REFLECTOR: Thrustline change

Fri Mar 29 17:00:20 CDT 2013

Steve,

The standard aircraft elevator and horizontal stab use a downward force to raise the nose and that is drag. The canard uses an upward force to lift the nose which much less drag. 

With the canard elevator raised slightly you are removing some of the lift from the canard by changing the cord line and lowering at the same time the amount of drag. 

I am currently (only in primer and no laminar flow whatsoever) flying with my ailerons reflexed up 1/8" and my canard elevator sits just slightly above the centerline of the canard so I keep it reflexed too. 

Right now I am rotating around 80kts and airborne between 85-90kts in my IO-390-X MT SERG. 

Richard

Sent from my iPhone 5

On Mar 29, 2013, at 5:20 PM, steve korney <s_korney at hotmail.com> wrote:

> 
> Richard...
> 
> I have a question...
> 
> In general...........Does it take more energy to keep the nose of a canard aircraft down with elevator trim, or to keep the nose of a conventional aircraft down with elevator trim...? 
> 
> 
> Steve 
> 
> > From: richard at naples-air-center.com
> > Date: Fri, 29 Mar 2013 16:29:04 -0400
> > To: reflector at tvbf.org
> > Subject: Re: REFLECTOR: Thrustline change
> > 
> > David,
> > 
> > Think of it as reflexing your Canard. That is very efficient since you are removing lift and drag from the control surface. 
> > 
> > Richard
> > 
> > Sent from my iPhone 5
> > 
> > On Mar 29, 2013, at 1:29 PM, "David Ullman" <ullman at robustdecisions.com> wrote:
> > 
> > > When I cruise with only me in the SEFG I have to put in 1/2 inch of down
> > > trim (elevator up) or more. This is clearly inefficient. I already have
> > > 18lb of lead in the nose and don't want to add more. A friend suggested
> > > shimming the top of the engine mount for a little downward pitch moment. I
> > > sort of like the idea but am worried that it might increase my take off
> > > distance as it will drive the canard downward a little. He thinks it may
> > > help as the engine thrust line is slight more upward. 
> > > 
> > > Any thoughts or experiences?
> > > 
> > > 
> > > David Ullman
> > > N444DX
> > > President EAA 292
> > > 541-760-2338
> > > david at davidullman.com
> > > 
> > > 
> > > 
> > > 
> > > 
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