Heavy Duty

By Nikotttin on Apr 05, 2020

17  1,285  8

I had this 20x20 4 in 1 15A ESC an a FC lying around. I also had a Foxeer Predator micro cam... All that is pretty heavy. I used it on a pseudo-toothpick and that flew nicely... BUT... I broke the frame against a wall...

And here starts the nightmare.
While changing the frame, I've removed one of the xm+ antenna. Trying to put it back together, I removed the other one, and ripped one little u.fl connector. Ok Ok... just put a new antenna, right? I couldn't get that new antenna to connect! the connector on the XM board was skewed... Eventually I managed to put it all back together... glued antennas to ensure these hold...
Quick tip: Put some heat shrink tube on the antenna near the U.fl connector... It significantly helps

I had a nice GEPTR 12A AIO... I soldered an XT30, nothing else, plugged a 2S battery... and sparks everywhere and magic smoke! GEPRC said it was just some "dirty" pads and I should go ahead with my build. I did so and somehow managed to short all 4 1105 motors! AAAAGGGHHHHH!!!! Rest assured that I had checked for continuity and my soldering was as it should. Maybe were the motor screws too long? Maaaaybeee? Seems odd though. Thankfully GEPRC offered a new FC and some 1204 motors at a discount. That's for a future build.

Time to spend some money:
I wanted a small build that was resistant. I was really annoyed at breaking everything that landed in my hands. Who says "resistant" also says "Uh, that's a heavy one!"... I thus needed motors with sufficient power to liftoff. Something larger then my 1105. I also wanted at least 5 min of flight. Not full time aggressive flippy-floppy... but some decent flying.

I thus made my choice:

  • new EMAX 1404 motors
  • a cheap SIRIAN frame that can take some 20x20...
  • My 20x20 15A ESC
  • A AKK race VTX
  • The Foxeer Predator

About the motors
I selected the 3800kv motors to have a max of efficiency and experience that throttle resolution everyone talks about. I also wanted a 3S power system... The motors are nice. They're notchy, but not uber so. They're nicely made and seem very resistant. The bottom as a clip as expected and a 9mm diameter mounting pattern. Consumption-wise, I have a 15A HAKRC 4:1 and have had absolutely no issue. Full throttle on bi- and tri-blades, no problem. Question of feeling, the quad hovers at about 25-30% throttle. Full throtte sends the quad in orbit... Motors are about 9.6 gr with the cables each. Cables are 10 cm long and made of nice quality 23-25AWG silicon wire. Heavy compared to my 1103 and 1102 :)))

About the frame
The frame is quite frankly amazing. I'm super happy. It's heavy at 33gr compared to a toothpick. The bottom is 3mm and there very little flex, although the cut is not made along the weave. It has a front mount for a micro cam, the space for the tower in the middle, 20x20 or 16x16, and an "X" shape in the back where to ziptie things. The 8 mounts are M2, 22mm in height and made of metal. That's too many mounts for a 3inch. I thus use only the front ones, the back ones, and the ones immediately after the tower. I also used my own mounts, because they're a bit lighter and shorter (20mm) giving a bit of a slant... The top part is 1.5mm thick and nicely cut, making space for the strap and giving plenty of place where to mount stuff. Screws are M2 5mm in length and metal... Heavy duty :)

About the build
I did not shorten the motor wires, as I will move all that to a 4 inch at some point. I used 4x 20mm long M2 screws to mount the tower. The 4:1 ESC is on a plastic thing to separate it from the carbon. I then added some rubber mounts from whoop boards, the FC, and a M2 nylon nut. Works very well.
The FC is a HAKRC F4 with lots of UARTs. I could add a GPS at some point :) I zipped tied the AKK race VTX in the back. Very nice transmission for the same weight as the whoop VTXs and with mounting holes (16x16). The VTX antenna is a UXII... brilliant range without breakups. I passed the ziptie straight on top of the U.fl... ensuring it stays there. Since I wanted an heavy duty efficient quad, I also added a bipper... Great for LOS flights, as it bips when the battery is low. Love that! That's ziptied on top of the VTX, over some cables, making the whole thing a bit cleaner. The whole quad is 98gr. And that's about that.

What about props
I use stock BF4.1 PIDs with a 1.2x PD gain. I flashed JESC 48Hz, as I'm usually in the mid-throttle range... and quickly full stick for some acrobatics.
For props I tried HQ 3x3, Genfam 3x2, and HQ 3x3x3. After about 20 packs, I am all for the 3x3x3... But I only flew in confined spaces where speed is not a must and where failed cornering means aiming at my neighbors roofs... or some trees..

Some notable crashes
I initially did only use floss to push the props. Bad idea... It does not hold in tight turns :) Props are now secured with proper screws. I clipped a concrete gate yesterday and I also hit a metal post dead-on... and hit a tree to crash-land onto a roof and spin down with some partial control onto the ground 8m below. That would have killed a toothpick. Here... Nothing! Absolutely nothing!

Heavy duty is its name and it deserves it :))))



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Shackmir   Apr 13, 2020  

What is the flight time?

Nikotttin   Apr 18, 2020 

It depends...
3S 450 mA: about 3 min pushing it
3S 520mA: about 5 min pushing it
I just ordered one 850 3S and a 4S to see. These motors suck Amps...

On every cool thing is the very... and I mean VERY... linear throttle management. You can "explore" and go about. Since there's no props in view, it could become a cool cinematic drone. Now from a freestyling perspective, these motors lack (on 2 and 3S at least) a bit of pop. It seems more suitable again for exploration.

Fun fact: I'm used to light weight micros and all my split, power loops, etc are off synch. Today I just broke a prop! Agh!

Nikotttin   May 10, 2020 

4S 700mA: 8 minutes racing and flippy flopping 14 min crusing
3S 850mA: I stopped at 8 minutes... I could have flow longer. A bit less pop, but still good
3S 520mA: 6:30min, mix between punch outs and racing
3S 450mA: max 5min pushing it...

Xacto   May 01, 2020  

Very nice! What is the motor mounting on that frame? Can't find that info anywhere... looks like you used 9mm but I've saw another build on here that used 12mm.

Xacto   May 01, 2020 

Can the frame take either 9mm or 12mm then?

Nikotttin   May 02, 2020 

either 9 or 12 it seems indeed
aorry needed to check before answering

DrMacca   Apr 06, 2020  

Looks good and great write-up!!! 👍

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