Preparation is a key element to success in any competition. In the interest of Scale Aerobatics, preparation takes two forms. First, a competitor must practice and better his or her skills in an effort to execute the perfect flight sequence. Second, he or she must ensure that the radio system, aircraft, and engine work flawlessly on all competition airplanes, and that all spare items have been packed before travelling to an event.
At the Nats it is common to see pilots who have two airplanes that are fully assembled and ready to use, and all for good reason! Such pilots want to ensure that if any problems occur when it is their turn to fly, they have spare systems that are ready.
In this month’s column, I want to explain a few practices that can help new and experienced pilots. I will explain aircraft preparation and which electronic components could fail at any time. I will also examine a few basic problems that can occur with the engine and exhaust system.
I will also discuss spare components, because when competition day comes, a pilot should only think about performing the sequence to the best of his or her abilities, not about the functionality of the aircraft! Without further delay, let’s begin!
The Right Connections
Aeromodelers often collect and use different types of batteries, switches, etc. Because technology changes each year, so does a modeler’s inventory. However, no matter what electronics are found within an airframe, it is important that common connectors and switches are used.
Receiver batteries should be compatible. I equip my Giant Scale aerobatic airplanes with 4,000 and 6,000 mAh LiPo batteries from Spektrum that come with EC3 connectors. The connectors are compatible with the Spektrum nine-channel PowerSafe receiver and the Spektrum VR6010 high-current voltage regulator.
Although these are great connectors, I have used Deans Ultra plugs for years. I don’t want to have one airplane that uses all EC3 connectors and another that uses Deans Ultra plugs. This would make the need for spares a nightmare!
For airplanes on which I am not using a voltage regulator, I have the battery leads long enough that they can be plugged directly into the receiver, if needed. I’ll reveal why.
In the past, I have had connectors fail because of vibration at soldered joints. This has happened roughly 10 minutes before a flight demonstration on an airplane that used high-voltage servos. Because I didn’t have enough time to replace the switch, (which is the component that failed), I plugged the battery directly into the receiver. The problem was temporarily solved!
Because common connectors are used between all airframes, you can bring a spare battery or a spare switch to the airfield and use them on the day of competition. Even if a pilot brings two airplanes to a competition, he or she may prefer one over the other, making it his or her primary aircraft of choice. By having two airframes that use the same electronics, you can simply remove a component from one aircraft and install it in the other airplane in minutes!
Transmitter Redundancy
Using a computer radio offers many advantages from a programming perspective, but it also offers the end user a way to store and back up his or her system. Today, many computer radios use SD cards to store and transfer information from one transmitter to another. Other radios use a trainer cord, utilizing each radio’s internal memory rather than an external memory source.
Radio manufacturers are realizing the need to transfer between different types of radios. For Spektrum radios, for example, pilots can transfer between the DX18 and the DX9. Both transmitters use an SD card that allows the user to copy models to another DX18 or DX9 or transfer models to another DX18 or DX9 transmitter. The only limitations between the two are a few features and the number of channels.
The Futaba T14SG can use the model data of a Futaba T8FGS with an SD card, but the T14SG data cannot be used by the T8SG.
No matter what type of memory transfer process is used, if one has two identical transmitters, ensure that both systems have the aircraft files for the competition airplane before competition day.
Engines
All gas-powered aircraft vibrate, which takes a toll on the airframe and all components, so spares are a must on competition day! These spare items can be as simple as a few cowling bolts that may vibrate loose during flight, but you should also bring a spare muffler for a single-cylinder gas-powered aircraft or two mufflers if you are using a twin-cylinder engine on your aircraft.
If you are using a canister exhaust system or something similar, you should bring spare headers and spare gaskets. You can’t predict when a muffler or a header may break, but bringing a spare will ensure that you can continue flying during the competition.
Most of today’s gasoline engines feature either a Walbro or Tillotson carburetor, and both have a pump with two needle valves and a third screw, which is an idle-stop adjustment. The pump has a rubber diaphragm that may need to be replaced.
Many companies offer a carburetor rebuilding kit, so before you notice a drastic change in engine performance, disassemble the carburetor, clean out each component with carburetor cleaner, return the “high” and “low” needles to the factory-recommended settings, and replace the diaphragms.
You should not overlook the engine’s spark plugs. Routinely remove the spark plug(s). Excessive carbon buildup can lead to poor engine performance.
Final Thoughts
Preparation can make the difference between completing a competition or not. In an ideal world, pilots could foresee the future and what problems they may face, or, they would be able to bring their entire workshop with them! However, this is far from a reality!
It is important to know which spare items you should bring to an event and how to best prepare for that competition. Every measure must be taken to ensure that the pilot is focused and that his or her aircraft is always for the next flight. After all, every flight counts during a competition!
Until next time, fly hard!
