polygoo

Hey guys, I was out flying my caliber 30 today for one of the first times, Which by the way went extremely well, the caliber flys great... anyway, I noticed a strange radio glitch at certain spots. For some reason everytime I was up in the air and started to drop the throttle stick, the helicopter would twitch for a split second, it wasnt major but i'm worried it will get worse and cause a crash of some sort.

I kept trying it over and over again and almost every time it would glitch at the same throttle position. It was usually when I was bring it back into a hover after coming from forward flight.

I am going to look over the helicopter tonight to see if I can find any metal on metal vibrations that could be causing it, but in the mean time does anyeone have any ideas as to why it would only do it at a certain rpm?

Thanks a lot, I cant thank everyone enough for all the help, this site has been a major part of my new hobby.

P.S. I am using a Futaba 7c, with a non-pcm (PPM) reciever

Maybe I should just upgrade to a PCM reciever and it will go away?

1ight

Can you repeat the glitching w/ the engine off ? I'd try to turn the receiver on and slowly work your collective. Maybe there is something wrong w/ your radio at a certain stick postion? Wont hurt to try that ... see what happens.

polygoo

well i'll have to try that, thanks for the suggestion. one thing i did notice is that I had my antenna wire for the RX coiled next to a few receiver wires/power wires, maybe thats what was causing it. I'll have to try tomorrow and see if its gone.

Thanks

wisdom-seeker

Never, repeat, never coil your antenna. It can severely reduce your range, and it can make your receiver sensitive to changing magnetic fields.

polygoo

hey guys, i'm back with some results, and have some new questions if you dont mind.

I looked over my caliber 30 and made sure that no wires were near the RX wire, I removed all coils from the wire, made sure that the wire was ok, took out any crimps, etc... tightened my tail rudder control rod to remove a slight vibration... and rubber mounted all of the servos. I went out today to fly it and all was exellent, but then i got one small glitch but I couldnt repeat it at all, it seems like this are definetely better but I still get a very small glitch every once and a while, not enough to even notice when in forward flight, but enough to notice when hovering.

My question is: Should I just switch to PCM?

i've heard that PCM is better for filtering out glitches, although (without starting a PPM VS. PCM debate) is it bad to switch to PCM to resolve a glitch issue?

My heli is in tip-top shape, and i've only had it for a short amount of time so I am begining to think that this glitch is actually from a nearby very small airport which I am flying about 1-2 miles away from, because it sees that the glitch comes and goes depending on where I fly it. Should PCM correct the problem?

Thanks alot guys

-pkh-

My Feedback: (2)

If I had glitching like that, I'd definitely switch to PCM. It will reject glitches like that much better than a standard PPM receiver.

I fly PCM in two of my three nitro choppers... never had glitching problems with them... but I've not had glitching problems with my PPM yet either!

polygoo

OK thanks alot for the tips, I think I am going to get a PCM reciever, my radio already supports it so I should be good to go. I just hope i'm not masking some deeper problem, although the glitch is extrememy minor, so I think i should be alright.

BarracudaHockey

My Feedback: (11)

Whats glitching? Tail rotors can act squirlley when the engine is running rich making it look like a glitch.

polygoo

it can?? Maybe thats the problem i've having. basically, when i'm hovering, every once in a while the tail will move a bit and the entire heli will sort of "jump" or "roll" about 1 inch in a random direction

I was running it a bit rich the other day actually, maybe thats whats causing it, I also did notice that my tail was acting strange.

polygoo

my friend was filming a video when I was flying, I actually got the glitch on video,

http://www.polygoo.com/cal_glitch.avi

if you look really closely, you can see a slight "jerk" towards the end of the video, it happens, and then I fly start to move the heli up.

BarracudaHockey

My Feedback: (11)

Remember something, pcm may lessen glitches but a problem is a problem and usually on a nitro heli, you can sort out whats going on. Gas ignition systems are another story.

Take all your connectors out of the reciever and disconnect everything (1 at a time or whatever) and put it all back together. This will clean any minor corrosion from the connectors. Take a good look at the tail and gyro related stuff and see if there's any fuel or residue on the connectors. If there is clean everything with alcohol or spray contact cleaner from Radio Shack and put it back together. Heat shrink the battery to switch connection and the stuff going back to the gyro and tail servo.

Look for any metal to metal contact like did you use a metal clevis on the throttle arm, a glow extension chaffed and rubbing against a motor mount, stuff like that. Also pay attention to your wire routing versus antenna routing, keep the antenna away from as much stuff as you can.

Are you using a wire antenna or some sort of whip?

polygoo

i've got the antenna wire which is fed into a nylon tube and is parallel to the heli's body.

I've looked over everything once more, and the only thing I can think of is that my tail rudder control rod is a little close the the tail boom, which, in certain scenarios, might be touching the side of the boom causing the twitch. I guess I'll have to figure out another way to mount it, although I went ahead and got a PCM reciever for my 7c anyway so i'll hope for the best.

I also got a frequency checker so i'll know its alright to fly (at least fairly alright) lol

heli-john

Had a twitch like that on a Shuttle I once had and found a tail boom stay broken at the crimped end but still holding. Took a while to spot and had been causing a radio glitch.

rusirius

You had just increased collective/throttle when that happened right? Definately looks like a mixture problem. From the sounds of things, try backing the low-end needle out about 1/4 turn. May even take 1/2, but try 1/4 first....

polygoo

well I think I figured it out. First I ran out and bought a frequency checker and scanned the area for my channel, and found that there was intermittent signals on my channel in that area, it would come and go... however the helicopter would not twitch at all (on PPM setup) from the interference, so I figured they were either stray signals coming from somwhere or something to do with the enviroment. With the antenna off of the hobbico frequency checker, I noticed it would not pick up the signals on my channel, that tells me that its a fairly weak signal.

So, knowing this I went out and bought a PCM setup and have had no problems ever since, i've been checking every time before and during I fly, and usually there is no signals on my channel, but sometimes there is and I dont fly that day. I'm not sure if the glitching was coming from something nearby on my channel on that specific day or what, but now with the PCM and frequency checker, I am no longer having any problems.

Next I have my eyes set on getting a 9C PCM with the synthesizer setup, I've been scanning the entire area where I fly all the time and have found nobody on any other channels, so I am thinking of switching to a different channel, plus with the synth, I can switch on the fly if I find someone on my channel that day, which is really nice.


I am just hoping I can use the 9c with my blade cp as well because I hate the radio that comes with the blade.

heli-cuzz

Hey pg, I just checked your glitch vid. I believe you need to lean up your midrange. I had the same problem and finally got my engine tuned correctly for the most part. It seems when the head speed rpm's are too low the heli bounces around. Your engine should run rough for a minute while in a hover, then it should clean out and start screaming. Proper head speed means much better control, stability, and lift.

Oh yeah, I doubt your super 9 will work with the cp blade, I already tried, mine didn't.

-pkh-

My Feedback: (2)

You just need a single conversion Futaba crystal for the Blade's receiver to match you 9C TX frequency.

Check http://www.runryder.com ... there's a thread on using the 9C with the Blade there... they have some eCCPM setttings for it too. I got an xtal to match my 9C... haven't tried it yet myself... been doing OK with the stock TX so far so I haven't had the urge to mess with it yet!

polygoo

well what I ended up doing was getting the 9c super with synth, and I changed my channel to a different one and havn't glitched ever since, I hope its gone for good!

I actually got my 9c setup with my blade no problem, I matched the channel with the module, and read thru some other posts on setup starting points and it took a little while to get it setup right but its actually flying pretty well now.

-pkh-

My Feedback: (2)

You got the synth module for the 9C, eh? I'm jealous... I need to get me one of those...

polygoo

lol, this thing is amazing, I absolutely love it, I can adapt it to any plane or heli I own on the turn of a screw... awesome. i wish they made this for every radio.

heli-cuzz

it's such a beautiful thing.... ain't it?

I have the same one, I feel a beginner would benefit from this radio far more than a cheapy six channel like my first heli-radio.

credence

My Feedback: (2)

I'm using a synth module on my Eclipse 7. It's the greatest thing since sliced bread .

The only thing I wish they could do is memorize different frequencies for different model settings. It's sort of a pain to have to switch the knobs when going between different models. Not as big as a pain as switching between crystals, but still..

polygoo

I know, I thought the same thing! I wish it was all digital, and you could change the channel without turning a screw.. but I guess thats just being picky.

-pkh-

My Feedback: (2)

If you're flying by yourself, that would be great, but if you're at a field, you're likely to forget to get the right freq pin for the model... at least if you have to power off and turn some pots to retune, you're more likely to think about getting the new freq pin...

heli-cuzz

What, and you want somebody else to fly it too. LoL

j/k