F450 Crash need help to determine why

About a month a go I decided to get into rc multicopters so I purchased an F450 kit from ebay.

while I was waiting for the F450 to arrive I researched and purchased all additional parts and equipment needed to build the quadcopter. it took about 2 - 3 weeks to get everything need together so I had plenty of time to research configuration and build on youtube.


The F450 consists of the following conponets:

F450 Quadcopter clone

Heightened Landing gear

APM 2.6

3M gps unit

A2212/13T motors

30A hobbypower (linear) ESC.

battery monitor


Zippy 3S 5000mah 20/30 C lipo

FlySky fs-th9x transmitter stock

I guess the weight is between 1500 to 1600 grams

I calibrated the ESCs, auto trimmed and  auto tuned the F450 on it's first flight and have not had any issues with it during the dozen flights it's been on,

The only issues I've encountered are that it wants to crash within a foot off the ground when lifting off from within 10yards from my house. I suspect thats due to the 3 2.4g access-points with high gain antenna I have running in the house.

On the last flight I flew, the quad crashed within 100 yards. it started flying as normal. I took off to about 20 feet and pitched forward quickly for about 50 yards and was in the process of pulling quick altitude to make sure I cleared the very tall trees. The quad started to climb and just stopped in mid air and leaned over like it might have broken a propeller. I've looked at the telemetry data and data log data from the apm but am not sure of the cause. The telemetry logs are saying -96 feet altitude  when it crashed but does not stated the quad has crashed.

Damage during the crash is as follows:

2 half broken props

1 fully broken prop

arm cracked at motor mount forcing motor to lean inward

telemetry popped out of it's case

GPS unit fell of the rod from the top of it's mast.

My gut feeling is that the GPS fell off and caused the crash, however from everything I've read STAB mode does not require GPS.

Before the crash I had decided to turn the F450 quad into a F550 hex because it would give me more redundancy if I have a motor/prop/esc failure, so I have a new frame, motors and escs on the way. I just want to make sure that there is not an electronics issue when I transfer the F450 parts to the F550.

I'm uploading the telemetry logs and data flash logs encase anyone wants to take a look and help me diagnose the problem. Telemetry for the crash flight starts about  74% .



2015-09-15 15-46-43.tlog

2015-09-15 15-53-10.log

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  • Thank you for taking the time to give me some pointers.

    I flew the Quad about an hour before the crash to a couple hundred feet and it flew and reacted as it should. So my guess is the servos were wired correctly. all the servo wires where completely seated so it had to be the GPS falling off it's mast that caused the crash.

    All the components from the F450 quad are now part of the new F550 and it has had a quick test flight to set auto trim. It flew pretty well except the flight time is down to a couple minutes of hover. I'm not sure how to determine what I'll need for a battery or batteries to get a decent flight time. It has a zippy 5000mah 20C now but at a couple minutes of flying battery failsafe kicks in and brings it home. The Failsafe setting is at 10.5 volts, 5000mah and a 600mah reserve I did notice that the battery voltage recovers to about 11.5 volts after the flight. The new F550 now has FPV and an analog 2 axis gimbal (pan/tilt). I'm not sure how much power the FPV components draw.

    Here's theFPV system I installed on the HEX.

  • the gps can cause the quad to crash if it comes loose,also chech servo leads are connected in correct connections as if one isnt connected corectly it cas cause a crash

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Shivchand Jaysaval liked Shivchand Jaysaval's profile
Aug 25