February 19

Flying RC Model Planes – Taking Off

There is a saying in the world of model airplane flying that goes something like this:

LANDINGS ARE COMPULSORY, TAKE OFFS ARE OPTIONAL!”Ready to Take Off

Whenever you decide to commit your model to a take off, the onus is on YOU to ensure everything is as it should be for a safe and enjoyable flight.

What this means is that flying rc model planes is not just about opening the throttle and getting the plane airborne. There are a whole sequence of procedures that need to be checked before you get to this point.

Before I get to talking you through the process of how to take off your model airplane, I need to discuss the checks you must to carry out before flying. Failing to make these checks will inevitably result in either a malfunction or the chance that your plane will be so uncontrollable as to be unsafe to fly to say nothing of your frustrations.

Pre-Flight Check List for RC Airplanes

It is as important for RC Airplanes  to undergo Pre-Flight Checks as it is for full size airplanes. You need to check everything you possibly can to reduce the risk of crashing your model.

Frequency Check

Although most people are using 2.4GHz radio control systems today, there are still a good number that still rely on the 35MHz frequency in the UK and Europe whilst in the USA, 72MHz is still used by some. If you are using any of these (or other) frequencies it is essential that you check the compatibility of both Transmitter and Receiver crystals in your gear before you go flying.

Once at the flying field you should check with all other flyers that they are either on 2.4GHz or that their chosen frequency does not clash with yours.

Radio Range Check

It is so important that you getRange Check into the habit of carrying out a range check prior to every flying session. It should be done before the first flight of each day at the flying field. Follow the procedure as explained in your radio manual for doing a range check.

Those of you who are still using 35MHz or 72MHz or other MHz frequency radio gear should collapse the transmitter fully to carry out this check. 2.4GHz transmitters have a dedicated switch position (usually the buddy box training switch) and a programme setting for this purpose.

Check the Balance

You should always check that the model balances at the correct CofG point prior to every flying session. There is always a possibility that something may have shifted within the fuselage to effect the balance point. Don’t assume this has not happened.

If this is to be the first flight with a new model, be sure to check that it balances laterally and that one wing is not considerably heavier than the other.

If yours is a Glow/Nitro powered model, carry out these checks with the tank empty. It is better that the model is slightly nose heavy with its fuel load than to go tail heavy as the fuel is used up.

Check Engine and Wing Bolts for Tightness

It is not impossible that engine vibration during previous flights may have caused the engine bolts to work loose.

Although you may have fitted the wings just prior to this flying session or at home before travelling to the field, it is wise to double check that the wing bolts (if used) are fully tensioned.

The other item that you should check for tightness is the propeller nut or bolts. This is especially important on Glow/Nitro powered planes where vibration may have resulted in a loosening. Not to say you shouldn’t also check the propeller fixing on Electric models also.

Control Surface Movement

Once you have switched on your radio transmitter and receiver, check that ALL control surfaces are operating correctly and freely.

Go through a sequence of stick movements and watch carefully that the control surfaces move in the correct sense. This is especially important for the Ailerons. You wouldn’t be the first pilot to waggle the aileron stick and observe the movement without recognising that they are reversed.Clevis security

Don’t forget to check the integrity of the throttle linkage connections. Give each control surface a gentle pull to ensure hinges have not come loose. Make sure you have brought with you the necessary glues and fixings to rectify any problems in these areas.

Check that the ‘snap links’ are properly closed on the control horn clevises and that the small fuel tubing keepers are slide home to prevent them opening in flight (see right).

Check that the servo output horn linkages are properly attached and that the horn retaining Servo extension saversscrew is properly screwed home so that the horn cannot turn on the spline.

In modern ARTF and other models it is quite common for servos to be located close to the control surfaces requiring extension leads to be fitted between the receiver and the servos. If you have this situation be sure to fit servo lead extension savers to prevent the leads parting company under tension (see right).

Battery Voltage & Capacity Checks

First of all you need to ensure that you have fully charged your transmitter battery, preferably overnight, to ensure it has full capacity ready for a busy flying session.

A word of caution here; many people replace the radio manufacturers supplied batteries with the new generation ‘slow discharge’ NiMH batteries or even LiPo or LiFe batteries that offer greater capacity than the generic types. It is very important to appreciate that these higher capacity batteries require either a higher current output charger or a dedicated Lipo/LiFe charger.

Understand that although your battery checker may indicate aBattery Capacity Tester full voltage reading, this does not necessarily mean that the battery is fully charged. You need to use a ‘Capacity Checker’. This will tell you just how much energy remains in the battery as a percentage of its full capacity rating.

The charger supplied by the manufacturer will normally be a slow charge variety for NiMHs. If you decide to use this charger for the new generation ‘slow discharge’ NiMHs you need to divide the maximum output current capability of the charger into the maximum capacity of the battery to determine the number of hours of charge required.

For example, if your charger is rated at 60mA output and your battery is rated at 2500mAH then the theoretical number of hours required to charge this battery from flat state will be 2500/60 = 41.7 hours.

Should you have a very new set of gear supplied with a LiPo/LiFe battery then the manufacturer should have supplied a dedicated charger for the purpose.

Glow/Nitro planes and Electric planes using an ESC (Electronic Speed Controller) without a BEC (Battery Eliminator Circuit) will require a dedicated receiver battery that, again, you should have checked and, if necessary, recharged overnight. Once again be sure to check the capacity of your battery and make sure you give it enough hours of charge if using a slow charger.

Electric planes often rely entirely on the power battery to supply the voltage to the receiver via a BEC. In this instance you only have to ensure you have fully charged your power battery.

Check Engine Reliability and Tuning

This only applies to those of you using Glow/Nitro engines or Petrol/Gas engines. There is nothing more frustrating than arriving for a day’s flying to find your power unit is refusing to start or run reliably. It is always best to set up your engine before a flying session confident that it will start and run reliably for you the very first flick of the propeller.

I see so many flyers spending an hour or two trying to set up a troublesome engine at the field when they could have eliminated the problems at home. Such problems are often attributable to faulty plumbing, failed glow plug, discharged glow ignition battery, poor engine seals and incorrect needle settings.

Prepare To Fly

Having covered all of the above checks you should have an aeroplane that is fit for purpose. Now you need to carry out a sequence of events that will eventually find you with model on the runway and you ready for Take Off.

With you plane suitably restrained and incapable of causing injury to any of your fellow flyers, fuel tank filled or power battery installed you are ready to start up the power plant.  Turn on your transmitter and, if using MHz frequencies, ensure your aerial is fully extended.  Then move the receiver switch to ON and start your engine (Fuel energised engines only of course!). Once running, check for reliable idling and smooth full throttle response.

Check that all of the controls are functioning properly under full power. If anything at all does not react as it should, DO NOT ATTEMPT TO FLY! Your plane is an accident waiting to happen.

With the transmitter switched on, Electric models should be energised by connecting the power battery to the ESC. Wait until you hear the correct recognition tone from the ESC/Motor combo. This will tell you that the ESC is correctly energised and that the supply to the receiver is working correctly.

Smoothly open the throttle and ensure that the motor speed increases to maximum and reduces to a stop in sympathy with the throttle stick movement.

Again, be sure to check all control functions are operating in the correct orientation. I repeat, if anything at all fails to react as it should, DO NOT ATTEMPT TO FLY!

Prepare To launch Skyward

Before taxiing or carrying your plane to the take off point, check the direction of the wind if any. Check the club windsock or tie a piece of ribbon or thread to your transmitter aerial as a wind indicator. This is important as you need to take off into wind so that your plane achieves flying speed more quickly, responds correctly to airflow over the flying surfaces and gets airborne safely.

As the thrust of this website and associated posts are aimed at getting newcomers flying safely I propose to concentrate on trainer type planes. These generally take off from the ground so I will discuss this method of taking off here.

Hand launching is usually applicable to park flyers, smaller planes and those without an undercarriage. I will look at this method of getting airborne in a later post.

Position your plane on the runway nose into wind and prepare for take off. Take a good look all around you and assess the field status. Make sure that there is no-one or nothing that your plane could possible collide with during the take off phase of you flight.

Slowly advance the throttle and, especially if you are flying a Glow/Nitro powered model, be prepared to feed in a little left rudder to counteract the tendency for engine torque to cause a swing to the right.

Continue to increase the throttle to increase the speed of your model. Trainers are designed to have natural lift at high throttle settings so the nose should start to rise as the speed increases. as the nose starts to rise apply the smallest amount of up elevator to encourage the plane to lift off.

Hold the elevator steady and watch the plane climb. If it starts to drop a wing either right or left, use the ailerons to bring them back to the horizontal. If the nose starts to wander off the straight path, use a tiny bit of rudder in the opposite sense to swing the nose back on track.

At no time during this phase should you take your eyes off the plane. Once the model has attained a reasonable altitude of around 40 to 50ft (10 – 15M) commence a turn AWAY FROM THE FLIGHTLINE. This is most important as turning the other way will cause you to overfly the pits area where vulnerable people will be present.

Commence by moving the aileron stick gently in the direction of the turn you want to make. When you see the wings start to respond to this control input, pull back very slightly on the elevator stick to make the plane turn round the corner.

When the model is flying in the direction you want it to, release the aileron input and the elevator input. Because most trainers have self neutralising attributes due to the the wing dihedral, it should settle back into straight and level flight. If it doesn’t do this naturally just apply a little opposite aileron to level the wings horizontally.

Staying Aloft

Having successfully reached a safe flying altitude your previous flight training should be adequate for you to complete several circuits. If this is not the case then I would suggest you shouldn’t be considering a take off on your own.

You need to have practiced maintaining circuits at constant altitude before you even consider either taking off or landing your model. Take offs and landings are much more difficult than flying simple circuits so perfect them before attempting these more difficult tasks.

Flying rc planes safely and competently involves a sequence of events that need to be learned over a period of time if you are to keep your plane in one piece. The old adage “Learn to walk before you learn to run” is very relevant here.

Moving On

I hope the last two posts have helped some of you progress with your flight training. If so, you may find my book “Flying Radio Controlled Model Aircraft “ useful. It will take you through a full programme of instruction on how to fly an rc model plane.

Read the feedback on my website page covering “Research” from those who have used this book to help them in flying rc planes successfully.

If I can help anyone personally please feel free to ask your questions through the ‘comment’ facility at the bottom of this post or on any of my previous posts or web pages at www.rookiercflyer.com.

Colin

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 



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Posted February 19, 2016 by Colin Bedson in category "Essentials", "General Flight Training

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