the more technical categories aerobatics doesn’t require endless desperate
nights in the workshop cellar, operating precision power tools, to tune
engines in order to find the last hundredth of horse power or those two
or three revolutions which had been lost recently. We don’t need a
computer aided test bench producing funny power curves to improve our flight
performance. Aerobatics is a flying event, and that’s exactly what
we should do to enhance our skills and our scores ( if we have decided to
take part in contests ). We do not depend on the most modern, most powerful
equipment . We have to develop a finely tuned cooperation between brain
and hand, and this means practice.
|The term “practice” doesn’t always evoke positive associations. Very often practice is considered irksome, monotonous, boring; robbing valuable time, destroying and keeping us from having fun. In these modern times instant gratification is the popular drug. The result of this can be seen every weekend on RC flying fields: awfully low level of flying ( and other ) skills and an ever increasing gigantism to get this desired gratification. What is overlooked generally: there is NO shortcut to success and satisfaction. Whatever we want to achieve can only be reached by paying a price for it. Funny thing: this price needs not necessarily be irksome and boring. It can be pleasant, interesting, and fun.|
is “practice”? First of all it’ flying. After all we’ve
chosen this activity because we like to fly. Making a few flights on a warm
sunny Sunday afternoon is much more fun than burning midnight oil accompanied
by a lathe. Simply roaring around doesn’t make much sense. The essential
contents of aerobatics is flying manoeuvres - and this means some basic
kind of discipline. Discipline is the key word. Without discipline we cannot
fly manoeuvres because a manoeuvre is a discipline in itself. Now - if we
have made some nice flights we have already practised and learned discipline.
Discipline doesn’t mean to execute the same procedure over and over again in a stupid and thoughtless repetition. Discipline requires - or better yet: allows - trying to accomplish a chosen task in order to reach a satisfying level. In this process it may be necessary to change a proven method or a preferred technology. We need to observe, compare, draw conclusions, apply earned knowledge, and eliminate mistakes. We can use practice flights to test propellers, plugs, fuel, pipes, trim etc. This method alone offers enough variety that there’s no cause for boredom, and we can practise with great perseverance. On the other hand - easy, quick, and cheap success can satisfy simple minds only. The effort is part of the way to success and excellence. Brett Buck ( American top pilot ) has said it so wonderful:
“Excellence is a journey, not a destination”. Thanks, Brett. Let’s travel !
Explanations given above do not dictate that practice flights have to be made under all conditions and at any cost. If we absolutely don’t feel like flying it doesn’t make much sense to force ourselves to go. Psychology teaches that we are most receptive when we are in good mood ( TV commercials know how to use this ). Apart from exceptional cases when the situation requires increased effort, our present state of mind may influence our practice rhythm now and then. After an intense quarrel with your boss, your mother-in-law, or the environment people this moment won’t give us enough concentration so necessary for soothing practice flights. Better do some balancing ( props !). Surely we cannot order good mood, but we can prepare for successful training. Apart from a good airplane and a reliable engine, we should have enough time for a decent number of flights. You cannot practise in a hurry. Rush hours disturb concentration, let us overlook mistakes, and causes new ones. We better limit the number of flights. Disturbance caused by Stuka-like RC models, noise, nearby traffic, or pedestrians should be avoided if possible. Flying without a fenced or marked area or at least a watchful helper on parking lots is risky and can be downright dangerous - or how will you describe a situation when after completing three loops a car will suddenly stop right behind your back ( don’t ask how I know ) !!! Despite what I said about sunny Sunday flights : we should try to perform all flights as well as possible. Each flight should be seen as a competition flight. Except for the occasional fun flight with our fun model there’s no sense in playing around unintentionally with our number One airplane.
It goes without saying that we use suitable and comfortable clothes. Some pilots prefer caps with a big shield. We should test whether we like it or not. The shield may limit our view in overhead manoeuvres if our the spine is not so flexible. Sun glasses are mandatory. Extra dark glasses might cause problems when the pullouts have to be flown in the sun with a very dark background ( buildings, forest ). Solid shoes are very helpful. Loose sandals cannot give a safe feeling even on concrete ground. On grass only sport shoes will do. Unevenness like grass tufts or mouse holes can easily rob our concentration.
|The number of continuous flights depends on constitution of the pilot. Three flights, five at most, are considered practical. After that concentration suffers, additional flights will probably be worse and will not be effective practice flights. While still in the beginners phase or during a trim session these recommendations shouldn’t be taken dead serious. But then we don’t call this “practice flights” as seen in context with this story. If at all possible we shouldn’t leave practice flying open to chance. Better to give it some thoughts, decide on a procedure, and carry it through.|
|Talking about procedure doesn’t mean the correct order of manoeuvres only. Beginning with the preparation of our airplane until leaving the flight circle all aspects should be thought through in time. Of course the procedure depends on the respective equipment. For instance, a diesel engine requires other treatment than a glow. And if we always have a friendly helper at hand , the starting procedure will look somewhat different than a solo scene. Whatever has proved simple, practical, and safe will be repeated on every succeeding flight; at least as long as a better method hasn’t been found. That way the procedure is impressed upon our memory, everything runs automatically, saves us to think about each step separately, and will diminish negligence. The trained procedure doesn’t need extra concentration and can save this for the flight. Apart from this - if problems might arise they will easily be noted since they instantly disturb that smoothly flowing procedure. Necessary modifications ( caused by weather or flying field ) can be adjusted to existing experience, carried through, and - if found successful - saved as a variation in our memory ( like, say: engine warm up time and needle setting before the start at low temperatures ).|
always amazing to see that even experienced pilots can make banal mistakes
when under contest pressure. The handle is connected the wrong way, tank
is not filled, battery leads fallen off - there’s no mistake which
hasn’t been made yet. Therefore on those relaxing fun flights on those
lovely summer Sundays we should keep the same routine just as we do at a
contest flight. It starts with connecting lines and handle and marking the
circle centre with a well visible object. Our brightly coloured line reel
is a good means since we can still see it from the corner of our eyes. A
green screwdriver put on the grass is ridiculous ( no joke, I’ve seen
that ). Cleaning the lines before each flight will ease our mind if we suspect
the ground, especially on parking lot concrete surfaces. At the same time
we can place the handle in the correct position. Some pilots like to twist
the lines once or twice before the start. Depending on how they are moving
during the flight the lines are then untwisted for landing. If we use a
stooge we should again check safe anchoring: the stooge on the ground and
the airplane in the stooge. Warned from my own ( admittedly shameful ) experience
I do this check very carefully. All required accessories should be right
at hand now. Finger guard, stopwatch, battery leads, fuel bottle, tachometer,
and what else we feel necessary and helpful. Starting the engine with our
bare hand without protector is extremely careless, simply stupid, and when
using one of those carbon propellers highly dangerous ( a world class pilot
has had all tendons of his right hand cut, thereby preventing him from working
in his profession ). To check the flight time we can use the stop mode of
our wrist watch. With the other stop watch we can check lap times if we
want to have this information. We can check RPM, lap time, and flight time
on each flight and then refer to the prevailing weather conditions. That
way we can collect an invaluable amount of experience. This will avoid further
mistakes, useless flights, and is a big help if practice flights on a contest
are not possible.
Before walking to the handle we should make sure that the battery leads are not caught on the undercarriage. A last check of the connection of the lines with the leadouts is recommended. It can happen that one clip is twisted and turned around, thus in effect making one line shorter. In this case shortly after launch there will be a sudden jolt and our airplane will jump up or down one foot or even more - a sure thing to wreck our nerves. That’s where our helper can really gain a masters degree. We should tell him/her before the flight what to look and watch for. For instance: whether the circle is free of people, whether all fuel tubes are still in the right place, whether the judges are ready. If there’s a battery or a tool box on the flight circle, this might somewhat impair flight performance. The airplane should stand exactly tangential to the circle ( except the pilot has ordered another position ). If not really tangential there can be a bad jerk or even worse action after release. At last it is important to inform the helper precisely about what kind of hand signals we intend to give out of the circle centre, what they mean, and what action he is expected to do. Nothing will look more ridiculous than those desperate attempts of a wildly gesticulating pilot who’s trying to inform his helper to finally let go of the airplane.
strict insistence on following a fixed routine may appear obtrusive. In
my opinion this is the only way to constant performance and success. Only
when a procedure is repeatedly trained and optimized, we can expect with
some probability that on contest day it will work reliably. Also those who
don’t have serious contest ambitions will benefit from their experience
made during practice flights, can be proud on their performance, and will
get more fun out of their activities.
Every aerobatic pilot will freely admit that the engine starting procedure is one of these points which can give him the most peace and self-confidence if it works flawlessly - and which will rob his nerves if it doesn’t. So it makes sense to practise this process. It will vary, depending on engine brand, engine size, engine type, tank system - and of course weather. The basic idea is to provide the engine with all it needs to start quickly and reliably. We try to find out what our engine likes, then we use this method and try to optimize it.
The method includes the way we fill the tank, correct usage of fuel lines
( open or close vents ), the process of fuel priming , acoustic check whether
the engine is ready to start ( Smack! ), applying battery leads; giving
hand signal, check of ampere meter if we use one, flicking the prop ( how
and how often ), removing battery leads ( when ? ), checking engine sound,
removing accessories, checking time used up until now ( to be sure that
in a contest we can be airborne within one minute. If not we might consider
to call an attempt ). While we are walking to the handle in a relaxed looking
attitude we can again check whether the circle is free of people, dogs,
and other obstacles, and do a last check of the wind direction. Then a last
glance at the elevator - does it go up when we give Up - correct deflection
( around neutral on concrete and a little Up on grass ) - hand signal -
I said that I check RPM and flight time on every flight, lap time very often. That way I can gain lots of experience which is immense helpful on contest flights. If you are like me and use different airplanes and engines during the season, you’ll have some difficulty to set the engine by ear. If however you stay with the same equipment for a long time, you’ll be able to train your ear so you can renounce on the tacho. Flight time should be checked regularly. Together with weather observation this will enable us to react on changing conditions.
Knowing and having control over flight time is an important aspect and can be a life insurance should something ever go wrong. If we know when our engine quits we can mentally prepare for that moment and prepare for the landing. Some pilots have mastered this art with amazing precision - they seem to be able to stop their engine at will. Of course this impressive performance is the result of extensive training with the stop watch; this tells us the average flight time. To be on the safe side we can train a certain procedure: after completing the schedule we slightly whip the airplane on normal level to increase fuel consumption. Shortly before the expected engine stop we abruptly fly a steep climb. We want to gain height anyway to get some energy for the landing gliding lap ( required in FAI contests ). In most cases this sudden jump will shake around whatever little remains of fuel are left in the tank, and the engine will quit. Within limits this method allows us to stop the engine in a safe way and help to prevent an overrun. Risky manoeuvres after completing the schedule are not recommended. It doesn’t look very professional at all, and it is very dangerous; many airplanes have been destroyed in the questionable attempt to stop the engine. When the engine has stopped we quickly try to be aware where the airplane is positioned at this moment. This is important to know since we have to arrange the landing manoeuvre. Especially in strong wind we instantly have to decide whether to whip the airplane or rather hold it back. On concrete we can try to touch down with tailwind and with enough speed. Little hint : before the final halt we can apply a little Down. That way wind cannot grab the ( up ) elevator from behind and cause a nose over. In head wind this will keep the airplane from jumping back into the air.
of that gliding lap from motor stop to touch down as required by the rule
strongly depends on the configuration of our airplane. We have to consider
the landing manoeuvre accordingly and to practise an appropriate method.
I’ll not going to deal with precise manoeuvre description and a detailed guide for execution here. This has been done expertly in other places. What follows is some more general advice on how to practise the whole flight schedule. Now the age old question arises: should we practise single manoeuvres separately and intensively - or the complete schedule as a whole.
suppose a pilot is climbing the skill ladder. He has just learned what those
manoeuvres look like and how to move his wrist to reproduce like looking
shapes. There’s no reason why he should not repeat a manoeuvre instantly
after a less successful attempt. The error is still fresh in his mind and
he can concentrate on eliminating it. Also he can compare good and bad shapes
better. Of course he’ll have to keep a watchful eye on the stopwatch
in order to not be caught with a dead motor at the wrong moment. At a more
advanced state however the schedule should be practised as a whole, in correct
order and without changes. Additional aspects will appear, which will have
to be noticed and practised.
We should try to burn the complete schedule into our brain. We’ll do this before the flight, if necessary before each flight. A notebook ( even if a paper version! ) held in the left hand is not considered really practical. After all, remembering the correct order is part of the training and should be practised, too. Looking at a note takes our eyes off the airplane and can disturb concentration. For our first contest adventure we’d better ask a friend to join us in the centre and give some mental support; this will help to avoid shaking knees. But he should call the next manoeuvre only when required. During practice sessions we should renounce this assistance.
As mentioned before we should attentively practice the starting procedure. Long lasting or vain prop flipping will tire our hand and confuse our mind. Precise manoeuvring is not possible any more. Starting the engine “first flip” must be practised. It is possible, looks professional, soothes our nerves, and definitely improves self-confidence.
pilots agree that doing the first manoeuvre well is very important. This
is the wingover. It’s felt a great relief when the straights are straight
and the pullouts low and clean. If we succeed we’ve deserved to praise
ourselves “ Well done, mate! Do it again!” Then we take a deep
breath and prepare for the next manoeuvre. We fly the level laps exactly
as per the rule book. Never less ( this robs concentration and - what should
it be good for ), but not more, either. Those level laps are good for relaxing.
Also we can again check wind direction and speed which helps to decide on
placement of the next manoeuvre. If wind direction keeps constant we may
choose something in the background ( building, tree, mountain ) to serve
as a reference point for our manoeuvre centres or intersections. This is
also good practice to find out where we have to “start” a manoeuvre
in order to get the centre in the desired place. On a contest flight however,
I wouldn’t unconditionally choose the sole telephone mast in the whole
area as my reference point. That would make judges’ work easier than
I might like.
I don’t think that increasing the number of level laps between manoeuvres is a good idea. Usually it’s done to wait for the current gust to calm down. It’s risky to do three or even more. Firstly we don’t know for how long this damned gust keeps blowing. Secondly it can become even worse. Thirdly we cannot continue this game as we please - after all we have to consider flight time and tank volume. It happens all too often that at the end of the schedule we may have enough fuel for another minute. However in the Clover Leaf - or even during Overhead Eight - this little rest of fuel will not exactly splash into that corner where our feed tube waits for supply. This can lead to disaster. We should see additional laps only as a last resort which is used in extreme cases only.
Flying the complete schedule takes 5 ½ min on average, somewhat more at slower lap times. To be on the safe side our engine should run for at least 6 min but not longer than 6 ½ . The landing phase ( from motor stop until stand still of the airplane ) may well take about 15 seconds on concrete; this depends on how well (=long ) the airplane will roll. So after finishing the schedule we usually have a few seconds left. It doesn’t pay to practise more manoeuvres during this time. Especially corners cannot be flown precisely. Because we have used up fuel during the flight the centre of gravity has moved back ; on big and thirsty engines quite considerably. In this trim our airplane is slightly more tail heavy now, and it likes different control input now than what we have practised with a full tank. Those well trained control movements don’t quite fit any more, they produce “wrong” reactions of the airplane. Especially wingovers are very hard to do now. So it doesn’t make sense to practise manoeuvres during this period. Period.
completion of the flight we should relax a few minutes. At least we permit
the engine - and ourselves - to cool down. We can use this break to think
about our errors, about how to avoid them, or about a trim change should
this be necessary.
In an advanced stage of our aerobatic carrier it’s time to think about the influence of weather on positioning the manoeuvres. When placing certain consecutive manoeuvres exactly downwind, some airplanes tend to speed up. In strong wind this can become really uncomfortable since the airplane begins to pull very hard. Now we can reduce the pull of our lines , thus easing the load on our hand noticeably. Certain manoeuvres are not flown exactly downwind, but instead shifted to the right or left. All inside loops have to move to the left ( as seen from the pilot ), outsides go to the right. This applies to the squares, too. In these positions the airplane has to fly the bottom part of each manoeuvre ( as in consecutive loops ) “against headwind” . So ground speed is reduced ( this is what pulls our arm longer ). The same method can be used for the triangles - these are insides . Even the hourglass can benefit a little: on the climb our airplane “feels” less headwind, and the last corner doesn’t suffer from excessive tailwind.
Of course this method of shifting requires a slightly modified control input
at the corners. Round loops require more attention to achieve a nice circle
path. Squares are even more difficult to do. For instance: at the first
corner of the inside square our airplane is really ripped around the corner
and thrown upwards ( the same happens at the bottom right corner of outsides
). If we have never flown that way we’ll be surprised and the manoeuvre
is spoiled. We will have to practise this method in order to use it successfully.
At least I prefer it over getting panic attacks from my airplane speeding
up downwind in a hurricane.
The opposite of storm is dead air, and this is what aerobatic pilots don’t like either. Firstly, in these conditions we sometimes may have problems with changing wind directions ( it’s not actually wind, it’s rising thermals ). Such flights can be frustrating, to say the least. Where ever we choose to fly, the wind always seems to blow into our face and the airplane behaves like a drunken elephant. In those conditions it’s recommended to turn the needle in a little and to fly a little faster as usual. Secondly, in consecutive loops the airplane flies into its own vortex which it has created on the foregoing loop. Since there’s no wind to blow it away, the vortex will stay in its place and can badly throw around our airplane. Sudden jumps of about several feet and excessive rolling can scare us to death ( in such a manner I’ve lost an airplane when it was pushed down five feet in an outside loop ). We should know this phenomenon and be prepared. We can save the situation by walking back two or three steps before we start the next loop, thus preventing to enter the vortex zone. It’s not really that difficult, but of course we should practise it .
In case we’re going to loose or have already lost line pull we should react as quick as possible, and of course it helps if we are ( at least mentally ) prepared for this. There are places in the schedule where this situation can appear. Usually it’s the top of the vertical manoeuvres and the first loop of the clover leaf. Everybody should think about this situation in advance and find a solution to quickly regain tight lines. It’s not possible to give concrete advice here since everybody reacts differently. We should find out what suits us best: pulling back our hand, bending backwards, going down on ones knees, and/or stretching the whole arm backwards. Also it’s possible to catch the lines with the back of the other hand and pulling this arm back, thereby restoring line pull. Don’t be afraid to try - it’s throughout possible to control the airplane “around the corner” respectively hand. At least this gymnastic performance will save it from disaster.
|Pilots trying to enter the range of square geometry very often tend to fly corners much too hard. In an attempt to do a sudden and radical turn , the airplane is forced around the corner without pity. This will create lots of drag, thus reduce speed, sometimes the wing will even stall. The airplane will stagger to the next corner, same violation again, total loss of aerodynamics, panic, manoeuvre destroyed, airplane sometimes too. We’d better start to fly corners softly. With our airplanes the rule radius of five feet can’t be done anyway, so we don’t care about that. Much more important is the proper shape, a clean exit from the corner without nervous jumping, a precise 90 degree angle - and all this four times in succession. This will keep us busy even without sharp corners. If the manoeuvre is flown big, the airplane feels much better, and we have enough time to watch geometry.|
|. We try to produce an exact shape first. This offers the opportunity to observe the airplane’s reactions and to realize what it is capable of and what we can expect from it. As soon as we have control about the shape of the manoeuvre we can begin to reduce the size. Most pilots fly a little bigger than what the rule says. This may cost us some points of the score. However trying to keep the correct size with dogged obstinacy and thereby destroying shape will probably cost us even more points. In very strong wind opening up manoeuvres will often be our only salvation to survive.|
dead calm air we’ll use that line length which our airplane feels
most comfortable with. And in most cases these are the somewhat longer lines.
However we fly a little faster than under ideal conditions ( = soft breeze
). About two tenth of a second less per lap will already re-establish trust
in our airplane ( as can be seen - the stopwatch is indispensable ). In
strong wind we can use a line length reduced by about ½ meter. Of
course we can fight the wind by other means, too; like using another engine
setting, another propeller, changing line guide position. Adding a little
tail weight may not be quite wrong either.
If we have already reached an advanced level we may dare to consider an aspect which in my opinion has been neglected too much. Even some experienced pilots happen to dangle or jerk at a certain place in the schedule. They are unaware of this, don’t see it by themselves, and cannot scratch out this mistake even if told by onlookers. If we find ourselves in such a situation we should look for the reasons. In many cases it is an awkward movement while controlling a manoeuvre. Not all manoeuvres can be flown in a fixed stand with the feet glued to the ground. Depending on our preference some require a sequence of steps or at least turning the body. As a result we loose our chosen reference point or line. Especially some overhead manoeuvres against a clear blue sky impede orientation. Also it’s possible that a change of stance or an incautious step will cause an unwanted movement of our hand. For all these imponderabilities it is helpful that we consider all those steps and turns in advance and lay down a procedure we feel comfortable with. The best method is to do some “dry” training; means: without airplane at home, with our arm stretched out, mentally flying the manoeuvre, thereby watching our body and feet and what they do. We can try several variations of one method and finally decide on one which we like most and which can be used with the least effort ( while doing this it might be advisable to close the curtains before our neighbours consider calling the psychiatrist !). A smoothly flowing sequence of movements will be transferred to our flying. It’s not by chance that the most efficient movements are also the most harmonious ones ( watch cats when they move !). And if our presentation looks a little more elegant, that doesn’t hurt either, doesn’t it ?
As an example let’s take the Wingover. Usually it’s started upwind. During the first half we turn around in order to carefully watch the pullout into inverted. After one half lap we do the same procedure again. During this turning we can easily loose orientation and cannot observe precisely whether the wingovers are exactly straight lines. But we can use a much better version. We simply put this body-turning on the moment before and after the manoeuvre. That means: before beginning the wingover we turn in advance and place our shoulders parallel to the wind direction. This is our reference line now. The whole procedure : climb – pullout – half lap – pullup – wingover – pullout runs without any steps and turning, we have a steady reference line, and we can fully concentrate on controlling. Shortly before the last pullout we may slightly pre-turn the upper part of our body so as to not have the airplane right behind our back after the pullout.
end of the wingover will find us in a situation where the airplane is soon
disappearing to the left. During the manoeuvres most of us are standing
somewhat straddle-legged to have a solid stance and a reference line. Since
we concentrate very hard on the pullout ( after all we don’t want
to miss 1,5 meter ) we sometimes are still in this position when the airplane
has already moved some distance. Now when turning left quickly the left
leg may be in the way of the right one, and I’ve even seen people
stumbling. There’s a simple solution. Instead of starting with the
right foot forward we step BACKWARDS with the left one ! This will yield
a very soft harmonious movement which at the same time helps smooth flying
and looks quite elegant. Of course the same is true for other manoeuvres
as well, and we can find similar steps and movements which suit us best.
Also we should think about what we can do in emergency situations. A typical case is the Clover Leaf. The exit of this manoeuvre is a vertical climb. The airplane has lost speed now and has to fly a wingover against headwind. In strong wind this is an accident waiting to happen. Taking a few steps back quickly and pulling back our hand will be the rescue. HOWEVER we are standing upwind of the centre now. If we do not hurry back as fast as we can during the dive, we will pull out exactly between the judges. I’m sure they didn’t expect to see our performance that close, and the one we hit will not be much amused. A similar situation can occur when for some unforeseen reason the lines had gone totally slack and we had to run for the life of our airplane. In such a situation we find ourselves somewhere in the surroundings. When our airplane has survived we should accustom ourselves to instantly fly high to avoid any unpleasant coincidents with trees, fences, and other unnecessary immovables.
|It’s general usage to slowly walk backwards during launch and landing to keep the lines tight. We should always be prepared that a sudden gust can throw our airplane into the circle. For this reason a solid stance while launching is not recommended. Some pilots crouch down a little and hold their hand low. This way we can better see the attitude of the airplane on the ground - and the elevator! Also the airplane sits more horizontally and will roll on both wheels and not on the outer wheel only, which could lead to unpleasant rocking on launch. I have already|
that I insist on having the airplane sitting tangential to the circle.
This has lead to an experience I’ll never forget. When picking up
the handle with my left hand on a contest flight, I noticed that my helper
was holding the airplane with the nose pointing extremely outwards. With
my right hand I gave a signal to turn the nose in. My helper understood
this signal as “let go”. You know - I’m right handed
!!! Lesson learned.
flying need not be an unpleasant task - “it ain’t necessarily
so”. Imagine a friendly day with agreeable temperature, not too
cold and not too warm. A soft breeze to help keep our airplane out on
the lines. The sun looking in the same direction as the wind so we have
it behind us. We are alone on the flying field with enough time to do
three or five flights without being disturbed by anything. We can take
some relaxing breaks in between for a refreshing drink and we can listen
to the birds practising their clarinet solos for the next Benny Goodman
orchestra show ( “hey, Blackbird, your cue!” ). What more
can we ask for.