Aircraft Design Elements
This aircraft was designed around the concept of producing a new generation FAR part 103 (A legal ultralight vehicle). As well as a light aircraft that could be built and flown under the FAA rules governing experimental amatuer built aircraft.
The EMG-5 solves many of the problems that plagued the ultralight aviation community for many years. See how we address the problems of noise, reliability, transportability, and cost while presenting an aircraft that is much more friendly to the environment. green
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As anyone that has designed their own airplane knows, one of the the biggest challenges is excepting the compromises required in order to achieve the design goals. Our design Goals.

1. Meet FAR part 103 rules.
2. Tricycle landing gear.
3. Electric powered aircraft.
4. A safe aircraft.
5. Good performance.
6. Folding wings.
7. Low-cost.
8. Simplified construction.
9. Aesthetic design.
10. A marketable product.

 
Designing an aircraft that meets a few of these criteria is relatively simple. It has been done time and time again in the experimental aircraft world as well as the ultralight world. However meeting all 10 of these design goals is an infinitely more challenging endeavor.
 
The largest challenge by far in designing and FAR part 103 aircraft is the two diametrically opposed rules. The first rule restricting the empty weight of the aircraft to no more than 254 pounds. And the second rule restricting the maximum stall speed to 28 mph. When computing the stall speed for an aircraft at a gross weight of approximately 550 pounds the requirement for the total wing area is approximately130 ft.² for a high-lift airfoil. For a conventional airfoil, the wing area is upwards of 150 ft.². With this much wing area, it becomes very difficult to keep an aircraft with in the 254 pounds required by Part 103. Even though the design goals incorporate the design to be able to be built as an experimental amateur built aircraft which will allow for a significantly higher performance aircraft that has capabilities beyond what a FAR part 103 aircraft will be capable of. We believe that the ultralight market will be the testing grounds for the first generation of electric powered aircraft. drw
 
flps We have tackled this problem in a very unique way. The aircraft has a wing area is merely 105 ft.². In a conventional aircraft this would produce a stall speed of nearly 40 mph. However the advantages gained in producing a light weight weight wing are substantial. In order to start whittling away at the stall speed we have incorporated a 6 foot Fowler flap on each wing. This will increase the coefficient of lift of this wing section well above 2.0. These large Fowler flaps also create a large negative pitching moment which on a conventional aircraft can only be overcome with a significant downforce on the tail section. This downward force is contrary to the positive lift that we are trying to create. And as a result we lose 30 to 40% of the positive gains.
Once again our unique design resolves this problem by the use of thrust vectoring motors. these motors are placed well ahead of the center of gravity. These thrust vectoring motors are capable of 199 pounds of static thrust. And will be able to be placed at an optimum angle to counteract the negative pitching moment from the flaps and in addition counteract any negative pitching moment created by the use of down elevator. This will allow the use of down elevator to produce an additional lifting surface for the purpose of meeting the 27.6 MPH stall speed requirement. In summary we have two engines producing 200 pounds of vertical thrust, Fowler flaps, 105 ft.² of wing area, a lifting body fuselage, and a lifting tail configuration. We are currently working under the principle that FAR part 103 allows both helicopters and auto gyros to operate as legal ultralight aircraft. Since our aircraft is a hybrid version of a powered lift aircraft we are alowed to use power to achive the 24 knt power off stall speed. Our initial inquiries with the FAA have concurred with our conclusions.
forces
Now I'm sure you're thinking that this is a completely unmanageable process by which to fly the aircraft at slow speed. However the purpose of our design is simply to meet the requirements of FAR part 103. Initially we will only have to demonstrate that the aircraft is capable of flying at these speeds. There is no requirement that the aircraft actually be operated during normal operations in this configuration. Initialy conventional operations will be the norm utilizing a stall speeds of 34 mph. and 40 mph. respectively.With this in mind you can project that in the future we will be capable of flying the aircraft with the use of current state-of-the-art gyro technology utilized by the model industry to fly the aircraft not only below the 27.6 mph speed, but initial calculations project slow flight capability in the neighborhood of less than 20 knts.

Future Design Goals:

1. Gyro stabilized pitch control.
2. Gyro stabilized yaw control.
3. Regenerative motor capability.
4. In-flight adjustable pitch propellers.
5. In-flight foldable propellers.
6. Solar cell wing covering.
7. Reverse thrust.
8. Vectored thrust short field takeoff.
9. Vectored thrust taxi maneuvering.

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The aircraft is designed with a wing of aproximally 105 ft.² in area using a modified Wortman FX 61–163 airfoil with nearly 6 foot of Fowler flaps on each inboard section of the wing. The choice to use this airfoil was based primarily on performance and the proven track record on many other gliders. In addition the large flat sections located at the apex of the airfoil coincided with the structural requirements of the main spar. This geometric consideration made it possible to design the wing with a minimum of weight and design simplicity.

http://www.ae.illinois.edu/m-selig/ads/coord_database.html

http://www.worldofkrauss.com/foils/1002

 
Design Methodology
The EMG–5 design was driven primarily by the goal to keep the aircraft as light as possible in order to meet the FAR Part 103 limitation of 254 pounds. The over riding philosophy was to utilize components within the aircraft to do as many tasks as possible, eliminating the necessity for multiple, large structural components doing individual jobs. The positioning of the pilot directly over the main spar eliminates much of the structure related to ergonomics and seating. The main spar is also the primary attach point for the main landing gear position in both landing loads and flight loads using the same structure. An aluminum boom tube fuselage was utilized in order to reduce weight and drag around the aft fuselage section. The use of carbon fiber construction on all compound curved surfaces reduces weight while increasing aerodynamic efficiency. 8
The fuselage primary structure is manufactured from 2020 4T3 aluminum. The sides and the belly which are the primary structures are designed as a flat plate surface in order to facilitate both simple and low-cost construction. The windscreen is also manufactured as a divergent shape single curved surface windscreen which allows for the manufacturer from a single piece of Plexiglas. This will reduce the cost of manufacture as well as ensuring quality optics typically associated with low-cost molded canopies. The overall shape of the fuselage retains an exceptionally clean low drag profile. The transition from windscreen to fuselage remains tangent to the smooth curve of the aft fuselage. The pilot compartment is a compromise between minimal drag and pilot comfort. The shape of the fuselage acts as an airfoil creating a low pressure area directly around the wing transition adding significantly to the total lift of the aircraft
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All curved surfaces on the fuselage including the nose cone, wing fillet fairings, upper fuselage shell, aft fuselage shell are manufactured from carbon fiber.For the canopy design, we opted for a frontal design that retained good aerodynamic characteristics, yet allows for the use of flat panels for all of the canopy. The top windshield is a flat curve allowing for the use of a flat piece of Plexiglas wrapped into the shape of the canopy. This reduces the cost of manufacturing and even a construction process that the average builder can be successful with. The optics associated with blown canopies can often times be very distracting especially if the process and molds for the canopy over a compound curve are not tightly controlled. High quality canopies often times can add $2000-$5000 to the cost of construction. We have even seen some high-performance glider manufacturers charging prices in the neighborhood of $20,000 for a replacement canopy. The use of flat panels reduces the cost, and complexity. And allows for high-quality optics, ease of maintenance, and low cost replacement. When the large surfaces such as the upper canopy are bent around a curve the rigidity improved substantially allowing for much thinner and lighter weight sections of Plexiglas. Additionally, from the standpoint of enjoying your flight, visibility can be a significant factor and this design allows for maximum visibility.
11 Every component on the aircraft is weighed during the manufacturing process to validate the data being generated by Solid Works as well as validating our construction methods and techniques.This picture of the nose cone weighed 17.7 ounces as it came out of the mold and final trim weight once fitted to the aircraft was 15.5 ounces.All of the fairings on the aircraft are nonstructural with the exception of the upper fuselage shell. This allows these components to be manufactured extremely light weight.
 
Electric powered aircraft
12 The electric powered design goal is an integral part of the project. Electric powered aircraft are the future of aviation.
Since changes in both the electric motor technology, as well as the more important battery technology, will continue to change and improve at an ever-increasing pace. Therefore, the design choice to place the motors on an articulating pod located outside of the aircraft was based on the simplicity associated with choosing different powerplants, and upgrading as time goes on. The electric motor that we have chosen for the prototype aircraft is called a predator 37. This motor is made by Plettenberg in Germany. And is manufactured for the giant scale radio control aircraft industry.
 
In this picture you can see the motor configured with the front spinner, motor mounts, blade hub holders, blade hubs, and carbon fiber propeller blades. The weight of this entire assembly less than 5.5 pounds. The motor was reconfigured to allow the use of ground adjustable propeller blades. All of the aluminum CNC components that are anodized blue as well as the red hub attachment parts were manufactured in-house and are designed specifically for the prototype aircraft so that we may test different flight characteristics using different blade pitch configurations. We have already started design work on in-flight adjustable blades as well as a folding blade design. 13
 
14 Content for New Div Tag Goes Herethe electric motor is a classic out runner design we have configured the center hub with a spinner and a standoff to assist in cooling through the central core of the motor. Each motor is capable of 16 hp and 99.3 pounds of static thrust using these propeller blades. We have found many other motor manufacturers that look promising which will in the future give us many options. The primary intent for pylon mounted motors was to allow for easy retrofit depending on state of the current technology. Understanding that this technology is evolving very rapidly makes the necessity to be able to adapt essential.
Currently the aircraft is designed as an electric motor glider where the batteries and motor can be used in one of many different capacities. 1) As a self launch mechanism to propel the aircraft through a climb to 3,000 to 6,000 feet at which point the aircraft simply operates as a glider. 2) Since the aircraft is a true glider it can be towed aloft, or towed from the ground behind a vehicle, or a winch. At which time the engine can be used simply as a sustainer. 3) With additional batteries the aircraft can be used similar to a conventional aircraft capable of cross-country flight.
Retractable landing gear
As in most aircraft the landing gear provides a significant set of compromises. In this case the necessity for a low drag profile was the overriding factor. In order to have an aircraft that will meet the criteria for the definition as a glider, drag plays one of the more significant roles. The choice of a retractable landing gear opposes several of the other design goal criteria, primarily simplicity, low cost, and lightweight.
Most gliders solve the low drag problem by either eliminating the wheels altogether or providing in-line retractable wheels. We felt that an aircraft that was configured as a tricycle landing gear system would be better suited for the overall market and easier to handle for newer pilotsThe tricycle landing gear configuration allowed us to have a mobile aircraft that could be maneuvered with the wings in the folded configuration. Additionally the tricycle landing gear configuration allowed us to make the aircraft trailerable.
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16 Our focus groups during the original design process had commented on a desire for a very wide stance landing gear. Some of the early designs like EMG-1 and EMG-2 had a relatively narrow gear. The gear had to be positioned within the confines of the structural section of the main spar allowing the wing fold to not interfere with the landing gear during the wing fold process. Additionally the landing gear could not be placed on the wings as the wings folded. The aircraft was designed to be able to be rolled into an enclosed trailer and the gear position so that it would roll between the wheel wells of a conventional trailer.

Landing gear is designed as a cable operated system using a failsafe freefall self locking down lock mechanism. The landing gear legs themselves were manufactured from 7075 – T6 billet aluminum with the final weight of each gear legs weighing 3.5 pounds. A fixed landing gear seems possible only after the energy density of batteries improves to the point that it makes it practical to fly the aircraft primarily as an powered aircraft. We have plans to develop an additional design landing gear that will be simpler and less costly. The low cost landing gear legs will be manufactured from 4130 chrome Molly steel tubing. 17
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In this YouTube video you can see the design process by which the landing gear was designed, stress tested, and solid cam machine code generated for producing the actual landing gear legs. In this video you can see both the rough cut and the finished cut using a high-speed machining process toolpath that was simulated using solid cam before the actual part was cut.

Click on the picture to the left or this link to take you to the YouTube video.

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In this YouTube video you can watch the actual landing gear being cut using a CNC milling machine. This is a rough cut of the second side of the landing gear.

Click on the picture to the left or this link to take you to the YouTube video.

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In this YouTube video you can watch the finished cut of the first side of the landing gear

Click on the picture to the left or this link to take you to the YouTube video.

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The complexity and the weight of the nose gear were improved primarily by making the nose wheel non-steerable. As with most gliders that incorporate a nose wheel the necessity during normal glider operations is minimal. For maneuvering the aircraft we incorporate individual brakes on each main landing gear wheel and because we have the ability to position the motors and vectored thrust upward on the nose gear the weight on the nose gear during taxi can be offset and controlled by lifting the nose of the aircraft off the ground. Future plans involve using Gyro stabilization thrust vectoring to hold the nose just slightly off the ground during taxi for easy maneuvering. On the part 103 aircraft utilizing the Azuzsa wheels and no brakes seems to be a viable option depending on where the aircraft is to be operating.
Low cost of Construction

The EMG-5 design significantly changes the paradigm on how lightweight recreational aircraft can be built. The aircraft plans will be available in their entirety via the website. A annual fee will allow the builder to have access to all of the plans to build the aircraft. Even though the design of this aircraft utilizes some very sophisticated state-of-the-art computer modeling, engineering, and design software, our goal is to provide builders with the option to build the aircraft with as little outside help as a builder chooses while providing all of the parts, including kits, to builders who wish to accelerate the process. As the project progresses, we will strive to provide alternate means of construction to allow for even more of the parts to be built at home by an amateur builder. Additionally, we are working on articles, videos, and drawings that will assist in the construction of the aircraft. Check the projected schedule listed on the website for estimated availability.
Folding Wing

The Elanus EMG-5 was designed with the intent that the owner of this aircraft would be working with a limited budget. The ability to fold the wings and trailer the aircraft when the aircraft is not in use allows the aircraft to be stored in a single car garage or a trailer. With the wings and the folded position the aircraft is 21' 6" g standing only 4' 10" high and less than 8 feet in width.

The wings hinge at the main wing spar and are secured with a bolt on the forward spar.

All flight controls are automatically connected and disconnected during the wing fold process.

Removable fairings aft of the fuselage main spar allow the wings to retract with out any interference from the fuselage.

The aircraft is fitted with a fiberglass tail wheel and leaf spring which supports the weight of the aircraft when the wings are folded preventing damage and allowing for easy maneuvering.

Tail will also acts to prevent the elevator from touching the ground during high angle of attack low-speed landings or the elevator hitting the ground when the controls are in the fold-down position during taxi and or being parked.

 
side

The concept of a roadable aircraft is not without its merits.Our aircraft design has a total width of less than 8 feet.

This makes the ability for the aircraft to be transported on a trailer or even driven down a street to your house a possibility.

The actual ability to use the aircraft as a truly roadable aircraft is a completely different problem. The Terrafugia Aircraft has been leading the way and breaking down some of the barriers to a truly roadable aircraft.

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BRS Balistic Recovery System
   
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The aircraft is designed to be fitted with a ballistic recovery parachute system.

The hard points are built into the design directly in line with the main spar. And secondarily attached to the pilot.

Several mounting locations are being analyzed at this time. Currently the preferred location is a soft pack installation located within the entrance hatch. A soft pack installation will be possible because of its location with in the interior of the aircraft.

Click on this link to see a video simulation of the BRS in action.

 

 
 
Below is a comparison between a standard class glider and the EMG-5. We will use the Schempp-Hirth Discus is designed by Schempp-Hirth. It was produced in Germany between 1984 and 1995 but has continued in production in the Czech Republic. The following specifications compare the two aircraft
  • Discus

  • Crew: One pilot
  • Length: 21 ft 7 in
  • Wingspan: 49 ft 3 in
  • Height: 4 ft 3 in
  • Wing area: 113.9 ft2
  • Aspect ratio: 21.3
  • Empty weight: 510 lb
  • Gross weight: 1,160 lb
  • EMG-5

  • Crew: One pilot
  • Length: 18 ft 7 in
  • Wingspan: 35ft 9in
  • Height: 5 ft 3 in
  • Wing area: 105 ft2
  • Aspect ratio: 12.3
  • Empty weight: 254 lb
  • Gross weight: 650 lb
discus
For information on how this project is proceeding referred to the status page. Each month we create a progress page to highlight the progress that is being made on the project. The progress page itself will help keep track of the changes that are occurring within the website. This should be helpful as we anticipate that there will be close to 10,000 documents and pictures relating to this project
 
 
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The information contained in this web site is subject to change without notice.

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