SL720 & SL630 Gyro Troubleshooting

The gyro will not enter the Quick-Setup routine

The gain is probably too low - increase the gain for both modes to 100% for now, and return them to the desired setting later. Remember also to turn off ATS (revo) mixing.

The model pirouettes violently as soon as it starts to lift off

The gyro sense has been set incorrectly. Check that the servo operating sense has been set correctly - when you put in a left turn command, the leading (fatter) edges of the tail rotor blades should point right. If this is not happening, change the servo reversing of the tail rotor channel in your transmitter. Then repeat Quick Setup to set the gyro sense correctly.

The tail wags from side to side in the hover

Reduce the gyro gain, using the ATV/travel adjust on your gain channel

The model flies fine in one gyro mode but wags in the other

You have too much gain in just the one mode. Reduce the gain on the mode that wags.

The tail response is not crisp enough

Increase the gyro gain. It is best to increase it gradually, until you see the tail start to wag, and then reduce it again until the wag stops.

The model wags even when the gain is very low

The problem is probably with the linkage - check that the linkage is not suffering from slop or friction, and that the tail hub bearings do not lock up under load. You should also check your servo. A slow servo or a very short servo arm may also cause this problem.

In mode 1, the model slowly rotates

Carry out the Quick Setup again, so that the gyro can sample an accurate stick centre value. Remember to keep the stick trims centred, and not to touch the sticks or the model during the power up time.

The model hovers well in mode 1, but rotates in mode 0

Repeat the Quick Trim procedure.

Even in calm conditions, the model suffers continuous small movements of the tail. It sometimes appears to drift.

The problem is most likely to be caused by vibration. Check that the wires leading to the gyro are properly supported - a long stretch of flapping wire may cause the gyro to move too much, and an over-tight anchorage may prevent the anti-vibration mount from working correctly. If you cannot eliminate vibration, try turning on the Vibration filter in Quick Setup.

An alternative cause for this problem is fluctuating engine torque.

The model flies fine on the first flight, but after a while the tail starts to wag

Fast gyro and servo combinations can run down the battery. Cycle the receiver battery and check its performance. You should consider using a fast Delta-peak charger to top up the battery between flights.

The model was fine last season, but now the tail wags

Check that the tail control linkage moves freely, paying especial attention to the pitch slider and the tail hub bearings. The receiver battery may have developed a high internal resistance - cycle the battery and check the capacity. The capacity may seem normal at low discharge rates but drop suddenly at say 3 amps.

The left and right hand stops are not equal. On one side the stops are slow and on the other they are bouncy.

Carry out Quick Trim, and make adjustments to the linkage if necessary (see the manual for details). On the SL720, if the problem continues, use the PC interface to adjust the left and right stop gains. If the problem still does not go away, reduce the servo travel limit for right pitch if the stops from left hand turns are bouncy, and reduce the left pitch travel if stops from right hand turns are bouncy.

I am running a high gyro gain, but the stops from high-speed pirouettes are still too slow.

The maximum available tail thrust is too low. The best ways of increasing the tail authority are: increase the pitch range of the tail; change the tail gear ratio to increase the tail rotor rpm (only possible on some machines); increase the length of the tail blades. Caution: when increasing the tail blade lengths, check that there is still sufficient clearance between the tail blades and main blades. If you cannot increase the tail blade length, then increase the chord of the tail blades.

The model twitches erratically and violently in yaw.

If you are using a belt-driven tail, then the problem is probably static electricity. If this problem is not sorted, then it may cause damage to the electronics on your helicopter. An anti-static spray on the belt is the easiest solution. It is also possible to get grounding systems which ground the electricity safely. The latest versions of the SL720 and SL630 have the feature that if the gyro sees a static discharge, or a power dip or surge, during flight, the SET LED will be flashing on landing the model.

The following downloads may be of use to you:.

SL720 Manual - pdf format.................SL720 QuickReference card - pdf format

SL720 PC Interface Manual - pdf format......... SL720 PC Software - zipped file

SL630 Manual - pdf format.................SL630 QuickReference card - pdf format

Please make sure you have set up the gyro carefully according to the manual.

If you are still experiencing problems, please contact us at tech@csm-ltd.co.uk or by calling 01457 854680 (0044 1457 854680 for callers outside the UK)