Convert the Guillow Lancer to RC Flight

Front view of completed Guillow Lancer

Front view of completed Guillow Lancer

One of the enjoyable aspects of flying model aircraft is taking an existing free flight design, whether from a kit or plan and converting it to radio control flight.

There are literally hundreds of original and interesting free flight model aircraft designs that have been produced over the years. Due to the large size and heavy weight of radio control electronics in the past, most of these aircraft could not realistically be converted to indoor flight.

Today, due to the widespread availability of affordable micro-electronics and miniature electric power systems, a wide range of aircraft can be successfully converted to RC flight.

Guillow Kits

Guillow’s model aircraft kits have been a mainstay of modelers for years. The majority of Guillow kits are planned for rubber powered free flight. Overview directions are often included for a gas motor conversion for U-control or single channel RC flight.

The Guillow Lancer seemed like an ideal candidate, due to its optimized free flight layout, for an adaptation to radio control guidance. As this would be my first attempt at a Guillow RC conversion I wanted to increase the odds towards success. The Lancer looked to be a great choice.

Tail view of the Lancer's rudder and elevator

Tail view of the Lancer’s rudder and elevator

The Lancer is not a scale model, thus the designer optimized nose and tail moments for stable flight. The wing has a polyhedral layout that aids my plan for three channel control. The overall size, with a 24 inch wingspan, seemed like it would come in under a three ounce total weight. This is about the maximum for the electric motor I planned to install.

Lancer nose section under construction

Lancer nose section under construction

Radio control electronics and motor are key ingredients for a successful conversion. I use the ParkZone control “brick” for models of this size. ParkZone products are offered by Horizon Hobby and other vendors.

The brick is an amazing piece of hardware that contains an electronic speed control, two linear servos and receiver. It is mated to the electric motor and a compact 160 milliamp lipo battery. I have used this control system with a range of other models to include the Fokker Spin.

When working a conversion of any free flight design to RC flying a good first step is to locate the optimal places to install the motor and electronics. You need to keep in mind considerations such as electric wire lengths for the battery and motor connector to the brick.

Kit box image of the Guillow Lancer model aircraft

Kit box image of the Guillow Lancer model aircraft

Equipment Location

The most important concern is to place these items where they will have minimal impact on the center of gravity. By planning ahead you can prevent the need to install nose or tail weight on the finished model to get the aircraft properly balanced at the center of gravity.

The other design element before construction starts is an overview of the model’s basic structure to see where components of the fuselage, tail surfaces or wing need to be strengthened.

For example, a typical free flight model has a relatively weak nose area as it needs to support a rubber band powered nose/prop block. This area will need to be beefed up to hold the electric motor securely in place.

Gordon holding Guillow's Lancer model airplane

Gordon holding Guillow’s Lancer model airplane

The landing gear attachment points will be sized up to handle ground takeoffs. Some sort of tray needs to be envisioned for the RC electronics. By taking a moment to think these processes out before cutting balsa wood you can save yourself a lot of time and more importantly get the changes installed correctly the first time.

The Lancer’s long nose moment is a good discussion point. Typically an airplane’s nose is shorter than desired and the finished model comes out tail heavy. The Lancer offers the opposite situation as the nose moment (distance from the center of gravity to the nose) is longer than normal. If the control electronics are located too far forward in this case you could end up with a nose heavy balance point. By thinking ahead regarding internal component location you can save the need to add tail weight.

Underside view of the Lancer showing landing gear and electronic installation

Underside view of the Lancer showing landing gear and electronic installation

The Lancer’s light weight wing structure is not robust. This is a suitable approach to optimize a free flight design, but not for a radio control conversion. I decided to add some balsa structure to the wing’s center section where rubber bands hold the wing in place. I also knew from experience that the iron on covering adds a considerable amount of strength to the completed wing, thus saving the need for excess structure.

Two other matters needed to be addressed. The first was the narrow width of the fuselage. The fuselage dimensions are fine for rubber power but did not offer enough space for the electronic controls. The solution was simple: mount the brick sideways along a fuselage side.

The other change in construction comprised the addition of elevators and rudder. I estimated the size of these two control surfaces and prepared the plan for the construction and covering of these moveable surfaces. This included the need for hinging and control horns.

The video shows further construction details. The finished Lancer weighed it at two ounces, ideal for the motor used. Control throws were completely adequate for smooth flight in our Field House indoor flying location.

Lesson Learned

Initial placement of the motor and RC electronics in the Guillow Lancer

Initial placement of the motor and RC electronics in the Guillow Lancer

One learning point is the amount of lateral stability offered by the wing’s polyhedral. I quickly discovered that too much rudder input resulted in a spiral turn. This was compensated for by gently “blipping” the rudder to induce a turn.

I was very happy with the outcome of this conversion of the Guillow Lancer to radio control flight. The knowledge gained on construction techniques, equipment installation and test flights ensure that the conversions of other Guillow kits can be a success. Plus, you will have an airplane a bit different and more interesting that the other ready to fly models.

More model aircraft kit and plan conversions to follow!



Author: Gordon McKay