S800 EVO prop install and stress bench test video

[Louis O'Dwyer]

Hi all,

I've nearly rebuilt my S800 EVO after my little "accident"

I put the props on with what I think is the right tightness on the bolts.

I wanted to check the ESCs under load, without having to fly it, so I used a workbench as a platform and secured the S800 to it with small bungies.
You need to be careful doing it but it works very well..
I might collect all these videos on one website...

http://youtu.be/aIlXhZUExNw

 

[ChrisViperM]

Hi Louis

Just checked your vid....I like it. :tennis:

Just one question: When you put on the thread-lock glue I saw it was the red threadlocker whicjh is normally the "strong" stuff compared to the blue "medium" screw locker.....was that on purpose since with the red glue is almost impossible to remove the screw....unless you give it a serious heating with the soldering iron....don't know if that's a good idea with the plastic washers.

Chris

 

[cfrea]

I know DJI uses the Red threadlocker by standard, but I would avoid them. It is nearly impossible to remove them. You are almost sure to strip the screws trying to remove them.

 

[Louis O'Dwyer]

Well, I bought the threadlocker in a French hardware store and the guy told me it was medium (it wasn't Loctite, it was some French brand), but maybe I have put the strong stuff on, which of course will be a pain in the *** down the line!

 

[cfrea]

Yeah that is red which is basically very hard to remove . i suggest heating it up and replacing with blue before it fully dries and sets

 

[bruce365]

Hi Louis, great video and tutorial on blade assembly. I am surprised that the screw engineering to tighten the blade screws down is so primitive. It leaves tightness as a bit of a guess as to how tight to make it.

I would have thought that with such an expensive copter the DJI engineers would have designed the blade holding screws with a shoulder that would lock down positively with just the right amount of clearance for the blades, eliminating guess work as to how tight to make the blades.
These are just my thoughts, DJI may have good reasons for their design?
Regards - bruce

 

[Carapau]

Here's another thought. I would say that you are running your batteries down a bit too low at 3.4v The ideal is to consider the batteries empty once you have used 80% of the capacity which normally ends up with an end voltage in the 3.7v/cell range. Whilst going to 3.4v will get you longer flight times it will not only shorten the life span of the batteries, but it doesn't give you much margin for error at the end of the flight- ie you have not got a lot of reserve there.

 

[Tahoe Ed]

Hi Louis, great video and tutorial on blade assembly. I am surprised that the screw engineering to tighten the blade screws down is so primitive. It leaves tightness as a bit of a guess as to how tight to make it.

I would have thought that with such an expensive copter the DJI engineers would have designed the blade holding screws with a shoulder that would lock down positively with just the right amount of clearance for the blades, eliminating guess work as to how tight to make the blades.
These are just my thoughts, DJI may have good reasons for their design?
Regards - bruce

Bruce,

The S800 is considered PRO Gear. If you have flown a single rotor Heli before you know what a proper blade install feel like. Most guys that fly the S800 have both so for them it is not an issue. It should be tight not so tight that centrifical force cannot move them into position. Or too loose that they flop.

 

[Blayne Chastain]

Also, the evo manual states a specific torque value on them. Not having a micro torque wrench went by "feel" but have since moved to one piece props - simple, proven and less points of failure.

Bruce,

The S800 is considered PRO Gear. If you have flown a single rotor Heli before you know what a proper blade install feel like. Most guys that fly the S800 have both so for them it is not an issue. It should be tight not so tight that centrifical force cannot move them into position. Or too loose that they flop.

 

[boranup]

Hi Blayne are you running traditional props on your Evo now? no issues with fitment?

 

[deluge2]

Can you share specifics of what props you're using and what parts were required to adapt them to the EVO motor mounts? A picture or two would be of great interest, too!

Thanks,
Steve

Also, the evo manual states a specific torque value on them. Not having a micro torque wrench went by "feel" but have since moved to one piece props - simple, proven and less points of failure.

 

[Blayne Chastain]

Just using the 1 piece DJI props. See pic. Did have to drill out the center hole in the prop just a hair.

 

[Louis O'Dwyer]

Hi Blayne, looks good.. is that circular metal disk on top a standard S800 fitting? And what is that gold band on your heat sink?
Cheers, Louis

 

[Louis O'Dwyer]

Here's my second stress test with some more tips about safety..

http://youtu.be/G2blGwtVcmU

After all the stress testing, a half-hour's worth, I took the S800 out this morning for a test flight and I am still having an issue, I think with the same ESC that was acting up earlier.
The craft was quite unstable and every ten seconds or so the No. 2 arm would suddenly dip, then recover. Everything else, FC, IMU etc was fine, but I am grounded until I get a new ESC.
I saw a French company, StudioSport, now have EVO arm assemblies, so I bought one of those, just for the ESC, but I suppose I have a spare set of props and a spare arm.

Here's another little video of a repair job to one of the h-frame arms (with a bit of Irish diddly-i music!)

http://youtu.be/nVNcQiQZtjQ

 

[soler]

Here's my second stress test with some more tips about safety..

http://youtu.be/G2blGwtVcmU

After all the stress testing, a half-hour's worth, I took the S800 out this morning for a test flight and I am still having an issue, I think with the same ESC that was acting up earlier.
The craft was quite unstable and every ten seconds or so the No. 2 arm would suddenly dip, then recover. Everything else, FC, IMU etc was fine, but I am grounded until I get a new ESC.
I saw a French company, StudioSport, now have EVO arm assemblies, so I bought one of those, just for the ESC, but I suppose I have a spare set of props and a spare arm.

Here's another little video of a repair job to one of the h-frame arms (with a bit of Irish diddly-i music!)

http://youtu.be/nVNcQiQZtjQ

Have you tried flexing the suspected arm? Listen for beeps from the ESC. I had a similar problem with mine where it would occasionally dip like your did until it finally stopped mid air. After closer inspection i discovered that the solder joints under the cover where the arms connect was failing. After re soldering the connection everything was working smooth again.

 

[deluge2]

Thanks very much for the picture and description. So no modification to the motor mount, just the prop itself, correct? As Louis already asked, I'm also wondering if the circular plate is a standard part that comes with the s800 non-EVO (ie non-folding) props.

I'd also be interested in how you decided to power the self-adhesive LED strips that you added. I think the strips I have require increments of 3 LEDs (ie, 3, 6, 9,...) but I might not be remembering correctly.

I also wonder whether anyone has considered using multicolor LED strips in a manner that drives them in parallel with the standard DJI WKM or A2 LED? In theory, one could place a strip or strips of such LEDs in a manner that would permit effective monitoring of FC status, regardless of craft orientation relative to the pilot. The need for this may be reduced with iOSD or direct telemetry via the transmitter, but it might still be of some use--if it's even possible.

Steve

Just using the 1 piece DJI props. See pic. Did have to drill out the center hole in the prop just a hair.

 

[deluge2]

Regarding your second question for Blayne, those are self-adhesive LED strips (available in a variety of colors, 300 LEDs on a 15 foot string for less than $20 USD). At first all I saw were the 3 LEDs on the outer surface of the heat sink. But take a closer look at Blayne's picture and you'll see that he has added long strips along one side of several arms, presumably curving around to end on the ESC in the part that's shown most clearly. You can also see the LED power leads from the central frame leading to the start of the LED strip where the arm joins the hub. This could complicate detaching the arms for transport, unless a quick connect fitting has been included at the end of each LED power lead.

Steve

Hi Blayne, looks good.. is that circular metal disk on top a standard S800 fitting? And what is that gold band on your heat sink?
Cheers, Louis

 

[Blayne Chastain]

Yep, standard prop washer. The stock s800 should work. A friend of mine gave me these however. No modifications to motor bell housing.

 

[Louis O'Dwyer]

Well, after my "accident" I had to replace 4 arms, and it was a ***** to remove the connectors from the ESC, the factory solder was really heat resistant, so in the process I think I just put too much heat on that ESC and now it is breaking down. The first time I connected it back there were occasional beeps and the red LED on the ESC would flash, but then it stopped so I thought it was OK.
It was only yesterday when I actually did a flight test that I could see it dipping ..