The Test

DAL came out with the 5040 tri-blade a couple of weeks ago, and it has finally made it’s way to the DAL US distributor. This means I finally got around to ordering a few to try out. This brings DAL’s 5 inch tri-blade prop offerings to a grand total of 3: The bullnose variant, the V2 “race” variant, and now the 5040 variant. I wanted to do an in-depth comparison of each to see if I could figure out which prop was best to use under any given situation.

The most interesting thing about the new 5040’s that I received is how similar they are to the HQprop tri-blades:

5040

DAL 5040

SKU276764-3

HQProp 5040

This doesn’t actually surprise me too much. DAL’s primary competitor in the tri-blade market is the HQprops. Despite the fact that DALs have proven to produce more thrust and can actually take a crash without shattering into a million pieces, almost all of the pros are still using the HQprops. The best reasons I can come up with are:

  1. In most of the bench tests I have seen, HQProps come ahead of the DAL offerings in efficiency.
  2. DAL props pretty much never break – they bend. Some claim that this is more prone to ruining motor shafts; it also makes you more likely to fly an unbalanced prop.

Interestingly, it looks like both of these concerns have been addressed with the DAL 5040s. As you will see with the numbers below, the 5040s are the most efficient of the tri-blade by a long shot. Interestingly, they also break! I can count on one hand how many DAL props I have broken over the last few months since the first tri-blades were released, and I broke a blade off of these new 5040s on my second crash. Granted – they still are far more durable than the HQprops.

broken_prop

Oh, the humanity

I also threw DAL’s new 6045 tri-blade prop into this test for comparison purposes as well: I am planning on using these on a future build and wanted to see how they stacked up.

To test the props, I used HobbyKing’s Turnigy thrust test stand, which is the same used in a lot of other bench tests out there, such as those on QuadMcFly’s excellent miniquad testbench. I used 3 motors: a Cobra 2100kV, a RCX v2 2350kV, and a RCX v2 2633kV. For all the tests, I used only one ESC: a littlebee 30A, which was run on bone-stock multicopter BL Heli settings.

I did all 12 tests during the same day, within about an hour and a half. They were performed at my home in Tehachapi, at around 4000ft altitude. Before each motor changeout, I re-charged the 4-cell battery I was using, which is an extremely large 5800kV Turnigy nanotech rated for 45C. After each motor changeout, all four props were tested in order.

Each prop test consisted of:

  1. Spinning up the motor to full throttle and holding it there for 5 seconds, then recording the thrust and power at that point. In a few tests the motor couldn’t handle the prop and the test was aborted. In a few others, it was right on the edge & exceeding the Littlebees 30A rating, so I opted to not hold it for 5 seconds, these have been noted as such with an asterisk in the tables below.
  2. Each prop was to run it up so that it was generating 150g of thrust. The power required to maintain that thrust was then recorded. A test of this nature is probably the best way to measure the efficiency of a prop/motor combination as efficiency always drops as thrust goes up, so props producing more thrust will inherently seem less efficient than they really are when comparing only maximum thrust efficiency.

 

Results

RCX 2633kV
[table “” not found /]
RCX 2350kV
Prop Max Thrust(g) Max Power(W) Max Power Efficiency (g/W) Power @ 150g Thrust Static Thrust Efficiency (g/W)
5040 666 260 2.562 38.6 3.886
5045 Bullnose* 740 440 1.682 40.4 3.713
5045v2 700 343 2.041 37 4.054
6045* 940 510 1.843 31 4.8371
Cobra 2100kV
Prop Max Thrust(g) Max Power(W) Max Power Efficiency (g/W) Power @ 150g Thrust Static Thrust Efficiency (g/W)
5040 686 240 2.858 35.8 4.19
5045 Bullnose 1040 453 2.296 36.8 4.076
5045v2 900 350 2.571 34.5 4.348
6045 1250 505 2.475 28.4 5.282

As you can see, each of the 3 5″ props actually has it’s own niche. I’ve broken out a summary below:

If you have a strong or lower kV motor and want thrust: Pick the 5045 Bullnose
If you are using a 2300kV motor with a 20A or less ESC: Pick the 5045v2
If you are trying out a higher kV motor or want your prop to be able to break: Pick the 5040
If you have a smaller ESC or want to be generally conservative: Pick the 5040
If you want to use the best all around prop: Pick the 5045v2

Footnote on the DAL6045s

So it’s been a few weeks since I wrote this article, and I finally got off my butt an installed my DAL 6045 tri-blades on my Krieger with the 6″ arms. I have to say, I’m pretty damned disappointed. They have some sort of issue with the plastic or molding that causes them to oscillate at extremely high frequency when driven to certain low RPMs. This oscillation causes vibrations which cause a tuned flight controller to freak out and cause a crash, and the problem occurs constantly while flying in acro mode. Unless I have a bad batch, I would recommend you stay away from these. I have never had this problem with my DAL 5″ props.

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