Ted Fancher wrote:
Some fresh thoughts on “Where/How to look while flying”
(FYI, I've no idea how the "strikethroughs" in most of what follows got there as they weren't in the original I cut and pasted. Couldn't find a way to eliminate them. Hopefully, if you're interested enough to read it you'll be able to do so. sorry)
There was recently a thread on Stunthangar with the above title in quotes. I found one post in particular that triggered some thoughts of my own which I felt might be of value for Uncle Jimby’s Stunt Clinic. Dan McEntee wrote the following text which caused me to realize that, my gosh, that’s the way I’ve flown stunt my whole life! I’ll then amplify on why what he says may be valuable to others. Further, why its importance may lead students of stunt to better understand why so much advice you hear from the world’s best stunt pilots has to do with pilot posture and aircraft/powertrain trim!
Here’s what Dan had to say:
“When you drive a nail in with a hammer, do you look at the hammer head or the nail you are hitting with it? When you drive a car…do you look at the hood of the car…or do you look where you want to drive and steer the vehicle where you need to go?
…A well-trimmed model and confidence in its performance help
…When I am flying at my best, I can "see" the shape I need to fly as I approach the maneuver, then I just trace the shape with the airplane
...More than one airplane has been written off [due to] looking at the model and trying to time the pull out…”
To Dan’s mental images of nails and vehicles I’d like to add another task we’ve likely all performed at some point in our lives without a lot of thought; one we might need to think about to realize. A task I feel is very much a template for what excellent fliers do--maybe without ever thinking about it--when they fly those flights that make us all wonder…”how the heck does he do that!”
We’re going to Visualize drawing pictures with chalk on a blackboard!
In fact, we’re going to draw pictures of circles and squares and triangles and think, maybe for the first time, about how we do so accurately! Then we’re going to talk about how to make that stunt ship feel as close to us as that piece of chalk so we can as easily draw those same figures 60 to 70 feet in front of us! How we can do so without giving the ground more than a passing thought as it intrudes on our field of vision, five feet below our airplane.
When you stand in front of a blackboard with a piece of chalk in your hand do you concentrate on the point at which the chalk meets the board as you attempt to draw a circle? If so, what are the chances you’ll draw a truly round circle coming back to finish at the exact same place you started it? How big will it be? How about a square? A triangle? How about drawing a second or third figure exactly overlaying the first after some cretin erased the previous ones?
No, we don’t do that. We first visualize the figure we want to draw in the space before us and then, utilizing primarily peripheral rather than narrow focus move the chalk so as to duplicate that mental image and space. We do so knowing that the figure we’ve visualized has a top at “X” degrees and a bottom just about shoulder level. As long as we follow that correct visualization of the path prescribed by the rulebook the resulting figure will be very accurate and miss the “ground”…by five feet, our shoulder height.
Now, most of us could draw pretty darn good stunt figures on a blackboard naturally. We would look at the board to see how big a loop, for instance would fit into the available or defined space and where it would have to start and end. We would pick up the chalk and hold it naturally like a fat pen or pencil and, using primarily peripheral focus start the circle at the beginning point and, forgetting the chalk, draw a track that matches the demands of the defined space concentrating primarily on keeping the track on the required radius to make it round and finish where it started. When you get back to the start you’ll essentially never have looked at the chalk itself.
You’ve visualized what needs to be done and done it by following the track required to do so; not the implement (chalk or stunt ship) that is following the correct path you had visualized. With the chalk you’ve given zero thought to how you’d follow that visualization, you’ve simply stood at board and moved your hand around a constant arc beginning at roughly shoulder height (more or less five feet for most of us! How fortuitous) and peaking out at the predefined top of the visualization. In order to get to the top you’ve had to raise your hand to that point, thus lifting it to, oh, let’s say, 45 degrees or so. It is so simple to do you’ll quickly ask why can’t I do the same thing with that danged Nobler!?
The important thing to realize is that, in order to fly correctly sized and accurate patterns, a great pilot visualizes the shape of each maneuver within the spaces required by a rulebook pattern. He does NOT focus on the airplane. The airplane is merely the chalk over which he has equally predictable inside and outside control and response so as to allow him to “draw the shapes required within the spaces allowed.” Just as he would do with that piece of chalk on a blackboard. Missing the ground is a natural result of doing so…as are proper shapes.
By now many of you are asking how Ted can suggest that drawing with a piece of chalk is remotely like steering a recalcitrant stunt ship through a rule book compliant difficult maneuver like a square eight or a four leaf clover. “The chalk, unlike my stunt ship, is easy to control and move where it needs to be moved. Not the same thing at all!”
The answer to that question is that before a helper lets go of that super stunter for an official flight the pilot/builder must have “trimmed” that airplane and his own physical relationship to it when airborne so that the airplane reacts as predictably to well measured and consistent inside and outside inputs by the pilot as does a piece of chalk held in his fingers in front of his body. That is the reason why, when asked how ambitious new pilots can improve, top pilots speak endlessly about aircraft/powertrain trim and the physical relationship of the pilot’s body and hand with reference to his aircraft.
We must understand from the beginning that the pilot and his physical relationship to his airplane are part and parcel of trimming the aircraft. The simplest way to illustrate this is to discuss the pilot’s posture and handle position when performing level flight or maneuvers. What I intend to do is discuss what I feel is correct and not try to prove or disprove the endless number of “yeah, buts…” that always arise over the subject. Each opposing point of view would consume as much ink as these several, already too long, pages.
General Comments
The airplane should be in front of the pilot in level flight.
The handle should be a symmetrical shape (i.e. EZ Just Hot Rock or similar shaped) and held vertical…with no “down” bias of the grip at neutral. Remember, the handle is part of the airborne control system on which you worked so hard to achieve up and down mirror image mechanical relationships. Don’t screw it up by biasing the only part of the control system you can hold onto.
The handle should be held at shoulder height roughly in the center of the pilot’s body so that it is between the pilot’s dominant eye and the airplane.
Muscular tension must be avoided. The pilot’s flying arm should be flexed slightly at the elbow and wrist so that there is a shallow “V” between the shoulder and the handle grip. (the use of these “lever hinges”, the wrist, elbow and shoulder, will be discussed in the next section on Maneuvers.)
The vast majority of pattern inputs should be provided by wrist (major) and finger (fine tuning) inputs. The elbow may occasionally be used to emphasize an input but the shoulder should be almost exclusively used to place the handle in the appropriate position with respect to the airplane, raising as a maneuver climbs and vice versa. Using the shoulder hinge the handle should be tracking the airplane, tracing a smaller version of the shape of the maneuver being flown “large” by the airplane.
Avoid large sweeping types of inputs and large, abrupt use of the elbow and/or shoulder to fly maneuvers. If you can’t do the maneuvers using the smaller levers discussed above pay close attention to and explore the suggestions in the final segment of this paper on proper flight trim. Inputs driven by large motions are, by definition, imprecise due to the time elapsed to make the input and the resultant inability to precisely control, for instance, the angles of cornered maneuvers.
VERY IMPORTANT! YOU SHOULD FLY EACH MANEUVER SO THAT THEY APPEAR TO YOU AS THEIR NAME DESCRIBES THEM. BECAUSE YOU ARE IN THE CENTER OF A SPHERE ALL POINTS OF ITS SURFACE ARE EQUIDISTANT FROM YOU AND, THUS, AS FLAT AS A BLACK BOARD SURFACE WITH RESPECT TO YOUR VIEW OF THEM. TO YOU ALL ROUNDS SHOULD LOOK ROUND, SQUARES SHOULD LOOK SQUARE (EQUAL SIDES AND ANGLES), THE TRIANGLE SHOULD LOOK EQUILATERAL (EQUAL SIDES AND ANGLES) ETC. “DO NOT”ATTEMPT TO ADJUST THEIR SHAPE BASED ON WHERE YOU THINK THE JUDGES ARE VIEWING THEM FROM OUTSIDE THE CIRCLE. YOU “SIMPLY” FLY THE TRICKS SO THEY APPEAR CORRECT TO YOU AND “TRUST” THE JUDGES TO DO THEIR JOB.
Maneuvering
First of all our discussion of maneuvering will assume a well-trimmed airplane. We will discuss aircraft trim last as you may find it hard to understand how merely visualizing a correct maneuver makes it possible to actually match that visualization with a misbehaving machine. Read the following as an enticement to pay close attention to what a well designed, powered and trimmed stunter is capable of doing!
Now let’s get back to chalk and blackboard analogy for a bit so we can discuss maneuver placement with respect to our body.
With the exceptions of takeoff and level flight, the wingover, inverted flight and landing all maneuvers should be flown centered on our body which then becomes the reference from which the pilot visualizes the shape and space for the rest of the maneuver. Thus, inside and outside loops, inside and outside square loops, triangles, vertical eights and hourglass will have half of each “loop” to our left and half to our right. The horizontal round and square eights, the overhead eights and the four leaf clover will have all their inside loops to your right and outsides to your left and, thus, your intersections directly in front of (or on top of) you.
The technique to position yourself for most of these maneuvers is the same: on your first level lap between maneuvers you will decide where the center of the next maneuver should be, generally downwind. As you approach the end of the second level lap take one larger sidestep into the lap, plant first your forward and then your trailing foot thus getting slightly ahead of the airplane and then wait for it to fly into your “frame” for the maneuver. (Note that some maneuvers must be started prior to stance center, horizontal eights, four leaf etc. and some beyond stance center i.e. inside and outside square loops). All such entries are consistent with the total maneuver being visualized and centered on stance center.
That “frame” will be the visualized space into which you will draw the appropriate maneuver with your airplane the same way you would with the chalk on a black board. Ideally, this “frame” will be a rulebook sized square for each of the loop segments in the particular maneuver, i.e. the aircraft will “track” each square maneuver side and just “touch” the center of each side on round segments. (If you’re not yet ready for rulebook sizes, be smart and visualize a frame size consistent with your current ability to do the shapes correctly…”shrink” when able!)
You will “draw” the maneuvers within the frame primarily using wrist and finger inputs to establish the correct radius (and/or straight line for cornered maneuvers). Just like drawing with chalk, however, your other “levers” must come into play by tracing the appropriate “shape” with the handle as though drawing with chalk; using your shoulder and elbow to keep the handle tracking a smaller version of the track the airplane is following…you might think of the handle as being the near end of the chalk and the airplane the far end that is tracing the maneuver for the judges.
Then you track your hand/handle around the desired path of the maneuver so you maintain the same angular relationship between the handle and the plane, the desired arc will be maintained with only an occasional adjustment as necessary should the airplane’s track deviate from that you’ve visualized. You will notice such small deviations because you will have mentally visualized the desired shape within its required space and will have a valid reference for an appropriate adjustment. Like chalk on the blackboard in front of you.
A well-trimmed airplane directed as described above will follow your visualized track because consistently repeated control inputs will result in consistently accurate and predictable responses of the airplane to both up and down inputs so as to conform its path to that visualized within the space allowed. Which brings us at last to:
Trimming tips for consistent response to inputs
(Note, we’re not going to cover the basics of trim here…the wings level sort of stuff. All of you are well versed on the basic “musts?. We’ll deal primarily with factors that facilitate flying visualized patterns)
An airplane “capable” of flying visualized patterns with inputs as described above is a must. First the design itself should be such that a few fundamental trim settings are possible.
First it should have an adequate tail volume to allow the Center of Gravity to be close to 25% aft of the leading edge at its MAC (for practical purposes 25% aft of the leading edge, including flaps at that point, halfway out each wing. A good rule of thumb is to insure the tail area is at least 25% of the wing area. (Make first flights with the CG of such a ship at 20% and, if stable and controllable in the glide move it aft a little at a time until control in the glide just starts to suffer…then forward to regain that control.)
The reason for this ~25%MAC CG is that that is also the point at which the lift developed by the wing is centered. Having the CG at or close to that point reduces or eliminates many aerodynamic consequences of forward CGs that negatively affect input responses when less than good conditions—wind, gusts, turbulence, etc.—are encountered. The need for dramatic (and unpredictable) trim changes in response to flight conditions between ideal and awful are minimized. The response rate will remain consistent and the tendency of the airplane will be less inclined to accelerate and, thus, open up in consecutive maneuvers in high wind, etc. You will “NOT” run out of elevator.
Second, all hinge lines must be sealed to produce consistent response. Flaps should have no greater chord than necessary (20% of the total chord at any point on the span is a good limit) and elevators should make up less than 50% of the tail chord; stab to elevator splits of 55/45% or 60/40% provide equivalent elevator authority with no down side. The reduced flap and elevator chords are primarily to reduce hinge moment and, thus, the amount of muscle it takes to make the consistent inputs best suited to the style of flying we’re discussing.
Third, your stunter needs to have a consistent power train that provides adequate but not excessive line tension to minimize the need for lots of muscle to make the tricks happen. The style of flying described in this document requires finessed inputs…not big biceps. Most modern power trains are compatible with lower pitches and higher revs, which will generally result in more consistent airspeed and, thus, more consistent response to control inputs. Take advantage.
Fourth, take advantage of the improved pitch control provided by the aft CG and larger tail volume by insuring you’ve utilized the adjustability on your handle to fine tune the amount of handle input necessary for flying the smallest and most accurate pattern of which you are capable at the time! You will likely find that a properly trimmed ship will require less control deflection and, thus, line spacing at the handle may well be reduced from that required with a more forward CG. Find a combination of response rate and handle input that gets the job done while satisfying the goal of making most of your inputs with the wrist and fingers while following the airplane’s path with the afore described miniaturized maneuver path of your handle (watch Brett! If you “ever” see him throw his flying arm around like a disco dancer call the EMTs because he’s going to need their services!)
One necessary disclaimer. All the above is based on IC powered aircraft with which the author has some experience. Please note that the CG locations discussed are “dry” with no fuel on board. We do not takeoff with the CG at the same location as we set the airplane up. The CG moves slightly aft and response rates increase as fuel is burned out. This is not a bad thing since the maneuvers become more demanding as the pattern progresses. Set up as discussed (in particular with the larger tail volume) the change in response throughout the flight is not dramatic. The smaller the tail gets with respect to the wing area, however, the more dramatic will be the response change. Another good reason for large % tails.
An Important proviso for Electric Stunter fans
It’s been frequently noted as they are refined that more forward CGs and more leadout sweep are desirable on electric powered stunt ships. I don’t understand why but I respect the opinions of those who advocate them. I do know that all but one of the electric powered ships I’ve flown had too much line tension to suit my described style of flying and thus, might not be best suited to those who fly planes trimmed in that fashion.
Fly Stunt
Ted Fancher
I requoted the entire thing. This is the same issue you had before, get rid of the square brackets around the s in this sentence:
…A well-trimmed model and confidence in its performance helps
which is creating the "strikethrough" HMTL tag and causing all subsequent text to be shown as strikethroughs.
More or less, you cannot use square brackets anywhere in the text fields or you run the chance of them turning out to be legitimate HTML tags and doing things like this.
Brett
Topic: Some fresh thoughts on “Where/How to look while flying” (Read 800 times)
