REFLECTOR: speed

[Al Gietzen]

Lou;

 

I’d expect it is a combination of factors.  Given your takeoff roll vs WOT
speed it does sound like a drag issue; but also seems like a power issue.
But 180 hp on a fixed gear Velocity is somewhat under powered.  Good wheel
pants could certainly help. Higher engine rpm equals more power; so a
reduction in pitch is in order.  A Catto prop is good to 3000 rpm, and that
would be a significant power increase over 2550.  Direct drive aircraft
engines are operating significantly below peak power rpm. Reduced drag and
increased power is a place to start.

 

I think the incidence of the canard is also a factor. Having the elevator
trailing edge down is like flying with flaps extended.  I’m quite convinced
that on the canard airfoil, the drag is lower with the trailing edge up at
least ½”.  Yes, if you could generate more speed with different power/prop
combination, your trailing edge would come up a bit, but I’d guess not
enough.  I don’t find much difference in trim between 140 and 160 knots.  I
also find little difference in elevator position at cruise with CG near aft
limit, and CG near the middle of the box.  At 160 Kt cruise, my elevator is
trailing edge about 5/8” up.  It could be that my experience or others with
Wingco canards, is a bit different since we have a bit more camber on the
canard and 8” wider span.

 

Good luck,

 

Al

 

 

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Lou Stedman
Sent: Friday, May 01, 2009 7:31 PM
To: canard Aviators; Reflector Velocity
Subject: REFLECTOR: speed

 

I have been going over my VEL to try and pick up some more cruise speed. I
have cleaned up the cowl and I am putting on wheel pants. I have never been
happy with the performance of 44Q. I have a IO-360, 180 HP, with a Catto
three blade prop. My static is not what I would like, 2250 at takeoff power
and the best I can get a WOT is about 2550. At one time I flew with a two
blade Catto and got better static but lost it in cruise. I sent my prop back
to Catto and he removed some of the pitch but I have not seen much
difference. One thing I have noticed is that when I am flying solo and the
aircraft is trimmed for level flight, my elevator is down about 3/4". That
must be causing drag but I don't know what to do to correct. Any
suggestions?

 

Lou Stedman
Velocity N7044Q
Olean, NY

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