When we move the stick forward dynamically and proactively to level the TW airplane or pull the yoke back to get the nose wheel just off, there should be an an accelerative surge.

When we use flaps and/or haul the airplane into low, level ground effect, there should be an accelerative surge.

Except on very short fields, we should now be able to see we are going to be able to accelerate in low ground effect long enough to achieve sufficient zoom reserve in the form of airspeed to safely rudder turn around or zoom just over obstacles.

I haven't played with popping the flaps yet. I'm going to try that and pay attention for the surge next time I do pattern work.

I think my airspeed indicator would need to be marked in 10ths of MPH for me to notice the "surge" in the 150. I'm usually just glad to make it off the ground and beat the kid racing me on his bike.

Pete

The smaller the engine, the more important the free ground effect energy. Ok, meybe not a really noticeable surge. Still, it is good to know we are off and level in low ground effect. Also, the smaller the engine, generally, the lighter the airframe. With light airplanes, it is amazing how they can be pitched, or flap lifted, into ground effect well below stall speed. It is critically important, however, to now level the airplane to stay in low ground effect.

At high density altitude, I have seen 150s roll on the surface almost the entire length of very long runways. It is safer and more efficient to pitch it up below stall speed and then level in low ground effect. Only after leveling do we receive the tremendous, especially at high density altitude, accelerative energy advantage of flying down a long runway rather than rolling down a long runway. The design of the airplane is to fly, not to roll on the ground.

Pilots often think the old 0-540 Lycoming powered Pawnee and Callair perform incredibly well because they are crop dusters. However the power to weight ratio, 235 hp to over 2900 lbs, is comparable to many four place people airplanes. The big energy advantage is that we work in low ground effect on every takeoff and in the crop field on every swath run. This kick in the pants makes us look good to those driving by while we are working. Yes there are jet crop dusters out there now and the boss will fire the pilot who works his million + airplane really low, but they are working long wings at incredible airspeeds. Without the aggressive wingover, they can't get slow enough to make the turn when working back and forth to return to the field sixty feet from where they left.

pburns wrote:I think my airspeed indicator would need to be marked in 10ths of MPH for me to notice the "surge" in the 150. I'm usually just glad to make it off the ground and beat the kid racing me on his bike.

Pete

Aye, and its kinda hard to pop electric flaps , so no second surge there.

Even the FAA has come on board with the latest PTS. The applicant is now required to "accelerate in ground effect to Vy or Vx as appropriate. "

It would have been helpful had they required, "accelerate in low, level ground effect to Vy or Vx as appropriate. "

I was taught that "accelerate in ground effect to Vy or Vx as appropriate. " means leveling off in ground effect as low as practical (without the tires touching). That can't be much different from "low, level ground effect".

Remember we're talking about a federal agency,sort clipped sentences typical of bureaucracies.

Yes, and they probably don't want to go into water skiing. Getting a C-150 into ground effect in high density altitude, with or without ten degree flaps, is like getting your butt just out of the water behind an 18 hp Evinrude, like I learned. Until you level the skis to get on the step, thing are really wobbly. When behind the power curve: If you pull the C-150 off and it won't continue going up (it won't, it will just wobble in a high pitch attitude pulling too much air), try pushing forward a bit to get level in low ground effect. It is like that squat move that weight lifters do to get under the load, once up.

Actually,

All joking aside, when I fly the 150 i almost always fly in low ground effect on take off and do notice an increase in airspeed when I get the nosewheel off and again when it gets off the ground. Our strip is grass and can be a little soft at the start and many days I don't even start to register airspeed until the nosewheel gets off. I don't think I could get to Vy by the end of the field. I'm usually around 60 - 62 when I climb out of ground effect and then nose over a bit once i have cleared the trees at the end of the runway which gives me enough air speed to feel good about raising the flaps (I like 10 degrees on take off, I have tried several different settings) which makes a huge difference in getting better acceleration to Vy or whatever airspeed I'm looking for. Always looking for good advice/helpful tips.

Pete

Well said, Pete. If it won't fly in low ground effect relatively soon, it won't fly after rolling a long way on the ground relatively late.