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Posted by on Jun 1, 2014 in Blog, Reviews, Video

AC1 V6 :The Return

Resurrection Bonus

Well I thought my beloved hexacopter AC1 had done its last flight, and had very much decommissioned her and nicked half her bits to go on AC2 my Discovery Pro FPV Quad which I bought with a mind to replace her for something smaller, lighter and easier to get around with.

So out went her beating heart, the Naza-M Flight Controller, and her RX, and her lights, and all her video gear. I was unexpectedly sad to dissemble her for what I thought would be the last time, assumedly because I am taking down a machine that has served me well, and got me really very close to the sort of quality footage I am looking for.

The main bits you get...

The main bits you get…

And then, the following week, as I was building machine no 2, I suddenly remembered that last year I’d dropped my original Devo 10 whilst crossing a road and broken a switch on it, and that there might have been an RX1002 receiver in the box with the one I ordered to replace it. And there was ! That same day I found a GoPro USB>video cable as well (meaning I didn’t necessarily need a pilot cam to replace the one now in my Disco) and found, much to my surprise, that I could get that to play ball with my cheapy Chinese non-standard video transmitter. Channel 4 might be channel 8, but it works.

Suddenly, I was just 1 Flight Controller away from my favourite flyer living again. But resigned I was, so did my Discovery build, and concentrated my thoughts thereon. But when that was complete, and I found the gimbal problem and after much f***ing about had to send it away to get it fixed, with no idea how long that would take, my thoughts began to wander back to hex-land.

For the first time since I started all this, I was without a flying machine, a feeling I found more hollow and unrewarding than I was ready for.

But wait ! Later that same day Buzzflyer mailed to tell me they had Naza M Lite’s in stock, and being just £100 for nearly identical functionality to the Naza-M, before I really knew I was doing it, my fingers were dialling numbers and words and bank details were coming out of my mouth.

Just a day later, a nice little red box arrived, and in it, a brand spanking new Naza M Lite. And a cheapy little VTX. AC1 could fly again, and I had building to do.

The road to life

…is not as quick and easy as I’d thought, and I spent a whole day preparing the build, and the whole next day building it and setting up software / making things work. Using the broken Devo 10 I haven’t sent away with my discovery, I was able to re-route the broken 3 way switch doing IOC to another 2 way switch, so now I only have ‘Home Lock’ and ‘Off’ positions, which is absolutely fine as I have used Course Lock twice in my entire time in the hobby. My knowledge of TX systems must have increased since I broke it, because at the time I didn’t know how to mod the controls to exclude that vital switch, and that’s what made me buy another complete TX / RX set. Thank goodness for ignorance !

Also a pain in the arse to make work was the VTX – after much fannying about it transpired that my receiver is receiving on Band E and that channel 8 on the VTX is channel 4 on the goggles. Helpful. I hate those Camflyer goggles as much as I appreciate their advancedness for their time. I can see they will eventually get eaten by a Fat Shark. But anyway, finally, I could see my GoPro’s view on my field monitor, and I was ready for gains, GPS calibration, and field tests including maiden flight.

Talking of GoPro on-screen – I didn’t know their video pass-through would include an OSD style overlay ! Yep – record status, time, battery meter all appear on screen – no more checking the craft to see if the GoPro is recording or powered on ! Which in turn means we can hide its nasty big red record light from paranoid members of the public :) Note to self: the big red icon on screen means cam is in record, not that the battery on your Field Monitor is running out.

Naza-M Lite Review

There she goes, AC1 V6 just before take-off.

1st props-on power-up, AC1 V6 just before take-off.

Test Setup – AC1 V6 Heavy lift Hex (for the proper hex-addict)

  • Naza M Lite
  • DJI F550 Frame with 2″ arm extensions
  • Tiger Motor 2814 770kv motors
  • DJI 30A Opto ESC
  • Turnigy 7200 LiPo
  • Aeroxcraft Landing gear / brushless GoPro 3 Gimbal
  • 12V DC regulator (VTX, lights eventually)
  • Gemfan Carbon Fibre 11 x 5 props

Here’s a vid of me talking through the setup and doing GPS calibration…

That’s why I’m here – it’s the furthest I can reasonably get from the built-up areas of town and away from magnetic sources of interference for the GPS calibration.

How Lite ?

Good ? Yep.

Good ? Yep.

It’s a small, red box, slightly smaller footprint than the old Naza-M V1, but otherwise identical in port layout. It’s a solid, well built box, and it comes accompanied by a GPS IMU, a stand / fixings, some 3M flat  double-sided adhesive discs, the V-Unit power conditioner / LED module, 8 short servo jumper leads and a USB cable. Everything you need from a flight controller except waypoints. And we can add those later, although admittedly DJI would make that easier for me if I’d bought the Naza V2 for £100 more, which would let me use their own OSD / expansions etc, which isn’t the case on the Lite. Any functionality additions here are going to be software or third party. But as long as it does the essentials including RTH, that’s all I need. It already has more features than I am going to use (IOC anyone?), so that’s very good VFM as far as I’m concerned.

So the build commenced, and to the field I subsequently went, where I did the GPS calibration, and took off for this, my 315th hour of airtime and maiden voyage with AC1 V6, new heart and eyes intact !

What no Auto-Take Off ?

And straight away, there’s the first difference between Naza M, and the Lite version – Auto take-off has gone ! Now the throttle behaves as it used to in earlier versions of the Naza software, which I actually find more helpful than the auto take-off, which isn’t always as flawless as it could be and is harder to control if it goes wrong. I do wish the documentation would tell me these things. I didn’t know Naza M was going to suddenly auto-take off before it did it, and I didn’t know this one wouldn’t until it didn’t !

The main bits you get...

The main bits you get…

Another difference is in hover point. All previous machines on Naza M V1 have hovered at  exactly 50% throttle (apart from that one time when hover was at 75% when I massively overloaded one of my early quads). Not any more. Might be a gain problem (will test that next flight) but now hover is at just 37%. I didn’t realise how problematic that might be until I forgot and did a long slow pan at 50% and wondered why I was 300ft higher at the end of it, and more so when I needed to descend quickly, which took my throttle perilously close to the 10% motor cut-off point to get a decent drop rate. So that’s dodgy, and needs fixing. I had put my gains on X1 on a rotary with limited travel so I could adjust pitch % roll gain on the fly, but will assign vertical gain to that next time so I find the right setting that makes that 50% again.

Flight Characteristics

The two 8 min 30 flights I had were rather rewarding, and I was again impressed by just how smooth and straight the DJI budget box flies, and what amazing value it is for the cash. Yes, once you’ve bought it you’re on your own, and DJI customer service really doesn’t give a shit, but my god, what they give you for £100 and easy easy setup is nothing short of brilliant. Whereas older software Assistants have been cheap looking and badly spelled, with the new Lite Assistant there is none of that, and it has been similarly overhauled with its bigger brother, and shoehorned all that control into really quite a useful, informative and attractive GUI. You can do everything here including updating the firmware, though no need, as I’m on version 1.0, the first and only Lite-specific firmware.

Another photo of the same 2 red things.

Another photo of the same 2 red things.

One thing – notable by its absence was the RX protection feature which can theoretically stop flyaways caused by control signal disturbance. In the Naza M software this is an On / Off button, but in the Lite software it is missing, hopefully turned on all the time by default, not missing as a feature !

Back in the field, GPS worked well and was found quite quickly, although it did get lost momentarily once or twice at height, which surprised me (High in empty sky is usually where reception is best).There was a small moment of potential panic when I first realised that 40% was not making my UAV descend, but once I knew about that, landing was no problem, and I was careful to never to throttle below 20% as I brought her in, which was just about possible. My maximum drop rate seems to be about 3m/sec and that’s 21% on my TX at the moment, where it should be 30-35. Vertical gain, I hope, because if it isn’t that I don’t know what I can do about it, other than run smaller props and get correspondingly shorter flight time. Or replace Gemfan Carbon Fibre 11″ x 5″s with Graupner 11″ x 5’s, which have a slightly thinner profile and cut the air more.

Gaining ground

Today’s gain settings were:

P120     R115    Y130    V140 / AP130     AR130 with P and R on X1 Aux 5 live adjust with the travel limits set to +/- 35%.

No yaw(n)ing, thanks.

Interestingly, despite this being a pretty much identical drive setup, bar the Naza Lite, I didn’t have a single sign of the yaw problem that had been getting slowly worse in recent flights on the Version 5.5. The Naza wasn’t on my blame list. Perhaps it should have been, ‘cos with the Lite, that’s a problem that has vanished.

Airtime

Flight times today were very good. 8 mins 30 on both the Turnigy 7200 mAh hardcase packs I sent up. Smooth delivery to the motors from them and the FC. That’s very good for a system AUW of 3.06 KG and a overweight frame. I may have to think about bracing those DJI arms, or replacing them with TBS carbon jobbies if I choose to keep this hex rather than sell it (assuming I prefer the TBS, and can only afford to be running 1 flyer!). This being the 1st flight session, I thoroughly tried GPS mode and Atti, and the Lite handled both admirably – easily as well as its bigger brother ever did.

I didn’t test RTH or Manual or Home Lock modes as I was too absorbed in the joy of flying, but I have no reason to suspect they don’t work just as well as they do on any other DJI flight controller. But it will be interesting to see what the throttle does on RTH, because if the system doesn’t know hover is at 35%, how on earth can it descend properly ? It won’t – it might even fly off. Mental note not to try that until we have fixed the hover at 50% thing.

Some people on forums say the Naza Lite is inferior to the Naza M in terms of levelling, and flight stability. I have seen no sign of this so far, but I’ll keep you updated.

But in general, my first flight with the Lite was an unqualified success, and if it continues like that, I’ll continue to be very pleased I bought one.

First Results: Out-of-10s

  • Value for Money: 10
  • Build: 9
  • Features: 9
  • Flight Performance: 8
  • Software / Firmware (1.0 / 1.00) 9
  • Reliability: 8 (as yet unknown, but 2 points docked for previous Naza series flyaways – we’ll assume this one has that same potential !)
    Reliability is 10 when they’re not flying away, and not much when they are. IME, you might get a non user error flyaway 1 in every 200-300 flights, or if something vital to GPS falls off your craft, and you are unable to get into manual and safely recover it.
  • Crashproofness: 10
  • Manual: 6
  • Support: 0
    There isn’t any. DJI will often / usually ignore email. Only phone support is Germany.

Overall: 9/10 – If it continues to fly like it did today, it’s a keeper, and an excellent choice for beginners and advanced-level flyers alike (manual mode is meant to be full-on),  in terms of build simplicity, software setup and flight characteristics.

 Other Gear on Test…

Yep – much excites as 2 new bits of gear arrived this week, both very cheap, and both which do extremely helpful things.

A balance board like mine.

A balance board like mine.

2 Turnigy 7200s getting a balance charge...

2 Turnigy 7200s getting a balance charge…

Lid goes up...

Lid goes up…

Lid goes down.  But not very far.

Lid goes down.
But not very far.

 

 

 

 

 

 

 

and lastly, a humble £5 GoPro to VTX cable I’ve adapted, that might just save me £50 on a pilot-cam. If I’ve managed to rebalance the camera platform to take into account the weight of the cable, and arranged things so the cable doesn’t affect the gimbal’s free movement (see TBS Disco Gimbal nightmare – don’t think I could go through that twice!).

AC1 V6. Because most of her is my old faithful...

Now with Live-view GoPro. When your battery doesn’t die on take-off.

 

First up is the balance board I will be using everywhere to charge my batteries in double quick time. Or sextuple quick time if I like – I can now wire up to 6 LiPo battery packs in for recharge, which will take the same 2 hours as each would take individually. I wish I’d known about these earlier – I dread to think how much time (and in a smaller way, electricity) I could have saved. But we’ve got one now, and it’s easily travelable :)

Next up, and for the same £14 as the Balance board cost, I also continued my long-suffering quest to find the perfect device for putting my FPV screen exactly where I want it, and ordered a TX screen clamp.

I’ve tried about 8 solutions now, and this is the best so far I think, in the short time I’ve used it. A cheap but sturdy clamp and carbon fibre frame bolts your FPV gear, in my case the 7″ screen itself a large 3S 3300 LiPo, tons of cabling and some ungainly goggles (which I have to use because they contain my only receiver, a situation I shall remedy at some point) firmly to your TX handle. Fortunately, the handle on my Walkera Devo 10 looks and feels like it can ‘handle’ the weight. Sorry about that.

Lastly, I was testing the resilience, power output and max flight time of my 2 Turnigy 7200 hard case packs. I know from experience that Turnigy packs outperform Zippy FliteMax in longevity and output quality, and these are no different, being solid, reliable devices. They are heavy, at 928g each, but that helpfully balances my craft well with the gimbal and resists wind, though it does also increase gimbal frame vibration and arm warp caused by overweighting and motoring the frame,  most apparent during hard acceleration, but avoidable if flown gently everywhere.

And that was today’s flights – here’s some pics from slightly higher than I intended in some cases, while I was unaware of the throttle thing !

The ground, at today's field, from right next to it.

The ground, at today’s field, from right next to it.

Petersfield Sewage Works. Looks better than it smells.

Petersfield Sewage Works. Looks better than it smells.

Petersfield. Doin' OK for cricket pitches.

Petersfield. Doin’ OK for cricket pitches.

Some sky, from high up in it.

Some sky, from high up in it.

 

 

 

 

 

 

 

 

A whole cricket pitch at once. Can't even see me. But I am there.

A whole cricket pitch at once. Can’t even see me. But I am there.

I may do a narrated Flight Vid if I get time, but that’ll be in its own report after I get back from the almost windless day that is today ! For now, it’s over and out from me, and as always, happy flyings…

 

 

JW