armody

My Feedback: (10)

Correct me if I'm wrong, potentiometer keeps the gimbals straight? or is electronic circuit? if it's bad how do you check it whether it's bad or good? If it's bad, do I have to buy it and replace it myself?


Mody

hsukaria

The glitches I was having were quite severe. Not just small twitches, this was the rudder going hardover beyond the normal range of operation, and the throttle going to open. And the was the same for the field and home. So, hard to explain why. But Futaba replaced the antenna and a bad potentiometer on my 6EXAP transmitter. I hope that solved it. I'll find out soon whenever the weather cooperates.

hsukaria

I don't know which potentiometer it was that Futaba changed, but it wasn't something I know how to troubleshoot without full circuit drawings and specs. But it might explain the shorting between the rudder and throttle I was getting. I hope that was all. The receivers, both the Hitec Supreme II and the Futaba R168D Rxs checked out good by their manufacturers.

I got some glitching on the U Can Do 46 as well (in the field and home), that is how I started to suspect the transmitter.

opjose

Yes that is what is being asked. Your setup permits the generation of RF via the "Z" bend to motor contact and the linkage rod.

We normally try to avoid having metal linkages touch the engine, or the throttle for that reason.

This could be another, or THE cause of your problems.

armody

My Feedback: (10)

hsukaria,

Yeah, I experienced the abnormal movement in rudder and elevator like they were shivering out of cold, I have never seen a whole plane jolted or fluttered or shook up in the air but it did. I'm using the same radio only it had 2 model memory, Finally today got a job offer, starting out on April 30th though again project is for 2 or more months but something is coming in. So I was same I'm using same TX with my Mustang PTS and RX is Hitec's Electron 6 no problem at all. I guess escapade is not a good plane for me. There is another guy at our field, his escapade is still stuck up into the branches of the tall tree.

My Tx is outta warranty, I may goto 2.4 Ghz but a lot of people get their radio locked out and plane crashed, I did not get answer to that, infact this thread is not about 2.4 Ghz, but what is the answer to the radio lock out on people and that had caused people crash their turbines so where do we stand, and what choice do we have, where there are great risks exposed all the time.

Mody

JohnBuckner

My Feedback: (1)

Forget the servo end, If the pushrod had a z bend to attach to the the carburators throttle arm and that arm is metal i,e, metal to metal.

Then it highly probable that this is what killed your airplane.

In the so called good old days all systems were AM and were very prone to interferance from the metal to metal contact at the throttle arm and everyone soon learned not to do that and use a plastic clevis.

Then along came FM(PPM) systems and these were far better however they would still be
affected by this interfearence when the hole wore and the frequency of the RF noise reached
just the right point and bang yet another unexplaned loss usually attributed to something else.

I frequently see folks who isist on using metal to metal experiance some uexplained loss down the line somewhere.

When someone asks me to maiden an airplane with metal to metal throttle arm and it uses a 72 system I won,t do it untill its corrected.


John

armody

My Feedback: (10)

Servo end forgotten. I never knew that metal to metal specially Z band would make my plane to goto ZZZZZZZZ and crashed. I'd never and ever do that to any other plane. I have noted this advised and holding on to it tight.

Thanks and thank you all very very much for your great output.

Mody

aramsdell

I just scanned through the thread really quick.. Maybe I missed it but it really sounded like his first problem was aerodynamic flutter. Has that been ruled Out??

Armody, If you haven't ruled out aerodynamic flutter as Part of the problem then you should. Check that the rudder and elevator linkages are TIGHT.No slop. If you have slop ther surface can start osscilating back and forth in the air. Sometimes so violently that the surface is ripped from the plane. I have actually had this happen on the bench. A cheap digital servo for my rudder on 72" YAK as soon as the rudder was moved and the stick release the rudder shook back-and-forth violently. There was some slop in the system from using Pull-Pull cable on the rudder. THe same will happen if the servo is sloppey or the hinges or the control horns/clevises etc show slop.

hsukaria

I will now go and check and redo any throttle pushrod that is metal-to-metal also. But I know that some engines now have plastic throttle arms, so I assume that is ok to have a Z-bend on those.

As far as flutter, especially for planes with big control surfaces like 3D planes, I make sure I put the pushrod on the outermost hole on the control horns of the servos and surface. That helps to reduce/eliminate flutter as well as keeping the linkages tight.

jester_s1

Another very common culprit in glitches is the batteries. If you batteries are over a year old, you should cycle both the TX and RX ones and load test them to be sure they are doing their part.

armody

My Feedback: (10)

aramsdell> Clevises and linkages it's a good point but the plane was ARF and I made it and I made sure over and over again that all the linkages were correct. There was nothing wrong with 'em. Aerodynamic flutter, I don't think it had got to do with linkages or air, wind was most likely 8 to the far extent 12 Mph. So I have ruled out aerodynamic fluttering.

jester_s1-> The battery back is brand new. It is spectrum's 1500 nimh, I got it with my Mustang so it's new.

I'm gonna know next week about receiver from the tech department of Hitec.

No Zzzzzzzz bands, no metal to metal. Lesson learned. Many things I learned.

Mody

hsukaria

Batteries for 2.4GHz are even more critical because of brownouts causing them to reset. That is not the topic of this thread, but the originator mentioned problems regarding that. I know many use 2 batteries for safety purposes. I heard that some of the newer systems are less prone to this by having Rx's that work to lower battery voltage levels, like the Hitec Aurora 9.

tony0707

HI NEED to keep your antenna -AWAY FROM ALL OTHER WIRING IN THE FUSEjust had the same problem and i know better or i should know better after 20 years of this stuff

opjose

While I agree that it is unlikely to be flutter, from the above it sounds as if your assigning the blame for flutter to winds.

Flutter is caused by an unwanted but very rapid oscillation in a control surface. The plane may fly almost normally when this happens.

USUALLY flutter is caused by flying the plane TOO fast and/or with a sloppy linkage and/or weak servo setup.

-

Running the antenna wire close to other wiring is a good candidate for the cause of your problems...

as are

- Weak battery voltage ( you've ruled it out ).
- Metal to Metal contact with the motor ( which you've ruled out ).
- Other spurious RF noise ( Jury is still out on this.. Does ANYONE EVER successfuly fly the channel you had your TX/RX on at your field? )
- Loose Crystal in the RX or TX ( this may not be obvious ).
- Loose connector, switch or other intermittent short or connection..

While you may indeed simply have a bad RX, unless it has been in a prior crash or abused by someone else, the likelyhood of this is relatively low, which is why everyone is coming up with other ideas...

armody

My Feedback: (10)

opjose,

Metal to metal I have not ruled out, yes, as you mentioned so that might have been a good cause of it, yes, wind I ruled out, it all happened so quick, I didnt have time to blink my eye and here plane goes down on the ground. As far as control surfaces fluttering is concerned, it was not due to loose likages, thats for sure, battery voltage yes, it was perfectly charged, so i rule out battery prob, as it was brand new never used. I don't accept anything which I don't agree in a sense that I was asked questions and I gave the answers of all, that what might have caused the probs, many things have been ruled out cos they were not that way which one may think about. Crystal I saw it was fully seated all the way inside, so Xtal was intact.

Causes of crash,

Antenna wire attached to servo,
Metal to metal throttle arm linkage
Receiver malfunction

As far as Receiver is concerned, it was in the box, again yeah anybody can put any receiver in the box, Rx did have a scratch on the front side, I did buy it off of ebay, that guy has his rc store on ebay, have a lot of stuff, as far as abuse is concerned it could have been prior, who knows, he ripped me off by selling me bad batch or used one or Abused
one as per your statement which can be true how would I know I got right receiver did not buy physically from the shop. Final verdict would come out once Hitec's tech department tells me something next week. I'd keep you all apprised.

Mody

armody

My Feedback: (10)

Nobody flies on my channel which is 51, Linkages and connectors were good, and plane did fly with fluttering and yes controlled surface oscillated while plane was sitting on the top of the testing bench, rudder and elevator fluttered on the ground and up in the air. I have said that many times, agreed to those things which might have been the problem, but in my previous statement a while ago I said, last verdict is receiver which would be given by techs at hitec, otherwise what you guys have suggested the reasons, like antenna wire attached to the servo and metal to metal, these are the most like cause of the crash.

MetallicaJunkie

mine worked good for a while with my JR10x till my wing snapped mid flight...., i used it on primarily small glow stuff. i liked that it had auto phase shift so that it could be used on futaba and jr transmitters

rcjetflyer0718-RCU

My Feedback: (1)

you can get into a 2.4 radio for $60 from Hobby People more capable than your JR 421. Just go back to your threads from a month or 2 ago. So instead of wasting your little bit of money on used cr*p off ebay buy something that you can send back if it doesn't work.

armody

My Feedback: (10)

This Hitec's Supreme IIS is dual conversion. I'm waiting on the words from tech department of hitec. That'd the final verdict

Mody

hsukaria

I agree with rcjetflyer. If all you have so far is 1 transmitter with 2 receivers, and one of them is going back to the shop for repair with added cost, it makes sense to jump to 2.4G with great deals going on. I know that Hitec is having their 6 ch 2.4G Rxs for $50 each. Check Tower Hobbies for bundle deals. As mentioned, Hobby People has super deals on Airtronics radios too. Both great systems.

Mr Cox

My guess is that there is nothing wrong with the RX (Hitec may simply replace it anyway), the throttle connection is the bad one here.
Gitter already on the bench as soon as the engine is running, sounds exactly like a throttle linkage interference.

No need to change radio just because of that, both systems have their pros and cons.

jester_s1

It may not be the cause of this particular problem, but your battery practice still could use some work. I don't ever fly without verifying a new battery pack on the cycler. That saved a plane once, as I had a bad pack from a reputable manufacturer straight out of the package. Your transmitter battery is also suspect. I got an intermittent glitch once early in my hobby experience, and found that the TX battery had gone bad. From those experiences, I bought a used Triton charger and now cycle my batteries every other month and check the flight packs with a load before every flight. Doing that, I will catch a pack fading long before it can cause a problem in the air.

With the 2.4 battery issue, only early Specktrum systems had the lockout problem. The RX would reboot below 4 volts which took about 5 seconds. So people using a marginal pack would get hit where a 72mhz system might not have a problem at all. Spectrum has since redesigned their recievers to reboot in about a second, and everyone else's will work at lower voltages than will ever be encountered in a properly working system.

armody

My Feedback: (10)

I appreciate all of yours great feedbacks. Since July 2009,. I had no consistent/constant/permanent job, I'd been working on and off. May God Bless USA as ecomony has started moving little bit up, I got a job which I'm starting off on 30th April, it may be more than 2 months then it may be extended or not, but not sure, so something is better than nothing.

Moving up to 2.4Ghz is very easy with the money, and it's not easy for me like other people. I gotta go with my pocket,. as it's not easy for me to afford anything at the moment, as my unemployment is also stopped. I have seen many videos of 2.4Ghz gets locked out, so 2.4 Ghz is as vulnerable as 72 Mhz. I have seen videos people flying turbines on 2.4 Ghz, and radio locked out, and here the plane crashes, after being crashed they have their signals back but too late. I guess FM has it's on pros and cons, so does 2.4 Ghz.

I'm gonna go to 2.4 Ghz after getting back on my feet good, and after careful and good consideration. In the meantime I'm gonna adhere to those which I'm using.

Thanks again you all

Mody

hsukaria

Good luck with the job Mody. I just went through a tough year too. I got a good permanent job just 3 weeks ago and things are looking better from what I see.

Meanwhile, enjoy flying. It kept me sane through it all.

Gray Beard

My Feedback: (-1)

It just now hit me like a brick while I was reading the latest posts. I haven't run into any bad RXs out of the box new but I know it does happen. What did happen to me was one of my planes started having controls going in all directions?? It was an older plane, not new but I don't ever have too many problems with my stuff. I got it home and started going through it to see if by chance I didn't have a servo problem or some other electrical problem. I turned on the plane and the controls were kicking around like yours, I pulled out connections one at a time with no change. Then I pulled the switch wire and plugged in the battery directly into the RX, SHAZAM!!!!! No glitches. I plugged the battery back into the switch and plugged the switch back into the RX and the plane went nuts again. This was a good JR heavy duty switch with the charge jack. I replaced it and all is well again. I used electrical cleaner in the spray can and cleaned out the switch and it started working again. I did toss it due to lack of trust but I thought I should mention it before the memory flies out of my gray mater!! My controls would bounce around with or without the engine running too. How is that guys, a mind like a steel vault!!!!