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Old Dec 16, 2010, 11:41 PM
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Tri copter

Some FPV flight around the local area. This place is a residential development that got started about 2 years ago, and no houses have been built. Wonder if they ever will?

It's a perfect FPV playground for multirotors. Lots of obstacles to make it really interesting, all within the 300m range of my Spektrum system. Who says Spektrum is unworkable for FPV? The video is just from a keychain cam, not the FPV cam, hence a bit of jello.

http://youtu.be/HhYPgtONAuU





Here's my version of a balanced, direct drive yaw control setup.

The rear pivot is an M3 bolt and blind nut turned around, the front pivot is the servo itself.
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Old Jan 08, 2011, 05:40 PM
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I don't use a separate bec just for startup, I connect power permanently from the balance lead to power the rx, gyros and servo. All ESC BECs are disconnected.

All up weight of the finished first version tricoper was 970g or 34.2oz RTF with 3s 2200mah Battery.

All FPV gear incl ET OSD + GPS + alt - 1162g
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Old Jan 19, 2011, 02:44 PM
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Switchable slaving of the pan servo to yaw stick:
http://www.rcgroups.com/forums/showthread.php?t=1362265
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Old Feb 11, 2011, 05:44 AM
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Sydney, Australia
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My Tricopter setup on Futaba 9C

SPECS:
Motors: RC timer 750kv
ESCs: Turnigy Plush 25A
Props: HK 11 x 4.7 SF
15" arms centre to prop hub
AUW 970g with FPV gear and 2200mah lipo

All main gyro gains are ganged and plugged in to throttle channel. Yaw gyro gain to channel 5.

Set for 120 degree swash
Parameter > Type > Heli (SR-3)

Swash AFR
AIL + 36%
ELE + 50%
PIT + 90%

Throttle curve (for motor gyro gain - remember the higher the number, the less gain)
Point 1 23.0%
Point 2 23.0%
Point 3 24.0%
Point 4 22.0% -> still tweaking points 4 and 5 (high throttle)
Point 5 20.0%

GYRO SENS
MODE >GY
Switch E
UP CNTR and DOWN all at AVC 20% (remember the higher the number, the higher the gain up to 100%)

High Rates / expo (for fooling around)
Alie 85 / -30
Ele 85 / -30
Rudd 125/ -30

Low rates / expo (for FPV flight)
Aile 65 / -30
Ele 65 / -30
Rudd 75 / -30

Remember to turn Revo mix INH, or the yaw gyro will come out of HH mode when the throttle is advanced.
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Old May 11, 2011, 11:02 PM
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My Tri has now been made into version II with Wii control (WM+ and NK) mounted onto the Paris 3.0 board. I also took the opportunity to add Eagle Tree current meter, OSD Pro, GPS sensor and altitide sensor. Has added to the weight which you can feel in flight. The tri has less power in punch out than before. Still a very nice FPV flyer. at 1.162 kg

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Old Jul 21, 2011, 12:18 AM
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Tips for Tricopter FPV flying

My experience has been quite different I find my tricopter MUCH easier via FPV than fixed wing fpv.

I think there are a couple of tricks that helped me:

I have my camera pointed exactly horizontal. That way when I want to hover, I just put the horizon in the middle of the screen and the machine stops and hovers. To move forward, put the horizon in the top third. Backwards, the bottom third. Just like in full scale flying, the position and orientation of the horizon is your primary reference for aircraft performance.

Taking off is sometimes a challenge. I start by giving power until the image starts to move and give is slightly more stick and HOLD it. I give it about a "stick thickness" more after the tri looks like it is about to lift off. With regular heli flying, you'll find you ease off the collective as soon as you break ground. If you try this via FPV I often over corrected, hitting the ground again, often sideways or backwards. Punch the power and hold it until you're at a safe altitude.

More altitude is best. Keep it moving fast up high will give you a better chance. Try not to look at the scenery. you'll be distracted at even 100'

To descend, just point the nose at the ground. If you were flying from ground veiw, you would just bring the collective down and modulate it to descend. with a fixed pitch multirotor via fpv it is very hard to see the descent rate. If you just nose it over and head for the middle of your park it will just fly down there. Don't be afraid of hammering the forward cyclic!

Keep it moving forwards. You have to hold forward cyclic the entire flight, but that's just how it is. For me this was a challenge coming from fixed wing. Even in a turn, don't pull back on the cyclic, keep it forward (just a touch) and adjust with power. When you're moving forwards you will stop worrying about backing into what you can't see. Much better for the confidence. I still find hovering in one spot low down the biggest challenge. The problem is that often the horizon goes close to the bottom of the screen making it difficult to judge position.

A WDR camera helps. I found if the sun was low, the shadows were all black and I couldn't tell where the ground features were.

On yaw trim, I use a Wii based board (pairs) and almost always have to make an adjustment to the yaw trim on the first flight of the day (sometimes as many as 10 clicks), and then usually back again for the second flight. Then it stays trimmed. I think it has something to do with the gyros warming up, but whatever, it's no problem to trim the yaw in flight.

Above all it's just practice. I have 18 hrs now on my tricopter, and now have a bunch of experience flying in and around trees etc. So much fun...

sub...
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Old Mar 24, 2014, 10:33 PM
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Australia, NSW, Brookvale
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Great write up Sub.

Quote:
Originally Posted by subsonic View Post
I have my camera pointed exactly horizontal. That way when I want to hover, I just put the horizon in the middle of the screen and the machine stops and hovers.
I made a camera mount with polymorph plastic that left the camera pointed down a bit. I used the camera's osd feature to put a dash on the screen exactly where the nose points. Works great and makes hovering/landing a bit easier since I can see more of the ground. Although I can't tilt as far forward before the horizon goes off the top.

Quote:
Originally Posted by subsonic View Post
To descend, just point the nose at the ground.
I'm going to try that.
A real heli pilot friend said never descend in your own prop wash. So keep it moving forward as you descend so that the props always have clean air under them.
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Old Mar 24, 2014, 11:01 PM
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Quote:
Originally Posted by rogueqd View Post
Great write up Sub.

I made a camera mount with polymorph plastic that left the camera pointed down a bit. I used the camera's osd feature to put a dash on the screen exactly where the nose points. Works great and makes hovering/landing a bit easier since I can see more of the ground. Although I can't tilt as far forward before the horizon goes off the top.

I'm going to try that.
A real heli pilot friend said never descend in your own prop wash. So keep it moving forward as you descend so that the props always have clean air under them.
Yep, exactly on the camera angle. If you fly slowly, you can get away with the camera pointing down during a hover. Move too fast though and as you describe, the horizon goes off the top of the screen and you can lose orientation easily. I found that having the camera perfectly level suited my flying style.

Your heli pilot mate is probably correct re descending. My experience in flying FPV multirotors are not all that recent though. The above was written when we were all flying gyro based stabilisers and self-hacked multiwii boards were state of the art. I'm sure the more modern systems are capable of descending vertically without losing control like my old boards would. I had an old video up on youtube, but since took it down where I was flying well over 1000' and to descend, just pitched down to put the middle of the oval in the centre of the screen, and waited for it to get big. Tons of fun!

More modern boards are able to descend inverted while still maintaining control in all axis. My old stuff would certainly crash with that type of treatment.

Sub.
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