Yesterday I touched on the theory of the different kinds of climbs.\u00a0 I discussed the best-rate of climb (Vy) and the best-angle of climb (Vx).\u00a0 Today, let\u2019s talk about how we use the appropriate climb speed for given situations.<\/p>\n
Most of the time, we operate airplanes off adequate runways.\u00a0 By this, what I mean is, most pilots perform takeoffs on hard surface runways of more than adequate length without obstacles.\u00a0 The pilot\u2019s concern following this sort of takeoff is getting the airplane to the proper cruising altitude as soon as possible.\u00a0 To do this, a pilot should use a Vy climb or a cruise climb, depending on cruise level winds aloft.<\/p>\n
To explain further, if the flight plan calls for a tailwind enroute to the destination, most pilots want to take advantage of that wind.\u00a0 Typically, the winds aloft are stronger at altitude; it is to anyone\u2019s best advantage to spend as much time as possible in those high tailwinds at cruise level.<\/p>\n
The best way to do this is to climb the airplane into those tailwinds as quickly as possible.\u00a0 The climb speed for this is Vy.\u00a0 Again, this speed most effectively uses all available excess horsepower and provides for the fastest climb to altitude.<\/p>\n
On the return trip when the pilot has to deal with a headwind, the trick is to keep out of the high winds as much as possible.\u00a0 More than likely the flight plan will require a much a lower altitude where the winds are not as strong.\u00a0 However, the pilot is still dealing with a headwind component.\u00a0 The less time spent with a headwind, the better.\u00a0 This is where the \u201ccruise climb\u201d is most appropriate for climbing to altitude.<\/p>\n
There are two advantages to using a cruise climb when dealing with a headwind.\u00a0 First, the higher airspeed used in the cruise climb will allow for a greater distance traveled during the climb.\u00a0 Secondly, the pilot will reach altitude further downrange from takeoff.\u00a0 This allows for less time spent cruising against the headwind.<\/p>\n
The proper use of the third type of climb, Vx, is to clear obstacles. \u00a0Typically, this means getting beyond the 50-foot tree at the end of each runway as mandated by the FAA.\u00a0 However, all joking aside, in mountainous terrain you may have to use a Vx climb for an extended time to get over a nearby ridge.<\/p>\n
In clearing an immediate obstacle at the airport, the appropriate method is to keep the angle-of-attack on the wing reduced during the initial takeoff roll.\u00a0 This allows a faster acceleration on the aircraft due to the reduced drag of the lower angle-of-attack as opposed to the drag created by the higher angle-of-attack of a normal takeoff.<\/p>\n
Once the airspeed reaches a few knots less than Vx, the pilot then rotates the airplane to an attitude that results in a steady Vx airspeed.\u00a0 The pilot needs to consider two aspects of this climb.\u00a0 The first and most important is to avoid over-rotating; if he or she brings the nose too far up, the airspeed will be considerably low.\u00a0 An overly aggressive pilot may even pitch the airplane into a stall less than 100 feet above the surface.<\/p>\n
The other consideration for performing this takeoff is not being aggressive enough.\u00a0 In other words, if a pilot fails to pitch appropriately in the climb to avoid the tree at the end of the runway, the pilot might just fly the airplane into the tree.<\/p>\n
Stalling out 100 feet above the ground or flying into the tree is unacceptable.<\/p>\n
This is what makes the short field takeoff so challenging.\u00a0 Of course as I mentioned in the second paragraph, most of us today perform our takeoffs from hard surface runways of more than adequate length.\u00a0 Indeed, most pilots today shy away from any runway less than 2000 feet long.<\/p>\n
There are a few grass runways less than 1500 feet long scattered throughout the land.\u00a0 These are the airports I enjoy the most.<\/p>\n
-30-<\/p>\n
\u00a9 2011 J. Clark<\/em><\/p>\n","protected":false},"excerpt":{"rendered":" Yesterday I touched on the theory of the different kinds of climbs.\u00a0 I discussed the best-rate of climb (Vy) and the best-angle of climb (Vx).\u00a0 Today, let\u2019s talk about how we use the appropriate climb speed for given situations. Most … Continue reading