GENERAL AVIATION - CLIMBING

Transcription

1 GENERAL AVIATION - CLIMBING This tutorial follows on from the normal take off and will address climbing. The techniques described here are again generic in nature and may yield slightly different results depending on your particular sim setup and the make and model of aircraft you choose to fly. I have used the Carenado Piper Archer as the demonstration aircraft for this tutorial, it is a well proven trainer in real life and seems to possess very accurate flight characteristics in the sim. It is perhaps among the best GA trainers for teaching basic flight maneuvers and I recommend you grab one if you do not already have it in your hanger, you can of course also fly and practise these manoeuvers with the default Cessna. Carenado PA28 Archer There are several different types of climb, this lesson is aimed at a climb where your aircraft is setup for the best rate of climb. The speed for the best rate of climb is known as Vy. This is the speed you want to see on your ASI (airspeed indicator) that gives you the best rate, or if you like, the most height gained in the shortest length of time. For many light aircraft the best rate of climb (RoC) is usually placed somewhere around ft per minute (fpm) and is achieved by climbing at Vy. For our demo the best rate in the Piper Archer is 78KTS.

2 Different aircraft have different speeds, research any material that came with your software. You will have to know what is Vy for your aircraft. Other types of climb are the cruise climb and the best angle of climb, I will address these shortly in this tutorial. For now we will focus on the basic technique used to perform a standard climb. For climbing we use a basic pneumonic called P-A-T: P - POWER A - ATTITUDE T - TRIM P is for power and almost all light aircraft will use full power every time you need to climb. So apply maximum power just before you raise the nose. A is for attitude, by this we mean raising the nose to the climb attitude. You should raise the nose until your speed settles at the best rate of climb speed, hold this attitude and then commence trimming for that speed. T is for trim, once your speed reaches Vy you need to trim the aircraft to hold the climb attitude and keep that speed. Normally the trimming requires one or two turns of the trim wheel and then some small tweaks to get the speed almost spot on. It is almost like fine tuning a radio, you first find the station and then make small adjustments to find the sweet spot. If your aircraft is trimmed correctly you should be able to take your hands off the controls and it should keep climbing at Vy.

3 Also keep in mind the slip stream effect that I described in the normal take off tutorial, you will need to apply a small amount of right rudder when you apply full power and try and keep the ball centered on the turn co-ordinator. The slip stream effect is even more pronounced at full power during a climb. Now that you are established in the climb observe the VSI (vertical speed indicator) and check your climb rate, this will vary according different conditions such as, aircraft type and configuration, aircraft weight, density altitude, temperature, etc. Piper Archer during a climb Note the VSI indicating a climb and the ASI is set at Vy and the Turn Co-ordinator has the ball centered and the Altimeter indicates a climb. The AH shows an attitude of 10 degrees nose up which also seems to be the normal climb attitude for many lighties.

4 Also be sure to check your (T s and P s) or the temps and pressures ensuring they are all in the green. It seems many sim aircraft actually do simulate higher pressures involved with increased stress placed on the engine during a climb. The engine heats up since it now has reduced airflow and less cooling and not to mention the fact that it is working at its hardest. If the temp gauge gets a little on the high side, simply lower the nose a little and climb at a higher airspeed, this allows for better airflow and thus better cooling. Keep an Eye on the Temps and Pressures At the top of climb or what is known in the business as (ToC) you will need to lower the nose to adopt the cruise attitude. So when do you start lowering the nose? Usually at about 10% of your climb rate or let s say that you are climbing at 1000fpm, start dropping the nose at about 100ft before reaching your cruise. This should ensure a smooth transition from your climb to cruise and also make it easier to level off without over-shooting or under-shooting your cruise altitude. Very often people will try and chase the altitude and continually make reference to the VSI, the best way is to simply set the nose about a point on the horizon as shown below. Straight and Level Flight

5 The technique used at the ToC is also A-P-T: P - POWER A - ATTITUDE T - TRIM P is for power so now you need to reduce your power to the cruise RPM which is typically about 24RPM in most single engine fixed pitch general aviation aircraft. I usually leave the power at max RPM until just before reaching the cruise speed and then back it off. A is for attitude, so now you want to ease the nose down on the horizon and set the aircraft in a straight and level attitude to resume cruise flight. T is for trim and just as before when you have the aircraft set at the cruise attitude begin trimming for straight and level flight. In real aircraft you can release the controls and check to see that you have trimmed the aircraft properly, another thing to note when trimming for the cruise is to check the VSI as it should be reading zero or floating around the horizontal. Try practicing this manoeuver in an aircraft you know very well, you would be surprised how the basic stuff such as this will soon enough spill over to flying more advanced aircraft and at the same time enable you to develop good habits and make use of the correct flying technique. Funny enough when flying more advanced aircraft you would in some cases actually use the P-A-T technique where you pull first to set the nose attitude and then apply max power and then trim, this is o you do not overstress the airframe with an overspeed. In other circles some flying schools like to teach the P-A-S-T method whereby you set the power, attitude and then wait for the speed to settle and then trim the aircraft, this method is very effective when reaching the top of climb and commencing the level off. The correct technique is dependent upon the aircraft you fly and although many will be similar it is wise to consult the manufactures handbook for the specified procedures on aircraft handling.

6 I mentioned earlier about other types of climb, these are used for different circumstances and each warrants their own merit based on predefined conditions. The best angle of climb or (Vx) is generally used after a short field take off to clear obstacles at the departure end of the runway. The speed for Vx is usually much less than Vy and has a much higher climb angle than the standard climb. This kind of climb has the highest angle of all and is intended only as a transient manoeuver after which you would normally resume a standard climb. I will get into this topic further in the short filed take off tutorial. The cruise climb has the lowest angle of all and would generally be used for the best time performance since you end up having a faster ground speed than what is seen during a standard climb. Because this kind of climb has a lower angle of climb it does take a little longer to reach your cruise altitude, however the payoff is that you may arrive quicker at your destination due to a higher speed immediately after departure. In some circles this kind of climb is also known as the standard climb and many airliners use this type of climb as a compromise between fuel and OTP or on-time performance. Below details the different kinds of climb.

7 Abbreviations and Extras: VX VY - BEST ANGLE OF CLIMB - BEST RATE OF CLIMB ROC - RATE OF CLIMB TOP - TOP OF CLIMB ASI - AIRSPEED INDICATOR VSI - VERTICAL SPEED INDICATOR AH - ARTIFICIAL HORIZON FPM - FEET PER MINUTE RPM - REVS PER MINUTE OTP - ON-TIME PERFORMANCE T S AND P S TEMPS AND PRESSURES RULES: Power, apply maximum power as you raise the nose, apply full power, right rudder. Attitude first (raise the nose until at Vy) Trim off excessive control forces keeping the speed steady at Vy. Commence level off at about 10% of your climb rate. Hold the correct attitude at altitude, allow cruise speed to build and retrim the aircraft. By Steve Quinn

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