I'm glad to say I'm helping myself to a beer tonight....my first ever design flew tonight!
It was a dark, windy night, and I had to light "home" with my car headlights...but it was enough to get it in the air, hovering and even moving about.
And what can I tell from this short, windy flight?
- Well, it's massively overpowered without the gimbal and nex5 aboard. Tomorrows daylight flight will include this weight to even it out.
- It's stable in the wind. Wow. And some. I'm getting pelted with leaves in the bluster, but it's just slowly moving about, even on stabilise. No histrionics - no mad plummets or bounces. But with 83cm between the front arms, there's a lot of weight and leverage to keep it that way. It's so good I'm calling it "Terrance". Fans of the Angry Bird cartoons will know why.
But the true tests are to come. Will the "very forward of CoT" CoG caused by the gimbal destroy the handling? Will the APM react ok being off centre? How will it handle getting thrown about properly? Should I dump zeal, and go back to moongel (see chart below), based on the worse-than-wanted vibes chart? Can I improve on the 15% Compassmot (yes, I can)?
But most important of all - and the reason it was designed - does it make a good video platform? Time will tell.
Comments
How much flight time are you getting/or planning to get?
Nah - didn't get out today, with the rain again :-( Not to worry - will post the data the moment I have it!
GG Euan! Nice step forward with your project.
By the way, did you measure during your first flight how much amps you draw with these four motors and 1555 props ? Which 6S batteries did you use ? what brand (turnigy, zippy, maxamp,else...)?
Does your measurements match and confirm Forrest's measurements on his testbench ?
What flight duration do you get ?
Sorry, lots of questions but impatient to learn more....
Interesting. Those are the props I tried on my long endurance hexa with rctimer 5014 motors and they caused the hexa to consistently tip over. I'm now using the slimmer 1555's they sell. This was flown next to a high-rise building, so you get some strange wind flows there, but it wasn't extreme. rather than ask about every little detail here, do you have a link to the build specs?
These are rctimers CF 1555's, mainly because these are the ones Hughes is testing over on his tmotor 6S thread :-) I have the lower pitch Tmotor versions (noticably better quality btw) for later when im hopefully out of the "test crash" phase.
And the prop brand? There's a couple in the market and one brand/model I used from rctimer had severe issues keeping the rotation going.
Sunnysky 4112's turning 1555's with 6S. See also tmotor 3515's, but they're noticably heavier.
What is the prop/motor combination on this?
Hi Euan,
That is a really nice Quadcopter.
The MoonGel won't improve it over Zeal and it has a couple negative characteristics (melting).
However, basically your Z vibration is just slightly over + and - 1/10 G so it is really good anyway.
The reason it is not as good as your smaller copter is probably connected to those really big slow props on pancake motors, both prop vibration and flap and inertial response slowness (motors speeding up and down to compensate for stabilization) can increase vibration.
But yours still looks really good.
As far as the APM being off center from the turning center of the copter, yes it will have an effect.
If it is turning around the center of the APM the Accels are displaced quite differently than when it is moved away from the center.
However, most of our copters generally have the APM placed well above its turning center (prop thrust centers + G/G) and don't seem to suffer noticeable degradation.
So clearly some offset from center can be tolerated before the effect becomes noticeable.
Relative to the horizontal prop centers on your big quad the offset seem fairly small so likely the effect is not very important.
You might want to consider adding a secondary vibration platform if you want to cut vibrations further using O-rings or grommets.
Of course if you wanted to get really serious you could add a secondary isolated high mass platform that held both the batteries and the flight controller.
Others have gotten down into the 1/100 G range doing this.
SteadiDrone uses Vibration Isolated motor mounts to achieve surprisingly good results.
Morli, I'm not actually sure at this point <blush>. I'll know after the next prototype (since it'll be the last one). I'll be sending out a few frames to guys here for independent testing in a couple of months..
I'm trying to get the full frame kit on the market for around $350, but there are number of factors I need to consider first - the main one being whether I source the CF cutting here Switzerland or China (long story).
Another thing is some of the component quality - good example is the M2.5 bolts. What a nightmare trying to find good ones that you'd actually be happy giving to others! Then there's the colours of the metal components...they should all be Cyan blue, but of course, they're not...
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