Go Back  RCU Forums > RC Airplanes > RC Jets
Reload this Page >

Advise please on onboard radio choice

Notices
RC Jets Discuss RC jets in this forum plus rc turbines and ducted fan power systems

Advise please on onboard radio choice

Old 03-03-2015, 03:58 PM
  #1  
R Pursall
Junior Member
Thread Starter
 
Join Date: Jun 2008
Location: St.Columb Major, UNITED KINGDOM
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Default Advise please on onboard radio choice

Hi guys, I'm about to embark on my next jet project, and am struggling to decide on how to do the installation (by that I mean which servos, powerbox or no powerbox, sbus or not etc.
My first jet was a viper2m which I unfortunately lost due to a flap sticking etc. In that I had a powerbox royal, sensor switch with two lipos and two 14ch receiver's, Jr 8411 servos and I had a futaba 14mz.
Firstly the new jet, I want a stress free easy to fly jet that also looks good (don't we all! ) anyway I've narrowed it down to either the arg dynamo or the redwings gryphon evo... Still can't decide which one, I think the dynamo flies very well and light, where as the gryphon evo looks more "jet like".. Almost down to flipping a coin.!
Anyway back to the installation question... I now own a futaba 18mz and have a R7008SB receiver that came with it.
But, I do want to fit an igyro 3e so that rules out going down the sbus route!. I'm a bit skeptical of an sbus setup, with all servos going to one connection on the receiver,.. If that one connection should pop out then I loose all servos... Any comments appreciated.
Anyway what I do want is,.. An igyro 3e, something like a powerbox sensor switch that will give the redundancy of two lipo batteries. (but if I use the R7008SB receiver (or two) then I wouldn't need a regulator in the switch as the receiver copes with high voltage? On the subject of receiver's, I can link two R7008SB receiver's to the 18mz (not tried it yet) so was wondering if I put left aileron, left elevator, left rudder on one receiver, and right ail, ele, rud on the other receiver?... Wondering if this would give me receiver redundancy? Eg, if one receiver failed I may be able to land with one half of the control surfaces if the other half stayed centred!... I don't know?!.... Also don't know how I would get two batteries to work both receiver's as if one battery failed then so would one receiver (if I had one battery per receiver)..... Meaning if one battery failed then the other battery wouldn't run both receivers!
I know it sounds as if I need a powerbox, but the thing is do I need a powerbox with the above Jets? Bearing in mind that there is only one servo per control surface? (I want to keep the weight down if possible)
Servo choice is another big question? Do I make use of the receiver I have and go down the HV route?.. If I do then can you get a sensor switch without a regulator? Etc.
So basically I want a soft switch to run two lipos for redundancy,
Are two receivers necessary? (if I fit the 3e gyro then I would have to stick to non sbus and use two receivers but don't know how to power them with redundancy? )
Do I need a powerbox?
Which servos? (without spending silly money)
I'd also like decent wing connectors (Eg mpx or equivalent)

I know I've wafled on terribly!, but I just don't know how to do the Installation so any advise, tips will be very much appreciated!

Rich
Old 03-03-2015, 05:08 PM
  #2  
stevekott
 
stevekott's Avatar
 
Join Date: Nov 2006
Location: yorba linda, CA
Posts: 595
Likes: 0
Received 0 Likes on 0 Posts
Default

I like simple.

My favorite setup is 2 A123 2500 LIFE battery packs and NO regulators. IHMO regulators are a weak point. I've had them go bad. An advantage with the A123's is you can use standard voltage electronics

An A123 battery pack can put out enough current to handle shorted out servos or a bad connection.

I would stick with 1 receiver. There is already a good deal of diversity built in to the Futaba dual antenna design. I haven't seen a simple way to add redundancy with the 7008SB other than like you said running half of your servos on one and the other half on the other.

I don't use SBus Servos. I like JR servos. then I drive them either with the Rx ports or the SBD-1 PWM Converters powered by the Sbus.2 port.

When you connect your incoming batteries I like to connect them at two different places. On on a heavy duty Y to the RX and another somewhere into the SBD-1 or wherever the flap servos are located. They are by far the biggest users of current.

I have used the Booma RC dual switch and the Wolverine switch. A mil-spec toggle switch is actually a more reliable choice but those electronic switches seem pretty good. I did have a Booma RC switch go bad on me one time. But it just made a solid connection to the battery and would not turn off.

To isolate the battery packs you can put a heavy duty schottky diode in series on the positive lead of each battery. That way if one of your cells short out in either battery it wont cause any drain on the other. A cell shorting out was much more common on NiMh packs. I haven't had a LiFe short out.

I'm sure other guys will chime in on their favorite setups. I've seen it done many ways and they all seem very reliable.

Happy Flying .. Good Luck!
Old 03-03-2015, 10:08 PM
  #3  
DelGatoGrande
My Feedback: (23)
 
DelGatoGrande's Avatar
 
Join Date: Mar 2004
Location: ATHENS, , GREECE
Posts: 2,994
Likes: 0
Received 17 Likes on 11 Posts
Default

yes you do need a powerbox for the battery redundancy . and for the signal amplifying for those long extensions.
The iGyro will make your model more steady and more enjoyable to fly.
Batteries go for the lipo2800 powerbox.Easy to use and overkill.Servos my favourite are the hitec 7955.

my 2c
Old 03-04-2015, 01:10 PM
  #4  
R Pursall
Junior Member
Thread Starter
 
Join Date: Jun 2008
Location: St.Columb Major, UNITED KINGDOM
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Default

Thanks for the reply's guys, very much appreciated.
what would you say is the maximum servo extension lead length you could use without the need for a powerbox?
is a 2m lead considered long?

Rich
Old 03-04-2015, 01:49 PM
  #5  
stevekott
 
stevekott's Avatar
 
Join Date: Nov 2006
Location: yorba linda, CA
Posts: 595
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by R Pursall View Post
Thanks for the reply's guys, very much appreciated.
what would you say is the maximum servo extension lead length you could use without the need for a powerbox?
is a 2m lead considered long?

Rich
I have several jets with leads that long going back to the tail. Use the heavier gauge wire.

I'm not sure using a PowerBox would affect the length you could use on a servo extension. The longer you go you will have a slight voltage drop in high current applications. That is usually compensated with larger gauge wires. But by electrical standards 2m is not that far. Servos will work fine at +5 volts they just draw a little more current. The signal wire is carrying Pulses with very little current. Normally your concern there would be inductive loss at high frequencies over distance. But RC signal frequencies are not that high and 2m is by no means too far.

Be careful on the way back to the tail you protect them from heat in the area between the back of the turbine and the bell mouth of the pipe.

I like to wrap them with a light foil tape in the high heat area. There are many other good methods.
Old 03-04-2015, 05:34 PM
  #6  
jayman618
My Feedback: (5)
 
jayman618's Avatar
 
Join Date: Jun 2002
Location: Evansville IN IL
Posts: 142
Likes: 0
Received 0 Likes on 0 Posts
Default

Just a few ideas for you. JR has a new gyro called axis and it will work with your Fatuba, sbus system. I was going to get a I-gyro myself but after JR introduced their new gyro I changed my mind because it offered several features that I wanted. The price is the same on both you might read about the Axis and see if it would work for you too. http://jrpropo.co.jp/english/dl/data/axis.pdf
Old 03-05-2015, 11:06 AM
  #7  
R Pursall
Junior Member
Thread Starter
 
Join Date: Jun 2008
Location: St.Columb Major, UNITED KINGDOM
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by stevekott View Post
I have several jets with leads that long going back to the tail. Use the heavier gauge wire.

I'm not sure using a PowerBox would affect the length you could use on a servo extension. The longer you go you will have a slight voltage drop in high current applications. That is usually compensated with larger gauge wires. But by electrical standards 2m is not that far. Servos will work fine at +5 volts they just draw a little more current. The signal wire is carrying Pulses with very little current. Normally your concern there would be inductive loss at high frequencies over distance. But RC signal frequencies are not that high and 2m is by no means too far.

Be careful on the way back to the tail you protect them from heat in the area between the back of the turbine and the bell mouth of the pipe.

I like to wrap them with a light foil tape in the high heat area. There are many other good methods.

Thanks!, I appreciate your time!
Old 03-05-2015, 11:10 AM
  #8  
R Pursall
Junior Member
Thread Starter
 
Join Date: Jun 2008
Location: St.Columb Major, UNITED KINGDOM
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by jayman618 View Post
Just a few ideas for you. JR has a new gyro called axis and it will work with your Fatuba, sbus system. I was going to get a I-gyro myself but after JR introduced their new gyro I changed my mind because it offered several features that I wanted. The price is the same on both you might read about the Axis and see if it would work for you too. http://jrpropo.co.jp/english/dl/data/axis.pdf
Thanks very much for that, I'll be sure to check out the axis!.. Sounds interesting!
Old 03-05-2015, 01:13 PM
  #9  
wfield0455
My Feedback: (7)
 
wfield0455's Avatar
 
Join Date: Sep 2005
Location: Holliston, MA
Posts: 1,284
Received 4 Likes on 4 Posts
Default

If receiver power redundancy is a concern, you certainly don't need a powerbox to deal with that. Check out Fromeco's Wolverine switch http://www.fromeco.org/products/04frcwo-430s/ if battery redundancy is your main concern. The Wolverine has 2 inputs and 2 outputs and if either battery fails or is disconnected it still powers both receivers. Simple and not much more expensive than a pair of high quality heavy duty switches. I'm sure there are others as well that offer the same features..
Old 03-05-2015, 03:46 PM
  #10  
R Pursall
Junior Member
Thread Starter
 
Join Date: Jun 2008
Location: St.Columb Major, UNITED KINGDOM
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by wfield0455 View Post
If receiver power redundancy is a concern, you certainly don't need a powerbox to deal with that. Check out Fromeco's Wolverine switch http://www.fromeco.org/products/04frcwo-430s/ if battery redundancy is your main concern. The Wolverine has 2 inputs and 2 outputs and if either battery fails or is disconnected it still powers both receivers. Simple and not much more expensive than a pair of high quality heavy duty switches. I'm sure there are others as well that offer the same features..
Thanks for the input Wayne!

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.