Design and Building

Check back here again shortly since I will be adding more info.  If there is any interest I will also post the drawings / plans online as well.

General

My general design criteria was to make a lightweight fun-scale fuselage that was easy to make, durable, and in no way interfered with normal flight operations.  That means no impossible to reach needle valves, difficult fuel tank filling or a zillion screws to get off.  I also wanted to push the envelope a bit with some 'live' rocket firing just for fun.

The fuselage is made of 1/16" balsa sheet reinforced with Kevlar and Carbon fiber.  It is in two pieces.  Initially I was just going to make the front part and leave the aft boom area stock.  As I progressed on the forward fuselage I became more aware of the bareness of the rear of the chopper with just that boom and boom supports to look at.  I made a couple of cardboard templates and wound up deciding to go ahead with a rear fuselage.  I am very happy I did.  

The front fuselage attaches exactly like the original and can be popped off quickly.  

The balsa was sealed with Balsarite and covered with Micafilm.  I then painted it with an airbrush using water-based acrylic paints sealed with clear polyurethane.  I had originally bought a can of "Satin" polyurethane but it turned out too shiny.  I mentioned it on RCOnline in the Tips and Technique forum and someone suggested talcum powder as a flattening agent.  It worked perfectly. 

Landing Gear

I made a wheeled gear support out of carbon fiber.  It ties the front and rear of the fuselage together (which might be desirable even on the skid version) and supports 5/32" piano wire gear legs.  It attaches at the same 4 screw holes as the original. The rear wheel is mounted on a carbon fiber support of the fin assembly.  I've got some detailed pictures of the gear somewhere and I will put them here when I find them.

Weight

The entire structure including gear, forward and rear fuselages, fins and rocket pods weighs less then the original Raptor parts they replace! The heavy (8oz) polypropylene Raptor canopy along with the plastic fins, aluminum boom supports and fiberglass/aluminum gear are together in excess of 1lb!  

Forward Fuselage

As you can see by the pictures it is a slab-sided structure of simple 1/16" balsa.  It has some internal bracing and Kevlar in high wear / structural / bending areas. I used bamboo sticks to reinforce the window / glass structure.  I built the electrical wiring into the pods for the missiles out of thin strips of copper.  The copper strips glued into the pod wings add some extra rigidity and carry current to the pods with virtually no loss.  The cockpit floor is a computer generated floor and instrument panel printed on Kodak photo paper and cut to fit on small balsa reinforcements.  Other graphics were printed on clear plastic and attached later..

Rear Fuselage

The rear fuselage is also made up of 1/16" sheet but has carbon fiber 'booms' running along the bottom.  This structure is cross-braced by a bottom piece that makes an incredibly stiff structure.  The rear fuselage attaches to the boom at approximately the same point as the stock booms do but with a nylon tie-rap over double side tape to get a very strong (but removable) bond.  The front of the rear-fuselage attaches at the top at the canopy attach screws and at the bottom at the normal boom supports.

In the following photo shown with the Raptor standing on it's nose with the front fuselage off, you can see a little of the attachment and the antenna running down the inside.  The front of the rear fuselage is open to allow the fuel tank to be seen clearly while flying.

Tail

The tail is 1/16" balsa as a sandwich between carbon fiber cloth.  The tailwheel support is also carbon fiber.