A great short field take-off
HOW TO MAKE A GREAT SHORT FIELD TAKEOFF
Taking off from a short runway? Does your runway have trees or buildings at the end of it? Then it’s time for you to dust your short-field takeoff skills. Here’s how you’ll do it.
HOW SHORT FIELD TAKEOFFS ARE DIFFERENT
How does a short field takeoff differ from a normal one? It starts by creating a short ground roll, and then climbing at the best angle you can to clear obstacles (vx).
Why? By keeping your ground roll short, you don’t use as much runway. And by climbing at vx, you more easily clear obstacles beyond the runway.
So what are the steps of a good (or great) short field takeoff? We’ll break it down into three phases: takeoff roll, liftoff, and initial climb.
The first step in a successful short field takeoff is configuring your airplane, and that often times means using flaps. For example, the cessna 172s poh recommends 10 degrees of flaps for a short field takeoff. Why? By adding a small amount of flaps, you increase the lift your wing can produce, which is a good thing when you’re in a tight space.
Next up, as you taxi onto the runway, you want to have as much runway in front of you as reasonably possible. You know what they say: “there’s nothing more useless than runway behind you.” don’t make a big arcing turn onto the runway. Taxi straight ahead on to the runway, keeping an eye out for wing clearance, then turn to line up on the centerline.
Now that you’re lined up for takeoff, it’s time to make the short-field takeoff happen. Most aircraft recommend that you hold the brakes and smoothly increase your throttle to takeoff power. In most cases, you’ll want your mixture full rich as well, unless you’re at a high altitude airport (many manufacturers recommend leaning for peak rpm at high altitude airports). Once you’re happy with the sound of your engine, and your gauges are “in the green”, you’ll release your brakes and start rolling down the runway.
As your takeoff roll begins, you want to keep your elevator neutral to prevent any unneeded drag, until you’re ready to rotate.
As you approach your rotation speed, the real excitement sets in: liftoff.
When you’re a few knots under vr, you want to smoothly start pulling back on the yoke, so you rotate and begin lifting off at vr.
Once your wheels leave the ground, you’ll start accelerating faster, because you don’t have the drag of your wheels spinning against the ground. Since you want to climb at vx, your best angle of climb, you’ll most likely need to keep pulling back on the yoke and pitching up to prevent your aircraft from accelerating past vx (some manufacturers publish a 50-foot obstacle speed that’s slower than vx, so make sure to check out your performance charts before you fly).
Now for the last part of your takeoff: initial climb. You’ve already lifted off and pitched for vx, but you won’t just keep climbing at vx for the rest of the flight. You want to climb at vx until you’ve safely cleared your obstacles beyond the runway, then pitch for vy, which is your best rate of climb.
No obstacle in sight? Most manuals recommend climbing at vx for a minimum of 50 feet before accelerating to vy.
Once you’re clear of all obstacles and there’s nothing but blue skies ahead, pitch for vy, but do it slowly. If you pitch down too fast, you can develop a sink rate. And that’s something you don’t need when you’re still close the ground.
Your last step of the takeoff is to retract your flaps (and gear, if yours go up and and down) according to your poh.
COMMON PROBLEMS WITH SHORT FIELD TAKEOFFS
Short field takeoffs aren’t necessarily the hardest thing in the world to learn, but there are some common problems many pilots have: not using all of the runway (remember, runway behind you does you no good) lifting off too quickly: if you liftoff too soon, you’ll create excessive induced drag, and increase your takeoff distance not adding enough back pressure to maintain vx sinking when transitioning from vx to vy if you know the common problems, you’re that much closer to executing a flawless short field takeoff.
Now that you know how to make it all happen, it’s time to head to the airport and start practicing. After all, what better excuse is there to climb into your airplane and do some flying?