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|Do you know where all the obstacles are? (click small images to enlarge).||Pilots of full size aircraft always use check lists (click small images to enlarge).|
1. Range check
Some modelers incorrectly assume that because they are using 2.4 GHz equipment, that the radio link is more or less bulletproof. Although it is true that the link is generally more robust than lower frequency systems which use long aerials, there is more reliance on the the relative orientation of the transmitter and receiver aerials with 2.4 GHz equipment. For this reason, it is sensible to carry out a range check before flying, especially if a model's equipment has been altered in any way.
2. Have a plan for the flight
It is always wise to have a plan in your mind, certainly at least until the model gets up to altitude. Where are the obstacles at your flying field, and more importantly, what will you have to do to avoid them? What will you do if the motor stops just after take off? It's well worth reminding yourself before take off where the obstacles are, and where the suitable areas are if a dead stick landing becomes necessary.
3. Consider using a check list.
Pilots of full size aircraft know that using a check list is an essential part of getting safely airborne. This not because they lack skill or experience - it's just because they know that even the most experienced pilot could otherwise forget a simple, but important item.
Pilots of models can also benefit from the same approach. A check list doesn't have to be long or complex. A possible pre take off check list looks like this:
Can you think of any other items which would be good to include? Check lists are an especially good idea if you are inexperienced at flying, or if your model is complex - or even if you are just forgetful!
|Take off directly into wind.||Throttle up with care.|
4. Take off directly into wind
Birds always take off directly into wind. This reduces their ground speed, making take off easier and safer. Models also benefit from taking off directly into wind. Crosswind take offs are usually possible, but they can make life more difficult for the pilot, especially for those with challenging ground handling such as early biplanes.
5. Throttle up carefully
If the throttle is rapidly moved to full power, its quite easy for the model to become directionally unstable. This applies especially with taildraggers. It's much better to throttle up a little more carefully, adding power as the model gains speed and the fin and rudder start to make a greater contribution to directional stability. This technique alone can make all the difference between a model that is hard to keep in a straight line, and one that's relatively easy to get airborne.
6. Be willing to abandon the take off
It's always worth being willing to abandon a take off if its not going well. However, I've lost count of the number of models I've seen that whose pilots continued with a take off when they were not really in control of the model. Sometimes the model gets airborne, but this type of take off always runs a significant risk of the model suffering damage. If the model's behaviour becomes erratic during the take off run, just close the throttle and bring the model to a stop. This is much safer for the model and of course any nearby trees! Have a think about what went wrong, and then have another go.
7. Rotate gently
A model which is low and slow is at its most vulnerable, and this is exactly the situation the model is in on take off. If you are too enthusiastic with the application of up elevator, it is easy to stall the wing, with potentially disastrous consequences.
A low altitude stall must be avoided at all costs, but you should be able to prevent this by making sure you apply up elevator gently and carefully. This precaution applies to all models, especially those with sharply tapered wings, or those with small radius leading edges.
|It's important to rotate gently on take off.||If a multi motor model becomes uncontrollable, it's a great idea to immediately close the throttle.|
8. Multi motor models
If you are flying a conventional multi-motor model, if one motor stops in flight, the model can become uncontrollable extremely quickly because of the asymmetric thrust. For this reason, when flying a multi-motor model, it's a great idea to make the decision before take off that if the model goes out of control, the immediate response will be to close the throttle. This will eliminate the asymmetric thrust state, and give you a chance to get the model back under control - a deadstick landing under control is a far better proposition than a model spiraling in.
9. Hand launching
Many models have suffered crashes due to poor hand launches. Make sure your launcher knows how to give a good launch and has some experience. The basic idea is to launch the model so that as it leaves the launcher's hand, it is in level flight and at flying speed. Some more heavily loaded models will require a head wind to get airborne safely, while lightly loaded models can be safely launched in still air. Common hand launching faults are to throw the model upwards, or with insufficient speed.
|This electric RC Tigercat gets safely away from a perfect hand launch.||This small, fast model needs a bungee launch to get safely airborne.|
10. Bungee launching
Bungee launching is a great way to get fast models safely airborne. It is a very common technique for EDF jets, which need to fly fast. It is especially important when bungee launching to launch directly into wind. A wind sock can assist with assessing the wind's direction. A simpler and cheaper alternative is a 'tell tale' length of wool attached to a pole. When long transmitter aerials were common, the end of the aerial was a convenient place to attach this. These days, an inexpensive alternative would be a bamboo gardening pole.
I hope you enjoyed this article, and
that it will help you improve your take offs!
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