First KAP With 2.5 Meter Barn Door
by Dan P
(Lexington Park, MD, USA)
Based on your flight reports with the Multi-Dowel Barn Door kite and my previous success with a scaled-up version of your Dopero, I decided to build a 2.5-meter barn door kite.
The main purpose of this kite was for kite aerial photography (KAP) in lower winds than my Dopero is capable of. I sewed the sail out of 0.75-oz, neon blue and yellow ripstop. Each of the three spars is made up of 3 Skyshark P4X carbon tubes, 32.5 inches each, for a total length of 97.5 inches (2.5 meters). So it's actually just a little bit bigger than the MBK Multi-Dowel Barn Door kite.
The total weight of the kite, including the bridle, is 18 oz (510 grams). For size reference, a picture of 6'2"-me next to the kite is included.
There is one other departure from the original design, in that I've added a small keel on the lower half of the kite to serve as the bridle attachment point. Plus I figure it might add a little bit of stability too.
I had done a couple test flights in an open space in my neighborhood earlier in the week. The weather forecast called for 11 mph winds on Saturday morning, which I figured should be within the kite's range, even though it wasn't a light wind. When I got there, it seemed to be actually a little stronger than that, with gusts up to at least 15 mph I would say.
Despite my concern that this wind might be too strong for the kite, I decided to give it a try anyway. "What's the worst that could happen," right?
Well, the kite definitely exceeded my expectations. The strong gusts were mostly absorbed by the flexibility of the spars and the lower half of the sail billowing. My Dopero would have really struggled with this wind, because, being stiffer, the gusts would have caused it to surge straight up above my head or off to one side or the other.
During times between gusts, this kite was a real pleasure to fly. At one point, it found its way into a large thermal, as indicated by the high line angle and the vulture that joined it to soar! When the thermal died down and tension in the line was lost, the big kite just floated backwards downwind until tension was restored.
In general, the wind was quite variable, and I found myself walking from one side of the field to the other to try to keep the kite away from the trees on one side and the cars in the parking lot on the other. This was fun but a little stressful with a new kite!
After a several minutes of flying, I decided to attach my KAP rig and see if I could get some aerial pictures. I wrapped the line around both carabiners at the end of my homemade picavet rig, started the intervalometer script, and sent it up.
I have a small Canon Powershot camera from around 2010, which has been loaded with CHDK custom firmware called CHDK. I am also using a script specifically designed for KAP that functions both as an intervalometer and an exposure controller, to make sure the shutter speed stays nice and fast.
It was a very successful session. One of my favorite shots is included below, as well as a photo of the kite, drogue, and rig from the ground, which was tough to get since the sun was directly behind the kite a lot of the time.
Thanks for another great kite design!