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Old Aug 16, 2012, 09:18 PM
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United States, TX, Abilene
Joined May 2012
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Losing Faith in JR/Spektrum

I probably should have asked this before, but is a Spektrum AR6200 DSM2 Rx NOT compatible with a JR 9303 tTx hat has been sent to JR for an upgrade to DSMX? Binding was fine, and I performed multiple 200 yard range checks with no problems.

I recently switched from Futaba, and I am begining to regret it. I installed the new system in my 27% Extra 330. Originally I used two 4.8v NiMh batteries to power the Rx/Servos, and I experienced a couple quick brownouts, but was able to land safetly. I upgraded the two packs to 6v NiMh, and also moved the Rx further back in the fuselage just in case I was get interference from the ignition, and could not get a brownout at all during my multiple range checks. I range checked out to about 200 yards both with and without the engine running (Evolution 45cc). All good, so I flew tonight, and after about 3 minutes of perfect flying my plane went full throttle and into a right hand dive straight into the ground. I had absolutely no ability to control the plane. It was a total loss. Even the Rx was broken in the crash, so I really cant even investigate. My batteries were still showing 6.4v after the crash.

What am I doing wrong? Any advice would be greatly appreciated. I am just about to finish up my new 50cc Pitts M-12S, and I am scared to death to trust it with this radio system. The only thing different in this setup will be the Rx. It will be a Spektrum AR7000 DSM2. However, I cant bring myself to trust my radio setup.

By the way, my ignition and ign battery were all mounted up front on the firewall, and my Rx was approx 20 inches aft of that. My Rx batteries were mounted approx 6 inches behind the wing tube.
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Old Aug 16, 2012, 09:38 PM
AndyKunz's Avatar
Illinois
Joined Sep 2001
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All JR DSM2 and DSMX transmitters are compatible with all Spektrum DSM2 and DSMX receivers, and vice-versa.

I'm surprised you would use that receiver in a 27% aircraft. Most guys flying that size plane would have an AR9000 in it, or one of the big PowerSafe receivers.

Andy
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Old Aug 16, 2012, 09:48 PM
60 years of RC flying
Daedalus66's Avatar
Canada, ON, Ottawa
Joined Feb 2006
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Sorry to hear about your loss.

The AR6200 certainly is compatible with a DSMX transmitter, but it will, of course, operate in DSM2 mode. Not sure why you would go to the trouble and expense of upgrading to DSMX and then use a low end DSM2 receiver in a large aircraft. DSM2 should do the job but DSMX should give greater reliability. Certainly for the new one, I would want to go DSMX, not AR7000.

I would not fly ANY new radio in a model that matters. I trust my transmitter (JR9303 still on DSM2) but I always fly a new receiver in an old model for a few flights.

You mention brownouts. These are purely a power issue and have nothing to do with signal reception. They can happen to any brand of radio. You say you upgraded the power setup, so your loss of control should not be caused by a brownout.

Don't assume that the problem is caused by the radio. More issues are probably caused by bad connectors, switches, batteries, etc.
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Old Aug 16, 2012, 09:53 PM
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Hind sight being 20/20, I should have been using a bigger receiver. I'm not sure that would be have changed what happened tonight, but it would be have been good common sense on my part.

I just read a post on a heli forum that the 9303 Tx requires a firmware upgrade in order to work with DSM2 receivers. My 9303 was originally a DSM2 Tx but was sent to Horizon for an upgrade to DSMX. I would assume the firmware update mentioned above would you have already been installed, but I'm not sure.
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Old Aug 16, 2012, 09:56 PM
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United States, KS, Overland Park
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You mention 6V NIMH batteries, but make no comment about what specific batteries. 2000 mah or higher AA cells do NOT typically have low enough internal impedance to source the current required for servos with big loads, etc. While they might measure high enough voltage with a typical ESV load on them, when they're under a real-world load they may let you down.

I've never been a big fan of NiMh batteries for that reason - they're OK in a transmitter with relatively low load current, but that's about all I'd use them for.

Your mileage may vary..
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Old Aug 16, 2012, 09:57 PM
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Joined Jan 2004
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Yes your AR6200 will work with your upgraded 9503, I use a few with mine. Even though others including Andy may be "surprised" that you used it in a largish (is 27% big anymore) it should be perfectly capable of flying it. I currently have a AR6200 in my 16 foot plane in my avatar without issue.

<---------------- this one
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Old Aug 16, 2012, 09:57 PM
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By the way, I was planning on setting up my next plane (50cc Pitts) with 7.4v LiPo packs regulated down to 6v feeding into an AR7000 Rx. Will that Rx work for my application, or should I use my AR8000 Rx? Both receivers are DSM2.
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Old Aug 16, 2012, 10:02 PM
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The battery packs that I was using tonight were 6v AA NiMh 2200 milliamp packs x2. I was also planning on using these in my 50cc Pitts, but have now decided to use 7.4 LiPo's regulated down. Please see my previous post concerning my question on receivers.
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Old Aug 16, 2012, 10:48 PM
60 years of RC flying
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Canada, ON, Ottawa
Joined Feb 2006
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Quote:
Originally Posted by Sgt Ski View Post
By the way, I was planning on setting up my next plane (50cc Pitts) with 7.4v LiPo packs regulated down to 6v feeding into an AR7000 Rx. Will that Rx work for my application, or should I use my AR8000 Rx? Both receivers are DSM2.
AR8000 is DSMX.
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Old Aug 17, 2012, 12:32 AM
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If your 9303 was sent-in for a DSMX upgrade, then flying with old DSM2 receivers defeats the purpose of getting that DSMX upgrade, no?

Before blaming your crisis of faith on Spektrum, you should first rule out if you're under-powering your receiver and servos. And then run DSMX receivers.
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Old Aug 17, 2012, 07:25 AM
AndyKunz's Avatar
Illinois
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Quote:
Originally Posted by Sgt Ski View Post
My 9303 was originally a DSM2 Tx but was sent to Horizon for an upgrade to DSMX. I would assume the firmware update mentioned above would you have already been installed, but I'm not sure.
Oh, you triggered a vague memory!

There is a Service Bulletin for early DSMX JR updates. If your PID code is TM then it needs to be updated. If you go to the DX8 web page and click on the "Important Product Bulletin" (bright red, top right corner) it has more information.

Andy
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Old Aug 17, 2012, 09:46 AM
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Quote:
Originally Posted by Left Coast DJ View Post
If your 9303 was sent-in for a DSMX upgrade, then flying with old DSM2 receivers defeats the purpose of getting that DSMX upgrade, no?

Before blaming your crisis of faith on Spektrum, you should first rule out if you're under-powering your receiver and servos. And then run DSMX receivers.
I realize that DSMX is the better way to go, however, I didn't realize that having an upgraded Tx would make all my DSM2 receivers obsolete/unusable.

As for underpowering the system, I would have agreed with you last weekend when I was getting quick/minor brownouts, and my Fail Safe feature kicked in, but was able to land safetly. The engine went to just above idle, and the controls went very mushy, but usable enough to land safelty. While researching, I realized that I was underpowering the system, hence the brownouts.

Last night was the first flight with the upgraded batteries (dual 6v NiMh AA packs). The plane flew awesome for the first three minutes of flight, but without warning the plane went into a full throttle dive with absolutely no control from the sticks. The plane was about 150' up, so I had plenty of time to react, but without any control, it ended up being plenty of time to watch my plane screw itself into the ground. It doesnt seem as if the Fail Safe feature kicked in.
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Old Aug 17, 2012, 09:49 AM
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Quote:
Originally Posted by Daedalus66 View Post
AR8000 is DSMX.
I appologize for the fat finger. The Rx that I am reffering to is actually an AR9000 which has DSM2 stamped on it and the salelite. I also have an AR7000, and a JR R922, both of which are marked DSM2 as well. After last night, I am nervous to trust any of these receivers with my upgraded JR 9303.
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Old Aug 17, 2012, 09:50 AM
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Quote:
Originally Posted by AndyKunz View Post
Oh, you triggered a vague memory!

There is a Service Bulletin for early DSMX JR updates. If your PID code is TM then it needs to be updated. If you go to the DX8 web page and click on the "Important Product Bulletin" (bright red, top right corner) it has more information.

Andy
Thanks Andy. I'll give it a look.
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Old Aug 17, 2012, 09:54 AM
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Joined Dec 2004
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"I recently switched from Futaba, and I am begining to regret it."

Can't imagine anyone switching. I got Futaba when I quit building my own, and never turned back; still fly with my 8UAF and 148 servos.

Les
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