This winter I have decided to experiment with slightly larger electric aircraft. The proven 27% Extra seemed like an ideal place to start. This decision was taken to meet the increasing need to quieten our larger aircraft and be proactive in keeping noise to a minimum at flying fields.
Hangar 9 Description;
Legal for both Giant-Scale and IMAC
Superior precision and 3D performance
Flies with a wide variety of engines, including lightweight 50cc gassers
Designed by world-class competitor Mike McConville
Lightweight balsa and plywood construction
Carbon-fiber main landing gear and tail wheel
Covered in genuine Hangar 9® UltraCote®
2-piece high wing and stabilizer
Able to fly smoothly with a wide variety of engines, including the lightweight 50cc gassers and Saito’s
FA-180 and FA-220 4-strokes, the Extra 260 is capable of superior precision and 3D action. It’s constructed from very lightweight balsa and plywood, guaranteeing higher performance and more fun. The attractive landing gear is constructed from durable carbon fiber, which is much lighter than aluminum, yet still provides plenty of strength for rough landings.
Designed by aerobatic ace Mike McConville for high-adrenaline fun, the Extra also offers sturdy-but-lightweight all-wood construction, carbon-fiber main landing gear and tail wheel, and a beautiful UltraCote® scheme—ingredients for a high-performance airplane certain to excite giant-scale pilots everywhere.
Wingspan: 78 in (1981mm)
Overall Length: 72.25 in (1835mm)
Wing Area: 1134 sq in (73.2 sq dm)
Flying Weight: 11.5–15.5 lb (5.2–7.0 kg)
Engine Size: 1.20–2.20 2-stroke; 1.40–2.20 4-stroke; lightweight 50cc gas
Servos: 6 servos minimum
Trim Scheme Colors: White (HANU870), True Red (HANU866), Pearl Blue (HANU845)
Hardware Included: Yes
One thing you might notice from the above spec’s is that this extra was primarly designed around glow engines and DA’s 50cc petrol. I decided to fit an Eflite Power 160 motor to this airplane, with this motor a 85amp esc and 10s 5000mah battery setup (2x Eflite 30c 5s 5000mah lipo’s) gives performance similar to a 160 sized glow motor.
To install an electric motor rather than the Glow/Gas engine was a simple enough process. As shown below a standoff box was required to extent the motor from the main fire wall. The rest of the build was straight forward and exactly as you would expect from Hangar 9. I elected to use Spektrum A6030 servos on a controls, 20kg of torque is way overkill but I like these servos, precise and reliable. I used Spektrum’s new 10ch RX the AR10000 and a simple 6.6v Life Rx battery 1300mah from Dynamite, which i will charge every 2-3 flights. One 5min flight used 170mah from the pack so it’s well safe. I went this way to keep weight to a minimum.
Test Flight Pictures
Ready to go. We haven’t finally fitted the spinner just yet, I want to experiment with props before I finally cut/fit the spinner. At the moment I’m using a Wooden Master Airscrew 20×10 Scimitar prop, so far I’m impressed. Good speed & thrust, very quiet in the air with no ripping and the it’s only drawing about 70amp’s at full power.
This a really nice sized aircraft, and the extra 260 is still one of my favourite designs.
Low pass on a windy testflight. It was well above 20mph and was bitterly cold.
High Alpha KE, CofG feels about right in the air and KE mixing is minimal.
I didn’t want to push it on the test flight, I limited it to 3mins.
I had two test flights on the day, the first one was very sedate, 3mins of gentle aerobatics. I put about 1700mah into both packs after the first flight. All the components were cool after the first flight. I had the telemetry working and the temperature sensor hooked up to the ESC showed a maximum temperature of 21-deg, the outside temperature was around 4-deg. The second flight was on another set of batteries and this time I pushed it a little harder, flight was 4 1/2mins of harder aerobatics, longer uplines and a little 3D. In the 20mph wind the plane handled really smoothly and the power was ample in the conditions. Temperatures were about the same as the first flight, flight pack voltage showed a minimum of 32v, which is fine, Capacity wise, I put about 2250mah into both packs after this flight, so still well within the 5000mah for each pack, realistically I wouldn’t want to exceed 4000mah per pack at the most, that’ll keep them better for longer.
Some Photo’s of the Power 160 motor install are below.
Motor within the cowl
The standoff box, we also cut some lightening holes into the existing engine box and bulkheads, to save some weight. Remember this was designed to take the load/vibration of a DA50, with this motor no vibration we will have much less torizonal load.
Another view of the lightening holes. Not the ESC mounted under the standoff box. This means air is directed onto it from a whole cut under the cowl.
The ESC RPM sensor, gives you realtime motor RPM. One neat feature is that if you using this on a helicoptor, you can identify your gear ratio and this will tell you your Head speed.
The temperature sensor on the side of the ESC, helpful to have.
The telemetry wiring, looks a little complicated, but its not, very simple when you lay it all out,
Main Flight packs telemetry pickup, display the flight pack voltage on the Tx or your Iphone via the new Spektrum STI module/app.
We made up a battery tray to make the fitting of the flight packs simple.
A Y lead to link the 2x 5s5000mah in series to give a 10s1p5000mah pack. We have used EC5 plugs, they are good for well over 120amp per connector on 10awg wire.
The battery tray sits on top of what was the tank tray. In the picture above it shows the angle you need to slide the tray in at. Two guide rails at the head of the battery, prevent the tray from moving up or down and side to side.
At the rear of the tray, a simple nylon screw holds the tray down and stop it from moving in any direction. To me this is a simple way to hold the batteries in place, velcro can be difficult to secure inside fuselages and can sometimes lead to accidental damage.
I’ll update you on how the Extra is going as I build up more knowledge and experience. From my two flights all things are positive and I think this could prove a popular and affordable solution to noise reduction.
Also look out for something a little bigger on the electric front in the coming months.