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Old Nov 30, 2012, 02:22 PM
Lift is cheap - Drag sucks
Tom Harper's Avatar
Socorro, NM
Joined Jul 2004
3,664 Posts
System development

Hmmm..as soon as I let go it went into a loop. Not enough airspeed for control. Powell cut the throttle (kept it from hitting me in the back of the head) and it boinked into the ground. The motor mount is pinned into the plywood keel and it separated clean so repair is simple.

Looks like the problem is the low thrust line - 1.5" below chord line. That and the significant increase in thrust with the 10x6 prop. So it shouldn't be too tough to raise the motor and try again tomorrow.

Second problem is that the camera shuts off if it sits 5 minutes without taking a picture. The Lumix does not address the feature in the specification or manual and there is no menu item to turn it off. So, I'll have to rig a processor to keep it on.

Tom
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Old Nov 30, 2012, 02:35 PM
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Blacksburg, VA 24060 USA
Joined Feb 2000
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On the Other Hand...

Gents,

Putting aside my remark re wheel reinvention, I am looking for a way to reduce breeze-induced roll jitter of the wide-chord Slow Stick wing. Yes, some autostabilization would probably help reduce wing wobble to varying degree. But I also figure that a new wing of wider root chord and reduced tip chord would also help alleviate the problem. Or perhaps a pure delta wing.

Thoughts? Is this part of Tom Harper's thinking?

Jim R.
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Old Nov 30, 2012, 02:36 PM
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Sparky Paul's Avatar
Palmdale, CA
Joined Oct 2000
13,499 Posts
Does the Lumix have a time lapse feature?
The GoPro has a selectable interval, from every 1/2 second to 1 a minute.. and a One-button turn-on. Start it, toss it, land it, turn off the camera.
And it can invert the image if the camera is mounted upside down, as I've had to do to get the lens outside the fuselage... the camera has a 110 degree FOV.
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Old Nov 30, 2012, 03:30 PM
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Palmdale, CA
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Quote:
Originally Posted by JRuggiero View Post
Gents,

Putting aside my remark re wheel reinvention, I am looking for a way to reduce breeze-induced roll jitter of the wide-chord Slow Stick wing. Yes, some autostabilization would probably help reduce wing wobble to varying degree. But I also figure that a new wing of wider root chord and reduced tip chord would also help alleviate the problem. Or perhaps a pure delta wing.

Thoughts? Is this part of Tom Harper's thinking?

Jim R.
.
The dihedral causes the roll oscillations. You might reducing that a bit at a time.
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Old Nov 30, 2012, 03:32 PM
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Sparky Paul's Avatar
Palmdale, CA
Joined Oct 2000
13,499 Posts
Quote:
Originally Posted by Tom Harper View Post
Hmmm..as soon as I let go it went into a loop. Not enough airspeed for control. Powell cut the throttle (kept it from hitting me in the back of the head) and it boinked into the ground. The motor mount is pinned into the plywood keel and it separated clean so repair is simple.

Looks like the problem is the low thrust line - 1.5" below chord line. That and the significant increase in thrust with the 10x6 prop. So it shouldn't be too tough to raise the motor and try again tomorrow.

Second problem is that the camera shuts off if it sits 5 minutes without taking a picture. The Lumix does not address the feature in the specification or manual and there is no menu item to turn it off. So, I'll have to rig a processor to keep it on.

Tom
.
Those first flight W!!!!*&^%! are why I've gone to landing gear on some planes.
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Old Nov 30, 2012, 03:47 PM
Lift is cheap - Drag sucks
Tom Harper's Avatar
Socorro, NM
Joined Jul 2004
3,664 Posts
Agreed...but with this one the LG was the problem aaarrrrgggghhh!

Tom
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Old Nov 30, 2012, 03:51 PM
Lift is cheap - Drag sucks
Tom Harper's Avatar
Socorro, NM
Joined Jul 2004
3,664 Posts
JR,
Sparky's got it - reduce the dihedral a little at a time.

Auto stabilizers won't help because they do not null. They are always hunting a bit in roll.

Tom
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Old Dec 01, 2012, 04:47 AM
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You should also check if some resourceful hacker has come up with firmware modifications for the camera. I know of several models where their firmware was modified for tasks like time lapse photography, or to take high speed footage.
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Old Dec 01, 2012, 10:24 AM
Registered User
Blacksburg, VA 24060 USA
Joined Feb 2000
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Gents,

Thanks for your help. Reduce dihedral, be skeptical re ought-to-stabilization.

Jim R....
... whose own stability is somewhat in doubt...
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Old Dec 02, 2012, 01:10 PM
Lift is cheap - Drag sucks
Tom Harper's Avatar
Socorro, NM
Joined Jul 2004
3,664 Posts
Brandano,

I've done that with Canon, but Lumix does not have any hackers firmware.

Tom
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Old Dec 02, 2012, 01:28 PM
Lift is cheap - Drag sucks
Tom Harper's Avatar
Socorro, NM
Joined Jul 2004
3,664 Posts
Development

Turns out that the camera allows 5 minutes before it shuts off. With a bit of organization it' s easy to get this thing buttoned upa nd in the air in less than 5 minutes.

Rigged a qiuick fix of a plate bolted in the old mount holes to raise the thrust line. Decided to go ahead and try it on our survey site. Programmed a loiter circle around the launch site for 2 minutes, so if that was OK it would go ahead and fly a few waypoints to test the camera and autopilot.

All went very well for an initial flight. It's very easy to transport and set up and it looks great in the air. Did not get stall speed and max speed but did get some data:

9 Amp cruise current @ 60 kmh

100W Cruise power

Cruise range 21 kilometers

The goal was less than 8 Amp cruise. It did have considerable roll oscillation. I'll clean up the mount and move the CG back then work on the oscillations.

Camera is not bad for a start. I thought I had sealed the lens tunnel but some scraps found their way in. Also the camera angle is a bit steep. The photo was taken on the climb out. The detail was cut from it.

Tom
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Old Dec 04, 2012, 06:34 PM
Lift is cheap - Drag sucks
Tom Harper's Avatar
Socorro, NM
Joined Jul 2004
3,664 Posts
Development

Filled in the plywood keel and mount plate with balsa blocks then shaped them with a sanding block. I'll cover them with silkspan and polycrylic and let it set up overnight.

I believe the prop shaft was bent slightly from the first flight so I replaced the motor. The mount is now solid and the motor runs with minimum vibration.

The flight above was 8 minutes 45 seconds total and used 900 mah from the Lipos. One Lipo (1600mah) may be sufficient for most flights. It would give me about 10 km range with power left for two or three landing approaches. That lowers AUW and moves the CG back a bit.

Tom
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Last edited by Tom Harper; Dec 04, 2012 at 06:41 PM.
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Old Dec 04, 2012, 07:17 PM
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Palmdale, CA
Joined Oct 2000
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I flew the GoPro Hero 3 this afternoon.. set for 5 second time lapse photos... went well. I like the detail in the images.
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Old Dec 04, 2012, 08:31 PM
Lift is cheap - Drag sucks
Tom Harper's Avatar
Socorro, NM
Joined Jul 2004
3,664 Posts
Definitely wide angle!

Wing tip's a neat shot.

Tom
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Old Dec 04, 2012, 10:17 PM
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Palmdale, CA
Joined Oct 2000
13,499 Posts
Those ultra-wide lenses are only decent for level images... any looking up or down gives a very distorted image.
110 degree field of view is nice though.
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