Vario Acrobatic Gasser

As some customers have gasser helis and also trouble in setting up the governor right - i want to try it too. At this point i must say a BIG THANKS to Kirsten Zodtner (CEO of Vario Helicopter) for this excellent machine, the Vario Benzin Acrobatic.

The Heli is equipped with Savox HV Servos, Silverline VBar, V6 for VBar Control and a 2s Hacker 3800 mAh LiPo. Blades, motor and muffler are Vario stock, nothing special. Just as a customer can buy and built.



Basic settings in VBar Control for flying w/o Gov (waiting for Stator Gator):

At this point i was flying in throttle curve only (w/o RPM signal). The displayed values will give a headspeed around 1400 1/min. The Spoolup is done by VBar Governor automaticallay - just flip the motor switch ;-)



To dial in the basic values correctly w/o governor - here the procedure (which is also recommendable for nitros):

  • on Gassers - use mechanical throttle linearisation (the have lot of torque at low throttle)
  • set up throttle linkage in the setup panel (this includes the throw correction with idle there ...)
  • set runup speed to 2
  • use Bank1 for basic setup - but in governor mode. We prepare bank1 for non-governed usage first
  • zero out all values like collective, cyclic, dynamic add, differential, P Limit, Integral, Gain (10 will be rest)

So we have a non - governed mode now to use for basic throttle curve height and idle setting ;-)

  • use fixed idle (no poti)
  • turn down basic throttle to 10, min Limit to 2
  • start the motor, use idle with dial until idle rpm is ok.
  • put the heli on the field, collective to zero
  • now spoolup the heli with "run" switch (spools automatically)
  • dial in the basic throttle until you may get the lowest HS you want to fly
  • dial in the min Throttle approx. 10 points less than basic throttle, but minimum 5 points
  • dial in the collective add until the HS is approximately the same in a hover

Basic setup is finished here ;-)

  • dial in the gains, other adds, etc. you have zeroed before
  • dial in the estimated values above to all banks (integral shifts them to the right height now)

or to be perfect:

  • do the same procedure for the other Banks / RPM.

And from now on:

  • to spoolup the heli - just flip the switch as on a electric ;-)



Here a screenshot of the Vib Analysis in a hover, nothing to see here



Some maiden flight impressions:



So ok - but at the maiden flight i mentioned some tail wag and the tail servo gots a bit hot also. I had this previously on the bench too - and the reason was just simple: The tail rod support and the rod are fitting very tight together. Too tight in case of cold weather. The support is also a kind of rubber which let the rod not run as smooth as it could be. No biggie - but it could be better using the Mikado Part #04139 from the XXTreme 800. This is another material and has more space for the rod.

Another thing to do was some kind of antenna holders - i took a visit at Mc Donalds and grabbed them (wooden sticks for coffee) there ;-)

As i missed some kind of a horizontal fin at the tail boom support clamp (looks a bit like "not finished yet") - i took one from a Logo 600 and fixed it to the clamp. Looks much better



Today i installed the Stator Gator RPM Sensor. I was waiting for it several weeks due the christmas holidays - but at the end it arrived here in Germany w/o having trouble with the customs. I'll give it a try altough it would be possible to use a magnet hall sensor on the main shaft too. But i like solutions w/o mechanical adds - and so the SG was my first choice here.

One thing has to be kept in mind: The VBar RPM input allows a Voltage up to 5V. The SG works with its provided voltage - so usig it on a 2s setup may not work properly. using it with 3.3V from Sensor2 port is too less for the SG itself.

I bought some 7805 voltage regulators (5V fixed) which are very cheap - and can handle up to 2 Amps. Just get the ingoing voltage from a free port of the VBar, and output goes to the SG connector. The signal pin was removed there and has a external housing, then plugged into Sensor2 (orange marked pin).



So - i headed out to the field, being curious how the SG works. Well - what should i say - it just works. No RPM sensor entries in the log, RPM reading was shown correct on the display. After some fine tuning and dialing in the governor parameters - it ended up with this values for 3 headspeeds:



After getting used how to fly such a helicopter - and flying it through some stunt maneuvers i noticed a kind of latency in cyclic commands. Also some light wobble effect (could be triggered with a small stick input) was noticeable. Well - i have been building many helicopters and also seen many rotors - so i had a idea what could be optimized here.

The Vario main head has just one dampener (rubber ring) each side. So the blade grip spindle has some play here after these 2 rings have been in use and are getting softer through the flights.

With my limited possibilities i thought about using a old (2 pieces) Mikado Logo 600 main head - but as it is made for a 10mm shaft - i had to make one piece new on a lathe, which i don't have. But - a clubmate has one and he offered me to do this for some beers ;-)

So this is my new main head - made of Mikado Logo 600 parts (hardest dampening), some shims, the Vario spindles and blade grips and a custom made hub for 12mm main shaft using the original Vario clamp to fix it. Also some new linkage rods have been needed of course.

About the flying with it - as expected. Precise, no wobble, no latency - it just works.






Conversion to VBar NEO


After succesful flights with the Silverline VBar i deciced to convert this gasser to a VBar NEO. As the neo could handle RC Voltage on the RPM input - it would allow me to pull out the voltage regulator. But - the manufacturer of the Stator Gator told me it would be better to feed the SG with max. 6V - and so the voltage regulator still stays in the heli.

I mounted the NEO on the gyro plate at the tail section. This plate is connected to the frames at only 2 points, so the plate could move a bit with vibrations. But at all - there was no problem in flight. Anyway - as technician - this isn't a correct way to mount a gyro plate - and so i added two additional "L"-shaped aluminium profiles to support the gyro plate in the back. 

With my flying skills - i didn't find any noticeable difference between the external Silverline (still in heli, can be used on a NEO) and the internal sensor.

The NEO has a new designed nitro governor - and so the values are a bit different from the values above for the Silverline VBar.