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Old Aug 12, 2010, 01:31 AM
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United States, CA, San Jose
Joined Jul 2009
1,370 Posts
Question
How different is a quadcopter vs a plane via FPV?

I've been flying my EasyStar and from the beginning it's been excpeptionally easy to fly via FPV. I wanted something for lower altitude flying and hovering about, so I've just finished building my KapteinKuk based quadcopter and it flies stable and reliably. For now I've temporarly installed one of the $25 Sony 420TVL cams and a 200mW 900Mhz VTx, until some better components arrive. To be on the safe side, I'll be recording and reviewing several flights so I can get a feel for how onboard video looks before jumping into the pilot's seat. To tilt the odds in my favor a bit more, I've also added a stabilizer that quickly returns the copter to a hands off hover when I release controls.

My question goes out to all those who have some FPV quad/tri copter or heli experience under their belt. Once I do start flying FPV, I plan to fly in calm wind and well away from anyone to insure maximum safety. Except for trees, what should I watch out for and do you have any tips? To drop altitude, do you follow a downward glide path or just hover down? Reversing direction makes the quad copter and camera pitch upward, effectively loosing horizon and sense of position, so do you generally always fly forward (unless of couse when hovering about at slow speed)? If you lose video (assuming the copter will auto-hover) would you recommend slightly increasing the throttle to gain altitude and raise the antenna, lowering it a bit in hopes of a hard landing, or yawing around in a circle to change antenna position? Is it easy enough to land via FPV or better to take off the googles, spot the copter and set it down via 3rd person?
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Old Aug 12, 2010, 02:25 AM
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Daemon's Avatar
Lakewood, Colorado
Joined Aug 2002
28,667 Posts
May be overthinking it a bit as I suspect your quad is overstable, if anything,
but here's some tips.
You will need to learn to fly the left stick instinctively.
Don't descend vertically or you'll end up in your own rotor wash, which is unstable
at best, and fatal at worst.
Be careful stopping quickly (relative to the ground) after a downwind run, as your wash
with follow you. See the wiki article on "Settling with power" to understand the effect.

To slow down from going fast, I usually make a turn (left cyclic and left rudder) sliding
around sideways and ultimately ending up pointed back the way I came, rather
than just pulling back on the cyclic.

To get down from high altitude fast, just nose it over a bit and dive
without increasing power. Can spiral down if space is limited. What I said
about turning to stop applies doubly here.

I would never attempt to transition to/from goggles with a tri or quad.
Hard enough determining their orientation when you've got your eye on
it all the time, let alone half blind after you take the goggles off.
I've flown under the goggles 100% from the first FPV flight.

Don't try to hover really close to the ground right away. Tris and quads are not stable
in "ground effect". Better off staying a bit higher.

BTW, the biggest difference for me, being primarily a sailplane pilot who is not
afraid to fly my main battery down to the ESC cutoff and glide home (whether it's
the EZ* or a Funjet), is that with a tri or quad you've got a fixed limit on
flight time, and if you let the battery get low, your aircraft will fall from
the sky like a wounded duck at best, and a brick at worst.

ian
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Last edited by Daemon; Aug 12, 2010 at 02:37 AM.
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Old Aug 12, 2010, 03:32 AM
Registered User
United States, CA, San Jose
Joined Jul 2009
1,370 Posts
Thanks that was most helpful and probably already saved me a few crashes. Now if I can remember all that when I get up there.

With the stabilizer it actually descends vertical pretty stable but will start veering off if throttle is too low. With a FY-20A I've been able to cut the throttle completely (just for a couple seconds) and all I have to do is hit full power and let go of the sticks to auto-recover. I don't plan on testing it in a long freefall, but would be nice if it could save the copter in that circumstance.

I'll be mounting a 600TVL cam underneath on a hobbyking large tilt pod with T-Rex 600 80mm skids to protect it. I'm considering linking the tilt servo to my headtracker so I can quickly look down to gauge distance, but I'm not sure if that'll just disorient me, and if controlling it via proportional knob is a better way to go. The lipo alarm leds will be within view of the camera and the buzzer output connected to the audio line (with a resistor) to hear it down link.
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Old Aug 12, 2010, 05:41 AM
Praying for better weather
Coyote64's Avatar
Joined Dec 2007
4,174 Posts
Ive not built my Tri yet, but my mate KF52t was maidening his on sunday and he siad its just like flying a Coaxial heli flight characteristic wise very stable
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Old Aug 12, 2010, 08:15 AM
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mdw21's Avatar
Sarnia Ont. Canada
Joined Jul 2005
325 Posts
Quote:
Originally Posted by Daemon View Post
May be overthinking it a bit as I suspect your quad is overstable, if anything,
but here's some tips.
You will need to learn to fly the left stick instinctively.
Don't descend vertically or you'll end up in your own rotor wash, which is unstable
at best, and fatal at worst.
Be careful stopping quickly (relative to the ground) after a downwind run, as your wash
with follow you. See the wiki article on "Settling with power" to understand the effect.

To slow down from going fast, I usually make a turn (left cyclic and left rudder) sliding
around sideways and ultimately ending up pointed back the way I came, rather
than just pulling back on the cyclic.

To get down from high altitude fast, just nose it over a bit and dive
without increasing power. Can spiral down if space is limited. What I said
about turning to stop applies doubly here.

I would never attempt to transition to/from goggles with a tri or quad.
Hard enough determining their orientation when you've got your eye on
it all the time, let alone half blind after you take the goggles off.
I've flown under the goggles 100% from the first FPV flight.

Don't try to hover really close to the ground right away. Tris and quads are not stable
in "ground effect". Better off staying a bit higher.

BTW, the biggest difference for me, being primarily a sailplane pilot who is not
afraid to fly my main battery down to the ESC cutoff and glide home (whether it's
the EZ* or a Funjet), is that with a tri or quad you've got a fixed limit on
flight time, and if you let the battery get low, your aircraft will fall from
the sky like a wounded duck at best, and a brick at worst.

ian
Thanks Ian you may just have saved me from at least several ups and the repairs that follow

Cheers

MDW216
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Old Aug 15, 2010, 10:49 PM
"Let's put a camera on that.."
spagoziak's Avatar
Twin Cities, MN
Joined Feb 2010
1,063 Posts
Agreed, Ian, thanks for your perspective, I'm sure you just saved me lots of headaches too lol
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Old Aug 15, 2010, 11:20 PM
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mkmkmk13's Avatar
United States, CA, Orange
Joined May 2007
1,605 Posts
i have a Gaui 330X-S quad with an FY-20A that is on all the time
the first time i flew it fpv, i took off with goggles right above my eyes and got it to a hover which by the help of the FY-20A it hovers level hands off, wind might make it drift but never crash
once it was high enough i nudged the goggles and they fell right on, the first flight i kept it moving forward so i don't have to deal with going backward or loosing altitude
again made it hover high enough took off the goggles and brought it back down
the second time i went to a bigger place, so altitude was my friend
i started this flight with goggles on, i just hit the throttle and up it went
kept it moving forward while gaining altitude, once high enough i centered the sticks and it came to a complete stop.
it was different experience, i yawed around and as soon i see something interesting to look at, i would go there stop and enjoy
when your done you can also enjoy a nice low dive

Moe
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Old Aug 16, 2010, 07:26 PM
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United States, CA, Orange
Joined May 2007
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posted this in the multi rotor section also
(if this is cross posting let me know and i'll delete it)

here is a video demonstrating how i fly my first quad (complete noob)
the only heli experience i have is with a blade 400 that i can hover and do figure 8s with only
Gaui 330xs with FY-20A (2 min 23 sec)

if i fly it fpv without stabilization, i spend most of the flight making sure its level
i disconnected the wire from the rx that controls the fy-20a so its always on
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Old Aug 16, 2010, 10:33 PM
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Lakewood, Colorado
Joined Aug 2002
28,667 Posts
Flying with auto-pilot stabilization is cheating.

For one thing with a regular heli or multi-rotor without an auto-pilot, if you tip the cyclic
in some direction then it will start moving in that direction. If you center the stick, it
will continue moving in that original direction at the same speed for a while (it might slowly tip
back to level like a co-axial). With AP, when you center the stick it returns itself to level immediately,
and drifts to a stop relative to the wind. It's basically flying a different type of aircraft.

ian
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Last edited by Daemon; Aug 16, 2010 at 10:42 PM.
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Old Aug 16, 2010, 10:46 PM
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United States, CA, Orange
Joined May 2007
1,605 Posts
i flew it without the auto pilot,i do a good job
but i got this quad strictly for fpv and it just makes for a more comfortable flight
i'm also flying on 2.4 so it makes a perfect safety net
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