One More Try at Lancaster Park

I decided to return to Lancaster Park again. If you read my last post, you’ll know that I had a lot of lessons learned. The purpose of this session was to try to incorporate some of those lessons. Plus, I knew from my first time out that looking north from this park had the potential to produce some nice views of the Patuxent River and Gov. Thomas Johnson Bridge crossing the river, so I’d use this session as an opportunity to take pictures in that direction.

The main thing that I wanted to try this time was attaching the camera after that kite was already flying steadily, rather than attaching it to the line on the ground. I had learned by now that having the camera hanging very close to the kite makes it less stable, and trying to launch and land the kite with the rig still attached is just asking for trouble. (Read my previous two posts for all the juicy details. 🙂 )

The wind was from the west this time, so I flew my Mini Dopero kite from a soccer field on the north side of the park, which runs east and west lengthwise. The wind strength was marginal for this kite, and it took me a couple attempts and bridle adjustments to get it in the air, and I was thankful that the camera rig wasn’t attached during the failed attempts. Finally, it was in the air flying pretty smoothly on about 100 feet of line. I didn’t have a way to secure the line while I attached the rig, so I resorted to putting the winder on the ground and standing on it. That was a little awkward, but eventually it worked. (For future sessions, I filled a duffel bag with rocks to take care of the line-holding duties.)

With the rig now attached to the line and the KAP UAV intervalometer script running, I grabbed the winder again and began letting out line to lift the camera higher. It was slow going. Besides the wind being just barely strong enough, the bridle might have been adjusted with the tow point a little too far forward still, because the kite just wasn’t pulling very much. I eventually coaxed it to a few hundred feet in the air, but with the weight of the rig and the line already out, it wasn’t going to get any higher than that. This was one day that would have been perfect for a bigger kite like the Barn Door, except I hadn’t built it yet!

View looking north from Lancaster Park, with the Patuxent River and Gov. Thomas Johnson Bridge in the distance

This certainly wouldn’t be a day for high-altitude pictures, but I was still very pleased with the results. The new things I had tried worked. Attaching the camera well below the kite and using a faster shutter speed resulted in a high percentage of the photos being sharp and close to level. Angling the camera view down a little bit resulted in having more ground in the frame while still being able to see off to the horizon, and the exposure was correct in most of the shots. The picture above is probably the best one of the bunch. It’s not that high, but it’s level (I rotated it just 2.5 degrees in GIMP), sharp, and shows a little bit of the park and also the surrounding area, including the Patuxent River and Gov. Thomas Johnson Bridge. It’s the first of my kite aerial photos that I think is deserving of the watermark down in the corner. 🙂

Are you getting bored of this park yet? I am. Next time out, I’ll try somewhere else.

Lancaster Park – Take Two

One week after my first KAP attempt, I returned to the same park with 200 more feet of line (for 700 feet total) and a new camera — a Canon PowerShot Elph 160. It was equipped with a simple intervalometer script provided by CHDK. The goal this time was to get the camera as high as possible to see what the landscape looked like from hundreds of feet in the air.

Despite my stability struggles the last time out, I decided to still attach the rig to the line while the kite was on the ground and do a long-line running launch to get it in the air. I did attach the rig a little bit farther down from the kite this time to hopefully improve the stability a bit. Another change was to point the camera level with the horizon, since the goal was to see far off in the distance.

The launch went a lot like the first time. There was even less wind though, so I had to run the whole length of the soccer field while letting out line until the kite was away on its own. About halfway through the run it started to descend again, but it was saved at the last second by a gust of wind that lifted it into stronger air. The sequence of images at the right illustrates the harrowing experience!

The flight itself went pretty well. I managed to get all of the line out, which promised to return some very high-altitude shots! Being a warm summer day, thermals abounded, and several times the kite got lifted up in them. Bringing the kite down, I struggled with the line angle becoming very high. That’s not uncommon when winding in a kite, since the line tension increases as it is wound. But combined with the thermals and the fact that the kite was less stable with the rig so close to it, it became a bit stressful, since the kite seemed to want to be directly overhead. I started getting worried that it would dive into the trees on one side of the field or the parking lot on the other. I decided to put down the reel and try to just walk the line down by hand as quickly as I could to reduce the chances of the kite crashing somewhere other than the soccer field where I was flying.

This strategy was somewhat successful. While the kite didn’t crash into a tree or the parking lot, it did crash in the field. Once it was below treetop level, the wind became light and variable once again, and the kite started to dive when it was still 50 – 100 ft above my head. It ended up going in nose first, with the rig crashing into the grass in front of it. Thankfully, the ground was soft, and the camera and kite weren’t damaged at all. The rig did sustain some damage though, since it took the brunt of the impact when it came down. The bottom part of the frame came unglued along two edges; nothing that can’t be repaired!

View looking south towards St. Mary’s City

The pictures themselves turned out a little disappointing. They were definitely high, but the quality wasn’t as good as I had hoped for. I realized that this was due to a few problems. First, the shutter speed wasn’t fast enough. The maximum speed was less than 1/1000 sec, which resulted in a lot of the pictures having motion blur. Second, the camera being attached very close to the kite, which meant that any motion of the kite was transferred right to the rig. Having a relatively slow shutter speed only made that worse. Third, with the camera pointed level, the it had to keep adjusting the exposure as it swung towards the bright sky and then the darker ground below. As a result, lots of the photos were overexposed or underexposed. And finally, I was trying to take pictures towards the sun, which just made properly exposing the photos more difficult. A couple of the pictures did turn out okay though, as you can see above and below.

View looking southwest towards Great Mills

So, even though the pictures didn’t come out quite as nice as I hoped, I learned a lot of things from this session:

  1. Fly the kite first, then attach the rig at least 50 feet below, while the kite is already flying. This way, the rig doesn’t significantly affect the stability of the kite, the camera moves around less, and there’s not as much worry about it crashing into the ground while the kite is being let out or brought back down.
  2. If using a camera without built-in shutter speed control, use the KAP UAV Exposure Control script in CHDK to make sure the shutter speed is 1/1000 sec or faster.
  3. Even when taking landscapes off into the distance, it’s best to angle the camera down at least 10 degrees. That way, you get more ground than sky in the shot, and the camera will struggle less with constantly-changing light levels.
  4. Generally speaking, it’s better not to take pictures towards the sun. The subject will be shadowy and the sky overexposed. If you are using a good camera (particularly one that can save RAW images for editing later) and you know what you are doing, you can still get good results, though.

My First KAP Session

The day had finally arrived. I finished building my Mini Dopero kite a little over a month before, and now I’d finished building my first picavet rig to lift an old Android phone up into the air. I’d flown the kite several times by that time and was feeling pretty confident with it. The phone was all set up with the Open Camera app, which seemed to work fine on the ground. And today there was a nice south breeze of about 10 mph, which would lift the kite right above the baseball and soccer fields at Lancaster Park in Lexington Park, Maryland.

My first time out doing KAP, I was a little hesitant to try to attach the rig while the kite was already flying. For one thing, I didn’t have a good way to hold the line down while I worked on the rig. For another thing, it just seemed like too much to manage at once for a beginner like me. So instead, I set up the kite and laid out about 100 feet of line for a running, long-line launch. I attached the camera and rig while everything was still on the ground. In retrospect, it was kind of amazing that this worked. (It’s definitely better to get the kite flying up in smooth air first, then attach the rig. There’s less that can go wrong. To hold the line down, now I just use a backpack filled with a bunch of rocks. A primitive but effective solution!)

The Mini Dopero lifting a rig during my first-ever KAP session

Prior to attaching the rig, I had flown the Mini Dopero for a few minutes to make sure it was all trimmed out. Then, with it laying on the ground, I attached the picavet to the line only about 10-15 feet below the bridle. I put on my gardening gloves to protect my hands, walked back to the winder, and started simultaneously pulling, running into the wind, and letting out line. The kite took to the sky, smartphone in tow. The wind was a bit light and variable at ground level, so I wasn’t totally confident that this would continue to work once I stopped running. As luck would have it, right about the time I had run the whole length of the soccer field and was coming up to a row of trees, the kite contacted some stronger, steadier air above treetop level and was now rising by itself.

One thing I found out quickly doing this approach was that, with the camera attached so close to the kite, the kite’s trim was considerably different. The weight pulls down on the line above it, increasing the line angle that the kite experiences, which lowers the angle of attack. That in turn reduces the lifting force and makes it a bit less stable, especially near the ground where there may not be a sufficient steady breeze to keep it flying. That resulted in an “interesting” landing with a couple cartwheels involved! (No damage though, thankfully!) That’s yet another reason that the rig should be attached once the kite is already flying, on at least 50 feet of line.

All told, I ended up with at least a few nice pictures from the flight, some from a few hundred feet up in the air. I was quite pleased with the results for a first attempt. Here are the ones I liked the best. My next goals are to get better at attaching the rig and flying the kite, and also to get a better camera.

The dog park and fields adjacent to the flying site
A view of Lancaster Park and Great Mills, Maryland from a few hundred feet up
The kite swung east, giving a view of the softball field, Lexington Park, Maryland, and Gov. Thomas Johnson Bridge to the north