VRS

[snowghost]

I just got my P4 but was reading about the pretty quick descent rate in Sports Mode. Has anybody experienced VRS with its higher drop rate?

 

[sar104]

I've been wondering about that too. My P2s go into VRS at the drop of a hat up at 7500 ft. The P4 feels much more stable descending, but I'd rather not find out the hard way and have to take evasive action.

 

[JRvV]

When bringing my P4P down, I have noticed it wobble a bit. I'm not sure if it would stall if I didn't do anything about it, but I'd not want to find out. Simply introducing a little forward or spiral movement fixes it.

 

[Mimoid]

VRS (propeller tip vortices) should be nearly impossible to encounter with the P4 as the motors are slightly slanted outwards to avoid creating standing waves. Nonetheless, I almost never descend straight down but always perform some kind of approach pattern - unless I am in a limited space, like between trees.

 

[N017RW]

VRS (propeller tip vortices) should be nearly impossible to encounter with the P4 as the motors are slightly slanted outwards to avoid creating standing waves. Nonetheless, I almost never descend straight down but always perform some kind of approach pattern - unless I am in a limited space, like between trees.

Standing waves is not the proper analogy as that requires reflectance. In free-space there is none.

It’s more about descending into a descending column of air. It snowballs as you add more power to overcome which actually exacerbates the problem. (i.e. Settling with Power)

But yes, the outward thrust vector created by canting the motors reduces the tendency for the air column to form, not to prevent standing waves.

 

[Mimoid]

Standing waves is not the proper analogy as that requires reflectance. In free-space there is none.

It’s more about descending into a descending column of air. It snowballs as you add more power to overcome which actually exacerbates the problem. (i.e. Settling with Power)

But yes, the outward thrust vector created by canting the motors reduces the tendency for the air column to form, not to prevent standing waves.

Yes you are right, that was a poor analogy, thanks for correcting.

 

[N017RW]

Yes you are right, that was a poor analogy, thanks for correcting.

All good. Thanks for your input!!

 

[David Kraft]

Standing waves is not the proper analogy as that requires reflectance. In free-space there is none.

It’s more about descending into a descending column of air. It snowballs as you add more power to overcome which actually exacerbates the problem. (i.e. Settling with Power)

But yes, the outward thrust vector created by canting the motors reduces the tendency for the air column to form, not to prevent standing waves.

Well in a compressible medium you can experience standing waves.

 

[N017RW]

Absolutely, provided there is a reflected wave of correct amplitude and period or frequency.