Gyro problems after Stratus conversion

[Nige]

The 601 gyro drifts after conversion!

I have just converted my newest Fury to a Stratus, the donor model has never been damaged. The model has a YS91 MP2, HD clutch and open tailbox.

The gyro does not drift on the bench in any mode.


To try and find the problem I have:-

1) tried different gyro tape with and without the metal plate.

2) changed to another engine and fan from another machine.

3) changed the entire clutch assembly from another machine.

4) changed the gyro sensor.

5) changed the main and tail blades and flybar

Any other suggestions?

Thanks

Nigel

[DavidH]

I would look for something in the radio program that is causing it.

Subtrim?

Mixing on tail rotor?

Trim being off centered?

Sounds like you have eliminated the normal causes. But you didn't mention anything about the radio.

David

[Zilly]

When I mounted my 601 sensor onto the Stratus I made a slightly bigger base by epoxying on to the metal plates a piece of old G10 frame, without this I felt the gyro was not mounted securely as it overhung the frames either side. I noticed from the instructions they suggest using a piece of velcro to secure the gyro. I dont like the idea of this hence the plate which allows the gyro to adhere properly, its not going to come off in a hurry.

z

[Laurens]

Vibration causes gyro's to drift. Check if you still have drift while idling.

[Scrub]

I had the same problem. I re-adjusted the gear mesh in my T/R which resolved the problem. - Good luck!

[Clintstone]

I have done 4 of them and I had onl one problem...........left heli in truck on a hot day and lets just say I am thankfull for that velcro I wrap over the sensor. It first started with a drift and then It got worse. Last year before IRCHA I had a sensor go bad and luckily this time I only had to re tape the sensor and it worked great. I don't recomend making any mods to the Stratus as it is great right out of the box. Good luck..............try taking off the mods. and let us know. Could merely be a coincidence. Good luck......the drift drives mee crazy!!!!!!!!!!!

[EricLarson]

Drift is caused by vibrations some place. It may be hard to find. Also different gyro tapes work better. The stock Futaba tape does not work that well. You may want to use 2 layers or something a bit thicker and softer.

[Dr.Ben]

My model exhibited the problem, and I know another MA team member that is having the same issue. It is a vibration related phenomena.

In my case, the gyro sensor now sits on a homemade mount where the rudder servo normally rests, and the t/r servo is on on a rear mount. This had to be done in my case anyway since I use a FAI tail and at the time I got my kit, the FAI frames weren't yet being cut. When I moved the sensor, the drift stopped.

As Eric suggested, fiddle around with the tape combo, thickness, etc. Confirm there is minimal high frequency vibration in the model as well.

Ben Minor

[Nige]

Thanks for all the suggestions,

The radio has no subtrim or trim in any mode, i have also tried initializing the gyro in Idle2. No drift on the bench or at idle

I also tried making a platform for the gyro to try and change the transmitted frequency, tried multiple/single layers of softer/harder tape with and without the metal plate.

Next I will:

Recheck the balance of the fan

See if I can get the fan runout below 1.5 thou that it currently is.

I will change the 'uniball' for a new one.

Change the entire tailbox for the old closed one.

change the muffler to an sb16 from an mp2 (just to see if the frequency is changed)

Then throw the thing in the bin :arggg:

Ben: any commonality in spec? YS engine? Mp2? 1800 rpm on head, 8:18 gearing. HD clutch, open tailbox. FAI pitch slider.

[EricLarson]

I chatted with a few other people about this type of problem. It almost always shows up in a carbon model but not G10 or plastic. It is vibration related.

The fan needs to be less than .001 in a carbon model.

Most likely though the cause is the rear bearing in the motor if you have already tried all of the stuff you said. If the bearing is older than 2-3 month it is causing vibration issues and those usually show up in the gyro.

Also you can try sticking the gyro sensor to the bottom of the radio tray. It is better isolated and I know it works fine there. If that fixes the issue you can leave it there, but the cause of the vibes is still there someplace.

Good luck,

Eric

[capebob]

I found some really great mounting tape at Radio Shack. It did wonders for my Stratus that was having a resonate vibration problem. The tape solved the drift and the vibration problem went away after about two gallons. I suspect the open tail rotor gears because I set them up a little on the tight side, so tight that they showed a little roughness. The roughness and the vibes are gone and the drift is a thing of the past. The tape is "Hi-Temp/ Hi-Strength Supermount Tape". Part # 64-2361. BTW my fan is balanced and runout <.001.

Bob

[Dr.Ben]

Nige:

YS91
7.9:1
Hover rpm 1470/1950-2K upstairs (F3C)
Open tail box
Fan run out <0.0005"
SB-16

Ben