Differences between Ni-Mh and Li-Po batteries
Nominal voltage is 1.2v per cell for NiMh, and 3.7v per cell for LiPo. NiMh come in standard size round hard cases, and are very difficult to physically damage; LiPo come in various sizes -- usually rectangular shape -- soft packaging which is easily damaged in a crash. If damaged, or overcharged, or over-discharged, or too much current drawn from them, LiPos may catch fire. Even if they don't, they should be discarded if there's any sign of significant physical damage. Weight is the biggest reason for using LiPos. They're about 1/3 the weight of similar voltage and capacity NiMh packs.
Difference between a Heli and Quad copter
Kit Car vs RTR
What is RTR/RTF, ARTR/ARTF, BNF, PNP, Kit
RTF - Ready To Fly - includes an assembled aircraft and everything you need to get into the air, including transmitter. BNF - Bind N Fly - includes the assembled aircraft, which means (where applicable) the servos, receiver, motor, speed control, and gyro are already installed. Also includes a flight battery and charger. BNF is a Horizon Hobby trademark. BNF Basic - a new completion level that started with ultra-micro products. Takes away the flight battery & charger from BNF. PNP - Plug N Play - takes away the receiver from BNF Basic. Customer must provide the receiver, flight battery, charger, and transmitter. PNP is a Horizon trademark, RxR is the same level, but the Hobbico name. ARF - Almost Ready to Fly - usually contains an assembled aircraft but no electronics. Customer supplies and installs servos, motor, speed control, gyro, receiver, and supplies his or her own battery, charger, and transmitter. Kit - Just like the ARF, but the aircraft is not assembled.
Differences between Enamel and Acrylic Paint (and lacquer)
Tanked and Tankless compressors
Glues! Plastic, ABS, super (foamsafe), Epoxy. entire UHU range
MOST kits dont come with paint, what is a 'sprue', how do I get parts off the sprue