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Archive for February, 2012
Posted by KCV6 | Feb 29, 2012 @ 07:44 AM | 59,887 Views
I took the lower frame into work and tapped the holes in the rods to M5 rather than M4 and fitted long Nylon Bolts to the lower rods. The whole lower assembly is very strong now, even with the thin G-10 and doesnít need any CF doublers. If I land real hard and break them Iíll just make up some more.

I decided to use nylon bolts and nuts for fixing the dome, rather than using body clips and pins. The R clips can be a bit of a pain to locate so having to use a small flat blade and fingers to hold the bolt isnít inconvenient. The Hoverfly GPS compass doesn't like any thing that contains iron being within a couple of hundred mm so figured I'd dump the R clips. Almost all the frame fasteners are now Aluminum or Nylon. I will swap out the remaining A4 stainless bits when I strip it down to do the final wiring.

All my 4S packs fit the battery holders, 3000, 5000 and 8000. There is enough room to strap 4 packs (two each side with parallel cables) in.

I can already see the order for an extra 4 motors and speedies going in so I can convert this to a Coax X8. We shall see

I started work on a second tray that will simply have slots and allow packs to be fitted flush on in the tray. This can be swapped by simply un-doing 4 bolts, dropping the side mount frame out and fitting the flat tray. I need to get a few more frame parts made up to do this without having to slide the rods out of the grommets every time I want to swap. Obviously this will only work if it stays a Quad or I learn to do very precise bucket landings.

Speedies are in country so I should have them tomorrow or Friday, so fingers crossed it will be all wired up and ready for Maiden early next week.

The packs fitted in the pics are the 3000mAh 4S 40C Turnigy's
Posted by KCV6 | Feb 28, 2012 @ 08:47 AM | 60,138 Views
Finished cleaning up the parts I had cut the other day for the LiPo mounts. Could not find my M4 tap anywhere so went ahead and final assembled the lower tray. 2 of the small rods were already tapped. I will have to do the others at work tomorrow during morning tea break.

I added split rubber strips to the area where the LiPo gets strapped in. I did this on the Octo. This stops the LiPo from slipping around and the holder from denting the pack.

I'm thinking I might make up 4 1mm thk Carbon Fibre doublers to strengthed up the LiPo mount made from 1.5mm G-10. I will use the mount as the landing gear for now until I tune it all up and work out the best prop/LiPo combination. The doublers will be held in place by the bolts holding the small rods which should make it a bit stiffer. I may even CA them as well.
Posted by KCV6 | Feb 27, 2012 @ 07:42 AM | 59,877 Views
Got around to getting some more pieces together today. Droidworx use a really good system to connect the "payload/camera" to the underside of their platforms. It pretty much consists of a couple of carbon rods with threaded inserts and a U shaped base plate and a bunch of thru hole grommets. The grommets act as double vibration isolation and so long as the plate has some weight hanging off it it works very nicely.

I didn't have a spare plate so I got some 1.5mm Aluminum and fabricated my own. I had some grommets and fasteners that would do the job.

I also decided I wanted to mount my LiPo's off to the sides in the same manner Photohigher does with their retractable landing gear.

Below are some pics of the parts I got together and some basic assembly shots. There is an A4 sheet of paper with my first draft of what the 2 battery holder plates will look like. The last picture is a 3D model showing the LiPo Mounting plates and rods and how they mount. These get attached to the sides of the U shaped tray via passing the grommets through both the tray and the plate. I will try to get these cut and prepared over the next couple of days. Once thatís done I can attach the landing gear to these and then get to wiring the Quad up.

This Quad is actually coming together quite quickly. Having a lot of spare parts and some scrap CF laying around of course helps this
Posted by KCV6 | Feb 26, 2012 @ 10:12 AM | 59,829 Views
Didn't get much done on the Quad today, just fiddled and fettled what was already done. Fitted the pins for retaining the dome and bolted everything that is done together properly so I could measure between motors and the center of the frame to make sure it's all square. Good news it's all within millimeters so I'm pretty happy.

I did bend up a lower mounting plate from 1.6mm Aluminum and shaped it up and gave it a coat of flat black etch. I'll explain where this goes later. It's 1:30am so I'll take some pics tomorrow and add them here. This leads into making the LiPo mounts that allow the packs to be strapped either side. I'm copying the same sort of setup that was done on the Octo as it works really well.

This is definitely the most solid, free of any flex frame I have built up yet. I don't know if thatís going to be a good thing or a bad thing. If I have learnt anything from the Octo it would be that a bit of flex seems to be a good thing but then again it's AUW is very high so it's not like it's going to be doing zippy snappy moves. The Quad on the other hand may be a bit more zippy even with some weight on it. Time will tell.
Posted by KCV6 | Feb 25, 2012 @ 02:02 AM | 60,478 Views
I used some time during my breaks at work to model up in 3D the various bits and pieces so I could make up some custom center plates for my Droidworx bitsa.

I will add some 3D images later when I get a chance to save them off my PC at work. If you have access to CAD packages, even if they are only 2D, my advice is use them. It makes custom designing and changing things a whole lot easier.

The main partís I was missing amongst my Droidworx leftovers was the 2 center plates and the flight controller adapter plate. I wanted to incorporate half of the Octo crash cage that wasnít being used into this quad. I decided to change the layout of the center plates so they had four extensions that allowed the crash cage to bolt up to them to make it nice and rigid. This would add an extra set of boom braces to each boom.

I managed to get some 1.6mm thick copper clad (unfortunately) PCB substrate in sheets 600mm x 300mm. These came at the fantastic price of zero dollars (perhaps the copper cladding isn't so unfortunate ). These would be perfect as the crash cage is 300mm across at it's widest point. Best bit is it's woven epoxy glass (G-10) so it's a bit flexible but still nice and strong.

I designed up the 3D (ProE) models of the center plates and also the FC adapter board and confirmed everything fitted together. I then saved them as DXF files. I then used AutoCad to open the DXF files and convert all the holes and lines to 0.5mm thick pollylines and printed all...Continue Reading
Posted by KCV6 | Feb 23, 2012 @ 09:20 AM | 60,864 Views
Decided to split the build into sections:

This section will detail the booms motor mounting and wiring of ESC's so each boom can be unplugged and unbolted as a complete unit. I used this same approach on the Octo. While it means there are a lot of power connectors, wiring from the speedie to the motors is hard wired.

I decided that a motor spacing of 800mm would be a good starting point so I cut 4 spare 500mm 20mm diameter carbon booms back to 400mm being careful to cut from the existing motor end so the through holes used by the inner boom mounts were left.

I drilled and tapped out the motor mounting holes to M4. These are spaced at 25mm. The SK 3548 970Kv motors come with M3 mounting holes standard.

Rather than buy or fabricate round motor mount blocks I decided I would use the spare boom mounts from an un-used crash cage in conjunction with the standard heavylift mounting plates from Droidworx. The hole spacing on the boom clamps is 26mm so I decided to drill them out to 5mm to make for a tight fit. The slotted motor mount plate was then screwed to the base of the motor with 2 x CSK M4 fasteners and longer M4 cap heads would be used to hold the motors and plate to the boom clamps. This worked out quite well and there is no flex at all in the motor clamping to the boom. The Long M4 bolts thread into the motor end by about 1D (4mm) so this should be enough thread to make for reliable mechanical strength.

I will probably purchase some new mounts once I...Continue Reading
Posted by KCV6 | Feb 23, 2012 @ 08:56 AM | 60,356 Views
Decided I'd start a build log on my latest multirotor.

I had a lot of spare Droidworx bits left over from the build of our Droidworx SkyJib 8 last year. The Big Octo is problematic in getting it out regularly to fly for several reasons. When being used for work it's classified as a UAS and requires a certified UAS operator and even when it isnít being used for work it is awkward to transport in one piece.

Anyway I happen to have a bunch of Droidworx bits and pieces spare. The main parts I am missing are the center plates and motor mounts. I figured I would 3D model up my own plates to accept the 20mm diameter booms and boom holders I had and make the mounts out of boom holders and the spare coax plates I had. I could always invest in 4 coax mounts later and convert this frame into a CX4. I also have a full set of fixed extended landing gear spare. I'm not sure if I will use these or make up a new shorter set as this Quad is more for fun and possibly to do some training with for some of the guys I work with.

Anyway I guess the first decision was what motors and props to run. Once I sorted this out I could make a decision on what length to cut the spare 500mm booms back to. I decided to use Turnigy 3548 970Kv motors (I had a couple already) spinning APC 14"x4.7" SF props. This made sense as the Octo was already using these props and I had plenty of 4S LiPos which would power these motors fine.

Next choice was to pick ESCís. I had a spare Plush...Continue Reading