Phantom 2 - Case Study

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Hi there. Below is a detailed description of my P2 rig. I don't offer this up as best practice or anything, but a case study of what I have done and some notes about my observations during the build and flying the rig. I fly on average twice a week - more during the summer, so have about 65 flights on the original battery and about the same on a newer genuine one I bought in September.

120htvm.jpg

My P2 was bought in May 2014, so has the original remote with slider on the back. Early on I replaced this with a separate control knob. This is a high quality 5K linear pot with a nice tactile knob on it, so I know where the control is. The R/C Tx is powered by Energiser Lithium Power AA batteries, which I found give more than 100 flights in my other R/C transmitters before requiring replacement. In fact, I am still on the first set in this TX!

The quad itself is a standard P2, with H3-3D V1 gimbal, GoPro Hero 3+ Black camera, Immersion 600mW or 25mW video transmitter iOSD Mini, TK102-2 tracker and taller and wider landing gear. The "prongs" on the front are cut down prop guards which are used purely for orientation purposes. The later, higher thrust propellers are fitted, which I find are quieter and give slightly longer running. Top speed is not much changed, at about 18M/s in still air, with up to 25 m/s with a good breeze.

I did initially fly with prop guards, but soon dispensed with them, as they are less of a help and more of a hindrance. I had one near crash due to VRS and found the reduction in top speed to be more of an issue than the possibility of hitting things.

On the ground side, I have a Flysight Black Pearl 8" monitor with diversity (twin) receivers. This is the 32 Channel version, which I gather some have had issues with when using with the Immersion TX, but I find the range is good with either TX that I have. This is mounted to the R/C TX with a simple bracket. It comes with a sun shade, which is invaluable in strong sunlight. I also have a cheap DVR velcro'd to the back of the monitor, recording via the AV output. I also have a 10" monitor I use for handing to anyone I am flying with, so they can see the video feed as well. This has its own receiver, so they are not tied to me.

As you can see, all wiring is external to the quadcopter, as is the mounting of the TX and iOSD Mini. This ensures it is easy to carry out updates and channel changes and also ensures good airflow around the TX as well. The underside of the quad is covered with female Velcro, so attaching and positioning equipment is easy and quick.

I did try a 2W video TX - a Chinese Boscam Thunderbolt copy, but discarded it, as not only is it illegal in the UK, the range was not a lot more than the Immersion during ground tests and the power consumption far higher, leading to a warmer flight battery and reduced flight times. Antennae are simple clover leaf, all the same polarisation, with a home made 6 turn helical if running the lower powered TX and working more than 300M or so away. In the UK, we are limited to 25mW for airborne video transmission, with only 5.8GHz available without a licence. This is very limited in terms of range, particularly with the Black Pearl monitor, which has fairly low sensitivity receivers.

I run the Go-Pro in medium view, at 30FPS 1080P. This makes upload to Youtube pretty seamless, but TBH, I fly more for my own pleasure than photographing or recording specific landmarks. I have however, recorded some old Cold War buildings on the airfield I work on, as they were due to be demolished and the recording group wanted some aerial shots of them.

The gimbal has been moved forward on a simple aluminium bracket. The bolts onto the front mounting holes, along with the gimbal bracket - which is simply turned around so that the rear holes can be used to bolt onto the quadcopter, with the front holes bolted to the bracket. A nylon safety bond runs from the camera to the bracket in case a hard crash causes separation. Cable ties are used to safety the gimbal itself - fixed loosely around the rear mounts. I am currently using the white anti-vibration mounts, as these seem to work well on my set up. The bracket is also mounted via rubber bushes to prevent vibration and high frequency flexing. Moving forward means the legs are less of an issue, as is prop shadow.

The TK102-2 tracker is also located onto the top of the bracket. This makes it very easy to get to its battery compartment as, these unit does not have an on / off switch. It is fixed with Velcro and a cable tie, so can be swung out of the way to get to the USB socket on the quad for updates. I use an o2 sim card, which is £8 per month for unlimited texts, so not expensive to run. It could be cheaper on a PAYG sim, but knowing me, I would forget to top it up... I also use the "Find My Tracker" app, which automates most of the communication with the tracker, meaning setting up and changing settings is as easy as pressing a button. No entering passwords and strings of numbers and characters to change settings. The tracker simply sends me a text if called, as well as if it senses a severe shock. It is accurate to 10M or so, provided GPS and mobile coverage is available.

I carry a bright orange case - good for spotting the landing point if flying quite high, which holds the radio control, spares, batteries, an anemometer (Wind speed meter) and also my paperwork, which includes flight check lists, operating instructions for all equipment and my liability insurance certificate. I also carry a VFR aviation map, which lists permanent restricted flying areas and other areas to avoid - like parachute clubs etc. The quad has its own fibre case with foam cut outs for the legs and gimbal.

I fly at work - an old USAF base in Cambridgeshire, where I have nearly 6000 acres of Cold War buildings, bunkers and runways to explore. I also fly across farmland closer to home, taking off from public footpaths and other rights of way. I avoid busier areas, or fly early in the morning when there is little chance of meeting too many people. I avoid flying over any structure and observe the CAA regulations and so far have not had any unpleasant run ins with any one, just the odd rubber necker who is interested in the hobby.

So, in more than 120 flights, I have never crashed, never had a fly away or loss of control. I had a dodgy TX from new, which had a failed gimbal tilt control and a weird intermittent IOC switch, but that's been all. I am quite a conservative flyer, limiting altitude to no more than 100M and usually staying within 400M of my start position. Quite honestly, I can't see the thing further out than this and never want to rely on the video link. I should also point out I have flown R/C helicopters for years, so have plenty of crashes in those! I tend to land on the flight case and only hand catch if it is windy enough to knock the quad over once it is on the ground. I use a glide slope into the wind, at about 5 m/s and aim to end up just above the flight case, before dropping the last few inches into land. This has taken me more practice than anything else, but is worth the effort when you get it right :)

Hopefully some people will find sections of this useful and will assist them in making decisions about how to fit out and tweak their quadcopter to give them the best experience :)
 
the velcro is a cool idea. I still think internally mounting the iOSD Mini is better though... there was only 1 firmware update ever so far and that was long ago... I think having all the cables up inside the body is better than having them dangling around where they could snag or anything... even just in transport or whatever.
but not trying to slag on your build or anything, it's way clean and if it works for you that's awesome.
I wish I had a cool place like that air base you mentioned to fly around!
 
Nice write up, thanks! - sounds like you have cool places to fly and explore - I need to find some... living in central florida - a lot of places look the same :)
 
Thanks for the replies. The cabling is all cable tied and cut to length, so not much to catch on. The only thing I did consider was moving the can bus from the leg, but have not got around to this as yet.
 

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