lml@lancaironline.net Mailing List Archive

Winglets help when flying with higher Angle of Attack, like take off & landing and very high altitude flight. When flying fast with much lower AoA, winglets hinder performance.

Wolfgang

From:	Colyn Case <colyncase@earthlink.net>
Sender:	<marv@lancaironline.net>
Subject:	Re: [LML] LNC4 WINGLETS
Date:	Wed, 09 Mar 2011 08:26:26 -0500
To:	lml@lancaironline.net

Hi Carl,

The short story is winglets don't help speed or efficiency in the regime's IV's generally fly.

They do add wetted area.

See Fred Moreno's write up here which says why they slow you down:

http://www.lancair.net/archives/Drag_Reduction_Part_1.pdf

Look for a post in the archives by Charlie Kohler which gives with/without numbers. Basically you'll lose 10 knots at low altitude and if memory serves, 4 knots indicated up high.

You can also find a post, I think, by Joe Bartels talking about how much nicer the roll response is without winglets.

Stall speeds are lower but I've never heard that stall characteristics are improved.

High altitude stability is reputed to be better but I haven't found anyone who has flown both to actually say that.

Colyn

On Mar 8, 2011, at 3:54 PM, Carl Scheid wrote:

I'm thinking of putting winglets on my IO 550 LIV. Can anyone help me with the performance change I might expect. I have heard that stall characteristics are improved?

Carl