KiCad Features

KiKit is a panelization utility that supports panel fiducials (alignment markers.) (EasyEDA and Altium have a built-in panelization UI.) The KiCad fiducials key is “F”.

Panelizing boards within KiCad – Random KiCad Tips

– there is a component table for bulk mgmt. of parts

– use “X” icon for marking pins as No Connect, otherwise DRC will emit errors

– there is a high-frequency creepage plugin that is 2D (Altium has a built-in 3D creepage checker)

KiCAD Quick-Start Tutorial

High Power Circuit Board Design (PCB) – KiCad 5 – : Part 1/2,
Part 2/2

Posted in kicad, Linux, Open Source, Tech | Leave a comment

Github Actions Demo Repo with Several Programming Languages

I created a Github repo to test using the Github Actions build workflow feature to lint several programming languages (Perl, Python, Ruby and Bash) in different directories simultaneously.

Github Actions is pleasant to configure and seems very useful.

The Perl-specific workflow (only 33 lines) is here.

[Screenshot: GitHub Actions UI showing 4 workflow run results]

Note that Github Actions can be used to spin up a Jenkins VM, then you can run existing Jenkins scripts, like Pipeline, etc.

Posted in Cloud, Perl, Tech | Leave a comment

OpenLayers 5.3.0 and “SyntaxError: missing : in conditional expression”

Just a PSA for Openstreetmap Openlayers 5.3.0 API users.

The rawgit CDN ol.js file appears to contain a malformed ternary operation that causes browsers to not create the ol object, breaking map programs.

The Firefox web console says:

SyntaxError: missing : in conditional expression ol.js:1:34694

The solution is to switch CDN from rawgit to like this:

So definitely test your existing Openlayers code on a current version of Firefox.

There’s only a couple of searchable references starting May, 2020, so it’s something fairly new.

Posted in Open Source | Leave a comment

Very Light Jet (VLJ) Market History to 2020

Like everybody connected to the aviation industry, I watched the Very Light Jet (VLJ) market hype (mostly around Paul Allen’s Eclipse 500,) in 2002 and wondered how the market would shake out. After the Eclipse announcement, around 10 competitors announced they would build a VLJ, too.

VLJ’s are characterized by being lower-cost than other private jets, and being certified for single-pilot (SP) operation. However, “lower-cost” increased from $837,000 in 2002 to $3-$5 million in 2020. The key technology in 2002 was a Wiliams cruise missile engine, but that turned out to be under-powered for the Eclipse back then and the engines were upgraded to P&W. A Williams jet is used in the Cirrus Jet today.)

The Eclipse (twin P&W, 370k, ~$1M, 267 made) company was predicted to fail because of the ultralow pricing and company mfg. inexperience. And it did in 2008, although it shipped a few hundred airframes in various stages of completion. Most of the wealthy individual buyers moved on to the Cessna Mustang (twin P&WC, 340 knots, $3.3M, 469 made), which was much more expensive but had the backing of Cessna/Textron.

What’s interesting is that Eclipse reported a major deal with an air taxi, Day Jet. I was skeptical of the deal at the time, but they did receive about 20 jets and provided service until also failing in 2008, although I wonder about the dispatch rate for a v1 jet.

Besides the Cessna Mustang, another successful jet that eventually emerged was the Cirrus Vision SF50.

The Cirrus Vision SF50 (single Williams, 300 knots, $2.7M, 170 made so far) was certified in 2016 and the shipment volume winner for 2018 and 2019. It and the Embraer Phenom 100 (twin P&WC, 400 knots, $5 million) are the only VLJs currently being made, with the HondaJet available at twice the price ($5.5 million.)

(Note that Cirrus (and most small US airplane companies) are owned by Chinese companies as of 2020.)

On Apr. 18, 2019, an FAA AD was issued after 3 incidents involving AOA sensors were reported. Aerosonic, the AOA supplier, shipped bad units to Cirrus, and the SF50 fleet was grounded until replaced. The effect was the same as the 737 MAX accidents, although Cirrus had a hardware, not a mostly software, problem. It’s interesting that a ferry flight was allowed to repair it.

W: Eclipse 500, Cirrus Vision SF50, Cessna Citation Mustang (Model 510), Honda HA-420 HondaJet, Embraer Phenom 100

Textron Ceases Production of Cessna Citation Mustang

Posted in Tech | Leave a comment

Software Fix Found For A220 Engine Acoustic Resonance Shutdowns

Very interesting:

“Airbus has determined that acoustic resonance is behind the destruction of four engines on its new A220 airliners in the last couple of years. The company has come up with a software fix for the condition, which caused in-flight shutdowns of the Pratt & Whitney geared turbofan engines on three Swiss flights and one on an Air Baltic aircraft.”

Engine makers commonly use remote telemetry, so I’m a little surprised it took a couple of years to pinpoint that. But I’m sure they’ll be adding acoustic sensors now.

Acoustics are a surprisingly big deal in aerospace. HondaJet’s composite fuselage rang like a bell and even passengers needed headsets, so the new Elite version focused on reducing cabin noise by 3 db (half.) Software Fix Found For A220 Engine Shutdowns

Posted in Tech | Leave a comment