How do people take off from metal objects?

[AvatarWings]

So I hear people talking about how they are taking off from the roof or hood of their car. And I have also seen videos on YouTube of people taking off from steel barrels. How do they do this? Doesn't this mess up the compass? Does it give them errors before take-off but once they are far enough away from the metal object, the compass works fine?

I am ultra cautious and will not fly if I see any problems with the compass or IMU. I'm amazed that people are successfully doing this. Is this risky and should never be done? I am amazed that people can do this?

 

[dirkclod]

I can't my hood but do from my truck bed.If my app says all is good I do . Why you can I have no idea but have been doing it for years . It does not mess up my compass none.
If your app throws a error at you pay attention, trust your app .

 

[Top Hat]

I took off from my car sunroof with no problem.

 

[sar104]

So I hear people talking about how they are taking off from the roof or hood of their car. And I have also seen videos on YouTube of people taking off from steel barrels. How do they do this? Doesn't this mess up the compass? Does it give them errors before take-off but once they are far enough away from the metal object, the compass works fine?

I am ultra cautious and will not fly if I see any problems with the compass or IMU. I'm amazed that people are successfully doing this. Is this risky and should never be done? How are they getting away with this?

If the surface, or something under the surface, is magnetized then the compass will produce an incorrect reading. And if that happens, unfortunately, the problem doesn't go away after takeoff. Stable flight requires the IMU yaw to be initialized correctly by the compass data before takeoff - if it isn't then the primary yaw value in flight will start out incorrect. After takeoff the compass will likely start to read correctly, but now the IMU yaw, derived primarily from the rate gyros, will significantly disagree with the compass and with reality. The aircraft will either switch to ATTI mode (best outcome) or, if it stays in P-GPS while attempting to rotate and resolve the discrepancy, may enter uncontrolled linear or toilet bowl flight.

 

[EyeFlightDrone]

Hand launch!

 

[SteveCA]

+1 for hand launch

 

[AvatarWings]

I can't my hood but do from my truck bed.If my app says all is good I do . Why you can I have no idea but have been doing it for years . It does not mess up my compass none.
If your app throws a error at you pay attention, trust your app .

When launching from your truck bed, do you get compass or magnetic interference errors prior to taking off?

 

[Fplvert]

+1 for hand launch

Difficult with a Phantom, but easy with a Mavic!

One thing that hasn’t changed is I like to hand catch as well, as the Phantoms like to tip, and the Mavic likes to mow grass.

 

[DanMan32]

Phantoms won't tip if you grab the vertical struts. They definitely will if you grab the bottom horizontal struts.

 

[Fplvert]

When launching from your truck bed, do you get compass or magnetic interference errors prior to taking off?

Dirk probably does this just to get an ATTI experience. He’s been flying these things for years. He starting with his kit in a paper sack on the floorboard.
Don’t try this unless you are ready for a heart attack.

 

[dirkclod]

 

[dirkclod]

When launching from your truck bed, do you get compass or magnetic interference errors prior to taking off?

No nothing the Go App shows all good and says go.