FPV HUB

Planes => Autopilots => Feiyu Tech => Topic started by: markvanhaze on May 09, 2012, 04:00:50 PM

Title: RTH question
Post by: markvanhaze on May 09, 2012, 04:00:50 PM
I have yet to get my RTH but I am wondering how it is initialized. When I fly at the limit of my range (35MHz) I usually notice it because the plane starts to move erratically. I guess its because the servos start to jitter. Normally I return immediately when I see that happen but if I had an RTH, would I simply fly on and would it then kick in automatically? How does it know when to do that? Is there a signal threshold or maximum amount of jitter that triggers it?
I know you can trigger it yourself too, but if I fly just out of range, im not sure flipping the RTH switch will come through the weak, jittery signal. And if it does, will that happen fast enough before the plane hits the ground?
Title: Re: RTH question
Post by: wgt40w on May 09, 2012, 04:12:23 PM
I'm no expert, but:-

1) The Failsafe operates the RTF - i.e. when your plane's receiver loses all radio connectivity from the tx, the RTF kicks in.

2) With some, but maybe not all, systems you can also set a tx switch (channel) to activate the RTF, whilst still in tx range.
Title: Re: RTH question
Post by: g.collins on May 09, 2012, 07:12:23 PM
wgt40w is correct, I have the FY21 and AP117 and that works that way.
;) G
Title: Re: RTH question
Post by: markvanhaze on May 09, 2012, 07:24:12 PM
So until the failsafe kicks in, you are flying a really nervous, glitchy plane?
Title: Re: RTH question
Post by: wgt40w on May 09, 2012, 07:38:28 PM
Quote from: markvanhaze on May 09, 2012, 07:24:12 PM
So until the failsafe kicks in, you are flying a really nervous, glitchy plane?

Sounds like you are now referring to 'stabilisation' rather than RTH.

RTH is where the plane flies back to the 'start' point - usually where the pilot is. On arrival it circles around.

Stabilization is a separate, manually switched on or sometimes permanently on, system that 'corrects' sudden changes in the plane's orientation (due to wind gusts etc.)

Stabilization of the type that can be manually switched on should NOT be on when RTH is also switched on.
Title: Re: RTH question
Post by: markvanhaze on May 09, 2012, 07:48:21 PM
That makes sense now. I assume correctly then that the stabilizer manages to keep the plane steady even when the servos start glitching?
Title: Re: RTH question
Post by: g.collins on May 09, 2012, 08:07:17 PM
No mate, the stabilization works to counter the effects of turbulence when flying, not if your servos twitch because you are growing out of range, the RTL will tern on when the plan goes out of range, my system changes the OSD screen when the RC receiver starts to loos the signal and starts flicking in to RTL.
;) G
Title: Re: RTH question
Post by: markvanhaze on May 09, 2012, 09:54:59 PM
Thanks for the help offer but I don't have a real problem with glitches. I do fly at the limit of my range sometimes and that's around 2.5 km on a corona with a 202cm antenna. That's when I get glitches which I suspect is to be expected at that distance.
All I wanted to know was how you handle the time period between being on the fringe of reception and the rth kicking in. My failsafe does not kick in on the first sign of a glitch, or so I believe because that's hard to say based solely on my video feed, which leaves a time window between first glitch and the rth.
Title: Re: RTH question
Post by: 6lennn on May 09, 2012, 10:05:57 PM
i believe the fy21ap relies on the rx telling it to go into rth mode
either through a switch and spare channel or having your failsafe set to rth with a bit of throttle

you could test either by switching your tx off when your getting a lot of glitches or more safely by retracting your tx antenna and pointing it at the plane (simulating a loss of signal)


Title: Re: RTH question
Post by: Coyote on May 09, 2012, 10:15:04 PM
Yes that`s how its activated as Glenn says. You need throttle of around 50% but be carefull you don`t activate it ( tx off ) when your fingers are near prop 
Title: Re: RTH question
Post by: 6lennn on May 09, 2012, 10:32:30 PM
all hell breaks loose when that happens, ask me how I know
btw plastic props can make quite a mark on ceramic tiles, who would have thought!
Title: Re: RTH question
Post by: AndyP on May 09, 2012, 10:58:49 PM
So really its a good idea to have RTH from the very beginning of your fpv career? Seems like a win win situation for me.
Title: Re: RTH question
Post by: Coyote on May 09, 2012, 11:15:05 PM
Not really no, its best to start off simple, that way there is less to go wrong and fault finding is easier. The more complicated the more that can go wrong and the more incompatibilities can arise
Title: Re: RTH question
Post by: 6lennn on May 09, 2012, 11:26:34 PM
@AndyP

Quote from: 6lennn on May 09, 2012, 09:43:26 PM
rth shouldnt really be thought of as a get out of jail card
Title: Re: RTH question
Post by: AndyP on May 09, 2012, 11:40:14 PM
I didn't notice what you said in your earlier post 6lennn but it makes total sense thinking about it. That and going simple to start with.
Title: Re: RTH question
Post by: 6lennn on May 09, 2012, 11:52:44 PM
trouble is we all want, rth, osd's, fancy video, long long range, etc
money can buy anything except experience

I have spent over 2k to get a £200 plane flying in the air properly, but nothing anyone said at the begining would have made me do anything different, i thought i knew better, im a pratt like that
Title: Re: RTH question
Post by: Asomaro on May 10, 2012, 12:25:16 AM
Quote from: 6lennn on May 09, 2012, 11:52:44 PM
trouble is we all want, rth, osd's, fancy video, long long range, etc
money can buy anything except experience

I have spent over 2k to get a £200 plane flying in the air properly, but nothing anyone said at the begining would have made me do anything different, i thought i knew better, im a pratt like that

I'm afraid the same comments apply to me ....
Title: Re: RTH question
Post by: g.collins on May 10, 2012, 12:39:16 AM
I have been flying little simple FPV planes for quite a while now, which has allowed me to get a lot of experience flying with the goggles on, at a low cost to my pocket, I had the fancy tek on stand by, but only started dabbling with RTL in the last 2 months or so, but I have a year of FPV experience now and still finding out every day that I have a lot to learn.  :laugh:
;) G