Spaceclam
Posts: 4640
Joined: 4/13/2003
From: chatsworth,
CA, USA
Status: offline
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i got the idea for four rotors from the draganflyer becuase i figured it would be most stable that way. however, it was originally a school prodject so i figured that i coudln't go wrong that way. i use 4 gws eps300c-c motor system that i have installed ALL capacitors on (you will get a lot of radio glitches if you do not) swinging 4 10x4.5 props, two clockwise and two counter clockwise from www.toddsmodels.com i use a hitec feather for a reciever, 4 hitec 1010 speed controls (they are now discontinued. if you want to attempt this, you need to get one with a bec switch so you can turn only one bec on at a time. a motor arming switch is prefferable too) there are two gws microgyros on there. the problem with them is they are accurate within themselves, but you have to reset the zero point every time you turn them on. currently, i have all the mixes dome in my radio and do not have yaw control. however, i am soon going to go to vtail mixers (i did originally but those wattage mixers are so innacurate it woudln't work) to allow me to have yaw control. the setup is as follows. you hay want to draw this out to help it make sense.
you have 3 mixers, that i will label #1, #2, and #3 and a four channel reciever.
plug the slave of mixer 1 into channel 1
plug the slave of mixer 2 into channel 2
plug the slave of mixer 3 into channel 4
plug the master of mixer 3 into channel 3
plug the master of mixer 1 into one of the outputs of mixer 2
plug the master of mixer 2 into the remaining output of mixer 3.
that will give you pitch, yaw, and roll control. the outputs mixer 1 will control a set of two motors located at opposite ends of the craft. likewise, mixer 2 will opperate the other two in the same fasion.
each set has the props rotating in the opposite direction of the other set. so, rudder would increase the speed of one set and decrease the other, causing the torque to turn the model. all this would have worked, but because i had the master of one innacurate vtail mixer plugged into the output of another innacurate vtail mixer, control was unachievable.
as for stablilty, i would lower the box down more, except i have it designed so that the battery which is configured in a hump position provides the majority of the strength.i used the battery as a center structure to keep the top seperated yet firmly attatched to the bottom plate, while i have pretty makeshift supports along the sides. this has made for one tough design, and i would hate to change it. flight is controllable however. for anybody who has flown an rc helicopter, it is like having an overweight helicopter with a big engine in it. pitch and roll control are responsive, but it is slow to change direction. it is the same way with this, however it is still controllable. the picture is decieving. the battery (a 10 oz high discharde nicad) puts the cg about 1.5 inches below the rotor disks. however, the day after i posted that one of my motor leads came undonein a controlled hover and it instantly flipped over and broke one of the gearbox housings so i am out of comission for a little while. i also installed a rollcage, give nthe fact the thing landed upside down. i will also be ordering the vtails probably within the next week. i will keep you posted. i only get abotu 2 mins of flight time because i am drawing probably at least 30 amps. that is the best estimate i have. at full throttle it will draw almost 8 amps, but i fly at 3/4 throttle. it's been a fun prodject certainly. i will keep you posted. danvel, if you are seriously interrested in making one of these things, they are really fun. i will try and get a flying picture when i get it all together.
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