Multirotor, multicopter and quadcopter discussion - The Drone thread

doofer said:
All I see is they are DJI, which is all I need to know. DJI are the 'Apple' of the Multi-Rotor World, but they must be the best right, I mean you can't even figure out how to shorten them... Anyway, you know best so have fun! :cool:
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Don't give up the day job

Motors are on, tried to keep it all neat and flowing cable wise

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Am now starting to get a bit of a buz
 
booyaka said:
updated list - any thoughts?

  • Q450 Ghost Edition LED Night Quad-Copter.. GBP10.87 460
  • Afro ESC 30Amp Multi-rotor Motor Speed C.. GBP35.84 180
  • Hobbyking KK2.1.5 Multi-rotor LCD Flight.. GBP14.07 40
  • FrSky DJT 2.4Ghz Combo Pack for JR w/ Te..GBP25.54 147
  • Turnigy 9XR PRO Radio Transmitter Mode 2..GBP63.99 1180
  • NTM Prop Drive Series 28-26 1100kv / 252.. GBP39.14 320

Sill need battery (masive choice - need some help here!) / charger / props - any pointers there?
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Charger: Imax B6 AC version. I've got one and it's fine, does the job. relatively cheap and you don't need an external power supply. Make sure you get a genuine one though.

Batteries & Props: Don't skimp on either, especially batteries. Those motors will handle 3s or 4s so looking at this chart......

8x4 - 11.1V / 100W / 9.1A/ 0.54kg thrust
8x4 - 14.8V / 116W / 14A / 0.82kg thrust
9x6 - 11.1V / 149W / 13.6A / 0.73kg thrust
9x6 - 14.8V / 285W / 19.6A / 1.05kg thrust

That give you the max thrust for each prop type and 3s/4s cells.

What you really need to do is work out the approximate total weight of the quad (add up the weight of all the components and the different batteries) Then you really need a minimum of 2:1 thrust to weight ratio, so the quad will hover at around 50% throttle.

So, reading the above chart, if your quad weighs 1.5kg, you really want at least 3kg of thrust from all the motors. 3kg/4 = 750g per motor. So you could either use 8x4 props on 4s batteries or 9x6 on 3s. The latter is likely to give you longer flight times, the former a slightly zippier flight.

As for which batteries......

You need to work out the max draw in amps for your chosen config. So here it would be around 14 amps. Across 4 motors, that would give a total max draw of 56A. The max amps a battery can put out is Ah*C rating so a 2000mah, 20c battery will deliver 40A max (2000/1000*20) so really in this example you need to be looking at a minimum of 2200mah 30c or 3300mah 20c batteries. You can go bigger for longer flight times but there is a sweet point of power:weight efficiency.
 
^^You sir - are a legend!!!!! That is a very detailed and comprehensive reply and I am extremely grateful for that.

Only thing I will add to it short term is potentially some landing gear (legs) - circa 50g total and my go pro (no gimble short term) - circa 75g or 125grams with case.

Will review all that great information later and get ordering!
 
You're welcome. I'm off sick today so bored off my ****.

Another couple of hundred grams won't make a vast amount of difference. It will hover at a slightly higher throttle and fly for slightly less time.
 
doofer said:
Just saw they are only rated 15A and suitable for 3S or 4S, I'd bin them and get something beefier. Specially on a Hex where you can end up going to 5S or 6S to increase flight times.
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He's not going to run 6S on a 550mm hex as he won't be able to run props large enough to benefit from a low kv 6S motor. 4S is fine on an F550. It's a camera platform anyway so it's not really about punch, it's about stability. And anyway, going to 5S or 6S won't increase fight time as all it does is mean he's carrying heavier batteries for a given capacity due to needing more cells. You run a higher series of cells if you need to turn a larger prop on a lower kv motor. My 800mm hex runs on 6S becuase it has to tun 15" props with dirty big 4114 motors. You can of course run 6S on a small quad or hex if you are in to acrobatic flying. Some 2000kV motors that are rated for 6S would be mental spinning at 40,000rpm but not really appropriate for an F550.

The 15A ESCs that come with the E300 are fine and work well with the motors they are paired with.
 
Rilot said:
He's not going to run 6S on a 550mm hex as he won't be able to run props large enough to benefit from a low kv 6S motor. 4S is fine on an F550. It's a camera platform anyway so it's not really about punch, it's about stability.
The 15A ESCs that comes with the E300 are fine and work well with the motors they are paired with.
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Thank you
 
Never have I been so scared about bricking it

Solder setup - If your gonna do it then do it bloody right

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Done - Each pad was fuxed the soldered

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ESC - Cut to length, braid trimmed and tinned. No going back now

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Tidy - Heatshrink was applied

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Getting there - Starting to take shape

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ESC Mounting - Large cable tie, might swap for 2 smaller ones or something other

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Laning Gear - Just to have a peak

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With the right tools this really doesn't take long so far, hour or two.
 
Looking good! Although I'd be worried about having the arms hanging off just the two bottom screws for too long although I know they don't exactly weigh a huge amount but still!

That landing gear is very expensive compared to the cheap £20 ones I've had off the web - you'll have to tell us if you think it's worth it as I was tempted!
 
TheOtherOption said:
Looking good! Although I'd be worried about having the arms hanging off just the two bottom screws for too long although I know they don't exactly weigh a huge amount but still!

That landing gear is very expensive compared to the cheap £20 ones I've had off the web - you'll have to tell us if you think it's worth it as I was tempted!
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I only did it for the photo, it's back flat on the deck now.

Landing gear was £67 delivered as on offer. Can get extra for it to make £100 in total which I might. It's not easy to build, check Youtube. I snapped a part and owned up too it. Contacted Lee who sent me a new part for free next day and didn't ask for anything back. That's service!
 
One cool add on I'm not sure if anyone has seen is a GPS tracker. Worst case she goes for a flight on her own out of sight. I can this and it txt's back a location. I've used this on rockets to 100K Ft and also sent it to my friend in Poland too track it

http://www.ebay.co.uk/itm/Genuine-G...2?pt=UK_In_Car_Technology&hash=item19e422f708

Thinking of cable tie it to the bottom in the middle of the landing gear so it's not close to play up with the GSM and GPS bands
 
booyaka said:
Couple of last questions - how do I know when battery time is running out?? Is there some sort of alarm on the KK board/transmitter etc?
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Yes, alarm on the kk2 if it came with a buzzer. Might also be worth getting one of these as they tend to be a bit louder.

As to what you set the cell voltage to for the alarm, that's a different story. Really, you shouldn't take more than 80% of the battery capacity.

I'd probably do some research for things like "lowest lipo voltage under load" as peoples opinions differ and I tend to abuse my batteries a bit.
 
Those voltage alarms that plug in the balance lead are good. They show each cells voltage which helps identify when one cell borks.
 
gandhi said:
Yes, alarm on the kk2 if it came with a buzzer. Might also be worth getting one of these as they tend to be a bit louder.

As to what you set the cell voltage to for the alarm, that's a different story. Really, you shouldn't take more than 80% of the battery capacity.

I'd probably do some research for things like "lowest lipo voltage under load" as peoples opinions differ and I tend to abuse my batteries a bit.
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top man
 
Right - research done. (i think)

Will be ordering tomorrow - not a quick build as it's meant to be from santa so probably won't get a play till then! (damn wife's rules!)

Pretty much as per top of the page with a few tweeks thanks to ghandi's excellent input.
 
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