RK-Aircraft

My Feedback: (81)

I just converted my H9 Ultra Stick Lite120 to electric. It's fit out like this: APC 16x10 electric prop on an Actro 40-4 brushless outrunner, JETI 77 controller, TANEC 9s2p 4400mah Lipos, Hitec Electron6 rx on a Deans "JetJock" antenna w/6v/1300mah NiMh bat. on switch harness, Hitec 645MG servos all around. Other mods include a TT trainer cowl from Stans FiberTech to protect the motor from dust and debris, CF landing gear from GraphTechRC.com, Dave Brown lite 4" wheels. I also opened a hole in the underside of what used to be the fuel tank compartment behind the fire wall. I used a plastic scoop and cut off the spade and glued it under the hole to drive air into the battery compartment. Well, the damn thing is faster than a jet and vertical is unlimited out-of-sight in a high rates, full throw roll. This thing is a fire breathing dragon that will out run ANY stick on glow power thats out there.

I give you all these details to determine what is causing a glitch in the electronics that is causing the control surfaces to twitch in flight. I did a range check and went out about 50 feet and it was OK. 100 feet and the motor started full throttle, the control surfaces went nuts and the Stick spiraled around until it nosed down and stripped off the blades. Need less to say that the Stick is in the hangar and grounded until further notice.
I checked: no metal to metal contact, no metal washers on screws, no loose connections, the ESC is over 15" away from the rx., etc. This would not explain the motor start. (no vibration to cause movement).
Could the metal gears in the servos be at fault? Faulty ESC? The JETI does not use a BEC so the rx is on a separate battery. Anyones thoughts are welcome....

airflow

My Feedback: (1)

I'm new at this game, so consider this a question and not an answer to your problem. If you have a separate supply to the receiver, either from a BEC or a battery, and not from the ESC, don't you have to disable the positive pin going to the receiver, usually the Throttle input, from the ESC ?

RK-Aircraft

My Feedback: (81)

Never heard of that. The lead from the ESC to the rx has the conventional 3 pins @ channel 3. The battery is fed at Channel 5.

gwh

The Jeti 77 is an Opto controller and does not have a built in BEC. This ESC must get its power from a external source such as a Rx battery, UBEC, or regulator. You would never pull the positive pin on this ESC. However many BEC equiped ESCs do require the positive pin to be removed when using an external power source.

Did the problem go away when you pulled the antenna out during the range check?

Was the in air twitching in the same place in the sky each time?

Was the twitching limited to any specific control surface(s)?

Do you have another Rx to try in the plane?

Can you perform another range check, without a propeller,
check with one set of servos at a time if necessary to try to isolate where your problem is coming from.

Since the plane acted up on the ground without the motor running I doubt that the problem is from metal to metal contact.

d_wheel

On one of my installations I had a similar problem. After adding a filter between the reciever and esc my range checks went back to normal and there is no more glitching in the air. This is the one I used:

http://www2.towerhobbies.com/cgi-bin...?&I=LXDKP6&P=7

I now always remove the prop (unless someone is holding the model) when doing range checks.

Later;

D.W.

RK-Aircraft

My Feedback: (81)

All good questions, GWH. This is the 2nd receiver I'm using. I flew once in two different fields thinking that I was getting outside interference. In both cases it would appear that it wanted to roll. The 2nd time it went inverted. I have aileron and flaps on my set up. I'd hate to think I have bad servos. They're not cheap. But it still doesn't explain the motor launch.

RK-Aircraft

My Feedback: (81)

Thanks Dwheel. It can't hurt.

airflow

My Feedback: (1)

GWH - Thanks for clearing that up.

paraglidesam

Go to your loca radio shack store, ask for an RF choke. They should hjave one that is a little rectangular box shaped one part number Catalog # 273-105. Try this on the lead from the speed controller (escapement) to the reciever. My trex wasw glitching until I added this device,,, now i'm REALLY HAPPY!!! No more glitching,, which by the way, on a Heli, is REALLY BAD!!!

RK-Aircraft

My Feedback: (81)

Thanks, Sam.

RK-Aircraft

My Feedback: (81)

Hold on folks. I found the answer to one of the two problems. I am running a 6v battery in the stick. I jsut found out that Hitec 645MG servos don't like 6v. Something about RF noise. So!!! I'm gonna put a 4.8v in and run a test. I also got a test to run from Hobby Lobby to determine if my ESC is faulty and starting my motor full throttle without TX input.

More later,

George

paraglidesam

Don't wanna bust yer bubble, but i use a LOT of Hitec 645 MG servos in my 120 size airframes,,, Dave Pastrick Ultimate bipe, hangar nine edge 540, ultrastik lite 120, and World Models Cap 232 all with 180 Saito nitro motors on them, and ALL of these aircraft use five cell nicad packs delivering 6 volts...I have not had ANY jitters on these, but none of them are electric,,, I only mentioned the glitching, as I was having this problem REALLY bad on a little trex chopper,,, Installed the radio shack part,, and now,,, thankfully,,, it dissapeared,,, Hope you get 'er flying reliably,,, That is ONE of the main reasons I really like e-power,,, I havent had a SINGLE DEAD STICK with the foamys, or the trex ,,,(yet!)

RK-Aircraft

My Feedback: (81)

Sam,
I was also told that a servo filter does the same thing. http://www2.towerhobbies.com/cgi-bin...?&I=LXDKP6&P=7. I'm also going to send the JETI in to be checked out.

paraglidesam

Ahh yes,, I see the ferrite bead rf choke in the wire there with the servo lead repeatedly looped thru it... Will probably work fine, It.s just theat the one at Radio Shack is about $5.00. I'm pretty sure that if you put this extension in line it should stop the jitters.. I'm too new at electric power to know if youy need to put one ie each servo wire that is jittering, or just what. Noise from my speed controller was the culprit in my case, and I only needed to put one choke on that particular wire to stop ALL my little glitching...Just wondered too,,, HOw does that stik fly with E-power as you have it set up,,,I was thinking of doing the World MOdels Cap 232 electric, as it is one of the 120 size planes the seems to fly quite well on only a 120 four stroke, but kinda gun shy on the $$ of the larger electrics!!

RK-Aircraft

My Feedback: (81)

Well, it's hard to evaluate how it flies because its only flown twice for 2 mins ea. Each time a serious case of the jitters, so I landed right away. Its seems that when I cut the throttle to dead stop, the jitters go away. This also leads me to believe it's the speed control. But when it was in air, I got unlimited vertical power and tracked straight as an arrow. I have too much lift at full throttle which tells me I need more down thrust. I compensate with a little down trim. The Actro 40-4 is a beast. It blew my wall cabinet doors open when I was testing it in my work shop at 3/4 throttle!!!

gwh

Can you try a different controller? I've had a couple of friends have problems with some Jetti 77s. Some work well some don't.

You might also resolder you motor and battery connections on the ESC in case you have a joint that is not quite as solid as it appears.

RK-Aircraft

My Feedback: (81)

I didn't think about the soldered connections. I still need to go through the process of elimination. I'll report my findings some time next week.

JetJock2140

My Feedback: (8)

Just one one more thing to check,,, if you have metal pushrods and or long extensions to servos in the tail of the plane that also can cause problems if the antennae is parallel to any of them. Had to move my antennae to where it was attached to outer edge of the horizontal stab on one of my planes and it stopped the trouble. May not be your problem but it can be a problem in any aiplane.

RK-Aircraft

My Feedback: (81)

No, I used the stock configuration. No servos in the tail, but I put a Deans two piece antenna on it just in case. I have a new JETI77. Hobby Lobby replaced the old one although they didn't tell me what was wrong with first one. I have yet to test it.

More later...