at a given speed. This is the official site of RIB Adventure Team. Re: Prop diameter vs pitch relationship No, Bobbased on the info provided, you are spot on. The calculator will spit out the optimal diameter and pitch for your unique situation. The diameter of the propellers is o. Mercury's Prop Selector Mercury's: prop selector is based off a complex formula to calculate the appropriate prop based on an aproximation of your hull's performance charecteristics. 8, or 10 x 5. Hill Marine is your one-stop shop for props! Find the best deals on stainless steel propellers, boat props, boat racing accessories, prop repair and get prop selection help at Hillmarine. If you are searching for a high. 0), prop pitch (the distance that a propeller would move forward in one revolution), prop slip (the efficiency of the prop, lower at high speed, but perhaps very inefficient at low speed) and the boat speed in mph. Unfollow mercury propellers to stop getting updates on your eBay Feed. 8 and pitch-diameter ratios ranging from 0. The diameter of most props will go up as pitch goes down in most cases. So a 12-by-20 prop has a 12-inch diameter and a 20-inch pitch. Go out by yourself with the least gear possible and the GPS and see what you get. Basic Pitch Dia. Propellers 2 PARAMETERS AND PERFORMANCES The geometry of a propeller is usually defined by a set of simple parameters: propeller size is quantify by tip diameter, ; advance pitch, D p, is the theoretical axial displacement in one turn as if a reference blade-. Genuine Volvo Penta single propellers for Aquamatic.
Lab Finished versions are for lightweight hulls with natural bow lift. Boat prop pitch refers to the distance of the propeller movements with each revolution. in addition, it is important to understand the effects of ventilation, cavitation, materials, and other application variables on propeller performance. Pitch is the angle of the blades expressed in inches of theoretical travel in one revolution of the propeller. The size of a propeller is defined with two sets of numbers, diameter and pitch, with pitch always following the diameter. diameters of these propellers can be reduced relative to two-bladed versions while maintaining the same pitch and engine power. Find boat propeller available for buying now. The recommended prop P/D (Pitch/Diameter) ratio for sport models is 1/2 to 1/1. The chord length, c, is the straight-line width of the propeller at a given distance along the radius. Diameter is the first number listed in a prop description. pitch; Image courtesy Propeller pages. There are equations where given values are entered to give you the mathematical thrust values…such as prop diameter, chord, mean chord, rpm, , etc…remember a prop is just a rotating air foil and in any forward fligh. Engineered using proprietary information, manufactured to our stringent standards for quality and tested for performance, nothing will maximize your outboard's performance quite like a Yamaha propeller. Even owners of full-scale airplanes with fixed pitch props, like a J-3 cub, can choose between at least two different FAA approved propellers - one called a "climb prop" (lower pitch) and another called "cruise prop" (higher pitch). Mercury 48-8m8021520 Prop Zeus Z10 Pitch 3 Blade Right Hand Ss Boat Propeller. per square ft of the prop disc. Roof pitch can be found by finding the rise over a 12 inch run. Pitch points on a gear could be found if a straight line were drawn up from two of the gear's teeth located side by side and the two lines were connected by a curve. To be able to select or upgrade to a new propeller, you must understand these terms and how they translate to real-world performance.
But, for static thrust the blade angle is also very important - probably even more important than for the design point, where a gearbox can match almost any propeller pitch and flight speed quite well. Adding 1 inch of propeller pitch will reduce WOT RPM by 150 to 200 RPM. Prop pitch should stay consistant no mater the diameter. Take Advantage on Discount Boat Propellers Every Day Low Prices on Piranha and Comprop Propellers. Generally a heavy boat will do better with a larger diameter prop and will likely have a greater ratio reduction. The bigger (slower) the vessel the bigger the diameter. When a propeller is identified as 13 3/4 x 21, it has a 13 3/4" (35 cm) diameter with 21" (53 cm) of pitch. The pitch of a propeller is always stated in even numbers, so the result, 16. For the forty years following the first flight of the Wright brothers, airplanes used internal combustion engines to turn propellers to generate thrust. Example "4" Enter the motor kv provided by the manufacture The Tip and pitch speed of the prop is calculated in km/h. Is it important to know your prop's slip? Only if you care about insignificant, little items like thrust. With R/C gas boats, 65 to 80 mm is the standard. Propellers exist in different length and pitch: The length of a propeller is the diameter of a disc the prop makes when it's spinning; Pitch can be defined as the travel distance of one single prop rotation; The larger the prop (either increasing diameter, or pitch or both), the more energy it takes to spin it. If no black propellers are found, black tape should be placed on the underside of the propeller. When it's time to buy a new propeller, diameter and pitch are the watchwords. This propeller has a pitch that will theoretically result in 24in. Input vessel, engine and transmission details and the program will calculate: Maximum achievable speed, estimated fuel consumption, recommended propeller diameter and pitch, a propeller pitch based on a required fixed diameter, plus it will suggest alternative propeller sizes using different gear ratios to. What is propeller pitch? Pitch is the distance that a propeller would move in one revolution if it were moving through a soft solid, like a screw in wood. Piranha propellers are, and are specially molded and calibrated to ensure the best shock absorption possible, which all but eliminates any damage to the lower unit that can be caused by propeller strikes.
- interesting stuff Here's the biq question for all the aerodynamicists: Big prop, big pitch at lower rpm, or smaller prop at faster rpm? Seems to me the key is getting close to. A prop's pitch is similar to an airplane wing as well, with high and low pressure sides. Also for this option the shaft. Props are only meant to be selected with respect to pitch. Small diameter props are widely used for PPG, light PPC and airboats. If you've got the horsepower to spare, the high pitch prop may give you both the acceleration and. Hi, I have a 20' bilge keel carvel cabin boat. In most cases, the diameter and pitch will be stamped on the hub of your prop. These prop sizes may also vary according to customer and/or. The pitch in inches is the distance which the propeller would screw through the air in one revolution if there were no slippage. The reason is, although the 4-blade is one-inch lower in pitch, it runs more efficiently than its 3-blade competitor, allowing it to run closer to its theoretical speed than the 3-blade, thereby, effectively closing the gap presented by the pitch differential. With this option the thrust force can be calculated for a range of speeds, by varying the pitch-diameter ratio, for a fixed number of revolutions (for which the first revolutions value is taken from the range as given in option 2 ( Input of propeller data. These sizes are for fixed props only, not folding propellers. So by adding propeller RPM to the formula used to calculate propeller loading ( Diameter squared x Pitch) used elsewhere on this site to produce the Propeller Loading chart we can calculate a figure for thrust that. Thus, a lower pitch propeller is recommended. ” The first number represents diameter, the second represents pitch and the third indicates the number of blades, which is often omitted. The following screenshot shows these entries in our calculator: You can see we’ve entered 14 for Diameter and 8 for Pitch. If you are searching for a high. The constant 10^-10 will have to be changed dependent on the prop and manufacturer. In reverse: the Max-Prop provides 80% more power than a comparable fixed blade propeller. Prop Diameter And Pitch Calculator.