HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Oct 12, 2012, 03:31 PM
Registered User
skubacb's Avatar
Tucson, AZ
Joined Aug 2006
353 Posts
On the off option. Be careful, if the surface has a balance tab it could free wheel full up or down. You may wonder how I know this. Did land but with some puckering. BTW this was a wire failure nothing to do with RXs.
skubacb is offline Find More Posts by skubacb
Reply With Quote
Sign up now
to remove ads between posts
Old Oct 12, 2012, 04:29 PM
Xtreme Power Systems
Lake Havasu, AZ
Joined Jun 2005
15,917 Posts
Yes, you definitely do NOT want to use the OFF feature of the failsafe for a surface that move! I have seen a few test cases myself that even without balance tabs surfaces move and get stuck in an overthrow condition (that would not normally happen when the servo is driven). Ugly, ugly, ugly when that happens!

The OFF feature was added after many people requested it so that they could monitor failsafe conditions and use auto-pilots that watch the PWM pulse from the receiver to enable the auto-pilot mode.
JimDrew is online now Find More Posts by JimDrew
RCG Plus Member
Reply With Quote
Old Dec 12, 2012, 06:34 AM
Registered User
Doffen24's Avatar
Norway
Joined Sep 2008
232 Posts
1/4 Scale Super Cub with 2 nano´s, success maiden flight

Quote:
Originally Posted by JimDrew View Post
I DON'T recommend splitting the surfaces UNLESS you are going to set the failsafe to a neutral position for each controlled surface. A good example of a potential problem is if two receivers were to control each elevator half. Even if one surface went neutral because of a failsafe, pulling or pushing the functioning elevator half would induce a roll. It all depends on your personal preference of what happens during a failsafe. The good news is that we really don't need to worry about signal loss.
Success with your own company Jim !!

My large 1/4 scale Super Cub flew like a dream with the two nanos. I have split surfaces, with failsafe to neutral as you recommended.
The preflight range test was very good, I guess about 50 meters +. But still i have some doubts regarding the Nano´s installation.

The Nano´s placed way back in cockpit, on each side of fuse.
Antenna´s in line with the direction of flight, but higher than electric motor, esc, etc with about 10-15 mm clearance (when flying level).
The places meet the requirements.

Questions:
1. I was looking around for a radiation pattern with distance measurement for the Nano´s. Have you made one?

2. Should I rather have antenna orient 45 or 90 degrease on flight direction, or is the range in the weakest part of radiation still sufficient (Pointing towards transmitter on loooong final approach).
Doffen24 is offline Find More Posts by Doffen24
Last edited by Doffen24; Dec 12, 2012 at 06:37 AM. Reason: ya, it was..
Reply With Quote
Old Dec 12, 2012, 12:20 PM
Xtreme Power Systems
Lake Havasu, AZ
Joined Jun 2005
15,917 Posts
Nice plane!

I never made a radiation pattern, but it is a standard dipole with a tuned circuit, so I expect the 'doughnut' to be off a little bit to one side.

Keep in mind that the two wires form a single antenna. So, with the wire stretched out, the parallel lines running from both sides of the receiver are the narrowest point of that doughnut. So, with your setup the absolute worst case (and how you should be range checking) is with the nose (or the tail) of the aircraft pointed directly at you. If your range testing is good that way, then you won't have any issues as the signal reception only improves the closer you get to perpendicular to antenna axis (the side of your plane in your case).

MAKE SURE that those wires for the flaps and ailerons are NOT moving anywhere near the antenna!!!! I can't stress this enough. If those wires passed over the antenna, the antenna tuning changes completely and you can lose all signal! Use some type of wire holding device (rubber bands work great for cases like this) that prevents the wires from just dangling and moving around.
JimDrew is online now Find More Posts by JimDrew
RCG Plus Member
Reply With Quote
Old Dec 12, 2012, 09:28 PM
Build more, websurf less
FlyingW's Avatar
Long Valley, NJ, USA
Joined Dec 2001
1,713 Posts
Jim,

I've been flying my Four Star 120 on two Nano receivers as situated as in the first figure (airplane top view). The aft rx with the antenna parallel to the flight path has the rudder, elevator, and throttle servos, the forward one with the antenna parallel to the wingspan has the ailerons and flaps. No problems, but your advice on the orientation is interesting and if I can improve things I'm open to ideas.

Would rotating both receivers as seen in the second diagram improve the reception for a wider set of typical orientations? I'm thinking that the aft one (that used to be parallel to the flight path) might have improved reception when flying head on, like on landing approaches.

What do you think? I am having trouble picturing that dipole doughnut thing relative to the shape of the Nano Rx and its antenna wires.

Thanks,

Paul
FlyingW is offline Find More Posts by FlyingW
Last edited by FlyingW; Dec 12, 2012 at 09:35 PM.
Reply With Quote
Old Dec 12, 2012, 10:22 PM
↓↘→ + (punch)
theKM's Avatar
central PA.
Joined Sep 2004
20,213 Posts
orientation to each other is not important as they're not working together for diversity. I don't think their orientation is anywhere near as important as what you can do to get them separated from other equipment and flopping wires. I've just been using velcro to stick them to the sides of the turtledeck on my aerobatic planes...
theKM is offline Find More Posts by theKM
Reply With Quote
Old Dec 13, 2012, 07:51 AM
Build more, websurf less
FlyingW's Avatar
Long Valley, NJ, USA
Joined Dec 2001
1,713 Posts
Is this correct? Nano in red on an image taken from google. The figure eight shape is a cross-section of the "doughnut."

KM - Thanks for the clarification about the two Rxs not working together to achieve diversity. I am mostly concerned with the orientation of each Rx with respect to the transmitter in my hands on the ground - and I'll check my wiring for movement in the area of the Rxs.

Come to think of it, in what direction is the strongest signal coming off of the transmitter antenna?

Thanks,

Paul
FlyingW is offline Find More Posts by FlyingW
Last edited by FlyingW; Dec 13, 2012 at 08:00 AM.
Reply With Quote
Old Dec 13, 2012, 11:33 AM
Registered User
The Villages, Florida
Joined May 2003
499 Posts
Quote:
Originally Posted by FlyingW View Post

Come to think of it, in what direction is the strongest signal coming off of the transmitter antenna?

Thanks,

Paul
From the sides at the tip... that's why you should not point the antenna directly at the model....
JuanRodriguez is online now Find More Posts by JuanRodriguez
Reply With Quote
Old Dec 13, 2012, 02:35 PM
Registered User
Doffen24's Avatar
Norway
Joined Sep 2008
232 Posts
Quote:
Originally Posted by JimDrew View Post
Nice plane!

I never made a radiation pattern, but it is a standard dipole with a tuned circuit, so I expect the 'doughnut' to be off a little bit to one side.

Keep in mind that the two wires form a single antenna. So, with the wire stretched out, the parallel lines running from both sides of the receiver are the narrowest point of that doughnut. So, with your setup the absolute worst case (and how you should be range checking) is with the nose (or the tail) of the aircraft pointed directly at you. If your range testing is good that way, then you won't have any issues as the signal reception only improves the closer you get to perpendicular to antenna axis (the side of your plane in your case).

MAKE SURE that those wires for the flaps and ailerons are NOT moving anywhere near the antenna!!!! I can't stress this enough. If those wires passed over the antenna, the antenna tuning changes completely and you can lose all signal! Use some type of wire holding device (rubber bands work great for cases like this) that prevents the wires from just dangling and moving around.
Thanks for the reply and suggestions Jim.
Suspected it was a dipole. Had that in mind the whole time, but the rangetest was going to deside if I would fly it or not.
And yes, tale in/out was what I focused on during range test, with good result.

Actually not easy to find The perfect place for two nanos. The 2" rule includes the distance between Nano antennas as well I guess.
Perpendicular to direction was my first choise, but impossible to do without even more servowires.
Anyway, not going to take any more chanses, will change the antennas direction.
The flaps and ailron -wires where secured with nylon ties, but I will add some rubber band inside wings to keep them stretched.
Doffen24 is offline Find More Posts by Doffen24
Reply With Quote
Old Dec 13, 2012, 02:45 PM
Registered User
Doffen24's Avatar
Norway
Joined Sep 2008
232 Posts
Quote:
Originally Posted by FlyingW View Post

Come to think of it, in what direction is the strongest signal coming off of the transmitter antenna?

Thanks,

Paul
The same as the Nano antenna.
Do not point TX antenna towards the airplane...
Doffen24 is offline Find More Posts by Doffen24
Reply With Quote
Old Dec 13, 2012, 03:53 PM
Xtreme Power Systems
Lake Havasu, AZ
Joined Jun 2005
15,917 Posts
Yep, you guys are all correct on your theories. Nanos do not work together to provide any type of diversity. However, I have thought about making the bigger power expander (XPander+) with the ability to use two Nanos for diversity. You would have to program them as Master/Slave, and only the master could be programmed for channel mapping, offsets, and reversing. But this would be a way to get true diversity. We had the satellite receivers for that - as a big request by Graupner. They soon learned that it didn't make a bit of difference in the real world. Both receivers would have signal loss at nearly the same time. So, I am not sure how much sense it makes to provide diversity support other than making someone feel warm and fuzzy because they spent more money for an extra receiver that they really didn't need.
JimDrew is online now Find More Posts by JimDrew
RCG Plus Member
Reply With Quote
Old Dec 14, 2012, 08:03 AM
Build more, websurf less
FlyingW's Avatar
Long Valley, NJ, USA
Joined Dec 2001
1,713 Posts
Thanks for all your explanations.

I suppose if the radiation patterns of both the Tx and Rx were both spheres, then any orientation would be optimal.

Given the doughnuts and lobes and such of the real-world emissions of these devices, and the evidence from flying that the signal strength is strong enough in any orientation my planes have experienced, I am happy with the product as is.

I want to go flying.
FlyingW is offline Find More Posts by FlyingW
Reply With Quote
Old Dec 18, 2012, 04:09 AM
Registered User
Doffen24's Avatar
Norway
Joined Sep 2008
232 Posts
Quote:
Originally Posted by theKM View Post
orientation to each other is not important as they're not working together for diversity. I don't think their orientation is anywhere near as important as what you can do to get them separated from other equipment and flopping wires. I've just been using velcro to stick them to the sides of the turtledeck on my aerobatic planes...
Hi. I am curios.
I see you have a vertical orientation of antennas in your installation. How is the range in the formal range test compared to Horizontal orientation ? Thinking doughnut radiation pattern. Obviously, you should get the weakest signal flying level high straight above you.
But than again, you might just only hover, which makes antennas horizontal



Quote:
Originally Posted by JimDrew View Post
Nice plane!

I never made a radiation pattern, but it is a standard dipole with a tuned circuit, so I expect the 'doughnut' to be off a little bit to one side.

So, with your setup the absolute worst case (and how you should be range checking) is with the nose (or the tail) of the aircraft pointed directly at you.
I just changed mine two nanos in the 1/4 scale Super Cub - to a V shape, horizontal orientation, just a bit over 2" apart tip-tip. Now have to wait on nice weather to range test it.
Any experience with V shape config.?
To which side will the Radiation be off?
Doffen24 is offline Find More Posts by Doffen24
Last edited by Doffen24; Dec 18, 2012 at 04:14 AM.
Reply With Quote
Old Dec 18, 2012, 11:05 AM
Xtreme Power Systems
Lake Havasu, AZ
Joined Jun 2005
15,917 Posts
If you are going to do a V shaped, I would recommend tipping the V inwards towards the front of the plane. Otherwise, on final you could end up standing the same angle as the outward pointing V.

In reality, it probably makes very little difference as the range is about 1/2 if both antennas are pointing perfectly at each other. So, half of mile or so (at ground level) is probably further out than most fly anyways.
JimDrew is online now Find More Posts by JimDrew
RCG Plus Member
Reply With Quote
Old Dec 18, 2012, 05:07 PM
Registered User
Doffen24's Avatar
Norway
Joined Sep 2008
232 Posts
Quote:
Originally Posted by JimDrew View Post
If you are going to do a V shaped, I would recommend tipping the V inwards towards the front of the plane. Otherwise, on final you could end up standing the same angle as the outward pointing V.

In reality, it probably makes very little difference as the range is about 1/2 if both antennas are pointing perfectly at each other. So, half of mile or so (at ground level) is probably further out than most fly anyways.
Thanks for replying. Jim.
At some point one of The Antennas will point at The RC pilot.

Ok, so V shape is not a good choise.
With one receiver, antennas should point perpendicular to direction

What would you recommend with 2 Nanos in the same plane, and can't have both perpendicular to flight direction?
A slight V shape, L shape , H shape , vertical and Horizontal differential....TheKM style ...

I want The very best solution possible in this plane.
Doffen24 is offline Find More Posts by Doffen24
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Question Two Nanos for a Big Plane - Two Rx Batteries? FlyingW Xtreme Power Systems 16 Oct 19, 2012 01:24 PM
Discussion how close can you install two nanos to each other? rcfan450 Xtreme Power Systems 3 Sep 26, 2012 11:31 AM
Found XPS XtremeLink® 2.4GHz 6 channel Nano E or Nano RX's two hope jcstalls Aircraft - General - Radio Equipment (FS/W) 1 Jun 30, 2012 05:58 PM
Sold Two NIP Pentium 60 ESC for EDF applications and two NIP Pentium 80 amp ESC The Don Aircraft - Electric - Jets (FS/W) 5 Jul 22, 2009 11:51 PM
Discussion mapping channel 2 to channel 8for elevators 3ddd Xtreme Power Systems 5 Sep 23, 2007 04:22 PM