RC gliders ( sailplanes )
- a gentle intro to radio control flying
RC gliders, also known as sailplanes, can offer the beginner a very gentle introduction to the radio control flying hobby but can also offer the experienced rc pilot some truly exhilarating aerobatic and racing opportunities, such is the diversity of radio control gliding.
The majority of beginner rc gliders are 2 or 3 channel, with control to either rudder and elevator or rudder, aileron and elevator. This latter setup is my preferred choice as it obviously makes the glider far more maneuverable with better flight characteristics.
The more advanced rc gliders and larger sailplanes can have more channels still, with additional controls for flaps or spoilers, air brakes and even tow line release hooks in the nose and retractable nose wheel.
But simpler rc gliders like the classic Goldberg Gentle Lady
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Flying rc gliders of this type can be a very peaceful and relaxing experience. Typically flying speeds of such gliders and larger sailplanes are much slower than the speeds of powered airplanes and their stability gives the pilot plenty of time to react. Gliders like the Gentle Lady are very forgiving in the air and won't punish you for making mistakes with your Tx sticks!
Of course, different types of glider have different flight characteristics and at the other end of the scale the sleek racing gliders can be thrown around the slopes at crazy speeds in strong winds. And while on the subject of speed, did you know that the fastest radio control aircraft in the world is a glider?! Not a jet but an rc glider! Yep, the current world record (as at 2012) is getting close to 500 m.p.h in the sector of dynamic soaring. So you can see that radio control gliders offer more than you might think!
A huge advantage that rc gliders have over powered radio control aircraft is that of flight time; if the conditions are favourable with good lift during a rc slope soaring or thermal flying session then you can keep your glider aloft all day. No need to land for refueling or replacing a motor battery pack.
RTF vs. ARF RC gliders
Unfortunately there are very few Ready To Fly rc gliders available (if any?) and this is a shame for beginners who just want to get flying. It seems that the only RTF gliders around are of the powered variety. Presumably this is a reflection on market demand, and in my opinion it's a shame that at least some manufacturers aren't offering a decent RTF 2 or 3 channel glider for sale.
An Almost Ready To Fly glider is the next best option but obviously you're going to have to buy, install and set up the radio gear yourself. A certain degree of aeromodelling knowledge is required to complete and set up an ARF rc aircraft, but if you're completely new to the hobby there is plenty of help around.
For intermediate modellers, the Seagull range of scale gliders is a good one, and the quality of Seagull aircraft is very good. Having had a couple of their aircraft, I can vouch for their quality.
Above: Seagull make some good scale ARF rc gliders, this Ka8-B being one of them.
Types of RC gliders and sailplanes
There are several different categories of radio control glider, as well as a large diversity of model designs ranging from general sport gliders to expensive carbon racing ones to large scale vintage sailplanes. Below are some examples of and brief introductions to the more popular types...
General sport gliders
These come in a large variety of shapes and sizes and are suited to flat field flying with assisted launch or the very popular sector of slope soaring.
Typically three channel (rudder, aileron & elevator), sport gliders can handle a variety of conditions and are, usually, aerobatically capable. Sport rc gliders can be non-scale or scale, although many scale gliders of this type are labelled as 'aerobatic' rather than 'sport'.
Construction, as with any rc aircraft, can be traditional balsa and ply or foam such as the popular Multiplex Cularis, shown below, or GRP (glass reinforced plastic aka fibreglass). This latter material is very common in rc glider construction.
Above: Multiplex have produced some nice foamie gliders, like this Cularis.
Hand launched gliders
A simple two channel example is the Great Planes Fling, shown right, although owner feedback about this particular glider hasn't been great. Gliders like this one can also be launched with a simple 'high-start' launching system so if your throws aren't quite strong enough then you can still get airborne. But with the right throwing technique and strength a hand launched glider can easily reach an adequate altitude without any external aids.
Once launched, either by a throw or catapult system, flight duration is achieved by using thermals and wind to keep the glider aloft.
Discus Launch Gliders (DLGs)
Following on from the standard hand launch gliders mentioned above, a Discus Launch Glider is a newer breed of rc glider that's become very popular with flat-field flyers.
A DLG has a specially designed wingtip handle (a strong pin running vertically through the wing) that is held with index and middle finger; the pilot spins in a 360 degree circle and launches the glider upwards on exiting the spin, just like a field athlete launches a discus (hence the name DLG...).
You don't need to be strong because the force needed to power the glider upwards is generated during your spin, and then the design of the glider aids the steep climb. With the right technique a Discus Launch Glider can reach a surprising height and once the glider has leveled out after its vertical climb, your thermal-seeking can commence.
The big advantage with a Discus Launch Glider, and indeed a normal hand launch glider, is that you don't need to be on a hilltop or in an area large enough to take a long bungee/Hi-Start system. A DLG can be launched from a relatively small space, as it goes vertically upwards.
Thermal soarers
RC sailplanes that are intended for thermal soaring tend to have larger wingspans, up to 4 meters for the serious competition models. Their construction is kept as lightweight as possible and they have a low wing loading, this combination keeps their glide rate (vertical descent) to an absolute minimum.
There's a definite skill to thermal soaring; if the pilot can't successfully locate the thermals then the glider won't stay airborne for any great length of time. That said, a thermal soarer will out fly a sport glider (time aloft) under the same conditions, simply because of the better glide rate.
A fairly typical dedicated thermal soarer is shown below:
Combat RC gliders
A personal favourite of mine, 'combat' gliders are relatively new to the scene of radio control gliding and soaring.
Combat gliders are generally much smaller than traditional soarers and are typically made from EPP (Expanded Polypropylene), a foam-based material that's incredibly tough and resilient to damage, making the gliders more or less indestructible. The tail feathers can be sheet balsa or, more commonly, fluted polypropylene sheet (eg 'Corflute'), another very bendy and crash-resistant material.
EPP combat gliders are commonly covered in reinforced tape to add strength, and then coloured tape to finish - all this tape also adds to the durability. Other ways of finishing them include paint and low-heat iron on covering film.
The idea with combat gliding is to fly as a group and try to knock your opponent's glider out of the air - because the EPP rarely gets damaged, it's quite safe to fly straight into another glider at full speed!
My EPP combat glider is shown below, an 'Eraser' from Canterbury Sailplanes of New Zealand:
Combat gliders are a great deal of fun, but even if you can't get a group together flying one on your own is equally exhilarating. Because of their general design they can be very maneuverable indeed and in the right conditions can be flown fast and aerobatically. Highly recommended for some slope flying fun.
Well those are just several of the basic categories of rc gliders and sailplanes; as has already been mentioned radio control gliders have many many types, shapes and sizes from traditional built-up kits meant for relaxed soaring to modern carbon fiber racing machines capable of incredible speeds and performance.
Whichever type of rc glider you choose, you'll be entering a hugely popular sector of the radio control flying hobby. The ease of control and gentle flying characteristics of many gliders make them a great attraction and introduction to the hobby, and I can highly recommend giving rc gliding a try especially if you live near an open slope that faces the prevailing wind!
Mini RC gliders
A bit like RTF rc gliders, mini gliders are hard to come by. Only recently (late 2012) have E-flite produced their UMX ASK-21 glider, an 860mm wingspan foam/carbon reinforced scale sailplane.
This looks like a great mini glider, and hats off to E-flite for being the first to manufacture such a model. I wouldn't mind putting one on my Christmas list! Given how many mini and micro rc aircraft have appeared in the shops in recent years, perhaps we can expect to see more gliders this size in the future.
Electric Powered RC gliders
When is a glider not a glider?...
Another option is to purchase an electric powered glider. These are 'standard' rc gliders that have the added feature of an electric motor fitted with folding propeller blades. One very popular RTF example is ParkZone's foam Radian RTF, shown below...
Take one normal glider, add an electric motor and folding prop
and voilá - you have a powered rc glider!
Following a normal hand launch with power on, you can fly the powered glider up to a suitable height and then turn off the motor. With the motor stopped, the forward airspeed of the glider causes the wind over the nose to push back the blades of the propeller tight against the side of the fuselage, thus reducing drag.
If the glider is losing altitude you simply power up the motor - the prop blades flick out to their normal positions and you climb away again to regain height.
Electric powered rc gliders can also be flown under 'competition rules' whereby the motor can only be used once per flight and run for a set amount of time (say 30 seconds). This means that the pilot can launch the glider under full power and fly it as high as he can get it in that time, before switching off the motor and relying on his soaring skills to stay aloft.
Electric powered gliders may be a 'cheat' to the purists, but they're still gliders in my books and I do indeed have a couple in my collection (a Radian Pro and a JP Pretty 1500).
The obvious advantage that an electric powered glider has over a normal rc glider is that you don't need to find a hilltop or cliff, or a large enough space to operate a bungee system; powered gliders can be launched from flat ground and in spaces that may be too small for a bungee.
Powered rc gliders like the Radian RTF are a great way to experience some gentle, relaxing rc flight and of course they offer the best of both worlds - the availability of power and the tranquility of rc gliding! Read more about rc powered gliders.
Whether powered or unpowered, radio control gliding is a hugely popular sector of the rc flying hobby with its dedicated followers be they slope soarers or flat field flyers. Perfect for the beginner and advanced rc pilot alike, gliders and sailplanes will give you a truly rewarding experience.
From a personal point of view, rc gliders are my favourite form of radio control flight. They require very few accessories and there are no noise issues to worry about. In fact, the only real concern is whether or not your radio gear batteries will last as long as you want to fly for!
The challenge of having to seek out lift and use the air to keep your glider aloft, rather than just rely on motor power and thrust, is an addictive and exhilarating one. Why not give it a go?!
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