by: Frederick Boucher [ ]
Originally published on:
North American XB-70A-1 Valkyrie
AMT/ERTL filled a void in large Cold War aircraft with 1/72 B-52s, KC-135s, and then USAF flying wing prototypes. They didn't stop and kitted the amazing XB-70 Valkyrie. The XB-70 is an sight to behold in real life or as a model.
North American XB-70AThe XB-70, one of the world's most exotic airplanes, was conceived for the Strategic Air Command in the 1950s as a high-altitude bomber that could fly three times the speed of sound (Mach 3). Because of fund limitations, only two were built, not as bombers, but as research aircraft for the advanced study of aerodynamics, propulsion, and other subjects related to large supersonic aircraft. The Valkyrie was built largely of stainless-steel honeycomb sandwich panels and titanium. It was designed to make use of a phenomenon called "compression lift," achieved when the shock wave generated by the airplane flying at supersonic speeds supports part of the airplane's weight. For improved stability at supersonic speeds, the Valkyrie could droop its wingtips as much as 65 degrees.
The initial XB-70A (S/N 62-1) was rolled out on May 11, 1964 and made its first flight on Sept. 21, 1964. It flew a total of 83 times when, on Feb. 4, 1969, it made its final flight to Wright-Patterson Air Force Base, Ohio, for delivery to the National Museum of the United States Air Force where it remains on public display in the Research & Development/Flight Test Gallery.
The aircraft flew supersonic (Mach 1.1) for the first time on its third flight, Oct. 12, 1964. On March 24, 1965, the aircraft surpassed Mach 2 for the first time during its 15th flight. Mach 3 was achieved for the first time on Oct. 14, 1965, during the 17th test flight.
On April 25, 1967, XB-70A-1 made its initial flight as a NASA test aircraft. Of the 83 flights of this aircraft, the USAF flew the first 60 and NASA conducted the last 23.
The No. 2 airplane (S/N 62-207) first flew on July 17, 1965, but on June 8, 1966, it crashed following a mid-air collision.
The delta wing of the XB-70 has a span of 52 feet 6 inches and is swept back 65.5 degrees. The outboard sections of the wings (20 feet) were capable of being drooped (lowered) in flight to increase high speed flight performance. The maximum drooped position was 65 degrees down angle and was used during supersonic flight. A transitional position of 25 degrees down angle was used as the XB-70 accelerated into supersonic flight. The variable geometry wingtips acted as vertical stabilizers when in one of the two drooped positions; however, their primary function was in the compression lift system. The lower fuselage was designed in a "Vee," or wedge shape, specifically to slow the airflow around the lower fuselage by creating an air dam. At speeds around 2,000 mph (Mach 3), this "air dam" slowed the air stream to about 1,600 mph, creating the compression lift -- the aircraft essentially rode on top of the compressed air dam thus creating the lift. At 2,000 mph, with the wingtips drooped to the full down position, compression lift carried approximately 35 of the aircraft's weight. The drooped wingtips acted to confine the airflow and increased to efficiency of the compression lift phenomenon. With the wingtips in the full up position (0-degree droop) compression lift was lessened by about 10 percent.
The XB-70 was equipped with two fully moveable vertical stabilizers, 12 elevons -- six on each wing trailing edge (an elevon is a combination elevator and aileron for pitch and roll control) -- and a canard surface mounted just behind the cockpit on the forward fuselage. The reason for having 12 small elevons rather than just two was to allow for greater control of the aircraft over the entire flight speed range. At landing speeds of less than 200 mph all twelve elevons were needed. At 2,000 mph with the wingtips drooped, the three outboard elevons on each wing were locked to prevent over stressing the airframe if sudden violent control inputs were required. The canard surface was all flying but also had trailing edge flaps. The canard's primary purpose was to balance pitch forces (up and down movements) normally controlled by the horizontal stabilizer and elevator on a conventional airplane.
The two XB-70As completed were never intended to be anything other than very high speed test aircraft. Because of advances in enemy air defenses during the late 1950s and early 1960s in both interceptor and surface-to-air missile design, the high-speed, high-altitude penetration bomber mission was seen as too risky and left the aircraft and crew very vulnerable to attack. Bombers capable of low level penetration or standoff weapons delivery were judged more practical. The growing value of the Intercontinental Ballistic Missile for strategic deterrence also had a negative effect on the XB-70 and similar programs (e.g. XF-108). 
What's Inside the big boxA big model! Built it is almost 3 feet long. Packed in a big top-bottom box; the lid is flimsy cardstock while the bottom is very sturdy cardboard. Inside are decals, two sheets of information and instructions, over 73 parts on several sprues of off-white styrene, and two clear canopies. I acquired the model second-hand and several parts were not attached to a sprue; perhaps the wings and lower center fuselage were not packed on sprues?
The molding quality is generally high. Some parts have mold seam lines slight flash, ejector marks, yet no sink holes. Those mold seam lines are noticeable and, unfortunately, ruin the landing gear torque arms. The ejector marks I spotted mainly are on interior surfaces, but they also mar the visible inside of the landing gear doors. Happily the external parts are molded clean. Unfortunately, some of the detail is soft -- rounded edges and corners, e.g., the afterburner nozzles. The model is detailed with fine recessed panel lines, although there are a few raised lines. Several louvers and vents are molded open and the plastic is thick. As is the tree branch-like nose pitot tube. You may want to address the thick trailing edges with sandpaper.
Two clear parts allow you to model the Valkyrie nose up or nose down. They are clear with raised framing.
The wingtips can also be positioned down for high-speed flight.
I fit a few airframe parts together and it seems that while this model won't just fall together like a Tamiya, it shouldn't tax the ability of intermediate modelers.
DetailA good cockpit is provided even though it probably isn't very visible. Bezels and dials and switches are molded raised. Two ejection capsules are also provided as are two control yokes.
Gear well detail is molded but the wells are very shallow. The landing gear is fairly well done. I think AMT/Ertl compromised between detail and weight bearing ability. The prototype landing gear are beefy and so are the model's; they are large enough to detail with the ganglions of wire and piping I saw on them.
The burner cans have a great deal of exterior and interior detail that AMT/Ertl neglected to mold.
Decals, Instructions, and paintingYou have a simple livery -- USAF research overall white. Only a black anti-glare panel and insignia sullies the snowy finish of this jet. Some painting suggestions don't seem right for what I saw on the aircraft last summer.
Decals for only one aircraft, S/N 20001 -- the survivor -- are provided. It also has the NASA markings for the Dryden Flight Research Center days. There are some stenciling and warning lines. While nicely registered and printed the decals seem to be thick. Lots of carrier film that needs a very high level of skill to set on a white airframe without showing.
What appear to be a pair of instructions are actually the big, folded instruction sheet, and a sheet similar to blue prints. One describes how to build the model and the other relates, in good detail, the history of this big bird. It also has a section of tips 'for advanced modelers.' According to the text AMT/Ertl was allowed access onto and into the aircraft for measurements and detail shots.
ConclusionThe XB-70 is an awesome aircraft. I thoroughly enjoyed seeing it last summer at the National Museum of the USAF, images of which are here at Aeroscale in photo features. Big as it is it was difficult to photograph. All the same it may make your pulse quicken a bit when you see it. Just like this model. AMT/Ertl did a fine job with the model.
Molding is good if thick. Perhaps behind the times for 1995, the year the model was kitted. Fit seems to be good.
Detail is adequate on the airframe and in the cockpit and on the beefy landing gear.
Limited detail on the afterburner nozzles is disappointing, as is the soft detail elsewhere, and all the seam lines.
Overall I think this will build up into a pleasing model.
AMT/ERTLAluminum Model Toys, or AMT for short, was a Troy, Michigan based company that manufactured various pre-assembled plastic promotional models starting in 1948, when attorney West Gallogly, Sr. started it as a side business. Later, a variety of kits became very popular. Most of the company's vehicle products were American cars and trucks in 1:25 scale. In the 1970s, hot rods, customs, and movie and TV vehicles were also produced. In 1978, British Lesney, makers of Matchbox bought AMT and moved the company to Baltimore, closing the Maple Road facility in Troy, Michigan (just outside Detroit). (Cawthon 2002). By this time, prices of plastics had increased, and Detroit was squeezed by government regulations of safety, emissions, and fuel economy. Detroit sponsored fewer and fewer promotionals, and model companies depended more on kits – but the building hobby declined as well. Also, AMT had an incredible display of models and documentary history at its headquarters that was scattered at that time (Anderson 2003). In 1983, AMT was purchased by Ertl from Lesney, and renamed AMT/Ertl. AMT/Ertl then had a 24 year relationship until AMT was sold in 2007. For a time, AMT kits were reissued by independent companies such as Stevens International and Model King, before AMT came solidly into the stable of Round 2 LLC of South Bend, Indiana. 
The Ertl Company is an American toy company best known for its die-cast metal alloy collectible replicas (or scale models) of farm equipment and vehicles. Ertl has been producing farm toy replicas since 1945. Ertl is currently a brand under the RC2 Corporation umbrella. 
AMT/Ertl Today?Italeri owns the tooling. They cost about $70.
. Wikipedia. Aluminum Model Toys. [Web.] 30 December 2012 at 17:52.
. Wikipedia. Ertl Company. [Web.] 12 December 2012 at 15:51.
. National Museum of the USAF. Fact Sheets North American XB-70A. [Web.] 7/8/2009.