SMALL - SMALL - Telemetry SMALL - Radio
benedict's blog
Posted by benedict | May 27, 2014 @ 02:19 AM | 1,198 Views
In an earlier post both to my blog, The View Up Here, and to my blog here on RCGroups, I described the design(ish) and build of a helmet cam with a reflex sight. Over the last few days I had the chance to take it out and use it on two separate occasions for two very different purposes. Here's how it went:

Outing #1: Documenting Kite Aerial Photography

(Bear with me... Some slope soaring happens in Outing #2.)

One of the reasons I built the helmet cam is that I want to document how I do kite aerial photography. There seems to be a lot of confusion when it comes to things like attaching the camera to the kite line, how the kite goes up the line (hint: it doesn't), and why KAPers insist on using single line kites instead of two-line or four-line kites. A good set of still photos or even a short video could answer most of these questions. I've tried photographing the process of doing KAP in the past, but without a second person to operate the camera it's just not possible. Enter the hat cam.

To try this I took it with me on a recent outing to the anchialine ponds near the old village of Wainanalii. The ponds are out in the middle of a lava flow, so the only way to get there is on foot. I parked my car off the side of the Queen Kaahumanu Highway and walked in.

A short way in off the road you run into the King's Highway. This is a trail system commissioned by King Kalakaua in the 1870s. Considering when it was built it's a...Continue Reading
Posted by benedict | May 21, 2014 @ 04:39 PM | 1,724 Views
This is a re-post from my blog, The View Up Here.

In an earlier post on The View Up Here I described a modification to my Turnigy 9XR radio that gave me two sticks that spring to center on both axes. This is necessary to set a plane up for 4-axis flying, and for that purpose it works great.

But what to do with my other planes?

Back when I originally wrote this article I had four airplanes in my hangar: the Le Fish - the one that prompted this change, a Zagi 5C flying wing, a Bixler 2 foamie, and a Raptor 2000 Advance. Ed Note: The Raptor has since gone to the great hangar in the sky, and I picked up a Phoenix 2000. I've been using the radio on my Phoenix the same way I did on my Raptor.

The Zagi 5C is a two-axis slope wing. It's strictly a "bank 'n yank" glider, and uses only the right stick on the transmitter. Changes to the left stick didn't really affect how the Zagi flies, so this required no changes to this plane's setup.

The other two - the Bixler and the Raptor - are motor gliders.

Despite the obvious differences - foamie vs. built-up, pusher vs. puller, x-tail vs. v-tail, etc. - from a control standpoint they're essentially the same plane. Each is a motor glider. Each has six control surfaces - two on the tail, two ailerons, and two flaps. And I have both set up identically. What works on one typically works on the other. Each needs to be tuned individually, of course. The tail on the Raptor...Continue Reading
Posted by benedict | May 21, 2014 @ 03:48 PM | 1,717 Views
This is a re-post from my blog, The View Up Here.

Le Fish
by TomBenedict, on Flickr

When I first ordered my Le Fish kit from Leading Edge Gliders back in March of 2013, I knew I wanted to set it up for 4-axis flying. In case the idea is as new to you as it was to me, this article should explain it:

Introduction to 4-Axis Flying

I highly recommend you follow the link, but here it is in a nutshell:

Most planes are set up with two or three axes of control: elevator (aways), rudder and/or ailerons. Powered models use the fourth joystick axis for throttle. Thermal gliders often use it for variable spoilers or some other form of airbrakes (flaps, crow, etc.) A four-axis aerobat is set up so the fourth joystick axis dynamically controls the camber of the wing by controlling the flaps or flaperons. Push up on the stick, the flaps go up, and the wing reflexes. Pull down, the flaps go down, and you increase the wing's camber.

The only catch with this is that you need the stick to move both up and down, and you need it to center automatically. The stick needs to spring to center on both axes!

And that's the real trick with 4-axis flying: you need a radio on which both sticks spring to center on both axes. Radios typically come with one of the sticks unsprung, so there's no way to do this right out of the box. It's possible to modify most radios to add a spring to the throttle axis, but I took a different route.

When I got my Le Fish (and Zagi 5C and Raptor 2000...Continue Reading
Posted by benedict | May 21, 2014 @ 02:18 PM | 1,511 Views
This is a re-post from my blog, The View Up Here.

This is the third and final installment of kite aerial photography articles. In Then and Now I described the evolution of my KAP rig from my first flight to the rig I use regularly today. In A Progression of Kites I described the additions I made to my kite bag over the years, and what those kites provided for in terms of KAP. This article describes my video downlink system.

The previous two articles were written almost as a history: "First this happened, then this happened." But over the years as I solved the various problems I ran into with my video downlink system, I wrote articles describing what I did. So the history version of this has already been written. Rather than repeat what I wrote, this article is more of a how-to for adding a video downlink system to a KAP rig. Note: It's also a good starting point for adding a remote viewfinder to an RC aerial photography platform, or for installing FPV on an RC platform as well.

In its very simplest design a video link is a wire that connects the video output of a camera with the video input of a display device. It's possible to set up a KAP rig this way, but the wire would have to be long, heavy, and would be a nasty thing to have in your hand when lightning strikes. For obvious reasons, it's preferable to send the video signal to the ground some other way: radio.

It bears mentioning at this stage that unlike a wire, leaping into the world of radio...Continue Reading
Posted by benedict | May 21, 2014 @ 02:04 PM | 1,464 Views
This is a re-post from my blog, The View Up Here.

In my previous post I gave a bit of a history of the cameras and gear I use for kite aerial photography. But I left out the most important part of KAP: the magic levitation machine that makes the whole thing go. The kite.

Something I didn't know when I first got into KAP is that while any kite can lift a camera, you don't use just any kite to do KAP. When I ordered that first Brooxes BBKK kit years ago I thought I had a good lifter kite. It was big. It had pull. Perfect, right?

As it turned out, no. It was a big parafoil with the most amazingly complicated bridle I'd ever seen. I never could quite get it in tune. The kite did fly. I can attest to that. But if the wind dipped even slightly or gusted, it would quit flying. And sometimes it would overreact to a wind shift and just take off sideways. It was fine when all I was doing was flying it as a kite. But for KAP it was frustrating!

Turns out the kite had an amazingly narrow wind range. Wind Range is the term used to describe the wind speeds a kite can operate in. There are a couple of reasons why you want kites with wide wind ranges when doing KAP.

First, the wider the wind range on your kite, the fewer kites you need to cover a range of speeds. Say you have a bunch of kites that can handle maybe 4mph difference in wind speed. To cover everything from 5mph to 25mph, you need five kites. You could cover that same range with three kites that have a broader...Continue Reading
Posted by benedict | May 21, 2014 @ 01:45 PM | 1,367 Views
This is a re-post from my blog, The View Up Here. This article describes aerial photography using a kite as the camera platform. It's a different approach than most of the aerial photography on RCGroups, but much of the technology, artistry, and technique applies equally to both.

I recently did a KAP session that brought me back to my first experiences with kite aerial photography. For anyone who reads my blog, some or all of this will be old hat except for the bit at the end. Feel free to skip ahead. If this is your first exposure to kite aerial photography, I hope the following doesn't bore you to tears. There's a fun story here.

Back when I first started doing kite aerial photography, I used a Nikon Coolpix 5600 in a Brooxes BBKK rig. I initially bought all the bits for a bare rig, but after my first couple of flights I ordered a leg kit and a set of PeKaBe blocks. This whole mess was driven by an ancient Futaba 72MHz radio, and had to be aimed "blind" by looking at the camera, looking at the subject, tripping the shutter, and hoping.

Despite the way that sounds, it worked great. I learned how to fly. I learned how to aim. I flew every chance I had, and produced a lot of good photographs. I had more hair back then, too, and most of it hadn't turned gray yet.

by TomBenedict, on Flickr

Kids and time took a toll on the hair, and sometimes the KAP contributed to the graying process as well. But it was a...Continue Reading
Posted by benedict | May 20, 2014 @ 08:41 PM | 1,823 Views
This is a re-post from my blog, The View Up Here.

The biggest problem with most hat cams or helmet cams is that there's no way to aim them accurately. In a post on The View Up Here I mentioned a project to attach a reflex sight to a helmet camera to give me some way to keep the camera aimed at the subject. To that end I ordered a reflex sight and a Picatinny / Weaver rail to mount it on along with a Gopro Frame mount. All the bits and pieces have arrived, so I started designing. Then I realized this is really a scrap box project: the design and build phases are really one and the same. So I started over with the bare bits I wanted to stick on the helmet: a Gopro, an A2200, and a reflex sight, and got busy.

Reflex Sight:

The reflex sight has nearly zero magnification and projects a red dot into your field of vision as if you had a laser pointed out at the landscape. The idea is that once the sight is dialed in, the center of the frame of the camera will lie where the red dot points.

The dot is projected out at infinity, which explains the reason why I couldn't get the dot and the body of the sight in focus at the same time. (Dang limited depth of field!) Even though this one was made for a firearm, reflex sights like this have been used as wide field finder scopes on amateur telescopes for decades. Adapting one to this application seemed reasonable.

Camera...Continue Reading