RunRyder - Glitch problem...

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Aerobatic FAI F3C Contest > Glitch problem...

saigon-heli
Senior Heliman
Location: Ho Chi Minh

Hi,

First, I am sorry, my question does not involve F3C. But I guess many of the F3C pilots use the same same equipment therefore I make questions in this forum.

I've built my Hirobo Sceadu EX (full carbon) with OS 50 hyper engine, GV1 and GY611 set at F3C. I break in engine with 8 tanks of fuel (480cc/tank) and already had 6 flights after breaking in.

I have problem with the tail, although I have changed gyro sens from 35 to 80% but the tail seems drift when in hover mode. In the flying mode with GV1 OFF, the tail glitching too much especially when take turn (left or right), same like cracking flight that some 3D pilots do. When the switch GV1 ON, the glitch reduces but not 100%.

When hover, I tried to quickly turn heli to left or right, the pirouette rate is quite high, but when realeasing the stick, heli does not stop right at that point, it kind of swing a little then stop (just a second).

Here are some of my questions:

1. Does wiring the gyro and servo cables close to the carbon frame cause glitching?

2. I think, the glitching (my case) can cause by engine does not run smoothly. If so, what can I do?

3. Does any setting on the gyro amplifier that help to dampen the tail?

4. Is tail drift normal for all gyro? I have heard GY611 should be able to hold the tail steady. I have always corrected the tail during straight fly.

Any feedback/advice is welcome.

Thanks in advance,

01-03-2008 10:16 AM

poerQwa
Veteran
Location: Rotterdam, The Netherlands

Hi,

Assuming you do not use subtrim/trim in any flightmode my best guess is your engine tuning.
The governor is actually telling you your engine tuning is off.
A not so well tuned engine causes vibrations that are picked up by your gyro's sensitive sensor and is translated into drift.
You do not describe your engine situation but in my case such behaviour was always caused by a LEAN tuned engine.
It might be worth to doublecheck your engine tuning

p.s.
I'm actually building an Sceadu EX as well(but using the YS50).

p.s2
Link to gy611 manual http://manuals.hobbico.com/fut/gy611-manual.pdf look for TRK option

01-03-2008 02:36 PM

saigon-heli
Senior Heliman
Location: Ho Chi Minh

poerQwa,

I tried to turn engine again this morning (open needle valve), it is one turn opened now.There is a lot of smoke, I think it is not lean or rich. But it does not help. It glitches hard only when I turn the heli, soft glitch in hover or straight fly.

My set up as following:

On my radio (T9CHP):
CH5>Sw-B
[GYRO SENS] MODE>GY
MIX>ACT
RATE-NORM>AVC 75%
IDL1>AVC 72%
IDL2>AVC 72%
IDL3>AVC 72%
HOLD>AVC 75%
SW>Cond
[SWASH->THR]
NORM>10%
IDL1>10%
IDL2>10%
IDL3>10%

On GY611 amplifier
G75a
G:1A100%
ACGA120%
D1IB 0%
D1DB 0%
Trk +0%
Mode CMT
FMod F3C
AVS 100%
LmtA 100%

Any one knows how, please help.

Thanks in advance,

01-06-2008 11:58 AM

Bruce Naylor
Senior Heliman
Location: Swindon, Wiltshire, UK

.... is that a Van DeGraff generator I see?

The carbon tail boom is insulated with a plastic support from the sideframes - try linking the boom and frames with some wire (scrape the epoxy away to get good conduction).

If it helps with the glitching, then ground all insulated carbon parts in sight.

Don't you just love carbon!

B.

"If you know what you're doing, you're not learning much"

01-06-2008 12:12 PM

saigon-heli
Senior Heliman
Location: Ho Chi Minh

Bruce Naylor,

So, what you say is to link all the carbon parts together? Why? Can you explain more? Do you have any picture?

Thanks,

01-06-2008 02:32 PM

JuanRodriguez
Elite Veteran
Location: Rochester, New York

saigon,

While I don't own a Sceadu, I can tell you that your rotating tail rotor belt can create static electricity to the point of "discharge"..... it is that discharge that can cause you a "glitch" in your system.....Carbon has a lot to do with it because the material is an electrical conductor.

When the JR Vigor first came out (all carbon machine) , they had one heck of a problem with "lockouts" (and LOTS of crashes !) caused by static. Once the "cure" was found, the problems went away. I believe it was Curtis Y that came up with the solution.... ie, placing a brass "strap" (of sorts) electrically linking the frames together.... sanding the carbon where the strap was installed was a must....

Getting back to your situation, if belt static is causing your problem then grounding the boom to the frame may be the solution.....

That being said, I seriously doubt that your "drift" is being caused by static....... but don't know for sure if that's possible....

01-06-2008 03:08 PM

saigon-heli
Senior Heliman
Location: Ho Chi Minh

JuanRodriguez,

Thanks for explaination, I will try to link the carbon tail to the frame and test next week.

Does any one has the picture of "ground" carbon tail to the frame? (Just to know how to do it right first time).

Thanks,

01-06-2008 04:55 PM

pchristy
Senior Heliman
Location: Nr London, England

One other thing to check: Are you using a voltage regulator or the standard 4-cell NiCAD (or NiMH)?

If you are using a regulator, try replacing it with a standard 4-cell set up. Make sure the pack is at least 1900mAH, and use a heavy duty switch / harness.

I have known a lot of glitching problems go away when you use a basic battery set-up!

--
Pete

01-07-2008 12:48 PM

saigon-heli
Senior Heliman
Location: Ho Chi Minh

pchristy,

I am using JR 1800 mAH and Futaba heavy duty switch.

Thanks,

01-07-2008 04:41 PM

pchristy
Senior Heliman
Location: Nr London, England

<I am using JR 1800 mAH and Futaba heavy duty switch.>

That should be fine!

I have known regulators cause problems in the past, and its the first thing I recommend checking, if one is being used!

Good Luck!

--
Pete

01-07-2008 07:06 PM

saigon-heli
Senior Heliman
Location: Ho Chi Minh

JuanRodriguez,

I tried to ground the frame & tails this morning, adjusted tail servo to ensure no vibration from the frame to servo.

The result is still the same, whenever at high RPM and turn left or right the tail glitching hard, you can hear zu zu... like 3D cracking.

I do not know what to do now. Do you think that to shift the sensor from the back to the front could solve problem? Or tight the sensor down to the base (I saw some one does) will help?

Anything else that you suggest to check?

Thanks,

01-13-2008 02:12 PM

JuanRodriguez
Elite Veteran
Location: Rochester, New York

Hi Saigon,

Can you take a picture of how you ground the system ?? Did you sand the shiny surface of the carbon for grounding ??

The location of the sensor should not matter....I have seen both locations used on other helis. The way you have it installed now looks good to me.....

It could also be the settings on your gyro causing you problem.....

I'm not familiar with the 611 but I'm sure there are many out here that can go through the settings with you....

Lastly, it is possible that you have a defective unit.... Can you borrow another from a friend just for testing purposes ??

I wish I could be more help, sorry....

01-13-2008 02:21 PM

saigon-heli
Senior Heliman
Location: Ho Chi Minh

JuanRodriguez,

I connected the aluminium of tail grip to main frame.

Anyhow, thanks for your message.

Regards,

Son

01-15-2008 11:32 AM

mdu6
Veteran
Location: Montreal

From your description, I don't see necessarely only a glitch problem.

I would try to get that part working right:

When hover, I tried to quickly turn heli to left or right, the pirouette rate is quite high, but when realeasing the stick, heli does not stop right at that point, it kind of swing a little then stop (just a second).

It seems you are running the 611 at 75% gain ...

RATE-NORM>AVC 75%

On GY611 amplifier
G75a

I know you said you started around 35% (which sounds right). Can you put it back at this and see if the hovering/pirouette are OK.

Also, what is the ATV setting on Rudder ?

01-15-2008 03:05 PM

Kader
Senior Heliman
Location: Czech Republic

Hi saigon-heli,
try replace the sensor with another one to recognise defect .Our sensor 611 after middle crash did the same problem, as you describe. My friend dismounted the sensor case and he found , that the sensor is already slack in his rubber box and kick agains bottom of sensor case. He put four 3x3 mm square double side tape about 1mm thickness on the corners of sensor between sensor and case.
It helped immediatelly .

JAN

02-21-2008 11:58 AM

saigon-heli
Senior Heliman
Location: Ho Chi Minh

Hi all,

After so many tried I have found the problem for my case, what I did was

1. Rewire the sensor cable, separate with the servo cable.
2. Drop the gyro sens to 45%

It works fine now. Thanks for all of your help.

02-25-2008 09:02 AM

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Aerobatic FAI F3C Contest > Glitch problem...

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