UK-Cherub Forum

Cherub Chat => Tech Chat => Topic started by: Will_Lee on January 19, 2009, 06:57:03 AM

Title: Lecture in London on Tuesday 20th jan
Post by: Will_Lee on January 19, 2009, 06:57:03 AM

I plan to go. Has quite a cherubby feel I think.

Title: Re: Lecture in London on Tuesday 20th jan
Post by: Tom K on January 19, 2009, 10:16:00 PM

Sadly I couldn't make it in time after work :( Make sure you take notes i can borrow!

Title: Re: Lecture in London on Tuesday 20th jan
Post by: roland_trim on January 20, 2009, 11:19:12 AM

How is the distance measured? I it first contact with the water or could a combination glider- foiler win it?

Title: Re: Lecture in London on Tuesday 20th jan
Post by: Will_Lee on January 21, 2009, 10:12:54 AM

http://www.birdman.org.uk/measuredistance.html

http://www.birdman.org.uk/index.html

Any part touches, and you have landed (or possibly 'watered')

The speaker described his own attempts to win this competition. The key fact presented is that the wingspan is limited to 9m, which makes making a good enough glider difficult. The ground effect is important, and this inspired the 2008 model which was a low-wing glider.

The key fact not presented is that this looks like a challenge for eggheads, when it is really a challenge for atheletes. It has been won in recent years by a hang-gliding instructor in an ordinary hang-glider who chops off the tips of the wings of his hang-glider to make it measure. This makes a planform  which will be undertapered, making for more induced drag, the very thing that it is critical to reduce in slow flight. However this counts for little against someone who has the skills and strength to get a good takeoff speed and turn from 'strong runner' to 'good pilot' instantly.

The videos make good viewing:

http://uk.youtube.com/watch?v=Kt5E9jQWfxY&feature=related