FPV FunJet Project
The Multiplex FunJet has become extremely popular with FPV pilots
looking for speed. The FunJet has been clocked at over 100mph with a
hopped up set ups.I'm not a big fan of pusher prop jets and prefer EDF jets but the speed and ease of building I felt I had to give it a try. I
purchased the FunJet and opened the box and was surprised just how easy
it looked to build. And I was right this little jet goes together in
less then an hour and was very easy to put together. It has a large
fuselage inside which allows easy placement of all the FPV gear which
also explains why FPV pilots have given it good reviews.
with attaching the rear motor canopy and I only glued it in a few spots
so it would be easy to remove if I need to access this area later. There
isn't any mods needed to the FunJets design to add the FPV gear making
this build simple, just need to keep the CG in mind as you install the
wireless gear. I'm using a SN777 camera which
is smaller/lighter then most FPV cameras so I can keep the drag down to
a minimum. This camera also has great resolution. It will be mounted on
the canopy with a panning servo for 180 degree viewing. The wireless
system will be from ReadymadeRC.com's and
900 mhz 500mw TX also mounted to the canopy. For the OSD and GPS I will
be installing the Eagle Tree Systems eLogger, OSD pro and V4 GPS. For
the power system I have a E-flite 15 DF brushless inrunner with a
Castle Creations Thunderbird 54 ESC running off a 3S 3cell 2200mah 25c
lipo battery. This E-flite motor I can also run a 4S 4cell lipo for even
more speed. My hope is to keep this jet under 30oz ready to fly FPV. Another
thing that I have to consider is where to put the GPS antenna. The GPS
antennas do not like being close to video transmitters and if placed too
close it will not receive a good satillite signal. The FunJet has a
wingspan of 31.5 inches so I'm thinking that the GPS antenna should be
place somewhere out on the right wing putting it about 14" away from the
video TX. This should be plenty of distance to receive a proper signal.
Also with the added weight this is another reason I picked the right
wing as it well help counter the rotation of the motor
I added a carbon fiber flat rod to the wings which will help keep the wings from flapping with the added weight and speed.
Painted black on the underside so it can be seen easily by the spotter.
Black paint on the nose and under the camera to help prevent lens glare. Now
that the FunJet is done it's ready for a maiden flight the weight as it
sits is 28.4oz. This is with a 2200mah 25c 3s lipo, 60 amp ESC, E-flite
15 DF 3600kv BL inrunner, Eagle Tree OSD/GPS/logger, 900mhz vTX, SN777
Camera, AR7000 RX and 3s 500mah lipo for video gear.
calculations this FunJet should exceed 100 mph with current set up. The
Eagle Tree system will most likely be removed after a few flights have
been completed to gather data. This will be to save on weight if needed.
As of now the FunJet is under 30oz (25oz without OSD system) which is
the recommended weight to stay under if hand launching. Any heavier and
the FJ will be extremely hard to hand launch. Maiden flight
was un-eventfull as the FunJet was still hand launch-able. Tossed at a
45 decree angle it did dip a few feet until it picked up speed. Speed is
what this little jet is all about as it did well over 80mph at 3/4
throttle in level flight.