BENCH TESTING OF THE GRAYSON HOBBY SUPER MEGAJET V2 (SMJV2)

Just finished up testing another motor, the Grayson Hobby Super MegaJet V2http://www.graysonhobby.com/catalog/ghsupermegajetv2brushlessoutrunnermotor-p-585.html

Initially I was only going to test it on the 6x4 APC, but decided to test it on the 6x3 and 6x4 EMPs as well since the 6x3 EMP has been giving me great results on some of the other motors. I used a Turnigy Plush 40A ESC and 3S batteries, but with a 45-90C discharge as these would be the 2200 Mah batteries I would put in a plane if I was to use this motor.

6x4 APC prop at 50% throttle -

• ESC at low setting - 14.9A/178.8W/478 gr/16.9 oz of thrust;
• ESC at medium setting - 15.5A/186.7W/530 gr/18.7 oz of thrust; and
• ESC at high setting - 15.9A/195.2W/540 gr/19.1 oz of thrust.

6x4 APC prop at 100% throttle -

• ESC at low setting - 26.9A/313W/770 gr/27.2 oz of thrust;
• ESC at medium setting - 29.5A/342.8W/870gr/30.7 oz of thrust; and
• ESC at high setting - 31.2A/376.6W/880 gr/31 oz of thrust.

6x3 EMP prop at 50% throttle -

• ESC at low setting - 13.2A/152.4W/508 gr/17.9 oz of thrust;
• ESC at medium setting - 14.3A/174.4W/590 gr/20.8 oz of thrust; and
• ESC at high setting - 14.8A/183.6W/610 gr/21.5 oz of thrust.

6x3 EMP prop at 100% throttle -

• ESC at low setting - 23.8A/285.4W/848 gr/29.9 oz of thrust;
• ESC at medium setting - 27.7A/328.1W/1030 gr/36.3 oz of thrust; and
• ESC at high setting - 27.7A/325W/1030 gr/36.3 oz of thrust.

6x4 EMP prop at 50% throttle -

• ESC at low setting - 17.2A/212W/530 gr/18.7 oz of thrust;
• ESC at medium setting - 15.4A/178.4W/454 gr/16 oz of thrust; and
• ESC at high setting - 16.2A/198W/520 gr/18.3 oz of thrust.

6x4 EMP prop at 100% throttle -

• ESC at low setting - 31.8A/385.4W/860 gr/30.3 oz of thrust;
• ESC at medium setting - 29.4A/320W/780 gr/27.5 oz of thrust; and
• ESC at high setting - 33A/378.8W/890 gr/31.4 oz of thrust.

As strange as it may seem, based on the numbers I tested yesterday on the SMJV2, it seems like the best performance would again be from the 6x3 EMP prop, that seems to be a very successful prop among the motors I have tested thus far. I am excited to put one on my plane (I still have the SMJV2 in my lightweight F18) and take it to the field for some more testing.

Anyway, going by the numbers I got in testing yesterday, the best results and the one I would put in my plane. Based on the quite low amp draw that I got, I may also try putting a 30A ESC in the plane to lighten the load a bit. The highest amp draw I saw for the setup I am looking at is 27.6, so I think my Turnigy Plush 30A ESC should be able to handle that.

I worked out some more numbers comparing thrust produced versus weight added by the motor and thrust produced versus amps drawn. The SMJV2 I have with prop, X mount and bullet connectors attached ready to go in the plane weighs 91 gr/3.2 oz.

Based on numbers I collected yesterday, this is the setup I would use, your numbers and preference may differ -

• prop I would use - 6x3 EMP;
• ESC timing I would use - high;
• at 50% throttle, this setup gives me 14.8A/183.6W/610 gr/21.5 oz of thrust;
• at 100% throttle, this setup gives me 27.6A/325W/1030 gr/36.3 oz of thrust;
• at 50% throttle, my thrust to motor weight ratio is 6.7:1 and my thrust is 1.5 oz of thrust per amp drawn; and
• at 100% throttle, my thrust to motor weight ratio is 11.3:1 and my thrust to amps drawn is 1.3 oz per amp.

Again, I am going to have to test this out some more at the field to see what happens with my plane, I am surprised by these lower numbers for a motor of this size, it actually seems very efficient with this setup. 

The next most efficient setup would be with the 6x4 APC prop at high ESC timing, but the high end thrust does not seem to be as good as I would have expected. The 6x4 EMP prop does not seem to be a very efficient prop for this motor at any timing setting.

Cheers,

Scott