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Old Jan 06, 2012, 10:14 PM
Long Range FPV'er
Joined Feb 2009
575 Posts
Does this explanation help anyone??

Quote:
Originally Posted by garris2 View Post
Make sure the following settings are made in the OSD.

d) Set the “Choose Receiver Type” to “PCM/FS” in the same menu
e) Set “Number Failsafe Chans on RX” to “1 FS Chns” in the same

Set up a mix on the throttle that mixes throttle into itself such that when you flick the switch it moves the throttle 10% more past idle.
ie,
RTH test off, -100%---0%---+100%
RTH test on, -110%---0%---+100%

Set all other throttle trims, travels and end points to their defaults.

Failsafe for the throttle should be set with the stick at idle, trim at neutral and your RTH test switch to the ON Position.

Repeat
set your Failsafes with the RTH switch in the ON position.

Failsafes for all your other channels should be set for Straight and level flight.

Before you run the Servo Analysis Wizard, set the RTH switch in the OFF position.

Now run the Servo Analysis Wizard, make sure throttle trim is at Neutral before you start.

At the point where you are asked to turn your RC Tx off, the receiver will detect the Failsafe positions (throttle travel lower with stick at idle as set by your Failsafe positions), and this will be recorded by the OSD.

Now when you are flying and you want to test RTH, move your throttle stick to idle and flick your RTH switch, the OSD will see this as the receiver going into Failsafe and activate RTH.

To turn off RTH flick your RTH switch back or move the throttle stick up.

* You can also choose Option C “3Pos (RTH)” in the Radio Control Setup Menu / Choose Menu Receiver Inputs.*

Geoff
I couldn't figure out how to setup a failsafe switch on my futaba 9cap until reading this reply...

Quote:
Originally Posted by mentony32 View Post
Mykro,

I was using a 9CAP until just recently. For the RTH switch position, try setting the Throttle-Throttle mix to 10% with an Offset of 50%. Then have a look at the servo monitor to make sure the throttle travels 10% below the usual minimum travel limit when the RTH switch is activated.

Tony
This setup works perfect.. took less than a minute to configure in my radio...

Hope this helps...

Michael
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Old Jan 06, 2012, 10:44 PM
Registered User
United States, CA, Redlands
Joined Dec 2009
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Hey Guys,

I was wondering if anyone had this problem.......While in flight, accessing the menu, do you lose video?

Darrick
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Old Jan 07, 2012, 12:24 AM
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GregSilver's Avatar
United States, FL, Plantation
Joined Nov 2005
655 Posts
you do NOT lose video OR control of the plane, like with other OSDs on the market.

DOSD overrides your flight controls when the menu turns on.

ETOSD allows full control of the aircraft. Video is never lost as you can see through the text. This is typical of all OSDs

that being said....it takes some time to get used to the way the menu operates. using a 3pos switch to change the menu item, select menu item AND change the input of that menu item ....simply put, has a learning curve. Once you understand how to do it, its actually pretty easy.
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Old Jan 07, 2012, 11:10 AM
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United States, UT
Joined Jan 2011
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Quote:
Originally Posted by fordarrick View Post
Hey Guys,

I was wondering if anyone had this problem.......While in flight, accessing the menu, do you lose video?

Darrick
something is wrong
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Old Jan 07, 2012, 11:20 AM
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United States, CA, Redlands
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I'm going out to fly, I'll show you video of what I'm talking about when I get back. Thanks.

Darrick
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Old Jan 07, 2012, 09:54 PM
ScratchCrasher
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Greece, Central Macedonia, Thessalonika
Joined Jun 2008
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OK, I need some advice here please!

I am running ET OSD without Guardian on a scratchbuilt skywalker. When I am above RTH altitude, the OSD applies down elevator as well as shutting motor down, in order to decend. The problem is that even if I use small elevator stick deflection when the servo analysis wizard asks to pull the elevator stick to climb position, the application of down elevator causes the airplane to nose dive very steeply. On top of that, crusing throttle kicks in as soon as crusing alt is reached, but the plane is already diving vertically down, and the throttle just worsens the situation . In one occasion when I had enough height and nerves to allow the OSD to keep doing its thing, the plane did an 180deg half loop downwards and ended inverted before I took back control.

I uploaded a short clip of the situation here, if anyone wants to have a look. Sorry for the bad quality - I still have a long way to go

Did anyone had similar experience? How do you suggest to overcome this problem (except from buying the guardian or another stabilization system at the moment) please? Would a possible solution be to not apply up elevator when prompted during the servo analysis wizard, and therefore rely on the throttle position for altitude control (off for descend, climb for ascend).

Note: This airplane is slightly positively stable (it pulls up the nose gradually during a 45deg dive).
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Old Jan 07, 2012, 11:05 PM
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United States, UT
Joined Jan 2011
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I really don't know if you can do it without stabilization, but

In the safety menu, Pitch proportional gain controls rate of climb.

even if you are using stabilization, and your plane dives, you want to increase the pitch proportional gain until the plane climbs like you want it.


Quote:
Originally Posted by sfakias View Post
OK, I need some advice here please!

I am running ET OSD without Guardian on a scratchbuilt skywalker. When I am above RTH altitude, the OSD applies down elevator as well as shutting motor down, in order to decend. The problem is that even if I use small elevator stick deflection when the servo analysis wizard asks to pull the elevator stick to climb position, the application of down elevator causes the airplane to nose dive very steeply. On top of that, crusing throttle kicks in as soon as crusing alt is reached, but the plane is already diving vertically down, and the throttle just worsens the situation . In one occasion when I had enough height and nerves to allow the OSD to keep doing its thing, the plane did an 180deg half loop downwards and ended inverted before I took back control.

I uploaded a short clip of the situation here, if anyone wants to have a look. Sorry for the bad quality - I still have a long way to go

Did anyone had similar experience? How do you suggest to overcome this problem (except from buying the guardian or another stabilization system at the moment) please? Would a possible solution be to not apply up elevator when prompted during the servo analysis wizard, and therefore rely on the throttle position for altitude control (off for descend, climb for ascend).

Note: This airplane is slightly positively stable (it pulls up the nose gradually during a 45deg dive).
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Old Jan 08, 2012, 12:40 AM
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United States, UT
Joined Jan 2011
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sfakias,

I watched your video, and I would like to see your settings.

could you post them please.

also- are you using rudder or ailerons for RTH?

-Mike
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Old Jan 08, 2012, 01:04 AM
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Oklahoma, USA
Joined Sep 2010
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Quote:
Originally Posted by sfakias View Post
OK, I need some advice here please!

I am running ET OSD without Guardian on a scratchbuilt skywalker. When I am above RTH altitude, the OSD applies down elevator as well as shutting motor down, in order to decend. The problem is that even if I use small elevator stick deflection when the servo analysis wizard asks to pull the elevator stick to climb position, the application of down elevator causes the airplane to nose dive very steeply. On top of that, crusing throttle kicks in as soon as crusing alt is reached, but the plane is already diving vertically down, and the throttle just worsens the situation . In one occasion when I had enough height and nerves to allow the OSD to keep doing its thing, the plane did an 180deg half loop downwards and ended inverted before I took back control.

I uploaded a short clip of the situation here, if anyone wants to have a look. Sorry for the bad quality - I still have a long way to go

Did anyone had similar experience? How do you suggest to overcome this problem (except from buying the guardian or another stabilization system at the moment) please? Would a possible solution be to not apply up elevator when prompted during the servo analysis wizard, and therefore rely on the throttle position for altitude control (off for descend, climb for ascend).

Note: This airplane is slightly positively stable (it pulls up the nose gradually during a 45deg dive).
In the video the plane is already stalling at 20 mph when the RTH kicked in and the Elevator went up to 32 and then to 64 like it should to hold atlitude. But the stall was already deep and continued to develop until the airspeed dropped to 15 when the plane started to pick up speed. RTH without the guardian can only fly a stable plane. It didn't know how to recover from the stall and loses it. Try the RTH from level stable flight and see what it does. Better yet, get a Guardian. You won't be sorry.

My Radian couldn't fly well in RTH mode until I added the Guardian. Today the Guardian flew it almost hands off 11000 feet out and then it and RTH returned the plane home hands off. I only lost 200ft of altitude on the way back with no throttle at all. It did get a 200ft updraft at one point on the way back. I had a 10 mph tail wind that also helped.

Steve
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Old Jan 08, 2012, 06:08 AM
ScratchCrasher
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Greece, Central Macedonia, Thessalonika
Joined Jun 2008
579 Posts
Quote:
Originally Posted by m_beeson View Post
sfakias,

I watched your video, and I would like to see your settings.

could you post them please.

also- are you using rudder or ailerons for RTH?

-Mike
M_beeson thank you for your reply.

My settings are the default PID controller parameters settings. I have not tweaked them yet.

I use the rudder, not the ailerons, but it is very responsive. I have also used slight up elevator with rudder for turning left input controls during the wizard.

RTH works on the plane, it is just not tailored to perfection yet. When RTH kicks in within the cruising altitude window, the plane gets safely back to home. It does porpoising and also zig-zags slightly, which I understand both can be fixed by optimizing the PID controller parameters, and the max control surfaces deflections. At the moment, it does not look pretty, but it works, and it also holds circling pattern above home.

I am aware that I need to spend more time testing in order to make it smooth. However, I was just wondering if the elevator deflection is necessary, even for a plane that descends with motor off, and you just need to advance the throttle in order to ascend. Because, in my case, a small down elevator input for just a few seconds can send the plane in a high speed nose dive - a situation impossible to auto-recover without guardian. During normal flight, I just use throttle off to descend. I mostly use down elevator during inverted flight
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Old Jan 08, 2012, 06:28 AM
ScratchCrasher
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Greece, Central Macedonia, Thessalonika
Joined Jun 2008
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Quote:
Originally Posted by Floater73 View Post
In the video the plane is already stalling at 20 mph when the RTH kicked in and the Elevator went up to 32 and then to 64 like it should to hold atlitude. But the stall was already deep and continued to develop until the airspeed dropped to 15 when the plane started to pick up speed. RTH without the guardian can only fly a stable plane. It didn't know how to recover from the stall and loses it. Try the RTH from level stable flight and see what it does. Better yet, get a Guardian. You won't be sorry.

My Radian couldn't fly well in RTH mode until I added the Guardian. Today the Guardian flew it almost hands off 11000 feet out and then it and RTH returned the plane home hands off. I only lost 200ft of altitude on the way back with no throttle at all. It did get a 200ft updraft at one point on the way back. I had a 10 mph tail wind that also helped.

Steve
Hello Steve, thank you for your reply.

This plane is mostly stable, however the RTH is not properly tweaked yet (see my reply to m_beeson above).

See this video of a successful RTH turn, again, sorry for the bad quality (on top of that I was flying into the sun to reach home).

About the elevator deflection in the first video that I posted, you can see that the elevator was at -96 (pushing nose down) for a few seconds, until the plane was well into the dive. This is what I want to avoid.

Anyway gents, thank you for your input, I will do more testing, when weather and life permits, and will keep you informed of the results.

Regards.
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Old Jan 08, 2012, 08:39 AM
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Austria / Vienna
Joined Feb 2007
1,312 Posts
Quote:
Originally Posted by sfakias View Post
Hello Steve, thank you for your reply.

This plane is mostly stable, however the RTH is not properly tweaked yet (see my reply to m_beeson above).

See this video of a successful RTH turn, again, sorry for the bad quality (on top of that I was flying into the sun to reach home).

About the elevator deflection in the first video that I posted, you can see that the elevator was at -96 (pushing nose down) for a few seconds, until the plane was well into the dive. This is what I want to avoid.

Anyway gents, thank you for your input, I will do more testing, when weather and life permits, and will keep you informed of the results.

Regards.
hi "sfakias",

i flew the skywalker a long time without the guardian an a really good working rth.
i set all parameters to 20 and the rudder deflections like in this post
http://www.rcgroups.com/forums/showp...7&postcount=42

cheers Thomas
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Old Jan 08, 2012, 09:11 AM
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Jhondra's Avatar
United States, ID, Nampa
Joined Nov 2008
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Quote:
Originally Posted by sfakias View Post
OK, I need some advice here please!

I am running ET OSD without Guardian on a scratchbuilt skywalker. When I am above RTH altitude, the OSD applies down elevator as well as shutting motor down, in order to decend. The problem is that even if I use small elevator stick deflection when the servo analysis wizard asks to pull the elevator stick to climb position, the application of down elevator causes the airplane to nose dive very steeply. On top of that, crusing throttle kicks in as soon as crusing alt is reached, but the plane is already diving vertically down, and the throttle just worsens the situation . In one occasion when I had enough height and nerves to allow the OSD to keep doing its thing, the plane did an 180deg half loop downwards and ended inverted before I took back control.

I uploaded a short clip of the situation here, if anyone wants to have a look. Sorry for the bad quality - I still have a long way to go

Did anyone had similar experience? How do you suggest to overcome this problem (except from buying the guardian or another stabilization system at the moment) please? Would a possible solution be to not apply up elevator when prompted during the servo analysis wizard, and therefore rely on the throttle position for altitude control (off for descend, climb for ascend).

Note: This airplane is slightly positively stable (it pulls up the nose gradually during a 45deg dive).
Hum...a couple things here.

1) "The plane is slightly positively stable"...I hope that just means your neutral on your elevator makes it pull up in a high speed dive...as you lose speed, the elevator won't make any difference, and your CoG will take over...that better make the nose drop and dive...eventually this will balance out in a slow descent without any control from you. Too many issues with RTH are from a plane that isn't inherantly stable to begin with...especially without guardian.

2) Your video shows you entering RTH already in a very nasty situation. It would be good to see how it behaves as follows (and this is the best way to progressively deal with RTH without trouble shooting everything at once):
a) Start with making sure your plane is actually stable before throwing RTH at it. Can you get it level...flying at around 25mph (shouldn't stall there), and with neutral elevator, does it want to climb very, very, very slightly? Take note of throttle needed to keep it 25-30mph and use that for your cruise in servo settings later. Ok, now, chop throttle completely off from level 25-30mph flight. Does it nose down too much? It should just gradually drop into about a -5' pitch and begin bleeding off speed down to something under 20mph. If this goes well and it is eventually hits a stable flight (don't worry too much about aileron stability right now...just keep it level while you watch elevator response), begin to see what stall speed is and what it does. Pull back on elevator very slightly until you slowly bleed off speed and begin seeing it want to stall (controls will get mushy and it will want to roll, and HOPEFULLY, it better want to keep dropping nose on you...if it doesn't, you are tail heavy). What MPH is this at? Make sure cruise is well above this. If you then release controls (keep making aileron corrections for level flight), does it eventually drop the nose, pick up speed and return to the slowly descending ~20mph glide? It better or you have airframe problems. While you are doing this, take note of what max aileron servo deflection you need to slowly roll into a 20' turn, and use that for the max turn servo wizard.

Too many people START with b), and don't have a well behaved plane, and it makes for very hard flying and impossible RTH setup.

b) OK...assuming you have good flight behavior on your plane, start straight and level heading back TOWARD your home position. At cruise speed and above minimum altitude. See what RTH does engaging now..this should be the SIMPLEST. If this doesn't work, you've got altitude and cruise speed setting problems and/or your plane is not stable with good CoG and/or your servos for straight and level flight have NOT been done correctly...i.e. go back to a).

c) If that works, move on to below min altitude headed toward you from a ways out and see if it throttles up ok and climbs. Do the same thing high up, and a couple other things to see if it works ok...and watch what it does as it crosses over into the "home" altitude area and overhead...be ready to take back control, as you need to work on turns next.

d) If that worked, move on to the next. Straight and level flight going AWAY, around 25mph, heading about 90' out at about 500-1000ft (for example, with plane due north of you at about 750' distance and 700' high heading due West or East). Engage RTH and see what happens. Record it. Turns are hard for RTH to do without guardian, as it can tend to turn..turn...turn...right into a roll, especially with high throws and gains, which typically results in the exact same death dive you just had...back off your max turn servo deflections and/or drop some of the "I" on your turn. Do NOT complicate things during the servo wizard and do elevator up...what you would do for a coordinated turn is the final result of all the PID settings...compensating for one of those as an input will make it tougher to debug. Make sure this works for heading both East and West. If that works well, then you can move on to heading 180' away from you. If it doesn't respond very well (SLOW TURNS ARE BEST...don't worry if it takes 90 seconds to get turned back toward you), increase the Integral setting a little. If it really over turns and never really settles in a nice flight back toward you (over turns, misses, comes back...over turns...oscillations, it is under damped), increase Derivative setting...or drop Integral (though dropping integral will make it even longer to begin the turn and can keep it from responding fast enough in an extremely bad situation to begin with).
Start with some of that, and watch video and post it back here. I think you'll find at least 4 things to change/start with. And I would recommend doing the first part even if you have guardian...

Best Regards,

Jeff
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Old Jan 08, 2012, 09:15 AM
KF7JBN
Jhondra's Avatar
United States, ID, Nampa
Joined Nov 2008
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Quote:
Originally Posted by sfakias View Post
Hello Steve, thank you for your reply.

This plane is mostly stable, however the RTH is not properly tweaked yet (see my reply to m_beeson above).

See this video of a successful RTH turn, again, sorry for the bad quality (on top of that I was flying into the sun to reach home).

About the elevator deflection in the first video that I posted, you can see that the elevator was at -96 (pushing nose down) for a few seconds, until the plane was well into the dive. This is what I want to avoid.

Anyway gents, thank you for your input, I will do more testing, when weather and life permits, and will keep you informed of the results.

Regards.
I can tell you right now, you have WAAAAY too much aileron control for max turns set in the wizard (probably elevator too, but that wasn't obvious here). At least for starting out. This should be very slow and careful on response. I started out wanting a very authoritative turn just like I run for 3D and stuff...grin. One of the biggest problems with RTH is it is only going to be able to respond nicely as fast as the GPS updates can feed back, and that isn't great. Gyros on guardian help a LOT and can do a lot better recovery for faster responses without sending the system into PID meltdown. I'm also surprised how fast you're trying to go. What do you have speeds set too? Try to only be ~10mph above stall, which should be around 25 (stall is probably under 15 for a good wing load skywalker or EZ*).

Hope this helps,

Jeff
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Old Jan 08, 2012, 09:55 AM
ScratchCrasher
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Greece, Central Macedonia, Thessalonika
Joined Jun 2008
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Quote:
Originally Posted by Thint1 View Post
hi "sfakias",

i flew the skywalker a long time without the guardian an a really good working rth.
i set all parameters to 20 and the rudder deflections like in this post
http://www.rcgroups.com/forums/showp...7&postcount=42

cheers Thomas
Thank you Thomas for pointing this post to me - the vid "does not exist" , but you describe a few tips that may help during setup.

Regards,
Stavros
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