REFLECTOR: Vne (was 'interesting read')

[Scott Baker]

Danny Maher has often said that the Velocity wing is a "200 Knot" wing - meaning the lift/drag of the wing begin to loose efficiency at 200knots (indicated).  The Velocity standard fixed gear (the original Velocity) featured a Lycoming 200hp engine - which resulted in a normal cruise speed somewhere between 160 to 165 knots.  When Dan and company hired a professional test pilot for the flight-tests, they reckoned that 200 knots (indicated) was a good limit due because this number represented a good safety factor beyond what the aircraft was able to deliver during cruise.
Today we have retract gear and engines with higher power - which can push the aircraft to 200knots indicated during level flight, given the right outside air temperature, altitude, power and propeller.  RG aircraft can easily push through 200KIAS during an expedited descent.
Velocity, Inc. has been following the conservative road by recommending a Vne of 200KIAS because the aircraft has not been professionally flight tested beyond this limit.  Velocity owners have reported many stories of flying 210, 220, 230KIAS (675-hp Lycoming turbine owned by Mike Hillyer) - and several more "There I was ..." stories that go beyond 230 knots (air speed indicator was 'pegged') - all without structural damage or flutter.
Velocity and the Rocket Racing League will be operating Velocity SE aircraft at speeds greater than 200KIAS.  I am sure there will be reports to these developments for all to see.
Best regards,
SB

  ----- Original Message ----- 
  From: Chuck Jensen 
  To: Velocity Aircraft Owners and Builders list 
  Sent: Sunday, December 11, 2005 1:12 PM
  Subject: RE: REFLECTOR: Vne (was 'interesting read')


  Al,

  As the article discussed, if your IAS was 210 at 10K, your TAS, which is what counts, was likely much higher, depending on temp.  Scott B. said in an earlier post that the 200kts Vne for the Velocity was based on flight testing by a test pilot.  I'm not sure how that works?  Was some flutter encountered above 200kts, or was it just tested to 200kts TAS and no flutter could be induced despite wacks and other upsets?  If that's the case, then that doesn't say anything about 201, 220, 250 or 300?

   

  Structurally, it would seem that the Velo has it all over the RV given their respective +/-G ratings.  Flutter, though is markedly different.  I've not heard remarked of an incidence of flutter in the ailerons in a Velo, though if the toe-in of the winglets is reduced too far, the rudders will 'flap in the wind', as a couple have reported.  Maybe Scott will weigh in with additional info.

   

  Chuck Jensen

   
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