[WWI] Anhedral vs Negative Dihedral (was Re: Added:Nieuport 28 andmore!) (UNCLASSIFIED)

[Andy Bannister]

I remember this coming up many years ago in a modelling magazine. Someone
(no doubt a modeller as we're always inventing new words!) decided that
"anhedral" is the opposite of "dihedral", however it was deemed incorrect at
the time and the dictionary backs this up:

di.he.dral 
1.	having or formed by two planes.
2.	of or pertaining to a dihedron.
3.	Aeronautics. the angle at which the right and left wings or the
halves of any other horizontal surface of an airplane or the like are
inclined upward or downward.

Anhedral produces only one reference in the definition of xenomorphic: 
xen.o.mor.phic
1.	Also, allotriomorphic. Petrography. noting or pertaining to a
mineral grain that does not have its characteristic crystalline form but has
a form impressed on it by surrounding grains; anhedral.
2.	in an unusual form; having a strange form.

Of course, other sources may differ!

Andy

> -----Original Message-----
> From: wwi-bounces at wwi-models.org 
> [mailto:wwi-bounces at wwi-models.org] On Behalf Of Acosta, 
> Kenneth J CTR MDA/DTC
> Sent: 01 August 2007 17:24
> To: wwi at wwi-models.org
> Subject: [WWI] Anhedral vs Negative Dihedral (was Re: 
> Added:Nieuport 28 andmore!) (UNCLASSIFIED)
> 
> 
> Classification:  UNCLASSIFIED 
> Caveats: NONE
> 
> De-lurking for a brief moment (my interest always piques 
> whenever aerodynamics is mentioned).
> 
> According to Ray Whitford in my handy copy of "Design for Air Combat":
> 
> "Viewed from the front, aircraft generally appear to have 
> their wings inclined upwards, with the tips being higher than 
> the roots (this is called dihedral), or downwards, with tips 
> lower than their roots (anhedral or negative dihedral)."
> 
> Looks like both are correct.  Give me a shout if you need to 
> know Whitford's credentials.
> 
> Re-lurking-
> Ken A.
> 
> 
> 
> Date: Wed, 1 Aug 2007 09:41:49 -0500
> From: "Tom Mason" <tom.mason at charter.net>
> Subject: Re: [WWI] Added:Nieuport 28 and more!
> To: "World War I Modeling Mailing List" <wwi at wwi-models.org>
> Message-ID: <00ba01c7d44a$1b780f70$b4960d47 at lssah>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> 	reply-type=original
> 
> Andy,
> 
> I am going by what I have read on aerodynamics. They all 
> state that the 
> opposite of dihedral is anhedral.
> 
> T.O.M.
> ----- Original Message ----- 
> From: "Andy Bannister" <a.bann at ntlworld.com>
> To: "World War I Modeling Mailing List" <wwi at wwi-models.org>
> Sent: Wednesday, August 01, 2007 6:57 AM
> Subject: Re: [WWI] Added:Nieuport 28 and more!
> 
> 
> > Actually, Scott's correct Tom. The word "dihedral" can be 
> negative or
> > positive. There is no such thing as anhedral in this context.
> According to 
> > my dictionary anyway.
> >
> > Andy
> >
> >>
> >> From: "Tom Mason" <tom.mason at charter.net>
> >> Date: 2007/08/01 Wed AM 04:25:24 GMT
> >> To: "World War I Modeling Mailing List" <wwi at wwi-models.org>
> >> Subject: Re: [WWI] Added:Nieuport 28 and more!
> >>
> >> Scott,
> >> Very nice Nieu. 28 & Sopwith Triplane.
> >> One small thing and not really a criticism. The term negative
> dihedral is
> >> incorrect. It should be called anhedral.
> >>
> >> T.O.M.
> Classification:  UNCLASSIFIED 
> Caveats: NONE
>