Hey fellas,
I managed to finish the video but there's a problem I didn't count on.
I've always balanced my S800 and S1000 using the dynamic method (at least ever since I discovered that the static method wasn't good enough for those models) and has never been a problem but I can put those in full manual mode which means it doesn't use Atti or GPS.
In manual mode, you fly them with full control from the transmitter (no assistance from the flight controller at all). You can even do a flip with them as long as you have enough altitude for recovery while in manual mode (not sure why you would want to but you can).
I found out the hard way that these Inspires are a much different story. I didn't think it would be a problem except for not having precise control over the throttle range.
When I throttle it up, it goes full speed and when I bring it back to mid stick it goes idle since it never left the ground.
I disabled the VPS system and put in Atti Mode before doing the balance but the computer is still looking for it to gain altitude before it will throttle back to the normal speed for hovering and for descending or ascending. It will try as hard as it needs to to gain altitude and since it's not, it goes to full throttle.
During my last spool up, it actually hung in the full throttle position even when I brought it back to mid stick, the only time it slowed down was when I brought the throttle all the way down and even then it took much longer than normal to shut down. For a couple of seconds, I thought I was going to have to shut the battery off to get the motors to shut down.
It did throw the IMU way out of calibration. Luckily, it did do OK after I did the full IMU calibration.
After a lengthy discussion with DJI Tech Support about what happened, they confirmed that its not a good idea since the Inspire is actually tilting the wrong way.
In a high wind flight, the Inspire will tilt into the wind but in this case it's tilting the wrong way and causing the gyro and accelerometers to work against the computer's algorithms.
It may do this for a second or less in an actual flight but certainly not for an extended period of time like it is when performing a dynamic balance.
All it needs is a second or less to cycle through the PID Loops three times (each loop being less in amplitude from the previous loop and it only takes about 1/4 of a second or so to go through a single loop). The programmed algorithms tell those PID Loops how to react in normal flight as well as when a high gust of wind is encountered.
The only way to prevent this is to have the Inspire strapped down very tight and then it picks up resonance from the table which defeats the purpose and gives you a false reading in the reflected laser beam so either way, it's not good.
I figured it was flighting the IMU the first time I balanced mine but it never caused the IMU to lose it's calibration and hang at full throttle............until this time.
So, I no longer recommend using the dynamic method for balancing the Inspire props.
I sincerely apologize for promoting the dynamic method! I was wrong to do that but it was an honest mistake.
It worked and still does if you have a multirotor that has a fully manual mode such as the S800, S900 and S1000 Etc.
I do have good news though!!
DJI has done away with the conversion hub kit that was made just for the original Inspire 1. Now they are all the same. That same hub WILL work on the V2 and the Pro Model. It will work on all Inspire 1 series now.
While on the phone with DJI, we discussed that issue and they made it clear that the new hubs are made for all Inspires now.
If you'll go to DJI's website, click on the link for the STORE (big blue link at the top), then scroll down to the Inspire 1 Pro or the V2.0 model (either one), click on that, then scroll down to RECOMMENDED ACCESSORIES bar, look for a little blue link (named MORE) to the right and just above the accessories bar, click on that and it will take you to a page for the accessories, scroll down to the seventh line, the hubs are the first one on the left and it IS now made for the V2 and the Pro models as well as the original Inspire 1 series. Order just one kit cause it has one CW and one CCW complete hub set in that kit.
With this new hub set, you can accurately static balance your props if you use EJH's adapter rod.
That's it, now there is a reliable solution to static balance the 1345T props without having to remove your own hubs.
Unfortunately, I still can't find anyone willing to 3D print my design. It doesn't matter to me, I just want everyone to be able to balance their props!
BTW, Mark (the editor) was more right about the need to hold the Inspire from moving at all!! Thanks, Mark!!
One other thing you can do, is to put your Inspire into a hover and tilt your camera up to the point where you can see the props while in flight. Do a 360° rotation of the camera while having it pointed at the props. Shoot it at 60fps, then put that footage into your editing software and slow it down to 40% of it's original speed to see if there is any movement in the arms or to see if the gimbal is bouncing around (or at least moving back and forth). With the camera being that close to the props and arms, you'll notice if the camera is static or if it's moving around. This needs to be done on a calm day or the wind may cause the gimbal to move.
I've uploaded a video that I shot of my S800 after I static balanced three props and dynamic balanced the other three props. The three props that were static balanced caused the arms to flex, the others did not flex.
Keep in mind that the S800 was notorious for having arms that would flex so those props HAD to be PERFECTLY balanced to keep the arms from flexing.
The S800 EVO arms are much stronger and flex much less. The dynamic balancing method for those multirotors is much different than it is for the Inspire.
Also keep in mind that the Inspire arms themselves won't flex, however, the arms aren't fixed solid into the "T" shaped pieces that the arms are held by. There is a little play there and it will show up in a video that's been slowed down. You have to slow it down to see it. Viewing it at the normal speed is just too fast to see the movement.
I filmed my first Inspire before balancing the props to see if it was noticeable and it was. After balancing the props, there was no movement.
I didn't keep the video though, at the time it was taking up much needed external hard drive space so I deleted it.
I will film it again next time I get a set of props that need to be balanced. I'll film it again before and after balancing the props and keep the video next time.
I suggest that you film the props after a balance job just to make sure it's as balanced as it should be but that's up to you of course.
Jon,
You may have a hard time getting your 45mm lens to be really smooth. The reason I say this is because at that focal length, any tiny movements will be magnified and I'm not sure that even a set of different durometer dampers will take care of it. It may take something along the lines of the Z15 gimbal to hold a lens steady at that focal length but I could very well be wrong. You may just have to experiment with it.
Here's a link to the 1345T prop hubs for the Inspire 1, Inspire 1 V2 and the Inspire 1 Pro:
Buy Inspire 1 Series - 1345T Propeller Installation Kit | DJI Store
Order it from DJI though cause if you order it from someone else, it may be one of the early conversion kits. It has the same part number, go figure!
Here's the link to the video of my S800 filming the props while in flight:
P.S. I did verify that the likelihood of actually damaging the IMU is very, very slim unless you do it a bunch of times but in my humble opinion it's not worth the risk.
Again, if I had known that the IMU would have been at risk, I not only would
not have suggested it to you guys but I would have never done it myself.
I was worried about it so I sent mine in to be checked. I just got it back (very quick turnaround too) and they confirmed that no damage was done but it was suggested to not use the dynamic method again.
I asked if DJI was going to come up with a balancing tool for the 1345T props but they said that there were no plans for it at this time (at least as far as the tech guy knew).
Again, my sincere apologies to everyone!! It's been a learning experience for all of us with these odd shaped prop hubs.
At least now we know we can order a direct replacement hub for the V2 and the Pro models.
It would have nice if DJI had made some type of an announcement about that part. I guess they have a lot on their plates eh?
I wish I had figured this out before spending the time to make the video that isn't any good to anyone, but that's OK. At least nobody did any damage that I'm aware of.
Sincerely,
Joe