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Mustang7302's iQuad Build Log

#1
Forward:
This is my second build log, even though the first (Bat Bone) build log was never completed. The first build was weeks and weeks in the making and patience got the best of me; I stopped documenting the build when I ran into issues and I clobbered things together in an attempt to get in the air. Little did I know at the time that the motor, prop, and battery combination was simply too much weight and power for the FliteTest parts; especially my lack of skill and experience. The sickening end to the whole thing was finally getting it in the air, though a little unstable, and my lack of pilot experience took it over a fence into mild traffic and the whole thing was run over seconds before I was able to run out and recover it.

Since then I had picked up new motors (NTM 800KV), ESCs (Turnigy Plush), and frame (Turnigy H.A.L Quad) determined that I would make the 4000mAh 4S battery and 10" propeller setup work. The extra weight tamed it down and it flew quite well. But it was ~1,800 grams of all up weight and any unintended returns to the ground was very prone to breaking something every time. Getting it back in the air turned into order after order for little things here and there. The FliteTest guys then debuted their Knuckles H Quad design and it inspired me to go lighter, simpler, and less dependent on manufactured parts. I stepped down to a 1800mAh 3S battery with the same motor and prop setup, built a couple of new H style frames from 1/2" dowel, and got my weight down to right around 900 grams. I could still get 10 minutes of flight time, versus the 15 minutes from the bigger/heaver H.A.L., and found I enjoyed the additional maneuverability and it was much more resistant to breakage in crashes. Even to this point I was still using FliteTest parts I had laying around like landing struts and G10 motor mounts; but alas I am out of replacements to have enough parts for a flying quadcopter.

With each rebuild of the frame making it simpler and lighter, I simply ran into the limitation of the heavy and low-ish KV motors carrying an extra 100 grams I didn't have too and the 10" props limiting how small I can make the frame. By this time the crashes and rebuilds have taken their toll on the components and its time to get new parts.

The iQuad Build Parts:
The iQuad Build Design:
Keeping to the spirit of smaller, lighter, and simpler I took to SketchUp to visualize the layout and dimensions and settled on the rendering seen below. Frame assembly is simplified by using wood screws to join the motor booms to the support booms which reduces the need for at least 12 holes and M3x20 screws from similar designs; also less fidgeting to get everything lined up. Motors will bolt, using M3x20 bolts, directly to the boom with washers as spacers for clearance of the spindle which protrudes from the bottom of the motor slightly. The carbon sheet is broad enough with three screws on each side to stiffen the frame to torsional twisting. The use of the four in one ESC, Q Brain, will eliminate the need for a power harness and simplifies the amount of wiring clutting.



Forthcoming will be a file for the template used to cut and drill the carbon fiber sheet if anyone is interested.

I ordered the parts from HobbyKing International yesterday afternoon and was delighted to see notification that they're in the mail as of last night. Paid a little extra for the "EMS Express" shipping to the states, so we'll see if it beats the usual 2 1/2 week transit time. More updates to the thread as they're ready.
 
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cranialrectosis

Faster than a speeding faceplant!
Mentor
#2
That small, its gonna be quick :)

I have a Knuckle I quad with 8" support rails and 10" motor booms. That puts my rotors 1/3 and 2/4 1/2" apart and rotors 1/2 and 3/4 3" apart. Makes for a very quick copter.

I use yellow front rotors and black rear rotors. I find that with such a small copter, the rotors are hard to use for orientation. I painted the rear boom bright yellow with black stripes and that helps a ton.

Good luck. Can't wait to see it fly.
 
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Cyberdactyl

Misfit Multirotor Monkey
#3
Mustang, may I suggest a slight modification?

Your motor's booms now are 10" with 9" main spar booms. It appears you have the main spars set apart roughly one-third as wide as your main booms are long. With the motors mounted with the shaft axis around 3/4" in from the end, that leaves your 8" prop's thrust column overlapping your main boom and main spar connection points (plates) right at 1". If you then have a plate or components inside that rectangle, you have a lot of unnecessary loss of thrust pushing against the main body.

I would suggest making the main booms maybe 12", and possibly keeping the main spars 3" apart, outside to outside. That leaves only the main boom interfering with the thrust column.

As it is now...
 
#5
Cyber,

That was something I was considering and would be a point of trial and error. I don't plan on having any plate surfaces, knuckles or otherwise, at the intersections of the motor booms to the support booms. While a bit of overlap of the thrust column over the support booms is not ideal for efficiency, I hope (trial and error) that the light weight and extra efficiency from the carbon fiber props would offset each other. I do certainly agree though that the thrust column should not overlap the center plate at all.

The center plate is going to be 4" wide and 4.5" long to allow enough real estate for the KK2.1 and the Q Brain to sit on the top next to each other and help keep torsional rigidity. A closer look found that the 10" by 9" boom dimensions was going to overlap the center plate. I've extended the motors out by 3/4" on the X axis for a new total length of 11.5" for the motor booms.

New rendering of a top down view of the new motor boom lengths:


Two of the primary goals here is to keep it as small and light as possible; anything to keep repairs quick and easy as well as maintain 9 to 10 minutes of flight time are secondary goals.
 

Cyberdactyl

Misfit Multirotor Monkey
#6
And I got to thinking, you said you wanted to eliminate a harness using the Q-Brain. So that may limit your quad's dimensions. It got me curious. . .how long are the wires on the Q-Brain for the motors?
 
#7
The Q Brain has about 10" of motor lead length for each channel, which is plenty long. It eliminates a power harness to power each ESC and it eliminates the 8 to 10" of servo leads from each ESC.
 
#8
So my HobbyKing order made its way into the states on Monday, landing in New York. From there though, progress and tracking has been sparse. The packages was handed over to USPS and on Tuesday it was in New Jersey, Wednesday it was in Indiana, and no idea where it is as of this morning. I was hopeful to see my parts this week since they made it into the states on Monday, but apparently USPS missed the whole "Express" shipping thing. Perhaps by Monday or Tuesday I will see my parts.

I decided I would start building the frame last night by cutting the booms to length and getting them painted. Motor booms were cut to 11" long and support booms were cut to 8.5" long. These are different measurements than previously discussed because I have re-done how I will do the carbon fiber plates to mount the electronics versus what was originally pictured; more on this later. With the booms cut and four #6 1.25" wood screws on the wife's kitchen scale, the weight come in at 90 grams. I expect the complete frame with CF plates, zip tie landing gear loops, and six M3x20 screws to come in under 120 grams before electronics are added.

By request from the wife, this build would have a blue and white color scheme. So I started getting the white paint done last night and still need to do the blue coats tonight. I plan on making the front half of the frame white and the back half blue; this paired with CF pattern grey/black in the center hub and on the props should make for a pretty cool looking quad.

Because pictures always make things better, here is the progress of painting the booms so far:

 
#9
Just curious, have any of you used the QBrain before, or can you post your experience once the build is done? I've never used a 4-in-1 ESC before and am wondering how well it performs. Seems like a pretty good value for $30 if it works well.
 

Craftydan

Hostage Taker of Quads
Moderator
Mentor
#10
It's an excelent ESC -- I've used it on 2 quads now. The motor leads are long and are pre-soldered with 3.5mm bullet connectors (female), It doesn't require a power distribution board, and the settigns are pre-programmed for multirotors. All told, all I've had to do to these is solder on the battery connector and swap the pins around to get the motor order the way I like it -- VERY easy setup!

And yes, the cost is excelent, even if you figure in replacements -- at the time I speced it, 1 QBrain + a spare Qbrain cost *less* than four comparable ESCs + spare ESC, and if you burn out more than 2 ESCs, you're doing something wrong, and need better ESCs!

Only downside is it can't take a SimonK flash -- wrong chipset -- but it should take a BLHeli flash, if it comes to that.
 
#12
Firmware like SimonK and BLHeli are more responsive to input from the flight controller so that the multirotor will fly smoother. Reality is that these firmware options are not needed for a smooth flying quad; but as you get more experienced and try to get everything out of it that you can, this is one of the steps you can take to get there.
 

Craftydan

Hostage Taker of Quads
Moderator
Mentor
#13
I'm unfamiliar with the difference. What is the downside of not using SimonK firmware on an ESC, particularly an ESC made for quads?
If you're unfamilair with the difference you won't notice it missing ;)

The improved ESC firmwares (like SimonK) have marginally faster response times (how fast it transitions from one RPM to the next). These firmwares will make a well tuned copter feel slightly more connected to your stick, however you won't notice it while you're still learning, and the first big improvment in "connectiveness" needs to come from properly tuning your control board -- a sluggish board will always be sluggish, no mater how good the ESCs are.

Think of board tuning as rough sharpening of a knife and the ESC reflash as honing the blade to razor sharp, but for learning, best to start with the plastic butterknife and work up from there ;)
 

Cyberdactyl

Misfit Multirotor Monkey
#15
One thing I love about flashing simonK ESCs is the satisfaction I feel pressing the pin header down on the ESCs metal contacts and seeing on my laptop;

################################: write completed successfully :cool:
 

Craftydan

Hostage Taker of Quads
Moderator
Mentor
#17
Pretty much -- it's just 4 ESCs tied together in a package convient to quads (assuming you don't need to draw more current than it can throttle). The control board is doing all the hard work, figureing out what the ESCs should be doing. Could even run a Tri on it, assuming you've got room in the cost and weight budgets for the unused ESC port.
 

Craftydan

Hostage Taker of Quads
Moderator
Mentor
#20
One thing I love about flashing simonK ESCs is the satisfaction I feel pressing the pin header down on the ESCs metal contacts and seeing on my laptop;

################################: write completed successfully :cool:
Compleatly agree!

Just something about a hacked peice of hardware -- makes me feel like I've liberated it from the clutches of "the man"!

Like saying to it "you were built for menial tasks but now you are free to do so much more . . . now get to work you machine slave!!!"

They are my minions, and alas, I am a hard task master ;)