The battery is removed once the engine is running steadily. Some plugs are now designed without idle bars, to avoid any risk of the bar falling off and into the engine's cylinder. Laydown engines boost the realism of the model and help lower its center of gravity to hold to the track better. A device attached to the exhaust stack of the engine to reduce noise and increase back pressure, which helps low-speed performance. This plate can be removed to increase power, but only if there are no noise restrictions where you fly.
Some carburetors have separate needle adjustments for low and high throttle.
These letters stand for Rear Exhaust, in which the muffler is positioned behind the engine. Such a setup decreases drag in airplanes, and may also be necessary with certain car chassis layouts. An engine with a remote needle valve increases the pilot's safety by enabling him or her to make adjustments well out of the way of the spinning propeller. ABC is one example of such an engine. These letters stand for Side Exhaust, in which the muffler is positioned to the side of the engine.