Phil,
Just a comment about swash leveling and zero'ing the pitch at mid stick (screen shot 3)
Your instructions appear to suggest that you first level the servo arms, then if the swash is not level or pitch not zero at mid stick you further adjust the arms with subtrim sliders to get the swash and pitch correct (meaning the arms are no longer level). Possibly I'm misinterpreting the instructions but if that's what you are intending to say it isn't the correct way to do it.
To get a proper setup you must have (at mid stick) ALL of these points correct:
- All servo arms precisely level
- Swash level
- Zero pitch
The only way to achieve all of these three points is that you first precisely level the arms using the subtrim sliders in the software to fine adjust (easiest done on many helis with servos out of the heli).
After precisely leveling the arms you must not adjust their subtrim sliders any further. If there are any errors in swash level or pitch that must be corrected by adjusting the linkages. The linkage length suggested in the build instructions is just a starting point and will often need to be adjusted slightly to compensate for individual servo geometry and minor variances in servo position when they are mounted.
Hi Steve, thanks for looking into the text so closely. I'll have a good look at the original to see if I've made a misleading statement and create a new slide similar to the new one I did for the tail issue. I've begun preparations for a video but can't say right now when I can finalise it. Maybe I could break it up and publish smaller sessions.
Regarding the swash plate levelling and pitch setting......... Is your observation from experience with the Spirit or your wider knowledge/experience? I'll try and explain the process I used as follows:
The Spirit instructions wander around a bit so I've had to study them carefully and re-write them to consolidate my understanding. The slide show was a means of summarising this.
The rotor head is removed and the levelling tool fitted. When the tick box is selected in the 'Sub Trim (tuning)', the stick doesn't do anything, it's locked out. The servo spindles all assume their mid position, which according to Spirit can be slightly different. This was the case with my servos, hence, the slightly different values to get the arms perfectly level after a number of attempts placing the servo arms for 'best fit'. Thanks to Neil on this one as he was the main driving force for me keeping at it.
I had already reported a slight tendency for the heli to tip left when going light on the skids and this turned out to be caused by the Aileron servo not having enough travel as the swash plate moved down. Fortunately, I don't normally use the full travel so this wasn't a big issue for me at the time and to err on the safe side I also relegated my JR Tx to be my simulator Tx only.
So, still with the head removed and a perfectly level swash plate, I went into the 'Servo Travel Correction'. This releases the servos to respond to the stick, hence the opportunity to test the swash plate travel over its full range. Again, Spirit mentions the possibility that the servos may vary slightly at the extremes of their travel. This was indeed the case for mine and I was able to correct it with the sliders. The swash plate stays perfectly level throughout its travel as confirmed with the levelling tool. I moved the sliders and my Tx servo limits in combination until neither were in conflict.
After removing the levelling tool and refitting the rotor head, I was able to confirm the settings with the digital pitch gauge. -12.0, 0.0 and +12.0. These are the exact numbers quoted by Align in my assembly instructions and are maintained constantly since completing. Since I bought my turn-buckles I can adjust the pitch perfectly. One blade was -0.1 and the other was +0.2 degrees. I used the exact measurements from Align for the link rods and my best interpretation of the Spirit instructions regarding the set-up.
I did not move the Spirit's 'Sub Trim (tuning)' sliders again or the Tx. sub-trim adjustments and have a perfect swash plate set-up. I disagree that there should be any reason to change the length of the three swash plate links unless it's by exactly the same amount on all three and then only slightly. Since buying my digital calliper, it's possible to measure them perfectly. I had considered buying three turn-buckles for them as well but that's proven not to be necessary. Well done Align!
Look forward to our next exchange.
Bye for now.
