Getting Started with Helicopters - Part 1

So you want to learn to fly helicopters eh?. (You fool :-)

If there is one thing you should be clear about before you start to get involved with helicopters, it is that it requires time and comitment (and a few quid). I will never regret the day that I decided to go ahead and learn this fascinating discipline but nothing could have prepared me for the amount of practice required (or maintenance for that matter) as I had already been flying for some eight years with both gliders and powered aircraft. I found that I was in a position where I pretty much had to teach myself to fly these machines as information was quite thin on the ground in my area even as recently as six to seven years ago, You definately need some sort of help/tuition. If you take the solo route you endanger the model, people around you and yourself.

My two principle aids in this process where a book by Dave day called Learning to fly model helicopters and his associated videos From the ground up and Beyond the hover. I have to say that I found both of these invaluable.The book because it described the workings of the helicopter in great detail and the videos because they took you step by step through the learning process.

FROM DAWN TO DUSK.........

Showing all the stick movements required to acheive the desired results was a great help. This was coupled with a chaptered format whereby you could watch a chapter and then go and practice that manouver until you got it just right before proceeding.

Regardless of anything you have heard in the past my advice to you would be to get one of the hirobo shuttle range as pictured above this little machine is to my mind the ideal way to start. All spares and upgrades are readily available and some very good package deals can be found.

Shopping List :-

1. Hirobo shuttle zts £170.00 approx at time of writing
2. Engine O.S 32SXH £111.50 or Irvine 36H r/c £74.95 . if you can afford the O/S I would recommend it ( what price reliability ? )
3. Radio well.. You just cant beat futaba in my opinion FF8/6 £399/199 respectively the FF8 is a little more extravagant but eventually you will appreciate the extra usability I have found that some very useful extra functions are available on the 8 version. J.R radios :I have only limited experience of these but reports are good. However when setting up choddys set I found that the instructions werent so helpfull and we had to look else where for advice .XP-652 £199.00 /X-3810 ADT £484.00 Please remember there are cheaper options available but these transmiters will keep you in good flying fettle for many years to come and can store the settings for all your models on one transmitter.
4. Gyro GWS PG0-1 . £30.00 approx. Excellent little unit the size of your thumb.
5. NI - CAD battery 1900Ma-H Around £20.00 and this capacity gives you plenty of practice time
6. Flight box, Starter, Power panel, Battery, Charger, Fuel . Around £110.00
7. Training undercarriage.£10.00 approx.
8. flying Model helicopters (Book) £8.75 From Slough R/C Models.
9. Videos. From the ground up £12.99, Beyond the hover £12.99, Intro to model helicopters £12.99 From Slough R/C Models.

And that should be quite scary enough for now .In truth most people in the beginning would go for a starters deal at about £500.00 but I always find one or two bits that i would rather spend the extra on with hindsight. Also as I'm a cheapskate I would go through the classified adds at the back of the magazines and buy second hand. there is usually a full setup for sale hardly used at a bargain price, if you decide to go down this route PLEASE... PLEASE take some one with you who knows what they are doing. And take the time to shop around. your spending a lot of cash.

Well most of the manufacturers supply very good scale body kits, but as these are an added extra cost and the fact that during the early learning phase there is a higher risk of crashing your model, a scale body is best left until you have more experience. As you can see from the pictures there is a vast range to choose from and various levels of skill and complexity involved in putting them together. Some with working retractable undercarriage, winch gear, lighting systems and much more.

Bell 47 by vario..

Something that as you progress you will however wish to consider is upgrading the standard parts for more durable metal options for your helicopter. Amongst the most obvious of these is carbon fibre or fibreglass rotor blades, as these usually come prebalanced and reduce the constant need for tracking the blade tips due to temperature and moisture changes in the wooden blades. Also swashplates and cooling fans, bearings and tail boom supports are quite useful in increasing the performance of your machine.

Before we get on with the buisiness of learning to fly the beast, it is worth taking a look at how the control system works. Unlike a fixed wing aircraft a rotary wing has to alter is path through the air with both great accuracy whilst spinning at incredible speed. Imagine that the rotor is 1mtr. long and turning at 1,300 + rpm the tips of each blade are travelling at hundreds of miles per hour.When compared to the relatively slow fixed wing/control surface combination moving at 30 + miles per hour you can see why a very complicated and precise method of control is required to operate such a system. Also coupled with this, you then have the additional problem of the torque reaction from the engine turning against the main blades on the fuselage which then translates through to the fuselage of the aircraft and tries to rotate it in the opposite direction. This is controlled by a much smaller but very similar rotor system at the tail which leads us nicely on to our first subject.

The tail rotor is a smaller set of blades at the end of the tail boom.These are driven through a reduction gear taken off the main drive (usually after the clutch side of the main gear) and then either a shaft, wire or belt drive connects to yet another gearbox at the back end which allows the tail shaft to be at 90deg. to the boom.

I would recommend a belt driven tail as this is far more likely to survive the dreaded boom strike. Whats that ? I hear you all cry. Well, its when all the nastiest aerodynamic forces in the world conspire to bring the main blades into contact with your tail boom and tie it in knots. Just try and push (not too hard) your blades down to meet the boom by hand and you will see the sort of force I'm talking about.

Yes you guessed it the Shuttle has a belt drive (and so does the Thunder Tiger Raptor. I will be reviewing this heli very shortly.) and Im hoping that Mr Hirobo will send me a freebie. But seriously, as a beginner this may happen in a moment of distraction as you try to master the hover or early manouvers and circuits.

This unit is the tail rotor equivalent of the swashplate and is used to convert linear to rotary motion. It has both a static and a rotary part, the two being connected by a ball race (see figure 2.). As the pushrod from the bellcrank operates, the tail slider moves along the shaft and increases or decreases the pitch on the blades. Fig 2. may be slightly misleading in as much as I have shown both conections to the blade holders on the same side for clarity. these should of course be on opposite sides to each other, so that they do not both turn the same way.

Although much larger the main rotor control system is remarkably similar in its operation.The main difference being that as well as increasing and decreasing pitch it also tilts the blades from side to side and back and forth. This is achieved by having a ball joint in the centre of the swash plate (equivalent of tail slider) which then through a series of levers and pushrods tilts the paddles on the fly bar. This acts as a form of power steering and tilts the main blades through yet more levers and rods.

If you refer to figure 3, you can see the swashplate mounted on the ball joint which slides up and down on the main shaft this portion of the swash remains static. The top part of the swash and all parts above this point rotate along with the head and blades.

As all these actions come together the result is that the flybar paddles are tilted, and in the same way as if you tilt a wing up or down the paddles rise or fall depending on which way the swashplate is tilted. The centre section of the flybar is linked to the blade holders through another set of levers and as it rocks from side to side changes the angle of the blades. If you look at fig 4. you can clearly see this linkage to the far right of the fly bar centre section.Not only does the swash plate tilt to roll the aircraft but it moves up and down.This effectively increases the pitch on both blades simultaneously to give more or less lift to the helicopter. Also if the blade pitch is reversed after an engine failiure the head speed can be maintained as the helicopter descends through the air until a safe height is reached to re apply the pitch for lift and therefore allowing a normal safe landing under control.We call this manouver AUTOROTATION..

Getting Started With Helicopters Part 2

Article by Grot from Bumpy Green Model Aerodrome
1th June 2001