Maneuver Techniques and
Judging Pointers
Rudder Control
(Sportsman and Intermediate)
When you first start flying pattern you don’t even think about it. Once
you’ve had a little time in the sport, you start to notice some people never seem to
need to correct their line while others are constantly banking to reestablish their
heading. Well, those that are banking the model with aileron are noticed by the judges,
the other flyers, the spectators, the concession attendant, the horse standing out in the
field and anyone else 
who may be watching. That’s not the way to
correct your heading. Rest assured the pilot that always seems to be on heading
didn’t get there by just having a well trimmed plane and being lucky in his
maneuvers. I once commented to Glen Watson that he never seemed to make corrections. His
response was "I never quit making corrections." He was just doing it in a way
that was less obvious and almost stealth. Glenn won 7 of 8 Intermediate contest he
entered.
OK then, how do I go about making these less noticeable corrections to my heading. It’s that other control that you only use for takeoff and stall turns, the RUDDER. I competed a season without using the rudder to any real extent and placed in the middle of the pack in most contest. Once I started using it reasonably, I started to score much better. This is a necessary control if you want to compete effectively in Sportsman and Intermediate and essential in higher class if you want to keep your shinny pattern plane in one piece. The point is, learn this control when you start and you’ll be far ahead of your competition.
To learn to use rudder, you must have a starting point. The plane does manage to get into some reasonably strange positions sometimes and knowing what rudder to push isn’t always intuitive. Well, it’s almost never intuitive to a new pattern pilot. I’m going to give you a way to think about rudder. It’s not the only way and maybe not the best way, but you have to start somewhere.
Ideally, you want your model to have a pure response to rudder (when you push the rudder, the plane only yaws and does not roll). If you have a computer radio, the mixing functions will take care of this, otherwise you may (will) have to use some aileron to get the necessary response (harder!). Your position in the pilots box is also important. I strongly recommend you stand with your shoulders square to the flight line with the radio’s antennae pointed down the centerline. Assume this position and don’t move for the entire flight. If you move your shoulders during the flight you stand the chance of losing reference to the correct line. This position also gives you the best chance to develop a mental picture of the required corrections.
These suggestions may seem a little mechanical, and they are, but with practice they become easy. Rules:
- Rolling from upright to inverted, the sticks go in opposite direction. Right roll, left rudder; left roll, right rudder. This will always give you top rudder when you are knife edge.
- Rolling from inverted to upright, the sticks go in the same direction. Right roll, right rudder; left roll, left rudder.
- When the line needs to be corrected and the plane is upright, I find it easy to visualize myself in the ####### and push the nose of the plane in the direction it needs to go. Standing square to the flight line makes this easy. If the plane needs to move the nose right, push right rudder.
- If the model is inverted and the line needs correcting, I again go mechanical (can’t seem to get myself in an inverted ####### without going goofy). If you’re coming in toward center, inverted, push the nose in the direction it need to go. If the nose needs to move right, push right rudder. Use your eyes as the direction for the rudder. Your head is turned to the plane so push the rudder toward the eye that would put the nose where you want it. Think about it! Once past center, going away, push the tail in the direction it needs to move. If the tail needs to move left, push left rudder. Push it toward the required eye.
That’s it for the mechanical part. Pretty easy huh? Now let’s put these rules to use and talk about practicing.
- Correcting your line while upright; straight flight out, straight flight back, setting up for and exiting maneuvers, etc. Do a complete flight of just flying a straight line along the path you will use for your maneuvers. Use the rudder coming in and going out while visualizing yourself in the ####### and note the aircraft movement. About a tank of fuel and you should have this down.
- Half Reverse Cuban Eight: You’re always looking at the tail of the airplane when you start this maneuver. As you pull up into the 45 degree climb note the position of the nose as if you are sitting in the plane and make any needed correction. Release the correction and roll inverted, note the tail position and go mechanical. Since you are going away from yourself inverted, push the tail in the direction it needs to move. Do this a couple of times and the correction becomes automatic. This is already getting easier.
- Loops: Starting loops can be visualized just like starting a take-off. When I start a pull up for any looping maneuver I push the nose in the direction it needs to go. As the plane comes inverted, I assume I’m looking at an inverted airplane coming toward me and push the nose the direction it needs to go. Use your eyes as suggested above.
- For Intermediate flyers rolling inverted and upright, try making the rolls a little slower and using the rudder going in and out of inverted. Do this for your straight inverted flight and reverse outside loop. Use the mechanical inputs suggested above for these rolls (don't use rudder for the 3 rolls).
Start all corrections very gently as soon as you notice the need and gently release as quickly as possible. Experience and practice will make a big difference. Burn the fuel and it will pay dividends!
Don Ramsey
Rudder Drills
The discussions on this page came from the web site nscra-list@eskimo.com
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Four of the Sportsman (soon to be Intermediate) center maneuvers can be readily adapted to rudder drills. The objective is to fly them one after another without leaving the maneuver and to be able to move the whole maneuver in and out a prescribed amount. If you have a caller, have her call the direction and the amount of the correction. The easiest is the three loops. Remember to keep your wings level and make the changes with the rudder. Don't forget to pay attention to centering too!
The other three maneuvers useful for this drill are the cuban eight, the reverse outside and the square loop. Get real comfortable with the reverse outside before you use it in a rudder drill. A lot of good airplanes are lost on this maneuver, including one of mine!
It is tough to see the effects of rudder in the turnaround maneuvers, that is why the emphasis is on the center maneuvers.
In actual contest flying a measure of aileron is used to maintain track in both pushes & pulls. This seems to be a popular downgrade to the unschooled judge who takes points for "wings not being level". The only reference for downgrading "wings not level" that I have found is in the avalanche and I think there could be better wording on that. Sometimes getting it right is not enough, you have to be able to fly what the judges want!
John Ferrell
Glen Watson (Editor note: 1998 National Champion Advanced)
Dick Hanson
d'hawk
Double Immelmann
TIA, Don
Don - Good question!
With any wind
blowing it would be impossible for the rolls to end in the same relative position. This is
because with the rolls having the same angular rate of rotation, ie. both rolls would take
the same amount of time to complete, the distance relative to the ground (our
persepective) traveled during that time will vary based on the aircraft's ground speed and
this is not a downgradable item. Dave von Linsowe There are a couple
of interesting points raised in discussing the double I w/full rolls. The easiest
downgrades relate to the centering of the maneuver. The rules say the middle of the double
I must be a centered square. Any wind corrections you make to accomplish that do not
change this criteria. You need to go into the wind far enough so that you can do a 1/2
loop that ends in the same place as where you started you then do a full roll. On the
downwind side you have to start and end the 1/2 loop in the same place. This is where you
were seeing problems. In order to have sufficient speed coming back into the wind to do a
full roll the tendency is to make the 1/2 loop to tight. The result is no square and a
severe downgrade.Seriously:
Rick Allison
Spins (Everything you ever wanted to know and then some)
Here is an email from Stephen Mitchell an aeronautical engineer friend about spins. He has read the emails and gives his learned opinion.
SUMMARY ABOUT SPINS: STEPHEN WROTE.Let me try to explain what is happening with the ailerons in a spin ....
First there are some fundamental things about spins that you need to understand.
A spin can never happen unless the wing of the aircraft is stalled asymmetrically. Just because the wing has stalled does not mean that the complete wing is stalled. In virtually all cases part of the wing will be stalled whilst the remainder is unstalled but flying at high AOA. The assymmetry results from one wing having a greater extent of the wing stalled than the other side. The plan form of the wing (ie rectangular or tapered), airfoil and wing twist etc will influence which parts of the wing stall and which parts remain unstalled.
When an airfoil stalls it continues to produce lift but less than just before the stall. In the stall the air is separated from the upper surface but typically remains attached to the lower surface. This means that the ailerons will continue to effect the pressure distibution around the stalled wing and thus continue to have power (allbeit reduced) to roll the aircraft.
When the aircraft is spinning it is both yawing and rolling ..... think about it. Basically the motion is a supperposition of these two motions. Now we can consider each of these motions separately. Increasing the speed of either the rolling motion or the yawing motion will increase the rate of the spin (with a corresponding change in the attitude of the aircraft in the spin).
The yaw rate can be increased by a number of means: 1. Reduce the mass moment of the aircraft in the yawing direction. 2. Reduce the side area of the fuselage. 3. Reduce the size of the rudder. 4. Apply rudder.
The roll rate can be increased by the following means: 1. Reduce the mass moment of inertia about the longitudinal (rolling) axis. 2. Increase the size of the ailerons. 3. Apply ailerons. 4. Reduce the span (which reduces the aerodynamic damping resulting from the asymmetric lift distribution that developes when the plane rolls).
If you think now about the motion of the coupled yaw/roll that we call a spin if we apply ailerons into the spin (ie stick towards the centre of the spin) then the rate of roll will be increased and the spin rate will increase. The spin will also become more upright (ie nose down).
The converse is true with out of spin aileron (ie reduced spin rate and a flatter spin).
QED Steve.
Point 2.
Spins have three phases, incipient, fully developed, and recovery. The following are excerpts from the Cessna Manual of Flight: The spin is the most complex of all flight maneuvers. There are actually hundreds of factors that contribute to the spinning of an airplane. In a light, training airplane a spin may be defined as an aggravated stall which results in autoration. During the spin, the airplane descends in a helical, or corkscrew, path while the angle of attack is greater than the critical angle of attack. PRIMARY CAUSES a stall must occur before a spin can develop. However, a stall is an essentially a coordinated maneuver where both wings are equally or almost equally stalled. In contrast, a spin is an uncoordinated maneuver with the wings unequally stalled. In this case, the wing that is more completely stalled will often drop before the other, and the nose of the aircraft will yaw in the direction of the low wing. Typically, the cause of an inadvertent spin is exceeding the critical angle of attack while performing an uncoordinated maneuver. The lack of coordination is normally caused by either too much or not enough rudder control for the amount of aileron being used. The result is a cross-controlled condition. If you do not initiate the stall recovery promptly, the airplane is more likely to enter a full stall that may develop into a spin. The spin that occurs from cross controlling usually results in rotation in the direction of the rudder being applied, regardless of which wing is raised. In a skidding turn, where both aileron and rudder are applied in the same direction, rotation will be in that direction. However, in a slipping turn, where opposite aileron is held against the rudder, the resultant spin will usually occur in the direction opposite the aileron that is being applied.
Point 3
My point is...if a pattern plane will spin with "in-direction" aileron, it
should also spin without it, assuming there is enough elevator authority dialed in.
Yes it will spin but at a slower rate......therefore may not look as pleasing to the
judges.
This is an important point about the elevator .. the amount of up elevator available has a significant influence on the spinability.
I have only come a cross a few pattern planes that will do a rudder-elevator only spin. Our current plane designs are too "stable" to remain stalled thoughout the spin using elevator and rudder only.(tend to become unstalled and fly out of the spin as speed increases...or?? not stalled in the first place on entry.). This is because of the problem I mentioned yesterday ... the long rear fuse tends to stabilize and stop the autorotation. That is why your pattern planes don't spin well.
The rudder and elevator power may not be great enough in our usual setups. Yes
The aileron makes the spin look more tighter/narrower and visually reduces any chance of the axis of rotation looking like it will circumscribing a circular path--zero (insipient spin) instead of a vertical line downward. True ....
Point4
I always start the spin rotation with aileron and after 1 turn I remove the aileron and just keep rudder/elevator as the primary inputs. My spin entry is initiated by leading with rudder and then adding elevator/aileron. Keeping aileron in makes the spin accelerate too much. Yes this makes a lot of sence as it is during the initial transient phase of the spin that you need to accelerate the mass of the aircraft.
Point5
Late last year (before winter) I experimented entering a spin by coupling the elevator with upward going ailerons (I call this reflexing the ailerons). Consequently I made two observations, (1) the nose of the aircraft pitched upwards with less elevator than if the ailerons were not reflexed (should add that use of the throttle allowed the perceived altitude of the plane to be maintained even though the nose was pointing upwards) I would expect this in most situations .... (2) because the airplane had a relatively high angle of attack, speed for entering the spin could be controlled better, i.e. center was not over shot before the plane had sufficiently slowed down to it's stall speed. Yes the elevator had more power due to the reduction in wing pitching moment.
Hanns Limm
A well balanced airplane will stall straight ahead however, the airplane will spin using just the elevators. Maintain the altitude as the airplane slows to the point of stall (Velocity Stall or Vs). When at stall speed the elevators are at it's full input and in this configuration, the rudder only determines the direction of the spin. Applying aileron to initiate the spin simply accelerates it's entry (wing not at full Vs) and the plane would spin at a higher airspeed. I suggest that on sunday at the field you try it. The recovery from either spins will be quite obvious. As a matter of fact chances are that the "no aileron" spin could cause a secondary stall and spin in the opposite direction if recovery is too early, just remember that you would require a little more recovery air below than you would for the "on aileron spin".
I never ever suggested that ailerons not be used to initiate a spin but, from the original post the question was "why does my airplane not spin"......... NO STALL NO SPIN......... Snap rolls are spins...... Air speed = ZERO = STALL.
Mike deFreitas
This has certainly been a good discussion. I suppose that the only way not to have judges with differing opinions is to not have spins in the pattern. One thing that hasn't been mentioned that might be useful. When training judges, I demonstrate to them what elements flown improperly look like. First grossly, then more softly. For spins the gross errors demonstrated are a snap into, a spiral dive, a down elevator "stall" with vertical barrel roll, and improper number of turns. The softer error demonstrations involve an "impatient entry" where aileron is applied early in the stall and flips the wing over the top, an entry where the stall occurs but the aircraft unstalls due to late rudder input then spirals for some rotation before breaking into a spin initiated by the retreating wing again stalling, early spin termination with roll to heading. And finally a demonstration of how the spin appearance may vary with different amounts of control inputs, both with and without aileron, and yet meet the definition of a spin. I disagree with the participants who've argued that certain control inputs negate any possibility of a spin being a spin. If it looks like a duck -- you know the rest. Would the same folks zero a roll that demonstrated improper aileron differential or mistimed rudder application? The role of the judge is to provide a critical review of the way the aircraft performs a maneuver basis the rule book description, deducting points for transgressions. The dynamic nature of pattern ensures will always be some differences in judgment and interpretation, however, participation in these type discussions and formal judging forums go a long way toward agreement. Thanks for the participation. Earl Haury
To add a bit to this thread, IMHO. Forgive me for the rambling in advance - several items/comments in this thread have sparked my interest - R. Ames wrote: > Coming out of the spin a half turn or so early and doing a "wobbly roll" to > finish > it off sure makes for a precise exit and is hard to discern; so does doing > a > "wobbly roll" the whole way down. Are we going to ask judges to learn to > distinguish between spins and "wobbly rolls?" Same applies for snaps.... Agreed. It can often be hard to discern between a true spin and a wobbly roll. However, there are primarily two things to look for to see if the exit of the spin is being "cheated" 1. IF the plane is flown out of the spin to make the exit easier, it will transition from a stalled conditioned to a non-stalled condition - which means the angle of attack will become reduced - the change in pitch is a giveaway that the plane is no longer stalled and no longer spinning. The applicable downgrade would be 1 point per 15 degrees of rotation that the plane was not stalled. A half roll exit from the spin would equate to a 12 point downgrade (and IMHO, I see this fairly often). 2. If the plane is flown out of the spin, the rotation rate generally changes - it usually slows down a little bit and is then constant again until the rotation is stopped. Planes that are borderline on the CG location and have borderline amounts of elev and rud throw will often oscillate between stalled/non stalled conditions during the "spin" - often easy to spot as the rotation rate changes. Items 1 and 2 are useless criteria in the instance that the plane was never stalled and never actually entered a true spin (and IMHO, I see this fairly often). FWIW - as a judge and a pilot, I am very strict on spins (and snaps). The three most recent pattern planes I have flown in competition were a Prophecy, an Ariel, and an Elan. All three would stall with the application of elevator only. All three would spin upright and inverted with elev/rud only. All three maintained a constant rate of rotation during the spin. All three used 45 degrees of rudder throw. The Ariel and Prophecy needed (IMHO) a full 30 degrees of elevator throw to consistently stall on entry and stay in a true spin. The Elan used 35 degrees of elev. IMHO, the Prophecy was the hardest to consistently get into a nice spin entry - and not coincidentally, it also has the longest tail moment - which gives the plane extremely good lock in pitch (no surprise, just a design compromise). I believe that any conventional configuration plane (I haven't flown all of them) will stall and enter a true spin with the application of elevator and then rudder - given enough control throw, and a CG that is far enough aft. The well designed and setup planes will do this without overly compromising pitch and yaw stability in normal flight regimes. The application of aileron during a stall entry, a stall, or a spin may or may not have an effect on the plane - depends on many of the design aspects and setup of the plane. It is certainly possible to force a plane into a true spin with the use of aileron, and, I have seen some planes that transition from a true spin to a tight spiralling roll when aileron is introduced. A hypothetical situation to think about (because I would never advocate standing underneath a spinning plane) - If a "spin" were viewed from directly underneath or above the plane, would it be easy to tell if the plane were in a true spin?? I think so. If the rotation of the plane is about the spinner (or roll axis), then the plane is not stalled, it is rolling about the roll axis. If the rotation of the plane is about the yaw axis (should be very close to the CG), then the plane is in a true spin. Regards, Dave Lockhart
An input of aileron in the direction of the rotation will change the spin to a vertical roll. Bill, I am sure you are well intentioned but the above statement is just WRONG. Control position is NOT a criteria for judging - maneuver performance is. I have never seen an airplane that can recover from a spin by adding aileron INTO the spin. You won't find it recommended in any full-size aircraft manual that I've seen. It may be possible to overpower a spin with ailerons but I've never owned a pattern plane where this is the case. At any rate it is 100% wrong to state that "any input of aileron will turn a spin into a vertical roll." Control position is NOT a criteria for judging - maneuver performance is. My Oly spun best with about 20% aileron into the spin at onset, then completely released. My Desafio will UNSTALL if the ailerons are released entirely, but does beautiful spins with about 30% aileron (in the direction of the spin) held throughout. Now, in either case I'm sure that I could increase the elevator thro to spin without any aileron input, but I don't use switches or rates and see no need to since the added drag from the ailerons does the trick just fine. Just FYI, the Desafio will not go into a flat spin upright, no matter how slowly I cross the ailerons nor what I do with elevator/throttle. (It just stops spinning and falls into a spiral dive). The Oly, OTOH, did great flat spins as long as I crossed the ailerons very slowly and left full up-elevator in. If using ailerons helps initiate or maintain a spin then USE it. Control position is NOT a criteria for judging - maneuver performance is. Likewise, if whatever you are doing allows the plane to unstall during the maneuver, quit doing it! d'hawk
Judging Spins
One point of contention is that of zeroing the maneuver if a wing comes up rather than the fuselage dropping away from the horizontal plane.
As a judge, I admit to being a little generous here. If I am not certain, I cannot take a point for that fault. If the judge beside me calls it a zero because of the entry, we are only guilty of "best effort".
Personally, I think a zero for an entry flaw is too harsh for any maneuver. If it cannot be judged constantly the maneuver is too subjective to be scored at all!
I think a point of contention is whether the track should be maintained entering and exiting the spin. An example would be holding a 15 degree entry angle and exits on a parallel heading to flight line. Did he do 360 degrees of rotation? Should he have entered straight or should he have exited at the same angle to the flight line? I think that the stall is very hard to tell unless you have a lot of experience watching that plane, whether or not someone forced it in. Though I think it is very easy to tell if it is not spinning or comes out of the spin. This is my two cents worth. :) Nemesis
I think these items need to be addressed: 1. Nose High -- I've heard several folks say that they can't make their plane stall decently without climbing. What is the downgrade criteria if it does climb? Gene Maurice made another excellent point in his post. See #3 below.
2. Wind correction during the spin. NemesisRC@aol.com (what's your name, friend??) raised this point in his post this morning. I want to see something put in writing so that everyone had the same understanding.
2A. What is the correct judging if it is necessary to hold a large crab angle for wind correction while approaching the stall? Do we stall at the crabbed angle, or rotate the plane back to parallel with the flight line just before the stall?
2B. Based on the answer to 2A, what are the downgrades? Do you start counting the number of turns from the the crabbed angle, or do you start from parallel to the flight path?
I think counting from the flight path is correct since the number of turns should represent the number of rotations _*relative to the flight path*_. My personal judging criteria has always been that a correct spin is one that _*Maintains Wind Correction*_ throughout the entry and exit, regardless of the crab angle. It impossible to maintain wind correction during the actual spin, since by definition the plane must be stalled. Wind correction on the down line after the spin is done with rudder (just like a stall turn), then a crab angle established on the horizontal exit leg to maintain wind correction.
I would propose the following:
Number of turns is relative to the flight path. Crabbing during the spin entry for wind correction is not a downgrade. Rotation must stop with wings perpendicular to the flight path after the required number of rotations relative to the flight path. Over or under rotation - 1 point per 15 degrees.
3. What actually constitutes a stall? Gene Maurice made a good point in his post - planes stall differently, and most judges do not have experience with every type of plane. I was told by one contestant judge that he wants to see the plane "quiver" before the stall. Sorry, but my middle-aged eyes don't see that well any more, especially at 150 meters. Clarification is also needed concerning whether forward ground speed during the stall constitutes lack of a proper stall. Anybody out there ever done a stall in a full-size airplane? Stall speed is NOT zero airspeed. In a Cessna 150 for example, it's about 50 knots. Unless there is a corresponding headwind of equal velocity, there WILL be forward motion of the plane relative to the ground during the stall. 4. Snap Entry: I like Mike Dunphy's definition. It's easy to remember and apply: "If the wing passes through vertical before the fuselage passes through horizontal, it's a Snap Entry -- zero. Write it down.
5. Push over entries: I've seem many folks (including several big "names") do this at the Nats and Team Selection, among other places. Seems they are concentrating so ####### centering that they blip in down elevator to simulate the stall break exactly on center. They fly a straight down line for a short distance, then commence the spin. Sorry, but that is a zero in my eyes, because if the plane is flying a straight down line, it can't possibly be stalled. The only way to get it to spin from this attitude is to SNAP it in.
That's all I can think of for now, Bob. -- Exiting the Box! Jim Johns,
To add a bit to this thread, IMHO. Forgive me for the rambling in advance - several items/comments in this thread have sparked my interest - R. Ames wrote: > Coming out of the spin a half turn or so early and doing a "wobbly roll" to > finish > it off sure makes for a precise exit and is hard to discern; so does doing > a > "wobbly roll" the whole way down. Are we going to ask judges to learn to > distinguish between spins and "wobbly rolls?" Same applies for snaps.... Agreed. It can often be hard to discern between a true spin and a wobbly roll. However, there are primarily two things to look for to see if the exit of the spin is being "cheated" 1. IF the plane is flown out of the spin to make the exit easier, it will transition from a stalled conditioned to a non-stalled condition - which means the angle of attack will become reduced - the change in pitch is a giveaway that the plane is no longer stalled and no longer spinning. The applicable downgrade would be 1 point per 15 degrees of rotation that the plane was not stalled. A half roll exit from the spin would equate to a 12 point downgrade (and IMHO, I see this fairly often). 2. If the plane is flown out of the spin, the rotation rate generally changes - it usually slows down a little bit and is then constant again until the rotation is stopped. Planes that are borderline on the CG location and have borderline amounts of elev and rud throw will often oscillate between stalled/non stalled conditions during the "spin" - often easy to spot as the rotation rate changes. Items 1 and 2 are useless criteria in the instance that the plane was never stalled and never actually entered a true spin (and IMHO, I see this fairly often). FWIW - as a judge and a pilot, I am very strict on spins (and snaps). The three most recent pattern planes I have flown in competition were a Prophecy, an Ariel, and an Elan. All three would stall with the application of elevator only. All three would spin upright and inverted with elev/rud only. All three maintained a constant rate of rotation during the spin. All three used 45 degrees of rudder throw. The Ariel and Prophecy needed (IMHO) a full 30 degrees of elevator throw to consistently stall on entry and stay in a true spin. The Elan used 35 degrees of elev. IMHO, the Prophecy was the hardest to consistently get into a nice spin entry - and not coincidentally, it also has the longest tail moment - which gives the plane extremely good lock in pitch (no surprise, just a design compromise). I believe that any conventional configuration plane (I haven't flown all of them) will stall and enter a true spin with the application of elevator and then rudder - given enough control throw, and a CG that is far enough aft. The well designed and setup planes will do this without overly compromising pitch and yaw stability in normal flight regimes. The application of aileron during a stall entry, a stall, or a spin may or may not have an effect on the plane - depends on many of the design aspects and setup of the plane. It is certainly possible to force a plane into a true spin with the use of aileron, and, I have seen some planes that transition from a true spin to a tight spiralling roll when aileron is introduced. A hypothetical situation to think about (because I would never advocate standing underneath a spinning plane) - If a "spin" were viewed from directly underneath or above the plane, would it be easy to tell if the plane were in a true spin?? I think so. If the rotation of the plane is about the spinner (or roll axis), then the plane is not stalled, it is rolling about the roll axis. If the rotation of the plane is about the yaw axis (should be very close to the CG), then the plane is in a true spin. Regards, Dave Lockhart
I would certainly buy the "rotations relative to flight path" concept. As I mentionned before, I have always been asked to "straighten up" before the break, which looks stupid, but it's what judges wanted. As for the defintion of a stall, yes I agree. Having been signed off for full-scale aerobatics in my tender years, I can vouch for your observation about forward speed. On the other point, I would challenge anybody to see the "quiver" or stall buffet on a pattern plane. Even when you are INSIDE the plane, you can feel it more than actually SEE the buffet on the wings. The only time I ever "saw" the buffet was in a full-scale sailplane that had metal wings and at the buffet you could see the metal "shimmer" out near the tips. But on a pattern plane at 150 meters? Gimme a break...(no pun intended) John Ford
a)All planes(except Burt Rutan's stuff) will have a pitch down break. The speed(or angle of attack) required for that to happen will vary from plane to plane. Also, the elevator deflection required to achieve that angle of attack is a factor. Most of the time one or the other of these factors is missed by the control setup, or the pilot's technique. I haven't seen an instance where this couldn't be fixed. Sometimes, a faster rate of deceleration can do it, but with the appearance that the plane is climbing, which isn't good(at least to my eyes). b)Even though there is a crosswind, I was raised to believe that the plane must be tracking straight at the moment of the nose-down break, otherwise the "one point for 15-degree rule" kicks in. The nose MUST fall BEFORE the wing raises one way or the other. c)Attitude and track while in the spin doesn't count, but the spin recovery must be executed so the plane is tracking STRAIGHT down for a visible line. This is sometime dicey for planes that tend to spin flatter than others. Obviously, I downgrade "1 for 15" if the wings aren't on correct heading at the moment of recovery. Good topic! John Ford
I have a couple cents to send in here Jim. 1. Nose high.....Well it states near horizontal track, and after the spin Near vertical track. This says to me yes it can climb and yes the line after recovery does not need to be straight down (90 deg to terra firma). 3. Stall speed and zero ground speed I totally agree this also means that from physics the spin may not be vertical. it can and will drift with wind or forward momentum. This would have to be the case cause the plane ain't flyin' only one wing panel is lifting. The big question then comes on center. Is center the break and then the spin can drift left or right, in or out. The picture in the rule book show a bam straight down 3 turns and the straight vertical then recover. I think a note should be put in the rules under the downgrades to clarify this. 4. I also like Mike's definition easy to understand. Some airplanes stall by dropping a wing but the other wing does not come, merely the right wing falls as does the entire plane. I think the key is that the other wing in this case the left doesn't go up and over. Mike's description explains it very well. Just my thoughts on the spins enough discussion last year at the NATS I know. Troy Newman
In the pilots meeting at the 97 NATS it was determined that an entry into to a spin could be crabbed into the wind to hold the line. The pilot that rotated the plane back to parallel with the flight line just before stall, would be rewarded for it. Rick Sweeney
Some things to try are: o Move CG forward o Pull nose up higher o Believe it or not, it can help to pull up the nose less. o Switch in aileron flap prior to stall and disengage at stall point to get a stall. (Allows you to lift nose higher without climbing or using more power. o Last but not least the famous Canadian down elevator stall. Hope one of these works for you . Regards, Eric Henderson