Setting the plane configuration

Similar types of planes (check the position of the wings, stabilizers, motor and camera):

Bananahobby.com

Hobbyexpress.com

site.nitroplanes.com

mikeysrc.com/MRC_FPV_Camera_Plane.pdf

sailplanes.flytodream.com

Example of real powered glider design, sysmcape.com

Avinc.com (look for Wasp III, used by US Marines)

 Let’s make the first draft of the plane shape:

The fuselage is going to be as thin as possible, gaining thickness in the front part, where the pilot would be in a large scale glider but instead this place is going to hold the battery and other electronic components such as the PCB, receiver and the camera. The front part must be shaped as much aerodynamically friendly as possible. This wider part is also where the wings will be attached to the body. 

Fuselage width must be sized depending on the battery+PCB+receiver+camera size.

The wings will be placed in a medium height (relative to the fuselage bottom). Each wing will have just one control surface, the aileron, placed on the exterior part to create more momentum and a winglet in case further study proves they increase the aerodynamic efficiency. Ailerons can work as the missing flaps and no airbrakes/spoilers are needed for this plane due to low flight speeds.
Gyroscopes for plane stabilization are another option to be yet determined.
No dihedral or sweep angle is considered necessary at first, improving the manufacturing process.

Further study of spiral mode and stall when climbing or turning.

In the empennage, a high horizontal stabilizer plus elevator configuration will be chosen, to avoid turbulence interference created by the wings.
As in most planes, the vertical stabilizer will be just one vertical part with the rudder at the rear.

No landing gear is needed as it will take-off with the hand-launch technique, but a landing device might be useful to decrease the impact force.
The motor position is more variable in the design. One possibility is to place it at the very front of the fuselage, making possible a direct spool connection. One first idea is to make it bendable with the air flow to reduce drag in case of unpowered flight and reduce the chance of damage when touching the ground.
Another option to avoid motor damage and don’t interfere with the camera is to place the motor on the top of the middle fuselage section. In that case, the empennage configuration must be changed to a low stabilizer and the wings should be moved upper.
The third option is to place the motor at fuselage-height but only with a twin boom configuration, as in this design:

Wikipedia.com (twin-boom aircraft)

But this is a more complex design, so it’s not desirable.

The fourth option is to place is at the very end of the empennage, as in the MQ-9 Reaper UAV:

Wikipedia.com (MQ-9 Reaper)

The last valid option is to use 2 motors, each one mounted on the wing (better below it), so they don’t interfere with the line on sight and they increase the performance of the aircraft. But for a powered glider, one motor is good enough.


Several options are taken into account with a CAD model (using Autodesk Inventor Professional 2011 Free Student Version):

 Placing motor at the front and changing wing configuration:

 Changing motor to the back of the plane to avoid camera obstruction:

Changing motor to the center to increase stability and avoid the camera, which will be placed at the very front, like from the pilot’s view.

Where the motor is placed affects the wings and elevator too, because they must not interfere with each other in stabilized flight.
If the engine is at top height, elevator must be at the bottom so the turbulence from the air passing through the engine doesn’t affect it.
The wings turbulence mustn’t affect it either, so wings will be placed at top height of the fuselage, just before the engine so they don’t interfere.

(Fuselage is yet to be shaped in order to carry the payload while creating low drag)

With the shape almost fixed, the size is the next thing to be determined.
An important parameter to be taking into account is the transportation of the airplane. It must be designed to fit in an average car. It can have less wingspan and length than that of a car’s interior or it can be disassembled into several pieces (dividing the fuselage in two parts or cut out fuselage and wings).
These are the most restrictive dimensions, restricted by the manufacturing process, not by transportation means.
         

 Dimensions in mm

To fit in a car it should be around 2.5 meters wide and around 1 meter long.  This is the most compact possible way it could fit, but still doesn’t.

Either it is reduced or dismantled before travel.

Index and first ideas

This is the index of the project's process:

Preliminary design:

• Background
• Similar aircrafts
• Objectives and specifications

Calculations:

• Take-off weight
• Polar
• Performance
• Wings
• Empennage
• Fuselage
•  Centering
• Static and dynamic stability
• Materials
• Flight control system
•  Economic study

Analysis:

• Solid modelling (NX Unigraphics)
• CFD (Vortex Lattice, XFLR5, ANSYS Fluent)
• Structural analysis (ANSYS Structural and Composite PrePost)

Manufacturing:

• Materials
•  Mold
• Machining
• Assembly
• Finish

Flight tests


______________________________________________________________________________

(Written on October 17, 2014)

First steps, conceptual design:

For the aircraft design several ideas are going to be taken from many different designs of RC planes in the market.

This is to start modelling the fuselage form and the aircraft configuration for the wings, empennage and power plant.

The specification of this plane is for recreational flight, nor acrobatic neither competition. One important characteristic is the high aerodynamic efficiency, with increased wing surface to act as a glider when it has gained altitude.
Another possibility to be studied is the implementation of a camera in the fuselage to transmit live the view from the cockpit, which can be seen in a screen in the controller. The maximum wingspan is set to 3 meters because of manufacturing reasons. The plane has a constant weight payload consisting of the signal receiver, the battery, the control system (PCB, servomechanisms, gyroscopes) and an electric motor. This engine can be used for climbing or retake flight in case of stall or quick loss of altitude.
High aerodynamic efficiency allows a slower flight speed, better for professional aerial filming, and it counteracts the effect of adding a camera on the fuselage, which creates a lot of drag. If the purpose is to record the view, larger wings make it more steady, regardless of using the motor or not.

The point is for increasing its versatility. It mixes the advantages of a glider to an RC and it also adds the multiple uses of a first-person view flight. Away from the plane, a radio transmitter system will be needed too.

Wikipedia: “Powered gliders have recently seen an increase in popularity. By combining the efficient wing size and wide speed envelope of a glider airframe with an electric motor, it is possible to achieve long flight times and high carrying capacity, as well as glide in any suitable location regardless of thermals or lift. A common method of maximizing flight duration is to quickly fly a powered glider upwards to a chosen altitude and descending in an unpowered glide. Folding propellers which reduce drag (as well as the risk of breaking the propeller) are standard. Powered gliders built with stability in mind and capable of aerobatics, high speed flight and sustained vertical flight are classified as 'Hot-liners'. 'Warm-liners' are powered craft with similar abilities but less extreme thrust capability. Many powered beginner craft are based upon or considered borderline gliders.”

A good use a sailplane with a camera could have is to spy areas from above without the noise of the engine alerting those on the ground. As it is a glider it can stay in the air during long periods of time saving battery and avoiding noise alert.

Wikipedia: “First-person view (FPV) flight is a type of remote-control flying that has grown in popularity in recent years. It involves mounting a small video camera and television transmitter on an RC aircraft and flying by means of a live video down-link, commonly displayed on video goggles or a portable LCD screen. When flying FPV, the pilot sees from the aircraft's perspective, and does not even have to look at the model. As a result, FPV aircraft can be flown well beyond visual range, limited only by the range of the remote control and video transmitter. Video transmitters typically operate at a power level between 200 mW and 1500 mW. The most common frequencies used for video transmission are 900 MHz, 1.2 GHz, 2.4 GHz, and 5.8 GHz.^[6] Specialized long-range UHF control systems operating at 433 MHz (for amateur radio licensees only) or 869 MHz^[6] are commonly used to achieve greater control range, while the use of directional, high-gain antennas increases video range. Sophisticated setups are capable of achieving a range of 20–30 miles or more.^[7] FPV aircraft are frequently used for aerial photography and videography, and many videos of FPV flights can be found on popular video sites such as YouTube and Vimeo.

A basic FPV system consists of a camera, video transmitter, video receiver, and a display. More advanced setups commonly add in specialized hardware, including on-screen displays with GPS navigation and flight data, stabilization systems, and autopilot devices with "return to home" capability—allowing the aircraft to fly back to its starting point on its own in the event of signal loss. On-board cameras can be equipped with a pan and tilt mount, which when coupled with video goggles and "head tracking" devices creates a truly immersive, first-person experience, as if the pilot was actually sitting in the cockpit of the RC aircraft.^[6]

Both helicopters and fixed-wing RC aircraft are used for FPV flight. The most commonly chosen airframes for FPV planes are larger models with sufficient payload space for the video equipment and large wings capable of supporting the extra weight. Pusher-propeller planes are preferred so that the propeller is not in view of the camera. Flying wing designs are also popular for FPV, as they provide a good combination of large wing surface area, speed, maneuverability, and gliding ability”.

State range.

State materials.

First things first

This is a project of study, design and manufacturing of a radio controlled airplane, whose main characteristics are a high aerodynamic efficiency (that of a glider, with no larger wingspan than 3 meters) and an on-board camera with a transmitter for live broadcasting to the pilot on the ground (also called FPV, first-person view flight).
Due to the iterations made while studying the plane configuration, it may end up being a drone Predator; only time will tell.

The project starts with the definition of phases, the first one (already completed) consists of searching for information that may concern every aspect related to this idea of plane and its systems.
This will lead to the most important part, choosing the specifications and objectives of the plane, its components and the proper configuration.

Each week the blog will be updated with the news about the progress.