The last one I built was far too big for use on mobile devices and I took it down. Recently I've felt the urge to make a new one but in a smaller design. This one hasn't got a lot of fuel so for extended flight time use only the twin engine (Activation group 1). For more acrobatic abilities turn on the VTOL engine (Activation group 2). This has pitch and roll controlling VTOL nozzles so in theory can be stationed in an indefinite mid-air floating position with ease subject to ho ow long the fuel lasts. I find about 35% thrust with all engines is enough for this. For an interesting vertical take off, use all engines and pull up hard on the pitch and watch the back end drift out. Also lands easily on the carrier and glides at 100mph without a problem. Rate, comment and enjoy!