Launching RC gliders
- ways to get airborne
Launching rc gliders that are of the non-powered variety can be done in a few different ways, all of which are fairly easy to understand. Some are easier to do than others though.
This page will give you a brief insight into how it's done, by giving an explanation of the principle methods of rc glider launch. Most of the following methods can be done alone, but two of them require help from a fellow flyer.
The methods are:
A hand launch is the way that most rc gliders are launched when slope soaring from a hillside or cliff top, but hand launching rc gliders can also be done from flat flying sites.
When launching from a slope, you need to point the glider into wind, (which, incidentally, needs to be blowing up the slope towards you!) when you launch, so that the glider will catch the wind that's blowing up the slope face, and stay aloft.
When hand launching your rc glider, it's very important to give it a firm push, from about head-height. This is to get the glider moving at a reasonable speed as it leaves your hand, so it won't stall and fall out of the sky. The animation to the right shows a good, definite launch.
Another important point to note is that you should make sure that the glider is horizontal as you launch it. If you launch the glider with its nose pointing upwards there's a very good chance that it may stall and crash if the launch speed isn't fast enough. Or if the wind is strong, the glider can get lifted directly upwards out of your hand and taken backwards, completely out of control.
Angling the glider downwards slightly is acceptable but, again, if the wind is strong there's a chance that the glider will just get pushed into the ground by the wind, as it leaves your hand.
Once the glider is safely away from your hand and airborne, get your launching hand back onto the Tx sticks right away - your flight has begun! Of course, which sticks you use will depend on which mode your transmitter is. Personally I fly Mode 1, and launch with my left hand; that means I only have aileron control as I launch, and I can't use elevator until after I've launched.
If you fly Mode 2 and launch with your left hand, you have control over aileron and elevator at the time of launch - far safer!
Incidentally, it is quite possible (and sometimes necessary) to launch larger gliders with both hands, and have the transmitter dangling on a neckstrap. Lone rc glider flyers with large models often have to do this.
Hand launching can also be done from flat ground, if you're thermal soaring. The difference here is that you need to throw the glider at a definite upward angle, as hard as you possibly can, while trying not to tear your arm muscles in the process! Not all gliders (or arms) are suitable for this, but it is a recognised method of getting the glider into the air.
RC gliders suitable for hand launching in this way are typically smaller (say up to 1500mm span) and commonly called 'chuckies'.
Discus Launched Gliders (DLGs) are a newer breed of rc glider, designed with a particular launch method in mind.
A short pin through one wingtip is held by the pilot, who then spins around 360 degrees before flinging the glider upwards - in the same way a discus is thrown in the athletic field event. The centrifugal force produced by the pre-launch spin is enough to launch the glider to a surprising height, and the design characteristics of DLGs are such that the aircraft naturally goes into a steep climb immediately after launch.
The good thing with this form of glider launching is that you don't have to be strong, because the power comes from the technique.
DLGs are perfect for thermal soaring on a flat field.
Above: Discus launching a DLG.
Bungee launching rc gliders is completely different and can either be done on a gentle hillside or level ground.
The bungee system, also called a high-start, is a long length of elastic cord extended further by an even longer length of non-stretch cord (anything up to 10x the length of elastic). The bungee is pegged into the ground at one end and attached to a hook on the bottom of the glider at the other end. A small parachute is attached to the glider end of the bungee.
To launch, the pilot attaches the line to the glider hook (a metal ring at the end of the line slides onto the hook) and walks backwards, so stretching the bungee. When a suitable stretch has been reached, the glider is released and the bungee then pulls the glider up to a good height, as the rubber retracts its stretch.
With a small pull back on the elevator stick at the top of its climb, the glider releases itself from the bungee and your flight commences. The bungee then falls back to earth, slowed by the parachute.
Like discus launching, bungee launches are perfect for thermal flying over a flat field, provided that you have the length to lay out, and stretch, the bungee.
Above: the principle of bungee launching an rc glider.
Not all bungee launches go to plan; sometimes the glider can 'ping' off the bungee just after leaving the pilot's hand.
Launching larger rc gliders by aerotow should only be attempted by intermediate or advanced rc flyers. The glider is towed up to altitude by a powered rc plane, and then the towline release hook in the nose of the glider is activated and the glider is released from the tow plane.
Aerotowing requires skill and constant communicating between both pilots, and obviously the plane needs to be powerful enough to tow the glider without struggling. This method of launch is best done with larger rc gliders.
Above: aerotowing a large scale rc glider.
Image property of rcaerotowing.com.
For smaller scale aerotowing, take a look at the UMX Carbon Cub SS and UMX ASK-21 glider combination. Both aircraft come from E-flite and it's testament to the radio control hobby that this has become available.
If you're in to the smaller rc planes and you've got some guys to fly with, this is a great way to try your hand at launching an rc glider by this method!
This is a similar method of launching rc gliders to a bungee launch, in that the glider is taken up by a long line. The difference is that the line is reeled in by a powerful winch, typically operated by a pedal switch at the pilot's feet.
Winch launching is easily done by a single pilot but, like a bungee, a good length of space is needed to lay out and set up the winch.
Once the desired altitude is reached, the pilot can put the glider into a steep dive, just for a second, and then pull up steeply to get the line off the tow hook. Or a more subtle approach can be used, as in a bungee launch.
Just like the Space Shuttle started off in its early days, rc gliders can also be launched from the back of a second radio control airplane. This takes a larger sized plane to do the job and an experienced pilot to do the launch flight.
Because of these requirements, launching an rc glider in this way is really only limited to operations within a model flying club and it's not a hugely popular way of doing it, other than a great novelty factor!
Choosing the correct method of launching rc gliders really comes down to a few factors; where you are flying, what sort of flying you want to do and what type of glider you have. All methods work well for their intended purpose and you might find that you simply prefer one method of launch over another.
As you've read, some methods of launching rc gliders require two pilots while other methods can be safely done alone. Whichever launch method you try, be safe and take care!