Good point Svein=0AGraham=0A=0A=0A=0A=0A________________________________=0A
From: Sidsel & Svein Johnsen <sidsel.svein@oslo.online.no>=0ATo: europa-li
st@matronics.com =0ASent: Monday, 1 July 2013, 15:21=0ASubject: SV: Europa-
List: Re: wing lift/drag pins=0A =0A=0A=0AThis has been an interesting disc
ussion, but it appears to me that it got off-track somewhere because "forwa
rd" has two meanings (see the attached illustrations):=0A=C2-=0A(i)=C2-
=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2
-=C2-=C2-=C2- The LIFT does not have a =9Cforward=9D co
mponent, under any circumstances, if FORWARD means the direction of the air
craft=99s flight.=C2- Reason:=C2- LIFT is by definition always pe
rpendicular to the direction of flight, as DRAG is always opposite to the d
irection of flight (i.e. perpendicular to the LIFT).=0A=C2-=0A(ii)=C2-
=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2
-=C2- If, however, one refers to FORWARD as the direction of the aircra
fts centerline, then LIFT has a =9Cforward=9D component as soon
as the centerline points up at the nose relative to the direction of fligh
t.=C2- The higher the nose points up, the greater this forward component
is.=C2- At some point it may, as I read the discussion, become larger tha
n the wing DRAG=99s component parallel to the centerline in the oppos
ite direction, giving a net =9Cforward=9D force on the wing.=0A
=C2-=0A(iii)=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-
=C2-=C2-=C2-=C2- The LIFT does not contribute, under any circumstan
ces, to moving the aircraft forward through the air, as there is no lift co
mponent parallel to the direction of flight.=C2- A glider is =9Cpro
pelled=9D by the forward =93 in the direction of flight
=93 component of the aircraft=99s WEIGHT only.=0A=C2-=0A=C2-=0ARe
gards,=0ASvein=0ALN-SKJ
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