FrSky conversion of JR XP7202

If you've been building electronic bits or modifying stuff you've bought then tell us all about it here. A good place to discuss the installation of 2.4GHz DIY modules too.

FrSky conversion of JR XP7202

Postby BobAZ » Tue Jun 29, 2010 5:20 am

I had converted my JR XP7202 to 2.4 GHz from 72 MHz by using the RF from a Spektrum DS9 module. It worked fine using a Spektrum AR7000.

I purchased the FrSky DIY RF module and 8 channel receiver thinking that it would be better since the FrSky has frequency hopping and the Spektrum is DSM2, which in a review on RC Model Reviews indicated that the two frequencies chosen could be so close that they could both be "wiped out" with an outside source.

However, on my second day of flying on the second flight, I lost control of the plane (Parkzone Trojan T-28D). I thought that it was due to winds causing the plane to balloon up and stall. It landed upright and with minor damage. So I repaired the plane and took it out today. The first flight was fine, but on the second flight I could not roll the plane to the left. I lost control and it flew away. I searched the area were I last saw it (trees near an apartment complex). Could not find it in the trees or anywhere around the complex.

So I am not very impressed with the FrSky system. I had flown the 7202 for a couple of months with the AR7000 and never had any radio problem. Three day of flying with the FrSky and I had two days of radio problems with the loss of an aircraft.
BobAZ
 
Posts: 26
Joined: Tue Jun 29, 2010 5:02 am

Re: FrSky conversion of JR XP7202

Postby RCModelReviews » Tue Jun 29, 2010 7:54 am

What receiver were you using?

Did you do a power-down range-test before flying?
RCModelReviews.com, just the facts.
User avatar
RCModelReviews
 
Posts: 2120
Joined: Tue May 04, 2010 3:40 am

Re: FrSky conversion of JR XP7202

Postby BobAZ » Tue Jun 29, 2010 4:35 pm

Yes. The first time I took it out to fly, I pushed the F/S Range button to reduce the range. I was able to walk about 74 yds away an still have control input. Since the instructions indicated 30 m, I figured that I had more than enough range.
BobAZ
 
Posts: 26
Joined: Tue Jun 29, 2010 5:02 am

Re: FrSky conversion of JR XP7202

Postby RCModelReviews » Tue Jun 29, 2010 9:55 pm

So what receiver were you using? The only problems I've heard of are people using the 4-channel receiver in models where they may get some shadowing of the single short antenna.
RCModelReviews.com, just the facts.
User avatar
RCModelReviews
 
Posts: 2120
Joined: Tue May 04, 2010 3:40 am

Re: FrSky conversion of JR XP7202

Postby BobAZ » Tue Jun 29, 2010 10:32 pm

I was using the 8 channel (V8FR). It was the PNP Trojan T-28D which has 2 aileron servos, elevator and rudder. It comes with a 30 amp ESC. I still had the original prop on it. I had flown it for about a dozen or more flight using my Futaba 8FG TX and 7 channel receiver – never a glitch. I had converted my JR XP7202 to 2.4 GHz by using the RF out of a DM9 module and AR7000 receivers. I never had a glitch with that either. But when I got my 8FG I stopped using the 7202. When I saw your reviews on the FrSky system I thought that I could "upgrade" my 7202 to frequency hopping and sell the DM9 module and AR7000 receivers.

I had one of the antennas going straight back and the other one going out the side of the Trojan fuselage – that is what Futaba recommends for their 2.4 systems.
BobAZ
 
Posts: 26
Joined: Tue Jun 29, 2010 5:02 am

Re: FrSky conversion of JR XP7202

Postby RCModelReviews » Tue Jun 29, 2010 10:40 pm

If both antennas were at least 2-inches clear of batteries, extensions, motor, servos, etc then everything should have been fine.

Of course there's always the possibility that you have a faulty module or receiver -- it happens regardless of the brand.

Did you have the failsafes set? DId it go into failsafe or just lock-out completely?
RCModelReviews.com, just the facts.
User avatar
RCModelReviews
 
Posts: 2120
Joined: Tue May 04, 2010 3:40 am

Re: FrSky conversion of JR XP7202

Postby BobAZ » Tue Jun 29, 2010 10:50 pm

I did not set fail safe. So unless it was originally set from the factory, I didn't have fail safe. The receiver was in exactly the same position as my Futaba 617 seven channel receiver had been. I had flown it originally with the 7 channel receiver until I put the FrSky in. I noticed that it was not responding when I tried to put in left aileron. I raised the TX as high as I could get it, but could not get the plane to respond to any input. It just continued to fly away. I searched the trees where I last saw it and the adjacent apartment complex, but never found it.
BobAZ
 
Posts: 26
Joined: Tue Jun 29, 2010 5:02 am

Re: FrSky conversion of JR XP7202

Postby RCModelReviews » Tue Jun 29, 2010 11:02 pm

This is why I always encourage people to set the failsafe in their RC gear.

If you'd set the failsafe to turn the engine off with loss of signal you'd be better off because:

1. if the problem was a loss of signal (faulty Tx module or interference) then the model would not have flown away.
2. by seeing whether failsafe kicked in you'd be able to tell if it was the receiver at fault or not.

The default failsafe is "last position hold" which means you can't tell whether the receiver has simply stopped working (but is still sending valid pulses to the speed controller) or whether it's a true loss of signal.

Am I correct in assuming that you have installed a DIY kit in your transmitter or does the 7202 have a module?
RCModelReviews.com, just the facts.
User avatar
RCModelReviews
 
Posts: 2120
Joined: Tue May 04, 2010 3:40 am

Re: FrSky conversion of JR XP7202

Postby BobAZ » Tue Jun 29, 2010 11:40 pm

You are correct. The 7202 does not have a module and therefore I installed the DIY RF.
BobAZ
 
Posts: 26
Joined: Tue Jun 29, 2010 5:02 am

Re: FrSky conversion of JR XP7202

Postby RCModelReviews » Tue Jun 29, 2010 11:51 pm

That tends to rule out a faulty module-fit. Do you have any pictures of the installation?

Was the transmitter LED still red and flickering after the model flew away? There's no way you could have an accidental short on the bind/range-test button that could have switched it into range-test mode while you were flying?
RCModelReviews.com, just the facts.
User avatar
RCModelReviews
 
Posts: 2120
Joined: Tue May 04, 2010 3:40 am

Next

Return to DIY Projects and Hacks

Who is online

Users browsing this forum: No registered users and 1 guest