Old Man Mike

Although I have the SAVS DF system, I thought it might be fun to see what could be done with a Panasonic DMC-FX07 Digital Camera. The features of this little 7 Mpixel $250 camera are:

- 5.6 oz with battery
- Two modes of gyro based antishake processing
- 3072 x 2304 stills and 848 x 480 30 fps 16:9 video
- MOV format for minimum compression (basic jpeg frames)
- 2 GB SD card allows >20 mins of 16:9 video or 550 max size stills

The first picture shows the small pouch with quarter inch foam that a family member made to carry the camera on the DF. The battery is used as an offset weight by attaching it to the side cross brace. The total added weight was aprox 7 oz.

Here's a video showing the DF flying with the pouch but without the camera. I could tell little difference in the flying compared to the normal DF:

[link=http://www.af9y.com/DFfly.wmv]Flying Pouch[/link]

Next, I tested the antishake mode on and off in a controlled indoor DF flying test. It appears to do fairly well:

[link=http://www.af9y.com/AntiShakeOff.wmv]AntiShake OFF[/link]

[link=http://www.af9y.com/AntiShakeOn.wmv]AntiShake ON[/link]

Here's the first outdoor video flight production (more of a fast slide presentation). There was a 5 mph wind and TI was OFF so there was a little more movement than I would have preferred. I can certainly tell the difference flying with the camera but was able to get it up to around 100 feet and bring it back down for a safe landing:

[link=http://www.af9y.com/DFsky.wmv]Fly Away[/link]

Finally, I've included one of the best stills from the video (slightly reduced in size because this forum limits the width to 800 pixels)

Mike

BB_DF

Mike,
The antishake really works on that high-frequency vibration from the motors. Were you flying without Ti on? Sounds like your photographer was getting a little jumpy! I've been concentrating more on climb-and-pan shots without too much horizontal travel over the ground, since the wind got the thing away from me a couple of weeks ago. I flew it about an hour yesterday practicing parking it about 100' up, and trying to get more sensitive to it drifting one way or the other. It's actually pretty cool to see it sitting up there for 8 minutes like some kind of alien drone. Good clarity in those aerial shots, and I'm amazed at the quality of the still considering it was from a video. Did the DF seem to be struggling with the extra weight?

Cheers,
Bruce

Old Man Mike

Bruce,

Thanks! Yeah, my wife has seen me crash it a few times so she did not like me getting it too close to her [X(]undefined. Except for a few tests, I've always flown the DF with TI OFF. You can see from the video that I'm surrounded by trees and maybe that is confusing the TI. My second receiver card should be in next week and I'll see if it behaves any different. At this point, I've flown so much without TI that I may actually be less capable in my flying with it ON. I'm also a little worried that the TI may be tuned for the lower weight without the camera. I have some dummy weight for the pouch and will test it more before I allow it to be enabled with the camera.

And yes, it feels heavy when flying with the camera. I noticed the biggest change when bringing the DF down. The rhythm is different and requires a heavier response on the throttle. But it is not hard to get use to. There is another benefit of flying with the camera. When I go back to flying without it, my flying capability seems to improve trememdously. It is like swinging with the three bats in warm up and then going back to one bat.

Mike

Sky High

Yes, that was kind of funny. Great job, especially without Ti! On clear, calm days has Ti acted up in that open area? I've had Ti act strange in a ballpark with a 100 yard radius surrounded by trees. Once I got above the treeline though it became smoother. Have you tried to calibrate on the concrete?

BB_DF

Mike,
What receiver card? How is that related?

The Ti doesn't see trees because they're pretty neutral in temperature. However if they're thick enough, they will blur the horizon. Seems like your environment would be the perfect place. Even if you're pretty close to a building when you set the level (down-right throttle), usually all it needs is a lot of cyclic trim to make it behave. Setting the thermal level is probably the most crucial part of making it work, and whatever it "sees" when you do it is what it thinks the world looks like in terms of a horizon. Today after I armed it with Ti on I tried holding it up over my head as level as possible, and setting the level on the transmitter with my left hand. It seemed to work better than setting the levels on the driveway and having it get confused by a hot engine block or house nearby.

One thing about having Ti enabled, is that it ALWAYS takes off weird. It will flop around on the ground, but as soon as you goose it a little, it will stabilize very quickly in a shoulder-high hover. However, one might presume it's not working correctly and thus not want to lift it up quickly - it takes a bit of faith. On real helicopters you have to very slowly get the aircraft light on the skids, and lift off very carefully to avoid dynamic rollover. On models, however, it seems you need to lift off smartly to get out of all the disturbance near the ground.

The most critical thing about Ti is that the higher you get, the better it works, as Sky High said. Notice that LaceyCopter said she doesn't fly with Ti on, but she said she never flies very high. This is a key point. I practice with Ti off every day to improve my skills, but I don't see any possible way that I could have survived 7 or 8 hours of video time so far without it. At 100 or 200' hovering, all kinds of weird optical illusions start to play tricks with your eyes. You know how much input it takes to keep the DF in a low hover, imagine trying to determine if that tiny square in the sky is level. Going into a spiralling dive from that altitude would be difficult to recover from. Odds are if you were disoriented enough to initiate a dive, things are not going to improve on the way down. I've put the DF into a spiral dive by accident, and it leveled itself immediately when I centered the sticks. I'm coming at this from the perspective of trying to teach a bunch of Sheriff's deputies how to fly - and have the SAVS survive the first mission!

Doing good, though, keep it up.

Cheers,
Bruce

Sky High

My theory on the trees in an enclosed configuration is that they are acting as a bowl trapping warm or cool air, whatever's opposite to the sky, near the ground like how fog is formed and that is what is confusing the Ti sensors. However, I have successfully flown the DF in thick fog before in an concave field. That was very cool because the DF had several different color LEDs on it whose beams cut through the fog. [8D] When in that field surrounded by trees that I described, the DF flew like it would on a cloudy day, really loose. But once above the treeline it became solid.

Speaking of nose dives. [link=http://www.rcuniverse.com/forum/fb.asp?m=4159405]Here[/link] is one that I captured from the DF POV a while back. [X(] If it wasn't for Ti, I don't think I would have recovered because all I did was apply throttle and it leveled the DF out so I could get control of it again.

BB_DF

Uh-huh. You've probably got two or three entries in whatever's the current version of Project Blue Book.

In your video you can see the onset of vortex ring state, and one rotor's lift collapsed. You have to demonstrate that phenomenon (and how to recover from it) on your helicopter check ride. It's like "This maneuver will kill you, kid. Here, let me demonstrate."

OK, I give up. What does POV stand for?

-BB

Sky High

I don't know about that but some cute college girls did come down to see what I was up to.

[link=http://www.rcuniverse.com/forum/fb.asp?m=4191489]Here[/link] is a some AP video of that bowl I was flying in.

That stands for Point of View.

What is vortext ring state?

My freefall was self induced to lose altitude faster because as you may well know it sometimes seems like an eternity for that thing to descend from high altitudes. I won't do that again with a SAVS because of the unequal weight on the side of the battery. That's what caused the steep nose dive when the power was cut. The DF will freefall more horizontally when the battery is centered under the flight board. What's really cool in a level freefall is that the rotors begin to spin backwards!

BB_DF

Vortex ring state (also called settling with power) occurs when the heli is descending vertically without much forward air speed. The rotor is trying to produce lift, but it is descending into its own turbulence, and starts to create vortices around the blades. If you imagine a rotor spinning inside a box, you will see that the rotor will not produce lift because pretty soon all the air in the box is just rotating around with the blades in a vortex, or donut. All you have to do is fly forward, out of the vortex and get clean air passing through the rotor again. Adding power without forward cyclic just makes the matter worse. That is what caused that really bad V-22 Osprey Tilt-Rotor crash some time back. The computer sensed that one of the rotors was losing lift, and added more power, which caused it to lose lift completely. They've now reprogrammed the computers to recognize the approach of the condition and alert the pilot to either decrease descent or increase forward speed. (Software - ain't it great?)

Old Man Mike

Thanks for the feedback, guys.

BB_DF: I should have called it the DF circuit card assembly which controls the motors and carries the thermal sensors and receiver.

BB_DF & SkyHigh on TI:

I need to do some more testing. I have flow with TI enabled a few times without too much erratic operation but it felt much less responsive, which I guess makes sense. Since I am completely surrounded by trees, it makes me think that it is having difficulty getting a good definition of ground. If even one direction was free of trees, it might do better. I will also try it on concrete but that area is close to the house and a tree. I can certainly see the advantage of being able to have TI enabled at the high flying levels. It does get hard to keep the right perspective.

BB_DF: I had someone in law enforcement ask me about the DF, training, etc. I gave her your name and this forum as a place to contact you.

This stuff sure is fun for experimenting. I have been looking at removing the camera battery and building a cable interface/regulator to run it off the DF battery. That would save almost an ounce of weight. Also, the styrofoam that someone else was using might be better than the foam. I really should try out the SAVS camera and floating mount. I've been enjoying reading about your modifications there also.

Mike

BB_DF

Yes, a common problem. As some of us have discussed here, there's way too much slop in the controls the way it's set up. Try setting the EXPOs to 20% on the upper D/R position. It sounds to me like it's working. You just have to learn how to use it to your advantage.

I'm starting a new thread so that we can exchange ideas on this subject...

We've had several interesting exchanges!

BTW, at some point I'm going to buy another control board too, just as a backup. Spectrolutions can also sell you a spare.

- Bruce