Yaw wag usually occurs on flying wings that use a pair of small winglets instead of a large vertical stabilizer on the centerline. Split rudders, also known as differential spoilers, can be used for active yaw control by increasing drag on either wing independently. However, this requires very rapid corrections that are very difficult to do manually, so this is where ArduPilot comes in. [Think Flight] used its yaw dampening feature in combination with differential spoilers to completely eliminate vertical stabilizers and yaw wag. This is the same technique used on the B-2 stealth bomber to avoid radar reflecting vertical stabilizers. [Think Flight] also used these clamshells spoilers as elevons.
Using XFLR5 airfoil analysis software, [Think Flight] designed built a pair of flying wings to use these features. The first was successful in eliminating yaw wag, but exhibited some instability on the roll axis. After taking a closer look at the design with XFLR5, he found air it predicted that airflow would separate from the bottom surface of the wing at low angles of attack. After fixing this issue, he built a V2 to closely match the looks of the B2 bomber. Both aircraft were cut from EPP foam with an interesting-looking CNC hot wire cutter and laminated with Kevlar for strength. Continue reading “Eliminate Vertical Stabiliser With ArduPlane”→
When people like Bell and Marconi invented telephones and radios, you have to wonder who they talked to for testing. After all, they had the first device. [Jeff] had a similar problem. He got a 10 gigabit network card working with the Raspberry Pi Compute Module. But he didn’t have any other fast devices to talk to. Simple, right? Just get a router and another network card. [Jeff] thought so too, but as you can see in the video below, it wasn’t quite that easy.
Granted, some — but not all — of the hold-ups were self-inflicted. For example, doing some metalwork to get some gear put in a 19-inch rack. However, some of the problems were unavoidable, such as the router that has 10 Gbps ports, but not enough throughput to actually move traffic at that speed. Recabling was also a big task.
The Mandelbrot set, according to Wikipedia, is “the set of complex numbers for which the function does not diverge.” Even if you don’t understand the mathematics behind it, you’ve likely seen the complicated fractal images generated by zooming in on the border of the Mandelbrot set. [Scott Williamson] not only got this set rendering on an Atari, but managed to create animated videos of the results.
Doing the work was no mean feat. While it takes just 10 lines of Atari BASIC to render the set on an Atari 800, getting the animations made and into a modern video format took much effort. [Scott] used the Atari800Win-PLus emulator to zoom in on a variety of locations on the fractal curve and recorded the results over a weekend.
The result is reminiscent of an old-school demo, even if everything here was assembled slowly on modern computers from the raw Atari output. We’ve seen other great Mandelbrot feats before, too, like this real-time explorer built on an FPGA. Video after the break.