# Aerodynamicists:  What is the advantage of negative dihedral on the Harrier?

**URL:** <https://boards.straightdope.com/t/aerodynamicists-what-is-the-advantage-of-negative-dihedral-on-the-harrier/252243>\
**Category:** Factual Questions\
**Created:** [June 25, 2004, 9:50pm UTC](https://boards.straightdope.com/t/aerodynamicists-what-is-the-advantage-of-negative-dihedral-on-the-harrier/252243 "2004-06-25T21:50:50Z")\
**Posts on this page:** 3\
**Page:** 2

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**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\
**Post date:** [June 26, 2004, 5:01am UTC](https://boards.straightdope.com/t/aerodynamicists-what-is-the-advantage-of-negative-dihedral-on-the-harrier/252243/21 "2004-06-26T05:01:38Z")

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On further thinking about my vector diagram in a previous post it is just barely possible that I could be mistaken about the cause of the overbanking tendency.

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**Author:** ![Bippy\_the\_Beardless](https://avatars.discourse-cdn.com/v4/letter/b/ac8455/32.png) [@Bippy\_the\_Beardless](https://boards.straightdope.com/u/Bippy_the_Beardless)\
**Post date:** [June 28, 2004, 9:43pm UTC](https://boards.straightdope.com/t/aerodynamicists-what-is-the-advantage-of-negative-dihedral-on-the-harrier/252243/22 "2004-06-28T21:43:55Z")

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> [@David Simmons](#):
>
> This might come as a shock but we had computers in the 1960’s. A special purpose computer, otherwise known as an autopilot, to provide stability could have been in the Harrier from its beginning.

I did know about computers existing in the 60’s (and the 1940’s) but I didn’t think they were up to the task of real time aircraft stabilization for an inherantly unstable aircraft.  
Oh, and here is a great site for Harrier details [http://www.harrier.org.uk/history/index.htm](http://www.harrier.org.uk/history/index.htm)

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**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\
**Post date:** [June 28, 2004, 11:59pm UTC](https://boards.straightdope.com/t/aerodynamicists-what-is-the-advantage-of-negative-dihedral-on-the-harrier/252243/23 "2004-06-28T23:59:55Z")

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> [@Bippy the Beardless](#):
>
> I did know about computers existing in the 60’s (and the 1940’s) but I didn’t think they were up to the task of real time aircraft stabilization for an inherantly unstable aircraft.  
> Oh, and here is a great site for Harrier details [http://www.harrier.org.uk/history/index.htm](http://www.harrier.org.uk/history/index.htm)

I’m not sure that a 1960’s digital computer _would_ have been fast enough. But analog computers, which are now pretty much a thing of the past, worked in real time. For example you could have a three axis rate gyro, use those outputs as the control inputs and take it from there.

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