Convair NX-2 (oz16954)

About this Plan

Convair NX-2. Free flight scale model for rubber power. Pusher pop layout.

This model was inspired by the Quickie Canard Glider (oz16902) that mentioned the Convair NX-2 as the inspiration for the glider. I enjoyed the research of the early atomic powered aircraft proposals. Following WWII many things were experimented with. I believe the only nuclear reactor ever place in an aircraft was the B-36H but not for power of the aircraft. Kinda scary stuff in the 50’s.

CONVAIR NX-2 CAMAL

The history of Convair NX-2 Camal, a secret project to develop an atomic-powered bomber.Convair’s NX-2 (designated Model 54 in-house) proposed powering the subsonic, ultra-long endurance jet bomber (about the size of a B-52) with either Pratt & Whitney indirect air cycle nuclear engines or General Electric direct air cycle nuclear engines. The U.S. Nuclear Propulsion Program (or Manned Nuclear Aircraft Program) began in May 1946. This after Fairchild Engine and Aircraft Corporation, received the first formal study contract. The objective, is to determine the feasibility of nuclear energy for the propulsion of aircraft.

The Fairchild project known as the Nuclear Energy for Propulsion of Aircraft (NEPA) began at the Oak Ridge National Laboratory, TN.Work at Oak Ridge proved building a nuclear aircraft was feasible and defined the major approaches to the program. As a result, the Air Force and Atomic Energy Commission (AEC) joined forces in the Aircraft Nuclear Propulsion (ANP) Program. In 1951, they contracted with the General Electric (GE) Company at Evendale, Ohio to, “…develop a nuclear aircraft propulsion system through an exacting research, development, design and component-test program on reactors, materials, shielding and an overall nuclear power plant.” 1

At the time, there appeared to be two design concepts for a “nuclear” aircraft: the Direct-Air-Cycle and the Indirect. General Electric elected the Direct-Air-Cycle2 due to the perceived simplicity, flexibility, adaptability, and ease of handling. General Electric quickly developed high-temperature, compact, lightweight reactors and shields required for aircraft flight. The GE Company also believed their new technology had applicability to aerospace and ground power systems. In the 1950s, nuclear reactors were approximately the size of two railroad cabooses stacked on one another, and the performance requirements for aircraft nuclear power plants were much moreschematic.The objective of the ANP Program expanded to include the demonstration of nuclear-powered flight. Still, in 1952, the Air Force decided that direct nuclear cycle engine developments were progressing well and began construction of a power plant for the Convair B-36 flight testing and targeted 1956 for the first flight.

In 1953 the Secretary of Defense Charles E. Wilson abruptly canceled the B-36 experimental flight program, Wilson, a skeptic, contended “that experimental “proof-of-principle” flights were worthless unless they were performed by a prototype for as an actual weapon systems.”4 The money slated for the project was for a weapons system so, the prototype requirements leaned in this direction.Though the B-36 experiment halted, Air Force leaders managed to keep GE’s direct cycle developments moving forward and Pratt and Whitney continued their progress. Pratt and Whitney used a pressurized water, indirect cycle engine which failed to progress (see below schematic). Pratt and Whitney changed gears and began working with Oak Ridge on a molten salt circulation fuel reactor, still using the indirect cycle nuclear turbojet concept. Pratt and Whitney remained behind GE in developments throughout the testing and experimentation.

Though Air Force leaders canceled developments for a B-36 nuclear-powered aircraft, a Convair B-36, designated as the NB5-36H and specially refitted to contain a fully operational nuclear reactor however, the NB-36H did not use the reactor for propulsion.In 1958, the Air Force introduced a new mission requirement in an attempt to keep the ANP Program alive. Known as CAMAL (continuous airborne alert, missile launching, and low-level penetration), it was a rehashing of a nuclear weapons system aircraft.8 During the summer of 1959, Dr. Herbert F. York, Director of Defense Research and Engineering in the Pentagon, and other Department of Defense research officials pushed a reorientation of the ANP Program project. These officials called for the development of a useful nuclear turbojet capable of installation in and flown on a Convair Model 54 (the NX-2).

CONSTRUCTION:

FUSELAGE: The fuselage is made in three sections, central body and starboard and port engine nacelles. This will be a challenge yet it will allow the various shapes of the fuselage to be achieved without large formers. The center and outer nacelles are built in box style constructions. It will be noted the formers for the top of the fuselage and the rear of the nacelles. The exhaust nozzels are constructed by hollowing out balsa blocks. Keep them as light as possible. This model can be built as a pusher or traditional tractor rubber powered scale model.

WING: The wing is made using the cracked rib method. Layout the ¼” on edge leading edge and the 1/16”x1/2” trailing edge on the plans, (be sure to cover the plans with a protective paper/kitchen wrap to keep the glue from sticking to the plan), now lay down the 1/16” SQ bottom of the ribs. Once the bottom of the ribs have been glued in place to the L.E. and T.E. add the 1/16”x7/8” tapering to 3/32” at the tip over the bottom of the ribs as shown on the plans. Once this has dried it’s time to add the 1/16”sq upper cracked ribs in place. Glue to the L.E. and then bend gently over the spar cracking this rib down to the T.E. and trim at the back of the T.E. and glue in place. A drop of thinned Duco glue at the crack over the spar adds strength and attaches it to the spar. Once all the upper ribs are in place a 3/32”x1/8” turbulator strip added between the spar and L.E. will help to round out the airfoil of the cracked rib wing.

CANARD: The canard is made of 1/8” sheet balsa sanded to an airfoil shape. I use a small diameter music wire in an “L” shape that is attached to the rood of the canard. This wire will stick out ½” and can be taped to the fuselage to hold it’s incidence setting. The canard uses an 1/8” dowel through the fuselage as a mount and adjustable hinge for the incidence.

FINS: The vertical stab/fins are made from sheet 3/32” and sanded to and airfoil shape. These are attached to the wing tips in a vertical angle.

Hope this is a challenging and fun model that you won’t see many other modelers bringing to the field.
Regards,
Tom Akery/Sky9pilot"

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