Hello,

I'm taking personal time off this week, dedicating most of my time to getting my DARPA Lift Challenge Small Unmanned Aviation System (sUAS) documented for the May 1 documentation deliverable to DARPA regarding the design. I think I have a viable contender now, after four months of try and die ideas and concepts (aren't deadlines wonderful?), but the amount of build effort, vendor and supplier lead times, and tooling, as well as future crash-related depletion of my spares inventory, may wind up knocking me out of the flyoff in August. Can't do more than try. It hasn't been cheap and it has eaten all of my spare time the past five months. 

If my drone design does get invited by DARPA and makes it to the flyoff, Lee Goldberg and I plan to cover the event and I'll be covering the details of the design in subsequent blogs - it is a very interesting, multi-disciplinary, design project, which is why I'm doing it. I already have a provisional patent written up that I need to send to my patent attorney today or tomorrow and am working another invention that's arising from this (the devil is in the details, a mere idea is worthless). The IP development and patent filings is my main reason for playing in this new sandbox. I'm still shopping around for a decent battery, but think I can get by with what I have chosen.

Right now, it's looking like I'm north of 5:1 on payload to empty bird weight ratio (that can change), DARPA cuts the prize money in half if nobody gets past 4:1—the mere fact they said this becomes obvious—the Sikorsky Skycrane or Boeing CH-47 Chinook heavy lift choppers, and the best drone I can find that money can buy (the DJI Freefly Alta X), are about 1.05. The challenge is not just about the lift but the endurance to do a heavy lift as VTOL to 250 feet AGL, run for 4 nautical miles on an insanely narrow 100 foot by 1000 foot long course, do a VTOL landing, unload, then VTOL to 250 feet and run for another nautical mile to a VTOL landing. The P/W ratio is the primary determinant for who wins.

I expect a lot of inflight RUDs (Rapid Unscheduled Disassembly) as we all push the structural limits of our lightweight designs - I primed the DARPA organizers with concerns over this reality and over the ensuing lithium battery fires from crashes and excessive sustained current draws. Fail Big, Fail Often, Go Home...with your project in an urn. This is all to be conducted over a few days during a giant RC aircraft festival by Flite Test, so practice your duck and cover if you're attending in early August.

We also have an In-Service Day for us (adjunct) professors at the college this week, plus I'm going in for my Part 107 Commercial Drone Pilot Exam tomorrow (flying my drone design is considered commercial because of the prize money we all have a fat chance of winning against Big Aerospace, but I can't get invited without my pilot license from the FAA - I've been studying as well this past week, lol). I'm also prepping a couple of my accepted bronze sculpture entries for submission this week to display in the college art gallery. Despite my PTO and the Friday DARPA deadline, I still have a lot of meetings, driving and studying I can't get out of and I committed to getting this newsletter out twice this week. Who needs sleep?

Back at the ranch, Electronic Design's motor control design series continues with Part 3. There are more article parts imminent - I think James said there are eight parts.

Check out the other articles and news below, including the interesting links I've come across to date - I've read all those this past week as well.

Back to designing my wing spars,

enjoy the content,

-andyT

p.s. I also have my new weekly cartoon series to create/post for Electronic Design Weekly. Last week's is here. This week's is Automotive-related, so hang a printout up on your cube wall or in a meeting room if it gets a chuckle.