Boom Quad

[SheppO]

So here's a rough design for a 5" alien style quad but using the RCexplorer booms and motor mounts. CNC is pretty expensive so with the aim of realising a design I've turned to the boom option and cutting the 3 simple plate parts out by hand. Holes will be drilled to lighten the plates strategically and allow fixing points for kit.

 

[jipp]

cool. good luck on your build.. what are you gonna prototype it out of? some hobby grade plywood? probably would be the easiest.

chris.

 

[Darkback2]

I'm wondering a couple of things...but in looking at this I was thinking you could change the profile of the booms to reduce vertical drag. There have been a couple threads about that idea so that you basically reduce the amount of turbulent air created by the air from the props passing over the booms.

DB

 

[Snarls]

Looks like a cool DIY build. Not a lot of people scratch build frames anymore so it's always refreshing to see someone doing so.

 

[jipp]

I'm wondering a couple of things...but in looking at this I was thinking you could change the profile of the booms to reduce vertical drag. There have been a couple threads about that idea so that you basically reduce the amount of turbulent air created by the air from the props passing over the booms.

DB

im assuming he is using that arm setup because he is using davids tricopter folding arms.. so this will be a quad that folds up for easy transport.. on a crash the arms just fold back etc.

chris.

 

[SheppO]

Hey guys thanks for the comments. The rcExplorer booms and mounts are very cost effective considering their quality - shipping is cheap to the uk and will only require a little cutting to length . They have a hole pre drilled so this will be used as a main fixing point as per David's mini tri copter. I was not planning on these folding - but it could be an option. Remains to be seen how nicely I will be able to cut the plates but the shapes are pretty simple.

 

[Darkback2]

So a trick that I follow when cutting out things like this, Print out your cadd files on paper, then use rubber cement to glue the paper down on the material you are cutting. You can even use the cadd software to center mark the holes. Just make sure to cut well outside of the lines and then sand the material down to the line. Either center punch your holes, or drill them out really carefully with the hole centers marked. I've had parts come out pretty well close to perfect that way.

Best of luck to you!

DB

 

[SheppO]

So a trick that I follow when cutting out things like this, Print out your cadd files on paper, then use rubber cement to glue the paper down on the material you are cutting. You can even use the cadd software to center mark the holes. Just make sure to cut well outside of the lines and then sand the material down to the line. Either center punch your holes, or drill them out really carefully with the hole centers marked. I've had parts come out pretty well close to perfect that way.

Best of luck to you!

DB

Thanks DB - still weighing up whether to go for black G10/FR4 or 3k Carbon - all 2mm sheet (although the top plate could be 1.5mm). G10 is easier/cheaper/quicker to source here. Carbon would be lighter, and y'know....cooler. Anyone know if Carbon is harder to work with ?

 

[Darkback2]

Carbon is pretty easy to work with except for the dust. First time I worked with carbon I cut out a bunch of plates with just a dust mask and face shield. That stuff gets into your skin in a bad way. I ended up driving over to a friend's house that is close to work and taking a shower while they washed my clothes. (I live about 45 minutes away.)

At work we have a pretty good ventilation system now and a vacuum tube that sits right behind the bandsaw blade. That helps a lot. We also upgraded our face masks. The carbon fiber dulled the blades of our band saws pretty quickly, and while I haven't loaded any into the CNC I imagine you would be replacing tools pretty quickly also.

I do have a friend with access to a water jet...Not sure how that would turn out.

I found that buying 1 sheet of one thickness was the cheapest way, and planned out my cuts so that there wasn't much in the way of waste.

Another option is using a company like Big Blue Saw. The biggest hurdle there is the first cut. The setup fees are pretty onerous...After that the price per unit drops way down.

Final option is to use a hand saw and cut the whole thing out under running water. This would be good because you wouldn't have as much dust getting out into the air and your lungs, and your skin.

Hope this helps...

DB

 

[Snarls]

I like the water method with carbon, although it can be hard to work underwater. When cutting a notch in the front of my ZMR to better fit the camera I used a soaking wet paper towel next to my cutting copping saw. The wet towel caught all the dust in a sinister black muck. Still wear a mask and gloves though.

You might not want to work with carbon as this is your first build of this design and carbon is expensive. You could try G10 or even polycarbonate.

 

[SheppO]

Cool - so I took the plunge and ordered some materials and components for the frame - the booms are on back order but I'm in no great rush. One issue I identified last night is with the stack in the centre. The boom is 10mm plus 2mm clamping plate. To keep the frame as close to the Pythagorean x of the alien I am using the pre drilled boom end holes aligned to the FC hole spacing. I was planning to run a long m3 bolt through the boom and clamp plate and then add a nylock to hold all tight - the pdb would then sit on the nylock with a nylon spacer standoff on top to take the FC. But....i will have an issue here with conduction in the carbon booms / steel screws/ nylock into the pdb right ? Alternative would be to use a bind nut into the clamp plate to save height and then go for 5mm nylon standoffs to make a typical isolated pdb/FC stack. Or skip that and do a wiring loom following somas warp quad build vid eradicating a pdb all together. This will work as long as I follow the RRiot build spec and use the immersion vtx / camera powered off the Kiss. Hmmm...

 

[SheppO]

err... Vtx powered from the loom not the kiss - idiot

 

[SheppO]

So I found Armattan Productions and got some costs from China - turns out CNC is affordable this way. I dropped the boom idea, fired up CAD and here's the 5" frame I came up with. And yeah its pretty much an Alien / QAV-R blend and yes it will be a little more expensive than a Martian II - but Meh. Ordered 18 days ago so hoping I might have it in a couple of weeks.