The small mikrokopter flight school Introduction

Prior RC flying experience will determine how to proceed through flight training on the MK. It is perfectly possible to have your first RC flying experiences with a MK. To avoid unnecessary damage and disappointment you should consider practicing on a flight simulator first such as Free Model Simulator (FMS) for which models of the Draganflyers and the Mikrodrone are available. Make sure you spend enough time to go through all the steps of flight training on a simulator first. See [FlugModellSimulator]. To master basic flying skills usually requires between 12 and 24 hours offlight training time . Only progress to aerobatic skills after you fully master basic flying.

If you already have basic RC flying experience with airplanes (ability to confidently fly patterns and perform spot landings or hand catching, but no extensive aerobatic and no 3D flying experience) and limited or no helicopter experience it is best you still go through all the steps of basic flying. Control reversal is much more pronounced with helicopter- like aircraft compared with airplanes. Flying "nose in" (with the front end of the MK towards you) is a skill that requires more practice than flying an airplane in for a landing or pass. It may still take 6 to 12 hours of airtime to master hovering ad nose-in flying.

If you have extensive prior RC flying experience with airplanes (3D flying) but no helicopter experience or some co-axial helicopter experience, you can probably progress through basic flight training very quickly. Even then it is still a good idea to follow through all steps, but most likely each exercise will only have to be done once or twice to get a feeling for how the MK responds to control input.

If you have extensive RC flying experience with helicopters you can probably skip through the basic flying school and go to aerial photography or aerobatics flying straight off if that is what you want to do.

First Steps

The very first step is to think: SAFETY FIRST!

A MK is not a toy. It is a highly advanced RC aircraft. Depending upon motors, propellers and ready to fly (RTF) weight it can be consuming several hundreds or thousands of Watts, and can weigh up to several kilograms. Turning propellers or crashing RC aircraft can cause seriously injury to you or bystanders. Electrical short circuits can cause serious injury or fire. You do not want to inflict injury or property damage.

Never charge lithium polymer batteries unattended and never exceed rated charging amperage. These batteries can overheat and cause fire if improperly handled. If a battery has been damaged in a crash it is best to properly dispose of it and not risk a possible spontaneous combustion due to internal shorts hours or weeks later.

Don't fly too close to people or inappropriately close to or over property or near roads where you might distract traffic and cause accidents.

Know the limits of your flying skills and do not push the envelope. Always carefully observe your surroundings before taking off and note any hazards which you have to avoid (e.g. power lines, GSM masts, a partially obscured path over which people might suddenly enter your flying area).

If there are multiple people flying, stand in a group and keep all flying aircraft in front of you, keep bystanders behind you and preferably behind a fence or other barrier. If people suddenly enter the flying area and do not immediately respond to your friendly request to keep clear of the area, it is best to identify a safe landing spot and land immediately. Flying and fierce discussions do not mix. Do not allow yourself to be distracted from observing your aircraft and the flying area while flying.

Never fly within air traffic controlled airspace near airports (unless this is explicitly approved by and in communication with air traffic control).

It is recommended to fly at designated RC flying clubs airfields. When flying "in the wild" make sure you keep an appropriate distance from such fields to not cause interference. If you fly "in the wild" with FM radio control systems, you should preferably be able to check that nobody else is using the same channel (use a so called channel checker). If you use a 2.4GHz radio control system you will have less chance of interference when flying "in the wild". In some countries, RC flights are restricted to designated areas. Check with your local controlling agency first.

Always fly in such a way that you can see your aircraft. Flying behind trees (foliage) or other obstacles may degrade the RC signal and thus reduce control.

Do not fly too far away as you can very quickly become disoriented as to the models attitude air which could result in a crash.

Never point the tip of the antenna of your transmitter directly at the model. Signal strength is strongest on the side of the antenna, and reception is best when the signal comes from the side of the receiving antenna. Control distance may be reduced to less than 50 meters if both antennas are pointing straight at each other, while under optimal conditions (antenna's parallel to each other) it may be more than 1000 meters.

Avoid positioning your body between your transmitter and your model as water (body) absorbs part of the signal which may cause reduced control.

Do not fly in weather conditions exceeding your own or your aircrafts’ capabilities. As a beginner, do not fly outdoors if wind speeds exceed 25 km/h, preferably even less for first flights. With more experience and with a sufficiently powerful MK model, flights in surprisingly high wind speeds are possible, but don't be impatient. Gain that experience first.

Well, I could go on and on, but you get the picture: SAFETY FIRST!

Of course things can go wrong despite all precautions. Make sure your liability insurance covers personal and property damage caused by RC aircraft. If it does not, take a separate insurance. Relative to the cost of a MK the insurance is not expensive. And you know you will never need it if you have it, but that you will certainly pay dearly at some point if you don't have insurance.

Setting up

Flying is only possible with a correctly working model. So before starting any flight school lessons, you have to make sure your model is in a good condition mechanically. Make it a habit to check that all nuts and bolts are sufficiently fastened before any flight. If you haven't used "lock-tight" they may vibrate loose over time. Pieces falling off in flight are guaranteed trouble.

Although the MK is not very sensitive to CG shifts in both height and width, it is easier to fly the model with the CG a bit below center vertically and well cantered horizontally. The battery position in particular can help to correctly balance the model horizontally. One way to check that the CG is not too far off center is to lift the model up a bit at the tips of each of two motor arms. If it balances nicely in both nick and roll axis it should fly easily.

Make sure the propellers are properly balanced before mounting them and that they are mounted firmly and correctly (front and rear turn right, left and right turn left when seen from behind and above) and the motors turn in the correct direction. If a motor turns in the wrong direction, switch two of the three motor wires.

For initial flights it is best to start with easy settings without complex additional functions such as Altitude sensor, compass or GPS (e.g. default setting 3 ("Beginner / Camera"). Make sure all sensors provide correct responses to MK movements through the MKTool. Also test that all ESCs operate correctly and the motors turn in the right direction. When testing the motors either with the MKTool or with your transmitter indoors, your intent is not to lift off. So make sure the model is firmly fastened or held in such a way that the propellers cannot cause any damage or the model cannot unexpectedly take off.

Set up your transmitter correctly. If you have limited RC experience, or "clumsy fingers" set up "25-35% expo" on rudder (yaw), elevator (nick) and aileron (roll) so that the sensitivity of the stick around the central point is decreased. More than 35% will probably cause the control input - model response to feel very sluggish and may contribute to disorientation when trying to correct the model when it's getting away from you. Depending upon our transmitter, the expo value may have to be negative (Futaba) or positive (JR, Spektrum) to decrease the sensitivity. It may help to observe the effect of expo settings on a servo to make sure you have set it up correctly.

Make sure your batteries are fully charged, both for the MK and the transmitter. Make sure your batteries are of the correct amperage and C-rating to allow the MK to fly for at least 5 minutes on a full charge and do not drop the voltage too quickly at full throttle. 20C or better lithium polymer batteries are generally required.

Perform the first training flights very carefully in a quiet environment where there is little risk of personal or property damage (e.g. open field, large hall; no people walking around who are not involved in the activity).

Pre-flight checks

Always perform the following pre-flight checks before any flight:

• All mechanical links: correct and tight
• All electrical connections: correct and tight
• Propellers: properly fastened and undamaged
• Motors: properly mounted and turn freely (some "magnet stepping" is normal but the axles should be straight and on a push the props should turn a few cycles without visible oscillations or vibrations).
• Landing gear: properly fixed and undamaged
• Battery and other "loose" parts (e.g. camera mount, camera): properly mounted and fastened.

Starting up

Turn on the transmitter and select the correct model memory. Make it a habit to turn on your transmitter BEFORE powering up the model, and turning it off AFTER disconnecting the power from the model. Make sure your throttle stick is fully down (off) and all switches are set correctly.

Set up the MK on a reasonably flat, horizontal surface. Outdoors grass is nice. In case of mud or dirt consider a "heli-pad" made from sufficiently large pieces of plywood or canvas type of materials, if necessary weighed down or pinned down with some large nails. If flying outdoor, set the model up so that the front end is pointing into the wind, and that you will be standing downwind behind it. If flying indoors set it up so that the model is pointing into the hall and you will be standing behind it with any possibly bystanders and the entrance into the hall behind you.

Connect the battery and turn on the flight controller. Keep your hands free of the propeller arcs during these actions. Although it is highly unlikely that the motors suddenly switch on, the rule should be "Safety First" when handling or flying with the MK. If the beeps from the motors/ESCs, any indicator lights on the receiver and indicator lights and beeps from the flight controller all indicate the status of the model and the RC link are OK, step back 2-3 meters behind the MK. Your first flight will be "nose-out / tail-in" as this way you don't have to consider "control-reversal" (if you fly "tail-in" right = right, left = left, etc.; if you fly "nose in" from your perspective right=left, left=right, etc.).

If necessary, calibrate the MK (left stick in upper left corner until you hear the beeps).

First flights

You can move the left and right sticks with

• your thumbs with part of your hand gripping around the side of the transmitter, or
• your thumb and index finger either with the transmitter in a tray, or pushed a bit down with the sides of your hands with the transmitter on with a neckstrap.

Stick movements with thumb and index finger holding the tip of the stick tend to be a bit more accurate than those with the thumb pressed on the end of the stick. However, with a bit of experience both techniques work well. Using a neck strap or tray does have the advantage that the transmitter cannot suddenly fall if for whatever reason you let go of it.

All control inputs should be very small. Always avoid sudden large stick movements! The RC control is proportional meaning that small stick movements result in small MK movements, large stick movements in sudden and abrupt MK movements.

Use your timer. For normal flying it is not very critical, but for aerial photography flying it is very important and even for aerobatic flying it can make a difference between a successful flight and a underpowered crash. Most transmitters have a timer that can be set up as a stopwatch or as a countdown timer. For the latter you need to set the duration to correspond with the flight time you would expect from a particular battery pack. Make it a habit to start your timer at the time you start your motors. As soon as the motors are on, even at idle, power consumption increases. Only turn the timer off if the motors are also off. Note the time you have had the motors on/flown when you turn them off.

Now start the motors (left stick in lower right corner). All four motors should turn at low RPMs. Gradually increase the throttle until the MK just starts getting light on its feet. If this is your first flight, do NOT lift off yet! You first have to test control responses. At this point it should NOT show any tendency to yaw, roll or nick. If it does, there may be a problem that needs to be corrected first.

Push the rudder stick a little bit to the right (be carefully, do NOT move the throttle up/down while doing this). The nose of the MK should turn to the right. Move the stick back to central point. The MK should not turn further. Move the stick a little to the left. The nose should turn to the left. Turn the nose back so that it points away from you.

CAREFULLY push the elevator / nick stick up and see whether the nose of the MK wants to go down, tail up, and the MK wants to start moving away from you. Do NOT do this too aggressively. You do not want the MK to tip over and damage the propellers or motors. Repeat by moving the stick a little back. It should want to nick back and move back. Now with the elevator / nick stick back in central position.

CAREFULLY move the aileron / roll stick to the right. The MK should want to roll a little to the right and show a movement to the right. With the aileron / roll stick a little to the left of central it should want to move to the left. If all these tests went OK, lower the throttle and turn off the motors (throttle stick in lower left corner until the motors switch off).

Although you probably haven't left the ground, and it may not feel like it, you have in a sense just done your first flight and shouldn't have suffered any damage.

Lift off and landing practice

Double check that the conditions for flying are still safe (no people entered the flying area without you noticing as you were focused on the model, nose of model is pointing away from you and into the wind, nothing hanging loose from the model): Safety First!

If the flying conditions are still OK, switch the motor on again (throttle stick in lower right corner until the motors start up to idle). Increase the throttle stick until the model gets light on its feet.

Time for lift-off! Increase the throttle stick a little bit faster so that the MK quickly lifts off. You want it to go to an altitude of 30cm or more to get out of ground turbulence caused by the downward airflow from the propellers. Once you are at 30-50cm, gradually reduce the throttle to slow down the ascent, and gradually decrease it further to descend slowly land again. Do NOT suddenly decrease the throttle or you will crash. If you start descending too quickly, increase the throttle a little bit to slow down the descent.

First landings will probably be "bouncy", so try to stay between 30 and 50cm height on these first lift-offs. Once you are almost on the ground (centimeters off the ground or just at the moment before touching the ground), decrease the throttle a bit faster to avoid the MK responding too much to ground turbulence and acceleration sensor inputs resulting in repeatedly bouncing. Once on the ground pull the throttle stick back to idle.

If the MK drifts a bit during this phase, just reposition it on the ground between take-offs. We're not yet going to try flying it back to its position. Practice lift-off and landing repeatedly until you can fully control it and landings are soft and smooth. Reduce the throttle to idle between landings and recheck the environment!

If for some reason something goes wrong and the MK lands on its side or upside down, IMMEDIATELY turn off the motors (throttle stick in bottom left corner until the motors stop) to avoid unnecessary damage to ESCs, propellers or motors). Reposition it, and check for damage. Reposition yourself and recheck the environment. Restart the motors (throttle stick in bottom right corner until motors start) and restart lift-off and landing practice.

Repeat take-offs and landings until you are confident that you can land your MK smoothly without bumping or bouncing around.

Controlling roll, nick, and yaw

Once lift-offs and landings are very well controlled, try to lift-off and keep the MK at a given altitude by controlling the throttle so that the MK remains at an altitude between 100 and 200 cm. Do not go much higher or lower yet. You will probably have to constantly adjust the throttle a little to maintain altitude, especially if there is some wind. And there may be a little bit of drift. Don't try to correct it too much yet. If necessary land and reposition the MK on the ground.

You are now going to learn to control forward/backward or sideways motion at the same altitude.

Remaining close to your target altitude and very carefully move the aileron / roll stick left or right to move the MK a little to the left or right. Do the opposite to move it back. Try not to move the elevator / nick stick at the same time to avoid flying the MK towards or away from you.

Then do the same with the elevator / nick stick to fly the MK a little forward or backward. Do keep it at a safe distance from you (at least 2 meters). It is recommended to fly it away from you first (elevator / nick stick a little bit up) to a distance of about 5 meters, then stick down and move it back towards you ans stop it at a distance of 2-3 meters.

Once you can control the MK left/right and forward/backward, do some practice on rudder / yaw. From a hover position, carefully move the rudder stick to turn the nose of the MK approx 45 degrees to the left or right, and then yaw back. You do not yet want to go further than 60-70 degrees because you will quickly run into control reversal and get disoriented.

Remember: Small stick movements!

If you can't get the MK back to its starting position, it is safer for both the MK and yourself to land, manually reposition it and restart, rather than to continue to try and correct drift which could lead to disorientation followed by crashing the model into the ground or yourself.

Hovering

Moving left or right, or forward or aft is of course great. But the big advantage of a MK is that it can hover. It can hang still above a given point. Hovering an MK means that in addition to the self-stabilization by the flight controller you provide some additional control inputs to keep the MK over the same spot on the ground at the same altitude. Carefully combing the roll, nick, yaw and throttle inputs to correct drift in any of these four axis, trying to keep the model in a stable hover at between 1 and 2 meters above its take-off position. If the craft moves too far out of the hover area, just land and reposition it.

Hovering is a very critical flying skill so practice it extensively. It may require several hours of practice under different conditions to master it to such a degree that even in some wind you can keep the model within 20cm of its intended hovering position. If you can do this well, you will most likely be able to get out of trouble during other maneuvers by going into a hover quickly, reassessing the situation, and flying to a safer position or landing spot.

At first, just practice over the general area of your starting point. Later consider marking a point on the ground (e.g. a helipad made from plywood or canvas, or a pylon or plastic bottle) and hover exactly above that point. You may be surprised at how lenient we are for ourselves if there is no marked hovering position, how difficult it can be to stay correctly above a clearly marked spot for several minutes.

Flying manoeuvres

Once you are capable of a prolonged stable hover you can progress to practicing basic flying maneuvers. The flying maneuvers can be subdivided in standard flying and acrobatic maneuvers. A particularly important flying maneuver is "nose-in" flying.

For each of the basic flying maneuvers consider forcing yourself to fly accurately by marking the positions on the ground above which you must transit from movement to hover and/or landing.

House pattern

A typical flying maneuver is the "house". Lift-off, at about breast height hover for about 5 seconds, then fly 3-4 meters sideways, again hover for about 5 seconds and land. Then do the same in opposite direction. Keep the nose pointing away from you (tail-in).

Square pattern

Mark four corners of a 3 to 5 meter square around your lift-off position. Lift-off, hover for 5 seconds, and then fly the shortest line to the first corner. Hover above this corner for 5 seconds and then fly to the next corner in a direct line, hover for 5 seconds, etc. Do this in both directions (clockwise and counter-clockwise). You may have a clear preference but should be able to do this in both directions. Also occasionally fly across diagonally from one corner to the opposite. Make sure you do this purposefully: have a flight plan and don't adapt going from one corner to the diagonal corner instead of the next because you drifted off a bit and it looks so sloppy if you have to fly a curve instead of a straight line. During movement from one corner to another keep the nose directed away from you. Fly at a constant altitude (between 1 and 2 meters). Try flying at a constant speed. Keep the speed low to allow easy transition to hover without overshooting the mark.

Flying nose sideways

Once you have mastered flying house and square patterns "tail in", it is time to start gradually getting used to flying the MK more from the models' perspective. So repeat the above house pattern, but now when preparing to move sideways, in the hover yaw (turn) the nose a bit (30-60 degrees) in the direction you will be flying in, and then try flying the same straight line that you could fly so nicely "tail in". Repeat this until you can comfortable turn the nose the full 90 degrees in the direction you want to fly in and not confuse the roll and nick directions.

Once you can fly the house pattern nose sideways, you can also practice the square. However when moving back towards you, either yaw the model so that it is again nose-out, or fly it sideways (alternate this according to your "flight plan").

Tip: Flying nose sideways can be easier if you also turn your body sideways a bit. In fact you will then be flying tail-in again but with the model to your left or right. This trick does not help much in the transition to nose-in flying. But keep in mind if you get into trouble during flights later on due to some disorientation. It may help you recover.

Other fun patterns

Two patterns are a not very obvious but quite fun to practice:

• The walk-along, and
• The circle me.

The walk-along

For the walk-along you walk along a path with the MK tagging along at a fixed position in front, or next to you. If you reach a corner, of course you must yaw the MK to be tail-in or nose-in or sideways again, whichever mode of flying you want to practice. Of course you do have to make sure there are no other people walking the path. Practical use of this exercise is mainly in the RCAP arena where you often do walk around a bit to change your position and that of the model to take pictures from a different angle. Also the change in relative positions between you and the model forces you to focus on the model and not orientate your control movements to the position of the model relative to its surroundings.

The circle me

For the circle me, the intent is to fly a full circle around yourself, or another given target, at a fixed distance and yawing at a same angular rate as the craft is moving through the circle. So if you fly it tail-in, the craft should be looking straight out from the circle (and if shooting video this would result in a wide panorama). If flying nose-in it should be looking you in the eye at all times. Try to also maintain a constant altitude during this exercise. And make sure that there are no people standing anywhere near you if you do this at practice hover altitudes (1-2 meters). This is again an exercise which is useful later on for RCAP flying. However it also helps improve control of left and right sticks.

Flying nose-in

The most difficult way of flying is with the models nose pointed at you. Once you have mastered flying nose sideways, you're halfway there.

There are now two ways to progress.

1.You can restart hovering practice but now lifting off with the models' nose pointed at you. The advantage of this approach is that you learn to transition well from nose in to hover to flight and vice versa, a critical ability to get out of trouble. If you start with hovering nose-in just repeat the house and square patterns after that.

2. Alternatively you can gradually progress from nose-sideways flying the house and square figures to flying them with nose in the direction of flight at all times, and eventually to fully nose in (i.e. flying away from you with the noise pointing at you, and flying from left to right or right to left with the nose pointing at you). Before you do this, practice 360 degree yaw in both directions from normal tail-in hover.

In all cases make sure you practice flying the square nose-in in both directions (clockwise and counter-clockwise).

Practice nose in flying very, very extensively. You must eventually be able to transition from tail-in to nose-sideways to nose-in flying without any hesitations or mistakes with respect to control inputs for flying your intended pattern / direction, and transition at a moment’s notice to a hover.

If you have trouble controlling the aircraft nose-in at some point, just yaw it back tail-in and regain hover position. Never panic and pull the throttle down !!! If necessary, slightly increase the throttle to remain between 1 and 2 meters above the ground until you have been able to regain hover. If all else fails, very carefully decrease the throttle and land.

Tip: Move the roll stick towards the "hanging" wing or rotor to stabilize an aircraft which is flying towards you (nose-in).

Tip: Until you have mastered nose-in flying very well do NOT attempt either aerial photography or aerobatic flying. Not having mastered this skill properly will eventually cost you your camera or model.

Aerial photography and video flying

Flying for aerial photography poses several unusual challenges. Compared to normal or aerobatic RC flying you are usually much more restricted in the space you have to take off and land from, you fly closer to people, property, and all sorts of obstacles, and you fly (much) higher than you do for normal or aerobatic RC flying. In addition you if you fly alone you will also have to control the camera. And for video flying you want your flight to be fluent so that the resultant movie requires limited editing.

The last thing you, the bystanders, or your fellow RC AP (radio controlled aerial photography) and RC AV (aerial video) flyers are waiting for is accidents or complaints. Therefore do NOT do any aerial photography or aerial video flying until you are confident that you can properly control the MK under the conditions you will need to fly in.

Note: virtual reality VR flying (flying with a video downlink, controlling the model as if you are in the pilots' seat) is beyond the scope of this training. However, going through the training below before attempting VR flying is probably a very good idea. Before moving on to RCAP/RCAV flying training, a bit of a reminder:

SAFETY FIRST!

As RCAP/RCAV flyer, be compulsively obsessive about the following checks:

• All mechanical links: correct and tight
• All electrical connections: correct and tight
• Propellers: properly fastened and undamaged
• Motors: properly mounted and turn freely (some "magnet stepping" is normal but the axles should be straight and on a push the props should turn a few cycles without visible oscillations or vibrations).
• Landing gear: properly fixed and damage free
• Battery and other "loose" parts (e.g. camera mount, camera): properly mounted and fastened
• Check the sensor values regularly between flights, in particular after hard landings or crashes
• Check out the location where you will fly thoroughly before you fly and note hazards in the vicinity:
  • Make sure you know what is behind a rows of trees ! Look up the location beforehand on Google Earth or similar (may also help find locations of interest in the vicinity which may make a long drive more worthwhile)
  • Make sure you maintain a sufficient distance from airfields and will not be flying in the usual flight paths of e.g. emergency helicopters
• Determine beforehand which areas around the target contain dangerous or crash sensitive zones (e.g. transformer stations, petrol stations, chemical installations, glass-houses, masses of people, etc).
• Plan more than one emergency landing zone beforehand and in any case have a good idea of your necessary flight path to an emergency landing zone at all times.
• Check if the RC controls of the MK all function properly before taking off.
• Check if the camera battery is fully charged and if the camera is set up correctly before mounting it.
• Check the shutter control and tilt control before taking off.
• Make sure you fly with properly charged batteries in the transmitter and the MK. You need to know the MK battery endurance before you engage in RCAP/RCAV flights.
• ALWAYS START YOUR TIMER AT MOTOR ON so that you know how long you have been "in the air". Land well before you can expect the low battery alarm to kick in.
• If the alarm kicks in early with a particular battery, recharge it with a balancer and check it out flying over an open area to see whether it is back to normal. If the battery is clearly degrading, replace it. That is cheaper than a low-power crash with your camera going to bits and a nice dent in something on the ground.
• IF IN ANY DOUBT ABOUT THE SAFETY OF THE FLYING CONDITIONS, OR YOUR ABILITIES UNDER THOSE CONDITIONS, DO NOT FLY. It is better to disappoint a possible client than to cause an accident. All clients well appreciate your focus on safety and thus may well come back with other orders despite such a disappointment.

For RCAP / RCAV flying with MKs, use of the compass and air-pressure sensors are strongly advised. At this point in time 3-axis magnetometers and GPS support are of some benefit but not absolutely required.

Extend the basic flying practice with the following maneuvers in an open field:

• Practice flying up to 5-10 meters, and then hover. Practice yawing 360 degrees in steps of about 15 degrees. Press the shutter control between each step of the yaw. After doing a full turn practice tilting the camera mount down about 15 degrees and doing another stepwise 360-degree yaw. Do this in both directions while maintaining a stable hover.
• Once you are confident that you can control the MK at this altitude, go up to about 20 meters and repeat the exercise. Note that from about 20 meters and up the altitude hold function can be used quite well to help stabilize the altitude. However you will still have to control nick, roll and yaw. Do not fly any significant distances horizontally until your are confident in hovering at larger altitudes. Only increase your altitude in a stepwise fashion after you are confident at a current altitude.
• The maximum altitude you can fly under visual control is the altitude at which you can still sufficiently see the position of the MK to allow you to properly control the hover. This will vary based on size of the MK, eyesight of the pilot, and experience. For most people it will probably be between 50 and 75 meters. That may not seem like much, but remember that a 20-storey building is usually about 60 meters so you can still take good AP pictures of even such a high building from an MK. You can carefully test this envelope in an open field away from people and houses. Never try to extend this envelope beyond your known capabilities while doing an actual RC AP flight.
• Once you can confidently hover at altitude, practice flying a virtual square of about 50 meters in each direction at the same altitudes, starting at about 10 meters and then working your way up. This is an important maneuver to master as you usually want to take your pictures from different angles.
• For aerial video flying after having mastered the above exercises draw up a clear flight plan in which you determine a flight path and direction of view of the MK at each point in its path. Start easy with a square or circle at about 10 meters with a gradual ascent (either vertical or along a slope) yawing the MK if needed to keep the nose (camera) pointed at the intended target(s). Gradually increase the complexity (e.g. with hover points where you do a particular yaw, tilting of the camera mount, increasing the altitude, etc). Also practice lower altitude flights along curving paths as for AV you may also be following e.g. speedboats or go-carts from altitudes of just 1-3 meters.
• Gradually allow yourself to fly in increasing wind conditions. Although you preferably want only light winds, a reasonably powerful MK for aerial photography, and its pilot, should be capable of handling wind speeds up to 45 km/h.

Once you have mastered the above, find a quiet park or field with some obstacles of different height (e.g. some spread out trees) to add complexity. Try to stay well clear of the trees. Remember that they are alive and always trying to grab your MK out of the sky. But think of the trees as houses, obstacles, and targets, and use them to gradually increase the complexity of you flying conditions.

Note down an outline of your flight plan before every flight, or describe it after a flight. It may well be that you want to make a very similar flight at another time at the same site to show changes over time. The closer you can copy your previous flight the better the results will be.

Once you can fly confidently in an area with a number of obstacles, you can probably start doing some "easy" first RCAP or RCAV flight. I.e. a lone house or row of houses surrounded by reasonably open fields is a good starting point.

Over time it is very likely that you will progress to flying in more densely populated areas. As indicated above, be obsessively compulsive about the quality and condition of your aircraft and RC system. Do not compromise on safety.

And then, as a friendly suggestion: If you enjoy the aerial photographs you take with these wonderful machines, consider helping the MK team to progress the development of these aircrafts further with contributions or donations.

Aerobatic flying

The MK is limited in its aerobatic capabilities to flying patterns, yaws, rolls and loopings. Knife-edge flying and flying upside down is not possible. Moving through the knife-edge and upside down phases of loopings and rolls is only possible with kinetic energy.

Before attempting aerobatics make sure you can control your MK at a distance and at greater altitudes. Go through the Aerial Photography flight training up to altitudes of about 30 meters and at distances of 50-75 meters without acrobatics.

Flying patterns or yaws at various speeds and altitudes is a matter of extending the envelopes of basic flight training and is not further discussed here.

The looping-function was only introduced in the MK Flight Controller Software version 0.61 and later. Use the latest version. You have to choose an acrobatic parameter set and turn the looping function ON in the MKTool. The looping function of the MK is completely software controlled. At certain points in the stick-movements, the flight phases are switched. It is important to move the stick completely to the switch points without waiting for optical feedback that the MK is responding to the stick movement! Do NOT change the stick position while in the maneuver to see the model's reaction. This can result in the model not being able to complete the figure e.g. remaining in an inverted position resulting in a “rapid descent”.

Example of an upward looping

• Fly the MK up to a safe height (> = 20m) and fly forward into the wind.

• By pulling the nick (elevator) stick completely back for about 1 second, the looping will be flown.
• Watch the model fly the maneuver carefully and only let go of the stick when the MK has almost completed the looping, reached a flight attitude about 20°-30° from the horizontal plane. The exact timing of letting go of the stick at that point will determine the preciseness of the end of the looping and transition back to stable flight. The exact point is determined by wind and MK characteristics (weight, power) and must be trained extensively. If the MK overshoots the horizontal flight attitude, correct this with a bit of push on the nick stick.

Other types of loopings

The downward looping, and the left and right rolls, which in effect are just sideways loopings, are performed in a similar way. Loopings can be flown without much forward speed. They are optically nicer if just before the looping a slight ascent is started.

Possible errors flying loopings or rolls

• Beginner setting still active resulting in delayed or reduced responses. You must at least have chosen normal, preferably acrobatic settings.
• Looping option not activated with the MKTool.
• Altitude too low.
• Stick movement too slow resulting in a slow start phase before software takes over and therefore too little kinetic energy to complete the looping.
• Too early or too late release of the control stick resulting in inverted or knife-edge attitude of the MK.

Loopings and rolls can be flown in Heading Hold mode as the angle of tilt and roll follow stick movements proportionally. However the looping function is NOT activated if Heading Hold is activated. So if flying loopings in heading hold mode you must fully control the looping.

Warning for flying acrobatics in windy conditions

When flying outdoors in very windy conditions always turn the looping function OFF !! Aggressive roll and tilt stick controls under very windy conditions could result in unintended activation of the looping function, which close to the ground will have predictable results.

Final words

As indicated above the MK is an advanced aircraft, which can pack significant power and can cause serious damage to itself, you, bystanders or property. Make sure you don't push the limits of your envelope too far too fast. That will save you a lot of frustration and money. You and probably many bystanders will have a lot of fun with the MK if you gradually progress your capabilities and if you do not compromise the golden rule:

SAFETY FIRST!

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