I just want to know what thicknesses of biofoam should i use for building different planes, i mean like what thickness is the best for small indoor planes, outdoor planes , large size outdoor planes, etc? I am planning to build a blue-baby or a similar trainer plane so can i use a 5mm biofoam sheet. I am thinking about buying the pack of 10 5mm biofoam sheets. And yes thanks so much in advance for your valuable suggestions.

Anyone having suggestions??

For planes with almost 1  metre wingspan parkfliers you can use 5mm depron with 3mm carbonfibre.
For lighter planes indoor, its better to use 3mm depron.
9mm depron is mostly used for fusulage of parkfliers. You can use 5mm depron also reinforced with carbonfibre

Thanks so much foamybuilder.