Flights

December, 2018

The video below uses PanCam version 1 (with plastic camera case and plastic tripod mount base) for the first time. As you can see, vibration remains a big issue, which I hope version 2 (all metal connections, detailed below) helps mitigate. Further results will be posted here when the flying season resumes in 2019.

This is version 2 of my 360 degree panning camera mount, which is now a wireless, self-contained, 9-volt battery-operated unit -- no more mounting location limitations due to the previous version's long power cable that had to be plugged into my 12-volt instrument panel.

These are all the parts. The 12-volt DC, 2 RPM gear box motor, with 6 mm output shaft, came from Amazon seller BBQ Driver. All the other parts were similarly searched for and found on Amazon, except for the nylon washers and compression spring, which came from the local Ace Hardware store. For complete rigidity, all flexible, vibration-promoting, plastic camera supporting parts were replaced with metal versions, namely the GoPro- style tripod mounting base and camera case. The motor's output shaft attachment to the base is completely rigid and flex-free. The compression spring pushes up on the bottom of the aluminum tripod  base joint, removing vertical play in the out-put shaft, which,	if left untensioned, would allow the camera to vibrate vertically. Unfortunately, the 1 degree or so of rotational play, due to gear lash, isn't dampened by the spring, so the camera is still able to rotationally vibrate, which can create "jello" video at certain engine RPMs. The 9-volt battery case is attached to the motor's gear box with 4-40 pan head screws and nylock nuts (the gear box is easily disassembled for internal access). 1/8" holes were drilled in the side wall of the gear box, located so that the nuts would not touch any of the gears. The micro project case is hot melt glued to the battery case and the RF remote control receiver  circuit board is hot melt glued inside.
As with almost all the parts shown, the RF remote control bi-directional switch is made in and shipped from China. With the antenna not extended, the range of the remote is over 200 feet, far more than needed for its close-range use of not more than 15 feet. Tapping the Up or Down buttons on the remote turns on the motor. It will run continuously in one direction or the other until the middle Stop button is pressed. The motor draws a minuscule 8 mA of current, so it will run a long time on a 9-volt battery!
The PanCam, mounted to my DIY anti-jello vibration mount, using a SmallRig Clamp mount. The clamp comes with a 1124 ball socket, which I replaced with a more robust Panavise 851-00. The plastic, anti-mar grip pads on the inside jaws of the Panavise clamp were removed, in order to make the clamp's attachment to my ultralight's tubular elements even more solid and rigid. The camera's OEM plastic case was replaced with a CNC milled Aluminum case specific to the brand and model of camera used. Both types of cases have around 0.25 mm of internal clearance, in order to make it easy to insert and remove the camera. However, this tiny gap allows the camera to vibrate inside the case and is another source of "jello" video. To prevent this, a strip of milk carton cardboard, bent in an L shape is used to wedge the bottom and side of the camera firmly against the opposite sides of the case.

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July 3, 2016



The Skyhopper flies GREAT, now that she's painted and trimmed! Now it's on to building and testing anti-vibration GoPro-type camera mounts.

The one used in the video above is shown at left. It was mounted to the end of a 5-foot long tube bolted to the wing tip spar. Although Sorbothane, a polyurethane rubber with self-adhesive properties (that is, it's sticky) is touted as the best vibration dampening material of the century, it just doesn't have the necessary range of motion to absorb high-amplitude macro vibrations (eg. engine at idle rattling through the entire airframe). Thus, the resulting video is not entirely satisfactory. What Sorbothane is better at is dampening out most of the jello-forming, high-frequency, low-amplitude micro vibrations.

During development and testing of this mount, I started out with full discs of Sorbothane, in which I cut out a 1/2" hole in the center to accommodate the 1/4"-20 threaded rod that joins the top and bottom plates together. For the next test I added lead discs to add mass to the camera side of the system in order to lower the resonate frequency of the mount in an attempt to get it below the "rattling" frequency of the idling engine. This didn't work as desired, either, so I cut larger holes in the Sorbothane pads, first a 1" dia. hole, then a 2" hole, turning the pads into rings. This helped a little bit more each time, but still the mount was unable to deal with the high-amplitude, low-frequency vibrations.

The next anti-vibration camera mount I'll be investigating uses four short wire rope segments to join two X plates together. This design appears to handle both types of vibration and amplitudes and is used for professional camera rigs mounted to vehicle exteriors, usually in conjunction with a gyro-stabilizer. The question is:  how well will it resist a 50 mph wind? That is, will the camera flop and wobble around?
UPDATE: September, 2017 - I decided to purchase the real deal. I bought FlightFlix's VibeX vibration isolating, anti-jello camera mount with their Rock Steady ball socket and a heavy-duty tube clamp made by Small Rigs. Still testing it out.

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February 19, 2016

Wing carrier fabrication and installation on my 5x8 utility trail completed on Feb. 12.	1/2" thick grade F13 felt pads glued to the bottom cradles and top keepers Feb. 17. Ready for transport!
And the whole thing just barely fits in my 2-car garage. I have to keep the nose of the plane raise up about a foot, lowering the tail, so that the folded up stabilizer fits under the garage door.	Colors look good, yes?
	Overall, this plane has been a pain and a pleasure. The pleasure is in fabricating and assembling stuff. The pain is in little mistakes here and there and how much more work it will be to transport and set it up compared to the old way of just bundling up each wing's LE and TE, "folding" them back parallel to the boom, wrapping the wing sails around them, resting it all on the fixed, straight stabilizer LE, and securing with bungee cords. Time will tell if flight performance was worth all this effort and time... 2 years start to finish... Wow! I have a painful, sinking feeling it will be less than expectations, based on how different it felt during the maiden flight compared to its slower, draggier, lighter, easier-to-setup former self.

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November 28, 2015 (updated Jan 28, 2016)

Here's the maiden flight! The air was about 7-10 mph at 300 AGL, so it was a little bumpy and "swayey" so I purposely kept her low. Remember, it was 5 years since I last flew, so I wasn't comfortable being jiggled around up there.



Take off: ~35 mph
Cruise: ~50 mph @ 5,200 rpm
Stall: ~ 30 mph
Handling: I was being conservative on this first flight around the pattern and so was varying the throttle to find out how she responded. I found that she needs about 500 more rpm than her previous incarnation as a Weedhopper to maintain altitude. Anything less and she started to sink. She also required significant up elevator. Letting the stick go to neutral resulted in a nose dive.
Update: After several modifications, especially adding a gap seal and finish paint, this plane is now a dream to fly! No ill handling, LOTS of lift, trimmed for hands-off level cruise of 50 mph @ 5,200 rpm, and at take off, she climbs like a rocket at WOT (6,100 rpm). The characteristic nose dive on power off effect is minimal with this wing.