Try Flying by Numbers, it works and you get results...
Many students have trouble getting the results they are seeking, and it's no wonder; they don't know where to start. It just doesn’t need to be that hard; 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. Let me give you some examples (this one in the The Robinson R-22:
Air Taxi - Target = 45 knots @ 50 ft. AGL
- Initiate climb using a normal departure to a steep climb profile at 45 ft. AGL then begin forward cyclic input
- Establish forward acceleration and when passing 40-knots reduce manifold pressure to 18 while establishing a level flight attitude.
- Feather the collective for airspeed and the cyclic for altitude. This will give you level flight at about 50 ft. AGL, at or near 45 knots.
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? Whatever 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 or torque). 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. 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), you blow your ground effect rearward. A slower more gradual acceleration forward will, in most cases, correct this situation and exhibit pilot skill and knowledge (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, regardless of the aircraft being flown, fixed wing or helicopter. Additional examples (R-22) see NOTE below also:
Acceleration from a hover to departure
- Given power setting (hover power)
- Fixed rate of climb
- Variable airspeed (accelerating)
Climb out profile
- Given power setting
- Given airspeed (60-knots)
- Variable rate of climb
Cruise profile
- Given power setting (21-22" - pilot selection)
- Given altitude (pilot choice)
- Variable airspeed
Initial approach profile
- Given power setting (15-17") Pilot's choice
- Given airspeed (60 knots)
- Variable sink rate (will be almost exactly 500 fpm)
Short-final approach profile
- Given power setting (13")
- Airspeed steady rate of decrease
- Decreasing sink rate (to less than 300 fpm)
Autorotation
- Collective to maintain desired rpm (first stabilized at 100 percent, then adjust for desired profile)
- Given airspeed (stabilized at 60-knots then adjusted for desired profile)
- Variable sink rate
Pattern cruise
- Given power setting (19-21") Pilot's choice
- Given altitude
- Variable airspeed (about 60 knots)
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
- Given power setting (hover power)
- Fixed rate of climb
- Variable airspeed (accelerating)
Climb out profile
- Given power setting
- Given airspeed (60 knots)
- Variable rate of climb
Cruise profile
- Given power setting (21-22" - pilot selection)
- Given altitude (pilot choice)
- Variable airspeed will be at or near 100-knots
Initial approach profile
- Given power setting (13")
- Given airspeed (60-65 knots)
- Variable sink rate (will be almost exactly 500 fpm)
Final approach profile
- Given power setting (12")
- Airspeed steady rate of decrease
- Decreasing sink rate (to less than 300 fpm)
Autorotation
- Collective to maintain desired rpm (first stabilized at 100 percent, then adjust for desired profile)
- Given airspeed (stabilized at 70-knots then adjusted for desired profile)
- Variable sink rate
Pattern cruise
- Given power setting (18")
- Given altitude
- Variable airspeed (about 75-knots)
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
- Given power setting (hover power)
- Fixed rate of climb
- Variable airspeed (accelerating)
Climb out profile
- Given power setting (80% torque)
- Given airspeed (60-knots)
- Variable rate of climb
Cruise profile
- Given power setting (80% torque)
- Given altitude (pilot choice)
- Variable airspeed (will be about 115 knots)
Initial approach profile
- Given power setting (30% torque)
- Given airspeed (60 knots)
- Variable sink rate (will be about 500 fpm)
Final approach profile
- Given power setting (20% torque)
- Airspeed steady rate of decrease
- Decreasing sink rate (to less than 300 fpm)
Autorotation
- Collective to maintain desired rpm (first stabilized at 100 percent, then adjust for desired profile)
- Given airspeed (stabilized at 60-knots then adjusted for desired profile)
- Variable sink rate
Pattern cruise
- Given power setting (50% torque)
- Given altitude
- Variable airspeed (about 80 knots)
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.
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? 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. Remember that the greater the angle of attack (higher power setting), the greater the rate of rotor decay in the event of an engine failure.
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 knots means 60 knots.
Enjoy your training, and fly safe!! Jump to Top