Moved mine to the Logo 14 now.Same thing, plug and play.
Spent some time helping Kenny with is JR 5000 (wash my mouth out) yesterday but ended up thinking why do they put themselves through all this.Nice guy,very good flyer,just needs a 720.

Flybars. Who needs `em.

Recently installed a CSM720 (to replace my 601) in the front of my Raptor 90SE and used a Futaba 9254. Setup was very easy I didn't even have to adjust the throws of the gyro in the quick setup - it was as if the gyro was made for my heli
It flew great from the beginning with no tweaking. Great gyro and it has a really great feel in piros!

Henrik

and it has a really great feel in piros

I couldn't agree more!

Sponsored by CSM and QuickUK

I must agree, the 720 is the most Piro-Consistant gyro i have ever flown.

www.liorzahavi.com

I'm also a very happy 720 owner.

It is very easy to set up and it's holding the tail like a rock!

NO problem with drifting (evean that the engine is not broken in) and NO problem with drifting on my Gasser (I had problem with my Footaba 611).

/N

it was great!!

I've had several flights with my 720/9256 combo in my R90 and it has to be possibly the best gyro i've flown but.... had two flights with it tonight and its drifting like mad, whats changed!!!?

Was it supposed to do that!

Same problem here on an Avant. The CSM 720 Futaba 9256 flew great for a couple of flight than it started drifting and i can't get it back to work properly.

Corrado

I think the first thing to check is for any servo movement on the ground in Mode 1 (heading lock). With the stick centred (and of course no trim) the servo should be still or move at a rate equivalent to less than 5 degrees a minute of heading change (less than 10 deg/minute of servo movement even at high gain settings)

Please check that and let me know what you find.

Best regards

Colin (CSM)

Mine moves faster than that with the heli on the ground.

Corrado

Hi Corrado

It would be worth repeating the quick setup routine by toggling the mode/gain switch during boot up. (there is no need to go all the way through the quick setup - it is enough to enter quick setup, wait for the servo to zip in acknowledgement and turn off again). This will ensure that the stick centre value is accurately aligned with the zero of the yaw rate demand of the gyro. You should find that the servo motion is within the spec mentioned above after that (each gyro is actually checked to be within 3 deg/minute with a 20 degC temperature change between turn on and operation).

Best regards

Colin (CSM)

I have found that when the servo is moving when the heli is on the ground is realated to movment of the heli during the boot up of the gyro.

I just turn it off and turn it on aging. It is VERY importand to not move the heli at all during the boot up. Sometimes it's moves my the wind or when the hand's are removed from the heli. Espescily when the heli is on a hard bench or someting like that.

Just my 2 cents...

/N

something i've noticed

My 720 didn't use to drift but it only does it in HH mode, no trim or mixing in what so ever but now it goes up to one end and if i center it goes back! i'll try the quick setup again and reset it see what happens

Was it supposed to do that!

I'm confused about how to enter/activate Quick-trim mode

From the docs:

...

Hover nose into a moderate wind or fly in slow forward flight. Activate the quick-trim by switching the gyro gain/mode switch on your transmitter back and forth five times
between the two gyro modes. Hold each mode for about 1 second. The right timing for this is easily obtained by counting the clicks of the switch out aloud
to yourself as you do it. If the tail push-rod length adjustment is reasonably correct the Quick-trim will now compensate for the remaining error and the
model should fly straight in mode 0. If not, repeat the Quick-trim sequence. If, having repeated the Quick-trim, the mode 0 trim is still wrong the push-rod
length is outside the range of the Quick-trim system and some mechanical adjustment is required.

Ok.

First, how to activate? Assume flight mode normal is gyro mode 0 (rate mode), and flight mode 1 is gain mode 1 (heading hold). I have a yaw to the left. Is quick-trim activated by hovering/flying in

gain mode 0 for 1 second
switch to gain mode 1, hold for 1 second
switch to gain mode 0, hold for 1 second
switch to gain mode 1, hold for 1 second
switch to gain mode 0 for 1 second?

Or is it hovering/flying in

gain mode 0 for 1 second

for (i = 1; i <= 5; i++)
{
switch to gain mode 1 then quickly back to gain mode 0
wait 1 second?
}

?

If I have a slow yaw to the left, can I hover into a wind letting the helicopter rotate (no rudder stick input) while I do the gain 0, gain 1 thing?

Hi Rick,

This is one of those process's that is very easy to show someone how to perform correctly in 30 seconds, but sounds 10 x more complicated than it actually is when you try to explain in words.

Firstly, the 'quick-trim' is not used to stop any drift in 'heading-lock mode' but to simply obtain the correct trim in 'non-heading lock mode'. You can start the 'quick-trim' sequence in either 'heading-lock' or 'non heading-lock' mode. When toggling the gain switch to activate 'quick-trim', you should notice the tail stops moving less in normal mode each time you toggle. If the tail still moves in 'non heading-lock mode' after you have performed quick-trim, then this indicates the amount of tail pitch at neutral in 'non heading-lock' mode is too far from the correct value. The best way to achieve the correct value (approx 5 degrees right tail at neutral) is to hover in 'non heading-lock' mode and adjust the length of the linkage until the tail remains stationary in the hover.

If the tail is drifting in heading lock mode, then start by re-entering the 'quick set-up' routine, but firstly be sure that the rudder trim / rudder sub-trim is at neutral in all flight modes. The gyro then senses the TX rudder stick neutral position and stores the information.

If you are still experincing drift in heading lock mode after the above, then the 720 sensor is very predictable in it's nature! Any slow drift in heading lock is caused by high-frequency (engine type) vibration. This can generally be cured by ensuring the gyro is mounted on 4 x small soft pads as advised in the manual. If the gyro is mounted in this way and still drifts, then you may have to change the location of the gyro or check the set-up / alignment of the engine / fan / clutch is not causing excessive vibration. Proving the drift is caused by engine vibration can be checked by hovering at various headspeeds. If the tail drifts more with a higher headspeed it is a very clear indication of excessive vibration.

I hope this helps and please get back to me if you require further clarification of any points etc.

Russ Deakin (CSM Tech Support)

Russ,

Thanks for the reply.

I did have to shorten the pushrod by three turns to get the rate mode yaw or 'drift' stopped. Heading hold mode was ok.

Now onto another question.

The SL 720 is replacing a GY401 in a Raptor 50/OS 50 Hyper. I am using a 9254 servo. What concerns me is the servo temperature after a regular flight is as high as 135F (range is 125 - 135F). I tried to get readings using the GY401 and they seem to group around 115-120F. Ambient is 95F. While the SL 720 does work better, and I can see that it does so by working the tail servo more, and I am concerned that this is going to make the servo fail. Would you suggest that I examine the machine for problem areas, or is a servo like the 9256 in order? The overall hold of the tail is much better than the GY 401.

Rick

Hi Rick,

I have tested 9254 servos on a 720 in a Raptor 50 and did not notice any un-due heat by touch. I have however not run one for a long period of time and I confess that I did not take any temp readings. The servo will be working harder if the tail is holding / performing better, but I would not like to qoute an acceptable temp range for a good servo life on the 9254.

If the model/engine is causing any undue servo activity, this would show in the hover as a motion on the tail. Perhaps the safest route for now would be to drop the TX gain by 5 - 10 points and take temp readings.

I am very much hoping someone with a lot of experience of 9254 servos may be able to step in here and advise of acceptable servo temps for good servo life (please)????

Russ Deakin (CSM Tech Support)

Hi Rick

One thing you could try is to do a test hover in flat calm conditions (little turbulance) at a much lower gyro gain (say only half the current value) and have a look what happend to the amount of tail movement. If you see an increase in the tail motion then you know that there is some fluctuation in torque delivery from the engine. These can be a significant cause of tail servo activity with the gyro/servo constantly trying to track the torque changes.

I have talked to a number of pilots who have found a significant improvement in smoothness by reducing the compression ratio of the engine (where being used with a tuned exhaust). Try say about an extra 0.5mm shim under the head and see how that affects the tail movements.

On other thing. What length arm are you using on the servo? If its less than 20mm you may reduce the angular throw of the servo for a given pitch change by increasing the servo arm length to 20mm. So long as the tail loads are modest this should reduce the power consumption a little.

Best regards

Colin (CSM)

Hi.

I tried the extra head shim idea and that did help the engine run a little smoother. Servo temp before and after the change were about the same.

I tried another muffler (still with two shims) and that really helped smooth the engine out. Its not perfect but much better. However this smoothness cost engine power. Initially servo temperature was slightly reduced, but as I had more fun flying with the smooth running engine, I flew a greater envelope, and that raised servo temperature. Mixed results for this test.

On a calm day, I'll try Colin's suggestion to see what it brings.