The ASI-4 for Experimental / LSA aircraft is a 2 1/4” sunlight readable instrument that provides a wide range airspeed indication in both digital and analog tape formats. Airspeed is based on the pressure generated by a pitot tube system and a static port is provided as well for use in high speed aircraft. In addition, the ASI-4 provides a flight timer since takeoff and records the maximum airspeed reached.
Airspeed can be indicated in statute miles per hour (mph), kilometers per hour (km/h) or knots (kts). The analog airspeed tape can be scaled according to the aircraft’s flying speed range and ranges for Vs0, Vs1, Vfe, Vno and Vne can be set. The ASI-4 also provides a programmable Vs and Vne airspeed alarm output. ASI sensitivity can be calibrated by the user to cater for errors caused by pitot tube placement.
The ASI-4 instrument measures airspeed from 16mph to 250mph and is well suited to slower aircraft due to very good sensitivity and linearity at low air speeds.
The unit seemed at first to be a little pricey but I wanted a digital readout on a 2 1/4 unit. Am very pleased with the readability of the screen and the accuracy as gauged by mimicking the airspeeds seen on the analog ASI. Highly recommend the unit and the service supplied by Aircraft Spruce.