Tips on performing a vertical reference landingVertical reference
Posted 18 October 2018 - 18:28
Posted 19 October 2018 - 13:34
Posted 19 October 2018 - 19:34
Im struggling to understand the tendencies of the helicopter when on the air cushion or a few inches above the ground.
Any tips tricks to help me figure this thing out? I.e. I fly a 206L thanks in advance guys
The aerodynamic forces include main/tail rotor thrust, rotor downwash, wind, rotor vortex, ground effect and its interactions with the airframe, tail boom, and tail rotor. The inertia forces are these mainly related to the aircrafts mass, rotor inertia, and centrifugal forces. Inertia forces effect rotor response, pitch and roll rates, pitch and roll acceleration, yaw rates, and yaw-roll coupling.
These characteristics and dynamics mean you must constantly make small control inputs to maintain hover position over a given point. The idea of holding a hover is a misnomer, the fact being no one control position or setting would maintain a given position over the ground. In developing the ability to hover, you must learn to anticipate the motion and put in just enough control without overreacting. This is all complicated by the helicopters failure to react instantaneously to control inputs.
There’s a time lag between control input and the maximum aircraft movement. This is due directly to the magnitude of the control moment caused by flapping that always leads fuselage movement. The control moment also being a function both of the height of the rotor above the center of gravity and the distance the flapping hinges are offset from the center of the hub. Example, why some find the MD-500 (articulated rotor) easier to longline from vs. The Bell 206B/L (semirigid rotor), often called the "Wobble Ranger."
If you’re impatient, too much control input will result in overshoot and over correction. That, coupled with the normal instability and the need to control altitude and heading at the same time, soon gets you in an unwanted oscillation. Because of the time it takes for messages to go from the eye to the brain to the hand, you’re now doing the wrong thing at the wrong time, pilot induced oscillation.
Eventually you’ll puts all this together and can hover over a spot and land with precision under almost any condition, in any helicopter. Based on practice and experience, you should learn to analyze and resolve the inherent instabilities of a hovering helicopter and push through it and allow the helicopter to continue settling to the ground.
Remember, you’re in a totally different seating position than you’re used to; you’re actually up on your backside and you’re twisting your whole body so you can lean out and look down. You’re going to have to develop a comfort-level leaning out and looking down. Your hands and both feet will not be in their normal position, you’re going to have to deal with that too. Constantly think to yourself, “relaxed hands and relaxed feet make everything meek.”
You should start at a 6’ hover, leaning out and looking down, hold the ship’s skid over a given reference line on the ground and then move down from there incrementally. You’ll eventually get it down to 1 foot. When you can hold a hover there, then move on to actually trying to land.
There’s more inertia and stability about the longitudinal axis as opposed to the lateral axis; therefore, you should always try to move to your initial spot with forward cyclic then down, thus avoiding any tendencies to overcontrol in the lateral direction. Also be aware of the tail-low lift-skid-low attitude common to Bell two-bladed helicopters (see photo below) and the ship’s hook position which is aft of you seat position, requiring you to look down and a bit aft.
Again, you’re trying to develop a comfort-level leaning out and looking down. In the case of the Bell 206L (right-seat), you’ll be leaning out, looking down, and back. In the beginning a lot of students cheat by barely looking over their shoulder. Don’t cheat on the lean out. You’ve got to develop that comfort-level. Especially helpful if you ever end up slinging from an AStar (right-seat) where you sitting farther inboard from the door opening and farther forward from the hook position, reaching left for the collective hinged off the cabin floor.
The old school way made you do all landings and takeoffs, leaning out and looking down at the ground. Working in the bubble (bubble window) or doors off. Until you could do that consistently, no need attaching any line. That's assuming you're doing all this as an introduction into longline work.
Edited by iChris, 19 October 2018 - 22:12.
- Wally and Weads like this
Posted 20 October 2018 - 00:46
Exhale as you lower the collective and/or aft cyclic...even if it's the end of the rep when lifting weights, or depressing the trigger as you fire off a precision shot... (examples)
Make sure you're controlling your breathing at that critical moment, a nice controlled exhale always helped myself and the other voices in my head.
Edited by takefootoff, 20 October 2018 - 00:50.
- WolftalonID likes this
Posted 20 October 2018 - 01:29
Reasons like this.
Appears to be one of those companies that just completed a congested area Part 133 lift job at a city Mall/Shopping Center with a restricted category Huey. Commonly trailered in like that to under-cut their competition with lower bids by cutting ferry cost.
Also a way to get around §91.313[e] without obtaining a waiver under §91.905 to operate a restricted category aircraft over a densely populated area. They trailer it into the mid of the city, cordon-off the Mall/Shopping Center, declare it a non-congested area, do the lift, then trailer out of the city. Kill two birds with one stone, cut cost and regulations.
Edited by iChris, 20 October 2018 - 01:38.
Posted 20 October 2018 - 08:38
Edited by Fred0311, 20 October 2018 - 08:41.
- Wally and WolftalonID like this
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