A true soft field (soft sand, muddy grass field in spring-time, etc.) robs a lot of power from your airplane and makes it take far longer to accelerate to takeoff speed than it would if it were to be on a hard-surfaced runway. Given that there may be much friction and drag the airplane may need an infinitely long runway to reach it’s normal rotation speed. We’ll show you the method to use in such a scenario to beat the odds and defy gravity yet again!
Ground Effect is the disruption of wingtip vortices that form when the high-pressure air from under the wing seeks the low-pressure air on top of the wing. That may sound fancy, but there is really only one simple concept I want you to take away from this….
Ground effect works the closer to the ground you are, and only works up to about half the height of your wingspan (i.e. an airplane with a 34′ wingspan will only enter the effects of ground effect when within 17′ of the ground or less).
Here’s what you need to know: Ground effect makes your wing generate more lift without additional drag. Sounds great, right?
It is great, it’s the only time you get more lift without extra drag, the problem is if you leave ground effect too soon before you have adequate airspeed, you might be generating enough lift to fly 5′ off the ground, but not enough to fly 50′ off the ground, and the airplane will settle back towards the ground if you are leaving ground effect without sufficient airspeed. This tends to result in you running into the trees at the end of the runway rather than clearing them. Be familiar with the appropriate speeds for your aircraft and what it will take to make your aircraft fly based on your takeoff weight and atmospheric conditions each time before you fly (be sure it is enough!).