Douglas F-4D Skyray 1/5 scale

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  • Regular price $4,495.00


Introduction.

This is the new large Hyper scale Frankel Skyray.

This plane is the ultimate realization of the World Skyray specialist. Our friend Mark Frankel.

Mark has worked all his life to gather documentation and blue prints of this plane. he has written many books about it and know it inside-out to the smallest screw.

Here is what he says about the plane in his book " Killer Rays ":

"The Skyray generated a lot of emotion. It was an elegant solution to a defense requirement that was, at the time, impossible to accomplish. It was meant to climb like a bat out of hell and fly faster than anything else in the air. It accomplished both."

 

The Skyray held the World speed record for several months and had a typical climb angle of 70 degrees at 28,000 fpm.

The large Frankel Skyray was CAD designed by Guido Ising and modified to suit our manufacturing techniques. It features 11 different types of rivets and fasteners spread over 35,000 times on the airframe. The skin panels are worked to reproduce the wrinkles generated by their riveting on the internal structure. 

 

Technology:

The plane is available in 2 building options:

KevTech and Cloudtech.

Kevtech is made from ultra thin kevlar fiber/ 1.5 mm  ultra light aerospace grade core material.

Cloudtech is made from high modulus carbon fiber uni-directional non crimp fabrics and a thin 1.5 mm ultra-light aerospace grade core.

The core material is a specific ultra light weight aerospace grade PEI foam that is certified to sustain 120 c continuous without de-gassing. This foam is 3 times lighter than the Airex grade used on the best models being currently sold to the hobby market and features the much higher resistance to compression.The skin created using these materials is infused in one step with a very specific resin gel sheet technique. A super high modulus epoxy resin is used and post cured for 48 hours at high temperature, offering a resistance of 120 c continuous.

Architecture:

The plane internal structure was designed and specced using finite analysis simulation to offer 10 g resistance with up to 220 N total thrust. The internal structure is CNC cut and 100% made of Airex/ carbon fiber laminate with the same epoxy gel sheet  resin as the skin and post cured in one step with the remaining of the structure. The wing and fin tubes are also aero grade carbon fiber made and post cured in the same step with the structure to fuse the glue joints with the spar/ ribs. This is a unique process allowing both the skin and the internal structure to cure together and fuse with the epoxy joints, creating a virtually monocoque shell

The landing gear struts were CAD designed by Guido Ising and adapted to our hybrid CNC/ laser 3D printing technology.

 

1/5 scale Skyray main gear introduction. from Oli Ni on Vimeo.

 

 

The strut covers are 3D printed to 25 micron accuracy, thus retaining the highest scale appearance, while being user replaceable in case of damage. The internal strut is CNC machined on our Siemens machines from Alcoa Al 2024 T351 and Al 7075 T651. The retracts and billet machined from an aluminum-titanium alloy made by Alcoa at their Lafayette plant. They use powerful 20 mm motor with planetary gear reduction and step counting output.

The nose gear has direct servo steering. 

Powerplant:

The plane is designed to be powered by engines ranging from 160 N to 250 N.

The engine placement is located on the CG to reduce plane inertia. The integral bypass system is fa ull high temperature pregreg carbon fiber, post cured at 200 c. The bypass system is very efficient and runs completely cold. The rear thrust tube is hard mounted to the engine/ center fuselage section and is made of austenistic alloy/ high temp carbon fiber.

The fuel system offer 3 types of configurations.

1. 6 liter configuration with 2 kevlar tanks.

2. Ultra light 5 liter single bladder tank.

 

Version:

The plane is available in 2 versions;

.Kevtech JWM. This version is designed to flyy on a Merlin 166TS engines to stay within the JWM 20 kg limit.

.Cloudtech, full carbon fibre.   This version is designed to fly with a Frank Turbine FT250 engine.

 

Flight controls:

The F-4D Skyray has got very specific flight control setup.

It has a set of 4 controls at the back of the delta wing which are connected together to keep them immune to vortex induced flutter. The outer side includes a counter tab.

It also has a set of large pitch trimmers and slats which are designed to work together. When the gear is extended, the slat extend and trimmer moves up in a time frame of 6 seconds. This sets the aircraft at the proper nose up attitude for approach.

The fin has a split rudder. The upper portion is used for yaw damping and must be connected to the gyro if in use, whereas the lower portion is the rudder.

A total of 10 servos are required for the flight controls, plus 1 for steering and 5 for the gear doors.

 

 

 

Specifications:

Length: 276 cm/ 109"

Span: 204 cm/ 80"

Dry weight: 19 kgs-24 kgs/ 41-53 lbs

Takeoff weight: 23 kgs-29 kgs/ 50-64 lbs

Engine: 160-250 N