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JR G410T Gyro and Radio Interference

dkshema

rrMaster

Cedar Rapids, IA

Hello, I'm new to the RunRyder forum...to the point.

I have two new JR G410T gyros, one installed in a Kyosho Caliber 30, the other in a new JR Venture 30CP.

The radios are the same, a JR 662 TX, and R700 receivers and 537 servos. (Although I've also seen my problem in an R600/537 combo, and R700/517 combo).

As long as either gyro is installed in the system, the receiver is unstable and the servos hunt all over the place (similar to days gone by when it was easy to swamp out the receiver front-end).

My Caliber 30 is totally unflyable with this gyro, the Venture bought the farm a few weeks back to due to a nasty radio glitch.

It is my opinion that the gyro is either putting trash onto the power/signal lines, or that it is radiating RF energy that is interfering with the RX front end.

Horizon has graciously (?) offerred to "upgrade" me to new JR G460T gyros if I send them the 410s and an additional $40.

Has anyone else seen this problem using this gyro?

Is the 460 better, doesn't have this problem?

Is there a known problem in the 410 that replacing with a 460 will fix?

Will I be spending an additional $40 and still have the same problem?

Should I pitch the 410s and go with a Futaba gyro?

Thanks

Dave

08-07-2002 Over year old.
Gearhead

rrMaster

Vt

410 /460 ???

Dave,,, dude,,, I had a JR 410 and I thought it was a great little gyro, or until that heli's first hard landing, then it would not work, all the servos jumped around, up till that one landing it worked great, it held the heli straight in wind even with the HH off !!,,, as I know the 410 and 460 are the same gyro, but the 460 has an extra wire that plugs into your Rx so you can adjust the 460 on your Tx,,, if you don't have the extra channel on your Tx you don't need the 460, so if you don't have that extra channel you don't need to spend the extra cash,,, this is what I would do, I would send them back and tell them to send 1 410 and 1 460, if you radio is a 6th channel then get 2 460s if you can afford it,,, sorry I don't know how many channels your Tx has !,,, JR replaced my 410, I'm going to use it on a small scale heli, just turn on the HH and fly !!

Jim

08-07-2002 Over year old.
dkshema

rrMaster

Cedar Rapids, IA

Thanks -- my radio is a 6 channel, so of course I can use the extra channel for the gyro.

I'm more worried about the fact that both gyros drive the radio nuts...and don't want to pay another $40 just to find out I still have the basic problem of the gyro making the RX useless.

I'll see if anyone else replies...and go from there. Thanks again.

08-07-2002 Over year old.
Jack_R30

Senior Heliman

MY

Go for GY401

Jim,

I have JR410T and my friend have JR460T, I can say it is a cheap and great gyro for budget / beginner flyer but it will fail eazily cause by vibration. Please be carefull with this gyro. It will fail during airborne. (I have REALLY good experience with this gyro )

Both of us changed to Futaba 401, the hold power is amazing compare to JR401T and JR460T!!

I would say, go for Futaba GY401/S9253 combo. You will LOVE IT.

Just some advice .


Jack

08-07-2002 Over year old.
Gearhead

rrMaster

Vt

401, yeea

I have a 401 on my Falcon, I like it,,, as for the 410 I did (did) want it for a Century Bell 47g, maybe I'll sell it !!

Jim

08-07-2002 Over year old.
mike lewis

Senior Heliman

northeastern AZ

gyros !

Hello from northeastern AZ I would B more inclined to look at reciever position and ant location as the reason that it appears that the gyros are causing you a problem I fly with the 410, 460 & CSM Helis and planes with helis the close positioning of all componets will make it very sensitive to each other. The condition of the contacts, in the off on switch, the good connections of all plugs and battery problems are many many times the problems we blame on the gyros. I am not saying that you don,t have a bad gyro but I find so many times it is other than gyro. Jr product [G410t & G460T ] have been the best money I have ever spent on my planes and helis Last of all consider the servos that you use with the G410t &G460t you can't beat a basic set up that uses standard to mid range servos $8.00 to $80.00 very wide use band so invest in the G460t if you want it is not a bad up grade price and it will be sure to please you untill you enter your no fear of wasting your heli aerobatics attempts that come a little later on. God bless and keep your rotor spinning Mike

08-07-2002 Over year old.
GMPheli

Elite Veteran

W. Bridgewater, MA USA

I got a used JR G400 gyro from my buddy. I didn't use it because I had the same interference problem as you with my PPM receiver. My buddy was using it with PCM and it worked fine. BTW, I tried it with 2 different PPM receivers. I think this series of gyros generates noise.

Alan Angus

08-07-2002 Over year old.
dkshema

rrMaster

Cedar Rapids, IA

A bit of a follow up. I've spent the extra $40, got two new G460T gyros from Horizon, and still have the same problem. Experiments have shown that these gyros essentially make an R600, two R700, and one older NER-627G PCM receiver. I've shown that as long as the gyro is plugged into the RX, the RX cannot be depended on to keep a solid RF link with the transmitter.

I've also built a short adapter cable with three 10 microhenry chokes in it -- one in series with the power, ground and signal wire. It plugs between the Rudder output of the RX, and the gyro. This did not help the R600 or R700 performance, but appears to have made the NER 627G PCM RX happy (at least is doesn't appear to respond to signal dropouts now). I believe the R600/R700 receivers share the same RF front-end design. The NER 627 G PCM RX may also share the same design, however it was also designed at least nine years ago, so it may have a different heritage.

In the meantime, I have ordered a HITEC/RCD 8 channel dual-conversion FM receiver to see how it performs. All the JR RXs are single conversion, the dual conversion may help with this problem.

I'm doing further investigation, and hope soon to have a definitive answer. As it is, I've had my Caliber 30 ready to fly for over a month, and haven't gotten it off the ground due to this problem.

Maybe it's time to switch to Futaba...

08-20-2002 Over year old.
Gearhead

rrMaster

Vt

Tell us if the new receiver works !!

dkshema

I have a new (3 weeks old) HITEC/RCD 3600 8 channel dual-conversion FM receiver, and I swear it's a better receiver than my JR NER-549, my servos are now quiet when they are at their neutrals !!

Let us know !!
Jim

08-20-2002 Over year old.
Skywalker

Heliman

West Kentucky

Same Problem

I had the same problem with my 410t. When I got the gyro NIB, my servos twitched and jumped and I got regular hits once airborne. I sent the gyro in for repair, and Horizon replaced it with a NIB unit at no charge. When I re-installed it...PERFECT. No servo twitching, no more hits etc.

A couple of months ago I had a nasty boom strike. I rebuilt the machine and on its maiden test hop, the tail was totally out of control. I landed safely and removed the gyro. To my astonishment, there where loose parts rolling arround inside!! Horizon "repaired" (cost me $40 this time). I re-intalled, but the servos where twitching and such. I finally decided to ditch this gyro and buy a 401.

I was VERY happy with the gyro when it worked. I believe this is a good gyro, but VERY FRAGILE. With the new lower price of the 401, the 410t looks like a rip-off.

Michael

08-21-2002 Over year old.
dkshema

rrMaster

Cedar Rapids, IA

My new Hitec/RCD receiver arrived in the mail at noon today. Tonight I'll be installing it in the Caliber. Should have some initial data later on. Ca't get out and fly it until this weekend, though, it if works on the bench.

08-21-2002 Over year old.
dkshema

rrMaster

Cedar Rapids, IA

Bad news. The Hitec/RCD 3600 Supreme 8 channel receiver was a total disaster when operated in my setup with the JR G460T gyro. To date, I've had my Caliber 30 for about seven weeks, and have been unable to even get it off my workbench to fly. I've tried a JR G410T gyro, upgraded via Horizon to a JR G460T for an additional cost, and as long as either JR gyro is installed in the radio system, the receiver is unstable and the radio unflyable.

I've tried two different JR R700 FM receivers, a JR R600 FM receiver, a JR NER-627G PCM receiver, and now the Hitec/RCD dual conversion FM receiver. None of these radios is usable in my system as long as the JR gyro is installed.

I'm preparing to write a nasty gram to Horizon, then switch to Futaba gyros. I may have purchased my last JR product ever.

08-22-2002 Over year old.
Blackdog

Senior Heliman

In a snow bank.........with no money

Slow tail servo??

I'm using the 410 gyro on my R30 with a futaba 9402 servo. No problems. Do you think the gyro is not working right because the servo you have hooked up to it is to slow?? Just a guess. Because you have tryed different recievers with the same result. Alot of times when I hear people having problems with their gyro's it's because the servo that is hooked up to it is too slow.

One other thought, do you have the gyro plugged into the right channel on the reciever?? I'm not at home right now so I can't tell you which channel is correct. I'm using the same set up. JR 652tx, R700rx, and 410t gyro. Let me know how you make out. Maybe I can try different things on my setup and let you know the result.

One more thought, how's your gain setup? In the instructions they show you a picture of the gain knob and the postion it should be at. What I did was set the gain dial like the picture shows which is like and X. Then yawed the heli and watch the tail servo. You want a little movement from the servo not alot.
Blackdog

Addicted to Kaos and destin for disaster

08-22-2002 Over year old.
RC-CAM

Senior Heliman

USA

A couple of years ago I helped a guy with gyro related interference. His servos would just go nuts. He installed a ferrite donut core on the gyro's wire harness and the problem was instantly gone. I do not recall what gyro he was using, but I believe it was a JR.

But before I offer the details to this fix, I have a few questions (to ensure it will not waste your time).

(1) Is your gyro or its servo using an extension? If so, what segment is it on? How long is it?

(2) How much excess wire (in inches) is available between the Rx and gyro ? Between the gyro and servo?

(3) What are you doing with ALL the excess servo wire? How is it coiled?

(4) Is your pack a 4-cell (4.8V) or 5-cell (6.0V).

(5) Is the T/R servo boom mounted?


08-22-2002 Over year old.
HOMEPAGE  
dkshema

rrMaster

Cedar Rapids, IA

Thanks for the thoughts -- but I've pretty much determined that the root cause of the problem is poor (inadequate) design of the G410T and G460T piezo gyro when it comes to controlling conducted and radiated EMI/RFI.

This isn't a question of the servo speed, or which receiver channel the gyro is plugged into, it is simply in my opinion, a design flaw in this series of gyros. Frankly, which channel of the receiver the gyro is plugged into is of no consequence, other than the wrong control function would be slaved to the gyro amplifier. Servo speed is also not a factor, as at this point, the heli is sitting on the ground, no engine running, and only the transmitter and receiver turned on. I'm not even trying to have the gyro stabilize the yaw axis, I'm simply trying to have the radio remain quiet and the servos maintain a static position with the heli sitting on the ground and not running.

I've crashed a new Venture 30 with one of these gyros as the heli, from a hover about two feet off the ground, and ten feet in front of me, shot straight up about five feet, and then immediately straight back down into the ground with no warning or time for me to do anything about it.

Having gone through a total of seven different receivers -- FM, PCM, and dual-conversion FM, all with similar RF problems, and with additional tests on my workbench, I've concluded that the problem is a design flaw in the piezo gyro.

I've detailed my problems and experiments to the Horizon Service Center, and have simply asked that I be able to return their G460Ts and they refund the $300 I've sunk into them. Hope they take me up on the offer.

What is really spooky is the thought of all those JR piezo gyros of similar design flying around the skies -- and the consequences of glitch-induced crashes and the economic and personal risk that could come to this sport.

I've been an avionics design engineer for over 18 years, and have flown RC models since the single channel tone transmitter, super-regen receiver, and rubber-band powered escapement days. My first heli was the DuBro Whirlybird 505 chopper. In all those years, I have never experienced a problem of this magnitude or depth in the RC realm.

08-22-2002 Over year old.
GMPheli

Elite Veteran

W. Bridgewater, MA USA

Hi Mr. RC-CAM:

On my installation, I had a boom mounted servo, and I tried the gyro mounted at both the front, and rear. I would get intermittent glitching with the engine not running. When rear mounted, I did not use a servo extension, but the supplied input wire is quite long. I believe I folded it back on itself to shorten it. When front mounted, I shortened the input wire, and lengthened the output so they were just the right length. I would guess that the length between the gyro and servo was about 18 inches. I tried regulated 6 volts, and 4.8. I started getting this glitching upon installation of the gyro, and it stopped as soon as it was removed. I tried 2 different receivers, a Futaba 127 DF, and an Airtronics FM, I forget the #. I would assume you would install the ferrite bead on the input as close to the receiver as possible. How many turns would you recommend?

P.S. I do not understand what the "segment" is in this question.
"(Is your gyro or its servo using an extension? If so, what segment is it on? How long is it?"

Thanks
Alan Angus

08-23-2002 Over year old.
tvoydan

Senior Heliman

Metro Detroit, Michigan

Its the gyro/servo combo

A guy in our club had the same problem with this gyro. After alot of experimentation, we finaly concluded it was the gyro. I also had similar problem with the JR 550 gyro.

See my posts:

http://www.runryder.com/showtopic.h...9&topicid=19207

I spent several weeks of down time mucking with my 550 gyro and my friend spent about 2 weekends with his 460 trying to resolve this problem.

The Futaba 401/9253 combo is hard to beat for price. But I have been hearing that some of the 9253 servos are going bad.......hmmmm


08-24-2002 Over year old.
HOMEPAGE  
dkshema

rrMaster

Cedar Rapids, IA

Thanks for the info. I hope to get a lot more anecdotal evidence about the fine JR gyros.

Airplanes and helis are getting more and more sophisticated (read that as "expensive") and pilots are pushing them to their design limits. There is no excuse for radio manufacturers to continue to cut corners in their designs. I believe there are a lot of flyers out there who are experiencing glitches from poorly designed gyros that emit RF and electromagnetic radiation that puts the RF link between the TX and RX at risk.

A solid radio is a must, gone are the days when a flyer expected to put up with less than reliable radio equipment.

The cost of a good radio system is going back up. A few years ago, not many people would be willing to pop a $1000 for a radio system. Nowadays, it is not unusual for a heli radio to sell for $500 to $1200.

With radios going for that much money, I would expect design for EMI/RFIcontrol to be an integral part of the system. To buy a $150 gyro that puts your entire system at risk because its design is missing a few inexpensive ferrite beads, shielding, etc, is crazy.

I believe it is time that we consumers begin demanding more for our money -- not more chrome plate and jazzy looking switches and front panels, or LCD screens on our transmitters, but for more reliable, bullet proof radio links.

08-24-2002 Over year old.
KevinBourland

Senior Heliman

Springfield, Illinois

This topic saddens me! I have had faith in J.R for years, (with planes...cars..boats...)so I bought an Ergo-30. I put in a cheap Revolution gyro 517 servo's and it works great! Maybe not 3d....but it handles great and has been reliable !
I then bought a Venture, put "The New" Ds811's all around, a new 9 channel Ner549x receiver/ and what I thought would be an awesome Gyro"The G550t" and what do I have? A heli with all J.R. stuff which is making a nice paperweight due to the glitching with all servo's that I get from hooking up a DS811 servo to the tail. I am puzzled. I am not going to put magnets around my servo leads..." we" should not have too! I bought all items becouse according to the Info from J.R they should all work together as one big happy family! Servo extension? They know that we need them longer, so why not make Heli servo's with either a short lead or a long lead ?
After reading these posts, I really don't know what H.H. J.R. gyro to get! It's almost scary!
"Frustated Paperweight owner"
Kevin

08-26-2002 Over year old.
HOMEPAGE  
tvoydan

Senior Heliman

Metro Detroit, Michigan

Been there, done that

Get the Futaba 401/9253. For under $200, it just can't be beat. Period. I've been thru this all before with my JR gyro....

My experience says that the JR pilots I know who seem to have NO problems are running JR's high-end equipement.

I seriously recommend sending the gyro/servo back to JR or contacting them. They may have a solution.

I have two 550 paper weights right now. I'm pretty much done with JR electronics.

P.S. I have not been hearing good things about the Venture. But the Ergo is a great machine. I hear nothing but praise about it....


08-26-2002 Over year old.
HOMEPAGE  
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JR G410T Gyro and Radio Interference

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