350 Hammerhead H (Genesis of the)

[flybywire]

Owing to a temporary cease in tech support ';hostilities'; at work, I';ve had a measure of time to concentrate on a new 350 H frame design, my first such frame!
It';s primary purpose will be fast but steady fpv/video recording utilising small 2500 mAh 4 cell lipo';s a CC3D and a set of Micro Titan motors swinging 6" props.
So, I';ve managed to work through things, and produce a cardboard prototype, just to get a feel for the frame, and whether it';ll be fit for purpose or not.
As I was at work at the time, I had to use Google as my best friend, and obtain measurements for all the various components, and as I assembled the mockup earlier this evening, it became clear that a few of these will need some alteration!

The drawings pictured here were the first draft, I realised that I would need more space to mount the 20a Afro';s along the body, so I elongated it a tad.






I envisage the arms being composed 10mm carbon box profile, with holes to carry the motor wires out to the motors for protection and neatness.

Video Tx will reside to the rear as normal, and I have an idea that the lipo will fit underneath.  I think carbon would be preferable, but I may just stick to Delrin, at least for the flying prototype at any rate.

I took a load more pics, lord knows where they went, I have the camera equivalent of the Bermuda triangle!

Later';s!

[nub]

looks good flyby can';t wait to see her in the air!

[flybywire]

looks good flyby can';t wait to see her in the air!

Cheers nub, yeah, i';m hoping it';ll hang together!

[flybywire]

Day two:
Adjusted apertures for ancillary gear, widened bottom 2mm plate to take 20a Afro';s side by side, added FC central riser to allow central placement for two sizes of 4 cell ZC lipo';s (2200 & 2700). 
Note to self: make hole to insert HK retrieval buzzer!

I';m liking it, as i say, i';ve never had an H frame before, so it feels slightly strange to me, but also strangely familiar, and highly practical in terms of avoiding props in view etc.



The two oblong shapes represent the Zippy Compact';s i';ll likely be using to throw this beast as fast and as low as i can get!

I';ve ordered a shitfer of ally standoffs (for this and other projects) 10mm square carbon tube for arms, Delrin, Micro Titan motors, diatone props by the case, gawd knows what else, they may show up on the spreadsheet as ';kitchen accessories';.  Ahem..

Tomorrow, i';ll cut another cardboard mockup, as it costs nowt, bolt it together, and if it looks decent then the next cut will be the actual Delrin, when it arrives.
I';ve been eyeing up lasers on t';internet, they really have come down in price, to give you some idea, ours, a 30 watt Denford Versa Laser was purchased about 5 years ago for the not unconciderable sum of c.£5000, i';ve seen a reasonably decent looking 50 watt with enclosure ready for extraction fitting for about£1200. Not exactly a king';s ransome when you consider what they can cut.
I';d really want it to cut at least G10 tho, so not sure how practical that is?  It claims to cut up to 10mm Acetal/Delrin.

[flybywire]

Day 3.
Managed to sort a few things out, like squaring up the FC & PDB mounting holes/ lightening holes symmetrically, discovered a real easy way to do this, by drawing a square of the same size as the mounting holes using the step lock function, then two diagonals, snapping to intersections.  then I attached 4 holes of 3mm dia, again attaching to the corner intersections, then the neat trick; selecting the contour tool, I clicked on each diagonal in turn which inserted a symmetrical equilateral triangle.  The first attempt I had the gap set too large, so I lowered it to 2mm, and bingo!  Then, I added the radius to the corners, deleted the guide lines.  Easier than it sounds, maybe not the definitive way, but I';m just learning this stuff as I go along, but it seemed logical!







There always seems to be something to modify, like the lens holder clearance on the front of the middle plate, missed a hole out to at the rear to secure the rear carbon arm, oh and a few more lightening holes and cable routing holes as well.  I';ll also modify the bottom plate sides, as I prefer it to mimic the contour of the middle plate, but still have enough width to support the ESC';s.
Plus..I will need to increase the height of the 25mm standoffs for the FC deck, maybe to 30mm for better lipo clearance.

The motor mounts (which are pretty simple) have hole spacing';s for the Micro Titan 2204 motors, and will likely be mounted on the underside of the arms.  I';m also going to redesign the fpv board cam mount, so it bolts on to a small plate, as is usually the way.

Maybe I';ll get hold of the Delrin tomoz, in which case, if I';ve satisfied myself that all the mods check out, I';ll try a cut, then throw it all together.  The ally standoffs are winging their way across the South China sea I believe.
Oh, and that carbon tube from Carbon Mods is massively strong, much stronger than I';d surmised in fact.
NB. UPS apparently managed to damage the first one, gawd knows how, must have driven the van over it!

[flybywire]

Day 4

Well, I';ve had my head in this thing for so long now, I';m starting to see everything in geometric shapes, or at least how I would represent them in the CAD software at any rate.   

But, and it';s a big but, I feel that like everything in this life, you get nowhere if you quit early.  Of course, you do need to have some kind of plan or end game, which I think I do have in this project at least.
Hey ho!  the air was thick with burning card earlier on (yes, I forgot to turn the laser extraction on for about 30 secs!) 


What';s cookin';? 





Ah well, post image has defeated my will to live yet again, oh for a reliable web host 

I';m so much happier with the board cam mounting now, much more swish, I just really need to add the odd cable aperture and a couple of lightening holes in the centre 4mm plate, plus the alarm mounting hole and it';s job done.
Can';t wait for this li';l bird to roast...ugh soz! 

No Delrin as yet, never mind, patience is a virtue, or maybe more a necessity with RM!



Ohh, bonus pic!
Shakin'; that ass...




P.s, i';m wondering how i can incorporate a Banksy on the rear deck.. There is room.
Oh, yes, i think it';s taking on a Gothic twist, hark! The sisters of mercy!

[richardg6paj]

Hi Andy,
Long time no speak! I';ve been busy just lately (just bought myself a new large motorcycle, tests have to be passed before I';m allowed to kill myself),, but have been following your new design, looking good and nice to see that you are getting to grips with cad. I do like the cardboard prototype. If you move to plywood you will also be able to fly it. I see one weakness on the bottom plate and that is across the ESC holes, if you draw an imaginary line across the zip tie holes you';ll see there isn';t a lot of material holding it together. Yes, I do realise that the top plate will add some strength. So why not fill the ESC holes in with a cross like the pdb area at the centre of the plate. That should give it a little more strength. Just sayin';.


Richard

[flybywire]

Hi Andy,
Long time no speak! I';ve been busy just lately (just bought myself a new large motorcycle, tests have to be passed before I';m allowed to kill myself),, but have been following your new design, looking good and nice to see that you are getting to grips with cad. I do like the cardboard prototype. If you move to plywood you will also be able to fly it. I see one weakness on the bottom plate and that is across the ESC holes, if you draw an imaginary line across the zip tie holes you';ll see there isn';t a lot of material holding it together. Yes, I do realise that the top plate will add some strength. So why not fill the ESC holes in with a cross like the pdb area at the centre of the plate. That should give it a little more strength. Just sayin';.


Richard

Howdy Rich, that';s cool about your bike, i passed my bike test back in the late 70';s, good on yer!

Thanks for the constructive, i totally agree with you on this, hadn';t really thought about the strength aspect of the bottom plate, as it is just really to strap the power bits to, but yes, a cross would make more sense, without affecting the weight at all.
My centre plate will be 4mm delrin, which will hopefully tie it all together, and i was genuinely surprised at how strong the 10mm carbon sq tube is across the whole 1 metre length i bought. 
I did wonder where you';d gone!

If i had some dosh to spare, i';d certainly invest in a 50w laser cutter, they are so versatile.  I have used card as it';s free, and although i can';t yet figure out translating my designs to orthographic projections, even if i could ( which would be nice) you can';t fit stuff together on a computer, but he, Windows 10 anyone? (I';m thinking holograms here)

Cheers

Andy

[flybywire]

Today, I made some in-roads into my 350 project, by managing to cut the frame parts totally myself, sans intervention/assistance, flying solo so to speak, and to my surprise, I managed to get the job done.
I made a mistake in the first pass of the laser for the 4mm, as I opted to use the Delrin setting, input the material thickness, and pressed go.  It went through the motions, but failed to cut to any real depth, so I reverted to the acrylic setting for perspex and the like, and ran it for a second pass.  This time it cut pretty much straight through, although I did run it again, as I';d prefer it to fall out rather than to resort to bending & twisting.
Then I positioned the 2mm sheet, and highlighted the parts to be cut from the file, and pressed the start button.
This went much better, and the first cut dropped straight through, result!
First up, the kit of parts:
I could imagine getting this as a kid, eagerly pushing it out from the plastic sprue!  Whoops b****!
Looking at it further, i think the middle plate and the motor mounts could be cut from 3mm, as the 4mm is overkill.  I have some black 3mm kicking around, as i may have cut the motor holes too large, not sure until they get here!


Easy peasy!  Really pleased how it goes together, with my new ally standoffs.  To my shame, I have neglected to order up the m3x25 bolts, so its plastic for now I';m afraid!



Where does this bit go dad?



It';s my ';cunning plan';, I';m calling it the ';jock strap'; or ';bone bar';, see for yourself:
Also, you can see the buzzer held in the top plate.  There is room for a slither of foam under the GoPro.


No m2 bolts either!  Bother!


I even managed the Banksy, "is not hampster, is rat Mr Fawlty"!


A bit clearer here...


It';s time to order up some more fastenings, sizes that I can use on all my builds, past & future, as I think on balance, plastic causes less damage, but is frustrating sometimes, as they do sheer at the drop of a hat.
Titanium is the way to go I think.

P.S Big up for Postimage tonight, it';s flying!  Must have heard me moaning t';other day, maybe.

Almost forgot!  Ordered up some opto 20a Afro';s, i notice the firmware includes one shot for larks.  Save me the job of jiggering them if mowt else!

[flybywire]

Talking of fasteners, I';m really starting to dither with all the options.  Let me explain.  My Wasp 250 original design, pretty much followed the tried and tested separate arms design, which is fine and obviously more crash resistant in theory to the integral frame, and I used plastic bolts/standoffs/spacers. This was ok-ish, but crash wise, anything harder than a lumpy landing resulted in one or more sheared bolts, and lost spacers.  Not the end of the world, but annoying none the less.

So, I redesigned it with a completely new integral frame, still using plastic bolts/nuts/spacers for the construction.  I haven';t had time to fly either of the two frames I';ve built yet, due to other more pressing engagements, but twisting it around in my hands/throwing it around the room has not yet yielded any serious deconstruction.
Now, with this larger 250 build, I figured metal fixings would be king, but I';m having serious second thoughts, and maybe, just maybe, the plastic fittings may suffice after all.

Hmmm...   Decisions decisions.....

[flybywire]

Once you get this design bug, it keeps gnawing away, everytime I fire up the software, I see another mod waiting to be made!     Maybe it';s called evolution?  I don';t know.

So the other day, I was looking more closely at the motor mounts, and I decided that A: they were too short to be useful, and B: I didn';t like the idea of drilling the carbon at the ends, or the fact that the bolts would hinder the passage of the wires.  Plus....I received my 4 Airbots today, so wasted no time in eyeing them up for a fit.  They look really nice, and have no protruding shaft from the underside like many motors you can buy.  THey also have dual mounting holes for direct mount props or prop nut/spinner (supplied).  Anyhow, I digress, so I knocked up a little design for the new motor mounts, and cut them from some 3mm delrin I had from an offcut.  I also cut another top deck from 2mm, with a modified cam mount, as I feel the original one was over the top.
When it';s all bolted together, it';ll be strong enough to survive all but the worst of smack-up';s!

I have a bag of bolts coming from HK UK, so should be here in a day or so, can';t wait to get things bolted together.

New motor mount...


Avante!

Edit: I';m wondering if I can get a little dampening material between the top and bottom plates here, might be useful..

[atomiclama]

That';s neat.

How about tie wraps instead of the bolts as the weak link to break first.

[flybywire]

That';s neat.

How about tie wraps instead of the bolts as the weak link to break first.

Ta Atomic!  Yes, i was musing about the old zip ties earlier on, not sure if they';ll be strong enough, but i';ll definitely give ';em a try.

[richardg6paj]

Hi Andy still evolving! I also thought zip ties for motor mounts and for fixing the cf arms to the main frame. You could use the 4mm zips for extra strength.

Keep at it. It';s looking good. I don';t have any delrin to try, does it break when bent to the extreme or does it just bend.

Richard.

[flybywire]

Hi Andy still evolving! I also thought zip ties for motor mounts and for fixing the cf arms to the main frame. You could use the 4mm zips for extra strength.

Keep at it. It';s looking good. I don';t have any delrin to try, does it break when bent to the extreme or does it just bend.

Richard.

It sure does Rich!     I just tried bending some 3mm, it';s very tough, just about managed to bend it round on itself without breaking, then it just springs back with very little distortion.  I believe they make the buckles on rucksacks from the stuff.

Oh yes, some ';news'; from my workplace, apparently they are spending the £1000 necessary to ';re-gas'; the laser, so I might be cutting G10 later in the year.    

[richardg6paj]

Hi Andy,
Thanks for the info, yes buckles etc. are made from delrin very tough, I wasn';t sure if it eventually broke when bent to the extreme. I can only get 6mm locally but still looking.

From what I';ve heard/read G10 will not acceptably cut on a laser, requires a huge amount of power and the end result is not good with deep charring/burning of the cut edges. Due to the glass content obviously. Stick with Delrin or buy a cnc miller/router.

Richard

[flybywire]

Hi Andy,
Thanks for the info, yes buckles etc. are made from delrin very tough, I wasn';t sure if it eventually broke when bent to the extreme. I can only get 6mm locally but still looking.

From what I';ve heard/read G10 will not acceptably cut on a laser, requires a huge amount of power and the end result is not good with deep charring/burning of the cut edges. Due to the glass content obviously. Stick with Delrin or buy a cnc miller/router.

Richard

That';s not so good!  I did try a while ago, it got about half way through a piece of 2mm, seemed ok on the edge tho, we';ll see.   

[flybywire]

Well, I gave the ties my best shot, but TBH, I wasn';t happy with the result, I even rejigged the design a little to facilitate the use of 4mm ties, but couldn';t really get the positive lock of the motor mount assembly that I wanted. 

Coincidentally, my HK UK order had just arrived (mmm, nuts bolts and lovely Afro';s complete with one-shot), so I wasted no time in throwing in the 3mm bolts, each with a corresponding 3mm Nyloc.  Then Dremelled off the ';chaff';.




Superb!  they work a treat.  They have the added ability to be adjusted too, and TBH the extra weight will make little difference to the overall scheme of things.




Next:  I need to cut the carbon arms, I figured on 250mm, which would give a wheelbase of just under 350, I think!  Basically, I simply slide it along and see what ';looks'; right, then it usually is!  (A highly technical process of course).   

Then: Lord give me time to finish some stuff off! 

I made such a good job of the oak flooring in the kitchen (apparently) that Mrs FBW now insists on having the lounge done too!  Urgh!  rearrange the following words:

Rod>One';s>Making>For>a>Back...