New site; UAVpilot.org gives me a mention!

I had an email from Thomas of UAVpilot.org;

Just wanted to say, I stumbled across your site earlier tonight and was really impressed with your do-it-yourself UAV project!

I've recently made a website, it's about...two days old now...but I hope you don't mind my doing a very small article on your project and providing a link, for anyone who might stumble upon me.

So I'm returning the favour with a link in the sidebar, looks like it could be a good resource... go take a look: UAVpilot.org

Landing gear almost done

All four retracts now have arms and swinging brackets that the vertical "foot" mounts to, complete with pivots and end stops. I think I might ditch the slider mechanism after all; save the added complexity for little gain. The polycarbonate arms provide a little spring anyway and I'm hoping to get soft controlled landings. Fixed vertical sections (the "feet" or "shins"?) are next, then the servos/mechs.

Keeping at it

No Worldcup for me, but I did spend a couple of hours tinkering in the garage. I discovered a minor issue with the gear retracts, but think I've got around it. I've worked on the second leg and cut some parts for the rear pair.

I've also been looking at PIC24Fs and will probably look at getting a couple of samples from Microchip. I'm also going to see if it's possible to home etch a PCB for a 100 pin TQFP with a 0.4mm pitch. I'm a bit rusty with PCB layout and C, but I'm sure it'll come back to me.

Longer legs and a blue ball

I've re-made the main arm of the L/G, making it longer and better positioned when stowed. I'm also half way through assembling the second leg (rear pair will probably have to be a different size). I'm having second thoughts about the sprung slider mech too; it adds complexity, weight and it won't even work too well because of the angle. Should I scrap it and go for a fixed lower leg? Would anyone notice? Would anybody care?

Notice the ball in the nose? That'll be the location of the pan/tilt camera and LED "searchlight".

Different angle of the longer leg, deployed.

The stowed position is much better and the wider footprint will improve stability.

Also, I was originally going to have the cargo ramp on the bottom, opening forward, but the L/G isn't going to give much room so I'll have to go for the traditional rear ramp under the tail.

One leg done, three to go!

I've fixed the slider to the pivot arm...

...and fixed the shaped vertical "foot"(?) to the slider mech, then temporarily fitted it into the airframe to test the fit. While I was at it, I clamped a servo in place and connected a pushrod to the retract control linkage, then plugged in the servo controller for a demo (see video, below).

Prototype L/G slider

The slider mech I mentioned in the last post, has to be lightweight and compact. I had come up with a possible solution, but it would've been a bit clunky. The alternative came from a sacrificial plastic vernier caliper that I got free, many moons ago, with some tech magazine. It's very light, free moving and ready made (kind of).

I'm interested in the centre sliding pieces. The cross-section shows the interlocking profiles that would be difficult to replicate by hand.

I hacked a mock-up and glued it to the gear arm, as proof of concept. There's a small spring fitted behind the slide that took around 1.5 kg quite nicely (there will be four of them). My concern is it may be too long to fit snuggly in the fuselage. Video below shows the proof of concept. Now I need to make it more robust.

Obviously, this will all be painted and disguised!

Landing gear prototype - video