EMAX Nighthawk Pro 280 ARF Review - Part 2

Be sure to check out Part 1 of my review for a better overview of this quad and background behind my reivew.  And thanks again to GearBest for making this review possible by providing me with this quad: http://goo.gl/28ZA8U

In Part 1 of my reivew I did a bit of unboxing and first impressions of this quad.  Let's go a little deeper now and take a closer look at some of the components and features. 

The frame is the same G10/CF hybrid material my 250 is made from. With the "pro" moniker in the name I initially thought this was an all CF frame since on the 250 that was how emax separated the hybrid from the CF. It does make for a slightly heavier frame at 440g published weight (which is pretty accurate according to my scale - but does not include an RX or props.) I'll go more in detail on weight later though. The hybrid material was easier to recognize this time - the edges definitely looked more like G10 than CF compared to my 250:

I really don't mind the hybrid material. It saves money but looks nicer than plain G10 and it seems to hold up in crashes just fine for me. I was initially worried that the CF veneer would hurt crash resiliance by stiffening the G10 too much...but I've yet to break anything on my 250 which is a somewhat less robust design and it's been crashed into pavement and rocks multiple times at high speed and has only a few scratches to show for it. My biggest complaint is that it looks too nice to paint which is one of the nice things about plain G10!

The AIO board is what really sets this quad apart so let's take a look at it next. At first glance I was nervous with it being the bottom plate as the motor connectors solder joints and the XT60 main power solder joints look fully exposed. Based on photos I'd seen I was fully anticipating giving this a good coat of liquid electrical tape before flying. But instead was pleased to find that it's covered in a clear conformal coating to insulate it. That is kind of hard to show in photos though. Do note the ferrite on the power leads for the VTX to help cut down interference and the same stubby landing gear that was on the 250. My landing gear on the 250 fell off in flight the first week I had it - these seem to be attached tighter than I was able to get the ones on my 250 (without stripping threads at least) so hopefully they'll last a bit longer. 

Trying to get a shot that shows the coating on the board is tricky. I played around with lights and flash quite a bit but this was the best I could do. It appears to be brushed on as I can see what look like brush strokes in it but the photo doesn't really show that. It does cover all electrical connections on the bottom. The board itself looks well made but I haven't taken the quad apart to take a close look at the top just yet - I want to give it a few test flights before doing that. It's certainly thick material and seems to be quite hefty - The CG on this feels really low with most of the weight in the AIO board and motors.

The arms are considerably wider than the 250 and are solid with no cutouts. I think this is a recent change as other photos I've seen of this quad the arms did have cutouts and some people complained of broken arms. Unlike the 250 the arms are only drilled for the larger bolt pattern used on 2204 motors - 1806's won't fit unless you drill your own holes. The arms are the same thickness as those on my 250 but are far more substantial. They're a different bolt pattern where they attach to the frame as well so it doesn't look like it would be easy to swap the older (probably lighter) arms onto this frame. The motor wires are nicely protected with wire mesh and heat shrink - very clean. 

Speaking of motors, it's the emax (of course) 2204's I've kind of wanted to give these a try since I was so impressed by the 1806's on my 250. When I first unboxed the 1806 motors my initial impression wasn't great - they felt too light and flimsy to hold up. But they've given me no problems despite me running them in the desert heat with 6045 HQ props for over a year - including quite a few hard crashes and being buried in the sand a couple of times. I've been considering getting a set of the 2204's to try on my Twitchity 230 so I'm excited to have a set to try now! Maybe I'll finally build a thrust stand and see how they do compared against the Cobra 2204's on my hex....

The VTX is the one thing that really concerns me the most about this quad. I love that they added antenna holes in the top plate. But then they went and mounted the VTX out here with the antenna attached directly to it fully exposed in a crash. I don't expect the VTX to survive many crashes before the SMA gets broken off. I'll have to take it off and take a close look to see how much support there is - maybe that plastic housing has more thought into it than it appears. The little switch on the side controls the power output of the VTX 20mw default or move the switch to the back and go for a full 200mw. Between the switch and the replaceable antenna I don't think that has any chance of passing part 15 approval with the FCC - but it's nice that they at least give the option for people without a license to try and stay within the spirit of the law if not the letter.  The other major issue I have with the VTX is that even though it says "32ch" on it it's not actually a 32ch TX, it only supports the 19 channels between 5725-5850MHZ the first batch of VTX's were actual 32ch TX's but emax has revised the design and updated the manual with a new frequency table eliminating quite a few channel options.  Their reason for this is to try and pass FCC certification - but as I already pointed out with the power switch and detachable antenna there's basically no chance of them getting this part 15 certified so I'm not sure just what they're thinking.  

I'll get more into this in Part 4 - but the whole FPV setup on this quad has been a bit of a dissapointment for me.  With the limited frequencies I can't use the built in TX with my Boscam RC305 RX, and the connectors for the camera are smaller than every other board cam I've used so it's not easy to swap a different camera either.  I haven't been able to test the stock camera due to the non-standard connectors and the TX issues - but I've heard a number of reports that the stock CMOS camera is prone to jello and just doesn't work very well.  So again having standard sized connectors would be nice on a quad aimed at beginners so they could easily swap to better video gear.

Also on the back is the light bar. It's a COB light and it's a monster. The manual says it draws 4watts and warns not to touch it because of how warm it gets! There's a small switch on the AIO board you can use to turn the light on and off - and at 4 watts I'm glad they include that as that's enough it could impact flight times a little bit. As with everything else the wiring is done nice and cleanly with wire loom and heat shrink. The wires terminate in a plug so the light bar is easy to attach/detach. It's held on with two plastic mounts that screw to the rear arms. One slightly disappointing thing is that only the rear arms are drilled for this - so no swapping a front arm to the rear unless you want to give up the light or drill a new hole yourself. Seems odd that they'd do that - I would think making all the arms identical would make manufacturing easier. I wonder if it's an oversight due to the change in the arm design. 

Also visible in this shot is the integrated XT60. I really like that touch, though the provided connector is a bit tighter on my packs than most. It will probably break in with a bit of use but is kind of tricky to get to. Also it's kind of close to the props so a little scary to reach in and unplug. With all the wiring on the one AIO board the inside of this quad is empty so you can actually mount your battery inside it for extra protection - between that and this integrated power connector the overall setup is really clean:

So - how does this stack up to it's older sibling the original nighthawk 250?  

As I already mentioned the earlier 250 is actually a 290 as well. But they're both "250 class" just a bit bigger than 250 to accommodate 6" props. Side by side on the table or in the hand the two are very similar. Though my 250 is surprisingly enough noticeably lighter. The new 290 feels bigger and more substantial - but put them next to each other and the differences really are minor. The center section on the 290 sticks out a bit further on both ends (about 1/2"-3/4" overall but mostly in the rear) but that's about it:

Stack them on top of each other and you can barely see the bottom one they're so similar:

The arms however are noticeably different. I already noted that they're wider and solid with minimal cutouts. But seeing them next to the 250 arms really shows just how much wider they are despite being the same thickness. There's also more material around the motors on the new arms. I suspect this was done to accommodate the tilt mounts - but also provides a bit more protection for the motors in a crash. On the 250 arms 2204's would be right to the edge of the frame and get basically no protection. I don't much care for the look of the new arms, they do seem more substantial but since I've yet to break an arm on the 250 I'm not sure how warranted that is.

Side view is where things really look different. The AIO board really makes for a super super clean build compared to the jumbled mess on my 250! Yeah, I can clean that up a bit better, and with the video gear removed my 250 is really clean. But fitting the ESC's into the 250 was tricky and the power board and FC take up a good bit of space. I would have rather seen the built in ESC's rated for 20A than 12A (especially with 2204's and 6045's) but emax 12a esc's do seem to hold up to that setup so I'm not really anticipating any issues. With outside temps over 110F right now I'm sure I'll uncover any heat issues when I do my test flights!

No props, no RX and no VTX antenna it weights in at 424g on my scale - the official weight is 440g and with props and antenna it actually comes in at 467g for me. I'm kind of surprised at that weight honestly because....

My 250 only comes in at 347g ready to fly (other than a lipo):

So despite being a cleaner build there's quite a bit of extra weight compared to the original Nighthawk 250, where's that weight coming from ?!  Let's investigate!

I suspected the plastic case over the VTX may be a culprit - but it's actually only 7g, not too bad.

What about the lightbar?  Well that is a bit of a porker at 12g!

The plastic case over the VTX does add some protection...but doesn't do much at all to help support the SMA connector which is what really needs protection IMHO.  The tape that actually mounts the VTX to the frame is VERY strong - the plastic case is just there for protection not to hold the VTX on.  If you stick with the stock TX I'd STRONGLY suggest taking the case off, cutting off the spot where it mounts, moving it inside the frame and using a small coax jumper to mount the antenna on one of the holes in the top plate instead - that way would be lighter and provide more protection to the VTX. Checkout this post in my forum thread for more detailed shots of the VTX and how it mounts: http://forum.flitetest.com/showthread.php?21218-EMAX-Nighthawk-Pro-280-ARF&p=224750&viewfull=1#post224750

As for the light, I took it off and don't miss it.  It's BRIGHT but it's heavy and it sucks down 4w so it does affect flight times slightly.  If you need a light, it might be ok.  But I'd rather go with some strip lights that weigh a lot less and are cheaper to replace.  

How about the setup on the quad?  Well, the stock setup is pretty stock.  It's baseflight (it was the latest version that had been released just a few weeks before I got the quad so that was kind of impressive) but there's no attempt made to customize the configuration.  You're expected to calibrate the ESC's, the PID's are baseflights defaults, the flight modes aren't setup - it's just a stock install of baseflight and you'll have to set it mostly like on a self-built quad.  It will fly on the stock tune, I did all my test flights on it, but it's FAR from optimal and most people are flashign to cleanflight immediately.  

The ESC's are running blheli and support oneshot (you just have to enable it in Baseflight or Cleanflight and the ESC's will autodetect) but for some reason they twitch at zero throttle which is usually somethign only AVR based ESC's do and these are definitely silabs based.  Odd.  Emax has also modified blheli so these won't work with the blehli suite software - you have to use stick commands.  According to emax the "brake" setting on them is actually damped light - I enabled it using stick commands (and increased the motor PWM from 8khz to 22khz because the sound motors make at 8khz is like nails down a chalkboard to me) and it does seem to have an effect...but I'm not convinced it's actually damped light.  Just didn't make the difference I've seen damped light make on other setups.  I'm still looking into reflashing the ESC's with official blheli.

Digging a little deeper I took the AIO board off to see about reflashing the ESC's.  The XT60 was a bit of a tight fit - but that was the only real difficulty in removing the board.  The nuts are 5.5mm which is a bit of an odd size but thankfully I had a socket to fit.  

The main processor is a good old STM32F1 and the sensors (MPU-6050 and standard mag) are on a little daughter board that has two layers of foam tape under it. I'm guessing that was done to minimize vibrations to the sensors...though given my experience with motos wii board I question the necessity. emax probably just found it easier and cheaper to add a daughterboard, flat flex cable, 2 connectors and some tape than it was to have someone customize the filtering/tune to work well with hard mounted senors. Heck this thing is running 3500 looptime out of the box.  You can also see the programming header for one of the ESC's in the lower left just to the right of the processor for the ESC.  The header is the 4 square pads right where my light is reflecting the brightest.

Those two largish components near the top of the photo with their center leads cut off are the main power regulators. I've noticed that the board under them gets quite hot as long as the battery is connected, which isn't very surprising - but just how hot they get is.  I've seen temps of over 100F after just a minute or two of having it plugged in.  But after a few weeks of flying in 105F+ temperatures outside I've yet to ahve any heat related issues.  

So how does it Fly?  We'll let's give it a try on almost stock settings.  I did adjust the PWM on the ESC's and enabled damped light before this.  I also setup failsafe (ALWAYS setup failsafe before flying!) and configured some flight modes before this Maiden flight:

Once again thanks to GearBest for providing this for review: http://goo.gl/28ZA8U

This is also available as a RTF setup with transmitter included here: http://goo.gl/8NOypn  I don't have the RTF version so I can't really share any details about it.

Check out Part 3 for my final thoughts on this quad!