Mike (AIMDROIX)
I'm still building – so not finished.
They were/are EMAX 650 KVAs with 11.5 x 4.7 EMAX props – came as a combo with the 4-1in-1 EScs – which I knew and liked.
I'll post some pics when I've received the T-Motors – and also do a couple of the set-up as it is right now : with just the 650 motors and ESCs assembled – after the weekend...
Re T-motors with 6s – not necessarily so: at least, according to T-Motor specs (as I have understood them) as per below:
Specifications:
KV................................................ .................................................. .........380
Stator Diameter.......................................... .........................................40mm
Shaft Diameter.......................................... .............................................4mm
Motor Dimension(Dia.*Len)............................... .....................Φ44.35×21mm
Weight(g)......................................... .................................................. .....66g
No.of Cells(Lipo)....................................... ...........................................4-6S
Max Continuous current(A)180S.................................... .......................16A
Max. efficiency current........................................... ..................(2-5A)>92%
what's your total weight? I would like to see the specs of those 650kv motors that you are using with 15in props. 650kv and 15in props might be overkill but it depends on the motors specs.
For an X8 I would use these props http://www.rctimer.com/product-1192.html with these motors, http://www.rctimer.com/product-575.html, these ESCs
http://www.rctimer.com/product-1323.html with a 6s battery configuration. I use these motors on the Y6s that I build with 15in props and they have been working great for about a year now. They might not be the most efficient but for the price they do the work. The total of these electronics for the x8 is $289 plus shipping.
On a coax multirotor you can afford to loose a motor in flight and still be able to land safely so I fly worry free with that onfiguration. Still I haven't have a failure. (knocking on wood right now. lol). I get about 18min with a 6s 5,100 mah battery.
Last edited by MAYMIDROIX; 2nd September 2015 at 09:24 PM.
All multirotor builds are expensive thus you need to do some research about what you'll buy to make sure that it will work. The Evo quad frame weights about 730g. It's actually lighter than the $700 skyhero frame kit that weights 880g. Are you using the arms extension to fit the 15in props? as the quad frame only fits 14in props. If your x8 is not lifting it means that the motors you choose are really low in power as I've seen that it's not hard to lift a 730g frame. Can you post the lift data of those motors? Usually tiger motors provide the thrust data. As your motors are the issue, you can replace them with these http://www.rctimer.com/product-914.html. They are only $18 and in an X8 configuration they will definitely do the work with a 4s battery and the ESCs that you have.
One of the most important specs to look at when buying a motor for a build is the thrust data provided by the manufacturer. You can easily estimate the total weight of your build to calculate how much lift you'll need.
Here are other customers Evo quad.
X8 quad
Here is my quad
Mike (AIMDROIX) – in answer to your commentary…
• A combination of (8) x the 380kv RCTimer motors plus (8) x 30 amp RCtimer ESCs – as per your suggestion – weights 434 gms MORE than the equivalent using T-Motor MN4006 and Emax 4-in-1 ESCs…
However, yes, there is a saving of approximately $240 for the first combination over the T-Motor combination.
Using a 4S LiPo at 14.8v and 15.5” prop, the thrust of each motor at the same ampage output – x 8 – is approximately 3Kgs LESS for the first combination than the second.
I think you should agree that this is a serious consideration in terms of having “lift to spare” for other add-ons – such as cameras etc.
Bottom line – and in simple terms – the T-Motors are lighter (by half), more expensive by a factor of around 4x but also give approximately 30% more lift under similar conditions.
So “yer pays yer money an' you takes yer choice”.
Personally, I would take T-Motor engineering excellence and mechanical quality / component longevity / design smarts etc most times as a long-term choice over anything else.
NOT that :”anything else is necessarily “bad” – just that T-Motors set a certain quality / performance benchmark. At a price.
• The EMAX MT-3506 x 650 kKv motor combination – with props and ESCs that were all supplied together and which I took for this project as offered at the time – was a very price-effective option and worked out at about 20% more cost outlay that what you are suggesting.
They offer around 660 gms of thrust at a similar ampage point (5amps) – BUT with a max sized prop of 13" x 4.
Essentially I bought them on the basis that if they initially worked for the EVO One, all well-and-good. I liked the EVO One frame, design and undercarriage solidity – as you know and we have already discussed. However, until I saw it fly, I wasn’t going to initially invest too heavily in it.
So – on that basis – if the MT-3506 don’t have enough grunt for the EVO – that is OK as well… I was quite prepared to port-over and use them on another smaller 500 size "home design prootype" project also under construction.
So for “me” and my pruposes, they were a relatively cheaply-priced, somewhat run-of-the-mill experimental “stock” set of units that could be used elsewhere.
• By preference, all my builds are based on T-Motors of one kind or another. Why..? Because my past experience is that (a) they work, (b) they are better engineered than any other brand I have tried to date, and (c) weight-for-weight they usually produce from 25% > 45% more thrust.
… But – again – “yes” they are also on average from 40 > 60% more expensive.
The EMAX MT-3506 may well have worked OK on the EVO ONE – but having read Liam’s experiences, I don’t feel like building the EVO based on these and then having to re-build with more powerful T-Motors later. So I’ll just wait till they get here and start again from scratch based on the new T-Motor combination.
I might, however, consider your suggested ESCs as they are indeed half the weight and also one-shot – as compared to the EMAX 4-in-1s. So that suggestion at least is viable and worth thanking you for.
Finally – this is about as much as I intend to write on the subject for now – until I have something to show ready-built and worth discussing in terms of evaluative performance.