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Showing posts with the label motors

Shrediquette derbe evo progress

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Some images of the assembly process...: There is not much space inside the frame, but everything fits. The assembly also went quicker than I thought. I just need to replace all the motor shafts of the Graupner Ultra 2806 2300 kV motors (due to a hard crash), and then I am ready to go. The take-off weight is just 447 grams.

Some thoughts on FPV camera tilt compensation

Almost every 'serious' FPV racer is tilting the FPV camera up in order to have a better image during fast flight. Angles between 10 and 35 degrees seem to be common. E.g. I am using 25 degrees. But tilting the camera with respect to the multirotors horizontal plane has a side effect on the controls (maybe you never thought about it, because you are so used to flying with this side effect). Just to make the effect easier to visualize: Imagine you drank a beer too much and now you suddenly think you are Charpu , Mr Steele or Mattystuntz . You mount your FPV camera with 90 degrees tilt (pointing up vertically) because your best friend told you that all the pros do it like this. In this case, your roll and yaw control will be interchanged: When you move your RC sticks to roll left, your copter will roll left, but looking through the FPV camera, it appears as if you are yawing to the left! And if you move your RC sticks to yaw left, your copter will of course yaw left, but the im...

How to measure top speeds of multirotors

How fast can your multirotor fly? The simplest solution for this question would probably be to attach a GPS device (tracker / OSD) to your multirotor and to read out the maximum speed. But hey, this is pretty imprecise...! GPS devices suffer from measurement noise (e.g. through signal degradation), which becomes problematic on rapidly accelerating objects like our multirotors. More advanced GPS chipsets (e.g. u-blox LEAx) have the option to choose between different filtering modes (e.g. pedestrian, car, airborne), that make some assumptions on the maximum accelerations and movements of the sensor and filter the results accordingly. That will most likely improve the accuracy of the measurements, but still noise might remain. Here is an interesting article on GPS speed measurements , which states that the classical methods to calculate velocities in GPS receivers have an accuracy in the order of a few meters per second, due to significant noise. I was recently attaching a p...

Aerodynamics in racing multirotors!

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Why future racing copters really should look different. by Dr. William Thielicke aka Willa aka Shrediquette ABSTRACT In this article I try to demonstrate why FPV racing multirotors need to look different. Some small modifications to the frame would (in theory…!) result in 70 % higher top speed! All that needs to be done is to align the arms parallel to the propeller flow, and to tilt the main body of the copter by about 40 degrees. I am presenting a very simple and robust racing copter design that incorporates these ideas. Furthermore, I am calculating the aerodynamic drag of different copter concepts using basic equations. The aim of this article is to make you realize the importance of aerodynamics and to stimulate people to design more innovative racing frames. INTRODUCTION Until recently, multirotors were mainly used as a “hovering device” and the top speed of these copters did hardly matter. Now, multirotor racing has become popular and all competitors are seeking ...

New brushless motors

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As some of you might know, I am using Scorpion S-2212-26 motors for quite a while now. I am extremely happy with these motors. Short time ago, SCORPION POWER SYSTEM LTD offered to provide three recently developed motors (prototypes of the SII-2212-960KV) for tests with my tricopter . Of course I didn't say no...!! I had the opportunity to test them recently, and these motors are absolutely great! They seem to be even more efficient and powerful than the S-2212-26 I used before. These motors stay absolutely cold (prop: EPP 10x4.5'') even if I do aerobatics with my copter. I am not a real expert with motors, but if no heat is produced, all the available energy should be converted to mechanical energy/ thrust... And that is also what it feels like :-D . So, I would absolutely recommend to use these motors with my tricopter! And last but not least, they look pretty nice...