I've been flying my Long Range Twin Boom PVC plane for a couple of years now and it's
time to try something different even though it has more then proved itself as a durable plane.
I was looking at the Skywalker EPO plane which is highly recommended among FPV pilots and rightfully so as it's a good design for FPV flying. Both these designs look a lot like the "Raven" a small RC UAV that's used by the US military. I just don't care for foam for a long range plane so I choose to go with the fiberglass/balsa version from HobbyKing.com instead. The HK version is about the same price and it will need some mods like flaps. The clear canopy is cool but as most FPV pilots know it will cause glare on sunny days and distort the image....but I may have to at least try it :). This plane is large and a bit bigger then a Twin Star II and a little smaller then the HK EPP-FPV plane. The FPV 168 has a wingspan of 64"/168CM and 9" at widest wing area.
Planned Set Up:Motor: KMS 2826/06 730KV /50amp max/600 watts
Prop: Max is 10" with this low kv motor a 3 blade prop will be used.
ESC: 60 amp Turnigy
Servos: HS-65HB , HS-85MG nose gear.
FPV TX: 900mHz 800mw
Radio RX: AR9000/TM1000
Flight Batt: 4s 5800mah Lipo
Camera: WD600R or GoPro Hero Hd
OSD: Eagle Tree OSDpro/ GPS/ v4 eLogger
Co-Pilot: Eagle Tree RTH
CG: 3" (8cm) from leading edge
The plane is well packed and is complete with all needed hardware. I'm impress with it so far as the build looks good and no flaws. Here's the cons though.... The clear canopy isn't clear but slightly distorted and scratched but I wasn't planning on using it but maybe for mounting a camera on it...not in it. The other option is to make a nicer canopy from aluminum for better protection in case of a rough landing/crash. A problem I see now is the size of the prop can only be 10" which is small for a plane of this size so the 730kv 600watt (.40 nitro eq.) motor I had planned on using requires a bigger prop at 12-14. This plane using a 10" prop will need a higher RPM/KV like around 1400-1800kv /500-800 watts outrunner motor or a low KV/RPM motor like what I'm using with a 3 blade prop will have it be a sporty flier. I could always raise the motor an inch to fit a bigger prop but for now I'll try the 3 blade 10x7. For servos the plane is designed to use micro servos like the Turnigy 9g but the control surfaces are big and no way would I expect a weak micro servo to last very long so I'll be using Hitec HS-65HB on the ailerons, elevator and rudder along with a HS-65MG for steering the nose gear. The wheels that came with the kit are small....really small so I'm using taller 2-1/4" foam tires which will also help with rough dirt runways. The Build.
The plane came with no instructions but it looks straight forward. First thing was to locate the holes under the covering, then with a sharp blade get them exposed.
Cut the covering that is over the aileron servo tray. There's Gray covered balsa ply that fits here
that is provided in the hardware bag. The servos will be attach to the hatch.
Fishing the wires through to the front uses 4- 14" servo extensions or
2- 26" for the elevator and rudder connection.
The main wing is attached with 2 bolts and self gripping nuts on the inside.
The plastic cover acts for wind deflection over the motor mount along
with keeping the bolts in place when the wing is removed.
Comparing the size to a Easy Star.
Landing gear seemed weak but after gluing everything in
place it seems strong enough.
The plane needed a lot of front weight to get good CG so the batteries went to the nose
leaving lots of room for lighter gear in the center fuselage area.
The 6061 Easy Star aluminum canopy worked for the maiden flight and later
I'll be making a light weight aluminum canopy (below) for this plane that will be a heatsink
for the video transmitter also.
Maiden Flight Report:
I used the motor I had and went with a 3 bladed prop so I could get away with the 730 KV motor (.40 nitro eq) and push enough air....it worked Great :).
Set up as tested:
Weight RTF: 6lbs/2.70kg
Motor: KMS 2826/06 730kv/50amp max/18v max/600watts
Prop: 10x7 3 blade
batt: 4s 5200mah (2- 2s Turnigy hard case car lipo in series)
ESC: 60amp Turnigy 3-6s with 5amp BEC
Servos: HS-65HB/ HS-85MG Nose gear
FPV Gear: 900mhz 800mw/WD600r cam/ET OSDpro,10hz gps & v4 elogger/
Video batt: 3s 1000mah
To get the CG right I had everything in the nose. I used heavy hard case car lipos so I could get a good idea of the payload it can handle. The landing gear was plenty strong now that it's glued in and the wire held up but I did add a small bend 2" (40mm) up from the wheels that helped a lot. The wheels have a little positive camber when unloaded and sit perfect with weight. The front gear balsa ply is weak and needs to be glassed over or reinforced as on a smooth first landing it folded back...I thought at first it bent the wire but instead it came unglued. I used a ton of hot glue to do a quick fix out at the field that allowed me to get 2 more flights in.It does fly Nice and Smooth and I have for gotten how nice covered planes fly after flying foamies and helis for the past few years. The wing shape is some-what self leveling like a trainer but I personally like flat wings for performance but these where good and I did'nt have to fight it to stay in a banked turn much.Taking off used a lot of power and about 60'... pulling 32amps/470watts and OSD read 28mph as she lifted off. I'm not sure about how it would do being hand launch/belly landings with it. Flight speed is quick and I had it doing 69.2 mph in no time but once I settled in I kept it flying about 35-40 mph for cruise speed and later dropped it to 32-35 mph. At 26mph I could keep it level but altitude started dropping and a slight climb gave me the feeling of a stall about to happen so I landed it at 28mph with a cut throttle. It glided in nicely and at the last second gave a little flare....:Cruise it was pulling 10-15amps/140-210watts and at steep climb outs and take-offs 32-40 amps/500-600watts.Second flight I pushed it a little more. climbed to 300' and tested stall. At 23mph she stalled and dropped nose down so it was easy to recover...2nd stall 22mph and same. No tip/spin not bad for fully loaded with all the gear including heavy lipos.Third flight was uneventful and I just flew it far and high to get an idea of battery time with 5200mah 20 minutes and used 68%. The battery I will be using the most is lighter then what I flew with 4s 5800mha so I expect 30 minute flights in the future. to make up for the loss of weight I'll be using the GoPro so it will make it back up to keep the CG.:)
Next I will be adding Flaps to help slow it down for landing on shorter runways.
From the pilot cam WDR600.
Videos
New update: 02.07.2011
Custom Aluminum canopy is only 6 grams more then the stock plastic/balsa one but Much Stronger.
Allows for different servo placement and large opening for hooking up batteries without having to remove it.
Will handle heavier cameras like a GoPro HD without breaking on hard landings and added heatsink
for higher powered/hot running video transmitters.
I put some flaps on the 168 in a couple of hours.
It's a hollow wing area where the flaps are with 2 ribs. I glued in a
piece (approx. 1/4x1/4) balsa to the wing to close it off and for
attaching hinges. I notch the 2 ribs for the balsa to fit inside the
wing. I cut the wing with a fine tooth saw blade but a sharp hobby knife
would work also...just would be more work. The Flap stock that I used is aileron balsa from the local hobby store and I carefully peeled the Gray
covering from the cut off wing area and re-glued it to my new
flaps....Servos where easy and i just cut an opening for them to drop
inside.
More info coming soon!