Bmatt is corrects that it dosent matter the thickeners of aluminum. One thing that has not been touched on yet is internal interference. All the components within the airplane give off RF emissions. That includes servos, CDI, regulators and the RX it's self. An aluminum airframe can trap these emissions in and reflect them to different areas of the airplane. If anyone is familiar with Wavegiude it's the same principal. If a signal is going through the the fus front to back, the signal frequency could actually increase. This is all theory of course and as we all know in practice things can work out differently.