Comfort zone for main rotor clearance

[mickjoebill]

Following recent prangs involving aerial filming some friends on a camera forum are trying to get a handle on the industry minimums for rotor clearance.


What is your comfort zone for the minimum clearance of main and tail rotor for private, filming or medevac work?
Lets say a) for landing, b) for manoeuvring (with a recce)



Mickjoebill

[fly911]

In my early days of helo flying, when my comfort zone was quite a bit greater than my instructors', he landed very close to the fuel station vent pipe. I got out and fueled the Hiller UH-12E and got back in. He said "You've got it". When I lifted off, I nearly rolled it over with so much cyclic away from the vent pipe so as not to drift toward it, that the instructor had it take the controls in order to avoid dynamic rollover. Now thousands of hours and many years later, I recently put another pilot in a situation beyond his comfort level and had to intervene. Live and re-learn.

[Fareastdriver]

Half span; one full rotor blade clearance. Anything closer than that you are in the worry zone.
You are not paid to be there unless you are in a war or saving somebody's life.

[Al-bert]

when you see grass and daises being sucked out of the ground (cliff top), that's too close! :E

[SASless]

Depends on many factors....wind, turbulence, visual cues, day...night...rain on the Windscreen, the aircraft, my performance level that day.

General rule....half a rotor disc for what I can see.....a full disc-to two disc's from what I cannot see.

[[email protected]]

Sas - I agree with your general principles other than how you can judge clearances from something you cannot see;)

[alouette3]

I am assuming everyone here is talking about Main Rotor Spans/Discs and not Tail Rotor Spans??;)
Alt3.

[ShyTorque]

General rule....half a rotor disc for what I can see.....a full disc-to two disc's from what I cannot see.

Sounds good to me. I was once sent landing instructions and a blurred photo of the "helipad" at a hotel.

When I got there, the vis wasn't good due to heavy rain and the LS was smaller than I thought from info given. I decided to move as far forwards as I could, towards the main building, to ensure I gave plenty of clearance behind me for the tail, i.e. put it over the H. After the passengers had gone I did my usual walk round and discovered what I thought was the official marked "H" was an H shaped shrub bed and the tail rotor had chewed some twigs off the side of a three foot high weeping willow bush growing out of it. :O

[mickjoebill]

Thank you gentlemen.


Mickjoebill

[fly911]

When hovering near a wall, be carefull not to get too close. The downflow on the wall side of the rotor disk has no place to escape and recirculates through the rotordisk causing a loss of lift and drawing the ship into the wall. It happened to me only once, and it took abrupt action to recover. I won't put a distance on it because it may vary with wind, etc.