The CyberQuad

[jhitesma]

I'm pretty sure the tips are resonating like a reed in a tuba.

As a relapsed brass player myself I have to take offense at this. Reeds are for woodwinds!

As for what causes desyncs...it's a mix of hardware and software. Some versions of SimonK an newer versions of blheli are better than others. But the better hardware on the KISS makes it easier for them to avoid desyncs. Bigger and pitchier props also makes it more likely to happen.

What it comes down to is that what ESC's are doing is pretty mind boggling when it comes right down to it. Well, actually it's simple - just just have to turn 3 switches on and off. That's it. The FET's are those switches. That's why you have three wires coming off your motors. A brushless DC outrunner works by turning windings on the stator on and off to attract/repel the magnets on the bell. The faster the motor goes the faster those have to be turned on and off. If the ESC looses track of which is supposed to be on and which off and does so at the wrong time you end up with a desync and instead of pushing the bell around the motor momentarially tries to turn it the opposite way.

This is why KISS ESC's are so much quieter and why people are seeing longer flights with them. Having faster FET's that are able to switch on and off faster along with better software that keeps them from loosing sync the motors run better because they're not fighting themselves when the timing gets off. How much does the timing have to be off? Well, let's see...2400kv motor at 12v would be almost 29k RPM or 480 revolutions per second. So every second that bell is going aruond 480 times. To get around once the coils have to be switched several times - it varies with the wind of the motor and polecount but we'll go with 6 for the sake of argument. So that's about 2,800 times a second things need to be switched. That's why I say it's pretty mind boggling despite being pretty simple (I admit though my math is probably pretty sloppy tonight I'm not doing well with numbers today and I'm blaming this head cold!)

Even if my math is off on the exact numbers the point is those FET's are switching on and off thousands of times a second with these high kv motors. They still switch pretty freaking fast even on lower Kv motors, but on high Kv motors things get mind numbing fast. That's why desync's weren't a common problem until the rise of the mini's.

 

[Cyberdactyl]

Opps sorry, I'm not a musician. I assumed all of "them" used a reed.

I've been over at the AfroESC series forum at Rcgroups and many agree I should update the firmware no matter how recently I bought them. I agree, in that the version may be as far back as late 2013. I have the flashing tool coming in a few days and will update to the latest.

It only desyncs with 4S, but I really want to try 4S. It's that urge to have want you can't when it's right at your fingertips.

 

[jhitesma]

Opps sorry, I'm not a musician. I assumed all of "them" used a reed.

I'll let it slide this time For the record yes something has to vibrate to make a musical note - in brass instruments like the Tuba it's the players lips, in a woodwind it's a reed in the mouthpiece. There are some crazy people who make cross-over instruments but they're just crazy In a string instrument it's the string of course either from being hit by something (like a piano or harpsichord) or from a bow rubbing across the strings or plucked/strummed like in a guitar. I still have my horn but the past 7-8 years I've been having fun building and playing cigar box guitars...though I have 3 builds on my workbench that haven't been touched in almost three years thanks to my RC addiction coming back to the surface



It's not quite as pretty anymore...that was right after I added the pickup about 3 years ago. Since then it's got a lot of use and with no pickguard it's starting to show. Not quite as bad as trigger (Ask a Willie Nelson fan ... or google) but I should probably put a pick guard on it if I expect to hand it down to my daughter when I'm too old to keep playing it

Yeah...I've got too many hobbies

I've been over at the AfroESC series forum at Rcgroups and many agree I should update the firmware no matter how recently I bought them. I agree, in that the version may be as far back as late 2013. I have the flashing tool coming in a few days and will update to the latest.

From what I remember the firmware on the Afro's was already out of date by the time they hit the market...and HK being HK I doubt they've been updating them If you have an arduino laying around you should be able to use that to reflash them through the servo wire. You could also try blheli on them, it has some additional options available and is reportedly better about avoiding desyncs.

It only desyncs with 4S, but I really want to try 4S. It's that urge to have want you can't when it's right at your fingertips.

Not surprising...the harder you push them the more the limits of the hardware start to show up

And I know that feeling...having this Twitchity quad here but not being able to fly it because of my bearings is killing me!

 

[Cyberdactyl]

I'll let it slide this time For the record yes something has to vibrate to make a musical note - in brass instruments like the Tuba it's the players lips, in a woodwind it's a reed in the mouthpiece.

In that case. . . my brother's quad sounds like lips and mine sounds like a reed.

At first I thought that was an actual cigarette. . .

Also, found an example of vertical booms being used. They appear to be airfoil in shape, but it's hard to tell. Even the screen guard is elongated in the vertical to reduce the underside turbulence.

This article along with the kickstarter page, provides pictures, plus the design problems he's run across over the last couple years. Since it never really leaves ground effect, it would be a bit misleading to say it actually "flies" anymore than a skirted hovercraft flies. Although he does suggest it will eventually fly out of ground effect.

 

[cranialrectosis]

Bet that bike doesnt sound like lips or a reed. Bet it sounds like thunder!!!

 

[Cyberdactyl]

WooHoo, I flashed my mini's Afroslims 20s late last night with simonK's latest 6-18-14 NFET and the 4S desync is gone. . . on the bench.

I'll push it hard over some tall weeds this weekend and find out for sure.

 

[cranialrectosis]

Video of it being pushed hard?

 

[Cyberdactyl]

I just wanna see the video with the chunky looking little meat grinders on.

How did that fly? You said there was vibe but with a tri-blade there is always vibe. Did you leave a vapor trail when you did a punch out or what??

Here ya go. I didn't get crazy with them on, they shutter the cage pretty bad when I push them. Now time for them to retire and put back on the HQ 0645s.

https://vimeo.com/105505473

Video of it being pushed hard?

As to pushing it hard, that will have to wait until I have more space. If I had FGAs skill I might go for it, but in my tree box, with my average skill, and it being a dot after a couple seconds, I'm reluctant.

 

[cranialrectosis]

With that red light on it, I was reminded of HAL.

That copter is crazy looking. I like how you solved the landing strut question that is typical for minis.

 

[Cyberdactyl]

Thanks. I have to be a bit delicate landing on hard surfaces because of the sharp point of CF and also the bullets are only about 3mm off the surface. I could easily chip away the sharp angle.

I may come up with some kind of rubber nib to put on the landing tips.

 

[cranialrectosis]

What does video from the copter look like?

You have some gnarly looking vibration mitigation. Did you fly with the GoPro on?

 

[Cyberdactyl]

I did. But I took it out directly from 73F into 95F with 70RH and it fogged up the lens. I forget and do that fairly often and screw up the video. When I FPV, it doesn't happen, because I instantly know since I can't fly. The camera just needs to acclimate for a few minutes, but I forget when I LOS fly.

Once I'm confident something won't happen I may try some FPV with it. One design 'issue' I have with mine is the card cam is locked up inside, so even if I use the GoPro, the card cam has to ride along too.

I'm SOO looking forward to fall. . . no more heat or humidity and the bugs, for the most part, disappear.

 

[Cyberdactyl]

Got some late Sunday afternoon video using MUCH nicer props.

As I said, 3S and not venturing much above 85% throttle is best for now in the yard.

 

[jhitesma]

I may come up with some kind of rubber nib to put on the landing tips.

Plasti-dip! May take a few layers but doesn't add much weight and gives a nice rubbery protective coating.

 

[Cyberdactyl]

Good idea! I have some black liquid electrical tape that would probably work.

 

[cranialrectosis]

It looks like a nice stable copter with HAL observing everything that happens below it.

 

[Cyberdactyl]

It looks like a nice stable copter with HAL observing everything that happens below it.

Yea, I originally designed the UBEC to go 'inside' between the boom clamping plates. I was a bit disappointed when I got from it from HK because it turned out to be about 5mm wider than I designed for ...and cut, (I modeled a simple rectangular box the same width as the Afroslims and forgot all about it). Turned out to be much too tight to put it in between the clamping plates with the power and control wires. I would have had to really pinch the wiring against the CF boom edges and screw threads So I threw on the back.

Well, when I was having the de-sync issues with 4S, I thought it might be the ESCs getting too hot from being covered. So I got serious about finding another place for the UBEC.

Then I saw it. Under the plate for the KK2 are the cage upright plates! They extend down 7/16" and are 7/8" apart, a perfect place of protection from everything save a sharp impact point. I even took the ferrite torus and slipped it on the ESC bottom guard in the back. Actually, I like the UBEC better there because it adds more mass to the floating cage as opposed to having it where I originally planned. I couldn't have designed a better location.

 

[Cyberdactyl]

Thanks for the idea jhitestma.

It seems to have worked pretty well. I'm using liquid electrical tape and it's resisting peeling . . .so far. The pic below is around 4 coats. Not sure how durable it would/will be on a lateral landing on a driveway or sidewalk, but all I wanted was a bit of protection. I can always re-coat!

One thing it does do very well is act as a non-skid, non-scratch edge on my kitchen bar and house flooring.

 

[jhitesma]

I was actually going to share that I had another idea - Sugru. So if the liquid electrical tape doesn't stay on you may want to look into that

But glad to hear the first idea is working!

 

[Cyberdactyl]

Ok, I tried my best to grab some quick video of my mini with a 1300mAh 4S 50c. I'm truly past my skill level with anything above 85-90% throttle. I'm hovering around 30%. I also have the KK2 stick scaling set at 90 on throttle as well, so I'm assuming I'm not going much above ~80%.