Eagle Racing MD2 Motor Dyno
 

I figured it was time to start up a thread on the MD2 Dyno.

Information can be found in the web link below. Well... Kinda. It's all in Japanese. However, here is some information.

Power input ：DC 6.6-7.2 V 2x Li-Fe or Li-Po or Ni-MH or NI-CD ）

Case size: 125 x 117 x 90 mm
Weight ：391.7g
Motor mount size: 100 x 90 x 70 mm
Motor mount weight ：315.5g
Optional motor size: 380, 540,550
Flywheel size: 40 x 12.7 mm
Flywheel weight: 118 * This weight will vary from flywheel to flywheel.
Flywheel shaft diameter: Φ 3.175
Maximum motor size is 13.5 brushless. Don't even bother with anything faster than that.

http://www.eaglemodel.com/jp-net/menu-jp.html

I've done a series of videos on this dyno.

Part 1 (What comes with it and so on)

https://www.youtube.com/watch?v=VJmENIUz6MY

Part 2 (Setup and motor run)

https://www.youtube.com/watch?v=o6sKZdyh3_s

Part 3 (Extracting the dyno information onto your computer)

https://www.youtube.com/watch?v=4JYdeWZFokc

Part 4 (Flywheel Dyno Analysis using RC CREW CHIEF) (From RC CREW CHIEF YouTube Channel)

https://www.youtube.com/watch?v=tEVG...WIKDeR5bO8LXd-

Part 5 ( Importing Motor Models from RC CREW CHEIF website into RC CREW CHIEF program) (From RC CREW CHIEF YouTube Channel)

https://www.youtube.com/watch?v=4smo...WIKDeR5bO8LXd-

Looks good but how can those of us in other places get a hold of one?

Thanks Ed. I have been holding off ordering one of these because I didn't know if I could use it with no instructions.

On the video you say to use 2 * lipos to run it, or there is an issue blowing fuses on a single Lipo. Will I get this issue if I use dc input? (using my Graupner charger's 5A PSU to power it on 12V)

I found mine very easy to use and managed to work out how to use it without the instructions. Eds videos are very clear which should resolve any concerns.

The software interface is pretty basic and can be a pain to find the right com port but once working it is quick to upload data of back to back runs into the computer.

You can graph the data in excel but I found RC Crew Chief is excellent to analyse the data has been extremely helpful for tuning motors.

Md2 Dyno
 

Good unit. I had one but sold it to a friend before using it.

We tested Kill shot, D4, D4 RPM, R1 UPv7 and V9, TP Actinium, LRP X20 and Gforce. All had varied but overall similar results.
It uses an optical sensor and a balanced flywheel to calculate acceleration and rpm. From this it calculates torque and power. It maxes out at about 30,000rpm which is ok as all 13.5 motors produce max power below this anyway.
A handy tool for those that think it's necessary. Much better than a motor checker. Make sure you have a good power supply or fesh batteries between each test. I got mine from Eagle Models online store. Paid with PayPal, shipped out within a day and customer support emailed me a photo of the EMS freight docket/tracking number.
http://www.broadtech.hk/eagleshop/shop/ShopProduct.aspx?type=Search&keyword=Md2

You can download the instructions from their website. There are some attempts to mix english within the content of the instructions but I think some of the information is missed in the conversion. You're still able to work thru it though.

I have run mine with a single lipo exclussively and haven't run into any issues. :confused: I don't think that power supply has enough current for the spike.

RC Crew Chief really makes this dyno worthwhile, makes a nice complete package of information.


I bought mine off of Amazon. it had free shipping and I got it in about 2 weeks with no issues. If I had one complaint, I would like to see the flywheel better packed as my optic wheel was slightly bent when I got mine. I straightened it out, but would have prefered it flat out of the box.

I have had one of these for a while now. I too run it using a single lipo, charging between runs (lets you test your batteries as part of your powertrain). Simply running back-to-back testing using two identical batteries will tell you what power loss you (if any) you are seeing with your batteries - if the power and torque numbers increase significantly using parallel batteries, then maybe its time to upgrade.

You would need a stout power supply to feed the main input - I have seen spikes of 80+ amps only testing 17.5's.

The unit provides some useful data, but I have found that same-motor testing for repeatability yields a variance on the order of 2%.

The dyno has the ability to run brushed motors off the internal esc - I have only used this with silvercans and Tamiya sport tuned motors. Based on the current spike, I would be hesitant to run anything faster than a 27t open endbell motor.

Using the external ESC option takes a minute to figure out - you need to manually test the esc without the flywheel attached, starting by adjusting the pulse width (in milliseconds) so that the esc initializes at the neutral point and then step up the pulse width to find the point where max throttle is achieved. Then you save the settings. This process should be re-done each time you test a different esc. I have found that the high point being set too high for a different esc resulted in the unit not running a motor test.

I have an RC Crewchief license and so I make motor models for my personal use, however this requires curve fitting data so the motor models created are only approximations of the data recorded by the dyno.

Comparing data directly in MSExcel is the best method to avoid approximation, however this method is not without challenges.

In the end, the results of this unit closely approximates the flywheel dyno I built previously, which uses a computer-based DAQ card to process input data at a much higher frequency. If you have a motor that is putting out about 5% less power and torque, as calculated from the machine, I would call that a significant difference.

So what is the cost? I couldn't find it on their website.

ESC Calibration
 

A tip for calibrating the ESC.

Calibrating the ESC to the dyno can be a pain depending on your ESC as there is no brake signal and some ESCs are not happy about this.

I found the easiest way to get around this was to set the radio throttle EPA adjustment set to 80% then calibrate the ESC to the radio as per normal. After doing this the ESC will be set to the same pulse width of the dyno.

Double check the ESC is reaching full throttle to make sure but it has worked perfectly with LRP, SP HW ESCs I have tried.

OK I found it. It costs $110.00 and $41.00 for shipping to the US.

Yep I just ordered one yesterday, and am going to grab a cheap xcar esc to have permanently wired to the dyno. (Edward offered to source one a bit cheaper but wanted paypal gift upfront which I wasn't comfortable with)

Each to their own, I guess. :weird:

Sorry Nexxus, I didn't fully read your post. The 12v DC input on the side of the dyno is only to power the on-board computer - it has nothing to do with supplying power to the motor that you are running. On my PS, it shows to draw about 300 mA.

I have had my unit apart - I can confirm that the battery inputs (main power input) are fused separately. Testing 17.5 and 21.5 motors, I have seen spikes of over 80 amps, which with a single slo-blow ATO style fuses is just fine (from the time-current spec for a single 35 amp ATO fuse, it will handle about 200 amps continuously for 0.1 sec, which is 5 consecutive dyno readings) .

Awww....