215 Hopper FPV Rebuild

I finally have the design of the 215 Hopper at a point where I think it is fit for purpose as an FPV copter. It can now sustain a heavy grounding without terminal damage. I still won’t claim that it is as durable as a carbon plate design but I am now happy to release it. The camera pod is perhaps the least durable part of the design however I am still flying with the first one I printed and it has served its purpose protecting the flight cam. I do intend to upgrade it at some point but that will probably come after the custom camera pod for my Shendrones Tweaker.

If you’re interested in building a 225 Hopper FPV then you can find all the files you will need over at Thingiverse


215 Hopper FPV
by ataylor60

215H-FPV-22

I have made 2 changes to the previously seen FPV design iteration to realise these durability improvements. Firstly I scrapped the idea of running the motor wires through the arm tubes. Whilst I think this still has merit, for now it was causing more problems than it was solving. I will perhaps look at it again in the future. I have however maintained a similar motor mounting arrangement. All 4 M2 threads are used to attach the motor to the top half of the motor mount with the motor wires aligned with the arms. Separate bolts are used to clamp the motor mount to the arm tubes.

The second change is specifically to do with the clamping bolts on the motor mounts. Now rather than simply clamping on to the tube end and relying on friction to keep it in place I have created a positive interaction between tube and mount.

215H-FPV-18

As seen in this exploded view of the motor mount the tubes are now drilled with a 5mm hole to accept the same 15mm M3 standoff that is used throughout the rest of the frame build. The 2 printed parts of the motor mounts then snap over these standoffs and are clamped together with M3x8 button head screws. The only trick to this is that the standoffs must be screwed in to the top half of the mount before the motor is subsequently mounted to that before it is finally installed on the arm.

At the same time as making these motor mount changes I decided to keep things simple and remove the LED tail lights. Now the same 2 parts are used at all 4 corners. Speaking of parts, the image below shows all the parts required to build the 215 Hopper FPV edition.

215H-FPV-21

Included are (in order from left to right, top to bottom):

  • 2x 215H 101 12mm x 10mm x 183mm Carbon fiber arms
  • 1x 215H 107 Top plate PDB
  • 2x 215H 106 Bottom plate
  • 4x 215H 138 Motor mount bottom
  • 4x 215H 137 Motor mount top
  • 1x 215H 103 Frame side
  • 1x 215H 111 Frame side with USB access
  • 3x 215H 108 Tube clamp
  • 1x 215H 102 Tube clamp with antenna mount
  • 1x 215H 130R Camera pod right side
  • 1x 215H 130L Camera pod left side
  • 1x 215H 126 Video Tx pod
  • 2x 215H 134 Camera pod spacer
  • 1x 215H 132 Camera pod rear post
  • 1x 215H 133 Camera pod front post
  • 1x 215H 131 Camera pod base plate
  • 18x M3x15 Round standoff
  • 2x M3x20 Round standoff
  • 40x M3x8 Button head socket screws
  • 4x M3x10 Nylon screws
  • 8x M3 Nylon nuts

All the 3D printed parts are printed in ABS with a 30% infill, 3 outlines, 3 solid bottom layers and 4 solid top layers. Colour is unimportant but I find it looks its best if the frame parts are a bright colour (as seen here in orange or previously in red) and the accessory parts are black.

The 215 Hopper FPV is designed around a fairly specific set of components. This is not to say that other parts won’t work on the frame but rather that the positions and space allocation work best with what I have used. My recommended build uses:

  • DYS 1806-2300kV motors
  • 18A ZTW 18A Spider series Opto ESC’s
  • Naze32 Rev 6
  • 25mm Plastic housing FPV camera such as the HS117 or HS1189
  • Lumineer TX5G8 Pro power switch vTx
  • FrSky X4R-SB receiver
  • Pololu 5v converter
  • 5cm 90° bulkhead SMA extension

215H-FPV-20

An important detail to note when assembling the frame is that the flight controller should be in the front half of the craft. The reason for this, as I noted on a previous post, is that the vTx pod must fit around the nylon screws used for mounting the flight controller. There are holes specifically for this purpose in the pod. Another new feature on the vTx pod is the inclusion of the slot seen below. This allows you to see what band and channel is selected on the vTx and also if it is transmitting or not. This small details makes working with this specific transmitter significantly less frustrating.

215H-FPV-19

A lot of the notes I made regarding the initial build (found here) also apply to putting together this FPV version. In lieu of a full write up for this I will direct you to that if your would like to build one for yourself. Also please feel free to contact me or leave a comment here with any questions that you might have.

There are a couple of build notes that do specifically need to be made for this model:

  1. Whilst not strictly necessary I solvent welded the 3 parts of the camera mount together (parts 131, 132 and 133). Durability has exceeded my expectations so that is probably a worthwhile step to take.
  2. As I have left over PCB’s from my first batch I have not modified the bottom board to include a hole for passing the vTx wiring. You will need to drill this just in front of where it will connect to the vTx. It should end up just inside the ‘mouth’ of the pod.
  3. As the motors are now fixed to the tubes drilling the holes through which the mounts pass is critical. They must be aligned end to end. For this I have included part 215H 139 which is a drilling jig. Print two and slide one on to either end of the arm tube. You can then use the flat sides for alignment. I suggest holding the jig with a clamp or vice whilst drilling as the thin wall carbon has a tendency to grab onto the drill bit.

215H-FPV-24

If you decide to build one i would love to see it! let me know about it here or post it up as a build on thingiverse.

215 Hopper FPV Durability

As flight hours on my 215 Hopper FPV platform increase it has become clear that the durability of the design is somewhat limited compared to the more common carbon plate design. The core problem however is not breaking parts, though this has happened, but rather pulling wires out of the motors. When the quad comes down it frequently pulls the motor mount from the end of the tube and as the propellor is often still spinning at a high rate the inertia of that then stopping is enough to pull the now loose motor off its own wires. Part of the philosophy with this design was that the motor could be allowed to rotate on the tube in the event of contact and through most all of my LOS flying this was valid and workable. It has now become evident that the sort of crashes I am experiencing whilst learning FPV flying are too much for this design.

With my first iteration of the FPV version another flaw with the rotating tube fairly quickly became evident. The edge of the hole in the centre of the arm tubes was cutting the insulation of the motor wires. In fact this become bad enough before I realised it was happening that the motor wires began to short through the carbon ultimately resulting in the quad falling from the sky (perhaps about 10m). This was the most significant crash to date resulting in a broken arm and several broken plastic parts as well as the previously mentioned motor pulled from wires problem.

215H-FPV-11

Something odd has also happened to the electronics meaning that 3 out of the 4 motors will not spin up to full power. This problem remains undiagnosed so I have shifted the FPV gear across to my other airframe. In the first image below the spilt insulation is very evident though I don’t think the wires actually shorted at this end, the crack in the tube can also be seen though it was significantly worse when removed from the plastic support.

215H-FPV-12

In this image, at the other end, the split insulation is also evident but if examined more closely there is evidence of burning from the short on both the tube and insulation of the middle wire.

215H-FPV-13

Two decisions have come from this. Firstly I have iterated on the design again with a number of changes which I will detail in a subsequent post. Secondly I am building a more traditional carbon plate design which should hopefully allow for a much better flying to fixing ratio upon which I can develop my skills. Specifically this will be the Shendrones Tweaker and as is my way that won’t be a standard build so there will be a post about that soon too.

215 Hopper FPV Airborne

Over the weekend just past I got my first solid session flying FPV under my belt. This of course means, as the title of this post also states, that my FPV build of my 215 Hopper design is complete.

215H-FPV-7

The build wasn’t quite as smooth as I had hoped for a few of reasons:

  1. The new routing for the motor wires, through the arms, came up short. An extra 10mm or so and I would have run them as they were. As it is though I ended up extending the wires. This also made soldering them to the ESC’s a simpler task so it was a good move in the end. Despite the extra complexity in the build I am very pleased with how this aspect of the design turned out.
  2. My initial design for the base plate of the camera mount fouled on the zip ties that hold the ESC’s in place. I had to shorten that and print the new design.
  3. My initial design for the video transmitter carrier fouled on the heads of the screws  that mount the flight controller. This was actually 2 errors rolled into one. I absentmindedly assembled the frame back to front with respect to the flight controller. i.e. the flight controller is in the front half rather than the rear half. This doesnt make any difference flight wise but it would have meant the carrier wouldn’t have fitted up even if I had accounted for the flight controller screws.

The second failure with the video transmitter carrier design is also the same failure as with the camera mount. It is a lesson that I have learnt the hard way on to many occasions and it is thus; If you are using CAD use it fully, every detail should be represented in your model. If you leave something out, either intentionally or inadvertently it will come back to bite you at a later stage of the project. In the case of the camera mount I didn’t even have the holes for the zip ties let alone the zip ties themselves. For the transmitter carrier I didn’t have the screws in my model. Thankfully having the 3D printer on hand meant that I could correct these errors in the space of an evening and was ready to fly on saturday morning.

215H-FPV-8

With the new build came new batteries, I am now flying on 4S 1400mAh batteries (hobbyking) and loving it. I went with the higher discharge rate option, it is perhaps overkill but it means I get much further through the capacity of the battery before voltage sag starts hitting my warning levels.

215H-FPV-10

Other than the mentioned hiccups the build was much the same as the ‘base model’ 215 Hopper as I detailed here. I will put together a similar writeup for the FPV model in the near future. The design files will also be available. On top of that I now have a big stack of PCB’s for the build which I will make available for purchase. A full frame kit with hardware and 3D printed parts may also be an option.

215 Hopper FPV Build

After the mad rush of getting my ultimaker operational and making my Iron Man mask I have finally been able to get back to my FPV build of the 215 Hopper. I now have all the frame components made and there are some significant changes from the original.

215H-FPV-1

To start off with though, a tale of my first FPV session. As soon as I had all the pieces needed to fly FPV I had to try it. Knowing that my dedicated FPV build was still a couple of weeks away I rigged up the Hopper, mostly with cable ties and temporary wiring but also my first iteration of the camera mount/crash protection. The first couple of batteries were trouble free. Landings were rough but I was mostly taking things very easy, it was certainly a cool experience and all the gear performed flawlessly.

On the third battery I hit the ground quite heavily. Looking back at why I have realised that I basically flew it into the ground forgetting that maximum lift (i.e. quadcopter level) is going to be achieved with the camera pointing mostly towards to sky. When I came down I was looking mostly at the ground despite thinking I was pulling up. As can be seen below the airframe itself suffered no real damage. The motors all twisted on their tubes but that is easy to correct. Unfortunately one of the motors also came off its tube, the spinning prop cut one of its wires and pulled it out of the motor at the same time. The VTx also collected a lot of dirt given that it is exposed beneath the airframe. The roll hoop around the camera snapped as the quad tumbled, I guess this means it did its job of preventing the camera being a point of impact. All these factors combined meant that I decided not to fly with this cobbled together rig, I would wait until everything was in its proper place.215H-24

To address the wire cutting issue I have decided to route the wires through the tubes rather than hanging them loose around the arms. To achieve this I have had to redesign the motor mount. Previously the 2 parts of the motor mount and the motor were all clamped to the tube using the motor mounting bolts however the spacing meant that they could only just fit around the 12mm tube. This forces the wires to exit at 45° to the tube, in reality this would probably be fine but my sense of details told me to rotate them so the wires exit parallel with the tubes. To do this the new motor mounts incorporate their own M3 clamping bolts with captive nuts. To assemble them the top half of the tube clamp is bolted to the bottom of the motor (now using all 4 M2’s) before the two halves are clamped around the tube. The new mounts also include a slot on the end for passing the wires in to the tube.

215H-FPV-3

As mentioned in one of my design posts the rear motor mounts now also incorporate a small pocket for LED tail lights. I haven’t designed the tiny PCB for that yet but the image below shows where they will be with the power supply wires hanging out. I’ve been really impressed with the detail I have been able to model in to these parts. The wire grooves through the middle of these are only 1.5mm wide but are reproduced in perfectly useable fashion without needing to make any adjustments to my default print settings.

215H-FPV-6

At the rear the modified tube clamp for mounting the antenna has come up nicely but I may need to make a counter bore for the nut. The antenna itself is only just getting tight. All of the tube clamps are also modified on the inside with a hole for the motor wires to come through.

215H-FPV-4

Underneath I am very please with the VTx housing. I completed the details of its design after receiving my Lumenier TX5GPro Mini 600mW (GetFPV). It now sits inside the housing with no extra support required and is protected by thick ribs on the inside of the housing. The wires will be routed through the PCB rather than coming out the front as in the photo below.

215H-FPV-5

And finally the camera mount. There are a few pieces to the current solution but it allows for a lot of flexibility and feels much more robust than my first attempt. The camera is held in place by the clamping effect of the bolts in each side, it can be adjusted from 0° to 45° above horizontal.  To install it the base plate is attached to the airframe clamping the two posts in place before the threaded standoffs are inserted and each side of the housing is clamped around the camera.215H-FPV-7

I also decided that the less conspicuous look of black was better than a big red blob on the front.

215H-FPV-2

Next up is all the internals. I already have everything on hand so it won’t be too long before this is in the air.

215 Hopper FPV Details

Working from the concept layout for carrying FPV gear on the 215 Hopper which I wrote about previously I have developed a few new parts which can be 3D printed. I have come up with a camera bracket with an integrated ‘roll cage’. The camera angle is set with a 3D printed wedge behind it.

215H-25

On the bottom I have created something of a streamlined housing to go over the video transmitter. Of particular note in this area; when I dropped the model of the ImmersionRC transmitter in place I was quite surprised how large it actually was. As such I went looking for a smaller unit. I have consequently also picked up a Lumenier Tx5GPro mini 600mW TX (GetFPV). I will compare the two when they both arrive but suspect I will run the Lumenier rather the the IRC and as such that is what I have designed the pod to fit around. When I actually have the transmitter in front of me I will be able to flesh out the internal details of the pod so that the TX is a nice snap fit inside.

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215H-26

At the rear I have modified one of the central tube clamps to include a bracket for screwing the SMA 90° connector to. The antenna is then subsequently connected on top. Hopefully this provides enough support and isolation to prevent any damage to the transmitter in the event of an antenna strike. Also of note here is the addition of tail lights. As I can’t run the traditional WS2812b LED’s with the telemetry on a soft serial port these will just be on whenever the battery is connected. I am adding them for LOS flying visibility as much as anything. There have been a couple of occasions  with the 215 Hopper (including when I lost the first build) where I have struggled to orient the craft even at relatively close distances. The hope here is that with a few super bright LED’s pointing in one direction such problems will be easier to resolve.

215H-27

And finally, I have made a decision on goggles and decided to go with the FatShark Dominator V3 (NextFPV) running a NextWave race band module (NextFPV). I haven’t received them yet (only ordered yesterday) but will make some comments on them when I do. In the same order I picked up another Naze32 and a set of esc’s so I can build this ‘215 Hopper FPV’ up as a new a rig and keep the other one flyable.

215 Hopper FPV

Recently I flew with a couple of other pilots for the first time, one of whom had an FPV rig. As soon as he flew off in to the distance I knew that I had to get into FPV as soon as possible. So now I have bitten the bullet and started to put together and FPV kit. I haven’t purchased a set of goggles yet as there is some internal debate about starting at the cheap end with something like the Eachine VR-007 or spending the money upfront and getting the Fatshark Dominator V3’s. I’m currently leaning towards the latter option.

To get the ball rolling I’ve started off with the airborne end:

  • Camera – Foxeer HS1189 XAT1200M (NextFPV) – Primarily chosen for the 16:9 aspect ratio.
  • Transmitter – ImmersionRC Race Band 200mW 5.8GHz A/V Transmitter (Hobby King)
  • Antenna – ImmersionRC 5.8GHz Circular Polarized SpiroNet Antenna V2 (Hobby King)

To start with I will keep things as simple as possible so no OSD or any other extra bits, just this basic video system.

So far I have only received the camera, I am still waiting for my Hobby King order, however I decided I would start roughing out a layout to see how all the parts are going to fit onto the 215 Hopper platform. My progress can be seen below.  Obviously I need to design brackets and housings for the various parts but this shows how it might be laid out. To differentiate the FPV version I thought a colour change was in order (I’ve also just bought red filament, the orange will go go back to Steelcity Electronics before too long).

215H-24