Hello
I am working on fabricating an ornithopter. Can any1 help me regarding the the fabrication of gear box and calculating the optimum gear ratio...
Any specific dealer or club in India which can help with the parts??
Hello Nashim,
1) The gear ratio would depend upon the KV rating (RPM/volt) of the motor you use AND the frequency of flapping you want.
eg- A 2000 KV motor running off a 7.4V battery would give you an rpm of 14800 which with a gear reduction of 25 gives 592 rpm equivalent to a frequency of ~10Hz another combination would be a 1300KV motor running off an 11.1V battery giving an rpm of 14430 with a gear reduction of 25 gives 577.2rpm which is equivalent to ~10Hz.(N/60= frequency)
2) The higher the motor KV rating or the higher the voltage of the battery the more gear reduction you will have to use.
3)The higher the gear reduction the more gears are required, the more the weight.
4)The higher the flapping frequency the more stresses are generated.Ideal range (4-6Hz).
5)The less the gear stages the better as friction and complexity is lower.
For more info please refer to
http://www.ornithopter.org/how.gear.shtml (http://www.ornithopter.org/how.gear.shtml)
http://homepage2.nifty.com/smark/HabatakE.htm (http://homepage2.nifty.com/smark/HabatakE.htm)
5) Custom made gears are hard to find in India, you will have to make do with the gears you can get from printers and xerox machines or use those available online have them laser cut or 3d printed.
some useful websites-
https://www.ponoko.com/ (https://www.ponoko.com/)
http://www.3dprintronics.com/3d-printing-services (http://www.3dprintronics.com/3d-printing-services)
http://www.hobbyking.com/hobbyking/store/__423__59__Electric_Motors-Gearboxes_Parts.html (http://www.hobbyking.com/hobbyking/store/__423__59__Electric_Motors-Gearboxes_Parts.html)
additionally refer to these threads in RCIndia forum.
http://www.rcindia.org/self-designed-diy-and-college-projects/my-ornithopter/ (http://www.rcindia.org/self-designed-diy-and-college-projects/my-ornithopter/)
http://www.rcindia.org/self-designed-diy-and-college-projects/scratch-built-ornithopter-for-5th-anniversary-sweepstakes/ (http://www.rcindia.org/self-designed-diy-and-college-projects/scratch-built-ornithopter-for-5th-anniversary-sweepstakes/)
http://www.rcindia.org/kites-trains-free-flight-and-all-others/mini-rc-ornithopter-maiden-flight/ (http://www.rcindia.org/kites-trains-free-flight-and-all-others/mini-rc-ornithopter-maiden-flight/)
Hope This helps,good luck.