Crashed today...

I will take a guess and say that it sounds like you calibrated in an area with interference. Then lifted off. Compass error. P3 switched over to ATTI which means it won't hold position which is why it continued going toward and eventually hit the tree. Just a guess. I'm sure the pros will be able to come up with a better explanation when they get your flight data.
 
[QUOTE="phantom1972, post: 682245, member: 37374" But later, idling on my coffee table, an exponentially growing vibration started, right out of the blue! .[/QUOTE]

Tesla would have been proud :)
 
I will take a guess and say that it sounds like you calibrated in an area with interference. Then lifted off. Compass error. P3 switched over to ATTI which means it won't hold position which is why it continued going toward and eventually hit the tree. Just a guess. I'm sure the pros will be able to come up with a better explanation when they get your flight data.

I feel you are correct. I assume something like this is not covered under the warrantee?
 
No, the props were literally spun down on the shafts, and that's as tight as they were when I took off. The props ARE self tightening, but they they need to be snuged tighter than not at all! The oscillation stopped the instant I firmly touch one of the gear legs. CLASSIC RESONANT CONDITION. I damped it out, saw my props were loose, and never had the problem again. And I now use my checklist. Which includes compass calibration if needed, or suspected of being needed.
 
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There was no damage. No warranty needed. The no prop tightening, caused warning messages that I tracked back to a resonance amplified oscillation, set up by the loose props. And discovered in the coffee table at idle.

The tree is a different subject. I did hit a Pine Tree, and almost killed myself climbing it. But it was a CLASSIC error that DJI is trying to fix with the P4. I was in "follow me mode"! And it was following me perfect! So faithful it was going to go right through that Pine Tree to stay with me. Only it got stuck. Right near the top, and it was TALL. I ended up dropping it into some grass, and did the same to me -- From lower even (Still 10', flat on my back... OUCH). The P3P sustained no damage, but I did. Broken pelvis. That P3P now has loads more hours in it. STURDY BIRDS. NO DAMAGE, NO REPAIRS. I did recalibrate the IMU.

P4 ads have some epic follow me disasters. Not a shadow of a doubt. It operated exactly as designed. My brain malfunctioned.
 
I have lots of hours flying the P3P by now. I'm acutely aware of both the importance of the compass calibration, and the need to verify the compass sensor reading also, to make sure you got a reasonable cal. I'm always in the 1300 - 1500 range. Once it's calibrated, you're not out of danger. I tried landing in some heavily rebar reinforced concrete, and got some wild behavior. I didn't know about the rebar.

I love to show people Atti mode when there is a stiff breeze blowing. GPS has it hovering like a rock, traveling in straight lines... I like to have it hovering and show them what happens in atti mode. It would drift out of sight in 30 seconds. Put GPS Mode back on, and it locks it back in place. Impresses the hell out of people.

I've probably been lax on IMU calibration, but now follow the general consensus. I calibrated it after my hard impact, even though the "Check IMU" said things were OK.

The special flight modes are awesome. One could be very handy if you were to lose the video feed. I find flying by FPV a piece of cake, orientation wise. Hitting things you have to be careful of. Power line will get you.

But flying by sight only, the bird doesn't have to get far away before the symmetry works against you. Even returning it to you can be a *****. The "Home Mode" is a viable alternative to RTH. In this mode, pull back on the pitch, and it will come to you. I even returned with full yaw, so the thing was making a bee line right towards me, while rotating like a top. Amazing. Follow me is great, but don't let the bird follow you into disaster! I've heard of people walking beneath a tree with a canopy that wasn't going to work. LOL. The point of interest mode works great. The constant heading mode, while varying the yaw angle gets shots with ease, that could be duplicated without it, but only with a lot of skill and finesse. I've only played with the way point function a little.

I've been lucky, because all those hours taught me lots of lessons, some the very hard way, but I haven't needed any repairs. Except for props. I'll replace a prop if it's not PERFECT. TOTALLY PERFECT. A failure there is GAME OVER.

Any error I've described and the cause are 100% accurate. Mostly because they were obvious, but also because I've made a lot of the classic mistakes already, and read these forums constantly. And seen some great tips.

I love the one about the guy who flew through his open house door, lost his remote signal and had the bird execute an RTH in his living room. Trying to climb to 100', and grinding his prop hubs on his ceiling. LOL Yes, I get great GPS reception in my living room. Single story, wood roof, but I'm still amazed. His wife was not happy.

Setting the RTH altitude too low has gotten a lot of people. That should be a checklist item. It should be conservatively high, but not ridiculously so, because you might need the battery reserve. 60 meters where I live is plenty. I do think there are a couple of cell towers higher actually though.
 
Hi Phantom 1972, thank you once again - pleased I could offer a little insight into the props when it comes to installation of them. Someone mentioned it would be helpful if DJI could offer up a torque value for the props, well as you can see when the shoulder of the prop hub hits the top of the motor frame (that abrupt limit you mentioned) you are about as tight as you are gonna get (without compressing the plastic shoulder).



Obviously and impressively you are very familiar with vibration and resonance and the importance of same. I like this statement of yours "designed to ferret out any resonant conditions inside the box (filled with circuit boards)"! That is a perfect way to explain (ferret out) with regard to identifying natural frequencies and the effect any given forcing frequency might have on a particular stationary part (boards) with respect to resonance. Hence, the "shaker tables" allow for many excitation forces to occur in order to identify resonant activity. Construction of isolation, stiffening or damping systems is then carried out at the areas of concern to eliminate or reduce the effects from damaging vibration activity.

I haven't done any "shaker testing" on the Phantom but do plan to one of these days (purely out of personal curiosity)! As is, I notice there is, at specific rpm's of the props some increased vibration at the landing gear/legs/feet. I wouldn't doubt if when looking at the flimsy (if I can put it that way) construction of them this is perhaps by design. The legs IMO work as a "dynamic vibration absorber" (neutralizer for vibration), possibly tuned into some vibration harmonics produced via different or specific rpm of the props. Hence, any vibration at those specific frequencies would be absorbed at the legs (intentionally induced vibration at the legs) which may be tuned to vibrate in such a way so as to counteract vibration forces from any rotating unbalances present from the Phantom.

i.e. residual vibration from the props etc. would excite an area of least resistance, which in this case would be the legs and away from electrical components within the Phantom.

That would be the biggest reason I would suggest not to mess with adding any physical mods to the Phantom (or any flying unit) that could have a detrimental effect on the natural frequencies present. Even the addition of those "Gimbal Guards" is a prime example of adding "stiffness" at the landing gear which will to some degree increase the natural frequency of the legs and possibly take them into an area where it negates the affect of the legs (dynamic absorber) ability to dissipate unwanted and harmful vibration activity within the bird.



Yes you would have lost your bet LOL - sadly and embarrassingly so, I was a high school drop out after 2 weeks of grade 10 (not proud of that)! For whatever reason school just wasn't for me, hands on kinda guy I guess - I do however promote higher education religiously.

I apprenticed to become a Millwright and then specialized in Vibration Analysis - the rest has been tons of reading and curiosity induced tinkering and experimenting along with every day experiences on different jobs. I do converse often with both Mechanical & Electrical Eng types with my work, admittedly however get a little annoyed with the theoretical types - show me in practice, or don't mention it - terrible attitude I know LOL!

I regret not going to College or University (or finishing high school for that matter LOL) and hold both Mechanical and Electrical Engineers to a high regard and with utmost respect.

You are a VERY intelligent person, who took what education you had, and learned what you needed on the job or on your own via curiosity and initiative. Very impressive!!

I value the engineering education I got, oddly because of one of its limitations. At the undergrad level, you're really getting a broad overview of the different subjects. A base on which to build on. But that base, especially in mechanical and software engineering I still found fascinating.

But basically everything I did at Harris as a digital circuit designer I learned in the job. ESPECIALLY] since when I started, there were no PCs, we were designing with NAND gates and flip-flops. From there to designing using HUGE Field Programmable Gate Arrays (FPGAs), designed using a special "Description language", on powerful Sun Workstations happened within an amazingly short period of time. But when I sent to school, a Sun Workstation could have only come out of an alien spacecraft.

It just wouldn't have been allowed, but you'd have succeeded fine as a EE when I started.
 
Thank you phantom1972............continue to tinker and experiment - brain food!

A couple of things I keep in mind "a sensible man knows his limitations, then tries like hell to successfully exceed them" .............and............ "around a pigs butt - is pork" - think on that one lol!

But basically everything I did at Harris as a digital circuit designer I learned in the job. ESPECIALLY] since when I started, there were no PCs, we were designing with NAND gates and flip-flops. From there to designing using HUGE Field Programmable Gate Arrays (FPGAs), designed using a special "Description language", on powerful Sun Workstations happened within an amazingly short period of time. But when I sent to school, a Sun Workstation could have only come out of an alien spacecraft.

Wow - now that is what I call impressive, almost pioneering stuff, paving the way! Sun Workstations - few and far between even back then.

But when I sent to school, a Sun Workstation could have only come out of an alien spacecraft.

That is pretty wild when you really think of it as not being that long ago - pretty solid compliment to it's developers!
 
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Thank you phantom1972............continue to tinker and experiment - brain food!

A couple of things I keep in mind "a sensible man knows his limitations, then tries like hell to successfully exceed them" .............and............ "around a pigs butt - is pork" - think on that one lol!



Wow - now that is what I call impressive, almost pioneering stuff, paving the way! Sun Workstations - few and far between even back then.



That is pretty wild when you really think of it as not being that long ago - pretty solid compliment to it's developers!

I was thinking the other day how far technology had come in the 13 years since I started at Harris (1982) to when I left (the first time) in 1994. We stated with no PCs, integrated circuits were in DIP packages, with AND gates, and Flip Flips. We drew schematics by hand, and gave them to drafting. The complexity of our circuit boards (simple), and the manpower (lots) to do it with was laughable. When I left (The first time), we were designing big Field Programmable Gate Arrays on Sun Workstations, with powerful simulation hardware. A single FPGA could replace one of our old boxes. A QUANTUM LEAP.

Everyone had a PC in their office. You first had to be important to get one. Then important NOT to get one. LOL

After 7 years of working for a hedge fund, which blew up :-(, I want back to Harris. In 2000? After 7 years. You'd think it should be hugely different!

It wasn't. The Sun Workstations had gotten way more powerful, and the Xilinx FOGAs got far more dense, but the process was exactly the same, and I felt like I'd never left.

What was the game changer was the increasing density of Integrated circuits. Which helped make PCs and other equipment affordable. And the Networking that flowed out of that. I'd say most of that transition was over 5 years. Then it became a game of improvements. HUGE ones, but still the same building blocks. Make memories bigger/faster, make processors faster and more powerful. And make the network pipes fatter! There is so much data being passed around now. There is no such thing as fast enough.

But with these changes, an engineer could vanish and fit right back in. Leave in 1984, come back in 1994, it would be a new world. I feel lucky to have witnessed it. I know how to work a sliderule. That's embarrassing.

Oh, happily I have a lot of hours in real planes and gliders over the years. And I think my body in there throttled me back a little. Although when you're 18, you're immortal, so it was only a LITTLE. But enough so I didn't wreck any planes or hurt myself! LOL. That's what I love about drones. You feel like you're there, there are big incentives to not hurt anything, but if you do, it's only mental anguish (pride and $$ LOL)

I'd say in my short drone career, I've lived up to your first saying PERFECTLY. Other than falling out of the tree, it was all a good, fun, harmless, learning experience.

I'm going to have to think about the pigs butt one...LOL

OH, EVERYONE agrees that being an Electrical Engineer was more fun, when it was simplistic. We didn't know how inefficient we were. That was the state of the art. When it changed to sitting in front a terminal all day, it wasn't as fun. Interesting isn't it. Hey, I have to do a pay adjustment in a constant dollar basis. EEs should be getting paid way more becsuse of efficiencies.
 
OH, EVERYONE agrees that being an Electrical Engineer was more fun, when it was simplistic.

LOL - the only simplistic part of being an EE was when one of you guys would find a willing participant then sadistically say-----

"Hey you, hold this wire"!----"Why"?------"Just hold the **** wire will ya"!----"Not a chance, I don't know what it does"-----"of course you don't, that's the experiment, now just hold the wire"---

EEs should be getting paid way more because of efficiencies

Agreed! I believe just because EE's make internal components more efficient, smaller and with more power, doesn't mean their salaries have to follow suite. Again here - "device capacitances decrease, so less power is required to drive this capacitance", translated: Electrical Engineers now become Energy Engineers which = less salary, & they get to use the same acronym EE.

Oh, happily I have a lot of hours in real planes and gliders over the years

Gliders must be totally awesome to experience - nothing but the sound of your own beating heart and the "swoosh" of the air around you.
 
Hi SteveVaus,

Using an iMac, here are the steps to access the .DAT files stored on the hidden SD card permanently mounted inside the Phantom 3.
Also see the attached photos for a clearer viewpoint.

These first four steps below are from the "Drones Made Easy" website… support.dronesmadeeasy.com/hc/en-us/articles/206171443

1. Power up everything with the Phantom 3 as if you were going to fly (except the props), and launch the DJI GO App.
Enter the camera view.

2. In the MC Settings menu, choose Advanced Settings. You can find the MC Settings on the top leftcorner of the screen,
directly to the right of the Home icon.

3. Scroll down, and select Enter flight data mode.

4. The DJI GO app will prompt you to connect the drone to a PC or Mac via the USB to mini-USB cable included with your drone package.
The mini-USB port on the Phantom 3 is located on the front or nose of the drone, (and not the camera gimbal frame).
Plug the regular USB plug directly into your Mac (not a USB extension port box).
Note: This was done using a 2013 iMac running OSX 10.8.5, there may be some differences with different models and OSX versions.

5. Once you connect the drone to your computer wait to see if by chance it does mount to your desktop.
When it doesn't, open the application Disk Utility.

6. Select the disk DJI DATA LOG. It will show listed in the left column of disks in Disk Utility.
You can select it even though it is not mounted to the desktop.
(Be sure to choose the root disk DJI DATA LOG file and not the DJI FLY LOG file).

7. When the disk DJI DATA LOG is highlighted, select the New Image icon in the top row.
This will present the dialog box shown, asking what to name it, where to save it and what format.
(I've chosen compressed with no encryption).

8. Be prepared to wait along time… The amount of time depends on how many .DAT files there are.
The entire SD card could be full. The Phantom records a .DAT file every time it is powered on,
regardless of flight or not. It only erases them when space is needed for newer files.
(I wouldn't start with the Phantom battery less than 50% charged).

9. Once the Disk Image is created on your Mac, double-click it, it will uncompress to a new window
(in temporary RAM memory only). Drag the files you want from there to a newly created folder on your computer.
That's it!

10. The FLYxx.DAT files will have considerably more recorded flight information than the
DJIFlightRecord text files that are copied from the DJI GO app.
The FLYxx.DAT files can now be analyzed for content, but how to do that is a whole different topic…

View attachment 44167 View attachment 44168 View attachment 44169 View attachment 44170


Good posting - thank you
 

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