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Altitude measurement (except boat), Installing temperature sensor(s) – Eagle Tree Pro, Glide, Flight and Boat Seagull Wireless Telemetry and Data Recorder User Manual

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Copyright © 2003-2010 Eagle Tree Systems, LLC

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Follow these guidelines when mounting the pitot tube:
Flight Pitot Tube Installations

1.

The pickup end of the pitot tube (the silver colored tip) should be pointing toward the direction of the model’s travel.
While best results will be obtained if the pitot tube is perfectly aligned with the direction of travel in both axes, the
“Prandtl” design of the tube will compensate somewhat for higher angles of attack.


2.

The static holes on the pitot tube (shown on Figure 1) should extend at least 1/2” (13mm) past the wing’s leading
edge, or past any other obstructions - the farther out, the better. This is to ensure that the static holes and pitot
pickup are in undisturbed air.


3.

For prop planes, it’s important that the tube be placed so that it is not directly in the plane’s prop-wash, which will
result in erroneous readings. The best place to install the tube is on the leading edge of the wing several inches out
from the fuselage, as shown in Figure 1.


4.

For jets, gliders, or “pusher” prop planes, the nose cone often provides a perfect mounting location.


5.

After Pitot Tube installation, it is recommended that you glue or otherwise attach the silicon hose to the airframe, to
reduce the chance that hose vibration or movement could cause erroneous readings.


Boat Pitot Tube Installations

If you have the standard Airspeed option for boat speed measurement, the pitot should be rigidly mounted somewhere on
the boat where the mouth of the tube will be pointing toward the direction of the boat’s travel, as far away from water
spray as possible. The tube needs to be in smooth air out of the air pocket that surrounds the surface of the boat. The
tube should point at right angles with the plane of travel, which may mean that the tube points slightly downward when
the boat is not planing due to upward tilt of the bow during planing.

If you ordered the Waterspeed option for boat speed measurement (ok for up to about 50 MPH), the included brass tube
should be rigidly mounted on your boat’s transom, so that the end of the brass tube is in the water, and bent so that the
tube’s mouth is pointing toward the direction of travel. The tube should be far enough below the bottom of the boat so
that it maintains contact with the water even when the boat is planing. Connect the brass tube to the silicon tubing
supplied. WARNING: if using the Waterspeed option, it is recommended that you either glue or otherwise
reinforce (with a zip tie, spring clip, or other) the silicon tube to the recorder’s speed nipple. This is because, if the
tube detached from the nipple during the run, the boat could be flooded by water coming through the tube! The
recorder’s case lid can be removed to access the nipple as needed for reinforcing.

Altitude Measurement (except Boat)


The Seagull Pro system measures altitude via a sensor inside the unit. Altimeters measure slight pressure differences to
determine elevation. Since these pressure differences are relatively small, it’s important that the model’s internal
pressure doesn’t vary much due to propwash or moving through the air. Such variation can occur if the front portion of
the model has an opening that causes air to compress inside of the model when air is forced into this opening. If there is
variation inside the fuselage, connect the altitude port to the static source via the T fitting, as shown in Figure 1. Here are
the steps:

1.

If you have a Pro recorder, skip to step 4

2.

If you have a non-Pro recorder, remove the Recorder’s case top.

3.

There is a predrilled hole to accommodate an external altitude tube. Look at the back of your recorder cover, and use
an x-acto knife to carefully cut the label around the hole.

4.

Connect silicon tube to the nipple of the altimeter sensor just like you do the pitot tube for airspeed, using the included
‘T’ fitting, as shown in Figure 1.

Installing Temperature Sensor(s)