OSD for the Flying Wing.

(This includes the Mechanical and Electrical construction of needed equipment)

The flying wing will be able to transmit the following information via the video signal:

Battery voltage.

Temperature of motor.

Altitude.

Speed.

Current Vertical G-force.

Current Horizontal G-force (Acceleration).

Speed measurement:

The measurement of the speed will be done by building a primitive type of PITOT tube. This construction will be able to measure the Model airplanes speed in the air.

Normally a PITOT tube is constructed by the following design:

The speed of the airflow can be calculated with following formula:

v = speed of airflow [m/s]
P-tot = total pressure [Pa]
P-stat = static pressure [Pa]
r = density of the gas measured [kg/m3]

Instead of making a fancy PITOT tube like the above description, it is much simpler (for us mortals) to split the design apart, and have one tube for measuring the Static pressure, and one for the Total pressure.

Construction of the Static pressure tube and the Pressure tube to measure the total front pressure.

You can clearly se the small holes in the Static pressure tube. (Its important not to make groves at the edges on the holes, and keep them at absolutely 90 degrees angles, otherwise the airspeed reading will be false, wince the holes will build a under pressure or over pressure in the static tube - giving false reading)

The total pressure tube has a increased opening area, to increase the dynamic range of the probe, giving it more accuracy We are not going to have the greatest speeds on a flying wing !!

The pressure sensor for the project are Motorola's MPX5010 that measures differential pressure directly from the 2 probes. Another Motorola sensor MPX4115 will be inserted in the pressure way of the Static tube, and will be used as Altitude measurer.

TO BE CONTINUED

G - Force measurement:

The G-force measurement was first thought to be a hard nut to break, but it turns out that Analog Devices makes G force chips that is smaller the a SOIC8 package !!! And does the miracle in 2 axis. The chip ADXL202 can measure up to 2 G in 2 axis, perfect for Acceleration and downwards G measurement.

(I have placed an order for the ADXL210, witch can measure up to 10 G - Not that I will ever need it in a flying wing!!!)

You provide 2 external capacitors and one resister and a supply of 5 volts, and it will supply you with a Square pulse witch length is directly proportional to the devices G-force (An analog signal can also be taken from the chip). - I guess it doesn't come better than this (it actually does - They are happy to ship the chips as samples (-:  ).

TO BE CONTINUED

Email me at -

Email me at - kimfmx@gmail.com