Hi

I have a Raptor 30 whose tail is very erratic and I need some help! I simultaneously upgraded the following:

1. Installed header tank
2. Carbon boom supports
3. Rear mounted tail servo
4. Faster tail servo
5. Home made ali cooling duct extension

After doing the above I cannot achieve a stable hover as the tail will flick one way and then the other, sometimes quickly othertimes its more of a drift. I have reversed the above so all I am left with is the carbon boom supports and rear mounted servo, but still the problem persists.

The gyro is a simple piezo affair mounted at the fron near the receiver. In order to reverse its sense for the new servo I had to remount rotated 180 degrees. I had to use dinew mounting tape and my question is: does the kind of mounting tape have a big bearing on how this kind of gyro acts? Is it important to use exactly the same type as was supplied?

Please shed some light as this is driving me crazy!

tape should not make a big (if at all) difference.
check what it is doing in non-tail lock
check the gain
check the direction of the servo (it sound like something is going the wrong way/ the servo or the gyro)

When you said you rotated the gyro 180 degrees, do you mean you simply turned it around half a turn or did you turn it top for bottom. Turning it around will not reverse the gyros output, if it doesn't have a reversing switch, you will have to put what was the top on the bottom.

when mounting the servo at the boom you could have easily switched direction of the servo, check that...

Thanks for the replies.

The servo is definately operating in the correct sense. When I turned the gyro it was top for bottom and I checked and double checked that it is working correctly - I even compared it to a friends Raptor.

My thoughts were that the gyro was not being sufficiently shielded from the engine vibrations as I am not using the original mounting tape - which was very thick and would absorb vibration well.

Sounds like the gyro servo is in the correct 'sense'.

My hunch is that the faster servo, possibly combined w/
the new gyro tape is letting you see a mis-tuned engine.

However, mounting tape does make a difference. You can
certainly try a different tape, thats easy and you might want to
try adjusting the engine mixture too.

IMO, the little shelf behind the mainmast is a better location.

All the pics, and everyone I know mounts it at the back. Does it matter if the gyro's mounted in the front or the back? I'd imagine if it was mounted up near the reveiver it wouldn't know really how much the heli is rotating.

But what the hell do I know.

the gyro, performance-wise doesn't care where. It measure
angular rate or acceleration and that is a constant either on
the front plate or the rear deck.

Vibration isolation is a whole different story through and
that is where the 'compliance' of the mounting tape and stiffness
of the mount point comes into play.

GaryC,
Just a thought since you seemed to have checked everything else that would cause the problem.
Are the thrust bearings in the tail in the correct way if it does have thrust bearings?
If it has thrust bearings them being in the wrong way can cause what your problem is when the tail is turning the RPM it would take to hover.

David

Thanks for the input Guys

I believe I have sorted the problem out by getting some of the original mounting tape. I also reduced its sensitivity and it is now holding the tail well.