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Door drag

Posted: Mon Jul 13, 2020 6:24 pm
by bomber
Here's the code

Code: Select all

            <function name="aero/coefficient/CDdoorL">
                <description>Drag_due_to_door_left</description>
                <product>
                    <property>aero/qbar-psf</property>
                    <property>metrics/Sw-sqft</property>
                    <property>/sim/model/door-positions/leftDoor/position-norm-effective</property>
                    <value>0.0300</value>
                </product>
            </function>


SO yet again we're using the wing area as a reference area.... looking at images I'd say the door opens to about 70degs which would be 0.94 of it's flat plate 90 degs area.

The difference in area of the door and wing is a ratio of 15.39....

So what we know is that the door at 90degs would offer a flat plate Cd of 1.28... at 70degs this would be 1.2.

So if we were to use the door area as the reference the above value of 0.03 would need to be 1.2/15.39 = 0.078 to give the equivalent drag

basically out by factor of 2.6

Simon

Re: Door drag

Posted: Mon Jul 13, 2020 8:24 pm
by Richard
bomber wrote:So if we were to use the door area as the reference the above value of 0.03 would need to be 1.2/15.39 = 0.078 to give the equivalent drag basically out by factor of 2.6


Raise an issue on their github.