HOME | ABOUT | FORUM | FILES | ARTICLES | MULTIPLAYER | TRAINING | FAQ | GALLERY
Terms of use • Privacy statement  
 

Home Page > All Articles > Helicopter Training > Helicopter Autorotations done right!


ARTICLE CATEGORIES

 All Recent Articles
 Hovercontrol News
 Flight Simulator Enjoyment
 Flight Simulator Setup
 Hovercontrol Training
 Flightsim Development
 Multiplayer Setup
 Multiplayer Events



   
Helicopter Autorotations done right!

Bookmark and Share
• Print Article        

It’s one of those mornings just made for flying. Clear sky, visibility better than 20 and moderate winds. You’re flying along in your Jet Ranger and all is right with the world. THEN… for whatever reason… your faithful C20J decides to call it a day and your annunciator panel starts blinking like the Vegas Strip. Now, without some decisive action on your part your helo will assume the glide ratio of an anvil and you will have a very bad day. Since you can’t exactly pull over and call AAA, you NEED to know how to auto.

Autorotations are a part of every real-world pilot’s training. Autorotation is basically an exercise in energy management relying on conserving the potential (stored) energy in the spinning rotor to cushion your touchdown. You also have to wisely use your altitude and airspeed to achieve a controlled landing in a safe spot.

The Setup:

If at all possible, always land into the wind. It allows a lower touchdown speed while still having effective translational lift further cushioning your touchdown. It also enhances directional control just before touchdown. For practice, set up your own winds, moderate 15 to 18 knots, and to the same heading as your selected runway. Also set up a good outside view because it will be necessary to maintain a good sight line of your landing area. You can shrink the default panel to a size that improves outside view, but still readable, or disable it and use a HUD, preferably one that shows rotor rpm, airspeed, and AGL. I used one from Hovercontrol’s own Steve “SkyMed” Hanley. You can also use a top-down view to help you in the pattern, but keep it small to maximize your outside visual cues.


In a full-on auto you will use Ctrl+F1 because it will essentially kill all power to the engine. In flight, we won’t use the fuel flow switch to shut the engine down. In real life, doing so would cause the burner section of the turbine to drop from 700 to 800°F to ambient almost immediately, severely damaging the engine. The collective has a motorcycle-like twist throttle that controls engine rpm. Ctrl+F1 rolls off the throttle, so that is what we’ll use for practice. Ctrl+F4 will bring it back up. You may want to setup a joystick button for this (these) function(s).


The Procedure:

Fly a standard pattern, 500 AGL and 80-100 knot airspeed. Line up on short final for the desired runway, check that it’s clear, and within your glide range. Press Ctrl+F1 (or the previously mentioned joystick button) to roll off the throttle and smoothly, but quickly, lower the collective fully.Here’s where we run into a glitch in FS2004, immediately after lowering the collective you have to bring in about 10-20 % up collective otherwise for some odd reason the rotor rpm will quickly degrade and will be unrecoverable. This is totally unrealistic, but is the only way to make it work in FS2004.


Short final... throttle closed...60 knots



Doing so will maintain the rotor rpm at the 100% necessary for proper autorotation. …IMPORTANT… Anytime you allow your rpm to drop below about 80% you are most likely going to become a smoking hole… Once you have your 100% rotor rpm, you will use cyclic to trade off altitude for airspeed maintaining 60 knots. If you’re going too fast maintain altitude, while turning base, till the speed bleeds off and then ease the cyclic forward to glide toward the runway using cyclic to maintain alignment. Maintain this attitude till 50 to 100 ft AGL then commence a gentle flare, gradually increasing the pitch up as you descend, to bleed off speed.


Flare at 50 ft...50 knots...slowing the helo




Outside view 34 ft AGL



At 20 to 30 ft AGL,add a bit of collective and level the aircraft. Maintain this attitude with cyclic and at 10 ft AGL smoothly add collective using the remaining rotor rpm to cushion the landing.


Skids level 5 ft AGL... cushion with collective and allow to settle



Too quick on the collective and you can balloon up, lose your remaining rpm, and drop out of the sky. Keep it straight with the pedals in case you still have a bit of forward speed upon contact (remember that if you have Realism set for indicated airspeed your ground speed will be 16 knots slower at present wind settings). This way you can slide it on without risking a rollover. They call them skids for a reason. Better to have to replace the skid shoes than the helo. As you improve, you should be able to shorten the run out to 1 or 2 skid lengths.

Consistency pays:

During practice, always enter your autos from the same altitude, airspeed, and start point (a specific ground reference feature helps). This repeatability will allow you to get a better understanding of the procedure and allow you to judge your landing point better. Once you get that part down, you can change any one aspect to see what impact it plays on the glide performance. Also, you can extend on the downwind leg so you have plenty of time to establish a solid airspeed and altitude before you enter the auto.

Juggling the variables:

Now try mixing it up. Use the same altitude and entry point but fly the auto at 52 knots. What did you find? You should have actually had more time aloft but less distance over the ground, great when you’re almost directly over your desired landing spot. 52 knots is your minimum sink rate speed.

Off airport landing...see the barn....and TREES... that's your site...ready to close throttle?


Made it !!!!


Need a longer glide to clear an obstacle or reach a better site? Use your best glide ratio speed, 69 knots. With a 4:1 ratio, you should have traveled a significantly longer distance over the ground and hopefully dodged that big rock. If you think you may overshoot even with the minimum descent speed you can always use a series of S-turns given sufficient altitude. Even with the variables, it’s always desirable to land into the wind.

Autorotation with a 180-degree turn:

Sometimes you just passed a suitable site when the engine sputters. It’s possible to do a 180 autorotation to a safe landing. You can try this exercise at both 500 and 1000 AGL. To practice, run a pattern with longer departure leg and a shorter crosswind, so your downwind leg is close to the runway. Your downwind leg should be no further than ½ your altitude away from the desired runway. When approximately ¾ to the desired runway’s threshold, on the downwind leg, pull the plug. Don’t wait till you have 60 knots to turn base and don’t bleed off too much speed in the turns. Use the pedals only to maintain coordinated flight and not to turn the helo. Slips or skids will eat up precious airspeed and altitude and increase your sink rate. The downwind-to-base, and base-to-final turns can actually be one turn as long as it sets you up properly for final. Once established, you can adjust to the best auto speed for desired landing spot and treat it like a straight–in auto.

According to my mentor, Gazoo, “The best part of learning is when you are able to learn by yourself.”
So this is where I cut you loose. Practice, practice, practice. Once you feel competent in the 206, try other helos. Try off airport autos, different winds, altitudes, and elevations. Remember, in off airport autos, to pick a likely site and then use the appropriate pattern procedure to reach it, just like practice. Work at it until you feel as comfortable with the engine out as on. Practice till autos are automatic.

Autos are addictive. If you find yourself succumbing to the disease you can always try the Schweizer, things happen really fast in that little bird and the technique is kinda weird. It is lot like finding yourself in a phone booth with a cougar, but even they’re survivable with enough practice. Good Luck.


Come to think of it that cougar has to be easier to tame....Here kitty kitty



I would like to thank Gazoo for the great autorotation session which in large part is the basis of this article. Also thanks to my pal SkyMed for his HUD and initial auto instruction on the 206, I would have never figured out the collective glitch. I’m not sure if I want to thank HC_4 Keith, or not, because he got me started autoing the Schweizer. I guess I will anyway, in spite of the fact that I spent 3 hours getting something survivable. Thanks alot Keith I really appreciated the help.




Practice pays!!! ...This one's for you Keith.








COPYRIGHT 2011 - HOVERCONTROL.COM - ALL RIGHTS RESERVED