NATC Test Course Descriptions

Gravel

The Churchill Course is a local gravel road located on a lower terrace. It is level to undulating with slopes up to 3 percent. The surface contains some washboard effect with varying degrees of depth and spacing. The alignment is mild, containing only a few curves requiring a decrease in speed to negotiate them safely.

Perryman A

This course is located on bottomland flat and lower terrace terrain with slopes up to 3 percent. The course is a 3 mile gravel and clay road consisting of man-formed and natural terrain. The surface roughness is moderate, with limited washboard, potholes, water erosion, and rock outcrop features. Periodically this road is graded. The course alignment is mild, although it contains several sharp curves.

Perryman I

Perryman I is an old railroad bed located on a level, lower terrace and bottomland flat. The bed was constructed from in-situ materials consisting of fine-grained soils with some rock. The course is rough due to old ruts and potholes. Portions of the course are flooded when required for testing purposes. The alignment is reasonably straight, but does contain some mild curves.

Perryman II

This course is located in a bottomland flat with slopes up to about 3 percent. The in-situ material is a mixture of fine and coarse-grained soils with some gravel. The surface is moderately rough with ruts and potholes 0.5 to 5 inches in depth. The course alignment consists of straight and mild curve sections.

Perryman III

This course is located on a bottomland flat and a lower, level terrace. The soil is indigenous and it is made up of fine-grained material. The surface profile is similar to Perryman IV except that the amplitude of undulation is less severe.

Perryman IV

Perryman IV is located in a bottomland meadow. The course was constructed of in-situ fine-grained soil materials which simulate marshland. Random man-made conditions with varying frequency and amplitude magnitudes has produced an irregular surface. Vehicle break-over angles are critical to negotiating this course.

Churchville B

This course is located on an upland slope and plateau. It is hilly with slopes up to 30 percent along the course. The material is natural, consisting primarily of boulders mixed with gravel, sands and some fine sands. The surface roughness is moderate to severe. The alignment of the hilly portion of the course is a combination of switch backs, and on the upland plateau, the course is moderately to severely undulating.

Belgian Block

This course is 1,970 feet in length. The course was built based on DFMV measured profiles of the Aberdeen Test Center Belgian Block course. It is made up of naturally undulating terrain covered with basaltic rock. Additional “Belgian Block” courses used to simulate the various cobblestone roads found around the world are also available. The concrete block course provides a random combination of pitch and roll, as well as high frequency, low amplitude vibration. The course is exactly one-half the length of the standard APG Belgian Block course. The course provides high energy inputs to wheeled vehicles and is utilized in certification to MIL-STD-810.

2" Washboard

This course is formed by a mixture of clay and cementable materials. The course is 411 feet long (one-half the length of the APG 2" washboard course) with an amplitude of 2 inches and a 2 foot peak-to-peak spacing. The course form is sinusoidal and is utilized to evaluate wheeled vehicle suspensions. This course is certified to the requirements of MIL-STD-810.

Radial Washboard

The radial washboard course is 243 feet long and is formed from clay and cementable materials in a packed clay base. This course is sinusoidal with a varying amplitude from 2 inches to 4 inches and a wavelength of 2 feet to 5 feet. This course is the same length as the APG radial washboard course and is certified to the requirements of MIL-STD-810.

6" Washboard

This course is 798 feet long. It is a continuous sinusoidal wave form with an amplitude of 6 inches and a wavelength of 6 feet. The course is constructed of a mixture of clay and cementable materials. The course is certified to the requirements of MIL-STD-810.

3" Spaced Bump

This course is 764 feet long and is constructed of spaced timbers set in a concrete base. The timbers are angled and rounded to provide a 3 inch high obstacle. These bumps are irregularly spaced and are angled to the vehicle path to provide random shocks to the vehicle system. The obstacles are spaced to allow the vehicle suspension to "settle down" between impacts. This course is certified to the requirements of MIL-STD-810.

Standard Slag Road

This paved test area is 11.0 miles in length; 4.5 miles of the course is straight and level. The remainder of the course contains curves and slight grades. This asphalt road was built for axle loads to 80 tons and gross vehicle weights to 160 tons. This road is utilized for high speed, dynamometer, braking, cooling, and handling tests.

Fort Churchill Road - West End

This course is 10.6 miles of graded gravel surface. Fill material includes both barrow pit and 3/4" minus processed river gravel. The sub-surface is compacted clay and sand. This area has straight and level sections for 2 miles with intermittent left and right curves. The road width is 30 to 40 feet.

Hooten Wells Road

This test area is 11.1 miles of maintained sand and gravel road on a natural base with intermittent curves and straight level sections. Road width is 25 to 30 feet.

Other Gravel Roads

There are numerous gravel roads in the test area with some gravel roads more than 50 miles in length. A variety of aggregate overlay and base are available.

Asphalt/Paved Roads - Public

Within a 60-mile radius are five major federal highways including Interstate 80 as the primary east-west test route. Linking these major highways are ten connecting state routes. On these roads, conditions vary from 50-mile straight and level stretches in the valley floor to curved or straight grades up to 8 percent traversing the mountain ranges. Low traffic density allows for optimum controlled conditions.

Side Slopes

Prepared and natural side slopes up to 40 percent are available on the facility. Base materials include compacted clay/loam and/or crushed basaltic rock. Prepared slopes include 10, 20, 30, 35 and 40 percent with lengths up to 500 feet.

Gradeability Slopes

Prepared slopes include 5, 10, 20, 30, 35, 40, 50 and 60 percent on sand, sandy/clay/loam or basaltic rock base. Natural grades are available up to 70 percent. Length of grades vary from 200 to 750 feet. There are also asphalt slopes and concrete ramps built to support gradability and parking brake tests.

Simulated Loading Ramp

A 35-foot concrete ramp is available. This ramp has a 30 percent grade.

Bridging and Ditch Profile

Ditches from 3 x 4 feet to 6 x 12 feet are used in tests to examine mobility characteristics. Ditch areas are simply modified to provide the necessary basis for evaluation.

Frame Twist

A unique area of similar design to the wave course, this course combines the evaluation of the angle of approach and vehicle flexibility. Frame twist excursions have been established and utilized in previous durability tests.

Turning Circle Test Area

There are two turning circle measurement areas. One is an asphalt section of 10,000 square feet. The other is a level, hard-packed clay area which can accommodate any vehicle size.

Single Event Impact Course

The test course is approximately one mile long and has a random assortment of naturally occurring chuck holes. Approximately 30 chuck holes are found in the hard-packed clay/basalt road bed. Although this is a natural phenomenon, the ground is sufficiently packed so that the chuck holes have relatively constant depth throughout the test. Average depth is 4 inches with a slope of 40 to 75 degrees. Additional chuck holes can be dug to meet test requirements.

Quarry

This area not only provides fill material, but is utilized in tests on all types of loader construction equipment. Three different surfaces within the pit (sandy/loam/clay, 3/4" to 2" basaltic rock in sandy clay; and 2" to 3" sharp basaltic rock embedded in sandy clay) provide useful tire durability information.

Coral Spike Test Area

Approximately 30 square miles of sharp volcanic spikes was classified by the U.S. Transportation Corps in l960 as the only simulated Pacific Coral test area in the United States.

Abrasive Mud Traction

This is a test area with controllable moisture content designed to accommodate any vehicle size. The course length is variable, depending on requirements. Course material is sandy/clay/loam with a hardpan clay base. Mud depth and cone index readings are available to suit specific test requirements.

Clay/Mud Traction

This course is similar to the abrasive mud traction area except for the soil condition. The soil is composed of a fine-grained clay material with a hardpan base.

Four Mile Flat

This test area consists of 32 square miles of inorganic fine-grain clay utilized for both traction and "go, no-go" mobility determinations. Specific test areas, ranging in cone index from 75 down to 5, are available.

Facility Marsh

This course consists of 100 acres of fresh-water-fed test areas with elevation changes up to 100 feet. The soil base is sandy/clay/loam. Downed timber, grasses, standing water, and heavy plant growth are prevalent.

Lahontan Marsh

The marsh and swamp mobility evaluation area is located at the east edge of Lake Lahontan Reservoir. The soil base is clay with a variable cone index. Vegetation of heavy to tropical density is found on this course. Certain portions of this test area are accessible to high mobility vehicles only.

Stream Fording

Five primary fording areas have been established in the Carson River. Although each has a different depth, all have solid packed rock, gravel and sand bases and can be excavated to provide required depths. A variety of natural and prepared ingress and egress courses with slopes up to 70 percent can be found in the fording areas. River bank materials include fine-clay soil, river rock and sand. Vegetation and natural obstacles are available along the 7.5 miles of deeded river area. Course lengths vary from 100 feet to one mile.

Static Water Fording and Leakage Evaluation

Two primary test areas have been established. The first is the NATC salt water fording trough, which is 14 foot wide by x 100 foot long, concrete base trough with 10% ingress and egress slopes. The fording trough can be filled with various controlled salt solutions to seawater conditions and the height of the trough is sufficient to allow water depths up to 60 inches.

The second area comprises natural narrow bays at Lahontan Reservoir and provides shallow and deep water fording. Coarse sand is primarily lake bottom material. Ingress and egress slopes up to 60 percent are available.

Stone Peck Abrasion

This course provides 3/4 minus gravel typical of American Association of State Highway and Transportation Officials (AASHTO) low volume road surfaces. This gravel is selected for its sharp faceted surfaces and is monitored regularly. The gravel is typically thrown up by the tires and can initiate pits in the painted surface, producing sites where corrosion can initiate on the vehicle's base metal.

Grit Trough

This event introduces small particles that can enter various crevices and exposed components within the test vehicle. These particles trap moisture and corrosive materials increasing time of wetness underneath the accumulated grit and keeping contaminants against the surface of the vehicle. Further, the grit trough produces abrasion to various exposed underbody surfaces and coatings. The grit trough incorporates clay and sand particles, as well as sodium chloride and calcium chloride. The base of the grit trough is concrete so that the vehicle can travel through the trough at various speeds and splash the grit material onto the underneath and sides of the vehicle. The course is approximately 200 feet in length with sloping entrance and exits on each end. Grit depth is maintained at 8 inches and 4 inch height alternating bumps are present in the trough to induce body flexing and twisting in the test vehicle.

Salt Splash Trough

This event is designed to simulate the typical splash and spray which occurs when vehicles are operated on winter roads that have been salted as part of road maintenance. The trough consists of a concrete bottom with the ability to adjust the depth of the salt-water solution. The vehicle speed can be adjusted to simulate the appropriate spray. This is a low to moderate speed event with the salt bath having a controlled solution prepared in accordance with customer specifications and a maintained depth of 8 inches.

Halo Spray Trough

The spray bar and reflect curtains of this event ensure that the sides, roof, undercarriage and hood of the test vehicle are exposed to rain and spray conditions typical of operation during storage/transport and embarkation/disembarkation from military landing craft, as well as parking/storage near shore areas. The trough consists of a concrete bottom with the ability to adjust the depth of the salt-water solution. This is a slow speed event. The controlled solution is prepared in accordance with customer specifications and the spray bar is height adjustable to account for different vehicle sizes.

Underwater Fording

Underwater fording tests can be accomplished in the same areas as those described above.

Amphibian Ramp

Several concrete and asphalt ramp areas are available at Lahontan Reservoir. These ramps are not necessarily required for vehicle entry to the lake.

Shallow and Deep Water Swimming Areas

Lahontan Reservoir, which has 155,000 acre-feet and a depth from as little as 5 feet to more than 50 feet, provides a significant swimming capability evaluation test area. Both calm and wave (1-2 feet) conditions are available.

These test areas are on or within a 60-mile radius of the main NATC facility. In more than 36 years of vehicle operation, NATC has yet to be unable to meet a client's test area requirements. If an area does not exist in natural conditions, it can be constructed or simulated.