Shrediquette - the award-winning multirotors by William Thielicke

Idea Ever wondered what propeller or what motor performs best for your needs? Here is a simple way to determine the performance of different propellers (or motors) directly in flight, using your multirotor, the blackbox and some math. In the past, a lot of static thrust tests have been done to determine the current, thrust and efficiency of multirotor propulsion systems. However, they don't tell you anything about the propeller or motor performance in fast forward flight. Aerodynamics in forward flight and with a non-uniform inflow of the air are very different from static measurements. My questions were: What propeller has the better acceleration? (acceleration performance of propellers is theoretically closely linked to the 'grip' during turns. Because turning is also just an acceleration, see this post )   What propeller will reach the higher top speed?  And which one decelerates better when throttle is cut? Method My idea was to mount one kind of prope...

I am currently checking the feasibility of computational fluid dynamics with racing drones in Autodesk CFD2018. This is one of my first attempts to simulate a simple copter draft by Heiko Schenk. I am still very new to CFD, so I am looking for feedback too. I am including the effect of the propeller jet (velocity distribution and swirl) and also the motor housing rotation. The flow velocities of the propellers were calculated in JavaProp (33000 RPM, 360 Watts, 30 m/s, 3 blades, 5 inch diameter). Watch this video for more information and some results:

This design was just finished, I am still searching for the perfect propellers. The performance is very good already, but the props are not durable enough. The MTM is 150mm, I noticed that quads fly cleaner and with less noise when there is some extra space between the propellers. Here is my setup Recoil stretch frame, 2.5mm carbon Weight without Lipo: 80g Take-off weight: 135g AMAX inno 1105 4000 kV Emax Bullet 12A ESCs Tattu 4S 450 mAh 75C Runcam Swift micro NTSC, 2.1mm FXT FX806T VTX, 25 mW Frsky R-XSR Emax femto (still my favorite FC although I haven't tried many) XT 30 AMAX inno 3030 3-blade props

Summary: FPV racing multirotors with side force generators (SFGs), will drift less during turns, making them potentially faster on race tracks  (watch the video comparison here ) . But the SFGs need the be carefully placed and dimensioned, so that aerodynamic centre and centre of mass are at the same position. Otherwise it will not work.  Introduction Recently, I was thinking about how to improve the handling of racing copters. I noticed since quite a long time, that different copters behave quite differently in fast turns: Some drift quite a lot (especially when they carry a larger battery or an action cam), others drift less. I was always preferring copters that drift as little as  possible. That is also why I am trying to reduce the weight of my copters as much as feasible. The amount of drift depends on the weight of the copter and the lift and drag of the fuselage for sideways air streams (side-slip). The larger the lift and drag, the more side force the fusel...

I think I now have all the parts that I need to start assembly. The frame weight is 77 grams (without electronics). Here is the latest teaser: https://youtu.be/no3FbcdH4LE

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...