So in craving more and more power and speed from my modified Hawk Sky's that I have put together over the past few months, I decided to once again go up a size in the Grayzon hobby line of motors, to their largest motor in the "jet" series of motors they offer. The Monsterjet is a 2400KV motor that is a tremendous performer. The specs of the Monsterjet from the Grayson website:
Specs
No. of cells 3 S Li-Poly
RPM/V 2400 RMP/V and
Max. efficiency 80%
Max. efficiency current 20 - 45 A (>75%)
No load current / 6 V 4,5 A
Max Current capacity 55 A/60 s
Internal Resistance 22 mohm
Dimensions (diameter. x length) 35x37 mm
Shaft diameter 4 mm
Weight with cables 106 g
The airframe
One of the most obvious and easiest things with the Hawk Sky is to cut the wings down to increase performance in both speed and maneuverability. The measurement that I use is to cut all the length of the wingtips from 1" outside of the outermost control surface notch. So roughly you are left with 1" of wingspan past your control surface. This measurement seems to work very well in building the performance of the Hawk for bigger and faster motors.
I also cut the length of the horizontal stabilizer from 1/4" outside of the elevator control surface on both sides. I always add hotglue to all of the connectors of the pushrods and connectors to the control surfaces for added strength. Also, once I get everything setup and tested with the ailerons, I hot glue in the wings for a more permanent application and strength. Most foam planes get loose when it comes to the wings after several flights due to the normal flexing and stress that the airframe is subjected to with high G maneuvers.
Motor, ESC, and Prop
As mentioned above, the "Monster" Hawk is configured with a Monsterjet 2400KV motor from Grayson Hobby. I also picked up the 70 Amp ESC from Grayson as well. That ESC is a little overkill but I want to have the headroom for 4-cell applications as well. Max current capacity on the monsterjet is 55A/60 s, but the 70 will once again give us room to play. Grayson does not rate the Monsterjet at 4-cell, however, you can find numerous videos of ones who have ran 4-cells with the Monsterjet without any issues, as long as you take heating into consideration as well as the termperature of the day. Obviously, you can get away with more heating on a cold day than on a blistering hot summer day.
The prop is an APC 6x5.5 prop that works very well on this application. With the location of the prop on the Hawk, a 6 inch prop is the max length you can do without either modifying the motor mount for more height or cutting a notch in the backside of the tail section. This is what I have done in the past and seems to work pretty well as long as you add support to the tail section to accommodate the missing notch. However, for me since I am setting this up for 4-cell in addition to 3-cell, the 6x5.5 is about the max you can go with 4-cells, so I am going to keep the 6x5.5 in place.
