tag:blogger.com,1999:blog-5854741938955568545.post8999297718123633974..comments2021-11-25T21:01:35.890-08:00Comments on ElectricRCAircraftGuy.com--RC, Arduino, Programming, & Electronics: Propeller Static & Dynamic Thrust Calculation - Part 2 of 2 - How Did I Come Up With This Equation?Gabriel Stapleshttp://www.blogger.com/profile/10071071884455787806noreply@blogger.comBlogger55125tag:blogger.com,1999:blog-5854741938955568545.post-51538338824845229942021-09-29T10:53:27.849-07:002021-09-29T10:53:27.849-07:00Yes, so long as the propellers are in a side-by-si...Yes, so long as the propellers are in a side-by-side configuration, NOT a stacked configuration. Ex: X-4 configuration is fine; just sum the 4 motor thrusts. X-8 configuration will have additional error though, because each arm has 2 motors with the propellers stacked on top of each other, causing thrust interference and meaning my equation is not as accurate for that situation. See also <a href="https://www.electricrcaircraftguy.com/2014/04/propeller-static-dynamic-thrust-equation-background.html?showComment=1632937760930#c257941729645350640" rel="nofollow">my comment here from September 29, 2021 at 10:49 AM</a>.Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-87808769008472540562021-09-29T10:51:27.514-07:002021-09-29T10:51:27.514-07:00Yes.Yes.Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-80234623921911044232021-09-29T10:50:50.950-07:002021-09-29T10:50:50.950-07:00See my comment here from September 29, 2021 at 10:...See <a href="https://www.electricrcaircraftguy.com/2014/04/propeller-static-dynamic-thrust-equation-background.html?showComment=1632937760930#c257941729645350640" rel="nofollow">my comment here from September 29, 2021 at 10:49 AM</a>.Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-5736628221824841232021-09-29T10:50:42.955-07:002021-09-29T10:50:42.955-07:00See my comment here from September 29, 2021 at 10:...See <a href="https://www.electricrcaircraftguy.com/2014/04/propeller-static-dynamic-thrust-equation-background.html?showComment=1632937760930#c257941729645350640" rel="nofollow">my comment here from September 29, 2021 at 10:49 AM</a>.Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-2579417296453506402021-09-29T10:49:20.930-07:002021-09-29T10:49:20.930-07:00Go to the first article, click the spreadsheet lin...Go to <a href="https://www.electricrcaircraftguy.com/2013/09/propeller-static-dynamic-thrust-equation.html" rel="nofollow">the first article</a>, click the spreadsheet link, follow the directions at the top of the spreadsheet, insert your values and view the output thrust at the desired airspeed. Multiply the value by the number of motors you have producing this thrust.Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-42363757439428950432021-09-29T03:29:53.189-07:002021-09-29T03:29:53.189-07:00TWIN / DUAL PROPELLER AND MOTOR
DIAMETER = 24 INC...TWIN / DUAL PROPELLER AND MOTOR <br />DIAMETER = 24 INCHES <br />PITCH = 9 INCHES <br />RPM = 3741 <br />Please help me dynamic thrust calculation for this configuration of twin / dual motor Anonymoushttps://www.blogger.com/profile/05027021746368583779noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-7432692340936509452021-09-29T03:26:05.587-07:002021-09-29T03:26:05.587-07:00I want to calculate dynamic thrust for two motors ...I want to calculate dynamic thrust for two motors with two propeller both propeller having same diameter and pitch and rpm <br />diameter = 24 inches <br />pitch = 8 inches <br />rpm = 3741 <br />please help me with how to calculate dynamic thrust with this data ( assume other variables ) <br />Anonymoushttps://www.blogger.com/profile/05027021746368583779noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-69713591634141093432021-09-28T22:32:36.799-07:002021-09-28T22:32:36.799-07:00How to calculate Dynamic thrust of dual motor havi...How to calculate Dynamic thrust of dual motor having two propellers?<br />Jayeshhttps://www.blogger.com/profile/13745189151030795916noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-31494099588996645122021-09-28T09:34:59.536-07:002021-09-28T09:34:59.536-07:00Just use the standard 1x motor / 1x 2-bladed prope...Just use the standard 1x motor / 1x 2-bladed propeller equation above, and sum the thrusts. This assumes the motors are both pulling or pushing in the same direction. If you have 1 motor producing 2.2 lb of thrust and another producing 2.3 lb of thrust, add the two together to have a total thrust of 2.2 lb + 2.3 lb = 4.5 lb, again, assuming their thrust is being produced in the same direction.Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-9212436316909759032021-09-28T06:31:47.196-07:002021-09-28T06:31:47.196-07:00What is the formula for dynamic thrust calculation...What is the formula for dynamic thrust calculation for dual / twin motor ( two motor with two propeller )Anonymoushttps://www.blogger.com/profile/05027021746368583779noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-63461277200779846152021-01-19T15:10:48.197-08:002021-01-19T15:10:48.197-08:00Are these equations specifically for 2 bladed prop...Are these equations specifically for 2 bladed propellers? Anonymoushttps://www.blogger.com/profile/15248797801615290467noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-73761662669413993162020-12-24T11:56:30.686-08:002020-12-24T11:56:30.686-08:00Please see these comments about 3-bladed props, mu...Please see these comments about 3-bladed props, multi-bladed props, number of blades, etc.: <a href="https://www.electricrcaircraftguy.com/2014/04/propeller-static-dynamic-thrust-equation-background.html?showComment=1401497360928#c4348409272506596959" rel="nofollow">comment 1</a>, <a href="https://www.electricrcaircraftguy.com/2013/09/propeller-static-dynamic-thrust-equation.html?showComment=1380029669095#c839465916124560787" rel="nofollow">comment 2</a>, <a href="https://www.electricrcaircraftguy.com/2013/09/propeller-static-dynamic-thrust-equation.html?showComment=1508737294388#c2046412342224088407" rel="nofollow">comment 3</a>.Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-28185788034586758322020-12-24T02:37:11.980-08:002020-12-24T02:37:11.980-08:00hi, im designing an airboat. i look the catalog of...hi, im designing an airboat. i look the catalog of airboat propeller. There variety type which is the size of the blade and the number of blade. can you explain me more how can i relate this equation with size of blade and number of blade in 1 hub ?<br />Anonymoushttps://www.blogger.com/profile/07155777636162085216noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-78263458779121089112020-10-19T22:21:51.732-07:002020-10-19T22:21:51.732-07:00Awesome job man! I've been looking for this k...Awesome job man! I've been looking for this kind of equation for a long time (and the explanation and logic to go along with it). I'll be applying it to quadcopters for now, and try to make my own extensions. Thanks for sharing your findings and research!Anonymoushttps://www.blogger.com/profile/00789711066086491404noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-64454078279191433302020-09-08T20:31:27.883-07:002020-09-08T20:31:27.883-07:00Yes that was really very clever approach😇👍Yes that was really very clever approach😇👍Devhttps://www.blogger.com/profile/01298787152511407159noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-28821203828542794232020-09-08T20:26:05.030-07:002020-09-08T20:26:05.030-07:00Absolutely genius bro....I literally found that ju...Absolutely genius bro....I literally found that just knowing simple equation may take some efforts but it's worth it....thanks for motivating me😇Devhttps://www.blogger.com/profile/01298787152511407159noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-74756190000938170492020-08-27T07:37:38.971-07:002020-08-27T07:37:38.971-07:00WOW! I sat down to start finding prop test data i...WOW! I sat down to start finding prop test data in order to basically do exactly what you've just awesomely shared with us all - YAY!!!<br /><br />I've written a tool to create ideal propellers (I called it "Airfoil Tools" - it's a free plugin for Fusion360). Right now, it's creating turbines beautifully, because we know betz law, so I was able to work the math. The problem with creating a perfect driven propeller, is that in order to know the correct pitch angles*, I need to know the flow rates, which are determined by the pitch angles... catch-22... or it was, before you came along :-)<br /><br />In reality, we actually also need to know the speed and chord at each station along the blade, so we can select the ideal airfoil shape to suit that, and these ideal shapes actually perform best at their own specific angle-of-attack, which needs to be added on as well - plus the entire result then needs to be "bent" in a circle around the axis (these airfoil sections go in circles - not straight lines).<br /><br />Similar to you, I used excel fitting on my (8 years worth) of particle-swarm optimiser results to try and give the optimiser a head-start when finding ideal shapes (and to avoid them being too raggedy) - I posted my research in comment 16 here: https://forums.autodesk.com/t5/fusion-360-api-and-scripts/add-in-announcement-hydrofoil-and-airfoil-tools-seeking-your/m-p/9638061#M10707Chris Drakehttps://www.blogger.com/profile/11378548000217150780noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-61747670437305989652020-08-12T01:47:59.406-07:002020-08-12T01:47:59.406-07:00No I think it will be lower than that. It'll o...No I think it will be lower than that. It'll occur when thrust is equal to drag. For quadcopters it will be dictated by a combination of angle of attack and the vertical component of thrust/weight. Metal Suckers of Dreamlandhttps://www.blogger.com/profile/00570504756608093158noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-73540953594772579342020-08-02T06:54:25.665-07:002020-08-02T06:54:25.665-07:00when i get 0 thrust at a speed, does this means th...when i get 0 thrust at a speed, does this means this is my maximum attainable speed of aircraft.Anonymoushttps://www.blogger.com/profile/06437238298903595291noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-41825058263656661452018-11-13T02:35:23.492-08:002018-11-13T02:35:23.492-08:00This equation is applicable for multi rotors?This equation is applicable for multi rotors?Anonymoushttps://www.blogger.com/profile/17361655634197128597noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-73760734987716128142018-09-24T18:26:23.318-07:002018-09-24T18:26:23.318-07:00Hi Gabriel,
Thanks so much for your work on produ...Hi Gabriel,<br /><br />Thanks so much for your work on producing this equation! It is a great piece of work, and it's very valuable for a class that I'm teaching. In your explanation, you found that your equation had the best fit to empirical data when the final term (d/3.296*pitch) was raised to a power of k2=1.5 (or 3/2), which you found to be an enigmatic result. I think I discovered why the value of 1.5 was the best value for k2. <br /><br />To understand this, let's break down your equation. The first term of your equation is expressed as: RPM * d^3.5 / pitch ^0.5. When you analyze the units associated with each variable, you get: Rev/min * in^3.5 / (in)^0.5. This can reduce to in^3/min, which is essentially a measure of the volume of air that is moving through the propellers per unit of time. When you multiply this value by the density of air (kg/m^3; after converting inches into meters), you can determine the total mass (in kg) moving through the propellers per unit of time. <br /><br />When you analyze the units from the second term of your equation, you get m/s (i.e., a velocity). <br /><br />When you multiply these two units together (after converting minutes into seconds), you get the following unit: kg*m/s^2, which you will recognize as an extremely important unit in physics (i.e., Newtons). Therefore, the only value of k2 that would yield a valid unit for Thrust (i.e, Newtons) is 1.5. Any other number would have yielded an invalid unit for this force. <br /><br />Please let me know if you agree and whether I'm missing something.<br /><br />Thanks again for your work!<br />JohnAnonymoushttps://www.blogger.com/profile/05588172475842112412noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-39539547002642097642018-09-23T00:14:42.119-07:002018-09-23T00:14:42.119-07:00No reference book. It's my equation, hence the...No reference book. It's my equation, hence the title of this article: "How Did I Come Up With This Equation?" That title is intentional.Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-23996528730780306042018-09-22T22:49:29.777-07:002018-09-22T22:49:29.777-07:00what is the reference book of this equation?what is the reference book of this equation?Anonymoushttps://www.blogger.com/profile/12882248972151492048noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-31391595748511846542018-08-21T10:06:01.711-07:002018-08-21T10:06:01.711-07:00Could you explain in more depth why increasing the...Could you explain in more depth why increasing the propeller diameter, increases the reynolds number and efficiency?Anonymoushttps://www.blogger.com/profile/14502841349070726504noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-23102473986182099132018-02-24T14:33:27.503-08:002018-02-24T14:33:27.503-08:00Sort of: I have not accounted for the inefficienci...Sort of: I have not accounted for the inefficiencies related to stacked propeller configurations, but perhaps if you considered a hovering X8 octocopter to have its top propellers in a static thrust condition (no forced inflow velocity) and the bottom propellers to be in a dynamic thrust condition (with inflow velocity induced by the top propellers) you could make the equations work for this case.<br />Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.com