Aviation From My Rocking Chair

Howdy again, Chapter 430 I am constantly amazed at all the things homebuilders must accomplish to finish their projects. Welding, gluing, fabric sewing, sanding, painting, riveting, instrument range marking. Oh…O.K., maybe range marking isn’t one of the major projects, but it is very important. Here is a review. I must warn you, There Will Be A Test!

(1) Airspeed Indicator.

a) White Arc- Flap operating range. Low end=Flaps down stall speed. Upper end= Max airspeed flaps down.

b) Green Arc- Normal operating range. Low end=Flaps up stall speed. Upper end=Max airspeed in rough air.

c) Yellow Arc- Structural warning area. Low end joins green arc and extends to Never Exceed Red Line. Permissible speed range in smooth air, but gusts could cause exceeded structural loads. (2) Tachometer a) Red radial line- Maximum permissible RPM.

b) Green Arc- Max. permissible RPM for continuous operation down to minimum recommended RPM for continuous operation except for restricted ranges.

c) Yellow Arc- Max. RPM for continuous operation up to Maximum RPM.

d) Red Arc- Range or ranges where operational speed is restricted, except to pass through. (3) Oil Temperature Indicator a) Red Radial Line- Max. or Min. permissible operating temperature.

b) Green Arc- Normal operating range.

c) Yellow Arc- Cautionary ranges indicating potential hazard due to overheating, etc. (4) Oil Pressure Indicator a) Red Radial Line- Max, or Min. permissible pressures as established by Engine Manufacturer. b) Green Arc- Normal Operation Range.

c) Yellow Arc- Cautionary Ranges indicating potential hazard due to low pressure at idle, over pressure during cold start, etc.

(5) Manifold Pressure Gauge a) Red Radial Line- Max. permissible Absolute Manifold Pressure for wet or dry operation (whichever is greater)

b) Green Arc- From Max. permissible pressure for continuous operation down to Min. pressure selected by Aircraft Manufacturer for cruise power.

c) Yellow Arc- From Max. pressure for continuous operation to Maximum permissible pressure.

Instrument Markings can make or break you.

And for all the Helicopter people out there (Me included), (1) Dual Tachometer a) Red Radial Line (engine)- Max. permissible RPM b) Red Radial Line (rotor)- Max. and Min. rotor RPM for power Off operations. c) Green Arc (engine)- From Max. RPM for continuous operation to Min. recommended RPM for continuous operation.

d) Green Arc (rotor)- Min. to Max normal operating range.

e) Yellow Arc- Engine precautionary ranges.

(2) Torque Indicator a) Red Radial Line- Max. permissible torque pressure for wet or dry operation (whichever is greater). b) Green Arc- From Max. torque pressure for continuous operation to Min. torque pressure recommended. c) Yellow Arc- From Max. torque pressure for continuous operation to Max. permissible torque pressure. Awww, forget the test. Just review your instrument markings, and be safe out there. Until next month, Rick Vaux TC 4130