RC India

After making my first reptile quad and immensely enjoying it, i have decided to take the plunge and make a hexcopter.
parts ive decided: all from HK
Quanum 680 hex frame
Afro 30a esc
10X4.7 CF props
turnigy multistar 3525 850 kv motors
hk gimbal drop
DJI naza M lite
Thats most of the major components ive decided. any takes on the feasibility?
any suggestions, advice or changes will be appreciated :)
Theoretically it seems okay and most products are the ones suggested by hk.
thanks :D

Good luck  :thumbsup: try and post a build log since we don't have many in the Multirotors board.

:thumbsup:

i suggest you consider lesser kv motors like 3508-640Kv

Why is it so Mr. Bhanu.

:thumbsup:

thanks for the suggestion but i already ordered the above motors. hope it will work fine :)

lower kv motors will give a bigger size multirotor  (like 680) more thrust to carry heavy payload, since the bare frame waight itself here is 740gms.

but lower kv motors will require higher cells in series to run an 13" or 12" prop.

Here is a weight breakdown:
frame:740 g (with fixed landing gear)
motors: 58x6= 348 grams
ESCs: 26.5x6 = 159
FCB: 66.3 g
Gimbal drop: 100 g
Misc cables, connectors and props: 100 grams
Thus, the AUW = 1514 grams + LiPo (300-500 grams)
Max motor thrust (attached from HK website) = around 900 g with 10x4.7 props and over 1000 grams with 11x4.7 props.
Thus, with 10x4.5 props the max weight should be no more than (900*6)/2 = 2700 grams, allowing for payload of around 800 grams (assuming LiPo weighs around 400 grams).
With 11x4.5 props, the max weight should be no more than (1000*6)/2 = 3000 grams, allowing a payload of 1100 (same assumption).
These tests are with a 3S LiPo though I am not sure of the accuracy of these results. Please confirm which LiPo you are using for a more accurate breakdown Mr. Yash.

Thanks for the time and calculations.
yes ill be using 2 3s 3300mah in parallel each weighing 250gms.
also what prop would you suggest 10x4.7 ot 11x4.7?
I cannot use a 4s battery as the motors are rated only for a 3s according to th HK specs.  ???

Also regarding the payload capacity quite frankly ive just built one quad  before this and am still working on my skills. Need to get the confidence before i actually get into fpv or aerial photography. That is why i havent purchased a gimbal. My plan is to buy a gimbal and an action camera once i am perfect with flying it and confident. that is why i did my payload calculations considering a 3 axis gimbal at 330 grams and action camera at approx 100 grams. 

So now your total weight is around 2000 grams (1514 + 500 for the LiPos). There is no reason why you would need to use 4S since 3S is good enough. I would suggest you choose a prop based on how much payload you need to carry since with 10x4.7 you can carry 700 grams and with 11x4.7 you can carry 1000 grams. Your ESCs (30A) should be able to handle the current since even with 11x4.7 the motors only pull around 18 Amps and 23 Amps max. The only thing is that your motors might heat up at that draw. I am not sure about this but I would suggest you go for 10x4.7 for greater responsiveness and 11x4.7 for greater efficiency and payload carrying. BTW, are you using SimonK ESCs? As for the time, I am free all day  ;D since I have holidays after finishing my 10th boards so I am happy to help.

I will be going for a 10x4.7 prop as my motors are 850kv. I dont think an  11 inch makes sense with a higher kv motor. Maybe with 620 it would have. here is what a read on a website: please correct me if i am wrong.  ''A smaller prop is easier to stop or speed up while a larger prop takes longer to change speeds (inertia of movement). Smaller prop also means it draws less current, that is why hexacoptors and octocopters tend to use smaller props than quadcopter of similar size.For larger quadcopters that carry payloads, large propellers and low-kv motors tend to work better. These have more rotational momentum, and will more easily maintain your aircraft’s stability.'' and yes the escs are SimonK :D

Good choice. Most of my advice comes from Oscar Liang's blog too. Eagerly awaiting a build log of your hex  :thumbsup:

Yes thanks a lot :D
One set of components will be arriving by dhl express today  :)

One thing you should take care, your LiPo's discharge rating (C rating) should be high enough to handle the currents.

thanks mr sooraj
could you elaborate on it? havent yet given thought to the battery purchase

How much is the max. current draw for one of these motor at 3S and 1047 prop ?

As per the graph I posted, it is 16 Amps so the total draw is 16x6=96 Amps. In parallel, the LiPo capacity is 6600 mAh. Since he is running two packs in parallel there will be twice the available current. Thus even 20C will be more than enough since it can supply (3.3*20)*2= 132 Amps. @yash, just make sure your LiPos are of the same discharge rating since if they are different, the lower rated one will heat up. Also, when you run them together, they should be charged to roughly the same amount.
EDIT: Just thought I should mention, 2 LiPos in parallel are usually heavier than one of equivalent capacity. You could go for a 6600 mAh battery with minimum 20C discharge.

thanks for that info. only reason i thought of parallel packs is because i have one with me already and the batteries here are way too expensive( larger capacity ones) and shipping form HK also is expensive due to their weight (around 500 gms)
also i did the calculations on ecalc and it is saying that i get a payload increase of almost 600 gms and flight time increase of 1 minute using 11x4.7 props instead of 10x4.5. now i am confused as i thought larger props would decrease the flight time on a 850kv motor  ???
also a 12 inch prop will increase payload to almost 1.8 kg and flight time to 11.1 minutes. but this motor is rated for only 10 to 11 inch props but there are reviews of people using it with 12. what would you recommend?

received the frame today. completed the landing gear,gimbal drop and arms assembly. quality is good and very sturdy. will assemble the rest once the electronics arrive this week. paid rs3200 customs on the order worth 170 dollars without shipping(203 dollars with shipping)

you always have the option to experiment, props are cheap.....
And in terms of battery it's better stick with what SK1701 said.

From Oscar Liang's blog, I read that larger props are more efficient, just like a swimmer with longer arms will need more effort to swim but will be more efficient. Using 12 inch props is not a great idea, some people may do so but generally it is best to follow the recommendation since the motors may heat up or draw too much current damaging the windings. Please share a screenshot of your eCalc calculations with 10, 11 and 12 inch props if possible. The build so far looks great  :thumbsup:. It is really exciting to open packages. Looks like Christmas has come early for you this year. ;D

thank you :D
will have to do some research before getting the battery it seems.
here are the ecalc results for 10 11 and 12 inch props

No wonder you were getting such high values for payload. It seems the weight of the battery has been taken only as 93 grams  :o. While quoting flight time, it is a better idea to quote the mixed flight time estimate rather than the hover estimate. Anyway, according to eCalc, your motors wont draw more than 18 Amps with 12 inch props so maybe you could try those. Just check the motors periodically to make sure they don't get hot.

no no thats the per cell weight if you check under the battery column on the bottom left you can see the weight is proper ie 558 gms.
exactly but i dont want to risk damaging the motor shafts with the 12 inch prop!

Oops. I should have looked more carefully. Anyway, you won't damage your motor shaft. If anything, you will damage the windings. The HK website says these motors can handle 23 Amps for upto 10 seconds and the working current is 19A so it is your call.

true when I order the props ill first get some plastic ones of both sizes to check and then get the carbon fiber ones of whichever performs better  :)

so recieved another set of components
completed frame assembly, motor mounting, esc wiring with extensions, prop guards and power supply
waiting for the next set of parts to proceed  :)

That's a really nice looking hex  :thumbsup: One tip I would like to share is to use Loctite Blue or Anabond blue on all the screws that have metal on metal contact such as the motor mounting screws, prop adapter screws and parts of the frame. Put just a drop on each screw and tighten it. This will prevent loosening due to vibrations. Make sure to use only a drop otherwise the screw will become practically welded and almost impossible to remove. I also saw this video on ESC customisation. It is a bit of a risky procedure but you might want to try for aesthetic reasons. http://www.youtube.com/watch?v=eo6LHCcbuoM#ws (http://www.youtube.com/watch?v=eo6LHCcbuoM#ws)

yes i read the thread gluing thing in the forums but what im worried is that iff the glue seeps in the screws could get really hard to remove in case i have to adjust or change anything. so ive decided to do that once the quad is ready tuned and perfectly flying :D
as for the esc customization, its far too risky with my level of soldering skills plus escs are already under the center plate and wiring is through the cf tube hence it is almost invisible :D

UPDATE:
Assembled everything with the naza m lite
8000mah 3s battery
2 axis gimbal etc
using the rcb7x on this one till i get something with more channels
ordered an fpv set from quadkopters and also have ordered fpv goggles.
will update once thats done.
it flies well and is very stable. havent measured flight time but it seems to be okay for now :D

Great job  :thumbsup: I would love to see some flight videos