Hello,
Recently found this forum after developing an interest in building a Multi-rotor DIY UAVs. I would like to ask a few questions.
I am interested in building an ArduPilotMega-brained Multi-copter (hexa or Octo) that can do the following:
1. Primary usage: using it in a UAV / Mission Planner configured autonomous mode
2. Carry a small video camera to record the flight during the mission. Not FPV, just onboard recording
and download to PC after mission completion is OK.
3. Flying time minimum of 30 minutes. I know this is a ballpark number, due to outside weather conditions vary actual times. So I am thinking still-air flying time.
Before I get all carried away do you think this is a realistic goal, especially the 30 minute flight time?
Would an Octocopter be a better platform to support longer flying times (because it can carry more battery oomph)?
It would be fun to eventually do the FPV thing, but not right away. Of course I realize heavier = lower flight times. I'm a Sport Pilot and fly a 2 seater weight shift trike (only skinny people in the back seat now).
After reading several posting I get some general perceptions that include:
Hexa can carry more weight than Quads (and Octos more than Hexas).
Hexa are 'safer' in that if a motor or two fail during flight it may not be a disaster, just panic and screaming :). Octos are more so.
A lot of discussions about Hexa seem to morph into the 'heavy lift' category where the goal is to carry a big camera for short time flights. I cannot say I've seen a lot of discussion about lengthening the flight times.
And then the Octocopter discussions go even further in this regard about heaving lifting (2 to 5 KG payloads). And Octo discussions seem to be in the flight time range of 9 to 15 mintues with all of that weight.
I found this website: http://www.ecalc.ch/xcoptercalc_e.htm but it is a little much for me right now. Are there any other simpler calculators that ballpark things like: overall aircraft weight/ number of engines/propellors / batteries choosen / flight time?
I also realize that I might be biting off too much for a first-timer. So building something modest just to get flying is not unreasonable. But when
you live by the motto: 'anything worth doing, is worth over-doing' this comes with some difficulty. :)
Anyway, before I fall too far down the rabbit hole some sensible, experienced feedback would be appreciated.
Thanks for your time,
Mike
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Replies
mike,
im certainly not the most experienced here, but my hexa is up and running now so i can at least give you my take on things.
flying autonomous is a bit hairy, im currently running the 2.2 b2 code but will update to 2.2 b4 for next flight - so far i have confirmed that it goes where i want it to, but i do need to tune PIDs to make auto flight smoother.
im currently flying without a camera, but with a couple more succesful flights ill start testing with a gopro or similar lightweight, shockproof camera. i dont know how much my hexa weighs but i would guess in the region of 2.3 - 2.5 kilos all up flying weight. at the moment its simply the jDrones kit with the larger motors and 12x4.5 props using 5000mAh battery, at this weight it takes off at just under half throttle and has _loads_ of power to maneouvre. soon ill start testing but im sure i could carry half a kilo of camera with no problems - the goal eventually is to be able to carry a lightweight slr (canon 600d plus a lightweight lense is going to be in the region of 800g). i also need to add a decent pitch/roll camera tray that is going to add weight.
as for flying time with no load i can fly (really fly - zoom up and down, climb, descend, fast changes of direction) for 13-14 minutes on one 5000mAh battery. sooner or later i will test with two batteries in parralel, but being realistic i think 30 minutes in the air is pushing it.
ive only logged 68 minutes in the air so far, so clearly there are people here with far more experience that could give you a greater insight into it all, but i think simply getting a kit and getting it in the air is the best way to start. now that im flying without crashing (touch wood), im preparing to build a new landing gear/camera mount and then perhaps look at building an entirely new airframe - its all great fun anyway :D
regards,
james