I built my first quad from scratch. It's based on the ArduCopter. I used aluminium towel rods for the arms and some sixteenth inch aluminium plate for the support and sixteenth by half inch strips for landing gear. The motors are A2217-9 950Kv, APC 10 x 4.7 props, Hobby Wing 18A ESCs, Hyperion 4000mAh 3s lipo, and an APM 2.0. The total weight is at 1449 grams.
Above is a picture of the quad before I hooked everything up. The ESCs are wire-tied to each arm and the battery is strapped to the bottom of the platform. I also have a plastic food storage tub that I strap over the APM for protection when I fly.
I've flown fixed wing and mini helicopters but I've never flown a quad before so I was a little nervous. My flying location is 7200 feet above sea level so I wasn't sure what to expect with respect to power and response but there were no problems at all. I followed the "first flights" documentation and flew many short, low altitude flights to get a feel for flying. I had to pitch backwards a little to hold in place so I need to do some tuning. The pitch wasn't so bad I wanted to stop flying to tune so I kept going. I hit the throttle a little to much and the quad zoomed skyward to 80 or 90 feet. It then drifted between the sun and my eyes. The next thing I did was panic and cut the throttle. That resulted in the quad dropping out of the sun and sky at an alarming rate. About 20 feet from the ground I added throttle. I was successful in slowing the decent to the point where I thought I could land successfully. I was still a little nervous from the prior happenings and when I landed, the quad was moving sideways faster than I thought and the left two landing gear touched the ground and the quad flipped over and one of the props busted. I didn't follow all of the advice in the documentation and did not purchase extra props so I'm grounded for a few days. Even with the bad landing and busted prop, it was a very good experience for my first flights. The APM 2.0 performed flawlessly. The hardware and software are amazing.
Comments
Sorry, just to make it clear, on that last point - holding the rig in the air and running the motors - you need to do this with the props ON (as opposed to the method without props that Tony said he had already tried).
Hi Kur and Tony. I am also pretty new at this and have been testing my first quad for the past few weeks - at irregular intervals while inevitably waiting for new parts!
One thing to watch out for when experiencing drift on takeoff is even weight distribution. Just make sure that one side isn't heavier than the others.
Another thing to check is that the APM has been leveled properly. Violent inflight movements can upset the settings and it can pay to re-level by performing the ESC disarm movement on your transmitter (hold throttle down and to the left for about 15 seconds) - making sure the rig is level at the time you do this. I am pretty sure this particular technique has helped me on at least one occasion.
One more thing, hold the rig in the air with your hand and start the motors slowly and see if the rig remains evenly balanced with some thrust applied. If not, and you find that one arm wants to swing up, then something is wrong. My best piece of advice in this instance is to pull out all the wiring and reconnect everything one step at a time while following the instructions. I thought I had everything setup correctly - but after triple checking, it worked out I had misunderstood an instruction and placed the wires in the wrong spot. This technique will save you a lot of propellers too!
Good luck.
First of all congrats on your maiden flight. I alss had my first maiden flight yesterday. Here is the video https://www.youtube.com/watch?v=CTkMQjI3_XM
I am also having the same issue as you are. As soon as I take off quad just goes in the forward direction. Even thought I am not giving any command to the quad except throttle. I am also not sure which PID should I change.
Hope, somebody helps us out.
Once again, congrats.
Cheers,
Kur
Congratulations !Tony Good Luck R.D.
R.D., I hope your tests and flights go well. I did lots of test holding the quad in my hand (without props) to make sure motors sounded like they were doing the right thing before I even attempted flight.
Question for all:
As I mentioned above, the quad would pitch forward when taking off and I had to pull back on the pitch to hold in place. I've read many tuning comments and the manual but I'm still not sure what PID to change if any. On the AC wiki there is a document called AC2_Tweaks. It talks about flying in auto-trim mode in windless conditions. This seems like it might be my answer. Can anyone confirm this or give me other ideas? I have leveled the quad on a level surface and checked with a bubble level.
Thanks in advance
Congratulations on your maiden flight!
I bought some extra props today but my local hobby shop didn't have the pushers needed. They ordered them and should arrive by Friday of this week. Just in time, I hope, for some weeked tests and perhaps a maiden flight.