Given the popularity of the 230/250 quads at the moment (blackout etc), I thought - wouldn't it be cool to have a rig that can do the ground skimming proximity stuff, but also with the normal "mod cons" of the APM?
Traditionally though, an APM would never fit. Until HK released the mini...so I built one.
I started with the Haldey-Bocks 230 frame, in Carbon Fibre. This was a mistake. I should have gone for the 250, because the fitting of the ESC's was a bitch of a job, especially with the thick 3DR power module hanging off it. And naturally, I forgot to solder in the XT for the video feed, so had to start again...
Anyway, this is the bare airframe:
So onto the fun part...
First, I fitted the camera, so I could make sure the clearances were good. I mounted it directly to the front CF plate to make sure I had as much room as possible behind it.
Second, I mounted the GPS antenna pole. This required a lot of trial and error, but eventually I found a position which worked.
Third, I fitted the APM mini in front of the post, and behind the camera. There is *just* enough room to do this. It is currently mounted with double 3M pads - I will review vibe damping after the first flight. Supposedly the blue balls do the "clean/dirty" thing, but is it enough to keep the APM within Z axis tolerances? Time will tell. These rcx are not the smoothest I have to say, and a propless spin up was really vibey.
I wired in the GPS, and the radio.
Then I mounted the 3DR telemetry radio to the roof. It is likely I will replace this with a minimOSD, and run a really simple OSD - volts, ground speed and home distance.
I then cable-tied the xt60 back on on itself on the PM - it was interfering with the props.
CoG is spot on, even though I thought it would be rearward.
Weight with tx will be 505 grams as you see it here. I have a wiring exercise to do (shorten and tidy), and to enclose the APM with some foam (for the Baro), and I hope that brings it down below the target 500 grams.
And that's it! It all fits together nicely. All the normal calibrations done - just compassmot to do (want to wait until I've got the camera and tx wired in first). Going for a really small 200mW 32ch 5.8. Will fit perfectly.
I didn't have time to get the thing in the air, but should able to get it in the air at the weekend. Can't wait to use DRIFT on this...:-)
Comments
@euan ramsay where can i buy Haldey-Bocks 250 frame?
In short, my flights have been very close to "home", so no real signal issues thus far.
Apart from the 3DR telemetry...I get around 10m range, maximum, even with 1/4 length 433mhz antenna on airframe(s) and 1/2 length on the ground station. I think my ground station radio is gone, because I have the same problem on all my aircraft and it doesn't really matter what antennas I use on either end.
The flights are going ok, but I still have a "bounce" when I "snap" roll or gun the throttle. And it's *very* sensitive to P and D on roll. The difference between "not enough correction" to "spinning out of control to the ground" is 0.002 in range. Pitch is totally nailed and rock solid.
Loiter is still horrific, but want to get stabilise etc sorted first.
It's been poor weather here in Switzerland (very windy and rainy), so not really had a good chance to get a load of tests done.
regarding tightening up your loiter, what HDOP are you getting when loiter is all over the place?
Euan - Keen to know how your flights are going. Also, how is reception of the telemetry radio, spectrum RX, and FPV with all those elements so close together? Keen to know a little about your telemetry antenna also. Haven't seen one like that before - did you build it yourself?
Do you have a video ? And log ? So i can check ... How % of gas do you have in loiter ?
I see that you put the battery very near the magnetometer it could be a problem is better if you raise the mag . Check allso vibration.
best
Roberto
I'm using CF 5030's, so PID's will definitely differ to yours.
Any ideas on how to tighten up my loiter? It's wobbling all over the place. Ramp up Loiter P?
Hi Euan,
my pid is bit different what's your propeller ? 5 or 6 ? I'm using 6 .
I'm testing auto take off , follow me return to landing point ... I'm using VR Brain with APM Copter 3.1.5 and VR Pad Station 2.0 on PAD
best
Roberto
Ok, a small update...took it out in 15mph winds tonight for it's maiden...and it flew! lol.
A couple of packs tuning it old skool (no autotune!), and I'm about 70% there. Pitch is perfect, roll is about 90%, yaw is perfect. I'm running conservative settings - I'm pretty sure there's a rocket ship under the hood - I can feel it. :)
However there were two problems.
1. Loiter is all over the frikkin' place. Up and down altitude (that's due to the uncovered baro, which I'm fixing as we speak), and really "unlocked" pitch and roll. Admittedly it's windy, but in stabilise, it held it's position better. Any suggestions? Screenshot of settings attached.
Could it be the compass interference? I ran compassmot 5 times, and got values of 31-40%. Loiter is not toilet-bowling - it's holding it's heading extremely well. It's just very, very wobbly.
2. For some strange reason the ESC's like to stall after arming for some reason. Arm...run them up...and one will stop after a few seconds and just twitch. Disarm, re-arm immediately...and it'll be fine! And it's never the same ESC either - the two rear are the most likely to do it, but the front's do it too. If you arm, spool up slowly but immediately, you can fly an entire pack without problem. Ideas?
As promised, here is Hadley: https://www.facebook.com/cardboardboks
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