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Flight Characteristics questions

Posted: Fri 10. Jul 2015 0:10:56
by Scott H
I did my first flight today with the Spirit on a DT700, no governor.

I noticed three flight characteristics that I've never seen before:
1)In forward flight the model slowly pitches down - Do I adjust the "elevator pitchup compensation" down - usually the models I've flown with other fbl systems I'm always fighting the model pitching up.
2) If in Forward flight I often run the tail to the left or right causing a full but only moderate speed piro (while continuing forward flight), when I did this today and at the portion of the piro where the tail was pointing to the forward momentum, the helicopter pitched downward. When I continued the swing so the tail was at the rear of the helicopter the heli reverted to the angle/pitch it was at prior to the piro. I've never seen that before. I'm guessing it's related to the same tune issue of number 1 above.
3) In testing the rescue feature (acro)- the aircraft leveled, but when I released the rescue switch the the heli tips back at some angle. 10 - 15 degrees (just guessing). What I know is that it doesn't stay in the level position and I did not have my fingers on the elevator/aileron gimbal.

I didn't tune the heli at all, so I'm happy to follow the tuning guide, but in the meantime, I thought I'd ask about these characteristics.

Anyway that was my observation. I've attached my saved settings file if that were to help.

Thanks in advance

Re: Flight Characteristics questions

Posted: Fri 10. Jul 2015 20:13:58
by ZeXx86
Hello,

thanks for your report.

It seems that all the problems are related to one issue. I believe that the issue is in cyclic servo settings.

Can you enable Subtrim (tuning) in the Servo tab and check if all servo horns are at 90° while the swashplate is perfectly perpendicular to the main shaft at the same time?
This settings must be done with a cyclic leveler, inprecise settings may cause this. At this moment it looks like horizontal position is in some angle - angle that is also visible when the rescue is disabled.

I do not recommend to change any other settings as this problem should not happen in any case when basic settings are OK.

Re: Flight Characteristics questions

Posted: Sat 11. Jul 2015 0:46:28
by Scott H
Zex,
You were right on. I releveled the swash using subtrims in the software (which I only eyeballed my first time through).

I just put one flight on the machine... all three of those tendencies are gone. I'm looking forward to flying the machine with this unit. After a few more flights I'm going to try to follow the instructions and get the governor working.

Thanks
Scott