Shrediquette - the award-winning multirotors by William Thielicke

Here are some renderings of my latest frame concept. It has a very small frontal area and should reach high speeds. The diagonal motor distance is 210 mm and I will use 5.5 inch propellers ( Graupner Race-Prop or C-prop).

This is a follow up to the previous post on tilt compensation . I made a video where I explain what FPV camera tilt compensation is needed for, how it works and how it looks like in flight: https://youtu.be/gXeaINFpvow In FPV camera tilt compensation, control inputs (RC transmitter --> FC) are transformed to the local frame of reference of the camera . The control outputs (FC --> motors) may additionally be transformed to the local frame of reference of the propellers (if e.g. the props are tilted or the FC is mounted at an angle - use parameters like 'board align' for control output transforms).

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...

Introduction In part 1 of this article on multirotor aerodynamics , some ideas on how to reduce the aerodynamic drag of racing multirotors was presented. I was also designing a tilted-body racing quadrotor called " Shrediquette DERBE ". There were not yet any flow measurements of multirotors flying at high speeds. Therefore, I had to make quite a number of assumptions on the aerodynamics of a racing copter. This time, I am presenting some flow measurements, along with some potential optimizations for the next version of the "Shrediquette DERBE" Methods Recently, I had the opportunity to do some flow visualizations in a large wind tunnel at the Bremen university of Applied Sciences / Dept. of biomimetics (which is the place where I worked one year ago). I brought the Shrediquette DERBE  and mounted it inside the wind tunnel. Prior to the measurements, I did some tests to determine a realistic flight speed and the appropriate pitch angle. The...

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...

Here are some images of my racing copter. Some soldering of the ESCs etc. still has to be done. I am also waiting for some resistors and capacitors for my flight controller to arrive... But I guess the maiden flight will be this weekend :-D.

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 ...