To those of you that choose to upgrade the vtx in your hawk 5, like I did with the AKK infinite VTX/DVR (in this walkthrough here) I've updated my recommendation for the powersupply. Previsouly I relied on the flight controller's 5v BEC circuit that also powers the receiver and of course the board itself. I've now updated this recommendation to use the VBAT (or VCC) power supply instead assuming of course your VTX can take up to 24V as most modern full-sized VTXs can, including the AKK infinite I installed. This is because the BEC struggles at higher output making the video feed noisy. Over the longer term this is likely to irreversible damage the BEC rendering the flight controller pretty well useless but not before having random failures as a result of the compromised BEC. Picture below is using the power supply from the original VTX - the flight controller's 5V BEC:
The Emax Hawk 5 is arguably the best bind and fly quadcopter going as I found in my initial review but can also be greatly improved with a few budget modifications as I wrote about in my blog on bang for buck improvements. I do however see a number of people complain about the stock Emax Hawk 5 vtx however mine has been functioning well. That being said, you cannot adjust setting in betaflight OSD via smart audio or tramp telemetry which is a let down on a 2018 quad. In the interest of sharing I've removed the stock VTX and replaced with one of the larger VTXs currently available (the AKK Infinite VTX/DVR) to prove it can be done.
The VTX I chose is the AKK Infinity DVR VTX. This is very similar to the HGLRC VTX/DVR that was reviewed here. As the name suggests this is a smart audio VTX in 30.5mm VTX with a built in DVR. I chose those for 2 reasons: First it's big. If I can fit this in you can fit anything! Secondly I like the DVR for recording breakup-free footage. For me I like the nimbleness of the Hawk 5 and don't want to weigh it down with a HD Cam. Other key features of the VTX/DVR:
Just quickly I used the following tools and parts in the instructions below:
Please note all the pictures below relate to the install of the AKK Infinite but install should be identical or at least nearly the same for others. I had to remove the buzzer and relocate the receiver for this VTX but depending on the size of the VTX you install you may need to do only one or neither. Follow picture left to right then down. All pictures will enlarge if you click on them.
What did I learnt from the install?
Firstly I can appreciate how Emax has made the most of the space with compact components. If I were to do this again I'd consider a smaller vtx to see if I could get away with removing less components, possibly an AKK FX2 ultimate mini half board or even an AKK nano 2, nano 3 or Oscar's backpack which may allow you to keep the buzzer AND receiver in place. That being said I'm really pleased I installed the DVR unit for extra functionality and did manage to retain a proper SMA antenna mount.
Set up and flight performance
I'm pleased to say that on the very first power up it functioned as expected. All Ineeded to do was to allow smart audio as a peripheral funtion on UART 6 in betaflight and smartaudio (VTX channel and power control through OSD) was fully funtional.
For video signal performance please see below for goggle DVR recording comparing the stock VTX on 25mW and 100mW compared to the AKK Infinite VTX running 25mW, 200mW, 600mW, 1000mW. A quick spoiler: 1000mW was unstable. This is likely because of the load the VTX and DVR units place on the 5v flight controller BEC (which also supplies the camera). 2 solutions here - run at 600mW or below or power the VTX from the VCC pad (picture below) instead of the 5V supply used by the stock VTX. This gives the VTX full access to battery power which is fine since it is rated up to 26v. For me I'll run 200mW maximum since I don't like to overload BEC circuits since it can make weird things happen - FC brown out, flickering OSD etc.
Update December 2018: I now recommend using vbat/vcc to power the vtx as covered here.
Overall for me video performance was comparable. The AKK VTX does however offer greatly improved functionality:
I'd definitely recommend changing the VTX for a different unit that supports Smart Audio if your VTX is not working as well as you'd like, but as you can see above it does take some planning and work. Even if it is working well some of the extra features that can be had on more modern VTXs may be worth the jump especially if you are confident with this type of work. Even if you aren't confident this guide should hopefully help you. AKK tend to make a good budget VTX with a lot of features but you can subsitute your favourite model here easily enough.
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Update! I've just finished writing an extremely detailed walkthrough about how to upgrade the VTX - full blog here
The Hawk 5 ready to fly 5" quadcopter has been out for several months now and has been a real hit for Emax - so much so that it is only widely available from a stock perspective now. I have one which I've reviewed (here) and can quite easily say it is the most well-balanced and complete bind and fly quadcopter I've come across. Gearbest and Banggood currently have this is on special for $209 and $229 respectively (check out my discount page here)
My real life work means I'm always looking to improve on systems and it's no different for my quad obsession. So I've made a list of my favourite 'improvements' or probably more accurately personalisations as these are more about changing the feel of the quad to suit my taste rather than the basic operation. I'll also cover off the things I haven't touched because I've not yet thought of a better alternative.
6 inch arms
The 6 inch arms are available as a direct uprgrade from Emax rather than a third party offering. All four can be had for less than $20 so it's fair to say Emax is looking to expand their ecosystem rather than profit of these in particular. They are very easy to fit since the frame uses captive nuts and arm retention hardware is independent to the stack mounting hardware. This means you can change the arms without pulling anything apart. Arms are sold in pairs and are presently in stock at Banggood for $8.99 per pair.
The new arms will push the motors out by 15mm in each direction and the good news is EMax allowed for enough slack in the motor wires so they they don't need to be extended - making the whole process VERY simple. To start I flew with 5" props on the new 6" arms and was suprised to find how much more stable it was in regular flight. I've found examples where several pilots prefer 5" props on a 6" quad for a more stable HD platform (e.g. Gapit) or for improvements to a racing rig (Serge from Piroflip noted that his son Dolma FPV runs a 6" frame with 5" props. KababFPV who works with Piroflip has suggested this is likely due to the lesser amound of turbelent air to each prop given the additional spacing. One potential down size is the additional width but in reality this is only an extra 9mm wide on either side. Theory aside I really liked the feel of stability.
The next obvious advantage this gives is the ability to physically use a 6" prop. In most circumstances you'd need to revisit your motor choice (stator size and/or kV) but in this circumstance the seemingly low kV that Emax chose (2300kV) and and reasonable stator size (2206) means that it can swing a 6" prop on 4s with no issue. I chose to use the Gemfan 6042 bi-blade but have heard good things about the 6" LR Avan prop too. Since the quad is light and the 6" adds so much prop area, they have more than enough grip - much more than a 5" tri blade... feels like they stop on a dime. There are a number of good 3 blade 6" props available now from Dalprop and HQ but I feel the extra weight these add is unnecessary because it will take away from the response of the 'just big enough' 2206 motor. In the air hover is achieved on a much lower throttle as is everything else. Most flying is done at low to mid and the sense of control is strong. Full throttle draws a LOT of current: 135A on 6042 vs about 90A on the HQ 5x4.8x3. High throttle is less about more thrust and more about current draw suggesting the motor has probably hit its limit. This would be a great candidate for scaled throttle reduction in betaflight 3.4.0 onwards as per my setup guide. That being said the thrust is immense for such a light quad and actual battery life was somewhat similar to 5" props but so much more variable - it will be way more efficient than 5" at light throttle but way more inefficient at heavy throttle. For the cost of the arms and props and ease of install I'd definitely recommend giving it a try. The video below shows my first flight on 6" props, please turn the sound down. punch outs at 0:23 and 0:40.
Changing the props
I love the idea that Emax created the 5" Avan Flow around the Emax LS2206 motor on the Hawk 5 but I just don't like the feel. Don't get me wrong, I love the idea that the weight is kept close to the hub and that it is durable and well balanced but just don't like the way it delivers power. To me the HQ props feel much more familiar and I've found the 5x4.8x3 V1s with it's relatively steep pitch is a good match for the LS2206 2300kV stock on the Hawk 5. The other thing I prefer over the V1s design is efficieny. Top speed 'feels' similar but maximum current draw is only 90A on the HQ 5x4.8x3 but 110A on the Avan Flow using my best batteries. Plenty more props for me to try including the HQ 5.1x5x3 but at this stage I'm really pleased with the 5x4.8x3
I find the video transimission surprisingly good on the Hawk 5 but the antenna solution is a let down. Dipoles are fine for flying alone but the Hawk 5 one is not secure. I did the cable tie/heatshrink trick to secure but still lost it after and upside down landing anyway. I wasn't bothered though, because my race club doesn't allow dipoles as a vtx antenna because of the increased likelihood of bleed over to other channels. Emax were good enough to include a UFL to SMA cable and 2 x excellent Emax Pagoda LHCP antenna but recommend a rubbish way of mounting them with cable ties that is just not secure and risks the antenna getting caught in spinning props. The best solution in my opinion is a 3d printed one. I don't own a 3d printer but a service like 3d hubs means I can download an appropriate file from Thingiverse and have it printed and delivered to me - it was only about $5 for 2 printed mounts. Here is the design I recommend since it elegantly incporated and SMA VTX antenna mount and receiver antenna mount using forever tubes. I had a 3d printed mount from an old floss 2 frame and found the standoff spacing is identical (31mm) so have just used this for now. Here is the link for that design. It's a tidy solution that keeps the antenna safely away from the props and allows a good and for a racing quad that is commonly tilted forward fairly heavily.
What I haven't changed:
Motors. Many (including myself) questioned the choice of 2206 2300kV motors when Emax had the 2207 mid-high kV variants available. I no longer question the stator size or kV as I think both are an excellent match for this quad - the 2206 is plenty for a lightweight build and the 2300kV offers great efficiency and flexibilty as per 6" props whilst still being suprisingly powerful. The only change I would make is going to lower kV IF I decided to run 6s which this stack is apparently capable of - Conrad Miller (Furadi) is an EMax team pilot and has run 6s on a magnum stack with a 1700kV motor. If I did go for a low kV motor the standout option for price/performance in my opinion is a Brother Hobby Returner R3 2207 1700kV which is only $15 under the HobbyCool Logo. I've used these on my 6s race build (blog here) and they are super nice.
VTX. The included VTX is limited to 200mW and has no smart audio. Many users have reported poor performance or reliability problems although I have found signal and reliability to be just fine. If it were to die I'd probably install the AKK infinity VTX DVR combo or HGLRC AIO VTX DVR (reviewed here). The stock Hawk 5 is too light to carry an HD cam so an onboard DVR would be a satifactory backup. Given the current VTX shares a stack layer with the XM+ receiver this would need rewiring and I can't bring myself to do this on a receiver that is currently working well for me.
Camera. The Foxeer Micro Arrow Pro as on the Hawk 5 is hands down my favourite budget camera. It gives consistent performance regardless of sunny or overcast day unlike many of the new CMOS cameras. An exception to this is the Micro Eagle which is the best camera (IMO) period. It's not cheap though so I can't justify replacing the Arrow pro but this is the only camera I'd uprade to.
All of the mods I've included here change the feel of the quad except for the VTX antenna mount which is a MUST HAVE in my opinion. I do like the longer arms with the HQ props and this is what I've settled on but this is a feel thing more than anything else and was not expensive so, why not?! I'll only replace the cam and VTX if mine break down. If I break motors I'll replace like for like unless I change the whole fleet to 6s which is presently unlikely.
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