• If You Are Having Trouble Logging In with Your Old Username and Password, Please use this Forgot Your Password link to get re-established.
  • Hey! Be sure to login or register!

STOL Techniques-from an Article by Mike Vivion

PA12driver

Registered User
Battle Ground, WA
S.T.O.L Operations

The acronym S.T.O.L., which stands for Short Take Off and Landing, conjures up images of all sorts of aircraft modifications in most pilots? minds. Leading edge cuffs, stall fences, vortex generators, drooping ailerons and so on are all aircraft modifications intended, or at least claimed, to have near magical effect on the short field capabilities of an airplane. Having flown aircraft equipped with many of these modifications, I can attest to the fact that most of them do have some noticeable effect on the performance of the aircraft, and some have quite a lot of influence on the manner in which the subject aircraft performs in the slow speed end of its flight envelope.

The most effective STOL ?kit? available though, is not installed by a mechanic. The single most important factor contributing to the safe operation of an aircraft in the short field environment is the skill and knowledge of the pilot, not the number of gadgets attached to the airplane.

So, what are the magic skills possessed by the heroes of the horizon, those bush pilots of renown? And how do we mere mortals learn their techniques, so that we too can safely operate our aircraft from a postage stamp size strip? For the most part, these techniques are simple: absolute adherence to basic piloting skills which we all should have learned in our earliest flight training and a fanaticism for precision.

The task before us in the short field landing is really pretty simple: Touch down at a specific point, with the airplane at minimum safe forward speed, and at the minimum possible weight, followed by application of maximum braking. Steering comes in there somewhere, too, but these are the real priorities for short (as opposed to narrow) field operations. This is an exercise in physics, folks: mass times velocity equals inertia. Minimizing the inertia at touchdown, then dissipating it in the minimum amount of space is the name of the game for short field operations.

To start with, I always try to fly a rectangular (or modified rectangular) traffic pattern to a short field landing. There are a lot of good reasons to fly a rectangular pattern, it helps to gauge our progress in the descent, and gives us perspective of the landing area. Remember, though, the pattern altitude in an off-airport setting doesn?t have to be 800 feet above the surface, and the pilot should keep the patterns close in to the intended landing site.

Airspeed control throughout the approach is critical. An old saying has it that it is next to impossible to turn a bad approach into a good landing. Airspeed on short final is even more critical in the short field venue. Too much speed and the airplane will float well past the intended landing point; too little speed, and we may land a bit short of the ?airport?, and have to walk home. So, what airspeed to use on short final? Obviously, the specific airspeed for each model of airplane will be somewhat different, so all we can do here is develop some basic guidelines. The FAA advocates 1.3 Vso (one and one third times the power off stall speed with flaps deployed) in its practical test standards for approaches. While 1.3 Vso offers a comfortable margin in a normal landing approach, and it works fine on downwind to a short field, it won?t work on final in this environment. I use an approach characterized by different speeds on different portions of the approach. Downwind and base leg may be flown at a relatively fast 1.3 Vso, while short final will be flown at somewhere very close to Vso and the speed at touchdown will be even slower. This offers a lot of margin on the initial portion of the approach, yet minimum forward speed at touchdown. Remember that most airspeed systems on our aircraft aren?t very accurate at very high angles of attack, so this should all be practiced at a safe altitude, with a competent instructor, until you have a really good feel for the airplane in this configuration, and know what all the indications are at minimum controllable airspeed. If your airplane has been modified, the pilot operating handbook may not offer very accurate information on the actual stall speed of your airplane. On the other hand, DO NOT take the performance claims of the manufacturers of the various STOL devices as gospel. Every airplane, and every pitot static system is a bit different. Find out for yourself, at a safe altitude what minimum controllable airspeed is, and what the stall characteristics are for your airplane. Again, the assistance of a competent instructor, experienced in your aircraft type, is invaluable in this process.

Short field approaches will nearly always entail a fairly flat approach, and the use of some power. Power helps manage our descent rate, and the use of some power reduces the stall speed of the airplane significantly. For example, the power off stall speed of the Aviat Model A-1 Husky is given as 43 mph by the pilot operating handbook, while the power on stall speed is 37 mph. The propeller slipstream keeps the airflow attached to the inboard portion of the wings and tail surfaces, permitting the airplane to fly at slower speeds. By using power, we can take advantage of a slower approach speed, while still maintaining a safe margin above the stall. Remember the physics: mass times velocity?. Our task here is to arrive at the touchdown point at minimum safe forward speed.

As the airplane touches down (precisely on the intended touchdown point, of course) the throttle comes back to idle, and the airplane should be all done flying. The idea here is to slow the airplane to below power off stall speed precisely at the moment of touchdown. This is what pilots are referring to when they speak of ?hanging it on the prop?, and while at first blush, this seems like a bit of a daredevil operation, it really isn?t when properly carried off. In many aircraft, you will be operating in the ?area of reverse command? (or ?behind the power curve?), where the only way to climb is to lower the airplane?s nose, something to keep in mind if a go-around becomes necessary.

In a tailwheel airplane, I favor touching down very tail low, with the tailwheel a couple of inches off the ground, and at the first touch, roll the airplane up onto its main wheels. This places the maximum weight on the main wheels, permitting maximum braking effectiveness. In a tricycle gear airplane, this all tends to take care of itself, by holding the nose wheel off as long as possible. As soon as possible, retract the flaps, again to maximize braking effectiveness. In my favorite venue-floatplanes, raising the nose while retracting the flaps offers awesome deceleration, and very short landings. However, the approach techniques are the same regardless of whether your airplane is equipped with wheels, floats or skis. Once again, these are techniques which should be practiced extensively at a safe altitude with a competent instructor.

We must practice, practice, and practice our approaches some more so that every touchdown is precisely on the spot we have chosen, with the airplane at target touchdown airspeed. This practice needn?t be done on a gravel bar somewhere in the bush. A can of surveyor?s spray paint (the kind that works upside down) can be used to mark off a touchdown box on a little used private airfield. Make the box about ten feet wide and ten feet long (or however small you feel up for), and locate it a safe distance from the actual approach end of the runway in use. Again with a competent instructor, start working on that precision until you can touch down in the box every time, at minimum forward speed. Once you can consistently do so, you are well on your way to successful short field operations. Now, practice some more. Look for nothing less than perfection here.

Any short field approach which is not working out precisely as planned should be abandoned, and a go-around initiated as early as possible. The pilot should always be prepared to initiate a go-around-unless, of course, you are operating into one way strips. Landings on short one way strips are sort of like sky diving?they really need to be pretty much perfect the first time.

Most of us don?t get to perform a large number of landings, and since short field landings demand the utmost skill and practice, I contend that we should make nearly every landing and takeoff a maximum short field operation, unless conditions (such as very gusty crosswinds) dictate otherwise. Even if you are landing on a ten thousand foot runway, choose a touchdown point on the runway, set up a short field approach to that point, and do your best to land on the point, and stop as short as possible. Performing this maneuver at the very approach end of the runway, with three thousand feet of runway ahead of you to the next taxiway may not endear you to ATC, so you might want to choose a landing zone near a taxiway.

Well, now that we have managed to insert our airplane into this small version of an airport, how are we going to safely get it out of here? First, we need to be familiar with the climb characteristics of our airplane. Many aircraft have been so extensively modified that the numbers offered in the pilot operating handbook aren?t even a very good starting point. There are formulas which will derive theoretical best angle and best rate climb speeds, but you need to practice anyway, so why not turn your practice sessions into an effort to determine the best climb speeds for your airplane? Start with the factory recommended airspeeds, then experiment with other speeds and configurations, using timing and altitude to derive best rate and time over a known distance to determine best angle. Remember that weight of the airplane has a dramatic effect on best climb speeds?the lighter the plane, the slower the climb speed for maximum performance. And, not only do we need to determine the best angle of climb speed, but also the configuration in which that speed will achieve the best angle of climb. Figures given in the pilot operating handbook for most aircraft are numbers for the airplane at gross weight, unless otherwise specified.

Some of these numbers and configurations can seem sort of scary. For example, the Super Cub handbook recommends a best angle of climb speed of 45 mph, with full flaps. If the engine fails in that configuration, you will note some interesting pitch changes, to put it mildly. Nonetheless, this is the speed at which the manufacturer recommends you depart for maximum obstacle clearance, assuming an aircraft weight of 1750 pounds. Been operating your Cub a bit over 1750 (with a Wipaire STC, of course)? Don?t ask me what the best angle of climb is, you will have to determine that yourself. This should be done at a safe altitude and with the assistance of an instructor to assist from both a safety standpoint, and to help keep track of data. Just remember that if you are deviating either up or down from the weight used by the manufacturer to determine best climb speed, the speed will also change.

Holding the airplane?s brakes prior to takeoff while applying takeoff power may be a reasonable short field technique on paved surfaces, but if you value your propeller, holding the brakes while running up a lot of power on a gravel strip is a bad idea. Besides, most paved runways aren?t really very short, either. A rolling acceleration, with power gradually but steadily applied, will serve well on most short strips, while keeping your propeller serviceable.

I prefer a tail low takeoff technique, with the tailwheel just off the ground, but again, it is important to understand what the manufacturer recommends for your aircraft. Allow the airplane to simply fly off when it is ready. I also prefer to set the flaps prior to starting the takeoff roll. Some pilots prefer to add flaps after they are rolling to assist the initial acceleration (the theory being that the flaps initially create drag), but for me at least, fiddling with flaps is a distraction I can do without during this critical phase of flight. The primary exception I make to this policy is in certain aircraft on floats, where adding a quick bit of additional flap just prior to takeoff works quite well. For years, the Gulkana Air Show included a short takeoff and landing contest. You could see about as many techniques for short takeoffs there as there were pilots in the contest, but two things seemed to prevail: The lighter the airplane, the better the performance, and the folks who let the airplane fly off without a lot of massive pitch changes seemed to perform consistently well in the contest. Again, we need to ensure consistency, as well as performance, so I don?t advocate a technique that requires a great deal of finesse, and is easy to botch. At least not until you are confident that you can perform the technique flawlessly every time.

From your private pilot lessons, you may recall that after a short field takeoff, you should accelerate to Vx, or best angle of climb speed, until all obstacles are cleared, then accelerate to Vy, or best rate of climb. This all works well in my book, and I would add little to this, except to note that if you do not have to clear any obstacles, you may just as well accelerate directly to Vy. Remember, unlike in our private pilot training days, the task isn?t to clear an imaginary 50 foot obstacle, it is to clear a very real obstacle of undetermined height. I often tell my students that all you have to do is clear the obstacle, you don?t have to clear it by 200 feet. The message? Don?t operate the airplane at very slow speeds in the climb (Vx) unless you really need to. I would rather climb over the obstacle at a slightly lower height, with a bit of extra airspeed.

The second ?free? STOL kit we can install in our airplane is actually something we take out of the airplane. If you talk to any number of pilots who regularly operate in and out of short fields, they will consistently tell you that to operate into truly small spaces, you simply will not be able to operate the airplane at gross weight. This applies to landings as well as takeoffs, by the way. I have heard a lot of pilots who refer to ?going in heavy and coming out light?. While this may work on a given landing site, it doesn?t necessarily mean that the airplane will be at gross weight during either the landing or the takeoff. Again, remember the physics: Mass times velocity equals inertia. Once the airplane is on the ground, braking is all we have left to stop it. The lighter the airplane is when it touches down, the less braking required to stop it.

Here?s a news flash for you Super Cub drivers: The stall speed listed by Piper for the PA-18, at 1750 pounds gross weight, is 42 or 43 mph, depending on which model you have. Wipaire has certified an STC to increase the gross weight of the Super Cub to 2000 pounds. The new stall speed listed in the Wipaire supplement for the Cub at 2000 pounds is 53 mph. The original Aviat Husky A-1 had a stall speed of 43 mph at 1800 pounds, but the newest Husky-the A-1B, has a stall speed of 54 mph at 2000 pounds. Aerodynamically, the lighter gross weight version of these airplanes does not differ from the heavier version-they are aerodynamically identical. Only structures and weights are different, but what a difference a few hundred pounds makes! This should be a lesson for us all.

Keep this in mind when you are preparing to fly out to that sheep strip. Can?t survive out there without all your ?stuff?? Make two trips. Or three. I recall several years ago watching an air taxi operator with a Super Cub ferrying hunters to ridge tops in the Alaska Range from a larger strip where the hunters were dropped by a Cessna. Every trip, the pilot filled a 2.5 gallon can with gas, and added it to the airplane. That pilot knew the capability of his airplane, and understood that the lighter the airplane is, the shorter the required runway. Just don?t make the mistake that many pilots have in Alaska, which is to load the airplane to (or well over) gross weight, and then expect it to perform. It won?t, and hanging another device on the leading edge isn?t the best solution to this problem.

Now that I have beleaguered you with the notion that the pilot is the real key to effective short field operations, here are a few ?STOL modifications? you can apply to your airplane which will absolutely, positively, produce shorter takeoffs and landings, assuming proper pilot technique:

Install a lightweight starter?weight savings: 10 pounds or more

Install a dry cell battery, and shorten the cable runs by moving the battery as far forward as possible?weight savings: 10 to 15 pounds.

Remove all that wiring, plumbing, and equipment that hasn?t done anything in your airplane for years. You would be surprised at how much old wiring adds up, weight wise.

And, finally, the toughest one of all: lose a few pounds off the pilot. Hey, it?ll not only improve the performance of your airplane, but it will keep you flying longer by improving your chances of passing that flight physical.


So, the keys to short field operations are:

1. Practice until you can precisely place your aircraft where you want it every single time, at minimum safe airspeed.
2. Keep the airplane light, both for landings and takeoffs. Make two or three trips if necessary.
3. Always be prepared for a go-around if necessary.
4. Determine and commit to memory the best speeds for your airplane, and practice climbs and descents at these speeds regularly to maintain proficiency and familiarity.

That?s all there is to it, folks. Sounds simple doesn?t it? And it is?just takes a little focus and determination. As well as a good bit of skill and lots of practice.

Safe flying to you!

Posted by Mike Vivion, May 16, 2002, 11:31 pm



View a list of articles by Mike Vivion
 
Hey Mike, while I agree with virtually everything you said, and think it was eloquently said...... Isn't mass times velocity equal to momentum rather than inertia? And back in the days when I had need for such things, I usually brought the plane in with power at less than power-off stall speed, chopping power as I touched down while trying to touch down near power-on stall speed rather than power-off stall speed. You get down slower and get stopped faster that way, but it isn't quite as safe, and that might be why you chose not to do it (consistant with the relative safety you promoted in the rest of your post).

All the best,
JimC
 
Jim C.

I agree Mike's article was very good, "conservative" and safe. You are right in that most practical applicaton of "technique" lends one in real life to use a combination that usually ends up somewhere (above power off) stall speed and that of power on. The goal still being to land at the slowest speed possible to stay in the air till precisely the "chosen spot" any yet have enough cushion to account for the "environmental" variables that can not be "engineered" into the application)

I am always impressed by your quick pickup on the engineering aspect of these discussion. (I would love to sit and learn from you) as all my experience is seat of the pants!

We will fly together one day!

Tim
 
Power on, nose high, critically slow, catch a swirling draft coming over the trees, and pow....instant pancake. Can't arrest the descent rate fast enough to go around, or can't climb fast enough to miss the trees at the end of the runway. I still like the nose-low, hand-on-the-throttle approach.
It's a favorite subject, though. Take some guys to a gravel runway for a contest, and everybody does it your way. Take them to a patch of dirt in the trees???
SB
 
Hi Tim, thanks for the undeserved compliment. Didn't I say 'below power-off stall' (slower than), rather than 'above' (faster than). When conditions safely permitted and the need was there, I used to come in substantially slower than power-off stall speed carrying a lot of power, which was what I considered to be 'hanging on the prop'. I no longer fly well enough to get away with that. One of the penalties of growing old and incompetent.
Jim
 
Jim,

Don't under-rate yourself, if you are limber enough to get into the front seat, feet will still work the rudder and heels work the brakes, and you practice couple times a week, you can fly better then 99% of the 25 yr olds that just think they can! Bob Hoover is such a good example of that! I flew for years with a cub pilot that was 80+ that could fly rings around my 50 year old butt!

Keep with it, and believe you can! "I do"

Tim
 
Well Tim, I dunno. I quit playing tennis when I was no longer able to play at a professional level. I can still get in the front seat of a cub OK, but do have to struggle a bit more to fasten the seat belt. When I start feeling that I'm a danger to a perfectly good airplane, I'll stop doing that too. I'm not there yet.
JimC
 
"Short field approaches will nearly always entail a fairly flat approach..." is pretty scary if there are trees in front of the runway.

Does anybody like the "stall-down" landing technique as described in "Stick and Rudder"? It requires a lot of practice, but has many virtues:

1) Relatively high (~70 IAS) power-off approach speed allows plenty of margin for sudden wind shifts and gusts near the ground. (I've had a 15 MPH headwind quit at 50 feet, just under the treetops -- you are really glad for the extra buoyancy instantly available by kicking the slip straight and punching the throttle!)

2) Steep approach angle makes the most of a short runway beyond tall trees.

3) The deaccelerate to landing (stall-down) technique, correctly executed, results in the plane touching down, with no float, at the point where your approach path intersects the ground -- your approach never "flattens" out, and you don't waste any runway.

For those who may not be familiar with a "stall-down" landing it goes like this: With power off, maintain adequate airspeed (I use 70 IAS) on approach, and establish a steep angle with flaps and/or a forward slip. (Unlike some other planes, Cubs are very predictable in even radical slips.) On very short final, slow the plane down by raising the nose -- keep the approach angle constant by controlling the rate of raising the nose and by modulating the slip, if necessary. The goal is to deaccelerate the airplane while maintaining a constant aproach path, such that the speed left at the ground is just adequate to flare, with no float. Full throttle is available, if you misjudge (as long as you recognize it in time).

When I flew to Alaska in the '70s, I got into a short-field landing contest with some locals who used the "drag-it-in-and-let-it-drop" technique, which gave me the heebe-jeebes, especially over dense forest. I had been practicing my "stall-downs" for many hours before the trip, and I beat the pants off of them at every strip with obstacles on the approach.

This is a really fun and useful skill to learn (especially since Cubs are so friendly in slips), and I think more Cub Drivers should give it a try. It's the best short-field technique that you can use in a power failure, for example (where you might really need to get into a short field!). For some reason, it seems to be little known -- the only pilot I knew who used it a lot (other than Wolfgang Langewiesche, apparently, who wrote "Stick and Rudder") was the United pilot who taught it to me, and who could do some really amazing things in his PA-11.
 
Hey Older...........I can see the steep approach theory but why at such a high speed? You indicated that you've had a 15mph headwind quit at 50 feet yet you say to slow the aircraft on short final so that you have no float upon flaring. Unless I missed something, you are landing at minimum speed above stall with no power. With a steep approach and carrying some power you can actually fly slower on the approach and the cub quits flying instantly when the power is chopped on the flare.
 
Stall-Down Landings

Cubdrvr,

The approach speed you use is largely arbitrary. I like to use 70 IAS, since I learned to fly in the Colorado mountains where high density altitude and gusty, changing winds are common. 70 gives me enough margin of error to feel comfortable approaching a small, unknown strip surrounded by wind-disturbing terrain obstacles. (Getting behind the power curve, as the article which started this discussion seemed to advocate, is a really dicy thing to do at altitude fields, BTY)

Any approach speed (that allows you to maintain your desired approach angle) is OK, since you get rid of it all in the last 100 feet or so. You deaccelerate the airplane while maintaining your approach angle by mucking around with the nose attitude, flaps, slip (and power, if you are carrying any). This makes the last 100 feet of the approach pretty busy (which is why it takes practice). The ideal is to arrive at the ground with just enough speed to kill your descent rate, at which point the airplane is stalled and settles on without any down-runway floating. (On the other hand, if you goof and the airplane stalls WHILE you are trying to kill your descent rate, it looks a little like a "carrier" landing :( .) The time (and height) you spend near the stall speed (where you have very little margin for error or abruptly changing conditions) is minimized with this technique -- the more so the more rapidly you can deaccelerate.

There is no reason why you can't carry power on the approach. As you point out, it gives you one more tool to use in slowing down at the end. I like doing power-off approaches, however, since they are practice for forced landings and I've had the engine quit enough times to feel quite paranoid about it by now.

If you are interested, I highly recommend that you look at the description in "Stick and Rudder" -- Wolfgang does a much better job of exposition than I. He has a lot of specific suggestions about how to manipulate and judge your remaining speed (he uses the term "bouyancy") during the approach. I think that the reason so many people stress using slow approach speeds is that they are not familiar with the techniques which allow you to quickly bleed away speed (especially in a slip-friendly airplane like a cub).

(The basic deacceleration technique is just pulling the nose up. If you pull it up rapidly, the airplane will balloon above the glide path -- if you pull it up slowly, the airplane will slow down and sink below the glide path: Hence there is a rate to pull the nose up where the airplane will follow the same glide path while slowing down. If you start this at the right point, you will arrive at the ground almost stalled. If you use flaps and/or slips as well, you can start the deacceleration proceedure closer to the ground.)

One of the fun things about this landing technique, is that the other pilots watching you will wonder how the heck you are doing it!

Older...
 
Gonna have to try that method.........you got me curious now. I like the theory of what you've said but does it work in all environments or just when you have stable air? I've read Stick & Rudder twice and highly recommend it to anyone flying anything. It's ironic how Wolfgang's book written so long ago points out the number one cause of fatal aircraft accidents.............and that cause ( stall/spin at low altitude) maintains the lead position to this day. Changes are needed in our primary flight school curriculum where students learn to fly the aircraft. Maneuvers involving slow flight, steep banks, and cross controls might help.........and also that "seat of your pants" sensation that's trying to tell the brain something.
 
Cubdrvr,

Like all flying techniques, it works best in good conditions :-? -- however, you can use stall-down technques in squirrly conditions to maintain a larger margin of safety -- higher approach speed, more power in reserve, etc. You might also want to leave a little extra speed (and accept some float) at the touchdown.

I haven't flown for about 12 years (due to personal reasons) but am hoping to get back into it soon -- I was glad to find that the Super Cub didn't die when Piper abandoned it (Imagine dropping your most wanted airplane! What were they thinking?)

I've actually flown a couple of times in the last decade, when I found a place where I could rent a Cub. Both times, the instructors that went along were very uncomfortable with any maneuvers that even began to approach what Cubs are capable of. Once, I ended up giving an hour-long "lesson" to the instructor about slips in Cubs (-- and for that I paid $85!).

Of course, two experiences don't a trend make, but I'm glad that I didn't have to learn flying from them. My own instructors really put me through the wringer -- when they pulled a "power failure" they sometimes made you really put it down in a field. (Of course, it was probably a field they had checked out earlier, but I didn't know that.)

For whatever reason, it seems that students aren't given the same depth of instruction -- in, for example: stalls, spins, slips, off-field landings, hand-propping engines, etc. -- that used to be standard. I suspect lawyers have someting to do with this, but its the students that suffer.
 
Just wanted to add a little something here for the newbies, from the perspective of a fellow newbie. I sure don?t claim to be any sort of an instructor (I?m a newbie), so take this with a grain of salt, and decide for yourself wether you want to try this.

From my limited experience (16 years and a couple hundred hours), I can now say that I?ve had one good instructor (my original) and a bunch of others that just sat over there and criticized my every move. But none of them (to date) have done much to teach me about STOL technics. I believe the reason for this is;
(1) There?s an instinctive fear that comes along with getting really slow when you?re low enough to know that you?re going slow, but high enough to know that if you fall out of the sky, you?re going to get hurt.
(2) They didn?t have the right plane, which leads to
(3) They themselves don?t have the experience, so how can you expect them to teach you what they don?t know.

My newest instructor (the SuperCub guru) cut me loose after 5 hrs with the statement ?OK kid, you?re ready to go. Now all [she] needs is some time to get to know [you], so go out and put another 50 hrs on her, and then call me back so that I can show you how to fly it?

I thought that was pretty wise of him to say that. He understands that you need ?seat time? to get to know your plane. I think I?m going to end up really liking this guy.

But alas, I once again drift further from the point that I wanted to make.

I?ve learned more from stick & rudder, and this site, then any instructor has shown me. But as my first instructor used to say, ?reading it is a good thing but, riding it is what counts?

In an effort to teach myself some of these STOL technics, I?ve been dragging the entire length of my one mile runway while practicing touch and goes. If a tire doesn?t unintentionally touch every once in a while, you?re not doing it right!

Practicing slow flight at a couple thousand feet is good, but doing it one foot above the runway is teaching me just exactly how this plane flies, and in a safe environment.

By doing this, I?m learning how variable winds effect my ?float?, and how to ride the plane when it?s behind the curve and mushy. I?ve greatly improved my spot landing score, my short field abilities, and it?s demonstrated to me the fact that I still can?t predict just how far a tailwind will push me. Also, try to find some willing sucker (that?s a glutton for punishment), and put them in the back seat so that you can practice this at different weights.

Well I?ve gone on long enough. For my fellow newbies that are just starting to learn how to do this stuff (STOL), I would suggest that you try ?dragging the field?, there?s a lot to be learned there, and it?s a reasonably safe place to start.
 
Cavy,

Now that your're doing this, you can add some new tricks. Add a couple notches of flaps, raise the tail on T.O. and when it starts to fly throttle back to about 11-1200 and just roll down in ground effect as you've described, keep it straight with right rudder, roll in some left stick and feel it roll up on the left tire, go back to neutral, hold straight with the left rudder, roll in some right stick, back to neutral, and repeat for however many times you can with the runway available. Called "wheelwalking." You want the wind calm or directly on the nose.

Excellent what you're doing on the runway, you're going to make a good SC pilot, I can tell.

Another thing you can do with speed is keep the wings level with the stick and use the rudder to go from side to side on the runway, litterally driving it around with your feet while keeping the wings level. It is the way ag-pilots can drive their planes around obstructions on a field as you cannot dip your wings in the crop. Good for anytime you have speed and need to drive around some obsticle without gaining altitude. Doing it on the runway environment will give you the confidence.

Great stuff you've posted. Good luck!

Matt Mattson
http://www.treasuresites.com
 
The most dangerous moment in flying is the transition from a ground vehicle to an air vehicle, and vice-versa. To extend your time in that environment is dramatically increasing your chance to learn that infamous maneuver....the groundloop.
SB
 
SB:

Agreed! That's why you learn the wheel walk with flaps, if it starts to dart, or you get nervous, simply give it a little back stick and you're flying in ground effect. When you get more confident, go to 1 notch, then none, etc. I'm not suggesting everyone try this without plenty of practice doing what he's (lawndart) doing already.

In driving the runway from side to side, you're already flying, and the long runway gives a ready reference for how good a "driver" you are.

MM
http://www.treasuresites.com
 
Matt's right. I used to land a lot on the top of the Mississippi and White River levees. It was sort of fun because the top of the levee was only a couple of feet wider than the wheel track, because the gusty crosswinds over the top of the levee created an erratic moment on the roll axis, and because ground effect was greatly reduced by the downward slopes on either side. I can't say that I ever thought it was particularly safe, but it was great practice and really helped with learning to keep the J-3 on the particular alignment that you desire.
JimC
 
Well, you Florida boys must have a different agenda for what to do in an airplane than me. The idea is to get into or get out of a landing area. Flying is flying. Landing is landing. Pick your technique. Soft field, short field, REALLY short field. Practice that. Wait for a turbulent day with a 20 knot quartering wind. Go do touch and goes. Pick the technique and commit to it. Hit your spots. Control your rollout. That's practice that IS worthwhile. Mastery of an airplane that's in ground effect is a skill you don't need. The point is to get on the ground, or get off it.
SB
 
Ground effect.

Hi SB. Hey buddy, you might want to lighten up a bit on ground effect. After all it is something we have to visit on each takeoff and landing. How long you stay in it is variable. I agree 100% that it is a dangerous time of the flight. Winds make it very dangerous. Winds not on your nose that is. But so are stalls and we practice them all the time. They are close cousins. Ground effect is where I am after I shake free of the muck and am waiting for best angle speed. It's also where I spend 135 miles of each trip to Alaska. I can pick up a full 6mph for the entire length of Lake Williston. At my speed it's well worth the while. I stay close to shore to be sure. I agree with all of your other forms of practice, especially on the rainy windy days, when everyone else is watching the tube. You never know what you might encounter around the next corner when traveling X-country. You want to be the very best you can possibly be in ALL modes of flight. :D Jerry.
 
Jerry,
You got me. BUT.....you are at cruising speed, straight and level, with a little more than "a couple hundred hours." To practice dragging it for a mile, dirty, let alone stomping on the rudders....not me. I, by the way, also accelerate in ground effect on almost every take-off. But it's at full throttle with the intention of getting out of Dodge.
SB
 
Stewartb

Well.....I?ve re-read the last few posts and I?ve deleted a half dozen of my replies just before hitting the submit button. All I really want to say at this time is: Technic.

Technic?...where the hell did that come from?...damn spell checker will always help you spell the wrong word the right way. Me-> :splat:
 
Cavy,
What did that mean?

Anyway, you should practice as you see fit. Just be prepared to respond.
SB
 
I'm with Jerry re ground effect. When working the Mississippi and White Rivers, I spent a lot of time cruising in ground effect because it allowed me to search a substantially larger area per unit time and per refuel. Years later, I'm still interested in the physics of flight in ground effect because the big pterodactyls that I work on now were fresh water skimmers that spent a large fraction of their time flying in ground effect. Nothing wrong with doing so. But again, I wouldn't say it is as safe as being a few thousand feet off the ground. Sort of depends upon what your needs of the moment might be.
JimC
 
STOL OPERATIONS

Mike Vivion's narrative on STOL Operations is excellent. Good advice for a young or low time pilot who wants to learn bush flying operations. However, If I have learned anything about bush flying; it is, that it is not simple and that it takes a tremendous amount of time, concentration, thinking, etc. to gradually, step by step, improve skills toward the true Alaskan bush pilot level. Another is that there are many ways of doing bush flying operations versus the thinking that there is one best way. There are too many variables with airplanes (one SC up here usually has different modifications from another and fly's different), too many constantly changing variables in weather, too many different variables with bush landing areas, and too many variables in pilot skills and capabilities to believe that there is one simple technique for learning bush flying operations. Its personal; each pilot has to learn for himself / herself what is the best technique for you as a pilot and for the aircraft.

Mike Vivion likes to use the standard rectangular pattern for a short field landing approach with airspeeds tightly controlled for all legs and short final. This is the 'fly by the numbers' that all of us were taught as student pilots. This is the standard flight pattern. This is 'in the box' flying. Some bush pilots in Alaska, I don't know how many or what percent, but I believe fly 'outside the box' most of the time. We don't fly anything standard or by the numbers! We are more 'self taught' bush pilots that learned to fly bush operations out on a gravel bar alone. This type of flying is more an art than a science. We Practice! Practice! Practice! Trial and error until you find a way to confidently master every bush operation! Experimental, probably so! I'd better digress here on the experimental operations and provide a little bit of caution. Take small steps into the unknown or higher skill levels and there will be no serious consequences if you make small errors or miscalulations.

Tha advantage of this type of bush flying is that your airplane has been in almost every type of situation or configuration that is possible and you have learned to quickly recognize it, not get rattled, but how to efficiently and with confidence change flying conditions to whatever you want. You don't have to remember any numbers but just react to what you have seen many times before. This means you will not find your aircraft in a situation that you have not experienced previously and you already have practical experience of how to change controls to alter current conditions.

The approach to a bush landing can be made at any altitude, the traffic pattern any size. The pilot must focus on what is important- the immobile touchdown point. A second task is to make certain that the aircraft speed at touchdown is correct. Being an unorthodox pilot, the aircraft can be quickly altered to accommodate these two constants at any time, whether the aircraft is far out or close in, high or low elevation in relation to touchdown. This is of great value in gusty winds when the standard pattern and normal airspeeds means virtually nothing. Using these techniques, rarely, if ever, will you need to make a go-around.

There is so much more but I wonder if this is making any sense?


Cub Special Driver
 
Jim C:

If you're interested in large aircraft operations in ground effect, you might want to dig for some of the work Martin did in the late 50's early 60's and the work the Russians did on similar 4 engine jet short wing bombers designed for flight exclusively across the Atlantic using ground effect. You can catch pics of them on Disc. channel Wings on seaplanes.

Our operations in Ag were largely in ground effect, which is why they were practiced extensively. The most danger is pulling up out of ground effect on the first runs, since that cushion of air wasn't there to support the weight. As long as you were in the safety of ground effect, it was very hard to ball one up. Fertilizing was also extremely hazardous since it was done out of ground effect, and there was no way to dump the load. It is hard for many pilots to view the ground as their friend, but certain types of operations require extensive ground effect flight, and one learns that cushion of air beneath the wings results in significant fuel savings, and with some practice (driving) increased safety over the pilot that flys slightly out of it.
 
Sorry SB, it was a bad attempt at humor, making fun of myself for using the word technic instead of technique. But I muffed that post too.

My first instructor was a real cowboy. By that, I don?t mean that he wore a big hat and elf boots (sorry Murph) but I mean that he knew how to ride an airplane. He?s the one that nicknamed me lawndart after I accidentally spun a C-150 while under the hood, but that?s another story.

Where I?m going with this, is to say that I haven?t had an instructor since, that had the nads (or the knowhow) to fly an airplane at it?s lower limits, until I met this bunch at Supercub.org. In fact, that?s what this airplane is all about.

Please bear with me (and my long post) while I share a story that I hope will make it clear why I think it?s important for a newbie to practice dragging the field.

While my Champ instructor was endorsing my log book for my conventional signoff, he mentioned that he had to give an impromptu speech that evening at a safety seminar and didn?t Know what he was going to say. I suggested that he consider the following.

When landing the Champ, if you break it down into little parts, the real landing phase only lasts about 6 seconds. Think about it.
The phase of flight that I?m talking about here is about the last three seconds of the flair, when (if you?ve done all your work correctly up to that point) you?ve got nothing to do except to just sit there like a pumpkin in the proverbial patch of life, and wait for the touchdown. Now that?s not exactly true, but you get the point.
Plop, you're on the runway. Now for about the next 3 seconds (or so) the inertia is usually enough to carry the airplane in a straight line (if the last phase was correct and the Gods were smiling). After that point, you?re driving, not flying.
Now given that, and given the fact that you can only do about six T&Gs in the Champ in an hour, if we would have spent my whole 10 hours of training, doing nothing but T&Gs, I would have accumulated about 6 minutes of experience at landing a taildragger. However, we all know that you can?t spend your entire time getting checked out in a new plane, just doing T&Gs, so your actual landing experience is considerably less then that.

I really enjoy reading about the advanced techniques (did I get it right that time?) of STOL operations and I hope they keep coming, but it?s only through experience that you gain comfort in your own abilities. You guys with thousands of hours of flight time have got hundreds of hours doing landings....I don?t. But I?m learning.

Is dragging the field, right on the very edge of the stall flirting with disaster? You betcha, in fact, in one way or another, we all do it every time we fly, and I intend to master it....well...I hope to anyway.

Stay tuned for the ground loop stories from Cavy.
 
HA! I love it.

Cavy, I tell my students "Landing is all about the last 11 seconds, and we will spend hours together flying around to get to them".

After your post, I will change it to six seconds! (we do try to land slower..)

sj
 
flagold wrote:
> If you're interested in large aircraft operations in ground effect, you ........... using ground effect. You can catch pics of them on Disc.
channel Wings on seaplanes. <

The big planes are interesting aren't they. I'm more interested in the effect of height above ground (HAG) on a couple of late-Cretaceous azhdarchid pterodactyls. The smaller of the two -- Quetzalcoatlus species, had a wingspan of about 16 feet and flew at a height of about 3 feet when feeding. The larger -- Quetzalcoatlus northropi, had a wingspan of about 36 feet and flew at a height of about 6-8 feet when feeding. These are the only two fresh water skimmers currently known among pterodactyls. Most of the others were marine feeders that didn't make such extensive use of ground effect. Since the effect of HAG on induced drag follows the Biot-Savart law, I usually just calculate the low altitude effects as required by using that. Works for airplanes too.
All the best,
JimC
 
Back
Top