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...

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.

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...

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...

This year, the 'International Micro Air Vehicle Conference and Flight Competition' ( IMAV2014 ) took place on the 13th of August in the Netherlands. I am very happy to announce that together with my team (called 'Dipole', consisting of Prof. Klaus-Peter Neitzke, Dr. Hans-Peter Thamm and me = William Thielicke), we won the second prize in the IMAV competition! Fifteen international teams accepted the challenge and tried to score points in the simulation of a major natural disaster inside a small artificial village. Several tasks had to be solved during a 30 minute time slot: Creating a stitched orthophoto of the whole village; flying through the village and identifying house numbers and survivors inside the houses; observing a given spot; entering a two-storeyed house and flying through the rooms while identifying objects in the rooms (see the detailed rules here ). Points were awarded for each of these tasks, and summed for the final score. Our team used three d...

We had a small multirotor-meeting here in Bremen last weekend, and there were also some people that were up for a FPV-competition. So the GEMiNi had its first opportunity to do what is was built for: Race! A track was quickly built from chairs, tape and some other stuff we found. It was a lot of fun (well I could do FPV-competitions every day because I like it very much to fly "for a reason"), and the GEMiNi finished first. See the video here: https://vimeo.com/75664628