Definitions - LTE
 

Is there a big problem with definitions of terms in helicopter pilotage?

There seem to be different phenomena in people's minds which are labelled LTE.

As a result people talk at crossed purposes and the wrong advice is given and efficient solutions are not discussed or missed.

I propose a series of posts labelled:
Definitions - LTE
Definitions - Autoroation (ie. just a state of flight, not EOL and not an emergency and not requiring rapid control changes / entry etc)
Definitions - Vortex Ring State (Fully developed - recoverable? - calm and stable?)
Definitions - Settling with Power (US definition - Vortex Ring but covers insuffiecient power on transition to hover (OGE)?)
Definitions - Translating Tendancy ... etc.
Definitions - Flapping
The aim being to reach coherant industry wide better/common understanding.....

Here's a stab at it:

LTE
Phenomenon 1
Lack of Tailrotor Effectiveness
Classically ment to indicate that the tail rotor provides insufficient thrust to counter the Torque of main rotor drive at Low (Zero) Airspeed (hover) - generally by (inadequate) design. Often found in old fashioned helicopters. This will lead to a rate of yaw which will continue unless the power (M/R torque) is reduced.
Insufficient thrust may arise for a number of reasons:
The tail rotor is feeble in design.
The RPM is too low - Still high torque to M/R but insufficient counter-torque.
High Altitude - ineffective T/R
Excess power applied to M/R - more than permitted.
Dirty T/R - temporary interferance with the efficiency of T/R (ice, dirt, plastic bags etc.)


Phenomenon 2
Loss of Tailrotor Effectiveness
Normally transient;
M/R vortex interferance - generally at low Airspeed (often hover)
T/R vortex ring - with relative airflow opposing T/R outflow. - This can result in massive unpredictable Loss of T/R Thrust - and can be self-perpetuating.
Weather-cocking - T/R insufficiently powerful to overcome Vertical tail surfaces - when flying with Relative Airflow not on the nose - self correcting.
Often because the T/R does not have enought Thrust to maintain yaw at high lateral airspeeds.


Phenomenon 3
Lack of Tailrotor Education.
Frequent amongst inexperienced pilots. (eg R44 ENG in Australia, EC130 in USA, Gazelle in North of England)
Yaw changes (sometimes rapidly) when unexpected - (timid) corrective action fails and control is lost.
Failure often wrongly presumed - so innapropriate pilot response.
Often as a result of not appreciating the Relative Airflow direction (negative airflow - weathercocking).
Often triggered by Phenomenon 2
Either firm response is required to prevent it - or no response would generally be ok since the Helli will align itself with the Relative Airflow if permitted.

Phenomenon 4
Lack of Tail Rotor
Not really part of LTE - but it is ineffective in cases of failure of drive, control mechanism, limitted Pedal travel etc...


Any good? Any use? Helpfull? Wrong? Thoughts?

Tail Rotor Education
 

Phenomenon 3 and Phenomenon 3 dont make sense to me

but maybe someone can explain the critical wind azimuth here really good coming from the good old B206 with the older tailrotor design.
I have an idea - but nowhere could i find a clear sense making explanation.

thanks h

LTE - Lack of Training & Experience.

Yup
 

Search this forum for threads by Nick Lappos. He explains the misconceptions clearly.