jster1963

Hi,

Engine: Enya .35
Radio: Futaba FP-7UHPS (Super 7 PCM 1024)
Gyro: Futaba FP-G154
Extra: FMA Copilot

My ZXX is losing signal as soon as the engine starts. With the engine off, I have no signal problems at all. So I know it is on the heli. I've had this heli since 1994 and never had this problem.

I had not flown in 4 years (I have a 4 yr old), and thought I would fly it again. I bought new batteries and filled it up and it flew like a champ. I did notice the clutch lining coming out, so I pulled the engine and JB welded the lining back in. It was too tight so I pulled the engine again to fix that. This is when the problems started.

At a 3 ft hover it lost signal and hit the ground in soft grass on the skids with no damage. I assumed low batteries on the tx because it read 9.6v. I charged the batteries and tried it again. This time at 5 ft above the ground it lost signal, climbed to 10 ft, rolled to 135 degrees and plowed into the ground. Even crashed on the ground with the engine off, the servos worked fine.

I rebuilt it, tied it down and tried again. Same thing. As soon as the engine starts, the tx has no affect on the heli. This is a new one for me so I searched the forum and one possibility is a dry bearing.

Does anyone know what bearings could be causing my problems on the ZXX? Also, my rx antenna is away from other metal like it has always been.

I did notice when I removed the remote wire from the glow plug, I got control back for a minute or so, then lost it again.

Any help would be appreciated. Thanks.......jster

mrc-hirobo

I would suggest checking the following:

1. Insure your battery connections on the model are tight and are not vibrating loose when the engine is running

2. If the servos, receiver and transmitter are very old I would suggest sending them in to Hobby Services to be tested, retuned and/or reconditioned

3. The clutch shoes to clutch liner should not be a tight fit. You should have a clearance/gap of about 0.5mm. To install properly, take the clutch show and wrap it twice with electrical tape so that the top edge of the tape is flush with the top of the clutch shoes, then clean out any old glue on the clutch bell, clean the inside of the clutch bell with acetone or other cleaner that doesn't leave any resideu, mix up some 30-minute epoxy and put a smear coat on the inside of the clutch bell, then carefully insert a new clutch liner making sure the ends cleanly butt up against eachother, then slowly push the clutch shoe assembly in place and let it fully cure. The electrical tape will press the liner in place and set a proper gap.

4. Check and/or change your glow plug. Also insure that your glow extension is not intermittant, if in doubt, replace it.

5. Load check your receiver pack to insure its good

6. Make sure your engine bearings are in good shape. MRC no longer carries parts for Enya, so if you need anything for that motor you'll have to go to Enya directly

7. Make sure your receiver crystal is tightly secured in the receiver. If it is loose, you may lose reception when it is exposed to the engine vibration during normal running.

8. Check to make sure your receiver power switch is not intermittant, old or fuel soaked. If in doubt, replace it.

That's about all I can think of. If all that stuff is good, I think you'd be in pretty good shape.

jster1963

Thank you so much for your reply. Now I must show my ignorance about a few things.

#4. The engine runs great. Could the glow plug still be bad? If so, could it cause a signal loss problem?

#6. How can I tell if I have a bad engine bearing? The engine seems to run fine.

My receiver is a Futaba FP-R129DP

#7. Where is my receiver crystal? There is a small aluminum looking thing in the bottom of the receiver. It has a sticker on it with writing on it. The unit seems sealed with 2 small screws in the bottom.

#8. Where is the receiver power switch? I don’t see one on the unit.

I will do the other suggestions. Thanks again……jster

mrc-hirobo

4. a bad or loose plug can cause RF noise

6. turn the motor by hand and feel for any roughness, otherwise you'd hear a noise when running

7. yep, that's likely the crystal, check to make sure it is secured

8. how do you turn on power to your model? if its with a switch, that's it!

jster1963

Thank you once again. I will try all of the above. When I know the problem, I will post it.


Thanks again........jster

nitrohog

My bet is on a bad RX power switch or wire. When you said that you removed the remote glow igniter and it helped I bet that you moved the switch wires considering their location. Also sitting for 4 years could have caused some corrosion.

jster1963

Thank you.

My father always told me to start with the simple/cheap things first. I will check that first. I have tickets to a Michigan State football game this weekend, but I will check that the minute I get back.

Thanks again.......jster

jster1963

Here is the latest.

I changed the glow plug but as soon as the engine started, I lost sighal again. Then I connected the receiver battery directly to the receiver and had the same problem. So.. I ruled out the glow plug and the switch.

I restarted the engine and pulled the remote glow plug adapter off the glow plug and got the signal back again. I had the signal for a minute or so, and then it glitched (the servos hesitated for a few seconds, then started working again).

The weird thing is when I pulled the remote off the glow plug and the signal came back, I tried putting it back on, and it continued to work as if it were off (it glitched a few times a minute). The remote glow plug adapter has a ground to the engine and the other to the glow plug.

I then pulled out the crystal and put it back in. It was tight. Am I missing something in my home trouble shooting? Does the remote glow plug adapter pulled off give another clue? Please let me know if does. I want to go buy things tomorrow. If I need a new crystal or remote glow plug adapter, I want to get everything at the same time.

Thanks again........jster

jster1963

EUREKA!!!!!!!!!!!!! I accidently found my problem.

I am waiting on some parts, so I took apart the electronics and something caught my attention….THE BATTERY CONNECTION. I did not buy the Futaba battery; I bought a Tenergy battery because it was the same voltage, capacity, and “connection.� After I took a good look at it, the connection “holes� were 2-3 times the size of my Futaba battery.

I cut the connector off of my old Futaba battery and connected it to the new battery. No problems. HAAA….LAY…..LOOO….YAHHH!!!!!!! It was a loose battery wire even though the connection was tight.

THANK YOU, everyone, for all of the help. I will make a post it I find something new. Take care…..jster

jster1963

My victory dance was too soon….

I tried to fly today and the problem is back. As soon as I started the engine, it went into fail safe. I did not cinch all of the wires down because I did not want to rip it apart again if it glitched again. WELL….it did.

I have parts coming this week. I am replacing the remote glow adapter, however I’m not sure that is going to help now. I am sooooo confused.

Oh well, I will update when I replace the remote adapter, oil the bearings, and re-route the wiring.

Take care…….jster

nitrohog

I would be tempted to point my finger at the crystal at this point. They will sometimes be intermittent before they go bad. Another thing that comes to mind is the Trex 500 guys and their static electricity problem and similar symptorms with the tail belt, they use food grade silicone to lubricate the tail belt and minimize the static. I don't see the remote glow adapter causing that much trouble, especially because it is dead weight after the engine is running.

jster1963

Thanks nitrohog. This has been a weird experience for me. I am usually the limiting factor in my flying. Now it is some weird glitch.

I will get a new crystal today if the LHS has one. I don't think it is the belt because when the engine starts, the belt is not turning. I will keep that in mind if it happens in flight.

Thanks again. I will post as I learn more........jster

jster1963

OK,

I put in a new crystal. SAME THING!! As soon as the engine starts, it goes into fail safe which I have setup right now to kill the engine. As soon as the engine stops, the servo control moves the throttle right back to idle. I watch the throttle do it every time. It's killin' me. I bought some electronic contact cleaner and will clean every contact and try again when I get back home. I am on a business trip and won't get to mess with for a week.

If anyone has any other ideas, PLEASE let me know.

Thank you......jster

jster1963

As the world turns...continued.

I cleaned all electrical contacts with contact cleaner. I re-ran all the wires, and all looks well. The antenna wire looks secure on the circuit board as well.

However, with a new crystal, and all clean contacts, I still have the same problem.
I decided to remove the engine to check bearings. I found something interesting.

The clutch bell on the ZXX is on a hollow shaft with a gear to start the engine. The hollow shaft has "play" in it relative to the bell. It can turn about 1.5 mm back and forth.

Is there supposed to be any "play" in that hollow shaft? If not, can I green locktite it? Any help would be appreciated.

Thank you.....jster

nitrohog

Any way you can point out which part is loose. Ill try to help, but I have a Shuttle Z which doesn't have the shaft start. I will attach a couple of pics from the manual.

jster1963

It is part number 402-520. It is a single piece that looks like it is made from 2 pieces. There is a little twist/play right where the gear touches the bell. I think it is not supposed to have any play in it. I think that happened when my clutch was too tight and I held the head when the motor revved to keep the blades from spinning.

Thank you for your reply and I hope we can get this figured out. If no one knows, I think I will locktite it and give it a try.

Take care......jster

mrc-hirobo

if the pinion is loose you'll need to unscrew it, clean the threads, then apply some red loctite.

jster1963

Dan,

U the MAN. I did not even realize that was a 2 piece item. It came as one and the book only shows it as one. As I was cleaning it for locktite, it unscrewed. I now see what you are talking about cleaning the threads and red locktiting it. I will do that tonite and report back when I put the engine back in and try it.

Thank you so muck. More later.......jster

jster1963

I'm ready to Punt, or slit my wrists...

I used red locktite on the clutch bell housing, lubricated everything and put it back together. SAME THING. I then removed the engine, and installed a new engine. I thought the engine bearing may be bad. With the new engine (I had a spare) installed, SAME THING.

I'm at a loss. Does anyone have any advise before I jump off the bridge?

Please help. Thanks......jster

nitrohog

Sorry for the late reply feel free to shoot me a PM anytime if I miss another post. I would turn on the electronics and go around the heli tapping anything and everything that could be rubbing metal to metal and causing interference. Also I just had another thought, could it be that your failsafe is failing?

jster1963

Nitrohog,

WOW. I never thought about the failsafe having a problem. I will look at that.

I sent my receiver in for an overhaul a couple of days ago. When it gets back, I will do a full check. If there is a problem, I will disable the failsafe and try again.

Thanks for the reply and I will update when I get the receiver back. Take care.......jster

nitrohog

The only reason I thought of that is I had a failsafe cause a lot of havoc in my Tmaxx, I have never used one since. I hope the RX rebuild helps.

jster1963

I can't remember the sequence of events, but it is very close to me turning on a few things in my radio that I had my trouble. Failsafe is one of them. That would be so ironic; the failsafe "killing me". If that is the problem, I will be both happy and sad. Happy that it is a quick fix, sad that such a simple thing has caused me so much trouble.

I'll keep you in the loop. Thanks again.....jster

glydrjocky

Hello Jster,

Sounds like your on track to fix your ZXX. Im curious if the clutch liner was ever replaced and properly bonded after it came loose initially. I had a friend at the field who once bonded in his liner without properly taping the clutch and installing the taped clutch inside the bell to hold the liner in place until the JB weld cured. He also ended up with a tight clutch that caused him a great deal of vibration. I'm curious if the clutch problem you had initally did some vibration damage to the receiver? The bell coming loose from the spindle is very suspect to the liner not being bonded uniformly.

I recently had my clutch bell (steel type ZX one piece) crack out around the spindle to bell spot welds. I pulled the engine and did the hub runout check for the heck of it. This heli was an ebay special and I wasnt the one who put the fan hub on. I was astonished to find almost .006 run out on my fan hub. The ZX fan and hub do not screw on, they just slip over the engine shaft and the nut holds the works in place. I used a few wraps of tape to help hold a better center as I bolted the hub/fan back on and was able to get .001 after a few tries. I then dial indicated the clutch itself right at the fixed portion where the two main attach screws go in. I found .003 offset here. Pulled the screws and turned the clutch 180 degrees and the run out went to .000! Needless to say I have a substantially smoother engine and the gyro holds better now that the vibes are under control.

While your waiting for your receiver you might want to replace that whole clutch liner, check clutch bearing, and dial indicate the clutch/hub/ fan runout. The ZXX might have a screw on fan with collets which makes for a much more precise centering.

When things are turning 17,000 rpm, the things that I used to think really didnt matter that much ..........really do matter that much!

Hope you get things up and running Shuttles are alot of fun!

Tony

glydrjocky

whoops double posted

Which begs the question...........how does one remove a double posting????