Multiwii Beginners Guide to Basic First Flight
First & most importantly calibrate ESCs min/max points using direct connection to RX. There are other methods but this is easiest. Ensure motors are turning in correct direction with correct props for rotation & not mounted upside down
Next connect to PC running WinGUI or MW Config. Calibrate ACC with FC level & not moving & Mag by moving FC thru all axis in 30seconds. Check graphs & readouts to confirm accurate calibration.
Set your transmitter end points. Using the WinGUI or MW Config open the RC CONTROLS tab look at the live tx data, then use your tx sub trim to set the throttle low at 1000 and all the mid sticks at 1500. Then using the tx end points adjustment make the throttle high point 2000, yaw left 1000, yaw right 2000, pitch dwn 1000, pitch up 2000, roll left 1000, roll right 2000. You may have to readjust for 1500 centre. Ensure that all readings move in direction of TX sticks & switches. Reverse on TX if not.
All flight modes disabled apart from Acro and mag. With all sensors calibrated correctly and mag declination set, using the default PIDs and in a nice open space ARM with throttle low and yaw right. Increase throttle slightly then decrease throttle fully and the motors need to be still rotating, if they stop then your min throttle setting needs increasing slightly.
Try again and if the motor idle speed is stable increase throttle quickly to approx. 50% and hover. If it drifts use TX trims to prevent it.
Next enable Horizon mode. If quad drifts backwards just land disarm with throttle low yaw left. Then trim ACC with throttle high and hold your pitch roll stick in the opposite direction to the drift so in this case forward hold there until the light on your board flashes 5 times then centre stick, throttle low and rearm and try again. Repeat as required. DO NOT touch TX TRIMS to counter drift as you have already set this in Acro. Remember If you calibrate ACC again using GUI (or ACC stick Cal) you will lose these ACC adjustments & have to do it again.
If motors don't have enough power to climb then vibration is probably your issue unless bad or low capacity Lipo. Buy good composite or CF props with quality adapters, balance everything & then retry. You may still need to set Gyro filter to 42Hz in Config.h if it won't climb or flies erratically.
You should now have a nice stable quad (or at least as you can get without PID adjustment) & can then move on to GPS modes for which you will find plenty of info on in this Forum. I hope this will help you and maybe others to get flying. It's a big learning curve but definitely worth it!
NOTES 1. Don't expect motor speed graphs to rise in sync & hold speed in GUI when quad not flying. This is normal & part of PID control
2. Most FCs (flight controllers) come loaded with older versions of Multiwii. Download latest versions of FC Firmware & MW Config & WinGUI (currently 2.3) from http://www.Multiwii .com. Configure for your quad & upload to FC. It is imperative that the firmware on FC & WinGUI /MW Config are same version
3. If you intend to use advanced GPS functions such as Missions, Land, Fencing etc, download MW2.3 NaviB7 for FC & WinGUI pre 10 for NaviB7 from http://www.eosbandi.com These GPS modes beyond Pos Hold & RTH require an FC with Atmega 2560 microcontroller. The Crius AIOP V1 & V2 are typical. Configure for your quad & upload to FC
4. Be aware that if you choose to run the MW version preinstalled on the FC it may have Motor_Stop uncommented. This is not recommended for beginners as motors will not spin on arming & you will not know if Min Throttle is set correctly. Min Throttle should be set to lowest speed that will cause all motors to start reliably every time that quad is armed
Happy & safe flying
Cheers..B