They are very quiet and the copter flies very smooth with it, but the reaction time is not as snappy as with 2-blade props. Nevertheless flips and rolls are possible with it.
Better test: https://www.youtube.com/watch?v=sK8S24kfYYg
Bought here: http://cgi.ebay.de/282043948973
...
https://www.youtube.com/watch?v=t5ukrMmeoW4
Got this kit from https://www.tindie.com/products/deshipu/game-10-game-console-kit/ After some problems with compiling the game which Deshipu helped me to solve, I could install and play vacuum invaders. Nice hardware.
...
https://www.youtube.com/watch?v=eI_h6s1htdA
Just finished my project, see http://www.frank-buss.de/4004/index.html for details.
Music: "I make you a Spaceman" by Kevin Bryce: http://freemusicarchive.org/music/Kevin_Bryce/Disrememberance/Kevin_Bryce_-_Disrememberance_-_08_I_make_you_a_Spaceman
...
https://www.youtube.com/watch?v=K9xvX62NGG8
I'm learning how to fly in acro-mode with my ZMR250. In the end I drifted to the right and overdrove, so I crashed into the left tree. The copter is still flying, but the display of my Sony cam doesn't look too good now, but it is still working and I can control it from the remote app from my iPhone, no problem :-)
music: Rolling by BoxCat Games
http://freemusicarchive.org/music/boxcat_games/nameless_the_hackers_rpg_soundtrack/boxcat_games_-_nameless-_the_hackers_rpg_soundtrack_-_13_rolling
...
https://www.youtube.com/watch?v=5KkSf67hHqM
model: dragonfly
power supply: a few mosquitoes per day
special features: very quiet and agile, comes in different shiny colors
flight time: hours without pause, depending on the number of mosquitoes
work in progress: remote control and FPV by soul-transfer
...
https://www.youtube.com/watch?v=qCiYQEt3N0U