Mechanical Projects

Development of a Dynamic Test Facility for Environmental Control Systems

Passenger cars and light trucks consume 80% of the total oil imported by U.S.A. Mobile air conditioners (MACs) increase vehicle fuel consumption and exhaust gas emissions. They operate most of the time in a transient state.

It is currently impossible to test the performance of an air conditioner during transient operation without it being associated with its intended conditioned space, the car cabin. In this research work a new smart test facility is designed, built, and verified. This facility makes it possible to test the MAC independent of the vehicle, but yet under realistic dynamic conditions.

The facility depends on simulation software that measures the conditions of the air supplied by the MAC and subsequently adjusts the conditions of the air returning to the MAC depending on the results of a thermal numerical model of the car cabin that takes into consideration sensible and latent loads, as well as passengers’ control settings. It was successful in controlling the temperature and relative humidity within ±0.9°C and ±5% of their respective intended values. The test facility is used to investigate the dynamic performance of a typical R134a MAC system. The tests include pull-down, drive cycle, and cyclic on/off tests.

The analysis focuses on the latent capacity and moisture removal due to the difficulty in measuring these variables during field tests. The results show that the most energy efficient method to pull-down the air temperature inside a hot-soaked cabin is to start with fresh air as long as the temperature in the cabin exceeds that of the ambient and then switch to recirculated air. The effect of re-evaporation is illustrated by showing the off-cycle latent capacity. Cyclic tests show that the net moisture removal rate has a minimum at around a 2 minute duty cycles.

This implies a means of controlling the coil latent heat factor by varying duty cycle. The automotive air conditioning system is numerically modeled and used in cooperation with the cabin model to conduct numerical tests. The numerical simulation results are compared to the experimental results and the error is less than 1.5 K of cabin air temperature.
Source: University of Maryland.

Life Consumption Monitoring for Electronics:

Life consumption monitoring is a method to assess product’s reliability based on its remaining life in a given life cycle environment. The life consumption monitoring process involves continuous or periodic measurement, sensing, recording, and interpretation of physical parameters associated with a system’s life cycle environment to quantify the amount of degradation.

This project explains a life consumption monitoring methodology for electronic products, which includes failure modes, mechanisms and effects analysis (FMMEA), virtual reliability assessment, monitoring product parameters, data simplification, stress and damage accumulation analysis and remaining life estimation. It presents two case studies to estimate the remaining life of identical circuit card assemblies in an automobile underhood environment using the life consumption monitoring methodology.

Failure modes, mechanisms, and effects analysis along with virtual reliability assessment is used to determine the dominant failure mechanism in the given life cycle environment. Temperature and vibration are found to be the environmental factors, which could potentially cause malfunction of the circuit card assembly through solder joint fatigue. Temperature sensor and accelerometers are used along with a data logger to monitor and record the environmental loads during the experiment.

A data simplification scheme is used to make the raw sensor data suitable for further processing. Stress and damage models are used to estimate the remaining life of the circuit card assembly based on the simplified data. Performances of the test board assemblies are monitored through resistance monitoring. The life cycle environment and results for the case studies are compared with each other. The estimated results are also compared with experimental life results.
Source: University of Maryland.

Camera Spectral Sensitivity Characterization using a Blackbody Source :

With digital cameras emerging as more effective tools for scientific research, there is increasing need for accurate and inexpensive ways to calibrate them. In particular, to date there has been no simple method to measure camera sensitivity as a function of wavelength.

For example, narrow bandwidth monochromator beams are expensive and have calibration problems, while color chart method is unreliable owing to illumination dependence. This thesis presents a novel technique for spectral sensitivity calibration of a camera (or any black-and-white cameras or color sensors) using blackbody furnace operating at 650 – 1250 °C.

Images recorded at 11 different temperatures are observed for red, green, and blue camera outputs. Using Planck ’ s Law to calculate the incident light intensities, the three color sensitivities as functions of wavelength are computed using MATLAB function that optimizes the spectral sensitivities until the blackbody measurements are closely matched. The results are in reasonable agreement with published sensitivities.
Source: University of Maryland.

Vehicle Handling, Stability and Bifurcaiton Analysis for Nonlinear Vehicle Models :

Vehicle handling, stability, and bifurcation of equilibrium conditions were studied using a state vector approach. The research provided a framework for an improved method of vehicle handling assessment that included non-linear regions of performance and transient behavior.

Vehicle models under pure lateral slip, constant velocity, and constant front steer were developed. Four-wheel, two-axle vehicle models were evolved from simpler models and were extended to include vehicle roll dynamics and lateral load transfer effects. Nonlinearities stem from tire force characteristics that include for tire force saturation. Bifurcations were studied by quasi-static variations of vehicle speed and front steer angle.

System models were expanded, assessing overall stability, including vehicle behavior outside normal operating ranges. Nonlinear models of under steering, over steering, and neutral steering vehicles were created and analyzed. Domains of attraction for stable equilibrium were discussed along with physical interpretations of results from the system analysis.
Source: University of Maryland.

Steering & Gears

1-1  Principles of Steering

One of the most interesting features on a wheeled vehicle is the steering system. The steering system consists of all the parts necessary to make the front wheels turn in the direction we wish to go. These parts include a steering wheel, a gearbox, and all linkages and levers needed to control the front wheels.

Steering systems are carefully designed so that the driver can, without too much effort, keep the vehicle going straight ahead or turn it to the right or left. The driver must be able to easily overcome the tendency of the front wheels to go to the right or left as a result of striking holes in the road, rocks, stumps, or other obstructions. Obstructions try to stop the wheel that strikes them, while the other front wheel tries to keep rolling, which causes the vehicle to turn in the direction of the obstruction. This is called road shock. Road shock tries to jerk the steering wheel out of the driver's hands. Hitting obstructions makes it difficult to control the vehicle, and steering systems are designed to reduce the shock caused by striking obstructions.

Another feature of the steering system is the front-wheel alignment, which is referred to as steering geometry.

Front-wheel alignment can be defined as the proper positioning of the front wheels to make them easy to turn to the right or left and to reduce the tendency of the tires to scuff or wear unevenly. Proper alignment also reduces the tendency of the front wheels to wander or shimmy and makes it much easier to control the vehicle.

FIGURE 1.   ACKERMAN STEERING SYSTEM.

FIFTH WHEEL STEERING

Remember the toy wagon you played with in your younger days? To steer the wagon you merely pulled the wagon handle to the right or left, and the axle and both front wheels turned with the tongue. The axle was a single shaft with a wheel mounted on each end. There was a pivot at the center so the axle could be turned to change the wheels from the straight-ahead position. This type of steering arrangement is known as fifth wheel steering.

Fifth wheel steering is commonly used on towed vehicles, such as semitrailers pulled by tractor-trucks. The lower part of the steering pivot or fifth wheel is mounted over the center, and slightly to the front, of the rear axle of the tractor. It has a kingpin lock to hold the kingpin or pivot pin of the semitrailer in the center of the fifth wheel.

Usually, the lower fifth wheel is mounted on the tractor with two pivot shafts. One shaft is positioned crosswise to the tractor; the other, lengthwise. This allows the lower fifth wheel to tip at various angles to the tractor chassis, keeping the bearing surfaces of upper and lower halves of the fifth wheel in firm contact as the tractor and trailer travel over unlevel roads.

The upper part of the fifth wheel consists of a pickup plate and kingpin secured to the bottom front of the semitrailer. A groove around the kingpin allows engagement of the kingpin lock.

When the semitrailer is connected to the tractor, the bottom of the trailer is higher than the tractor wheels. This is necessary because, as the truck and trailer make a turn, the entire rear axle and wheel assembly pivot under the front of the trailer frame. On a very sharp turn, the wheel on the inside of the turn will move to about the middle under the trailer chassis. Clearance must be provided for the wheels.

FIGURE 2.   FIFTH-WHEEL STEERING.

ACKERMAN STEERING

The fifth-wheel method of steering is not suitable for steering a modern car or truck. The vehicle chassis would have to be too high off the ground to provide clearance for the front wheels. Cars and trucks use a different front wheel arrangement. It is called the Ackerman steering method.

With this arrangement, the axle is held at a right angle to the vehicle frame and cannot pivot. The wheels change from the straight-ahead position independently on separate pivot pins or knuckle pivots at the ends of the axle.

We will be discussing only the Ackerman steering method during the rest of this lesson, so let's clarify the terms that we will be using in regard to wheel movements with this method. When we say "the wheels pivot," we mean that they are changed in relation to the straight-ahead position when making a right or left turn. When we say "the wheels rotate," we mean that they turn on their spindles as the vehicle rolls forward or backward.

FIGURE 3.   CENTER STEERING LINKAGE.

STEERING LINKAGE

To make a turn, the driver of a car or truck turns the steering wheel to the right or left. Because each front wheel has its own separate steering pivot, a considerable amount of linkage is needed to transfer the steering wheel movements to both wheels. The steering wheel is located at the top of a steering column. As it is turned, a steering gear at the bottom of the column is operated. The steering linkage is all of the levers, rods, arms, and links used to connect the steering gear to the front wheels. There is wide variation in the amount of steering linkage on different vehicles.

Most vehicles with front axle suspension have a steering linkage arrangement like the one shown in Figure 3. The linkage consists of the pitman arm, which is splined to the output shaft or pitman arm shaft of the steering gear; the drag link, which links the pitman arm to the steering knuckle arm of the left front wheel; two steering knuckle arms, one secured to each of the front-wheel spindles; and the tie rod, which links the two front-wheel steering arms together. The linkage may be arranged so that the tie rod is in front of the axle or behind it.

Rotary motion of the steering wheel causes the pitman arm shaft to move back and forth in an arc, so that the drag link moves back and forth in a straight line. The drag link transmits the movement to the left steering arm to pivot the left wheel spindle and wheel back and forth on the steering knuckle pivots. Pivot movements of the left wheel are transmitted to the right wheel by the tie rod.

The drag link and tie rod are fastened to the pitman and steering arms by adjustable, ball-socket joints that permit swiveling action. Ball-type studs are secured to the pitman arm and the left steering arm. A housing at each end of the drag link receives the balls. Ball-sockets, coil springs, spring seats, and a screw plug in the housings hold the balls. The screw plug can be screwed in or out to tighten or loosen the joint. Lubrication fittings are provided for each joint. Shields hold the lubrication in and keep dirt out.

The tie rod also uses ball-socket joints, but generally they are not adjustable. A spring holds the ball in its seat to prevent slack. The ball of a tie rod end has a tapered shank or stud that fits into a matching tapered hole in the steering arm. The end of the ball stud is threaded and drilled so it can be secured to the steering knuckle arms with a nut and cotter key.

Each tie rod is threaded and screwed onto the tie rod end. A clamp bolt prevents the tie rod from turning once the ends have been installed.

One tie rod end and one end of the tie rod have left-hand threads, and the other tie rod end and the opposite end of the tie rod have right-hand threads. This is so the overall length of the tie rod assembly can be adjusted when aligning the front wheels without disconnecting either tie rod end.

If the vehicle has independent front-wheel suspension instead of an axle, the steering linkage arrangement is different. Two tie rods are required so each wheel can be raised and lowered without affecting the steering of the other. Many different linkage arrangements are used with independent suspension. Some are quite simple, with the linkage consisting of the pitman arm, two tie rods, and the steering arms.

Other common arrangements add an idler arm and drag link. In these arrangements the idler arm is mounted on the right frame rail by a bracket parallel to the pitman arm. The drag link connects the pitman arm and idler arm so that moving the steering wheel causes both arms to swing in the same arc. Each steering arm is linked to the drag link by a separate tie rod. In this arrangement, the drag link may be called a relay rod, pitman arm-to-idler arm rod, and so forth.

Usually, the length of both tie rods can be adjusted independently when aligning the front wheels. The ends on the drag links and tie rods of vehicles with independent wheel suspension are usually not adjustable. On some late-model cars, tie rod ends are lubricated for life when manufactured and do not contain lubricating fittings.

Either threaded or rubber bushings are used at the idler arm-to-idler arm bracket pivot. Threaded-type bushings contain both internal and external threads. The external threads are generally right-hand threads and are screwed into, and tightened in, a threaded hole in either the idler arm or its bracket. The internal threads are generally left-hand threads and are screwed onto the threaded end of the arm or bracket until it bottoms and then backed up one-half to one turn. This leaves the idler arm free to pivot on the inner threads of the bushing.

STEERING GEAR

With the steering wheel coupled directly to the pitman arm by a shaft, it would be very hard for the driver to steer the vehicle. Something must be used between the steering wheel and pitman arm so the driver can gain a mechanical advantage to make steering easier. This is the function of the steering gear.

The principles of steering gears can be demonstrated with a bolt and a nut in the following manner. Screw the nut to the midpoint of the threads on the bolt. Place the end of the bolt against a flat surface so it cannot move back and forth but can be rotated. Hold the nut so it cannot rotate; then, turn the bolt. When the bolt is turned clockwise, the nut is pulled toward the bolt's head. When the bolt is turned counterclockwise, the nut will be moved away from the bolt's head.

Now, if we cut out a section of the nut, attach a shaft to it, and place it against the bolt, we can see how this principle is used in the steering gear. With this arrangement, turning the bolt back and forth will cause the nut section to swing back and forth, turning the shaft with it.

In a steering gear, the part that is like the bolt is called the worm. The worm is secured to the lower end of a shaft with the steering wheel on the opposite end so that the worm and steering wheel turn together. The steering gear part that is like the section of a nut is called the sector, and its shaft is called the pitman arm shaft. The pitman arm is splined to the pitman arm shaft.

The steering gear worm (bolt) and the sector (nut section) are machined so that there is very little lash or clearance between their threads in the midposition. However, as the worm is turned to steer the vehicle either to the right or the left, the amount of lash increases. This makes up for the unequal wear that occurs in normal use. Vehicles are operated in the straight-ahead position most of the time, so most of the wear is in the center of the steering gear worm.

It requires 2 1/2 to 3 1/2 turns of the steering wheel and worm to move the pitman arm shaft through its entire allowable movement, an arc of about 70°. That pivots the front wheels from a hard turn in one direction to a hard turn in the opposite direction. The steering wheel has to be turned farther because of the mechanical advantage gained by the worm and sector. Most steering gears are designed so that they provide more mechanical advantage in the midposition than when turned to the extreme right or left, so they are said to have a "variable" ratio.

Many different kinds of steering gears are used, but they all work in about the same manner.

FIGURE 4.   WORM AND SECTOR STEERING GEAR.

WORM AND SECTOR STEERING GEAR

This type of steering gear looks a lot like our bolt and nut, but the sector of this type looks like a gear instead of a nut. The teeth of the sector are machined in an arc, or curve, so that they actually look like a section of a gear.

As the steering wheel and worm turn, the worm pivots the sector and pitman arm shaft. The sector pivots through an arc of 70° because it is stopped at each extreme when it touches the steering gear housing.

The worm is assembled between bearings, and some means is provided to adjust the bearings to control worm end play. The pitman arm shaft is fitted into the steering gear housing on bearings (generally the bushing type, but roller-type bearings are sometimes used). A lash adjustment screw is also provided so that the sector can be moved closer to, or farther away from, the worm gear to control the backlash between the sector and worm threads or teeth.

The worm and sector steering gear is very simple in construction. This makes it cheap to build and easy to maintain. A disadvantage is that it has a lot of friction because of the sliding action between the worm and sector gear teeth.

FIGURE 5.   WORM AND ROLLER STEERING GEAR.

WORM AND ROLLER STEERING GEAR

The worm and roller steering gear is much like the worm and sector, but the sliding friction is changed to rolling friction so that less effort is required to turn the steering wheel. This is made possible by machining the sector teeth on a roller. Friction is reduced even more by mounting the roller on bearings in a saddle at the inner end of the pitman arm shaft.

The worm has an hourglass shape, smaller in the center than at the ends. The hourglass shape makes the roller stay in better contact with the worm teeth at the ends of the worm.

FIGURE 6.   CAM AND LEVER STEERING GEAR.

CAM AND LEVER STEERING GEAR

In the cam and lever steering gear, the worm is known as a cam. The inner end of the pitman arm shaft has a lever that contains a tapered stud. The stud engages in the cam so that the lever is moved back and forth when the cam is turned back and forth.

When the tapered stud is fixed in the lever so that it can't rotate, there is sliding friction between it and the cam. Therefore, on some vehicles with this type of steering gear, the stud is mounted in bearings so that it rolls in the cam groove (threads) instead of sliding.

Some large trucks use a cam and twin-lever steering gear. This is nothing more than a cam and lever gear with two tapered studs instead of one. The studs may be fixed in the lever, or they may be mounted on bearings.

FIGURE 7.   WORM AND NUT STEERING GEAR.

WORM AND BALL NUT STEERING GEAR

Another form of steering gear is called the worm and ball nut. In its operation, this one really acts like a bolt and a nut. A nut is meshed with the worm and screws up and down when the worm is turned back and forth.

These steering gears are also called the recirculating ball type. Both the nut and the worm have round-shaped threads that steel balls fit in. The balls act as a bearing to reduce the friction between the worm and nut. Ball guides on one side of the nut allow the balls to recirculate as the worm turns to screw the nut back and forth on the worm.

The nut has teeth on one side that mesh with the sector and turn the pitman arm shaft back and forth as the nut is moved back and forth. As with all the rest of the steering gears described, the end play of the worm and the backlash between the nut and sector teeth are adjustable.

FIGURE 8.   RACK AND PINION STEERING GEAR.

RACK AND PINION TYPE

In the rack and pinion steering system, the steering gear shaft has a pinion gear on the end that meshes with a long rack. The rack is connected to the steering arms by tie rods, which are adjustable to maintain proper toe angle. As the steering wheel is rotated, the pinion gear on the end of the steering shaft rotates. The pinion moves the rack left and right to operate the steering linkage. Rack and pinion gears are used on small passenger vehicles where a high degree of precision steering is required. Their use on larger vehicles is limited.

FOUR-WHEEL DRIVING AND STEERING

Four-wheel drive

A construction in which all four wheels of the vehicle drive is used on many military vehicles. A universal joint is used at the end of the axle shaft so that the wheel is free to pivot at the end of the axle while being driven through the axle. The end of the axle housing encloses this universal joint and has vertical trunnion pins that act as a steering knuckle pivot. The wheels, mounted on steering knuckles attached to these trunnion pivots, are free to turn around the pivots at the same time they are driven through universal joints on the inner axle shaft. Steering knuckle arms are mounted on the steering knuckles so that the wheels can be turned around the trunnion steering pivots by the steering linkage.

Four-wheel steering

All four wheels can be steered from the steering wheel by connecting the steering linkage of these wheels to the pitman arm. The rear wheels are connected by knuckle arms and a tie rod. Because the rear wheels must be turned in the opposite direction to the front wheels to travel in the same arcs around the center of rotation, the drag links to the front and rear wheel steering linkage cannot be connected directly to the steering gear arm. The drag link to the front wheels must move forward while the drag link to the rear wheels moves rearward and vice versa. To accomplish this, an intermediate steering gear arm is pivoted on the frame side-member near the middle of the vehicle. The drag links are connected to opposite ends of this arm. As it is turned by direct connection to the pinion arm (by means of an intermediate link), the front and rear drag links are moved in opposite directions.

GEARS

Gears may be classified according to the relative position of the axes of revolution. The axes may be

1. Gears for connecting parallel shafts,

2. Gears for connecting intersecting shafts,

3. Gears for neither parallel nor intersecting shafts.

Gears for connecting parallel shafts

1. Spur Gears

Spur gears: Spur gears are the most common type of gears. They have straight teeth, and are mounted on parallel shafts. Sometimes, many spur gears are used at once to create very large gear reductions. Each time a gear tooth engages a tooth on the other gear, the teeth collide, and this impact makes a noise. It also increases the stress on the gear teeth. To reduce the noise and stress in the gears, most of the gears in your car are helical.

Spur gears are the most commonly used gear type. They are characterized by teeth, which are perpendicular to the face of the gear. Spur gears are most commonly available, and are generally the least expensive.

· Limitations: Spur gears generally cannot be used when a direction change between the two shafts is required.

·

Advantages: Spur gears are easy to find, inexpensive, and efficient.

2.   Parallel helical gears: The teeth on helical gears are cut at an angle to the face of the gear. When two teeth on a helical gear system engage, the contact starts at one end of the tooth and gradually spreads as the gears rotate, until the two teeth are in full engagement.

Parallel helical gears

Herringbone gears

(or double-helical gears)

This gradual engagement makes helical gears operate much more smoothly and quietly than spur gears. For this reason, helical gears are used in almost all car transmission.

Because of the angle of the teeth on helical gears, they create a thrust load on the gear when they mesh. Devices that use helical gears have bearings that can support this thrust load.

One interesting thing about helical gears is that if the angles of the gear teeth are correct, they can be mounted on perpendicular shafts, adjusting the rotation angle by 90 degrees.

Helical gears to have the following differences from spur gears of the same size:

• Tooth strength is greater because the teeth are longer,
• Greater surface contact on the teeth allows a helical gear to carry more load than a spur gear
• The longer surface of contact reduces the efficiency of a helical gear relative to a spur gear

Rack and pinion (The rack is like a gear whose axis is at infinity.):

Racks are straight gears that are used to convert rotational motion to translational motion by means of a gear mesh. (They are in theory a gear with an infinite pitch diameter). In theory, the torque and angular velocity of the pinion gear are related to the Force and the velocity of the rack by the radius of the pinion gear, as is shown.

Perhaps the most well-known application of a rack is the rack and pinion steering system used on many cars in the past

Gears for connecting intersecting shafts:

Bevel gears are useful when the direction of a shaft’s rotation needs to be changed. They are usually mounted on shafts that are 90 degrees apart, but can be designed to work at other angles as well.

The teeth on bevel gears can be straight, spiral or hypoid. Straight bevel gear teeth actually have the same problem as straight spur gear teeth, as each tooth engages; it impacts the corresponding tooth all at once.

Just like with spur gears, the solution to this problem is to curve the gear teeth. These spiral teeth engage just like helical teeth: the contact starts at one end of the gear and progressively spreads across the whole tooth.

Straight bevel gears Spiral bevel gears

Hypoid gears (Emerson Power Transmission Corp)

On straight and spiral bevel gears, the shafts must be perpendicular to each other, but they must also be in the same plane. The hypoid gear, can engage with the axes in different planes.

This feature is used in many car differentials. The ring gear of the differential and the input pinion gear are both hypoid. This allows the input pinion to be mounted lower than the axis of the ring gear. Figure shows the input pinion engaging the ring gear of the differential. Since the driveshaft of the car is connected to the input pinion, this also lowers the driveshaft. This means that the driveshaft doesn’t pass into the passenger compartment of the car as much, making more room for people and cargo.

Neither parallel nor intersecting shafts: Helical gears may be used to mesh two shafts that are not parallel, although they are still primarily use in parallel shaft applications. A special application in which helical gears are used is a crossed gear mesh, in which the two shafts are perpendicular to each other.

 Crossed-helical gears

Worm and worm gear: Worm gears are used when large gear reductions are needed. It is common for worm gears to have reductions of 20:1, and even up to 300:1 or greater.

Many worm gears have an interesting property that no other gear set has: the worm can easily turn the gear, but the gear cannot turn the worm. This is because the angle on the worm is so shallow that when the gear tries to spin it, the friction between the gear and the worm holds the worm in place.

This feature is useful for machines such as conveyor systems, in which the locking feature can act as a brake for the conveyor when the motor is not turning. One other very interesting usage of worm gears is in the Torsion differential, which is used on some high-performance cars and trucks.

Flying Windmills Alternative Energy

 Is wind-power energy probably difficult to be directly implemented for batteries of electric cars due to huge electric energy resulted by wind? However, I believe that sooner or later, outstanding engineers will think of conversing huge electricity of wind into proportional electricity for automotive. I am waiting for this. I am so glad for all progress of global technology! Let's talk about windmill!

Probably You have ever seen or heard about the windmill / wind turbine in the fields of wheat in Europe, in the pages of the home, or in the ocean, but now wind power engineers are trying to bring it to an altitude windmills 15000-30000 feets in the air . Taking advantage of 1% of jet-stream wind energy, enough energy can be created advantageously for mankind on earth.


Farm Windmills on the Air:

Sky Wind Power as energy company based in San Diego is building a Flying Electric Generator like a kite weighing 1100 pounds, which it can produce electricity at a very low cost of just 2 cents (dollar) per kilowatt hour (kwh) and it was flown at an altitude of 15,000 and 30,000 feet . Four rotors at points-shaped frame of the letter "H" wbeing able to carry his platform floating in the air like a kite. Electricity created by the rotor-spinning rotor that was sent to earth through aluminum cables tethered to his frame.

Sky WindPower, Flying Farm, Flying Electric Generator

Sky WindPower hopes someday to build a windmill farm to fly.Proposal nicknamed FEGs (Flying Electric Generators) will menmpati airspace area of 200 square miles. Turbines are made of aircraft materials consist of rotor-rotor diameter of 130 feet and weighs 45,000 pounds. FEGs it will function like a helicopter while flying, powered from the earth station until then began to collect wind energy. Vertical stabilizer on FEGs will adjust the rotor at different angles to balance its platform and optimize the speed of the wind.


Helium Balloons Producing Electricity:

Cannadian company, Magenn Power has built Magen Power Air Rotor System (MARS), a helium balloon that contains a rotating wind generator on a horizontal axis and sends an electric current through a cable that can be directly utilized, stored in a battery, or passed to electric transmission lines. MARS flown at lower than FEGs, between 600-1000 feet, and works at speeds from 4 mph to more than 60 mph (miles per hour).

Kite Producing Electricity:

Another idea came from Dr. Wubbo Ockels of the Delft University of Technology in (Netherlands).

This technology is very promising where the materials used are not expensive and its potential to create a very large energy, much less known that the strength of winds at a height in the air hundreds of times more powerful than on the mainland. These kites produce power by pulling a generator at the earth station, which rolls back a collection of the kite when it reaches its maximum height. Also unlike the land windmill, this technology also does not need large area to be operated.

This fantastic kite has an area of 10 square meters and it is capable of generating electricity through a generator of 10 kilowatts (enough for 10 homes). And it is currently being developed in experiments with 50 kilowatt kite and a kite-powered line of 100 megawatt-called "Laddermill" . exploiting that very huge electricity is expected to supply energy to 100,000 homes!
Kite is linked to be lined and it plays in a loop which it creates energy and electrical currents created are sent to earth via a cable along 30,000 feet.

Jet Stream Ram Air Wind Turbine

In earlier posts I have mentioned that a turbine capable of harvesting the energy of jet streams would probably be better for newspaper headlines than for an economical approach to wind electricity, since it would probably be cheaper and more effective to build several smaller low altitude turbines than a single monster that could tap into the jet streams. But it got me to realize that there are no jet stream turbines on the Salient White Elephant. This is Salient, to be sure, but is it White Elephant? Certainly not! And already I can hear not a little hubbub from the Canadian Parliament behind me patting their tables and gushing heah heah! So let’s just round things out with a couple of jet stream turbines before tensions run too high and one of the hairs on the head of the Right Honourable Stephen Harper springs noticeably out of place, shall we?

For some reason, I’m usually biased toward using suction rather than high pressure in my flow accelerator ideas. But one advantage of using ram air pressure in the machine proposed here is that it would keep the long fabric tube inflated. This is very significant of course, since one of the biggest challenges in designing an airborne turbine is keeping weight to a minimum. Using high pressure might eliminate any rib-like supporting structure that would otherwise be required for the tube. I guess you’d have to stabilize the fabric tube by attaching it to the tethering cables at various intervals, but who knows… maybe somebody can design a way around this requirement.

Triple Tethered Variation

Multiple Blimps Variation

There are many variations of the ideas proposed here, but let me discuss one in particular. This idea emphasizes a technique I’d like to use to bring these pie-in-the-sky airborne turbines a little closer to feasible. Imagine eight blimps. Each is tethered by at least three cables to keep the blimps from moving around too much. An aerial view would reveal that the blimps are situated at the vertices of a gigantic octagon. It is important to note that the “diameter” of the octagon is far from insignificant. I can’t give you a number… maybe two or three football fields? Each blimp has a parachute and a high pressure tube, just as described above. All of the high pressure tubes converge at the center of the octagon, where they connect to a single larger high pressure tube that takes the jet stream wind down to the ground.

What’s so great about this variation? Well… let me first list what I believe may be the salient objectives of airborne turbine design:

• If possible, no moving parts in the air.
• If possible, no fiberglass, electrical cable, gearboxes, drive shafts, or electrical generators in the air. (Ever notice how the components of a wind turbine that have to do with mechanical and electrical power are about the most dense (heaviest) things known to engineering kind?!)
• MINIMIZE WEIGHT, MINIMIZE WEIGHT, MINIMIZE WEIGHT!!!!!!!!!!!

So the idea here is that instead of having eight different tubes, we attempt to minimize weight by having a single large tube carry wind from the jet stream to the ground. This is desirable because the really long distance is from the jet stream to the ground. Once at the center of the jet stream octagon, it isn’t much further to the blimps. So could we use this trick to reduce the overall weight of the machine?

Well, whether this trick will work or not… I think you see my point. What is needed is a kind of linear programming style optimization that minimizes weight of fabric per kilowatt of capacity.

Can We Really Reach the Jet Stream?

No. The jet streams are like 30 to 40 thousand feet off the ground. (The cruising altitude of jet airplanes!) So we can’t reach the jet stream with the design proposed in this post. But we can certainly reach a higher altitude than today’s state of the art wind turbines! If you want to see a more practical configuration that uses the principles described in this post, check out the Practical Artificial Pressure Differential Wind Turbine.

Carbon Fiber-Materials

Carbon fiber is a relatively new material to robotics. However, it has already become a very important material, making new robots possible that were not possible before.
Strength
Carbon fiber has a very high strength to weight ratio, meaning that for another material of the same weight, it is likely to be much stronger. But carbon fiber is a fibrous material, meaning that the fibers are all aligned in a single direction. This can affect strength if used improperly.
Because the fibers are aligned, carbon fiber has different strength amounts - depending on the direction that force is applied at. For example, rope is very strong if you pull, but very weak if you push. Carbon fiber is very strong in both compression and tension, but is much weaker in bending (force from the side). It is like trying to break a stick - breaking it at the center is much easier than by pulling it from the sides. So when using carbon fiber, make sure all force is only applied longitudinally.

Weight
Carbon fiber is extremely lightweight for its strength - this is why it is now very common now in hobby RC aircraft and micro-air robots. Some micro-air robot craft were not even possible before carbon fiber! Before it became popular, balsa wood was the prevailing lightweight structural support material. If you are currently using balsa, you should probably switch. Really an amazing material. I used to do research for the CMU NanoRobotics Laboratory and carbon fiber outperformed all other materials for my microrobotic applications.

Other Applications for Carbon Fiber
Carbon fiber is sold in various very affordable shapes: round tubes, square tubes, flat sheets, retangular bars, and a few others. Tubing is usually used for structural support. The flat sheets are used for ant weight battle bot armor and other chassis covering. I have use rectangular carbon fiber bars to make 4-bar linkages (shown in the image at the top of this page). The shape you use will be dependent on how you expect the force to applied, amount of force, and your attachment method.
Carbon fiber has other useful properties as well. Since it is non-metallic, it can be used in applications where metal would interfere with sensors. Medical MRI's (magnetic resonance imaging) machines use very strong magnetic fields, preventing things like surgery robots to be used inside of them. But if you make the robot out of something non-magnetic, such as carbon fiber, that would no longer be a problem. Carbon fiber is already used to make backing boards to tie patients down for things like CAT scans and X-Rays. Why? CAT scan machines detect radiation emission from a radioactive isotope injected in to you. X-Ray machines detect radiation reflected back from you. Metal however attenuates (blocks) radiation, making the sensors useless. Why do you think Superman can't see through lead?




Working with Carbon Fiber
Working with carbon fiber is very easy. You can basically work with it the way you work with wood. But being a fibrous material, you have to be very careful ofsplintering - taking a little practice to master. There are several tools you should keep around for when you work with carbon fiber. Remember, if you choose the wrong tools, your subjecting your carbon fiber to splintering.

A Jewelers Saw can be bought at various jewelry and hobby stores. What makes it good is that it is fine toothed and designed for precision cutting work. If you have a hacksaw with a fine toothed blade that should work. The blade must be sharp and with no damage.

A pair of fine cutting snips for cutting is also highly recommended. These are good for cleaning up a saw cut that has a few remaining fibers that escaped your wrath. For the very thin rectangular carbon fiber, snips can be used instead of a jewelers' saw. Again, make sure this tool is extremely sharp.

For drilling you can use normal drill bits. But if you just drill straight out without first preparing the carbon fiber you will quickly notice splintering and breaking at the drill point. I have tried taping over the area I want to drill to get reasonable results. But you probably also want to paint the area over with a plastic buffer (made from a cheap plastic putty) or soaking the area over in superglue (the running type that can soak in between the fibers) to prevent damage from the drill chuck.
Make sure your drill bit is really sharp (new bits or diamond tipped bits work best) because any roughness will pull at the fibers instead of cutting - hence causing damage. Make sure you drill slowly. After drilling, you want to file away any splintering with fine grain sandpaper and/or scotchbrite. Then coat the finished area with a layer of superglue and let dry. The superglue will hold the loose fibers together and prevent any future damage. Use this method of filing and glueing for when you cut/saw carbon fiber too.
Attaching Carbon Fiber
Attaching pieces of carbon fiber together (or to other materials) can be a little tricky. For attaching sheets and plates it is somewhat easy. You can drill a hole in each and bolt them together. And/or use epoxy or fiberglass resin which you can normally find in repair kits (such as for boats at boating supplies stores). Make sure you work all the air bubbles out of the epoxy mix while it is drying (bubbles are weak spots). For really serious bonds, try an epoxy called Plexus. I have not used it myself, but I hear it is good. For attaching rods together it gets a little tricky. The bolting method using screws works. There are also special plastic connectors sold at various angles where you can just attach both ends of your carbon fiber rods together.
'Molding' with carbon fiber is somewhat complicated, and since I have never done it myself, I wont go into much detail. But basically you buy a bunch of paper thin sheets of it and glue it all together over a mold to become this cool looking custom shaped shell. You will have to do temperature control and layering and all this other complex stuff. Will probably make an interesting alternative to the advantages of vacuum forming if you are willing to attempt it.
Safety
I am actually shocked at how little safety has been paid attention to online for carbon fiber. A Google search for carbon fiber safety tips yielded zero useful results for me. I am no expert on carbon fiber safety, so I will just go through the common sense stuff. So first, lets talk about the dangers of carbon fiber. Carbon fiber is exactly what the name suggests, extremely thin strong fibers. Basically light weight needles capable of jabbing into your skin or worse - capable of becoming airborne and jabbing into your lungs and eyes, etc. Coughed up blood, anyone? You get the idea.
Apparently some people are even allergic to some degree and get skin reactions from it. "It's a skin reaction that looks like a really bad sun burn and itches like a mother." If you plan to saw or drill carbon fiber, expect copious amounts of fine particles to become airborne.

Now protection for carbon fiber should be obvious for you. Above anything else you want a basic $1 face mask for breathing. Probably you want to do this outside with air flow as well. This has been sufficient for me to work with it. But if you require more, like if you are allergic to it, then eye protection goggles, and even a Tyvek suit (such as for HAZMAT stuff, shown in the above image) will work.
Additional Carbon Fiber Notes
UV light can and will break down carbon fiber over time. UV top coat is advised, and gives the parts that nice shiney finish.

Carbon fiber tape looks neat, but I just have not found a use for it yet. Maybe for wings?