Crash at 13,000 feet

[BlackHawk388]

No. I didn't realize how old this thread was before I posted my comments above.

Thread age kicks my butt again. *sigh*

 

[mad in nc]

might have been an old thread but you revived it with a great response!

 

[BlackHawk388]

might have been an old thread but you revived it with a great response!

Thank you for your kind remarks.

Being new here, I'm reading a lot of threads and this one caught my attention as not having a likely explanation for the crash. Any real world experience I can contribute to this diverse community is well worth my time. If I can help even one R/C pilot to prevent a crash, it is time well spent IMO.

 

[Tom Donnelly]

It is a fact that high altitude has an adverse effect on performance. The air is much thinner - at 13000 feet it is only about 60% of the density at sea level. At some altitude you wouldn't have been able to fly at all. Obviously you were able to fly but it would take a much larger percentage of your available power than at sea level. You would have had much less performance left for maneuvering. A quad uses that remaining power to control stability and to maneuver. You may have just run out of maneuver margin. A slight down slope wind could easily be greater than you could over come.

I think you should re confirm your 60% number.

 

[BlackHawk388]

I think you should re confirm your 60% number.

I would tend to agree. Since this drone isn't a turbine or reciprocating aircraft dependent upon air intake to an engine to mix with fuel to create combustion and then, power, this "rule of thumb" doesn't quite apply.

One could say that electrically driven motor(s) depend on temperature to remain effective. This is true. However, at this altitude, the ambient temperature will affect the battery MUCH more so than the motor(s). Indeed, the motors will remain cooler at such altitude and thus, they will be more efficient in their use of electrical power.

Sure, thinner air means less lift no matter the propulsion method. However, it is a proven fact that electrically driven craft can fly higher with less power required of the engine(s)/motor(s) given the same environment as a combustion engine.

There are many factors that come into play here. Temperature affects battery powered craft in a completely different way than a combustion engine. Typically, the lower the temperature, the more oxygen molecules available for internal combustion at altitudes low enough to ensure combustion efficiency. Meanwhile, batteries of all types show a reduction in available amps over time in a much colder environment.

I'm sure some scientist has made a graph that shows the transitional phases of where internal combustion engines outperforms the power and longevity of flight offered by electrically driven motor(s). For R/C aircraft, I've found that high altitude flight is tremendously better given an electrically driven craft over combustion even with the shortened lifespan of a given battery cell due to low temps.

 

[Tom Donnelly]

You know, got to thinking about some these mysterious fly aways. Is it possible that a pilot could inadvertently get into the position where the iPad is blocking the radio aerial line of sight. Looks possible to me especially if the drone flew over your shoulder.

Anyway just a thought.

 

[MapMaker53]

You know, got to thinking about some these mysterious fly aways. Is it possible that a pilot could inadvertently get into the position where the iPad is blocking the radio aerial line of sight.

I'm sure that's possible for a tablet to block the antenna signal, as I often find myself not facing my P2V+ when I get absorbed in the tablet view and momentarily lose track of where it is in the sky. But such a signal loss would automatically invoke RTH, not a flyaway.