Helicopter Flight Information
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Helicopter Flight Information This domain is for sale. #1 in all relative searches, 12,000 views per month averaging 400 views per day! |
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Flying by NumbersMany students have trouble getting the results they are seeking, it is no wonder, they don't know where to start. It does not need to be this way, there is a simple concept to teach. Flying by numbers is nothing new, it is just not commonly taught except for instrument training. This process works in every aircraft, helicopter or airplane, and it is much easier to achieve the desired results when you have a starting point. I develop a number system for all aircraft that I fly and teach in, and it works every time. See Also Poor Flight Technique. Let me give you some examples: The Robinson R-22:
In this example, you can maintain the manifold pressure almost exactly at 18" and feather the cyclic for altitude. You will find that you will remain at or near 45 knots, and your altitude will be constant. If you enter an Air Taxi turn, you will need a 2" increase of manifold pressure to maintain the altitude and airspeed. When you roll out of the turn, you will need to again reduce the manifold pressure to 18". Try it, it works! The variation will be slight but you have a starting point. How much power should you use in your normal climb out profile? What ever it takes to hover. One factor that never changes no matter which model of helicopter you fly is the fact that if it will hover, it will fly with no further increase in power. When you pick the helicopter up into a hover, note the power applied (manifold pressure). This is also known as a power check. Unless you are flying at a high density altitude, you will be able to hover. The power applied in the hover should be your normal take-off and climb out power. If you are with an instructor (two people in the aircraft (R-22)), The power applied will be about 24". If you are solo, this power will be about 20". Does the helicopter sink slightly when you begin to accelerate into forward flight? If so, you are accelerating to aggressively. In most cases, the pilot will increase the collective at this stage, and in many cases an over-torque will result (R22 at max gross). Why does this sink occur? Remember that while in a hover, you are in ground effect. When you begin to move forward you have tilted the disk forward, therefore the lift vector has changed from down to some down and some forward (visualize the flow of air through the rotor). A slower more gradual acceleration forward will, in most cases, correct this situation (there are occasional cases where the collective must be used some to prevent ground contact, but never so much as to exceed power limitations). In any case, controlling altitude with the collective while accelerating forward is poor technique since the collective should remain relatively fixed. Remember also that in every stage of flight, there are two 'given or fixed' factors, and one 'variable' factor. This remains true, again, regardless of the aircraft being flown, fixed wing or helicopter. Additional examples (R-22) see NOTE below also: Acceleration from a hover to departure
Climb out profile
Cruise profile
Initial approach profile
Short-final approach profile
Autorotation
Pattern cruise
In each of the examples given above, you have a positive starting point. Of course you will have to adjust for current conditions, however it will be a minor adjustment. A similar example can be established for the R-44, Schweitzer, Bell 47, Jet Ranger etc. All helicopters (model specific) have a set of numbers that work consistently no matter how many different ones you try (same models) . Even moving into turbines this works as outlined for the Bell 206 below. The Robinson R44: Acceleration from a hover to departure
Climb out profile
Cruise profile
Initial approach profile
Final approach profile
Autorotation
Pattern cruise
I currently fly both Jet Ranger and Long Ranger models of the Bell 206, yet the same numbers will be close for both models even given their different size; see below: The Bell 206 Numbers: Acceleration from a hover to departure
Climb out profile
Cruise profile
Initial approach profile
Final approach profile
Autorotation
Pattern cruise
If you learn to fly by numbers, your training will be easier, and your learning curve will be shorter. Try practicing this style of flying and see if your precision is better. I am sure it will be. As always, if you have any questions, please feel free to contact me. I am aware that many instructors teach cross-country cruise at maximum manifold pressure as well as a faster pattern speed flown also at a higher manifold pressure, but what is the point? If you fly the pattern at a faster speed, you will be that much more jammed up at the most critical point. Just because the aircraft is capable of 24" of manifold pressure does not mean that you must pull it. My preference is moderation, it helps the learning process and it is also far safer. NOTE: When using the fly-by-numbers technique, you will be a better pilot however you must keep in mind that a given setting, say 21 inches manifold pressure, does not mean 21.5 nor 20 etc. You must be precise. The airspeeds and altitudes must also be precise. A 60-knot approach does not mean 58, this will hang the aircraft and you will be high on final. 60-65 knots means 60-65 knots. Enjoy your training, and fly safe!!
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