Hi All!

I was reading one of the aviation pages relating to electric flight (full-scale) and found the announcement of the Nasa Green Flight Challenge and the amazing aircraft that won it! The Pipistrel Taurus G4...

Go ahead.. Look and drool... Just up our alley, right?

My plans are to build an R/C stand-off scale model of this plane in time for the Toledo show in about a month. I've been drawing, thinking and calculating and accumulating parts since before Thanksgiving. Now is the time to build!

I've got here an early systems diagram Here

More pictures to come.

Attached on RCGroups for good measure..

Here's my system sheet on the overall dimensions, target weight and power
calculations.

Current plan has a 4S Lipo (2 x 2S in series) to power this via the 14 x 10 prop.

More details on the planned construction soon.

cool subject! I was involded with one of the greenflite aircraft...cool stuff also...One of few pilots with all electric flite in the log book..

Here's the big picture plan.

I've not been able to find a scale model of the Pipistrel glider that is the basis for this composite aircraft, however, John Hoover - owner of Flightline Hobby up here in Lake Orion made a great suggestion.

Find a couple of Chinese ARF gliders of approximately the same configuration and use those as the basis of the project. The plane I found was the Discus CS 2.65 meter ARF glider from Flying-Dream.com.

Wingspan: 2.65m
Length: 1.15m
Weight: 1200g
Bubble Canopy and a T-Tail
High-Aspect Wings with tip-fins

A very close stand-off scale stand-in for the Pipistrel glider.

Through documentation online I figured out what I could do to recreate this aircraft and determined that a fabricated 30" center section with a motor pod up on top and the LIPO batteries in the wings would fit the bill. Most everything else stays stock.

To this end, I drafted up this plan and copied the base airfoil from the ARF.

Here's what I've come up with so far for equipment.

The servos (all 11 of them) are Hitec HS-81.
The ESC is a CC ICE-50.
The motor is a brushless 14.4V @ 600-800 Watts (45 A) .
The prop is an APC electric 14x10.
The radio is a Futaba FASST 7-channel
The servo hookups are a mixture of traditional plus new Futaba SBus

Here is about what the ribs are going to look like. The spar is connected to a steel rod passed throught the fuse pocketed in aluminum tubes.

The channels I'm using are:

Ailerons (1 from Rx, other via SBus - as are all RH fuse servoes)

SBus adapter is y-connection patched with only 1 cable going accross to the other fuselage and then distributed.

Rudders(2)
Elevator(2)
Throttle (1 connection direct)
Flap (center section direct)
Retracts(2)
Spoilers(2) Outboard wing panels via mechanical link.

My radio is a Futaba 7C 2.4 FASST for Mode 2.

Each fuselage servo network will have it's own battery (probably 2S A123) for both power reliability and ballast for CG adjustment.

My progress so far is to layout the ribs and mount the spar connect tubing.

The ARF kit is using a 1/4" steel rod going all the way through the fuse and socketing in both wings. There are smaller rods fore and aft in the ribs to align and anchor the wings on.

The center section will be full balsa-skinned and ultracote covered. I don't think I'll need to glass it, but we will see.

Next comes the motor deck and pod and then all of the ARF components.

One of the most challenging tasks for me will to be to carve a plug for and mold the motor pod cover.

Have been concentrating on control hookup on the ARF to have everything ready on the same schedule.

Have servos populated in the wings and tail, with 1 of 2 fuselages setup with control horns.

2 weeks to Toledo and I've been taking as much time as I can get away with to get this finished.

I've gotten the majority of the wing structure built up and have the lower surface sheeting mounted. Plans are to put in some diagonal bracing (suggested by club members at our "In the Bones" meeting.

I'm also planning on applying some carbon tape to the top edge of the spars and battery boxes to further reinforce the center section.

I've gotten a start on the motor mount which will also serve as the mounting point for the ESC. In addtion, if I need more cells I have room to put a 3rd pack in series inside the motor mount. I still need to figure out how to strongly mount the motor pod to the center section.

Last night the Skymasters Radio Control Club of Michigan had one of their last non-flying club meeting of the Winter which was our annual "In the Bones" meeting.

7 other members had wonderful projects to share with the Membership and guests.

I had the first opportunity to fully assemble the model (taped in place) with all of the flight surfaces mounted. The motor pod is taped in place at an approximate angle as I've seen in the full-scale planes angle with the landing gear down.

As seen, the canopies are resting in place so this is approximately how it will look with the exception of the motor pod cowl.

Some of the suggestions from experienced builders included adding diagonal bracing between ribs, surface carbon fiber tape and tying in the battery bays more tightly to the wing joiner tubes.

Another concern raised was about the possiblity of the two tail sections moving in different directions since they are not currently connected in any way. The concern is that this would put twisting stresses on the center section and contribute to instability.

The suggestion was to run some sort of joining rod or tube at the rear of the fuselages to maintain separation distance and couple the movement of the tails.

We've got a family road trip planned over the next week, so no further progress will happen until the week before Toledo. It's going to be quite the manic week!