RC Helicopter

Blade Tracking and Balancing for Remote Control Helicopters

2011-10-04T02:27:00.003+08:00

Introduction

WARNING: Tracking adjustment is a dangerous procedure. Keep at least 5m from the spinning rotorhead. It is also recommended to wear eye protection.

Before following this section, if you are working on a new build, or have yet to mechanically set up the rotor head, please read this first: CCPM Mechanical Setup. It will make sure that you have a good setup on your machine before attempting to balance and track your blades. By the way, my blog will list the latest radio control helicopter guides and tutorials. Sometimes you will get lucky, and have perfectly balanced blades out of the packet. The same goes for tracking, you may not need to track your blades at all. Either way you should definitely follow this procedure to make sure they are operating correctly.

Blade Balancing

This is the easy bit. Essentially, when the rotor blades are manufactured, there might be very slight imperfections in the weight of each blade. Not noticeable to you or I, but once spinning at 1,800 rpm or more, this will cause vibrations in the helicopter. The greater the weight difference, the greater the vibrations.

Helicopter Blade Balancer

A blade balancer comes in useful at this point, you will need to bolt your blades on to it and see if they "balance". If they don't, its time to use the pretty stickers that came with the blades. On the lighter blade, place the metallic sticker at a point along the blade where it makes them balance about there pivot point. Just lay it on initially without removing the adhesive back. When you are sure of the position, fix it in place. You should now have a set of balanced blades. On to the tracking.

Blade Tracking

The first thing you need to do is see if they are actually out of track or not. Time to get out some blade tracking tape, or electrical insulating tape will do. Make sure any edges of the piece of tape are towards the trailing edge of the blade. That way the tape wont come off due to air getting under it. Ideally a different color tape on each blade. Again, if not, just make sure one is well marked.
You will now need to spool the RC helicopter up to a decent head speed, around that suitable for a hover. I personally strap the heli to a workbench, but you can also bring the helicopter into a hover around head height and check from there. What you are looking for is wether one blade bends more than the other. This will be evident as an obvious doubling of the imaged rotor blade edge. With one blade higher than the other. If this is the case you need to adjust some linkages, as your blades are not tracked.

The Reasons Behind Out of Track Blades

Why does this happen i hear you say?! Well, simply, like the balancing, there are very slight imperfections in some blades. So, when a large external force is applied to them they can behave differently. In this case it is one blade flexing more than the other. this is not the only cause, in fact, the more usual suspect, is that when you tried to get zero pitch in your blades during the CCPM setup. There may be some slight pitch in the blade that is impossible to get out during setup.

So, as you may well have guessed, if there is more pitch on one blade than the other, the it will generate more lift, causing it to flex more than the other, and fly higher than its counterpart. Luckily this is very easy to fix.

Effects on Helicopter Headspeed

One thing to think about is headspeed, if you want to get all technical. Say the blades are out by a random figure, lets say 10mm. You could adjust the links so the one flying low comes up to meet the top one, or you could do it the other way round. We have to consider how this will effect the headspeed. As we are changing the pitch of the blade. The safest bet is to raise, and lower each blade respectively by the same amount, so the tracking meets in the middle for the helicopter.

To sum up these effects: If you are happy for the headspeed to increase, the higher blade needs to be lowered. The same is true if you want a lower headspeed, raise the lower blade. As i said above, making them both meet by adjusting equally, will maintain your current hover headspeed.
To actually adjust your blades, you will need to change the lengths of the linkage rods that control the pitch to your blades. It is wise during this step to refer to the manual that came with your RC helicopter, as they can be different from heli to heli. I will provide below a quick guide on how to adjust these on a T-Rex 500 helicopter.

The Align T-Rex 500 Method

Helicopters sharing a traditional flybared rotor head will usually share the same linkages from the swashplate upwards. So the instructions for the T-Rex range will be similar, if not identical to that of other manufacturers. But again, always check in your particular helicopters manual, for vendor specific instructions.

WARNING: Tracking adjustment is a dangerous procedure. Keep at least 5m from the spinning rotorhead. It is also recommended to wear eye protection.

So, after following the previous instructions with the heli running and inspecting the blades. Look at the path of the blades carefully. If they are rotating on the same path, no further action is required. If one is higher than the other, then apply tracking corrections immediately.
In the image to the right links C and D, connecting the top seasaw arms to the blade grips are used to adjust for regular/medium amounts of trim to blade tracking offset. E and F are to be adjusted if you need to trim out small amounts of deflection on the tracking.

The blade with the higher path has to much pitch. Lengthen links C or D, depending on which blade is out of track. As above, if it s slightly off track, shorten linkage rods E or F. Remembering if you want to keep the same headspeed as before adjustments, to bring one blade slightly down, and the other slightly up to meet in the middle.

If you have followed the CCPM setup, and this tracking guide, you should now have a good mechanical set up on your RC helicopter. Happy flying!

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Throttle and Pitch Curve Setup

2011-10-02T23:34:00.000+08:00

RC Helicopter Pitch and Throttle Curves a Simple Guide

Introduction to Throttle and Pitch Curve Setup

Pitch and Throttle curves. People get to easily confused by this subject. It is mostly because they look for other peoples settings to use as there own, and don't truly understand the mechanics behind them. So when they don't work, they are unsure of what to adjust to rectify the problem, for instance if you are suffering from a low headspeed and "wagging" RC helicopter.
This subject is in fact very easy, and it just requires a little careful planning to get the perfect pitch and throttle curves for your RC helicopter. I will also briefly look at idle up pitch and throttle curves for the budding 3D pilot. My blog will list the latest RC helicopter guides and tutorials.

RC Helicopter Servo End Points

A little digression first, if you followed my previous guides, and in particular the mechanical setup guide. You will have seen we set the end points for the servo travel on the helicopter. It is useful to just spend a few minutes understanding how curves fit within those end points. When we have the servo travel set at 100%, we can increase or decrease that value, which then restricts or increases the servo travel. The pitch and throttle curves work within these pre-set end-points. So 100% at point 5 on a throttle curve corresponds to 100% servo movement if it is set to 100% as the end point, or 125% if set to this in the end point menu.

So remember, pitch and throttle curves work within your end points. When we initially set up the radio system, we gave the pitch a linear curve. Normally most radios use a 5 point pitch and throttle curve, but some more advanced radios use a much higher granularity allowing for a higher resolution curve. So in a linear curve we have the 5 points corresponding to the 5 stick positions in a linear fashion. P1=0%, P2=25%, P3=50%, P4=75% and P5=100%.
How this information is displayed will depend on your particular hand-set. Some will display it as a visual graph, and also as you move the throttle stick, will also update the relative position on the graphs axis. Others will just list them as text, so P1, P2 and so on.

Pitch Curves

After the mechanical setup, we arrived at a ±11° pitch range, with a linear curve this then means at P1 we have -11° pitch, and +11 degrees at P5, with a linear change between the two points. Crossing P3 at zero degrees pitch. It is possible to change these points to tailor how the pitch changes as we move the throttle stick. In normal mode we most certainly don't want -11° of pitch at zero throttle. But we do want this kind of pitch curve in idle up for 3D flying and upside down antics, but more on that later.

Getting back to end-points again briefly, we can use the throttle and pitch curves to set "fake" end points. So for instance if P1 is changed to 30% rather than 0%, then low stick now starts at a 30% value of the linear curve. So we will not get the full travel distance. This can be very useful. So with the pitch curve for normal mode flying you would make a higher starting point to make less pitch range between bottom and centre stick.
Changing P1 and P2 of the linear pitch curve, will allow us to reduce the negative pitch range of the helicopter. We are after a linear curve between P1 and P3, the same for the curve between P3 and P5, but at a different rate of increase. Ideally -3°, or -2° for P1, this means we wont slam the helicopter into the ground when trying to land, but also we need negative pitch to be able to bring the heli down in high winds.
The best way to set P1 and P2 is to use a pitch gauge. Attach it to the blade, and set P1 to when you read approx -3°/-2° of negative pitch. P3 will still be at zero degrees pitch, so set P2 halfway between the two. This is now your normal pitch curve Leave P3,P4 and P5 the same to match the idle up settings for these points. As the idle up switch is flipped whilst in the hover, so they need to match, usually at around 5°/6°. This normally corresponds to around ¾ stick for the hover.

Throttle Position	Example Normal Pitch Values
P1	40
P2	45
P3	50
P4	75
P5	100

Throttle Curves

In a RC helicopter, the motor doesn't always provide power in a linear fashion, especially electrics, the power band is normally quite high. If it was linear curve, it would match the pitch change exactly, which wouldn't work. If the rpm is low on the headspeed for the given pitch, we need a higher motor rpm to increase the head speed. As our pitch values are now set. (curve rising steeply then plateau). A symptom of low head speed is oscillating in the hover, we now adjust the throttle curve to give the correct headspeed at the appropriate stick position.
The idea now is to match the power band to the correct pitch, so at 11°, we need the maximum motor rpm, again we are in normal mode, so we need a curve with a high power band. Rising fast, and then levelling out, to provide the maximum power as loads are applied to the blades, and drag becomes a factor.
Ill give a "text book " example here, what we are looking for is for the throttle to ramp up sharply then flatten out. So this would be P1=0%, P2=50%, P3=80%, P4=90% and P5=100%. Remember as the throttle stick moves we are going through two curves, pitch and throttle. Both have an effect on lift, but our pitch values are fixed, so the throttle values are the ones that need "tweaking" in order to maintain the correct headspeed of the helicopter.

Throttle Position	Example Normal Throttle Values
P1	0
P2	50
P3	80
P4	90
P5	100

Idle Up Throttle and Pitch Curves

So, now for the scary bit (although, it really isn't that scary!) idle up! So, eventually you will want to fly upside down. If you try that in normal mode you will have an expensive repair bill, and dented pride. So we need to adjust our pitch and throttle curves to take this into account, remember, we set the helicopter up mechanically to be able to fly upside down, but we did not allow for this in our normal flight mode. Luckily, modern computer radios allow you to have a second, and even sometimes a third set of curves, that you can swap to at the flick of a switch.

Idle Up: Pitch Curve

So what we are looking for is the same amount of pitch but negative in the bottom half of the throttles travel as we have in the upper half for positive pitch, so lets say ±11°. This is simply our original mechanical linear pitch curve, this will allow for an equal amount of positive and negative pitch at the extremes of the stick movement. Set the idle up pitch curve to these numbers.

Throttle Position	Example Idle Up Pitch Values
P1	0
P2	25
P3	50
P4	75
P5	100

Idle Up: Throttle Curves

So as I said, we
need/want to fly upside down, and as pulling back on the throttle is now negative pitch, a linear curve on throttle would give zero throttle. We most definitely don't want this to be happening, in fact we want an increase in the motor to pull out from our manoeuvres as we press on through increasing negative pitch values.
This equates to a throttle curve looking like a "V" as we need the correct power from the engine at the appropriate pitch value. At mid stick, P3, we do not want 100% throttle, as there will be no load on the blades at zero degrees pitch, so we reduce the throttle here to stop the headspeed increasing like a banshee, we apply a linear increase either side of this, with P2 and P4 to match a linear curve. Similar to the normal mode, these values may need "tweaking" in order to get the correct head speed. We could also use a "U" shape, but the same theory applies and for this example we will concentrate on the linear increase either side of centre stick.
With these settings we will get an increase in rpm when the idle up switch is engaged, this is normal, and also the way it is normally kept. If this is unnerving, the throttle curves can be adjusted so at the ¾ stick position of the hover, when we engage idle up, they match to stop the slight and sudden jump in the helicopter.

Throttle Position	Example Idle Up Pitch Values
P1	100
P2	95
P3	90
P4	95
P5	100

Conclusion

So if you have followed the mechanical setup, radio setup, blade balancing, and blade tracking guides this should be the final step in the setup of the helicopters rotor head. The above examples are suitable for a wide range of RC helicopters, some may differ slightly, if in doubt, always refer to the manual, or a reputable on-line forum. You will find the members of this community more than willing to help you. Thanks for reading.

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CCPM Mechanical Setup

2011-10-02T23:03:00.002+08:00

CCPM Mechanical Setup

A good mechanical setup on the rotor head of a remote control helicopter, can be the difference between a model that almost flies itself, or one that is destined to hit the ground at high speed. OK, so they might be two extremes, but time invested now will be paid back ten fold. By the way, my blog will list the latest radio control helicopter guides and tutorials.

Radio Settings

First things first, start fresh on your transmitter, and select a brand new model channel, or if for some reason you don't have the luxury of multiple model memories, reset to factory defaults. This forces all trims to be reset, including the on stick ones, and sub-trims.

Go into your swash mix menu, and set the pitch, elevator and aileron to 50% swash mix. Set your swash type to 120 degree CCPM in the swash menu of the radio set (Yes, this "How to" is written for a 120 degree swash, from the swash up however, there are many similarities, so it will still be useful if you have a 90 degree swash). Lastly, make sure all other mix's are off, such as revo mix. Set all end points to 100% on the servo travel/end point menu.
Whilst setting up the helicopter head, we want linear throttle and pitch curves, so set these up now if this is not so. That is for the 5 stick points, 0%, 25%, 50%, 75% and 100% the throttle and pitch curves should match the stick values, going up linearly from 0% to 100%.

Receiver and Servo Connections

Now, lets get everything connected. You may have all ready done this, but ill just skim over the essentials. I find it easier to use a standard receiver pack to power the servos and receiver whilst setting up. This saves having to incorporate the ESC and a LiPo. If you do choose the later option, ensure your motor wires are disconnected whilst working on the remote control helicopter. A good habit to get into, and essential for safety is to turn the transmitter on first, and then the receiver.
The servo towards the back of the swashplate is connected to the elevator channel on the receiver. The two forward servos can be connected to either the pitch or aileron channels on the receiver. Later mixing in the radio will sort out there orientations.

Servo Movement Directions

Now we need to get the servos and the swash moving in the rite direction. A modern RC helicopter CCPM swash is quite a complicated and confusing thing. But take some time and work carefully, and it most certainly isn't rocket science. The two tools we will be using are "servo reverse" and "swash mixing". The thing to remember is servo reversing works on only the servo in question. If you want to reverse multiple servo movements at the same time, you will need swash mixing.

The first thing to check is what happens when you move the control stick forwards on the cyclic. The swash plate should tilt forward. This means the elevator servo horn should rise. If it falls, and the helicopter swashplate tilts backwards, go into the reverse menu, and reverse the elevator channel. We want to do the same now for the left and right movement of the cyclic stick. It should tilt the swashplate left and right. As an example if we give full left cyclic on the remote control helicopter, the left hand servo horn should dip, and the right one rise, thereby tilting the swash to the left. If not, reverse the appropriate channels in the servo reversing menu.
Next, we want to see what happens when we increase the pitch, the whole swash should remain level (roughly, more on that later) and rise uniformly. If not, you will need to go into the swash mix menu, and reverse the value of the pitch entry, so if it is +50% change it to -50%. So to sum up, we need all 3 servo horns rising for up pitch, down for down pitch. Left cyclic should mean the left servo dropping and right rising, the opposite for right cyclic. Forwards elevator means the rear elevator servo will rise, and the forward pitch and aileron servos will fall.

To correct a single servo use servo reversing, if all three are not moving in the correct order it can be corrected with swash mixing. We are now ready to move onto servo arm alignment on our remote control helicopter.

Helicopter Servo Arm Alignment

Now it is essential to have followed the earlier instructions regarding correct initial radio setup. Make sure you have power to your servos, and the helicopter pitch/throttle is set to 50%, this needs to be as accurate as you can manage. You now need to get those servo horns on at 90 degrees. That is horizontal, or if you prefer, parallel to the ground. Now the grooves on these servo horns are not uniform, different horns, and different orientations will yield better results on your RC helicopters servos. Play around for a bit and get it as close as you possibly can.
Chances are you will have them nearly perfect, but not quite, that's OK, we can use sub-trims on the radio transmitter to correct for this. So head on in to the relevant section on your radio, and play around with the settings for each channel by a few notches until you can judge the arms to be at 90 degrees. A good tip is to line them up against the servo casing and use that to judge the alignment. Make sure to put the ball links on the inside of the servo horn, that is so the linkage will come between the servo horn and frame. Always remember to use loctite on these, as you don't want them coming loose during flight.

RC helicopter Swashplate leveling

Again, the pitch control should be at 50% for this step. I wont go into to much detail here, many people on many different remote control helicopters use different tools, tips, and techniques. Do whatever you feel is best. I do however recommend a swashplate levelling tool, they can be as cheap as a few pounds/dollars. The idea is, with the pitch at 50%, and all servo horns at 90 degrees, the swash should be perfectly level with the helicopter. If not use your tool, or judgment, and start adjusting the 3 push rods from the servos to the swash by a single turn, and re-measure. It is worth mentioning now always follow the manufactures instructions for the lengths of push rods as an initial starting point, some times they are spot on. Repeat this until the swash is completely level. You also now want to check that at 0% on the throttle/pitch stick on the transmitter the swash doesn't come down to far and hit the washout, also at bottom pitch, you should check the full range on the cyclic, as to make sure the swash doesn't hit the frame. If it does, raise the swash by turning all of the push rod linkages by the same amount, until these interactions are removed.
Now complete the construction of the rest of the head, as per the manufacturers instructions, up to but not including putting the blades on. Before moving on, you want a completely constructed head in order to set up precisely all the components. We will adjust out any irregularities.

Sea saw Mixer Arms

Some people think of this stage as being the hardest, but it is the simplest to be honest. Just take your time, and re-check your work. Essentially, all we are looking for is that the bottom and top sea saw mixer arms are nice and level when the swashplate is level and at 50% stick. To achieve this we need the flybar cage to be locked into position with an appropriate tool, an allen key as per Finless Bob, or judged bye. Arms needs to be straight and level with the bar of the flybar cage. This is achieved by adjusting the linkage rods going from the swashplate to the mixing arms at the top of the heli, lengthen or shorten to achieve the perfect balance.

Unlike the final push rods to the blade grip, these can be different lengths. It is an iterative procedure, where you adjust one set, see how it effects the sea saw arms, then re adjust. Each time getting smaller and smaller in adjustments until they are level. The top arms can be judged by lining them up with the flybar cage. The bottom ones by looking through the head to the arms on the other side, they should be parallel with each other and look at the alignment of the ball links on the mixer arms, repeat this on both sides.
The bottom sea saw arms can be adjusted uniformly by raising or lowering the swashplate linkage rods, applying the same amount of adjustments to them all at the same time, whilst the pitch is still at 50%.

Zero Pitch on Blade Grips

We would now like to achieve zero pitch in the blades at 50% throttle/pitch. This proceeds on the assumption your setup to this point is correct, including the aligned sea saw mixer arms. Put a set of blades on now. You will need to lock the flybar cage in position, check out Finless Bob's hack with an allen key to achieve this, or buy a tool, either way you need to have a steady and fixed flybar cage.

At this stage the blades should now have zero pitch, this can be measured with a pitch gauge, or judged by eye. If doing it by eye, and you have flat tops on the blade grips, you can line them up by eye, the flat edges of each blade grip being on the same plane as each other. You will need to take the button head of the top of the head. Another trick, is to take the blades of, and look at the bolt that goes through the blade grips that normally holds the blades on, this should be vertical.
If you have any pitch in the blades, adjust the very top most linkage rods to remove this, and re-measure. These rods should be identical in length, this is very important. So if one blade has more pitch than the other, something has gone wrong with your setup further down the head of the RC helicopter, so you will need to re-check this from the swash to the top mixing arms.

Checking Head Full Pitch Range

To do this put some blades onto the RC helicopter and measure the full pitch range over the full length of travel. Increase or decrease the pitch value on the swash mix. Taking note that the swash doesn't hit any of the other mechanics at the bottom or top of its travel. As we started with a swash mix of 50%, 70% should give roughly around 14 degrees of pitch. This will be a little to lively for a beginner. 60% swash gives about 11 degrees of pitch, which will be a good starting point for a RC helicopter pilot. As a reminder, when adjusting the full range travel on your helicopter, make sure the swash doesn't hit the washout or the frame during its travel. Similar to when we were adjusting our ranges in the sea saw mixer arm setup stage.

Flybar Paddles

I did notice when i was first starting out, that there wasn't much information on how the flybar paddles should be setup. Luckily, they are very simple. they should be of equal length from end to end on each side of the flybar cage. The leading edge pointing in the same direction as that of the blade (The paddles and blades should have there leading edger pointing in a clockwise direction by the way). Lastly they need to be flat and level, you can judge this by eye, line the paddle edge up with the top sea saw mixer arm, inside the flybar cage, they should be parallel to each other.

Checking for CCPM Interactions

It is best now to search for any CCPM interactions, this is due to not all servos moving the same amount, or linearly. This can be checked on the swash, but due to the mixing ratios, the paddles are much more sensitive to these interactions, so keep an eye on these while checking, you can use a small bubble level on one of them. Have the paddle perpendicular to the tail boom, and look for elevator interactions, do the same with it parallel to it to look for aileron interactions
.

If you spot any movements, go into end point adjustment section/travel adjustment section of your helicopters radio. So for instance if at full pitch the bubble moves backwards, apply an increase to the forward elevator end point in order to bring the bubble back to level, same goes for aileron interactions. You will still get in between CCPM interactions, but it is not overly important to fix these, getting full, bottom and centre the same is important, on digital servos we can get rid of this with P mixing but it is a task that is very time consuming.

The last step, reduce or increase pitch setting at max pitch in swash mix to get 11 degrees positive, if all links are correct at negative we should now have 11 degrees as well. This step is essential to finally check our setup. If more pitch is present in one direction, then something is wrong and we are getting some unwanted interactions, check and redo all of the links.

Cyclic Range

We are almost done now, and you will be able to breath easy. We want to adjust the amount of cyclic pitch available. Ideally we want 6 degrees in each direction, measured using a pitch gauge, the more pitch you have the faster the response of the model helicopter. As a beginner, you would be looking for a little less. As you have to add it to the total pitch of the blades in the first place.

So if you have set your blade pitch range to +/- 11 degrees, you will now have a total pitch range of 17 degrees. Way to much for a beginner. As with this amount of pitch, collective management whilst flying will be a big thing. To adjust these ranges, use the radios swash mix, aileron and elevator mix to be precise, reducing the number reduces the throw of the swash, and the same for the opposite direction. You may have to experiment a little with this to get the right balance.
But if you have followed this guide word for word, you should now have a well set up, and ready to fly remote control helicopter. Good luck!

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Align Trex 450 Pro Super Combo Review and Build Guide

2011-10-01T15:16:00.006+08:00

Introduction

The T-Rex 450 Pro Super Combo is the top end Align RC helicopter. It shares very little of the core parts with the 450 Sport and 450 SE V2 varieties. Utilising a completely different frame design. Also it incorporates a tail servo built into the main frame, as opposed to being mounted to the tail boom. It is aimed at the more advanced beginner or intermediate pilot due to its torque tube drive, as this provides more precise tail control, but also, increased costs in the event of a crash or boom strike. That being said, spares are plentiful, so this model can be enjoyed to its full potential without worry of high repair costs.

In keeping with the increased performance of the Pro version it comes with Aligns new more powerful motor, giving this little heli a very high head-speed, in excess of 3000 rpm. So it certainly has the power to allow the user to explore some more advanced routines. The performance will be talked about in greater detail later on in this guide, but for now it’s time to get on with describing the build and reviewing the model.

Build

In keeping with the 450 Sport, Align are pre-building these models partially at the factory. With varying results, so it is imperative at the very least to check every meta-metal screw or bolt for loctite, and also to ensure that all bolts are tightly fastened. But more so, it is wise to strip the pre-built parts down (head, tail, frame) and start from scratch. This way we can ensure a successful build. Hopefully Align will stop doing this (as it takes longer to take everything apart) and pack it in the same way as the 500+ helicopters in its range. But obviously purchasing a pre-built ready to fly package will mean all of this has been done for you.

The 450 Pro goes together very well, with very little deviation from the manual. To that point, the manual itself is very good, clear computer sketches of the build process. The manual also serves as a good reference for any adjustments the owner needs to do during the lifetime of the helicopter. It also covers the setup clearly of the ESC and gyro.

Initially we start with the head. Again this is pre built mostly. But it is wise to go over each screw and make sure loctite has been applied and the screw is firmly tightened. The main points to consider at this stage are getting the flybar positioned correctly, so we have an equal amount of length on both sides of the head. Also, when screwing on the paddles, making sure that they are set to an equal distance as there counterpart on the opposite side. Otherwise vibrations may be evident leading to flight control issues. All of the control arms except for the upper mixers to swashplate are of fixed length and solid plastic. This removes any potential errors in measurements, and leads to a more accurate and pain free setup procedure later on.

Next we construct the frame. Again, removing all the pre installed bolts, and re-building the frame. The next part is very tricky if unaware of the mechanics and order of the build. The servos are arranged in such a way that if you are leaving the frame built as it comes from the factory. It is necessary to remove some bolts from the CNC servo supports, pivot them, and slide into place the rear elevator cyclic servo. As Align have incorporated the servo mounts into the bearing blocks. Otherwise it’s impossible to get into place. Another point is we should install the motor before the servos, as it is almost impossible to access the motor bolts with the cyclic servos in place.

We need to ensure the motor is in the rite position before securing. So at this stage we slide in the main shaft and attach the main gear. So we can line up the motor pinion with the main gear. Leaving a small gap between the teeth, so they don’t wear with the constant friction of close contact. Despite the tricky nature of this section, Align have done a good job in the design and construction of this section of the helicopter. Removing the front plastic battery holder also makes this part easier. The build is as expected much more involved than described, but described here are just some of the points that require a little extra care.

At this stage it is a good idea to do a large portion of the electronics install. As removing the frames bottom plate we have good access to the helicopters internals and we can route the cyclic servos to the front of the helicopter. Placing the ESC in the front of the helicopter under the battery tray. Installing the electronics at this point allows for a much neater installation as when the head, tail, and undercarriage is in place access can be tricky.

It is always a good idea to power up the receiver, either with a receiver battery pack, or via the ESC (remembering to unplug the motor cables) and check for the centre position of the servos, cyclic and tail. The servo horns can then be fixed in place knowing that they are at the central 90 degree positions, it also allows us to bind the receiver before replacing the bottom plate of the frame and sealing away the electronics. As with a small heli like this we need to make the most of all the space we have, and it is very limited on space.

The Pro version of the 450 includes a torque tube drive. This makes the construction of the tail easier in some ways. As we don’t have to worry about tail belts. But we must make sure the correct installation of the torque tubes bearings, otherwise we may experience stripped gears or incorrect operation. In the simplest form, it is applying some CA glue to the central point on the torque tube, and then sliding on the bearing (without dust cover) and fixing the bearing to the centre. Being careful not to get any CA glue on the bearing itself as we don’t want to hinder its operation. Next we need to apply the rubber bearing seating/dust cover to the bearing. We then coat this in grease, and ease it into the tail boom, sliding it into position.

The tail unit is checked for loctite and built as per the manual, it is then locked into place onto the torque tube. Remembering to slide on the pushrod guide rings before attaching the tail boom to the tail block on the main frame.

Now we have the tail in place and secure we can attach the head unit, sliding it into the bearing block and fixing the main gear in place with the supplied bolt. It should fit snug to the motor pinion, as we checked for this earlier. Also, as we checked for the servo centre positions, we can go ahead and attach the control rods from the swash to the servos. During the build we set them to the length given in the manual. This can be adjusted later whilst setting up the helicopter.

The gyro is placed in position at the top of the helicopter on the provided mounting platform by the swash guide. Mounting of the tail servo is straight forward, two of the screws supporting its mounting can be removed and it then pivots out to allow the servo to be screwed in place.

So with the build almost complete, the overall construction and quality of the components is exceptional. All parts go together well, and are of a high quality. A good tool set is essential, as using wrong size hex keys can strip the bolts. Now we just need to set up the helicopter, and then we can look at its flight characteristics.

Setup

Setting up this helicopter is very straightforward, the supplied blades are made of good quality carbon fibre, and the supplied set required no changes during balancing. With the suggested pushrod link lengths the swash is near perfect, requiring only minor adjustments to make it level. As mentioned before, due to the majority of the links being a fixed length, there is little room for error. Spinning the helicopter up and checking the blade tracking reveals an almost perfect track. Requiring just a turn of one of the pushrods in order to bring it into line. Remember, blade tracking is a very dangerous job, so always wear suitable eye protection. As mentioned before though, with any pre-built package all of these setup procedures will already be complete.

The T-Rex 450 Pro, once complete and mechanically setup requires some programming of the radio, and then it is ready for flight. Giving it a gentle pitch and throttle curve will result in a nice flying experience for the beginner. More aggressive curves will give a crisper 3D experience.

The ESC comes ready to fly from the factory with the default settings suitable for this model and for all round flight. To confirm, double checking the audible cues at start up before spooling up the model. It’s also worth noting that the audible beeps are only heard with the motor plugged in, as it generates the noise. The gyro is very easy to setup, requiring very little input except for setting the servo travel distances and making sure the direction is correct.

Conclusion

The Align T-Rex 450 Pro is quite rightly not a V3 of the original 450 design. It is a whole new beast. To that end Align have done a good job, producing a lovely little model, with much bigger aspirations. The quality of the build is excellent, and the helicopter performs excellent out of the box. That is literally the case, all that is needed is a receiver, transmitter and battery. The rest is supplied in the super combo.

Due to the new more powerful motor being used it has ample room for performance flight. A seasoned veteran would get just as much use for this as the beginner. The supplied Align GP750 Gyro and 35A speed controller are a good pairing, providing a reliable electronic basis. Pairing this with a Helicommand unit (as shown in the photos) can give the ultimate beginner platform, super stable and not requiring massive amounts of land to fly it in.

The actual flight performance should be good, the 450 Pro was designed by Jason Krause, so it happily pumps out the power even at +/-15 degrees of pitch the head doesn’t get to bogged down and remains responsive. The value of the super combo deal is also very good value when comparing it to the costs of buying the items separately. All in all a superb all rounder, and sure to give hours of enjoyment.

_________________________________________________________________________________________

Controlling a helicopter

2011-09-30T21:51:00.000+08:00

Controlling a Helicopter

Helicopters require a completely different method of control than airplanes and are much harder to master. Flying a helicopter requires constant concentration by the pilot, and a near-continuous flow of control corrections.
A conventional helicopter has its main rotor above the fuselage which consists of 2 or more rotor blades extending out from a central rotor head, or hub, assembly.
The primary component is the swash plate, located at the base of the rotor head. This swash plate consists of one non-revolving disc and one revolving disc mounted directly on top. The swash plate is connected to the cockpit control sticks and can be made to tilt in any direction, according to the cyclic stick movement made by the pilot, or moved up and down according to the collective lever movement.
But first, to explain how the main rotor blades are moved by the pilot to control the movement of the helicopter, we need to understand pitch.

The basics of pitch

Each rotor blade has an airfoil profile similar to that of an airplane wing, and as the blades rotate through the air they generate lift in exactly the same way as an airplane wing does [read about that here]. The amount of lift generated is determined by the pitch angle (and speed) of each rotor blade as it moves through the air. Pitch angle is known as the Angle of Attack when the rotors are in motion, as shown below:

This pitch angle of the blades is controlled in two ways - collective and cyclic.

Collective control

The collective control is made by moving a lever that rises up from the cockpit floor to the left of the pilot's seat, which in turn raises or lowers the swash plate on the main rotor shaft, without tilting it.

This lever only moves up and down and corresponds directly to the desired movement of the helicopter; lifting the lever will result in the helicopter rising while lowering it will cause the helicopter to sink. At the end of the collective lever is the throttle control, explained further down the page.

As the swash plate rises or falls, so it changes the pitch of all rotor blades at the same time and to the same degree. Because all blades are changing pitch together, or 'collectively', the change in lift remains constant throughout every full rotation of the blades. Therefore, there is no tendency for the helicopter to move in any direction other than straight up or down.
The illustrations below show the effect of raising the collective control on the swash plate and rotor blades. The connecting rods run from the swash plate to the leading edge of the rotor blades; as the plate rises or falls, so all blades are tilted exactly the same way and amount.
Of course, real rotor head systems are far more complicated than this picture shows, but the basics are the same.

Cyclic control

The cyclic control is made by moving the control stick that rises up from the cockpit floor between the pilot's knees, and can be moved in all directions other than up and down.
Like the collective control, these cyclic stick movements correspond to the directional movement of the helicopter; moving the cyclic stick forward makes the helicopter fly forwards while bringing the stick back slows the helicopter and even makes it fly backwards. Moving the stick to the left or right makes the helicopter roll and turn in these directions.
The cyclic control works by tilting the swash plate and increasing the pitch angle of a rotor blade at a given point in the rotation, while decreasing the angle when the blade has spun through 180 degrees.

As the pitch angle changes, so the lift generated by each blade changes and as a result the helicopter becomes 'unbalanced' and so tips towards whichever side is experiencing the lesser amount of lift.

The illustrations below show the effect of cyclic control on the swash plate and rotor blades. As the swash plate is tilted, the opposing rods move in opposite directions. The position of the rods - and hence the pitch of the individual blades - is different at any given point of rotation, thus generating different amounts of lift around the rotor disc.

To understand cyclic control another way is to picture the rotor disc, which is the imaginary circle above the helicopter created by the spinning blades, and to imagine a plate sat flat on top of the cyclic stick. As the stick is leaned over in any direction, so the angle of the plate changes very slightly. This change of angle corresponds directly to what is happening to the rotor disc at the same time ie the side of the plate that is higher represents the side of the rotor disc generating more lift

Rotational (yaw) control

At the very rear of the helicopter's tail boom is the tail rotor - a vertically mounted blade very similar to a conventional airplane propeller. This tail rotor is used to control the yaw, or rotation, of the helicopter (ie which way the nose is pointing) and to explain this we first need to understand torque.

Torque is a natural force that causes rotational movement, and in a helicopter it is caused by the spinning main rotor blades; when the blades are spinning then the natural reaction to that is for the fuselage of the helicopter to start spinning in the opposite direction to the rotors. If this torque isn't controlled, the helicopter would just spin round hopelessly!
So to beat the reaction of the torque, the tail rotor is used and is connected by rods and gears to the main rotor so that it turns whenever the main rotor is spinning.
As the tail rotor spins it generates thrust in exactly the same way as an airplane propeller does. This sideways thrust prevents the helicopter fuselage from trying to spin against the main rotor, and the pitch angle of the tail rotor blades can be changed by the pilot to control the amount of thrust produced.

Increasing the pitch angle of the tail rotor blades will increase the thrust, which in turn will push the helicopter round in the same direction as the main rotor blades. Decreasing the pitch angle decreases the amount of thrust and so the natural torque takes over, letting the helicopter rotate in the opposite direction to the main rotors.
The pilot controls the pitch angle of the tail rotor blades by two pedals at his feet, in exactly the same way as the rudder movement is controlled in an airplane.
NOTAR is an alternative method of yaw control on some helicopters - instead of a tail rotor to generate thrust, compressed air is blown out of the tail boom through moveable slots. These slots are controlled by the pilot's pedals in the same way as a tail rotor is. To generate more thrust, the slots are opened to let out more air, and vice versa.
NOTAR helicopters respond to yaw control in exactly the same way as tail rotor models and have a big safety advantage - tail rotors can be very hazardous while operating on or close to the ground and in flight a failing tail rotor will almost always result in a crash.

Throttle control

The throttle control is a 'twist-grip' on the end of the collective lever and is linked directly to the movement of the lever so that engine RPM is always correct at any given collective setting. Because the cyclic and collective pitch control determines the movement of the helicopter, the engine RPM does not need to be adjusted like an airplane engine does. So during normal flying, constant engine speed (RPM) is maintained and the pilot only needs to 'fine tune' the throttle settings when necessary.

There is, however, a direct correlation between engine power and yaw control in a helicopter - faster spinning main rotor blades generate more torque, so greater pitch is needed in the tail rotor blades to generate more thrust.

It's worth noting that each separate control of a helicopter is easy to understand and operate; the difficulty comes in using all controls together, where the co-ordination has to be perfect! Moving one control drastically effects the other controls, and so they too have to be moved to compensate. His continuous correction of all controls together is what makes flying a helicopter so intense. Indeed, as a helicopter pilot once said...
"You don't fly a helicopter, you just stop it from crashing"!

MicroBeast Flybarless Setup

2011-09-29T13:21:00.003+08:00

http://rcheli-kjrc.blogspot.com/

MICROBEAST has an aluminum composite design casing. Its slight dimensions allow it to be installed in practically any model helicopter. MICROBEAST can be installed horizontally as well as vertically.

The sensory system is based on the newest MEMS technology. Software with sophisticated sensor data processing makes installation in electrical & nitro model helicopters possible.

With an optional adapter cable, MICROBEAST can also be utilized solely as a tail gyro. This is recommended especially for whoever is switching from the conventional paddle system and wants to slowly approach the RIGID operation with the 3 axle solution (3G-Gyro Mode).

The well-thought-out and easy setup goes smoothly with no need of an expensive programming box or computer. This makes it easy to still change a number of settings even at the airfield.

Moreover MICROBEAST's integrated swashplate mixer enables the use of simple remote control systems which do not have their own swashplate mixing (NO-MIX).

MICROBEAST is able to process many types of sum signals (PPM / S-BUS / Spektrum). With the optional Spektrum Satellite Adapter, installation in indoor model helicopters is also possible without a great number of wires.

Updates and advanced setup possibilities (Setups) can be done comfortably with the optional USB interface „USB2SYS“ via the BEASTLINK interface. Software for Windows & Mac can be downloaded free at www.BEASTX.com.

Microbeast V1 setup part 1

general considerations

Microbeast V1 setup part 2

Microbeast V1 setup part 3

Microbeast V1 setup part 4

Videos on individual Setup Menu Points:

Setup menu point A:
Mounting orientation of the MICROBEAST

Setup menu point B:
Swashplate servo frequency

Setup menu point C:
Tail servo center position pulse length

Setup menu point D:

Tail servo frequency

Setup menu point E:
Setting the Tail rotor endpoint

Setup menu point F:
Setting the Tail sensor direction

Setup menu point G:
Adjusting the swashplate servo centering

Setup menu point H:
Swashplate mixer

Setup menu point I:
Setting the swashplate servo directions

Setup menu point J:
Teaching the cyclic pitch geometry

Setup menu point K:
Adjusting the collective pitch range

Setup menu point L:

Adjusting the cyclic swashplate limit

Setup menu point M:
Setting the swashplate sensor directions

Setup menu point N:
Setting the pirouette optimization direction (by sutty)

Programming A Helicopter Remote Control

2011-09-29T11:53:00.002+08:00

We will try and describe the most common functions on a computer radio in helicopter mode. Note that the syntax may be different on different models and makes, but odds are it's there. I own futaba radios, so my terms will coenside with theirs. Some of these terms may be in the glossary as well.
You might also be interested in our article about Controlling RC Helicopters.
If you want you can skip to the Typical Beginner Setup, or the Typical Intermediate Setup, or the Typical Aerobatic / 3D Setup. Click here to Add Your Remote Control Programming Tips and read what other pilots have said on the matter.

The Switches

Idle Up 0,1, 2 (switch)

Idle Up 0, or Normal Mode as it's called, is for take-off and forward flight. Typically, this has the lowest RPM of the three idle-up settings which makes the controls less sensitive making it easier to hover with accuracy.

Idle Up 1 is your "sport" mode. It is for Fast forward flight, high speed turns with sharp cornering as well as loops and rolls. This has a slightly higher RPM, somewhere around 1600. Also, the bottom of the collective in this mode probaly won't be set for idle on the throttle.

Idle Up 2 is your aerobatic or 3d mode. Usually, this is a symetric throttle curve, meaning at full down on the collective, you're at full throttle so you can climb inverted. Then, in the mid stick, which would be 0 degrees of collective, you've still got plenty of power for doing tumbles.

Throttle Hold (switch)

This switch is used to disconnect the mixing of the collective with the throttle. By flipping this switch you can apply full collective pitch while having the engine stay at idle. You use this switch to practice autorotations and in the event of a tail failure. By cutting power to idle, the helicopter will stop spinning if the tail fails and give you a chance to autorotate to the ground. This mode usually has it's own pitch and throttle curve.

Throttle Cut (switch)

This switch is used to turn off your motor. Usually this switch only works if your throttle is at idle, or a very low position so that accidentily hitting it while you're flying won't force you to autorotate.

Trainer (switch)

This switch will let a second remote (plugged into your remote) take control of your aircraft so long as it's held. The moment you let go of the switch your remote is back in control. Usually, the instructor holds the remote that belongs to the flying aircraft and the student holds the extra remote.

Hover Pitch (knob)

This knob will let you adjust the pitch near the middle of the collective so that you can increase or decrease it. Ideally, you should be hovering around 6 degrees in Normal mode.

Hover Throttle (knob)

This knob will let you adjust the throttle near the middle of the collective so that you can fine tune your RPMs in a hover. Your target is 1550 RPM in a hover while in Normal flight mode.

Revolution Mixing

This mixes tail rotor with throttle. (which is mixed with collective) As you add collective you need more power to maintain your head speed, but once power is increased so is the torque which means you need to add rudder. This mix lets you program in some percentages so that the remote does most of the work for you.

To set this value you want to hover your helicopter and use your trims so that it does not spin in a hover. Then, after you land you want to program in or tweak your revolution mixing so that as you add or remove power while hovering the tail stays still. Which way you adjust it depends on which direction your rotor blades spin. In the U.S. they spin clockwise, so if you add power and the helicopter turns to it's right you have too much and need less mixing. These values require a lot of trial and error. If you have a heading hold gyro you must inhibit this function because the gyro will automatically compensate for anything including torque from the motor.

In 3D mode, your revo mixing should be a v-curve similar to your throttle curve so that as you add power for inverted hovering, you're also adding revo mix.

Throttle -> Needle Mixing

This will let you program in adjustments to the high speed needle valve at various amounts of throttle. Most people don't use this feature as it requires an extra servo.

Rudder Offset

This lets you set a different trim position for higher rpm modes, like idle-up 1. Since there is a higher rpm, there is more torque and thus will require a different trim setting to hold a steady hover. This is another trial and error function where you must land and tweak the settings. This function is also inhibited if you have a heading hold gyro.

Invert Mode

Not really used any more, this mode (when activated by a switch) would reverse the elevator and rudder controls so the helicopter would respond as if it were right-side up. You have to switch it back and forth as you go from right-side up to upside down. Don't use this!

Throttle Curves

Throttle curves tell the helicopter how much throttle to use at which collective setting. All radios come with a linear curve, so 0 throttle coorisponds to 0 collective, and 25% with 25%, 50% with 50%, 75% with 75% and full collective with full throttle. This linear "curve" rarely will maintain a constant RPM, which is your goal. You can fine tune your throttle so power is applied when needed to maintain a constant rotor speed.

There are many throttle curves, one for each idle up so that you can change how much power is applied with collective.

Pitch Curves

Pitch curves alow you to adjust the way the collective responds to the collective control. Most people leave it linear (0/25/50/75/100) but some people like to make the middle of the stick less sensitive (similar to exponential) for example 0/35/50/65/100. This way, the middle of the collective will be much less sensitive allowing you to hover more gracefully. It's up to you if you adjust these values, but bare in mind that you'll need to tweak your throttle curves in a similar way to maintain constant RPM. Pitch curves also have their own settings for each flight mode (idle up) as well as throttle hold. Some people have extra pitch (too much pitch for flying around) in throttle hold for that last bit of umph when landing with no power.

Programable Mixing

This will let you set up custom mixes from either switches or controls. You can for example mix power with cyclic, since every control movement takes power which will lower the RPM.

ATV

Adjustable Travel Volume lets you set the limitations on servo travel so that you don't "bind up" any controls. Thats what happens if your control arm can only turn so far, but your servo wants to keep going. This is hard on the servo and can break it, so you want to set the end-points to prevent it from happening. This is usually the first thing you set because it's the highest up on the priority for the servo movements. When the atv reaches it's limit there is no other function that can over power it to make the servo move more.

Sub-trim

You can use these to fine-tune the trim of your aircraft, or use them completely so that you can leave your trim settings centered. The reason you would want to do this is so you have full trim control at your finger tips if you need it, otherwise you might have to have your trim all the way left, and your flying along and something happens and you need more left you wont have any room on the trim lever. The sub trims let you always have room to trim it out in flight. It's best though to get the links physically set to as close as possible so you don't need to use sub-trims.

Reversing

This lets you reverse the responce the servo's move to the sticks. You would use this if right goes left or up goes down, etc...

Gyro Gain

This lets you set how sensitive you gyro is. If the gyro is set too high, the tail will wag like a dog's tail. If it is set too low it may be hard to control and wander all over. You want to set it as high as possible, but without getting it to wag. Remember that in forward flight the blades are more effective so it may still wag when moving even if it does in a hover. I usually use 5% less sensitivity that the best I can do in a hover because of this.

Exponential

This will make the center of the sticks less sensitive and the extreems of the sticks more sensitive, alowing gracefull hovering and snappy rolls. Most people use 15% to 25% expo, but it's only a preference.

Typical Beginner Setup

Normal Mode

Pitch Curve: 0 degrees / 6 degrees / 10 degrees
Throttle Curve: What ever it takes to maintain a constant 1550 RPM while in flight (including decents)

Idle up 1

Inhibited (Disabled)

Idle up 2

Inhibited (Disabled)

Throttle Hold (For emergency autorotations)

Pitch Range: -4 degrees / 6 degrees / 12 degrees

Typical Intermediate Setup

Normal Mode

Pitch Curve: 0 degrees / 6 degrees / 10 degrees (1550 RPM)

Idle up 1

Pitch Curve: -4 degrees / 5 degrees / 10 degrees (1650 RPM)

Idle up 2

Inhibited (Disabled)

Throttle Hold (For emergency autorotations)

Pitch Range: -4 degrees / 6 degrees / 12 degrees

Typical Aerobatic / 3D Setup

Normal Mode

Pitch Curve: 0 degrees / 6 degrees / 10 degrees (1550 RPM)

Idle up 1

Pitch Curve: -4 degrees / 5 degrees / 10 degrees (1650 RPM)

Idle up 2

Pitch Curve: -10 degrees / 0 degrees / 10 degrees (1750 RPM)

Throttle Hold (For emergency autorotations)

Pitch Range: -4 degrees / 6 degrees / 12 degrees
Pitch and throttle curves are totally personal preference though. These are only possibilites. I myself fly all modes with the same pitch range (-10 degrees / 0 degrees / +11 degrees) This way I'm totally used to how the collective responds through all flight modes and it never changes. Many people actually prefer it this way, although it's the most sensitive on the collective. It requires very subtle movements to climb or decend in a hover rapidly.

Setting Up the Helicopter

First, you make the mechanical connections. You want to set up your links so they use as much physical movement on the servo and are close to centered as possible, then you use your radio to fine tune it.
The reason you do this is to get the most "resolution" out of your servos. They only have so much accuracy, and the more travel you can use physcally, the more accurate your controls will be.
As an extreme example, say you have your servo geared so that only 1 degree of motion would move the rudder full deflection. Then the servo must be very accurate to smoothly transition from one side to the other. This isn't the case, there are only a finite number of steps the servo can move, and the more you use, the smoother control you will have.
Also, the more throw you can use, the more leverage and thus power your servo will have.
Second, tweak the connections so that mechanically they conform to the list of pitch ranges above; if you're a beginner, use the beginner pitch ranges etc... Ok, now say you get your pitch range to be -1 / 8.5 / 12. I would slide your mechanical adjustments a bit (by adjusting the links) to be more focused around 6 degrees in the middle. 6 degrees is the optimal hover pitch, because if you're hovering and your blade pitch is 6 degrees, you must be using a good rpm from 1500 to 1600 which is what you want and when you're a beginner, you want to hover at the middle of the stick. If you're at -1 / 8.5 / 12, change the links 2 degrees until you get to -3 / 6.5 / 10. These are more pratical values, closer to what you want went learning.
Thrid, use the atv settings so that you can use as much as the servos as possible, but below the point at which they bind. (Binding is when the link goes as far as it can mechanically go, but the servo tries to move it further)
Before you start actually flying, you should set up your throttle hold and kill switch if you have them. These are saftey features and might save your helicopter or the skin on your back. Set your throttle hold so it has just enough throttle to idle smoothly. You can use this (or kill) if you know you're going to crash or while you cary your helicopter out to the landing pad.
Fourth, set up the pitch curve settings on the radio to make your helicopter accurately conform to the pitch range that suits your skill level. The only reason you want -1 insted of -3 or -6 on the bottom is because no newbie is used to how sensitive the collective is and so is destined to slam it into the ground when they panic and move the left stick down more than they should. By setting this value to a high number (high as in 0, or -1 degrees compared to -4 or -10 like I use) you minimize the damage you'll do when you first panic.
Once your pitch range is set up and accurate, you only adjust the throttle curves from then on. You do not adjust them both here and there then and again. This makes it confusing and impossible to "home in" on a good setting. One problem at a time, so start with pitch, get that set, then work your throttle curves until you get a constant rotor rpm.
Fith, If you have a gyro that is NOT heading lock, you'll need to adjust the revolution mixing (revo mix) function on your radio. This is a two step process; first you must set the 0-degree mid point as a starting refrence. Once your helicopter is set up not to yaw at 0 degrees, you configure the ratio of power to rudder mixing you need when you add or take away throttle. Your helicopter manual should tell you what aproxomate settings to start with. It's difficult for a newbie to set this portion of their radio up, because the best way to do it is to fly up and drop the collective to 0 degrees. The helicopter will drop very fast, but by watching which way the helicopter turns on it's way down you will find out if you need to add more mixing or less mixing. This 0 degree fall is used to set your anti-torque at the lowest point of torque. After that, you set the mixing percentage of throttle to rudder; that is, the more power the more you need the radio to correct for the torque by adding rudder automatically. Same for decending, when you need to take rudder away while there is less or no torque.
After that, you can set expo if you like. This will help soften the center of the sticks so you don't over react, but leave room for the hard yank and bank you may need in an emergency.
After you get used to the sensitivity and don't over-react, you'll want at least -4 degrees on the low end so you can do an autorotation if you have to.
Eventually, you'll want all the range you can get, symetric if possible. I fly -11 / 0 / 11 on my raptor. On the nexus, I could only get -6.5 / 2 / 8.5 because of the mechanical design limitations. This is barely enough for inverted hover and minimum positive pitch for autorotations.

RC Heli Flight School

2011-09-23T18:26:00.019+08:00

What is 3D....
3D is a style of helicopter flight which makes the helicopter appear to defy gravity by flipping , rolling and moving in “3 dimensional space” sometimes on the spot, which would not otherwise be possible in full size helicopters. There is not really a clean explanation of what 3D is …often a video helps.

Auto – Pushover

Start out in an inverted auto and then pushover to a tail first landing. The key to this trick is getting the right amount of forward speed while inverted. Start out high to get the Fwd speed and timing correct.

Auto – Tumbling S

Another trick to be performed while autoing

Sustained Pirouette Flips

Pirouette while flipping which is essentially keeping the cyclic in phase with the yaw of the helicopter in order to maintain the flip. Repeat the maneuver over and over and you have your: “Sustained Pirouette Flip”

Chaos Again this involves Piro-Flips however this time between each individual Piro-Flip, the axis of the flip is rotated. You follow the same principle that is being applied in the Piro-Globe.

Death Spiral

As the name suggests this can be a quite dramatic maneuver when performed to the limits.

Start with plenty of height in a stationary hover then 1/4 roll the model to knife-edge then Set collective to 0 deg. As the model falls apply fwd or bwd cyclic. The model will be rotating about the axis which it is falling. To exit, stop the application of fwd/bwd cyclic and 1/4 roll again. Depending on the direction you roll out, will lead to a normal or inverted pullout.

The rate of descent can be slowed by applying the Stationary Death Spiral philosophy.

Death Spiral – Stationary

The stationary death spiral is a development of a Fwd inverted circuit. By decreasing the diameter of the circuit until the model is effectively turning on the spot. To sustain height the model obviously isn’t knife-edge, as with the death spiral. However the model is at a very steep angle.

Once the stationary death spiral has been mastered the heli can be sent round circuits and climb in this manner, with the use of collective.

Detonator

One of the 3D Masters set maneuvers. See pic. Basically a climbing then falling funnel. But, for this manoeuvre a skids in and out funnel are required.

Start in a Funnel, skids IN, and low (tail down for this example). Then power up vertical, maintaining the funnel. At no point should the diameter of the funnel increase/decrease.

At the top put the model Knife-edge tail down, but keep rolling the heli. Then transition to a funnel but this time skids OUT. Now bring the heli back down to the starting point, in the funnel.

For clarity the upwards and downwards section are shown side-by-side in the picture. But, the idea is to go straight up, then straight down. Like the Plunger on a ‘Detonator’.

Funnel

See Pic. The example shown is tail-down inverted. This seems to be the most popular variant. But there are of course many different variants.

The funnel is a development of sideways circuit flying. By reducing the size of the circuit until the tail (in this example) is turning almost on the spot. Increasing the collective pitch while still maintaining height will force you to increase the angle of the model, and vice-versa.

The transitioning between the different variants of a funnel, is known as morphing funnels.

Hurricane

The ‘Hurricane’ is a high speed knife-edge circuit (Basically the same as a Wall of Death).

By using high collective values the angle of the model can be made to appear on the knife-edge.

TIP: By flattening out the circuit @ positions B/D allows more lift to be created, so that @ positions A/C the model can actually be put on the knife-edge. As A/B are the positions at which the spectators view the model on the knife-edge, it increases the illusion that the model is knife-edge all the way round.

Hurricane – Flipping

Move is seen in the picture from birds eye view

Tic Toc

A metronome is a way of achieving ‘knife-edge’ flight with a helicopter. See Pic. When viewed on (A) it appears that the heli is holding a knife-edge attitude. Also known as a Tic-Toc. Using the metronome as a flight mode, it is then possible to perform, metronomic circuits, Figure 8s, Loops and the Big Ben Clockface.

Pie Dish

Similar to a funnel but the size of the circuits is much bigger and the angle of the heli is lower, giving the ‘pie dish’ shape to the man’vre.

Pirouetting Globe (picture from birds eye view)

Enter maneuver pirouetting traveling E to W.
When central (C) to pilot/judges start Piro-Loop (PL1) travelling E to W.
Complete PL1.
When back at the center (C) rotate direction of travel by 45°.
Perform PL2, starting loop traveling NE to SW.
When back at the center (C) rotate direction of travel by 45°
Perform PL3, starting loop traveling N to S. (i.e., looping into yourself to start).
When back at the center (C) rotate direction of travel by 45°.
Perform PL4, starting loop traveling NW to SE.
When back at the center (C) rotate direction of travel by 45°.
Perform PL5, starting loop traveling W to E (Parallel to flight line).
Once PL5 is complete exit maneuver traveling W to E pirouetting.

So you enter and exit the maneuver at the same point (C), but exit traveling in the opposite direction.

Now you could decrease the angle of rotation change to say 30°, 15°, 10°………etc. Therefore increasing the number of piro-loops to the globe. To make it look good, I think a 45° change is the minimum requirement.

The other variation is to continue rotating by another 45° after PL5 and continue round. This would give 9 piro-loops and exit traveling E to W. This is gonna be hard, because you now have to be able to piro-loop away from yourself.

Pirouetting Loop

The example shows 2 complete pirouettes per loop, you can of course do as many piro’ you like per loop. The pic shows a piro-loop, using right tail rotor input.

Pirouetting Outside Loop

The outside version of the pirouetting loop.

Pirouetting Vertical 8

One of the 3D Masters set maneuver.

Pitch Pumping

Not really a man’vre in itself I believe. Pitch pumping has arrived with the advent of big block powered machines, were pitch can now be used to add a dramatic visual effect to a more ‘traditional’ maneuver. As it sounds, pitch pumping is basically moving the collective from say -5deg to + 5deg in rapid succession.

Rainbow

A rainbow is basically a large 1/2 flip but holding the collective until the end of the flip. By varying the amount of cyclic and collective determines the size of the rainbow. The rainbow can be carried out Fwd/Bwds, Sideways and Piro’ing.

Ripper

Basically a Pirouetting Tail Slide. As the falling speed increases, the demands on the tail system become VERY HIGH. Only attempt this maneuver if you are 100% confident in your model.

Slapper

3D Masters Move – This maneuver consists of a series of tailboom-vertical metronomes with a half aileron roll between the metronome stop points. 6 pitch reversals are required, and the model will retain constant tailboom orientation. The roll will be centered at the mid-point of the arc.

Snake

The snake is performed on the ‘knife-edge’. Pic shows a birds eye view.

To perform the example shown, you need to be able to perform (1) A tail-first inverted clockwise knife-edge circuit and (2) A tail-first normal anti-clockwise circuit. Then bring the 2 together and perform 1/2 circuit (1) then transition to the other (2), and so on down the flight-line.

Like most tricks there are multiple variants to practice and master. (NOTE: Pic shows the heli completely knife-edge, this obviously is not possible, but it was much easier to create the pic that way)

Sudden Stop

One of Jason Krause’ signature moves. First get the heli traveling at great speed Fwd Normal Flight. Then pull back elevator quickly and do a 1/4 back flip to vertical, then punch more positive collective. The heli will suddenly stop its Fwd motion. The key to getting a dramatic sudden stop is the cyclic to collective timing.

Tail Slide

Take the model up high and then point the tail at the ground. The model will accelerate and end up falling tail first very fast !!!

Tornado

The Tornado is a combination of a pie dish up-high morphing into a funnel down- low.

Wall of Death

The Wall of Death is basically the same as a Pie Dish, but with the heli at a near vertical attitude.

Waltzer

Another one of the new 3D Masters Set Maneuvers

The maneuver involves performing multiple funnels while sending the heli around a circuit.

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Heli Flight school

Below you will find links to videos that will guide you through learning how to fly an RC Helicopter. These short heli training videos are geared towards getting your RC helicopter up in the air fast by showing you what to practice. Following these steps and practicing each level will build muscle memory, orientation, sport flying, 3D skills and give you the confidence you need to improve your rc heli flying at the field. The intended audience is sport to intermediate 3d pilots. Even if you are doing 3d moves test yourself and see if you have any weaknesses in these levels. Make sure you practice and master each level before you move up. In just 30 minutes a night or less you can learn to fly an RC helicopter and become a master 3d heli pilot.

Practice 30 minutes a day and try to master every move before moving up a level. It may take weeks to master a level and you will crash a million times before some of these moves click. Keep trying every night!

Level 1 – Hovering upright

This video describes some of the first steps to learning radio controlled 3D flight. It is important that you have a solid foundation of skills in order to advance to the next level of flying. When I first started I searched high and low for information on how to learn to fly 3D. What I found was a lot of outdated information from an era before simulators. Hopefully this video series will help guide people on how to advance quickly with a simulator.

Remember to slowly transition what you learn in the sim to the field. Things don’t always go as well in real life. But learning tail-in, side-in and nose-in hovering will really boost your confidence and get you started.

Learn upright hovering, rudder control and orientation. Hovering side on, tail in and nose in be difficult. This video shows you in a few minutes what to practice to hover an RC helicopter upright. Practice:

Tail at 45 degrees offset
Side in viewing the helicopters left and right side
Nose in with the tail directly away and offset
Stretch: Pirouette back to tail in. Backward flips
Bonus: Forward flight circle

Level 2 – Hovering inverted

Learning to hover inverted can be challenging and frustrating. But in the last few years simulators and computers have really advanced. So learning to fly upside down can be as easy as upright. If you want to learn to fly 3D and are just getting started make sure you start on this step within the first couple of months. Once your brain realizes that RC helicopters can hover upside down as easily as upright you will be well on your way. Make sure you practice Nose in, side in and tail in inverted hovering.

It will take some time for this to sink in completely. Just keep practicing 30 minutes a night and it will come to you. When you first try this at the field make sure you have a lot of altitude and know which way you want to bail out.

Inverted hovering is difficult because our brains don’t want to believe a heli can fly upside down. Follow along on this video and master rudder control and the soft feel you need to hover an RC helicopter while inverted. Practice:

Tail offset 45 degrees on each side
Side in looking at the heli on the left and right
Nose in inverted
Stretch: Forward flips, Rolls, Inverted piro to tail nose in.
Bonus: Inverted forward circle

Level 3 – Flying in circles

Finally the start of some real flying. In this step you will learn to fly in circles. It is really important that before you move into this level that you have a really good grasp on upright and inverted hovering. If you can’t hover in an orientation you can’t fly in it. A lot of people get started learning figure 8’s first but I like to focus on circles first. The reason is without good practice in grooving a circles you end up doing lazy figure 8’s. In lazy 8’s the circles are elongated and cross like an x in the middle. If you learn circles first you will be able to focus on the transition in a figure 8 and not so much how to maintain flight. I’ll leave it for a later lesson but the transition in a figure 8 is the key to a lot of 3D flight maneuvers.

Keep up your hard work on this lesson. You will likely crash every time but just keep trying the flight directions equally. It will pay off in the end and you will eventually get it!

Learn to fly an RC helicopter in circles and keep it on a constant heading without increasing to decreasing in speed. Controlling the cyclic and elevator movements you will learn to groove the heli into a circle and keep it there. Practice:

5 forward circles left and right
5 backward circles left and right
5 inverted forward circles left and right
5 inverted backwards circles left and right
Stretch: Forward loops, Backward loops,Tail down tic tocs
Bonus: tail down rainbows, stationary piros

Level 4 – Flying in Figure 8’s

In this video lesson you will go through how to learn to fly figure 8’s. This is the next step beyond learning to fly in circles and will help you groove in your circles even better. Figure 8’s are great to practice to improve your orientation and advance your 3d flight. In the bonus section you will see morphing figure 8’s, stall turns with changing orientation and side on tic-tocs. Make sure you practice this every night and keep trying until you can complete 5 figure 8’s in a row without crashing in each orientation.

Once you complete circles the next step is to learn to fly an RC helicopter in figure 8’s. The main thing you are learning is the transition between one circle to the other. Don’t cheat and do lazy 8’s make sure you come around in as perfect a figure 8 as possible. Practice:

Switch this move so the figure 8 crosses towards you and away from you.
Forward
Backwards
Inverted
Inverted backwards
Stretch: Snake transition in figure 8 with 30% bank angle, Side on Tic-Tocs
Bonus: Stall turns changing orientations at the top of the turn

Level 5 – Learning funnels

Learning funnels can be challenging work. Once your have a solid foundation in circles and figure 8’s a natural place to go is funnels. But most people get discouraged by how unnatural this flight direction can be. This video will walk you through how to get started learning funnels. The video also emphasizes a training plan that has you perform 5 funnels in a row in each flight orientation until you have mastered the skill. Learning to fly funnels can be a lot of fun and trust me your brain will give up eventually and agree that sideways flight is possible.

Something about remote control helicopters in sideways flight looks cool and seems so wrong to our brains. Think about doing circles and focus on grooving in your funnels. The key is to reverse your aileron and elevator cyclic movements from a circle and let them go. Practice:

5 upright tail down, left and right
5 upright tail up left, and right
5 inverted tail down, left and right
5 Inverted tail up, left and right
Stretch: Funnel figure 8’s
Bonus: slowing down funnels and changing the speed

Level 6 – Learning loops

Learning how to fly loops in every orientation is essential for the developing 3D pilot. In this video you will learn how to fly loops in every direction and get key insight on how to perform the loops. Make sure that you keep the loops parallel to yourself and the flight line. This will be key later in your flying when you start to mix loops into your routine. Also, it looks much more impressive when you have the loop centered in front of yourself and the heli is side on the entire move.

Make sure you practice this for 30 minutes a night until you can perform at least 5 loops in each flight direction without crashing. And when you get to the field start off by trying these loops high enough that you can recover if you make a mistake or get disoriented. As with the previous videos in the Flight school training guide this is a fly along video. Basically you want to practice exactly what I am doing in the video.

Enjoy and good luck

Performing large loops with an RC heli can really be fun. Work on these and controlling your inputs on the simulator before you go the field. Also remember with a flybared helicopter that you will need to give constant cyclic inputs during a loop to keep everything in sync. Practice:

5 inside forward, left and right
5 inside backward left, and right
5 outside forward, left and right
5 outside backward, left and right
Stretch: Vertical loop figure 8
Bonus: Sideways loops

Level 7 – Morphing or Transitions

At this stage you have developed a good base level of skill in hovering, circles, figure 8’s, loops, rolls and flips. The next step is to work these moves into your 3D heli routine by morphing from one flight orientation to another. In the old days it was difficult to practice this. But with the use of a simulator and regular practice you will be switching orientation right in the middle of a figure 8 or hurricane. Doing transitions and morphing between orientations really adds an interesting piece to your flight plan. Start by practicing half flips and rolls until you are comfortable. then add rudder until you can perform a roll and go from tail in upright to tail in inverted. If you have trouble stabilizing the heli after this maneuver then you should go back and practice hovering.

Learn to fly figure 8’s, hurricanes and the mobius with your RC helicopter. The video lesson will show you how to practice morphing from one orientation to another in flight. Follow the video and steps below and practice:

5 of each figure 8 morphing orientations
Forward upright to inverted going left and right
Backwards upright to inverted going left and right
Upright funnel to inverted left and right
Verticle loop figure 8’s left and right
Horizontal loop figure 8’s going left and right

Level 8 – Rolling travel

Rolling in a straight line forwards and backwards
Rolling circle forward left and right
Rolling circle backwards left and right
Rolling figure 8’s

Level 9 – Pirouetting travel

In this video lesson you will learn how to break down and practice pirouetting moves with an RC Helicopter. First you will work on hovering while pirouetting and move into piro travel in a straight line and eventually piro circles. Following piro circles you will start to work on the move everyone wants to do at the field the famous piro flip. Once you have a good grasp of the piro flip you will work on morphing piro flips and piro snakes.. anything is possible.

Remember nothing is as hard as you think. It might take you a very long time to get this down possibly even months just to piro hover. Stick with the training because one day your brain will get the movements and it will become automatic. I have been working on this move for 18 months now and as you can see I still have flaws in my skills.

Enjoy and good luck.

Flying an RC helicopter while is is pirouetting can be challenging. This video will walk you through how to learn to fly your RC helicopter while it is doing a piro. Or as most people describe it this the video with show you how to fly piro moves with an RC helicopter.

Pirouetting in a straight line left right, inverted
Piro circle upright
Piro circle inverted
Piro flips
Piro Figure 8 Upright
Piro Figure 8 Inverted

Level 10 Direction

Go back and practice all above in the direction you were most uncomfortable.

Level 11 – 3D Genius – Mastery

4 point tic-tocs and traveling tic-tocs
Death spiral and low tail slides
Flappers
Piro Rainbow
Piro Snake
Piro Loop
Piro Tic-Tocs
Big Ben
Piro flip Reversal
Pitch Pumping
Flipping Hurricains (circles)
Slinky (circle, 45deg circle, edge loop (viewed as loop from side), 135deg circle, circle)
Smackdown Flying
Smooth transitions between moves

Level 12 – Unbelievable stuff

Chaos (piro flip with rotating axis)
Piro Snake Figure 8
Piro Globe
Fliping Funnel 8
Reversing Piro Tic-Tocs
Reversing Piro Rainbow
Reversing Piro Snake
Kruezenburger
Reversing Piro Funnel
Wheel of Fortune
London Eye(piro tic-toc loop)

Piro Vertical Figure 8
Piro Slinky (variation of globe where you start with piro circle (start at left or right side of pilot), piro 45deg tilted circle, piro loop, piro 135deg tilted circle, piro circle (opposite side of pilot from the first circle)

Autorotation

An autorotation is a procedure where a helicopter can make a controlled approach and landing after motor failure, or deliberately cutting the power mid-air with the throttle hold switch on the transmitter.

An autorotation consists of two phases. Immediately power is lost, the collective is lowered and the pilot establishes an autorotative glide, where air flowing through the main rotor from bottom to top causes the rotor to maintain RPM (much like a windmill) and generate sufficient lift to make a controlled descent. As the helicopter approaches the ground, the pilot executes a flare, converting the helicopter's forward speed into additional rotor velocity and lift, and allowing the helicopter to establish a brief hover before landing, or perform a gentle running landing.

The main rotor is able to freewheel during autorotation due to a one-way bearing in the transmission. Depending on the location of the one-way bearing in the transmission, the tail rotor may (or may not) be driven from the energy gained by the main rotor, making it easier to maintain or change the helicopter's heading throughout the autorotation.

Autorotation performance is greatly affected by the size of the helicopter. 450-size helicopters can be autorotated but there is very litte spare energy at the end of the approach. Larger helicopters, such as 600 size machines, are much easier to autorotate and have much more hang time---the amount of time the helicopter can hover before the main rotor loses useful lift---making the procedure much more tolerant of error.

Autorotations can also be performed inverted (with positive collective pitch added): often the inverted section will be flown backwards, to enable the flip to upright to be made a part of the flare while minimizing the risk of hitting the tail on the ground. Another variation are blade stop autos, where the pilot deliberately adds positive pitch to slow the main rotor almost to a stop, then gives negative pitch to spin the rotor again---hopefully giving enough energy to complete the autorotation with the helicopter in on piece.

Autorotation practice is typically started by performing hovering autorotations from no more than 1 meter above the ground so the pilot can learn how much energy is stored in the main rotor. As the pilot becomes more confident, short practice autos can be performed from 1-3 meters in slow forward flight in approach for landing. Ideally, autorotations are performed into the wind, as the increased airspeed will give the helicopter increased translational lift. In practice, the engine may fail at inopportune times!

An autogyro is an aircraft that generates all its lift by a constantly autorotating main rotor, with forward power provided by a pusher prop.

Pilot : Zahidin Mohd Zahid
http://www.facebook.com/zahidin.zahid