I emailed the guy that sells and installs a large number of MK boards in the US. I believe he's the number retailer in the US for Microcopter. He gives a lot of very good information that I felt I had to pass on to everyone in the forum. I figured that he probably knows as much as anyone and I consider this information more to be fact that speculation. The highlights of this email includes: 1. Only fly with with PH on dynamic and varo settings 2. Having a cell phone in your pocket or being near powerlines or your car while calibrating is far worse than being off true north 3. Heat shrink your lipo wires all the way to the battery and long lipo cables can cause compass issues 4. Make sure in MK tool under AH you are set for center stick 127 for vario not auto 5. GPS hold needs to be set to dynamic and the stick thresold is set to 8 Here's the email I only fly with PH on.. Dynamic and Varo. the horror stories are from people that don't know what is going on with their systems before they fly for the most part. Loading way points and not remembering then they hit CH and it goes to the Way point, ect... Pointing due north is not that important, its mainly you keep the same direction throughout the process. Yes you should point as close as you can but a few degrees is not going to make a difference. If it gets bad values it it will fail with errors. Somtimes using two people to spin the system helps make it smoother. Having a Cell phone in your pocket while you calibrate is far worse than being off true north. Being next to your car or powerlines is way bad.. You must be out in a clear area. at least 50 feet in all directions. When flying, large metal objects will mess with the system. Railroad tracks, powerlines, ect.. Flying off a metal ship deck can cause challenges. Sun spot actiivity will also cause strange things, But you must know how to turn off the Navi quickly if you see something strange. I have a sun activity meter on the forum too. If you do not Calibrate the compass, yes you will have problems. but as with anytime you see something happen that just seems strange like it goes in a direction you think it should not, turn off PH and fly.. the compass affects how smooth your system flies, it uses it to keep the MK straight. even when not on GPS hold. if there is a problem like getting compass errors it will fight to keep pointing in the direction you want and you essentially will be running on only half the motors. So if you get compass errors from not heat shrinking your Lipo wires all the way to the battery or not twising all the DC wires you will see the nose shake back and forth. If you notice every other motor is hot too is a sign of a compass problem. The biggest Cause for compass problems is from Long Lipo cables. You must keep the Red and Black together or you will cause a lot of EMF. I heat shrink them from the Power dist to the Deans, and on the lipo the entire length of the wires. so there is no place they can separate. One thing about the forums is there are a lot of people doing lots of strange mistakes and blame the system. if built as described and used as described they work awsome and for a long time. Understanding your system and knowing what switch does what and how to tell that it is setup correctly is much harder than flying. Also tons of miss information and lots of people making it harder than it is.. I try but I can't straighten out everyone. So here is how you should fly with PH on for the first time. after you know your calibration is good.. there is nothing to worry about as long as you get all the correct beeps and no strange beeping or errors on your radio. Once calibrated you can check the MKtool for errors too. I'll talk about using a Gruapner MX20 radio for this part, so if you are not your settings may vary. Make sure in ALT hold in the MKtool you are set for center stick 127 for vario, not auto. GPS hold is set to dynamic and your stick threashold is set to 8 or so. "look around you'll find them" Double check your POTI and channels are set to their correct switches you want for GPS Hold and ALt hold check them in the Channels section in the MKtool, make sure they are correct. So then here is how you fly this way. I turn on the Kopter then when the Beeps start because its mad about no radio I then turn on my radio. " I Know this is different from other RC equipment but this works, it lets me know the radio is connected and all is good. then wait for the GPS light or turn on and off. PH and make sure you get no beeps, if the GPS is not locked it will beep, beep, beep. once locked, Cal the gyros then turn on PH befored starting the motors. its ok before or after I like before. start motors and make sure you know where your Alt hold switch is. Holding down the Throttle, since its springed to center on the MX-20. then let the throttle come up to center and once about 10 feet off the deck hit the ALT hold switch.s it should just hover right there, on a calm day.. this is where you watch the MK and make sure all is good before you take off to 1000 feet or so. just watch it and is should sit there without too many jerks or strange things going on. then adding Gas past center it will go up below center it will go down. then pushing sticks around it will go and if you let go of sticks it will just stop where it is. the best thing about flying this way is if something goes wrong you just let go of all the sticks and it stops.. again this is only with a springed throttle. CH in my book isnt necessary since its so easy to fly it back using this method, Before you test CH make sure you understand the CH altitude, it will go to that alt. when it comes home so make sure that is clear of anything in its way. also remember if its lower than your CH alt it will go up .. Also work on understanding what happens in an emergancy , loss of signal or power.. make sure it set to use vario and about 80% is a good place to start. hope this helps Ziggy
Dave thx for the follow up to my post. My pilot/tech dude took it apart and made some of the adjustments your guy has suggest. We'll take it up on Friday and see if this addresses some PH issues we had. We'll also recalibrate the compass before we take it up and see if that makes a difference.
Alot of great tips I am not sure if I agree with him, that it is ok to turn on PH prior to takeoff. To me that seems to be a recipe for a potential disaster, coming from the military and commercial aviation world with redundunt systems I have had a few times I have had INU/GPS receiver suddenly get bad data and had the system reverted to the backup system. Since we do not have a backup system there is no way to mitigate it if the system is having a glitch. Takeoffs and Landings are the most critical phases of flight it seems like that this phase of flight is a bad time to figure out that you have a Nav system error. In my opinion the safe thing to do is get off the ground and stabilized before turning on the Autopilot.
I am sure it does work well most of the time. It is when things start to malfunction at the undesirable moment such as on takeoff or landing. To me its not worth the risk, Not sure what the benefit is for having it on during takeoff.
I understand your reasoning. After reading all these posts on the subject I feel all PH and AH issues are related to compass value errors. I think that as long as you calibrate the compass at each location, and you check the rotorcopter for any errors through Xbee you should be fine for the rest of the flights. It's probably also best to do a quick 10-15 second test flight that goes about 8 foot high and check the logs for any signs of problems. These are the practices I am going to incorporate when I fly. I am going to do everything for redundancy as well like flying with 2 batteries and not making any changes to flight software on location.
Generally you only need to do a compass calibration if you drive a considerable distance east of west. If we are only accurate to within a few degrees as we do the procedure driving 10 miles from your calibration point is going to have a negligible effect. One degree of longitude is about 68 miles give or take. So I've always thought that for anything less than that or even larger distance away the chances of messing up the process, not being pointed any better to mag north, probably will have little to no effect on the copter. In other words more chances to screw up a good setup.
I think our compass is off. The weathers been bad so we haven't had time to take it back up. I think we've sorted through all the other issues and I think this is the last one.
HI Gary I am no expert by any means and people on this board probably have forgotten more than I know but from all the research I have done on this subject it appears that many people believe local magnetic anomalies will cause problems form anything such as power lines, buried metal pipes, rail road tracks etc. So I am not confident that we can rely on web-sites to tell us specifically what's going on at a particular place (although I feel its very good to know of the http://magnetic-declination.com/). I think the MK electronics are personally very finky in terms of compass calibration. Also whether or not you actually calibrate for each location I think its a great idea to do a small test flight 10 feet in the air for 30 seconds to look at MK tools and the GPX file too. It can't hurt at least. Dave
One thing that you can check is while you are on the MX-20 screens. First get to this screen And then press the right hand "SET" button and the screen wil change to this With the copter setting on the ground it can help you determine if the spot you are on has affects in the ground that will effect the compass. The MAG: reading should be close to 100%. Stronger is better and anything below 90 is suspect. This is a good screen to see if things like wiring, external devices, camera, xbee's etc need to be moved around to get a higher setting. The second item compares the GPS declination data to what the copter is seeing. If this is more than 4 degrees I can almost guarantee that you are sitting over some iron and at 10 degrees delta you won't even be able to start motors. From the MK Wiki: The value may differ to start no more than 10° from the theoretical. Otherwise you can start the engines, but do not takeoff. Example, I can't take off from my front walkway. Rebar in the concrete is the cause. Move to the front yard or out into the asphalt street and no problem.
This is a VERY interesting post to read... 1. I never knew people flew like that... to me I don't fully trust all the electronics to work 100% of the time... I like being in control 2. How many people really use their compass? I haven't used it at all in almost a year. I actually have it disabled in MKTools. Ill only use PH every so often if I need to park the copter for a specific shot or something like that. Also if you are having to make a fast move to follow a car or something along those lines you can't do it with this method without the copter's boom in the shot (unless your looking down a lot). I like to get a run at the subject then release the stick and let the copter "float" down then just add a touch of forward movement to keep the speed up. I think people need to make sure they can fly full manual control. If you can't and something happens your screwed... just my $.02. Josh
I agree with not trusting the electronics 100% of the time -- and, as we've seen you can be on AH and still drop out of the sky. (Sorry David....I think we should name that scenario in your honor -- what a bitch to have to deal with that!) I use the compass to drive the Copter icon on the Smart OSD, so that if/when I'm a little uncertain of copter orientation, I can just glance down and see approximately which way boom #1 is pointing. This usually happens on shots where the copter's some distance away and only 30 feet up and lost in the visual clutter of the background. But, if there's any doubt about the compass, yeah, I'd power out vertically and then see if Come Home will do its thing -- if it does, well and good, but if it goes into "head for the next county" mode then I'll do the rock the wings/dip the nose trick to infer orientation if I can't see the LEDs. So I use the "distrust but verify" strategy a far as the compass is concerned. Andy.
At the risk of plagiarizing somebody (everything worth saying has already been said, right?), allow me to propose Maller's axiom #1 for our humble profession/hobby: Electronics can make a good pilot better, a marginal pilot worse and a bad pilot quit.
See: http://forum.freeflysystems.com/ind...c8-qc3228-motor-would-not-start.123/#post-999 To paraphrase you and combine with Adam Osborne's Law (he of Osborne Computing): Electronics explains why constants aren't and variables won't. Andy.
This is a video that that American airlines put together, a while back called "children of the magenta". Almost every airline or military transport pilot has seen this. It is pretty much about this subject. Of course it relates to flying multi engine jets but the principles are the same. The title is in reference to modern glass cockpits with magenta arcs. It touches on how pilots have become too reliant on the automation and that they have gotten themselves into situations that they would not have under the old systems flying jets with the " steam gauges" in the cockpit. Automation is a great tool to enhance SA and relive work load but should never be the replacement to flying the plane.
I will echo everyone's comments here, I'm a bit late to this thread but there are no shortcuts when it come to piloting one of these machines. Shaun thanks so much for posting this video.