I've been waiting for this one to come out. The first one got me interested.

One thing I didn't see mentioned in that article, is the effect of long grass or brush on the take-off roll. That is something I deal with from time to time, and it necessitates a big change in timing and performance expectations. Other surfaces will slow you down too, but I find nothing drags you back to earth like a premature take-off in really thick long grass. In that case, or in bad gusty/turbulent conditions - my current practice is to stay on terra-firma as long as the runway allows, or until I'm at flying speed + gust spread, whichever comes first.

Battson,

Your are entirely correct about the detrimental effect of grass, especially tall and/or wet, on acceleration. That is why it is even more important to get into low ground effect, over the top of the grass, than on other surfaces. Yes the timing is different. As with any takeoff, we need to feel buoyant enough and have other sights and sounds that cause us to sense that we can get off and into low ground effect.

I think what you are witnessing with sluggish acceleration in ground effect is the attempt to climb once the mains are off. This attempt will get the wing out of effective (low) ground effect at slower than stall speed and the airplane will settle in a mush. We can fly at slower than stall speed in low ground effect. This fact can be useful in landing short, as well. On takeoff, however, we are after acceleration. At full throttle, we can also go the fastest in low ground effect. That is why it is less effective to stay on the ground. You are correct, however, that it is more effective to stay on the ground than to mush back into the grass attempting to climb when the airplane will not climb.

The hard part for many pilots is to immediately push the stick forward hard on liftoff. Cary made an excellent point about trimming for nose low or at least not trimming for climb. In his 182, trimmed for climb, a very hard forward push on the wheel to stay in low ground effect is required. We crop dusters and pipeliners never trim for climb because we never fly more than 200' AGL. We do trim for the load in the hopper but that just gets the nose to level. Also I teach a dynamic, proactive fore/aft stick control. Like with getting the tail up, it is easier for some pilots to put a lot of forward stick in and then take some out and then put a little more in, etc. all very quickly.

Try flying low over a cotton or alfalfa field. Keep working down until you hear a distinct tick, tick sound. That is the mains hitting a very minute part of the crop that sticks up higher than the majority of the plants. This is where we need to be over grass. Grass and trees don't give as much free energy in ground effect because the downwash is not completely arrested (action-reaction) until it hits the ground below the grass and trees are moved around by the downwash but don't give the solid bounce of a harder surface like ground or water.

Best Regards,

Jim

contactflying wrote:we need to feel buoyant enough and have other sights and sounds that cause us to sense that we can get off and into low ground effect.

Hey Jim,

I think the thing that surprises me most, is the effect of the long grass dragging on the tailwheel when you rotate.
When you feeling you're ready to fly, by usual standards, you rotate and the the mains (slowly!) drag-off into the top part of the grass. But tailwheel inevitably drops quickly back into the long grass with the rotation. This has a dramatic effect the first time you experience it!

I find if I don't add extra speed before lifting off, the extra drag from the tailwheel holds the mains in the grass for at least a second, and the added drag of the tailwheel + mains has increased total drag quite a lot. This can hold you down for a moment.

If I am loaded up heavy, bouncing back into the grass near the far end of a 600ft airstrip gets your pulse up a little. Happily, the Bearhawk is overpowered, so I can usually break free before it gets to that stage - usually. Once it's clear of the grass, there's enough power for immediate climbing out.

The tactical situation is always fluid. Getting off in 600' in high grass is doing good, however you do it. Hopefully you have an obstacles free departure path where you can get ground effect should she not want to climb yet.

I have tried this way to make landnings, but my Stinson 108-1 have way to far nose up in that landning-spot-configuration. Cant see the strip because of the high-nose in the window, if I targeting the correct slow speed! Seems to me that Stinson have a little bit to small flaps?

In antother way; if I fly the Stinson in a traditional landing-configuration (nose down) its very easy to "overrun" a decent landing speed. Once again; to small flaps?

Suggestion?

The tactical situation is always fluid.

These are great topics for discussion...Patrick has 'teed up the ball' with his video's...given us superb visuals to illustrate the aerodynamic processes...framing the topics...take-off...approach...landing. Pictures are truly worth thousands of words. Good stuff!

The shared experiences of each commentator here adds to the collective consciousness. Even if not immediately understood, read, file it away, explore. It seems to pay dividends in the future. Thank you all.

I bought a copy of Jim Dulin's book, Contact Flying, and it has been a liberating experience for my flying. Jim has a sublime, if at times unconventional, interpretation of the flying experience. Once you understand what he is saying, it makes a lot of sense. Not for the main stream GA pilot perhaps, but inspirational and appropriate here. Glad to see his commentary on this website.

Patrick, keep up the good work...it is all starting to come together. Can't wait for the next installment.

Stinsoner,

Smaller flaps are a problem. In older airplanes with no or little flaps and while using the power/pitch types of slow approach (hover taxi in low ground effect prior to touchdown point, dragging in, Patrick's level wing approach, or my apparent rate of closure approach,) we have to look out the sides of the windscreen. In your situation the trees on each side of the road should be visible to the bottom of the trees. Be sure to check for traffic on the road before turning final. I sprayed with an old Stearman that had a 4" tall metal rim around the hopper for the lid to close well. Even with cushions I couldn't see over that rim with the nose level. I asked the older crop dusters what to do about things that might be in the field I was spraying. "Look before you go," they said. To land short safely, we have to be slow enough we don't expect to need brakes. I have seen brakes cause more mishaps than they have prevented. That also means that we must touch down on the very beginning of suitable landing area. To touch down there at or below stall speed (ground effect,) we must use some kind of slow approach. To use gravity thrust rather than power/pitch without spoilers (like a glider) would be extremely dangerous on a one way (no go around possible except before you actually approach) like your situation.

Sideslip?

Stinsoner,

I have been in the situation you face numerous times with my own and leased airplanes. All were ugly work horses. I felt I had to make the following commitment to go to those fields: I am not going to kill myself going in there, but I may damage the airplane. Speed kills in all types of vehicles. Also shinny airplanes can cause a loving owner to do the wrong thing.

Yes, the forward slip (no crosswind) is helpful on the normal (high) approach. In your situation, I would be so low over the lake that a slip would put a wing into the water. That would eliminate any gravity thrust, which is harder to consistently control than is engine thrust.

Wll, I think You guys missunderstod me a little, the problem with zero frontsight duty to high nose is not just a problem when landning at my own backyard strip. The problem is always there when going to a slow-speed-setup. I was thinking about suggestions about different setup of the wings, maybe a STOL-kit or gapseals could change the angle of attack etc. Or a periscope?

slip it and/or look out the side - it's kind of what you do in a plane with no flaps - of course it's not as optimal - but you can train yourself to get used to it

Battson wrote:I've been waiting for this one to come out. The first one got me interested.

One thing I didn't see mentioned in that article, is the effect of long grass or brush on the take-off roll. That is something I deal with from time to time, and it necessitates a big change in timing and performance expectations. Other surfaces will slow you down too, but I find nothing drags you back to earth like a premature take-off in really thick long grass. In that case, or in bad gusty/turbulent conditions - my current practice is to stay on terra-firma as long as the runway allows, or until I'm at flying speed + gust spread, whichever comes first.

candidly I don't have too much experience with tall grass. Out in the west we deal with a lot of soft sand, which is a little different. I agree when conditions dictate there are reasons to hold in on for a while. I have also found that big tires take care of a lot of the soft/tall stuff. I attached a video from years ago landing at my buddies place which is at 5000 msl and had grass up to my waist in some spots, it was warm and being only 780' before a large fence I was real cognizant of the tall grass. It candidly that day had very little effect. I couldn't find the takeoff vid to upload, but you get the idea. I think this would have been untenable with 8.50s, but I am not real sure.

https://www.youtube.com/watch?v=Ga8JweAHjBM

Haha, who needs a lawnmower, just get a Maule!!!

stinsoner wrote:Wll, I think You guys missunderstod me a little, the problem with zero frontsight duty to high nose is not just a problem when landning at my own backyard strip. The problem is always there when going to a slow-speed-setup. I was thinking about suggestions about different setup of the wings, maybe a STOL-kit or gapseals could change the angle of attack etc. Or a periscope?

A little video camera under the nose connected to a screen on the panel. Just like the little back up camera new cars have.

Thank you for the great video, I enjoyed watching the entire series.

Even though I am a flatland pilot (Michigan), flying low wing Pipers, I still find them useful, as it can never hurt to be able to put the plane down exactly where I want, at the slowest possible speed.

I however have to admit, that it makes me really uncomfortable to fly at low altitudes this close to the stall speed. I am afraid that an unexpected gust might eat up the remaining reserve in airspeed, causing the plane to stall.

Am I overly concerned? How much of a gust factor should I add in gusting conditions? Still only 1/2 of the gust speed?

Oliver

Oliver,

Using the apparent brisk walk rate of closure approach, we don't get really slow until short final. By using elevator to maintain what appears to be a brisk walk rate of closure with the numbers, we continue to slow down as we approach the numbers. The lower and closer we get, the faster we appear to close. We control this apparent rate of closure with elevator and don't worry about airspeed, except to maintain buoyancy. Short, fat wing Pipers sink rapidly when slow. A great deal of power is needed to control this sink and stay on the desired glide angle.

Whatever slow approach used, we have to use both power and pitch and full flaps (if available) to have really good control. Gusts can be managed with aggressive dynamic, reactive throttle movement. The reason way too much extra airspeed is recommended for gust spread, is because little throttle management is taught with the stabilized approach technique. The airspeed stabilized approach technique is self defeating for short field work. It requires a round out and hold off over the numbers we are trying to land on. To make this work, we would have to try to hit the fence on approach (a good technique after engine failures where power is not available, by the way.) Neither Patrick's landing technique nor my apparent rate of closure technique require much round out or hold off, as we are already slow enough to land when arriving at the numbers.

Another short field technique with any airplane, but especially useful with low wing airplanes, is to hover taxi to the desired touchdown spot (numbers) in low ground effect. Normally called dragging it in, this technique requires no obstructions. An airplane can be safely flown much slower than stall speed in low ground effect.

Patrick,

I hadn't watched your video landing the Maule in tall grass before. I don't know if it was little tires or just a dumb instructor, but I turned a spray training Luscombe over in dry, ready to harvest, about that tall soybeans. I had landed in dry, ready to harvest beans before, but it was a dryer, less lush, year. It was a poor judgement thing.

Contact

@ Contact:

Thanks for the explanation.

Oliver,

If you don't already have it, email me at [email protected] and I will attach "Safe Maneuvering Flight Techniques." It covers this and other techniques.

Jim Dulin

contactflying wrote:Patrick,

I hadn't watched your video landing the Maule in tall grass before. I don't know if it was little tires or just a dumb instructor, but I turned a spray training Luscombe over in dry, ready to harvest, about that tall soybeans. I had landed in dry, ready to harvest beans before, but it was a dryer, less lush, year. It was a poor judgement thing.

Contact

Landing in soybeans is a great way to visualize the bottom of your aircraft....

Those things GRAB.

MTV