So I've just walked back from testing my new custom quad. This was the second quad that I'd built; I'm relatively new to multirotors, but have spent a number of years with fixed wing systems.

Anyway, the specs of this new quad:

Carbon fiber folding frame (this one; other frames share the same name).
2x 5000mAh Multistar 4S 10C LiPos
4x Multistar 4225 motors (610kV, max 330W)
4x Carbon 13" x 5.5" props
4x HK Red Brick 30A ESCs
Pixhawk with typical accessories

Here's a picture of it being built:

Note that the ESCs for all 4 motors are coexisting in the frame, under where the Pixhawk is sitting.

As I do with any multirotor, I tied it down to a heavy grate and then performed a low power motor & control test, keeping power at <20% power and just gently moving the controls around (this is all with the PID settings modified to have zero integral gain).

Unfortunately after about 15 seconds of running it at ~20% throttle and some gentle pitch / roll, it decided it'd had enough and with an eruption of smoke, a juttering of props and a very brief fire, the test came to a halt. I immediately cut power to the system and then physically removed the batteries (which requires the cutting of 4 zipties) from the quad to prevent them from getting any hotter.

Here's a picture of it after it's maiden ground test run:

As you might be able to see, the red ESCs in the center there have burnt up.

Here's a closer look:

Now, I know that Hobby King equipment gets a bad rap by some people, and at first I had thought that perhaps the ESCs had underperformed, as even at max throttle they were only expected to run at about half their max sustained current rating. It was only when I got back to a computer and went to double check their specs / what eCalc theorised the current draw was when I realised that I'd screwed up. If you look up the store page for those red brick ESCs, you'll notice something that I didn't at the time; they're only rated for 2-3S batteries; and I was using 4S...

A small mistake, but with relatively big results.

Well, I haven't had the time to check my other components but from what I've seen so far:

 - Motors and props are fine. Some cables are singed but still appear sealed and intact.

 - Batteries need to be tested; one looks fine, the other has some slight discolouration which may be from the smoke, or it may be from heat damage. I'll probably run them both through a charge and discharge (hooked up to an appropriate ESC and motor) cycle to see if they heat up or swell at all. 

- Pixhawk status is unknown, but it was flashing lights normally as far as I can tell during the accident, so I think it's alright. Its 3DR power supply is a bit burnt, but I don't know if that was due to its proximity to the ESCs or not; either way I'll replace it.

 - Frame looks alright, but either I have some molten plastic on it or the resin partly melted from the heat. I think I should be fine to use it again.

With the ESCs, I'll obviously have to replace all 4, this time, with ones that are 4S compatible. As those ESCs only just fit in there, and because their proximity certainly didn't help keep them cool, I'll be mounting the next set of ESCs probably under the frame.

So there you have it; always double and triple check your components, because the smallest difference of a number can mean the biggest variation from safe flight.

This is just a copy-paste of a new Forbes article:

http://www.forbes.com/sites/gregorymcneal/2014/07/10/drone-users-largely-silent-regarding-faa-rules-that-may-limit-flights/

Users of consumer drones and model aircraft aren’t afraid to share their ideas and imagery in social media.  Surprisingly though, these users have been largely silent when it comes to protecting their hobby from pending Federal Aviation Administration rules — rules that threaten to curtail many uses of the exciting new devices.

Drone users are oftentimes quick to comment when a government official with the FAA or the National Park Service tells them they can’t use their cool toy somewhere.  Realtors, photographers and other potential commercial users have expressed dismay over the FAA’s backwards regulations which allow flying for fun, but not flying for work.

Drone users are also good at organizing to share everything from photos to techniques.  The DIY Drones user group has more than 55,000 members.  The Quadcopters Facebook group has over 2,400 members, and the UAV Legal News and Discussion group on Facebook has more than 1,000 members.  DJI, the maker of the popular DJI Phantom quadcopter has over 72,000 Twitter followers and 3D Robotics has more than 13,000.  Those two companies combined sell tens of thousands of consumer drones each month, who knows how many more Parrot, the maker of the AR.Drone and dozens of other manufacturers sell.  Some blog posts on drones receive hundreds of comments, and thousands of social media shares.  Drone users are certainly active in some places on the web, but they have dedicated very little of their attention towards influencing public policy.

As a supporter of the nascent industry and the decades old hobby, I’m baffled by the lack of pushback against the FAA by otherwise very vocal people.  With just 15 days left before the FAA’s comment period on model aircraft rules closes, tens of thousands of drone users have been largely silent.  For those unfamiliar with FAA regulations, a little background is necessary.  On June 23, 2014 the FAA released their Interpretation of the Special Rule For Model Aircraft.  That interpretation is open for public comment until July 25, 2014.  Once the comment period closes, the FAA will consider public input (and the degree of public interest) and finalize their interpretation.  The game is largely over at that point, as there will be very few opportunities (short of lawsuits) for the drone community to push back against the FAA’s rule.  The stakes are high, yet to date a mere 2,811 comments have been received on the proposed regulation.

FAA regulations of the consumer drone industry, while controversial in social media, have drawn relatively few public comments.

That’s a paltry number.  Brendan Schulman, a lawyer specializing in drones says ”The FAA’s Notice is dense and hard to navigate, and that might be discouraging comments.  The main reason hobbyists should be very concerned is on the last page, where the FAA says that despite Congress’s intent to exclude model aircraft from future regulation, the FAA feels that any part of its existing regulations ‘may apply to model aircraft operations, depending on the particular circumstances.’  That means the agency is poised to arbitrarily tell hobbyists what conduct may be subject to fines — but only after the fact.”

That’s a significant threat to the emergent industry.  While not everyone know’s how to comment on a regulation, other regulations that impact less tech savvy audiences have garnered far more comments.  For example, a regulation having to do with snakes has over 50,000 comments and a petition to amend the standard identity of milk received over 40,000 comments.  It’s simple to submit a comment at Regulations.gov, so perhaps the drone users are waiting until the deadline to file their comments.  But given the number of users, and their passion for the hobby, it’s shocking that the number of comments received thus far is so low.

The lack of response is not due to a lack of media attention or advocacy group organizing.  The FAA’s new policy guidelines were widely covered in traditional and non-traditional media (I have stories on it here).  Moreover, the Academy of Model Aeronautics (AMA), the 1650,000 member group representing model aircraft users posted a call for action to their blog and sent emails to their members.  They even provided their members with instructions on how to respond to the regulation and posted a detailed guide explaining the organization’s concerns.

The AMA has valid reasons to be concerned, “Since 1981, the FAA has said it is fine to fly a model aircraft if you are more than three miles from an airport, and just to notify the airport operator if you are closer.” Schulman explains, “Now, the FAA is demanding that hobbyists request permission in advance from air traffic control if they are within five miles of an airport.  In some places in the country, like New York City or Florida, those five miles cover vast areas where people live, and apparently would even apply to toy airplanes in back yards or playgrounds.” But even assuming every comment on Regulations.gov was from an AMA member, that would still only account for 1.6% of the AMA’s membership.  Silence abounds.

Where are the drone users and model aircraft enthusiasts who have been so vocal in social media?  Is it possible they ? It’s a legitimate concern, just consider the fact that the FAA has spent the last few months cracking down on realtors.  Given such an enforcement climate, it’s understandable that some commercial users would not want to reveal their identity by commenting on a regulation.  Whatever the reason, what’s clear is that with just two weeks until the deadline, most drone users are sitting out this regulatory fight.

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