My first T copter build

[Vidal]

This is my T copter I built. Copied it off the simple t copter design. I find there is a lack of power when fitted with camera. Having to fly it at 3/4 throttle just to hover it. Im running it on a 2200 3s battery. If I put a 4s battery in it would it make much difference. Or am I best getting new motors.

[Vidal]

Im also using rctimer 2830 1000kv motors at the moment with 1045 props

[kym]

The little calc at http://adamone.rchomepage.com/calc_motor.htm (it';s only for 1 motor so you have to adjust by multiplying and dividing different numbers by N) says you should be getting 1600 g thrust now at full throttle; I guess 1200 g at 75%. I.e. your AUW  is 1.2 kg.

It shows if you swap to 4s then 1200 g happens at 50% throttle. OK.
The motors now drawing 16a at max throttle, so are sinking 230W. Make sure they can take it.

I only have 5000 mah 4s, so I know they weigh around 500g. If you used one of them you get 150a max -- plenty to supply the motors -- but the AUW goes up 20% so hover goes to 60% throttle from 50%. The calc says you get around 13 mins of hovering time.

If you get lower capacity 4s you might get the throttle down, but the hover time will go down, too.

[Vidal]

Cheers mate. So you think ifs worth buying bigger batterys than upgrading motors?
Also what "C" rating batteries should I go for?  25C? 40C?

[kym]

The 1000 kv is quite enough, I think. Twiddle with that calculator to see what 800 or 1200 kv does for you. Not much, I think.

The cheaper larger cap 4s seem to be around 30C discharge (i.e. 150a max) and 5C charge (2.5a max).
But you only need 60a max (according to that calculator) for your tri, so if 25C is cheaper go for that.

I';ve been using the cheaper brands (look -- what ancestors weren';t Scots or Jews were Scandinavian; and they all know the value of a penny) out of HK and they';ve worked fine so far. No fires, explosions, or swelling. And I';m a but if an idiot using those super-programmable chargers; so it must be fine for normal people. :)

[Vidal]

Cheers. Im using 30A esc. Will I need to upgrade them if I use a bigger battery then.

[kym]

At max revs each motor should draw only around 15a with 1045 props and 4s battery.
So if each esc is 30a then fine.

I haven';t looked at the specs of the RCtimer 2830, but *some* other-brand 2830s are rated at only 14a max.

So that might be a problem.

Usually they can take a little more than their max ratings given they get good ventillation and all. But these things are probabilities -- you can also blow a weak one just getting close to its max rating.

You also need to check if you';re moving to 4s that the esc and motors can take 14.4v.
Some are only rated to 11.1.

Again, I have pushed motors well beyond their max volts and they live on (e.g. some 12v super el cheapo brushed motors are living at 16v and seem to be fine with it), but there are the weak odd one that will blow up if you just touch the max for a couple sec.

The esc is likely to be much more likely to  (aka "probably")  blow if its not rated for 4s in its specs.

[kym]

OK. I just looked at the 2830-11 RCtimer 1000 kv and they are going to run hot. They can handle the 4s ok, but they';re rated at 210w power. So with a 4s this means around 15a. At full revs with a 4s battery you';re going to be red-lining your motors.

On the plus side RCtimer is not the worst for QC and there *should* be a bit of give in their 210w max rating.

And it';s only at max revs, which should only be used by cowboys and those going to 1800ft in 30 sec.
Mil spec is 80% thrust is the everyday max throttle setting; you only go over that for emergencies.

But if your tri is going to carry a $700 camera then you definitely want bigger motors. Better yet, don';t carry a $700 camera. :)

[Vidal]

Thanks for all the help Kym.
The esc will take a 4s battery (6~16.8v).
So I ill order a 4s battery soon.

I think I also want to upgrade my motors at some point soon. As I think the ones I have got are very Low quality.
Any idea what size to go for? I want something with more power and a little better quality but without spending more than £15~£20 per motor. Im not going to be carring any very heavy camera';s (just FPV stuff) but I do like making my own frames from wood and playing a round with different ideas so could end up been a little heavy.

[kym]

You';re in my ballpark, Vidal. :)

So far I haven';t ever needed very costly brushless motors; about 30 usd is about my limit. I tend to buy a couple extras in a batch and then just shelve the ones that score bottom on my own QC run.

I';m very very slowly building a Seeker which will carry a $700 camera for film work. So I want the
thing to be the "best" I can make it given my Judeo-Scottish-Nordic leanings in the purse department.

So far I';ve been pleasantly surprised by the NTM propdrive';s from Hobby King. I just bought 6
28-265';s and put aside the 2 that vibrated worst (I tend to mount them up and set them on
the bench, hook them into the flying electronics, and run them up to full revs with/without their prop adaptors/holders and see how much they walk or -- sometimes -- jump) leaving some very smooth-running motors for the quad. They are 300w+ 1000 kv so maybe would interest you as well. If they prove out for me they';re likely to be the "standard" for all the flying things around my place.

If you';re into experimenting, they';re good enough to handle 2 or 3 blade props from 8" to 12" at least.
Some of these prop combos should reduce vibes back to the mild whirr the basic motors put out.

I first got interested in multis through a youtube quite a few years back where someone took some nice pics using a machine that looked an awful lot like an orange crate with outrunners at the corners.
There';s nothing wrong with wooden aicraft. :)

[Leigh]

Hi Vidal,

Not sure if you';ve solved this yet, but I';ve built one of these too :-)  Matt';s designs are great.

My build thread is here) - I';m using SunnySky 980kv (170w) motors from eBay, which were perfectly balanced!  I';m using the 10x4.5 SF props from Unmanned Tech Shop (the green ones).  You will need to balance them a bit, though they are consistent at least.  My test results were 17.4A / 184W / 900g at WOT.  Motors were only mildly warm after 30 seconds (without any prop wash).  I';m using HK F-30A';s.  AUW of my version is just under 1kg and she has plenty of vertical using 3S 2200mAh nanotech';s.

Hope that helps - I';m new to the forum, but I';m happy to help / share any experience with my fellow hobby enthusiasts :)

Cheers

Leigh
Aussie on the loose in Belfast, NI.

[Leigh]

Quick flight video from this morning after flashing SimonK:

Simple T-Copter flight after ESC flashing

[Gaza07]

Looks nice and stable you gotta love the kk2