Launching RC gliders
- the principle methods
Launching rc gliders that are of the non-powered variety can be done in a few different ways, all of which are fairly straightforward.
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:
Hand launching
A hand launch is the way that most rc gliders are launched when slope flying from a hillside or cliff top.
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 and stay aloft.
When hand launching your rc glider, it's very important to give it a firm push, from just above 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 let go. 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.
Once the glider is airborne, get your launching hand back onto the tx sticks right away - your flight has begun!
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 recognized method of getting the glider into the air.
Discus launching
Discus Launched Gliders (DLGs) are a fairly new breed of rc glider, designed with a particular launch method in mind.
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.
Discus launching a DLG
Bungee launching
Bungee launching rc gliders is completely different and can either be done on a gentle hillside or level ground.
The bungee system 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 walks backwards with the glider in one hand and the transmitter in the other, 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.
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.
The principle of bungee launching an rc glider
Towline / aerotow
Towline launching requires either two people or a winch of some kind.
RC gliders that are launched this way are pulled up to a suitable launch height either by someone running along the ground towing the glider behind them on a long length of cord, rather like a kite, or the glider is pulled up on the cord by a fast-turning winch.
The principle is the same as for a bungee launch, in that the glider is towed to a good altitude before being released and commencing its flight.
An aerotow follows the same principle again but the glider is towed up behind a powered rc airplane, on a long length of cord. When a suitable altitude is reached, the cord is released from the nose of the glider and the flight begins.
Piggyback 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 model 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.
Related pages
Slope flying - tips for getting the most out of the slope.
Dynamic soaring - adrenalin packed slope action.
Thermal soaring - basic principles of flying on thermals.
RC gliders - an overview of gliders and powered gliders.
