Product Review ** DJI 1552 Folding Propeller

[Droider]

Pucker work and thanks for sharing. I did whiteness a maiden of a S1000 the other day, I can't believe those soft plastic props could possibly be so efficient.
They look and feel totally naff and way to flexible for my liking but your tests proof me wrong.. I would have thought they have to be safer than a ridged prop, maybe something could be used to see what damage is inflicted by both props a full throttle, I am guessing the ridged has to do more damage.

GREAT REVEIW.

Dave

Here is an update that includes the recently released T-Motor 15-inch folding prop. These new props come with mounting brackets that are the same dimensions as used by DJI's folding props, and mount easily to the S800 Evo and S1000 motors, as well as to T-Motor's own compatible motors.

In sum, the T-Motor folder is inferior to DJI's 1552 folding design. It is no better at low throttle settings and substantially worse at higher throttle. The T-Motor folder is comparable to the original DJI Evo prop in both appearance and function. It is a better than the original Evo prop at lower throttle and worse at higher throttle. As with DJI's folders, the T-Motor folding prop's vibration characteristics are markedly inferior to a one-piece design.

Flyers using 15-inch props and who desire a folding design should stick with DJI's 1552s on the S800 Evo and S1000 platforms. On other platforms, the T-Motor folders are fine props, but not up to the standard set by DJI with its 1552 design. Like all folders measured here, the new T-Motor folders are inferior to T-Motor's very impressive one-piece carbon fiber prop.

Updated photo/charts follow:

 

[Mojave]

List of materials for test and cost

Econfly - what is the list of materials that is needed to conduct a test like you have done? And what is the approximate cost. This was a great review - thanks!

 

[econfly]

Econfly - what is the list of materials that is needed to conduct a test like you have done? And what is the approximate cost. This was a great review - thanks!

Thanks. If you look at that pic in the review showing the bench setup you can see the equipment I used. The main item is a thrust meter. You can build one. I have one I purchased a while back. You also need a way to measure power consumption, and any multimeter would do (you might need a current shunt depending on the level of amps you will be measuring -- you can make that too). Other than that, it's just a matter of settings things up and calibrating to make sure measurements are consistent.

The vibration testing was pretty ad-hoc, and there are a lot of ways to get at it (and no single way to get it right).

Cost could be as low as around $100 to a few hundred dollars depending on how you set it up. Assuming you have basic tools and supplies (soldering station, wire, any necessary connectors, a multimeter, etc.), then you really just need a thrust meter. Here is the one I have:

http://www.singahobby.com/?q=node/13499

It works, and mine came with reasonably accurate calibration. I'm planning on building a better one. The main improvement I would like is to have the strain gauge output feed to a logging multimeter for easy analysis.

 

[Burntpixel]

Thanks. If you look at that pic in the review showing the bench setup you can see the equipment I used. The main item is a thrust meter. You can build one. I have one I purchased a while back. You also need a way to measure power consumption, and any multimeter would do (you might need a current shunt depending on the level of amps you will be measuring -- you can make that too). Other than that, it's just a matter of settings things up and calibrating to make sure measurements are consistent.

The vibration testing was pretty ad-hoc, and there are a lot of ways to get at it (and no single way to get it right).

Cost could be as low as around $100 to a few hundred dollars depending on how you set it up. Assuming you have basic tools and supplies (soldering station, wire, any necessary connectors, a multimeter, etc.), then you really just need a thrust meter. Here is the one I have:

http://www.singahobby.com/?q=node/13499

It works, and mine came with reasonably accurate calibration. I'm planning on building a better one. The main improvement I would like is to have the strain gauge output feed to a logging multimeter for easy analysis.

Very nice write up econfly. I have a question and it relates to the proper manner in which the DJI 1552 props are torqued. I am specifically talking about the screws that go through the props. DJI states in the EVO literature that POINT 4 ( .4 ) Newton Meters is the proper tightness. How do you judge what is and isn't tight in regard to the 1552 props?

I am using a .2 to 1.2 Newton meter torque screw driver to torque mine evenly after applying medium blue loctite to the screws threads,then adding a white token on the side of the screws head to denote any backing out of the screw before and after any flight. I understand that a too loose 1552 can actually flop around on arming the motors which in turn can make them actually hit the motors bell. Not a good thing in my opinion. Then again,if the 1552 props are too tight,they may not constantly spread out evenly during flight,which in turn can cause vibrations in your video footage.

Any thoughts on this matter would be greatly appreciated.

 

[econfly]

Very nice write up econfly. I have a question and it relates to the proper manner in which the DJI 1552 props are torqued. I am specifically talking about the screws that go through the props. DJI states in the EVO literature that POINT 4 ( .4 ) Newton Meters is the proper tightness. How do you judge what is and isn't tight in regard to the 1552 props?

I am using a .2 to 1.2 torque screw driver to toque mine,then adding a white token on the side of the screws head to denote any backing out of the screw before and after any flight. I understand that a too loose 1552 can actually flop around on arming the motors which in turn can make them actually hit the motors bell. Not a good thing in my opinion. Then again,if the 1552 props are too tight,they may not constantly spread out evenly during flight,which in turn can cause vibrations in your video footage.

Any thoughts on this matter would be greatly appreciated.

I think the best you can do is to adjust the tightness by feel and trial/error. I have mine so that there is no play or wobble in the mount, and where they rotate out with some resistance, but it is minimal. I know that's pretty vague, but I can't tell you what the tightness is in torque measurement because all of the screws have blue loctite holding them in place (absolute necessity, but the way). I pull the props out before starting the motors, which I know is probably not necessary, but it does avoid that initial imbalance. I think there is a reasonable range that will work, so I wouldn't worry about it too much -- tight enough to keep the prop aligned in the mount, loose enough to allow fairly easy rotation, with thread lock to keep the screws in place.

 

[Serena Alexda]

Thank you, that's interesting and useful.

 

[econfly]

Thank you, that's interesting and useful.

Thanks. Since I wrote the original review I have continued to be impressed with DJI's 1552 folding prop. It may not be the absolute best and most efficient option, but it is an excellent design and value for the price. With mounts out there for a variety of motors (e.g., from KDE) I think the DJI 1552 folder is the go-to option for a folding prop in 800-1000 sized multirotors.

 

[DLien]

Is it possible to balance these props? That might cut down on the vibrations...

 

[econfly]

Is it possible to balance these props? That might cut down on the vibrations...

Yes. But I found them to be very well balanced and paired by DJI. So while you can balance them just like any two piece prop, the other sources of imbalance are probably just as important (e.g., motor, prop mount, and even screws). In practice I just mount them as they are paired by DJI without any modifications.

 

[Arsui]

nice work.

 

[LoganJ13]

Great info. I just left a message on your profile as well. Any chance you could post or send me the thrust to current draw data? I am considering upgrading to these motors on my 810mm Y6 and would just like to have some comprehensive knowledge of the the current at specific thrust amounts

 

[econfly]

Here is power consumption for given levels of thrust. I used a DJI 4114 400v Motor and Tiger Motor 40A ESC. Tests were at 22.2v. Columns are:

1. Thrust (kg)
2. Watts: Original S800 Folder
3. Watts: 1552 Folding Prop
4. Watts: Tiger Motor 15" prop
5. Watts: Tiger Motor Folder

0.50      46.0      47.1      48.1      43.7
0.55      52.0      53.6      53.3      51.4
0.60      58.3      60.0      58.6      58.9
0.65      65.0      66.5      64.1      66.0
0.70      72.0      72.9      69.8      72.9
0.75      79.3      79.4      75.6      79.7
0.80      86.8      85.9      81.5      86.4
0.85      94.5      92.5      87.5      93.1
0.90      102.4      99.1      93.6      99.8
0.95      110.5      105.9      99.8      106.5
1.00      118.8      112.7      106.2      113.4
1.05      127.3      119.7      112.6      120.4
1.10      135.9      126.7      119.2      127.7
1.15      144.6      134.0      125.8      135.2
1.20      153.4      141.4      132.6      142.9
1.25      162.3      148.9      139.5      150.9
1.30      171.3      156.6      146.5      159.2
1.35      180.3      164.6      153.6      167.9
1.40      189.5      172.7      161.0      176.8
1.45      198.7      181.0      168.4      186.2
1.50      208.0      189.6      176.1      195.9
1.55      217.3      198.3      183.9      205.9
1.60      226.7      207.3      192.0      216.3
1.65      236.2      216.6      200.3      227.0
1.70      245.7      226.0      208.8      238.1
1.75      255.2      235.8      217.6      249.4
1.80      264.8      245.8      226.8      261.1
1.85      274.5      256.0      236.2      273.1
1.90      284.3      266.5      246.0      285.3
1.95      294.1      277.3      256.2      297.7
2.00      304.0      288.3      266.8      310.4
2.05      314.0      299.6      277.8      323.1
2.10      324.1      311.2      289.3      336.0
2.15      334.3      323.0      301.3      348.9
2.20      344.6      335.1      313.9      361.9
2.25      355.1      347.4      327.1      374.8
2.30      365.8      360.1      340.9      387.6
2.35      376.6      373.0      355.3      400.2
2.40      387.6      386.1      370.5      412.6
2.45      398.9      399.5      386.5  na
2.50      410.3      413.2      403.2  na
2.55       na   427.1      420.8  na 
2.60      na   441.2      439.3  na
2.65      na   455.6      458.8  na
2.70      na    470.2      479.2  na
2.75       na    485.1      500.8   na

 

[LoganJ13]

Thanks a ton! You measured them at a 6S voltage, I assume that means 22.2V not 25.2V right? Thanks again

 

[econfly]

Thanks a ton! You measured them at a 6S voltage, I assume that means 22.2V not 25.2V right? Thanks again

Yes.

 

[Cameraj]

Those Dji motors , what is the equivalent in t motor for power and performance?

 

[econfly]

The 400kv MN4014 is pretty close in thrust/watt with a 15" prop.

 

[Bartman]

Rob, are you still flying folding three blade and two blade props? what's the scoop? hype or legit for the money?

 

[econfly]

Yes, still using the 1552s. That's the default setup on my S1000 and it has been my go-to bigger rig for quite a while now. Just mounted a Gremsy H3 on it this week and will post up some footage soon in the H3 thread. I've been very slowly pulling together an X8 that I plan to use these folders on as well, but haven't had much time at all to get that build done.

 

[Bartman]

i've lost track of your schedule are you in MA for the winter or MO? if it's MA then let's find a way to get together, break bread and do some flying!

 

[econfly]

MO for now. I'll check in when I get back out east.