How can aircraft like the Panther, Sonex and Lightening meet LSA requirements? Aren’t they too fast?


We consistently get questions on how the Panther can meet the LSA top speed requirements. This is the most miss-understood part of the LSA rule. The rule states the aircraft cannot:


1.Exceed 120 knots at sea level

a.  On standard day conditions

b.  At max continuous power.


On LSA aircraft like the Panther, Sonex and Lightening the combination of propellers and engines have set limits to comply with these requirements. Using the Panther with a 3.0L Corvair engine and a 62” prop we set the maximum continuous RPM to 2650. This keeps us at 120 knots and gives excellent fuel consumption (about 4 gallons per hour). The engine and prop combo is capable of turning more RPM than 2650 (about 3200 for the Corvair 3.0L). This allows excellent take off and climb performance using all available power and RPM, while still meeting the requirements for 120 knots continuous power at sea level.


In the case of the Corvair the builder is the manufacturer of the engine and sets all limits. Furthermore, any engine powering an EAB aircraft is not certified (even if it used to be like a Lycoming or Continental) and the builder has the responsibility of testing and setting the limits.


The other LSA guidelines and how the Panther meets them:



Panther LS with Corvair 3.0L

Gross Weight = 1320 or less

1115 lbs gross weight

Stall Speed = 51.5 mph or less

51 mph clean

Maximum speed in level flight with maximum continuous power (Vh) of not more than 120 kts (138 mph) CAS under standard atmospheric conditions at sea level.

Max continuous RPM on the Panther Corvair 3.0L installation with 62” prop is 2650 RPM. This yields 138 MPH CAS at sea level

Unpowered or Single Engine Powered

Panther is single engine


Panther is not pressurized

Two Occupants or Less

Panther is a single seat aircraft


The Panther is a versatile and affordable aircraft that has excellent performance, with capacities and payloads for larger pilots, while maintaining the simplicity and safety of the LSA regulations.

The combination of the propeller and the Corvair will have a max continuous power rating which will keep the Panther below 138 mph at sea level on a standard day.