SLOPING OFF...
...the Newsletter of Christchurch and District Model Flying Club for...March 2025
RTP
A brief explanation of the Round-The-Pole flying
By David Bicker
RTP, or Round-The-Pole flying has been around since the early 1960’s with little change over the years in how it is done. It was a way of enjoying flight pre-RC remote control days. An alternative to the limitations of free flight – especially when indoors. (See also the RTP Sloping Off from a couple of years ago - Ed)
A good selection of the models flown at the demo, belonging to Trevor (most realistic flight with the autogyro - see it on the video link below), Brian, Alex and Roger
And the awestruck spectators
The basic set-up is a vertically mounted pole weighted by a heavy base plate. The pole itself can be made from an insulated material so that the contact points for the flying / power lines to the model can be mounted on the same pole, but separated electrically. Alternatively, a metal pole can be used with insulating sleeves between it and the bearings that are used as the moving connection points on the pole. 2 bearings for +ve and –ve connections to the model’s motor.
Frank’s canard got the biggest cheer of the night when it finally flew - his Carioni failed but what a lovely model!
Both were given Toroidal propellors - the first worked, the second might have done but for some glue on the prop shaft!
The flight’s speed and height depend on the trim of the model, plus the motor speed controlled with a speed controller knob on a small box that is linked by wires to the flight pole.
Models are attached to the flight / power wires by a stiff wire mounting that projects out of the side of the fuselage from below the wing that faces the pole. In the original design, there is no remote control of control surfaces. These can all be set before flight. If the flight rotation is anti-clockwise then the rudder is trimmed to the right to compensate for centrifugal force trying to swing the tail outwards away from the pole during flight. The elevator can be manually trimmed to attain a level flight attitude.
Ambitious flight of the evening was Alex’s glider, towed by the SE5. Unfortuately centrifugal force took the glider to the walls and lack of restraint flipped it upside down
When researching this hobby, I found a more complex alternative system can be used to have more control of the model in flight and to achieve gentler, more scale-looking landings.
“Flying” can be quite confortable...
This method adds an RC controlled servo mounted on the side of one of the 2 pole mounted bearing, with 2 control wires attached to it. These trail out to the model alongside the power lines and are linked to a mechanism that controls movement of the elevator. This system allows for more controlled flights and landings and some more aerobatic flying. But I wonder what sort of a mess of wires you would end up with if 2 or 3 models in flight around the pole got tangled up!
I have posted a YouTube video of the entertaining evening that we had at Bransgore VH on Feb 5th 2025.
Many thanks to Ruth and Trevor Hewson and Peter Chaldecott for laying on the evening demo - and it may happen again at one of our Workshop days, if the hall at the Church is big enough.