REFLECTOR: High speed taxi tests

Bob Jackson (JaxTech) bobj at jaxtechllc.com
Sun Mar 6 10:31:51 CST 2011


I think that when the canard flies relative to the main wing is highly
dependent on aircraft (and nose) weight.  

 

Because our airplane is very heavy -- and the nose is proportionately also
very heavy (dual batteries, extra avionics, towbar adapter on the nosewheel,
etc) -- even at our lightest, the canard does not begin flying until ~85
kts.  With a co-pilot (we never need or use weight on the floor when there's
no co-pilot) onboard, we can't rotate below ~95 kts.  

 

In fact, because of the recent delamination on the top of one side of our
canard (now repaired - thanks for everyone's help here!), we are thinking
about building another canard (that would be at least a foot longer) to help
carry our extra nose/aircraft weight.  We want to lower our rotation, stall
and landing speeds.  Some of the super-heavy Velocity's being built and used
for UAVs by the military aerospace companies have increased the chord of the
canard as well as it's length.

 

Bob Jackson

N2XF

 

  _____  

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Scott Derrick
Sent: Sunday, March 06, 2011 7:50 AM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: High speed taxi tests

 

I know that this subject has come up in the past, however with new members 
joining the group - maybe it would be a good idea to highlight some 
important concerns relating to high-speed taxi testing of Velocity aircraft.
Everyone should know that in the aerodynamic design of the Velocity, the 
canard is designed to stall before the main wings.  This means, under most 
circumstances, that when the canard develops enough lift to rotate during 
take off, the main wings have been ready to fly for some time.

In my experience, when in ground effect, the reverse is true in that the
canard flies before the main wings.  The builder's manual seems to confirm
this.

"At 50 knots, the Velocity might rotate if full aft stick is applied, but
the aircraft will
not lift off."


I completely agree.   Because of ground effect,  main axle placement,
single pilot, etc..  I can always lift the nose before the main wings can
fly.

But when they do kick in it can be instantaneous and it would take some
experience to set back down in a comfortable and controlled fashion.

Scott



-- 
We are all here for a spell; get all the good laughs you can.
Will Rogers
  _____  


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