Bill,

Vne is specified by the manufacturer, including whether the measure is in TAS, CAS, IAS, etc.

For Vans, it is TRUE.

For Lancairs, it is IAS.

This is why VANS strongly discourages people from adding turbochargers, while they are somewhat common among Lancair builders.  A VANs aircraft with even an IO-390 may well be able to exceed Vne in level flight.

There has never been an incident of flutter (the most likely limiting factor for our planes when determining Vne) in a Lancair.  360's have been flown well over 300mph IAS racing.  Legacys and IVs have been flown much faster.

Lance and crew set Vne based on formulas and calculations with a margin of error.  If you stay within Vne you should never have a problem, and if you exceed it somewhat you MAY never have a problem.  But - it is not recommended if you value your safety.

Regards,

Bill Reister


Bill Kennedy wrote:

Van of Van's Aircraft wrote about VNE a couple of years ago. Much to my surprise, VNE is true airspeed, not indicated. It's pretty easy to exceed in my Lancair. Results can be explosive, meaning onset of flutter to component failure can be nearly instantaneous. I can't wear a parachute in my plane (Lancair 320), so I wouldn't screw around with it.