jhitesma's Danaus style thing?

[jhitesma]

(Note - this thread was originally part of the dRonin not no longer just for the brave thread...but doens't really have a lot of dRonin content and has kind of got involved enough I figured it would do well on it's own. Balu was kind enough to split the posts out for me. So it starts a little abruptly, and if there are any missing posts you'll have to refer back to that thread )

The problem is, I have a problem... WAY too many builds going on at the same time. Lost track of which FC I was working with. LOL. Femto has Mag but no Baro, and I also have a Flip32 F3 Omnibus Nano with Baro but no Mag.... LOL!

Bought the F3 Omnibus thinking it was supported by dRonin, but it appears that only the F4 omnibus is supported. D'OH!

Cheers!
LitterBug

I know how that can go. Airbot boards are so easy to get confused on since they have so many similarly named but not always compatible with their own prior revisions.

I'm finally thinking I'll do something with the parts from my angle quad. I cut/printed new parts for awhile back...but had a few issues with the print and just can't get excited about building it up again. The angle arms were a neat experiment - but not anything I really want to keep flying. So been debating what to do with the parts...and think I'm going to try and do a 5" owl inspired thing:



I haven't added a FPV cam mount or all the standoffs yet...but coming together. Won't be super high performance...5" props so somewhat bigger than an actual owl. And not sure what I'm going to cut it out of yet. Debating between ply and lexan. I have ply on hand so it will probably win out...but lexan would look cool. With the weather finally getting close to tolerable outside I need to get something together and back in the air

May need to strip down my NHP280 and re-use it's motors on something with a newer FC as well...think I've still got four KISS esc's sitting around I could use on it. Then again I also have a set of brand new racerstar 2205's that have been sitting here for almost a year waiting for me to do something with them....And I need to finish wiring up my FT Explorer with a seppuku for testing fixed wing stuff....too many projects!

 

[LitterBug]

I have two Shen Drones Danaus 5" frames. They predate the owl and have the same protected prop design. It is actually designed around the QAV250 center section.


My first one has an SPRF3 in it, which as you know is not dRonin friendly. Still trying to decide what motors to put in the second frame, and will go with something more dRonin friendly. Prolly ought to find a SPRF3Evo to update the first one too.

Planning on dRonin-ifying two FPV planks really soon. Going to throw a DTFc in a RMRC Mako flying wing, and my BetaSeppuku in either my RMRC Surfer 1500 or 2000mm.



Mako is in the center above pic. Surfer 2000 is on the right. Surfer 1500 not pictured. Thinking the surfer 1500 will be a better candidate as I have an auxiliary shelf the would hold the FC and other gear in a really nice way.

Cheers!
LitterBug

 

[jhitesma]

I have two Shen Drones Danaus 5" frames. They predate the owl and have the same protected prop design. It is actually designed around the QAV250 center section.

Ah...I knew I had a seen a 5" setup like that from you but couldn't remember what it was I'm just looking for quick and dirty right now...eventually I'd like to cut it out of CF and make it light and more crash proof. But for now I'm more about cheap and easy to get some of these parts back in the air. If I had CF sheet on hand I'd probably do it in that after a quick
mockup...but I don't have any CF sheet or any budget for any right now so <shrug>

My first one has an SPRF3 in it, which as you know is not dRonin friendly. Still trying to decide what motors to put in the second frame, and will go with something more dRonin friendly. Prolly ought to find a SPRF3Evo to update the first one too.

This currently is wired up with a DTFc so that's what I'll be sticking with for now. Though I will probably add in a microminum for OSD...and if I find I enjoy flying it might consider swapping to a seppuku (I still have one that I haven't decided what to do with yet.) Heck I also have my OG brain in my old knuckle quad that's slowly being stripped for parts on other projects. I had planned on using it to test GPS stuff on a quad...but the motors have seen too many crashes and it's got too many vibes now - so it's just wall decoration and the not too beat up motors are slowing finding their way into planks.

 

[LitterBug]

Actually, for Danaus #2, I ought to use all the gear that was going in to building a RMRC Hellbender204 V2 last fall before I got sidetracked by the Seppuku beta. Found that box of parts last night when I was looking for other stuff. (did I mention I have a problem??) Have an mPB V1, BrainFPV RE1, Baro board, ESCs, Motors, ETC... all ready to drop in. My AWK210 V1 RE1 is still my best all around quad but it would be even better without having to strap a runcam or GoPro on top. I've started an AWK210 V2 build with a mPB V2, Seppuku, and RunCam split so really have no need to build the Hellbender at this point.

EDIT: This will also still allow me to run BetaFlight and play with 3D mode.....

 

[jhitesma]

You should touch base with icee - apparently he's setting up a Surfer for GPS testing as well

I made some progress on my danus knockoff thing tonight...my wife is working late and my daughters allergies are keeping her from sleeping well...so I can't get out to my shop to actually cut anything until this weekend. But I can still play with cad:



I haven't removed any material to save weight yet...kind of want to cut it out and see how strong it feels before I do anything like that. I had originally modeled the plates as 6mm since I have 6mm MDF on hand...but I doubt MDF would hold up and that would have been over 250g just in the two plates. Birch ply would be a bit lighter...Lexan (polycarbonate) would be heavier. I keep forgetting that...I learned that lesson on me old UMBQ that the angle quad was based off of. It originally had plywood plates which I later replaced with lexan for looks...and it gained quite a bit of weight when I switched to the lexan. It does look neat though.

Dropping it down to 3.2mm plates (~1/8") the weight drops considerably. Birch ply estimated at 117g, MDF (wouldn't even consider 1/8" MDF though) 118g, and lexan 198g.

That's just the plates...not counting all those standoffs, motors, esc's, FC, RX and FPV gear This thing is going to be a porker for sure but I was never really aiming for light weight, just something fun to bash around and get these parts in the air again.

That mockup motor is also an old sunnysky 2204 just because I found it already modeled in Onshape...I've actually got RS2205 red bottoms (with 30A littlebee blheli_s ESC's) that will be going on here. But there's only 1mm difference in height from the model to the motors I'm using even though the shape is a bit different so it's good enough for mockup.



The standoffs are really quick and dirty models as well, I made them 30mm tall...which "sounded right" but results in the prop not being well centered. I don't really want to make it much taller though so I guess I'll have to suppress my OCD and try to let that slide. I don't have that many standoffs so I'll probably end up 3d printing them anyway. And that would mean instead of the style I modeled with a threaded post on one end I'd make them with inner threads on both ends and use screws from the outside on top and bottom for assembly...which would probably be a bit cleaner anyway.

I also still have to figure out how I'm going to mount FPV gear...haven't started to model that up but I have an idea in my head (hence the flat area that sticks out on the bottom front.)

I'm also still undecided on whether to do the upside down motors and FC mounted to the top plate...or go with what I know and flip it all around. I'll probably stick with the dangling motors just because I've never done anything that way before so it's something different. Though even then part of me wants to mount the FC to the bottom plate to try and help isolate it from any motor vibration. But I'm not about to go buy enough o-rings to isolate all of those freaking standoffs

This should be a little bit more compact than the danus since I eliminated that center section and went more symmetrical. Should still be plenty of room for FPV gear I figure. I should add some slots in the top plate for a battery strap though....

 

[jhitesma]

30mm standoffs is a good start but may be short. Think the danaus came with 35mm standoffs. I'll check to see what is on my first build. Need to look at that before starting on the second build anyway so I can stock up on parts. It fits perfectly inside a typical large pizza box.... LOL!!! The owl can be done with 25mm but you need a pico camera or Runcam micro if you plan on mounting it between the plates. I've found these type frames do better in pusher orientation. The turbulence created by the props blowing on the motor arms seems to be a real hindrance. Maybe it would not be so bad in 5" form though... I would NOT isolate the plates from each other. Firmly tying them together greatly reduces frame flex and adds strength. The Danaus is a perfect example of this. The plates are pretty flimsy by themselves, but once they are tied together with the standoffs, it is actually quite a firm frame. Isolate the FC stack instead if needed.

Yeah, I figure 38mm would put the props in the center...I can see 35...but I think I'll be ok with 30. I'll probably just mock it up with 4 standoffs and 1 motor first get a feel for how my actual parts fit.

As for the cam - I'm thinking mostly between the plates - but I left that indent in the top so the cam can stick out if needed. So height between plates for camera shouldn't be an issue.

This should be somewhat smaller than the Danaus, I'm just under 12" from side to side. I'm wondering if I'm overbuilding it...but I can always remove more material after a first try. I was pricing delrin/hdpe/G10 sheets last night...CF isn't in my budget but I'd like to do something better than wood if I like the way it flies. HDPE is the cheapest - but I'm not sure if thin HDPE would be stiff enough. Delrin prices are all over the place...but with any of these the big problem is shipping. 24"x48" sheets tend to be the cheapest size per sqin but shipping on something that size is crazy. Wish I had a local place that carried plastic sheet goods. I should be able to just barely fit a plate into a 12"x12" sheet...but I'd have to be VERY careful on my setup to make sure it fits.

FWIW I wasn't really considering isolating the plates - just a bit of late night brainstorming about possible issues and how to address them. Wood is so good at damping vibrations I doubt I'll have any issues with the initial frame.

Wife finally doesn't have a meeting tonight - so I can get out to the shop and cut some parts Might start to mock this up tonight finally!

 

[jhitesma]

Icee..... Is that John I.?

No, mlyle. I always forget he uses a different name on IRC than the forums/github.

(Kinda feel like I should start a thread for this "build" but at the same time...like it's not really worthy of it's own thread)

I had good luck with the CNC tonight...not great luck...but I'll take it:



First problem was what I thought was 1/8" or 3/16" ply was actually 5.2mm so closer to 1/4"...thicker than I had hoped for. Second problem was it has a bit of a warp to it. I've had really good luck lately holding down my work using masking tape and CA glue. Basically I put tape on the workpiece and tape on my wasteboard - then put glue on one and spray the other with kicker and press it into place. Holds the work great including little cutouts - and it's still easy to remove after cutting.

But...this piece was just too warped for that...it was pulling the tape loose. And being 13"x13" stock it was hard to spread the glue evenly without it setting up first.

I've used carpet tape as well in the past - but it's more expensive, harder to remove, leaves more residue and if I cut into it really gums up my bit. But with this material I may have to go back to it. Then again I'm still considering cutting this out of lexan just for the cool look. If I stick with the ply I'm torn between doing a "natural" stain/sealer finish or my traditional hot pink....

Also, it took quite a bit of work to clean it up after the cut. Partly because the warped piece caused a few spots to not cut through all the way, and a few other spots to cut too deep and chatter. But also because I haven't really dialed in feeds/speeds for this ply so the cut was a little ragged when cutting in one direction. It took 18 minutes to cut and another 15 to sand smooth.

It came in at 74g for the sheet. More than I had hoped but less than I expected for the thickness of material. Debating if I want to cut the other side and assemble it first (I'll have to print a bunch of spacers) or look for some different material first. I already see a few small things I may want to change about the design so I think I'll finish mocking up with what I have just to see what else jumps out at me.

I'm really curious to see how it feels when fully assembled. It's not very stiff at all even with this fairly thick ply. I'm sure adding the other plate will stiffen it up quite a bit...but I'm also worried about how well this ply will hold up. The prop circles are a lot flimsier than I expected them to be.

Honestly though...it could ALMOST fly right now:



I need to cleanup the wiring a bit...once I decide where/how I'm going to mount the ESC's. But otherwise it's got everything it needs to fly. I may need to lengthen the battery leads...assembling it further will help decide that. Also my first time putting it together I found out I had it upside down so the motors didn't line up with the wires going the way I wanted. Had to remount the FC on the other side and it's all good now.

So...one way or another should be in the air this weekend....unless...this could be a problem:



Don't know if you can tell from this photo...but full size it looks like a fairly cold solder joint that failed. Not entirely sure waht that component is...it looks like it's right on the input of the ESC but it's not a ceramic cap. It may be a different kind of cap...but I can't quite make out the markings on it in the photo and am too tired to break out the magnifier to look tonight. Guess I have a little bit more soldering to do tomorrow when I clean up the wiring.


And...thought I posted this last night...but apparently never hit post. After I typed that up I went ahead and put some props on it to see how it's looking:



This is 210mm motor to motor, looks like I could shrink it down a little bit more...but don't think I will.

Also interesting...when this was built as the angle quad with the same parts it weighed in as 463g ready to fly....just popped this on the scale and it's about 270g. Bottom should be a little lighter since it doesn't have the motor mounts, so estimate about 70g for that...and my battery is about 70g. So that puts it at 410g...if the spacers and screws weigh less than 53g it will be lighter than it was before. And I'm still thinking the plates would be better out of thinner material so this may not be quite the hog I thought it was going to be. Still chunky...but not as chunky as I expected.

 

[LitterBug]

Looks really nice! Would look really slick stained and varnished. Don't see to many woodies out these days. I checked Danaus#1, and it does have 35mm standoffs. Props are pretty much centered between the plates, but that can vary with motor height and prop thickness. Think I may go with 30mm on Danaus#2. Will mock it up first before buying more standoffs.

EDIT: Oh nice, I just notced that is one of the beta DTFc FCs with a baro. Wish you could still get them with the baro. Was kinda ticked when I bought my first one and it didn't come with one. All the pictures and some of the documentation said it had one. I got over it. Have 6 DTFcs now LOL!

 

[jhitesma]

Looks really nice! Would look really slick stained and varnished. Don't see to many woodies out these days. I checked Danaus#1, and it does have 35mm standoffs. Props are pretty much centered between the plates, but that can vary with motor height and prop thickness. Think I may go with 30mm on Danaus#2. Will mock it up first before buying more standoffs.

I took my calipers to it and took some measurements...which resulted in me deciding to go 38mm with the standoffs.

Buy standoffs? You've got a printer - just make some, that's what I did



Gave them a nice big brim to make sure they stayed stuck...came out nice. Though I'll probably redo them in PETG or ABS or Nylon as the PLA has me worried about it's strength. Even if the translucent red looks really nice.



38mm puts the props just about centered. Hard to say for sure since I haven't tightened the prop nuts yet...but it's only about an hour to print a set of standoffs (and then another half hour to remove and reinstall all of them!) so I can adjust if necessary.

I'm going to have to recut both plates anyway. That warped wood is just driving me crazy. The tape and super glue method failed again last night so I went for carpet tape...which seemed to do well...until I started cutting and it started letting loose resulting in the frame plate moving and getting cut where it shouldn't have been:



So gotta hit the store for fresh raw materials before I redo this again. I'll be making a few other changes too. I think I'm going to add 4 more standoffs, most of the frame got very stiff once assembled but there are 4 spots with long unsupported spans that still feel weak. I didn't want to overdo it but now that it's assembled I'd feel better with a bit more support - especially if I find thinner wood.

Though...I'm not in a rush to make it thin just for the sake of being thin. Even with the stiffness I'm worried about the strength of the wood with the prop rings this narrow, and fully assembled it's coming in about 15-20g lighter than the angle quad was - even with a battery. So while it looks a lot bigger it's actually lighter than it was before. I put my old nighthawk 250 on top of it for comparison:



Now admittedly the NH250 is actually more like 280-290 motor to motor and sized for 6" props while I'm building this guy for 5". But still, that NH seemed small when I built it a few years ago so it's kind of funny that this smaller quad now feels big


In addition to the holes for four more standoffs I also want to add a hole for the battery cable to pass through. And, I had left off a standoff near the camera mounting area on purpose since I thought it would get in the way of mounting a camera. But now that I have it assembled I see I have tons of room:



Or maybe I'll go lazy:



That's tempting...should be fully protected in there but since it's wood wouldn't have the signal issues it would burying it inside carbon....hmmm..

Either way I'll do some kind of 3D printed camera mount that attaches to the frame so shouldn't need to modify the frame for that.

Overall looking good, one quick revision and recut on the plates and I should be in action:

EDIT: Oh nice, I just notced that is one of the beta DTFc FCs with a baro. Wish you could still get them with the baro. Was kinda ticked when I bought my first one and it didn't come with one. All the pictures and some of the documentation said it had one. I got over it. Have 6 DTFcs now LOL!

Yeah, I'm kind of thinking it may be fun to put a GPS on this guy and test some autonomous stuff with it...but I'd probably swap it to a seppuku if I did that. This DTFc may have the baro but I'm not sure if it's supported in code since most of them don't. I'm guessing he ditched them since most people don't use it and it adds considerable expense to the board since the baro is a pricey component and requires special processes during board assembly due to the hole in it. It is nice how clean the wiring is with the DTFc though. Or at least how clean it will be once I shorten some wires up

 

[cranialrectosis]

Very cool.

I concur with LB that you need some stain on that.

 

[jhitesma]

So...picked up a new sheet of ply and it's not as warped but still not very flat But I also picked up a can of 3M #90 hi-strength "Industrial" spray adhesive. So used that instead of super glue...stuck that thing down great and flat!

Generated new gcode from my modified files...and was looking great. I used a higher spindle RPM and that seems to have cleaned up the cuts quite a bit (Even though some other stuff I found indicated a lower RPM should have been better.) I'm running this very conservatively and taking 4 passes to cut 5.5mm deep. 3/4 of the way through the 3rd pass of the last cutting operation something shifted



It wasn't the work this time...the work stayed firmly attached for once. Something on the machine missed a step and caused to to get off. I was watching but must have been watching the wrong place as I didn't see it miss any steps or get caught on anything. But it seems to be in the same place that things got off last night so I wonder if this was what happened then as well and it wasn't actually the work coming loose like I thought (though the work WAS coming loose last night and that definitely didn't help.)

On the upside...I now know that at this feedrate and spindle speed I can take MUCH deeper cuts. In fact I would probably be ok doing a single pass...but will still stick with 2 to keep things gentler. That will speed things up quite a bit. But it's no fun cutting something this big and having it fail

Gotta do some house chores before I can play more. But have 2 more sheets of ply cut and ready to go for tonight so I can try a few more times. Just frustrating that every time I think I've got this thing dialed in and working reliably suddenly something unexpected happens again. Oh well, at least I can still cut foam with the needle without running into drama

 

[jhitesma]

Well, Cutting went from bad to worse

Next attempt failed on the very first cut with things going super wonky right off the bad. Restarted and ran it again (knowing it wouldn't matter since the work was already ruined) and it did well up until that last pass of the outside perimeter again. Grrr.

Ok, time to change tactics. Did a "dry cut" running the machine with no work and the spindle raised up a few mm extra but not running. And...Turns out the left Y roller on my machine makes some odd noises right at the point where the cuts were going bad. Hmm...probably not a coincidence that. That roller is slightly different than the other 3 (Printed out of a different brand of PETG) and has worried me before. My Y also tens to be about 3mm off from square until I square the machine and power up the steppers...so there may be some extra stress on that axis.

Well, I've been running my steppers very gently....the current on their drivers is turned way down. I actually run them with less current than the smaller steppers on my 3D printer. Mostly because, I can. The machine moves so easily that I didn't need more power so why turn it up higher, keep it gentle and let the motors take it easy. But...that was with the machine skewed and not squared up. With it squared it up takes a bit more to move.

So....let's turn up the current. Bumped the X and Y steppers up a bit, they're still running less current than my 3dprinter steppers (and the motors are still ice cold even after 40 minutes of movement) so still well within the safe zone.

And that solved it. I was too excited to stop for photos....gave it a quick sanding, and a coat of varnish then got it installed:




But...I wasn't done. I still had to recut the top plate since it needed extra holes for the new standoffs and the power cord. That went easy though - except I made one little mistake in the gcode:



Do you see it? My daughter even spotted it. Here's a closeup:



Yeah...I forgot to pick the motor holes on one arm

Grrr. Oh well. I took the original top plate and bolted it to the new one (the holes all lined up perfect - though it did expose a few issues with the perimeter cuts on the original plate) then used it as a guide to drill the missing holes. No big deal.

Re-assembled and:




I still haven't really cleaned up the wiring...I just taped it down and out of the way for now. If it flies well and can take a decent crash I'll come back and do that later. For now it's ready for initial setup/tune/test flight!

Loaded up the latest release of dRonin, let it do an auto-update since the FW on this board hasn't been updated in some time (I last flashed it when testing the blheli passthrough code.) Did a setup and promptly got myself confused over the "upside down" motors/ FC.

Eventually got my props mounted correctly, and found I only had to swap two motors in the setup. Did the dRonin level detection and all looked ok...so tried to do an autotune....but....no. It instaflipped on me.

At this point it was 11PM on Sunday and I didn't really want to keep pushing. But a few minutes later it him me..."Wait a second...was that artificial horizon moving correctly or not?" Nope. It was backwards and I had missed it

Did an automatic yaw detection...and with my roll and yaw now both at -180 (due to the FC being upside down) it took off and hovered great. Ran an autotune and got some decent numbers out of it. Higher gains than I'd seen on these parts before and respectable tau of 28ms (I did get slightly lower tau on here before...but that was with fresh props and right now I'm using some REALLY beat up props since I didn't bother to dig out fresh ones yet.) The build did come in a little heavier than before at 508g with battery added. But...that's using steel fasteners, and with 40 of them on here I could shed a good bit of weight by swapping to aluminum fasteners - I just can't source any locally so that won't be happening too soon.

The tune felt well, but a test flight in my small backyard in the dark doesn't say much. And I still have to get some kind of FPV gear on here. Will try and give it a better test flight over lunch, and if it survives that (I haven't flown anything but my 3D printed Gremlin in close to 9 months) tonight I'll try and get a camera on it.

 

[LitterBug]

Looks really SWEET! Guess I should finish dRonin-ifying Danaus #2 and get some pictures up. Maybe later tonight after I get back from a little paddling at the lake. I need an amphibious quad. FPV from the middle of the lake! LOL.

Cheers!
LitterBug

 

[jhitesma]

Yeah I'm pretty happy with how it came out.

It's surprisingly stiff with the 4 extra standoffs. But...I'm still concerned about how well it will hold up in a crash. Especially with the PLA standoffs. Now that the plates are cut correctly they seem stronger and I'm less worried about them breaking. But I can easily see some standoffs breaking. I really need to print them in PETG or Nylon if I want them to hold up.

 

[jhitesma]

So...test flight over lunch impressed me. Even flew it into a tree on purpose several times and it just bounced off and recovered great.

Then flew a pack this evening and started feeling frisky. Bounced it off the ground a few times but it just kept flying. Then did a bit more than bounce it:



Apparently the PLA spacers are NOT the weak point

Hmm...wonder how well a HDPE cutting board would machine.....

 

[LitterBug]

A little CA and it will be better than new! ;-)

 

[LitterBug]

Workin' on my dRonin Danaus...


Plenty of 30mm standoffs on hand. Any shorter and the motors would stick out the other side...

LB

 

[jhitesma]

I'm debating whether to finally try making some composite denim to cut...or finding a HDPE cutting board close to the right thickness.

I'd love to cut it out of G10 or Delrin or CF...but being 12" across I need fairly large sheets and the shipping on them is as much or more than the sheets themselves...and the sheets aren't exactly cheap to begin with

 

[LitterBug]

the shipping on them is as much or more than the sheets themselves...and the sheets aren't exactly cheap to begin with

Whuh?? Where you pricing them? Either your carbon is really cheap or your shipping is absurdly high. I see $12 shipping on 2 12"x12" 2mm carbon sheets @ $38 each from dragon plate.... http://dragonplate.com/ecart/product.asp?pID=3984&cID=94

Which is not cheap.... Would hate to accidentally mess the cut up on one of those!

Lit

 

[jhitesma]

Whuh?? Where you pricing them? Either your carbon is really cheap or your shipping is absurdly high. I see $12 shipping on 2 12"x12" 2mm carbon sheets @ $38 each from dragon plate.... http://dragonplate.com/ecart/product.asp?pID=3984&cID=94

Which is not cheap.... Would hate to accidentally mess the cut up on one of those!

Lit

Well...it's a tiny bit wider than 12" so I can't cut it from a 12" sheet...and the next size up is usually 24" which jumps into large package teritority.

I was talking overall price - I can find cheap sheet goods...but the shipping is expensive. Or like DP I can find expensive sheets with cheap shipping. Either way the overall cost ends up being way more than I can justify.

I found one place with really cheap delrin sheets that had me all excited. But then the shipping was like $50

And...like you said...I haven't cut these materials yet so there will be mistakes and a learning curve so I need more than just enough for the two plates.

icee said his DIY owl is using ply for one plate but acrylic for the other. I've had really bad luck with acrylic in quad frames, way too brittle. But Lexan I've had better luck with - other than it being heavy. I can get lexan sheets cheap at the local home centers though so I'll probably give that a try for at least one plate next.

I do like the idea of a denim copter though:
http://www.cartercrafts.com/micarta.htm
https://link.springer.com/article/10.1007/s12221-010-0060-6