One thing I noticed from your picture is you have your antennas are routed parallel to each other for close to half of their length. I don't fly Futaba 2.4 but Spektrum, and I make sure my antennas are routed perpendicular to each other. Not sure if could contribute or not.

Hogflyer

Yes, as hogflyer stated, it's best for the two antennas to be completely perpendicular to each other, not parallel for much of their length.

Jack

I'm trying to figure out how to manage the space in the plane to be able to do this although the manual states that the part that must stay as straight as possible is the silver tip at each end.

I believe that those sections are the only sections that are critical and should be at right angles to each other. The length prior to that is not in and of itself part of the receiving section and their routing in not critical. That's the way the instructilons for my receiver read.

The gray section of the coax can be run together, it is the exposed center that is the antenna and should be separated and at 90.

If it was me I would move the ends away from the servos, they are brushed servos if I am not mistaken.
The brushes if worn may cause excessive sparking under load which may cause RF noise. Random RF noise that close could swamp out the real signal resulting in failsafe, then the servo motors stop moving, the RF noise goes away, signal is now good, regain control. I am not saying this is the problem, just something I would change.
Need more info and debug-testing.

I have my antennas exit the fuse at 90 degrees and they
are perpendicular to each other also. Just a thought,

Bob

Yes, the idea of one antenna being perpendicular to the level flight plane has been suggested a few times and it's something I'll definitely correct.

WOW, that's harsh. Just 2 guys?

You should read the other responses.... They're knowlegeable too.

You're absolutely right, everyone has been really helpful. Sorry

How much clearance do you have between the antenna tips and your pushrods? I don't have the manual handy at the moment, but I know there's supposed to be a minimum clearance of around 1/2" to an inch between them and any metal parts to prevent interference. It seems like yours are really close.

EDIT: I had a similar situation on my mid star with everything packed in pretty tight. I ended up mounting one antenna vertically on the fuse former behind the fuel tank and the other antenna was horizontal on the left side of the fuse to keep it away from the throttle linkage in order to get the proper antenna clearance.

Could you have had the antenna (TX) pointed directly at the plane without noticing?

How much of a problem is this? I have noticed it with my Spektrum surface tx, but never with my Futaba or Spektrum air systems.

I have taken that into consideration for my new setup. You're right, the manual states at least 1/2" of clearance with metal objects.


The manual states to try and point the Tx antenna towards the floor (Perpendicular to the face of the radio) so it was definitely not pointing it at the plane.

Look at this service advisory on Futaba's web site

http://2.4gigahertz.com/techsupport/...m7-7c-6ex.html

Not sure if that is the issue but maybe worth looking into

Thanks jayjast but my Tx is a 10C, that advisory applies for 6 and 7 channel transmitters and modules only.

I've done all my radio setup again inside the plane. The following images show my workaround to the possible antenna blockage. I've placed half the battery under the servo tray and I made a retainer for the battery which I fixed with short screws to the servo tray. It's L shaped just in case it's not noticeable on the pictures so it will hold the battery in place which is still wrapped in latex foam. I re routed the servo cables through the hole in the servo tray and run them down the vertical face of the battery retainer. I glued in place some standoffs for the Rx so it wont crimp the cables. A rubber band holds the Rx in place. Now the important part. The antennas I routed one at each side of the fuse, still at 90° but this time one goes along the travel axis of the plane and the other one is perpendicular to that axis. Any comments or suggestions on the new setup I'll appreciate greatly. (The first picture is the old setup for comparison purposes)

Obviously something happened, you have checked the equipment and found nothing; that leaves intermittent equipment failure or RF interference or it could be there is nothing wrong with the equipment and the RX lost sync with the transmitted signal for no repeatable reason.
While many hail spread-spectrum as the holy graile, the fact is no RF transmission is bullet proof.
These things are very hard to troubleshoot in person much less on an internet forum.
Unplug everything and then plug it back in, replace the switch in the plane, on the TX if the antenna is connected to a board with a screw, loosen it and then retighten it, look at the solder connections .... once you check everything and do a 10 - 20 minute range check the only thing left to do is to send it back or fly the plane again.

Hello plugin
I too had a strange failure with my Futaba 2.4MHz controlled plane. It was on my SPAD Flying Lawnmower. The plane was about 4 years old and had been using this newer radio for about 18 months. I lost all control during a climbing turn and the plane slowly dived into the ground from about 50 feet up, with no controls working. Afterwards everything worked. After a few weeks of thinking about it I replaced the On/Off switch with a heavy duty switch that also used gold plated contacts and cost about 2-3 times that of a standard switch. For good measure I also discarded the Rx battery and some extensions and a mixer for the elevons. The receiver is now my new Spad Biplane and all has been well. In the absence of any evidence I am putting all the blame on the On/Off switch and am slowly converting all of my planes to use the better switch. I would not place the receiver on top of the battery like you have. I once had glitches with one of my older Futaba radios and eventually I eliminated them after I put about one inch between the battery and the receiver. I currently have four of the 2.4MHz receivers on 4 different planes. On all of my planes the radio antennas are much better separated and at close to 90 degrees from each other in their full length than is shown in the photo you provided. Many of my planes use aluminum angles or square tubing so I have to be very inventive to keep the radio signal from being blocked. Buena suerte, amigo.

plugin:

It seems to me that the RX could have been exposed to direct vibrations from the frame through the black strap, regardless the foam that may have been underneath.

Try to isolate the RX completely from the frame in the new layout, which I don't see now.

Also, always range check the radio system with the engine running at low and high revolutions, and standing as far away from the model as possible.

I believe you should be careful and prepared for an emergency in the following flights, but not too afraid.

Regards!