Freewing 64mm F-14 (6 cell EDF)

[Konrad]

I got this Freewing 64mm F-14 as my distraction from the family dynamics on my last visit to Denver.

Wow, Freewing has addressed most of the issues we had with the much larger and dated twin 80mm EDF F-14. The two main issues that the 64mm F-14 addresses are the structural issues with the main landing gear. And that the power system is appropriate for the mass of the model. The larger 80mm F-14 did NOT tie the main landing gear to the load bearing spreader plates. This smaller 64mm F-14 does mount the main gear to the aluminum spreader plate. The larger 80mm F-14 was way underpowered with the supplied outrunner fans trying to push 14 lbs of model. The 64mm inrunner motor do a great job motivating the smaller 7 lbs F-14! I measured 130 amp from a 6 cell 5900 mAh SMC HV battery pack. I was a bit surprised at this current draw, being that I was a 7K feet. Note this is a bit of a concern as the ESC are only rather at 60 amp (2 x 60=120amps limit). I saw that the spec sheet for the Freewing power system list the current for the EDF units as 65amps. I have some concern about the mis-match between the spec’s and actual readings. (It is interesting to see that the dual 64mm power plants are stressing the batteries about the same amount as the single WeMoTec fan I have in my 80mm F-14. This is to say that the 64mm f-14 needs high power low IR batteries).

Based on the MotionRC recommendation to use the 750 gram Admiral 5000 battery I chose the 740 gram SMC 5900 HV battery. Based on only 2 flight it appears that the 750 gram battery is a too heavy as the model flies as it she is nose heavy. I love the added duration and power of the SMC 5900 HV cells. But it looks like I’ll need to add a 25 to 50 grams of tail weight to reach proper trim.

I want to be clear, I love this little 64mm F-14, but it is still a Freewing product!  This means one needs to be very vigilant with the assembly and maintenance of the model! First is the quality of the servos are sub par! Straight out of the box I had 2 failed 9 gram servos (one was a rudder and the other was an aileron)! These failures were traced to pushed back pins in the connectors. The problem was that the pins where installed rotated 90° so that the retention feature was made inoperative. Luckily this was easy to fix. No need to dig out the servo with the usual foam damage! I’m sorry to say that Freewing models still have a servo failure rate of around 20% prior to any flights. This is unacceptable! Please perform a 5 minute burn in of all servos prior to flight! Based solely on my experience with the Freewing brand servo I replace the tailevon servos with Hitec 5085 as I had a set available. These fit the pocket perfect. Now they are a bit of over kill as I use these 5085 servos in many of my 90mm jets.

The other flight issue was that the leading edge of the wings had a very pronounced mold line. This mold line will disrupt the airflow coming around from under the wing at high angels of attack. This is a real problem on ladings. My solution was to sand off this molding flash with 320 grit sandpaper.  This is again a typical problem with Freewing models, that is they don’t prep the model prior to painting. This is more than just a cosmetic issue.

The last real integration problem I had was with the gyro/wiring board! I couldn’t find the Blue Tooth Bridge to interface with the board and gyro app on my phone. Also Freewing has the gear sequencing running far too slowly. There is no excuse having to wait 12 seconds for the landing gear to cycle!

Now to flight performance. Like I said I love the flight performance over the stock 80mm F-14 in all areas. I actually like this little 64mm over that of my re-fanned 80mm F-14 as it actually has a longer flight duration. (I only use full power with the 64mm F-14 going in the vertical). Now compared to my Arrows Mig-29 with similar power units, other than the batteries (4400 mAh verses 5900 mAh cells), the 64mm Mig-29 does out perform the 64mm F-14. I think this can be traced to the weight.

The Mig -29 took a bit of work to get her to perform as I would like. The Freewing F-14 met most of my performance goals straight out of the box. At USD $500 she is not a low value model. At this price point I’d have liked to see more effort in the prep of the parts prior to assembly. I’d also like to see Freewing move up to a higher quality servo. I almost alway upgrade my flight servos to E-Max 9 gram servo.