Hi all,

Here's my plane's configuration (all is brand new equipment):

Funtana
OS 46AX
4 x JR 537 servos (2 x Ail, 1 x Elev, 1 x Throttle)
1 x JR DS811 servo (Rudder)
JR R700 receiver
JR XP8103H heli radio
JR Extra battery packs (either 4.8v 1100mAh or 6v 1100mAh)

I finished building my Funtana 4 weeks ago and have been trying to fly it ever since. So far, I have not even taxi'd it out onto the field and it has all to do with radio problems.

When I switch the plane on at the field I get incredible flutter off the ailerons and elevator. When I switch the plane on at home, I don't get any flutter at all.

After my first trip to the field, I went back to the hobby store to complain. They told me they suspected the 537 servos, that they would replace them, and I should try again. I did this. Didn't help.

Next I had a couple of the instructors at the field look over the plane. They suspected that the wires were crossed over and causing interference. We changed the wiring, hung the receiver's antenna away from everything. No luck. They suspected receiver.

I went and bought a new R700 receiver. Installed it in the plane and took it back to the field. No help.

I went back to the hobby store. Explained the configuration again, including the fact that the servos (all except the throttle) are on extension leads. They suspected that the voltage was not sufficient for the plane (I was running on 4.8v). "Get a battery pack with higher voltage." $35 for a new battery pack. No luck. Flutters like hell at the field. Nothing at home.

When I say "nothing at home," I mean that there is not even a buzz coming from the plane. Not a sound. Responds to all controls, even if I go stand outside and try and control it.

I don't know what to think anymore. I'm at a total loss.

I should also note that I have three other planes and a heli all flying off this radio. I have no buzzing on any of the other aircraft. The three planes all have R700 receivers and the heli has a JR NER 649S SPCM receiver in it. None of these have a problem at the field.

What I have noticed is that at the field, if I leave the plane on for a while (4 or 5 minutes) the flutter seems to lessen, almost to the point that it stops. At this point, if I apply any pressure to the control surfaces, it will flutter briefly and then settle.

I have tried this with fully charged batteries and batteries that are somewhere between full and half (I have a voltwatch in the plane to check this).

The aileron servos have 12" servo extension cables on them and the elevator has an 18" extension. The rudder has a 12 and a 6.

The only thing that I am left thinking is that the cold weather has something to do with this. At the field the temperature has fluctuated between 4F and 20F during the time that I have been trying to do this. I know... it's been bitterly cold. I have not had the pleasure of a day where the weather got above 20 in goodness knows how long.

At home the temperature is somewhere between 65 and 70F inside.

I have a theory that the cold weather outdoors increases the static electricity and that this, combined with the servo extension length may have something to do with the problem. The problem with that theory is that one of my other planes is an Ultra Stick 40 with 7 servos, 4 in the wing. It has extensions on all 4 the wing servos and I don't hear so much as a hum from those servos. They are Hitec servos, though, so it's not an apples-to-apples comparison.

I'm really hoping that someone out there has some insightful words to share with me on this.

Please help!!!

regards,
Bruce

Wierd,

Try to change your channel, probably interference around your field.

John

I would buy that except that I am flying the other three planes and my chopper on the same frequency.

regards,
Bruce

Very interesting. There must be some other factor that's different between home vs field, or close enough that the temperature difference amplifies an exisiting issue.

Have you tried it at home, but outside? (To isolate between temp and something at the field location)

Have you tried detaching servos, one by one, at the radio? (To check for a servo issue)

Have you tried changing Rx antenna location, 90 degrees to long servo extensions?

Does it matter how the Tx is positioned when the flutter occurs? ie, does pointing the antenna in a certain direction or moving to a different position change the flutter frequency or amplitude?

Have you twisted the servo extension wires? (I'll probably get grief over this, but I will never again use extensions without twisting them first - it will cause events similar to what you describe, it has happened to me)

change your extensions . jr is bad for very picky servos . ment in a good way . i fly only jr . that was my problem one time . anything over 2 foot i use fiber optic . not needed i hope . but they don't refund your money for crashes .

Yup. No luck.

Uh huh. The minute I plug in any one of the aileron or elevator servos at the field, I get flutter, even if it is the only servo plugged in, and even if I plug it into the rudder or throttle port.

Yup. I've even moved the receiver and batteries around and messed up the CG to try and get it to stop. No luck.

No. A buddy of mine and I were trying this the other day with no difference. I walked about 100 yards from the plane with my back turned and the antenna down on the Tx and it made no difference which way I pointed the Tx, the flutter persisted.

You are the second person that has suggested this to me. When the other person suggested it, someone who was with me told me that it was an old wife's tale and that there was no validity to it -- someone whose opinion I respect.

I am now at the point where I don't know what to do anymore. I have pulled out some of the extensions and put shorter ones in this evening and I'm going down to the field in the morning to see if that makes a difference.

If it doesn't, I'll try the twisting thing. I'm at my wit's end at the moment and I'm now willing to try anything!!

Thanks and regards,
Bruce

Did you try a different Rx crystal?

Yup. Complete new receiver and crystal. Same problem.

Same thing happened to me w/ my UCD60. I tried everything!! Swapped servos, crystals, extentions, switches, batt paks, locations of everything and even took my complete flight pak out and laid it out onto a piece of board, in the same configuration as it was within the plane, so that I could move the anntenae around. I even tried a different Rx from another plane and the problem continued. couldn't fly the plane for 2 months after completion


***Turned out that I somehow had fried both receivers. One, with a bad 4.8v pak and one with an unregulated 6.0v pak. If you're gonna' use 6v's, regulate the pak.

Hope this helps and good luck!

Another thought, bypass the switch altogether. Just plug the batt pak directly into rx and see what it does.

**Both my Rx's (JR) were toasted immediately, as soon as I turned the switch on, both times!!

My funtana did the same thing. The first problem was a bad r700 receiver. I tried a hitech receiver and it stopped immediatly. I still get a hi-voltage (swamping) when I first turn the [lane on with a fresh charge. I am a diehard jr man having both an R1, and an 8103, but that r700 is a POS receiver. I would give Horizon a call, ask for JR service. Good Luck. Ron

A company called i4c products makes a great servo isolator that only weighs about one ounce
and is about the same size as your receiver. It lets you run your servos on 6 volts and your receiver
on 4.8 volts (what is was designed for) but the good part is it isolates your receiver from outside
interference from long servo leads etc. The battery for the receiver does not need to be very big
as it uses very little current without the servos.

tommy s

The receivers are not fried because if I hook them up in one of the other planes, everything works great.

Tommy,

Any idea where I can get it from on-line, or is my local hobby store likely to have it?

I've never seen them in a hobby store. They have a web site but you have to call
to order. I have one and they work great.

www.i4cproducts.com

tommy s

Just looked at web site / they do have on-line ordering now.

Have you isolated the switch? I had this happen to me due to a bad switch.
Hope you get it figured out.

Mike

I have 4 R700 FM receivers and two of the new 700 PCM recievers. They are absolutely bullet proof. I run them all un unregulated 6V packs and after hundreds of flights, they have all run flawless. I even have two of the FM units in Gasoline powered planes and have not had a single issue.

Are you using a JR Switch?

It is possible your LHS has received 2 bad receivers (although unlikely) are you ABSOLUTELY CERTAIN the LHS gave you a new crystal. Sounds to me like your receiver is getting hits and it could be due to a oscillator freq shift.

You have done everything each of us would have done with the exception of changing channels and using a different brand or model receiver.

I forgot to ask - is the engine running ? I am assuming you have not ever gotten that far yet?

DP

I have no doubt that it is not the receivers. I have moved the receivers to other planes afterwards and not seen anything untoward happen.


Yes. It's a brand new one. I haven't swapped that out, gut I would think that if I don't see the problem at home, it is unlikely to be that. I'll swap it out and give it a try.

The first receiver was brand new. The second receiver came from a plane that has been flying fine. I took it and it's crystal together and swapped them out lock, stock and barrel. IOW, when I swapped it, the crystal went with it.

Changing channels is a problem because I'd need to change the channel of the receiver and I believe that is a bigger issue.


And I forgot to mention that I have broken the engine in on this plane's fuse. Whether the engine is running or not I see the flutter at the field. When I broke the engine in, I disconnected all except the throttle servo because of the flutter.

Thanks for your reply. You guys have all given me stuff to think about and at least validated that I am thinking about the right things.

Just a thought. Have you built any Carbon Fibre into the plane that runs parallel to any of your servo leads. I've had a similar problem with an all moulded glider with carbon spars.

Ian.

Can i just say, allot of JR servos dont like to run at 6v

Ian,

I have carbon fibre landing gear and the two carbon fibre spars supporting the horizontal stab. The spars in the stab run perpendicular to the plane that the servo leads run on, but they are behind the rudder and elevator servos and therefore not close to the servo leads. The landing gear is under the fuse and forward of the servo leads for the aileron servos. A portion of it runs perpendicular to the wing, but it is a good 3 or 4 inches below the wing and well insulated with plenty of wood in between. Do you think this could make a difference?

Thanks for the input.

Even though they are rated at 6V? That doesn't make sense. I asked Horizon about this and they did not think it was the problem, especially seeing as I saw the same problem with a 4.8V battery before.

I believe in this wife's tale! My Funtana was doing the same thing you are describing. My fix was to use heavy duty servo Extensions. I also twisted the extension. I had picked up some JR servo extensions at a swap meet cheep! I got the good ones at RadicalRC!
Victor

My Funtana had the same problem..I found the problem was antenna location..I had run the antenna inside a tube inside the fuselage..the wire had doubled up inside the plastic tube and caused interference by way of the two servos mounted in the rear..relocated outside and the servos are steady now....

I have always run my futaba r700 with a 6V pack unregulated. Never any problems. One thing i do like to do is stay within brands. I use futaba receivers with futaba servos. I would suggest trying different servos, as you have eliminated the idea of the RX or TX. A guy i fly with has a funtana with saito .72 BK using a 9CAP tx and not sure of RX but he uses JR servos, 2 weeks ago he had the same problem. His servos fluttered around the neutral point and eventually would stop fluttering, but it wasn't a violent flutter, just a little "wiggle". I think his ailerons did this because they are massive and have alot of weight. He decided to fly it (maiden) and had absolutely no problem. we also noticed if he put his finger under the aileron and push-up a little, toward the center, it would stop at neutral. We figured the airflow over the surfaces helped the ailerons center in flight. He had an uneventful flight and made a smooth landing.

If you want to know, not relevant to topic but:

Personally i use the r700 RX, T6XAS TX, S3004 servos all around (changing soon), and a 46FX with slimline pitts muffler. I like this plane with the .46, many will say otherwise, but it flies at a good speed, but wont go near overspeeding in straight flight at WOT, always throttle back on decent to prevent over speed. Aerobatics a great, with a .46 on the nose it fly's like a sport plane on steroids. It waterfalls nicely, snaps great, does spins (still working to get flat spin), stall turns, whatever, just dont expect to do 3D with the 46. I run an APC 11x5 sport prop with omega 15% nitro fuel. I can just about get it to hang at full throttle, but i wasnt it expecting it to with a .46 walls and elevators are done easily, as is the heart attack (do one inverted ). It will perform just about every move with the .46, just not the stalled wing maneuvers, i have yet to try a harrier, but i dont think it will do it at too slow a speed or too great AOA.
Just thought you would like to know this stuff before you flew it, happy flying, hope your problem gets fixed, HAVED FUN!!

sean