Tuesday, August 31, 2010

The Wing

Micro servo mounted in one wing.  Control horn and rod installed.  Cover pulled aside for now.


With servo cover installed.  Wing section ready for joining with other sections.
Before joining, the ends were cleaned free from covering to ensure a good bond.
Aluminum wing struts are inserted into the wing end section.  Servo wires are threaded through the wing, soldered and shrink wrapped to the servo extension wires in the center wing section.  CA was applied to the exposed wing rib and the sections pressed together. 
The result of two wing ends and center section joined together.  72" wing span ready for motor and landing gear.  Next step - prep for finish work.  I need to fill in the crack between sections with a light weight spackle and get the wing ready for covering with aluminum tape.

Thursday, August 26, 2010

The Setup

The parts laid out, gonna toss those brushed motors and 8x4 props to the side

After fussing with a number of power setups using Drive Calculator Software, i finally selected a power plant.  I place my order from HobbyKing today.  Here is what is on the way:
 This setup should give me about 3200g thrust, drawing 700W at full throttle.  Pitch velocity was estimated at 64mph.  This should be way more than i need, so i'll probably be flying at less than half throttle most of the time, but it is capable of getting me out of trouble if i run into it.  I probably should have gone with 60amp ESC's, as at WOT this setup should draws 36 amps on each.  I have a watt meter, so i'll do some testing when i get the parts in.  This will be my first twin, first 3-blade prop setup, first bird over 3lbs and 50" ws.

The Vision

To date I haven't really had any true builds.  A trainer ARF that took about 4 hours, a sport ARF that took about 8 hours, and an foamy EDF jet that took about 2 hours.  I was looking for a challenge and decided I wanted to try a scale ARF plane with some mods.  I like the old planes that used to fly in Hawaii, and started looking at what Hawaiian Airlines used to fly.  The fourth aircraft introduced to the HA fleet, and the first true passenger plane, was the Douglas DC-3 in 1941.  Over the years, HA operated 13 of these birds until they were retired in 1966.  They represented the classic years of a new airline in the territory of Hawaii.

Flying over Haleiwa in the 1950's
Parked on the tarmac at HNL, 1956

I found an interesting DC-3 ARF kit on ebay, manufactured by Protech (re branded from Polk).  The model features a built-up wing, stabilizer and tail, and a blow-moulded fuselage.  She's got a 72" wingspan, and is 48" long.  It comes with two 600speed brushed motors, which I heard are way underpowered for the plane.  Finished flying weight comes in around 6-6.5 pounds depending on the batteries.  They look a little bit cartoony built right out of the box.

Someone else's stock Polk DC-3 Build


My planned mods are as follows:
  • Brushless Conversion with Lipo power and 3-blade props
  • Modified landing gear (stock gear is too stiff)
  • Vented nacelles
  • Steerable tail-wheel
  • Enlarged batter compartment with access door
  • Receiver switch
  • Early HA paint scheme