DIY Expansion on the cheap!

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So we've all been there. Paid out a shed load of cash for the Phantom, got the extra battery, gone the FPV route and wanting more more more!! First thing that stumps us is expansion space and the fact we are now broke and on the brink of being thrown out of the house by the Missus 'If I see another parcel for that **** flying thing!!'

So this is what I did to get a bit more real-estate to use for FPV and/Or battery.

First thing I bourght on a bit of a punt were some M3 30mm male-female nylon hex spacers. The thinking would be that these replace the innermost screws on the landing legs (knowing there are nice safe brass threads into the body). £2.50 for 4 and super lightweight.



Next up was a 'tray' that would screw onto this. Carbon Fibre was the ideal solution but I am an impatient man when it comes to building stuff and having seen the spaces in place I didn't want to wait. So I looked around the garage and found an old tuppawear plastic sandwich box. Now as soon as I saw this I thought great... it is fairly light, flexes well and also its see-through so measuring for holes becomes a simple case of using a CD pen!

So this was cut to shape around the GoPro and stock mount....



First problem. The spacers are a little too high at 30mm and it means you can't undo the ally mounting screw on the GoPro mount.
Second issue and much more of a concern was the Nylon the spacers are made of. Very light but the threads themselves are made of nylon too so when tightening 2 of the threads stripped slightly. Way too risky to rely on in flight especially if a heavy gust hits the tray.
So these were dumped and replaced by 25mm versions in Brass. 12grams total weight for 4 of them so not bad really and they are all metal so no fear at all of the threads or body snapping when 'up there'.



Metal spacers are a lot more secure and will eventually have a spot of thread lock.



Next mod was to fit the Fat Shark Predator V2 TX. Now this is a lumpy little bugger and while I know many have used just sticky velcro to mount it with no ill effects, I wanted a nice flat base.

I've shown this in another thread but basically I used some balsa wood from an old canal boat model kit by late father had laying around in the garage. Calved it out with a dremel....



Less than a gram of weight!....



TX slots in nicely....



Then taped with the DJI fabric tape (avoiding covering the scorching hot TX itself)....



Then secured it further with ever faithful ductape to give a nice smooth 'non wooden' base...Tight and safe.



Then the velcro onto the ductape for a firm flat sticky surface.



I pulled the rubber grommet from the AUX power leg (no need to open the body doing this) and then used a connecting block which I have fabric taped to the legs. This allows me to vary the use of the AUX output if I ever get a gimbal or want extra lights.



Future plans may well include a Futaba T8J so I can do some distance FPV. Problem I see is battery life is an issue for that (how far can you get in 8 mins!). This rig 'should' allow me to secure an extra battery to the underside with no problems but the weight of 2 batts ontop of Fatshark, Garmin GTU10 and protected Hero3 will put me over the 1.2kg limit. Swapping out the Hero Skeleton housing for the DJI mount will get me JUST under but to be really safe I wanted the option to take the GoPro out and use the Fatshark Predator camera. This of course won't get me great recording quality but for fun it should allow me about 12 mins (if you believe reports).

Issue with the Fatshark Cam is the same as the TX... too **** lumpy at the back! So I did the same thing and routed out some balsa....



Dressed it in Ductape...



Secured the cam in its place. A nice flat, smooth back ready for a bigger surface area of velcro!



Next was mounting options for the camera. The battery cover is the obvious place for a front end mount but sitting flush the camera will point up. Not the end of the world but the option to look down would be good. Out comes the balsa again (the top of the canal boat model it would seem!)...



Wrapped with tape and velcro'd up....



The results?.... A 'straight forward' option (using the velcro to dampen it and point it down slightly).



A 45 degree downward looking option....



Come Monday I should receive an A4 sheet of 2mm rigid carbon so I can then use the plastic rig as a template and loose a bit more weight (and make it look posh too!). Sadly a little too windy at the moment for a decent test but maybe tomorrow.

I know its not exactly rocket science and I've seen plenty of other peoples mods that both look better and function as good but I thought I'd share this just to show what can be done for very little indeed.
 
It all looks great! Can't wait to see the video from this setup.
 
Thanks guys! I can't wait either!

Only had the Fatshark since Tuesday and still not had my first proper FPV flight. I could have fudged something together but better to make things secure first I felt. 15mph winds here today and while I know it will fly in this I am quite concious of the tray catching the wind.... something I may need to work on as you can see here:



Loads of 'gripping' space but I think i need to vent it a little more or it will turn into a mini sail!
 
Impressive Dremel skills! You have obviously noticed that the Fatshark Tx gets really hot - why dont they put a proper heatsink on those things?
 
howardmaryon said:
Impressive Dremel skills! You have obviously noticed that the Fatshark Tx gets really hot - why dont they put a proper heatsink on those things?

Thank you kindly! I forgot how fun and easy Balsa wood is to work with!! Cost and weight in that order i'd guess is the reason for a lack of heatsink. I think they also assume air flow will be present when in use maybe but christ it gets hot when static.

Still it'd be no fun if you didn't have to tinker a bit ;-)
 
simensays said:
It's great to see this kind of customizing work!
Great job, and keep it up!

Thanks Simon. I think the expansion tray, tx and cam housings will be a good project to get me back into 3D modelling again too. It'll turn the cheap project into an expensive one but who knows maybe others will buy them on Shapeways and fit the bill! :lol:
 
So the wind wasn't much better today (about 13-15mph) but I did get out to test it. Now bear in mind this is my first ever real FPV flight so it was a big learning curve having 'eyes in' rather than 'eyes on'! Things for me to remember next time:
1) point the GoPro down 30 to 45 degrees (the mount for the Fatshark cam will work well for this!)
2) Narrow mode isn't ideal especially with the cam pointing forward

As for the extension tray, well that performed ok under the conditions.

I have my concerns though from the footage as the phantom was listing when hovering. I don't have a propper balancer (yet) and i'm using pretty beaten blades so that might be the reason. Still a calm day will tell if I have a balance issue.
Everying is mounted down the centre apart from the TX filter (like 3grams?) so I don't think it is the tray.

For what it is worth this is the raw flight footage... shocking Jello (again suggesting balancing or new props badly needed), forgot to mute the sound blah blah. Still the Fatshark worked a treat and I had a spotter next to me watching the output of the goggles on my Macbook (via the aux out cable and a cheap capture card).

I was hoping the GTU10 history would tell me the altitude of the flight (I really want to know what 400feet looks/feels like for safety). Sadly it only tells you altitude when you live track it so that is a test for another day. I have nooo idea how reliable it is but it says i'm a static 60m above see level at the moment so as long as I hover 'up there' long enough it will be better than not knowing!

http://youtu.be/Dz-O1zdI58M

One other thing that interested me was the batt warning was on after landing. This was about 6 mins tops in air maybe. I'm not going to read too much into this due to the high(ish) winds but I will compare at somepoint flying with Fatshark on and with it off to see what real world affect it has on flight time.

This week the Carbon sheet will arrive and be cut to shape. If i get a calm dry day I will get out again with the second set of supplied (stock) props, re-calibrate the IMU and the compass. That should let me see how stable the setup is before the carbon version is fitted.

I'm also modelling it in 3D soon to see how much it will come out for on Shapeways. If it works out reasonable i have some ideas for the next steps and who knows some people might want one ;-)
 
So yesterday (with a hangover) I managed to replace my 'sandwich container' tray with carbon fibre cut from a rigid carbon sheet purchased from CarbonMods on ebay for £10.
Not as hard as I thought it could be to cut with a dremel but certainly needed my painting mask as the fumes were pretty bad!

Outcome looks good from the underside:




Things I have learnt:

1) 2mm is too thick. 1mm would have been 100% fine and this tray in its current form is 15 grams heavier than the sandwich box (plus there is less surface area!). Even at 1mm then this wouldn’t have been much lighter (if lighter at all) than the clear plastic. There is a lot less flex in the carbon of course although it wasn't a major issue before.

2) The rigid sheet is not laminated on both sides. This was my fault for being a cheap ***. Carbon Mods sell A4 double sided on their website for £53. I found this on Carbon Mods' own ebay shop for £10 but it turns out all their ebay stock appears to be single sided. Still it serves purpose. Rather alarming is the fact the same single sided sheet on their actual website retails at £25.48. I could understand them more than doubling the price if what I recieved was of poor quality but it really isn't some dodgey off cut so if people read this and want a bargain I'd strongly advise emailing them and asking for an Ebay price!

The idea of this mod was to fill a gap until my Shapeways custom design (http://www.phantompilots.com/viewtopic.php?f=4&t=999)arrived. Ironically UPS just emailed me to say that it might be with me early (like tomorrow). If my measurements are ok on the model then this mod will come off and be put in the 'test' bin. Frankly as its heavier than the plastic it will be going anyway! Live, learn and have fun in the meantime I say.
 

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