cw4ogden

That's what I assumed.
We have no such definition.
You probably want to see a graph of the forward speed versus vertical speed at which the helicopter enters the vortex ring?
There is no such.
It will be interesting for me to do this.

sorry for long reply:
 

For the US, it is the same we have no aircraft specific charts, only a very generic chart, for all aircraft.  
 

The reason I reference ETL is at some point in forward flight, the rotor is free of all vortices.

every pass of each blade is getting clean air.  This is why in cruise flight, you cannot get into the VRS, even if you put the collective all the way down.

The VRS requires vortexes, Which will be washed away beyond a certain airspeed associated with the term we call a ETL

all MI8 manuals I have seen say the susceptibility range starts at 40 Kmph.  That is a reasonable number.  It is around ETL airspeed.
 

What I’m saying is you can’t have a vortex ring related problem, when you have no vortexes, which is also the definition of being through effective translational lift. 

so they cannot coexist.

One is a Vortx phenomenon.  The other is an air speed range defined solely by saying it is speed at which you will no longer have vortexes.

it is impossible for both to be true, Because the definition of ETL is no more vortexes due to forward velocity.

We can debate the airspeed at which ETL happens, but we should not be debating whether or not you can get into VRS above ETL because ETL is by its very definition when you are no longer susceptible to VRS.

It is the forward air speed when the rotor is no longer ingesting vortexes.  that is my point, you cannot get into VRS below ETL, Because by the very definition of ETL then, if you are still experiencing vortexes, you are not above ETL..  It’s what defines ETL. 
 

Which would just leave us asking the question is the ETL airspeed modeled correctly?
 

One or the other has to be wrong, or our testing data from has to be wrong or explained by different aerodynamics than VRS.

I know that’s a lot of words to say a little, but you can’t have an aerodynamic phenomenon occurring in an area / airspeed that is defined by not being subject to that aerodynamic phenomenon.

VRS is off, or the ETL airsieed is off, or the mi-8 goes through ETL at a much higher airsieed than most helicopters.  And higher than the mi-8 operators manual says.  
 

Any of those are possibilities to answer what our data shows.  
 

But something seems off somewhere, and it’s manifesting in an abnormal VRS behavior.