The Contact Patch

Book : The Contact Patch https://the-contact-patch.com/book/general/g2020-welcome

very very nice:

Drag, Lift, Directional Stability

Book : The Contact Patch https://the-contact-patch.com/book/fluids/f1816-drag-lift-amp-directional-stability

 

"Chris Wright: Chris is Emeritus Professor of Transport Management, Middlesex University, London. Originally trained as a civil engineer, for the last 50 years he has specialised in transport research, serving at various times as chairman of the Executive Committee of the (UK) Universities Transport Study Group, and as a member of several professional committees including the editorial board of the Municipal Engineer. He has advised the London Assembly on aspects of the Mayor’s transport policy"

Thank you very much

 

the Owl and the Cat ... went to Sea

(I'm not entirely sure but i think the author is Chris's wife, maybe)

 

Production

Web realisation by Tom Wright: Tom is a developer and occasional photographer with nearly two decades under his belt building experiences for the web, helping people from small independent local businesses all the way up to FTSE100 companies find their place on the internet.

Layout by James Wright: James is a Graphic Designer and Art Director whose clients have ranged from blue chip corporations to boutique start-ups in fields as diverse as art, music, finance, and consumer goods.

Diagrams and text by Chris Wright: Chris is Emeritus Professor of Transport Management, Middlesex University, London.

Photographic images by Susanna Rosti Rossini: Susanna is a professional artist photographer and lives in Florence. She has studied interior architecture specialising in lighting design, and is passionate about jazz piano.

Painting of ‘The Owl and the Pussycat’ by Penny Wright: Penny has a BA in Graphic Fine Art from KIAD, and works as a print-maker and multi-media artist. She makes artist’s books and illustrates for children of all ages.


(maybe / perhaps

In British English both of these adverbs are still very commonly used and have the same meaning. You use them to say that something is possible or may be true, but you are not certain):

Quizás

 

(Hörner, Fluid Dynamic Lift)

With an Angle of Attack of zero the Lift Coefficient is 0.3 (!)

Although the Coefficient is striking, in the end it is a very small Force in relation to the weight of the vehicle

But the Lift created by the shape of the roof is funny

 

(OMEGA, Thomas Harrison Butler)

The magnificent performance of a well-made Classic is due to the sum of

1) Longitudinal Balance: LCB does not move aft when the yacht heels

2) Bow tolerant with Pitch because it does not create a vertical leading edge, and because the side is inclined and because it is joined in one piece/wing with the keel

3) Keel that forms a Delta Wing, the Center of Pressure moves aft as Yaw/Leeway increases, so for example with only StaySail it sails balanced, and if the Main is hoisted it also sails balanced because Leeway increases and then the lateral pressure of the water moves aft

And if the yacht yaws surfing down a big wave the same: the lateral hydrodynamic pressure of the water moves aft

So it is docile and very well behaved and tends to sail alone and does not require much rudder force/action

4) and finally: the vertical component of the hydrodynamic pressures:

High pressure at bow and Low pressure, Suction, in stern that, Bow Up, Stern down, transform the yacht into a prodigious Surfboard

 

(Hörner, Fluid Dynamic Lift)

 

Tested fully submerged in a towing Tank

The lateral hydrodynamic force that a modern bow can produce is not only frighteningly enormous, but its Center of Pressure has an enormous lever arm since it is located almost right next to the leading edge.

 

The bad character of many modern yachts is due to

1) the mismatch between LCB and LCF and specifically LCF aft of LCB (instead of in the same position or forward): LCF aft of LCB on the one hand causes a bow-down pitch when heeling, and on the other hand makes it easier for the wave coming from the stern to cause a faster and deeper pitch

2) the bow capable of creating a lot of lateral force with a center of pressure very far forward

3) the hydrodynamic center of the keel forward of the yacht Center of Gravity, and

4) all its imbalances feed back and reinforce each other in a lot of loops

---

LCB: Longitudinal position of Center of Buoyancy

LCF: Longitudinal position of Center of Flotation

LCG: Longitudinal position of Center of Gravity

 

We must go back to the past (?)

It is not necessary. We can study and understand the classical solution and recreate the high peak of the classics by modern means

 

T. Harrison Butler in Memoriam

In gratitude for your light and your careful care on this dark and gloomy planet earth

 

Haha

Alfred Turner, using models, figure out what was the best Delta Wing to control Yaw

Alfred Turner Delta Wing that we see in Thomas Harrison Butler's designs

The funny thing is that this Delta Wing shape has just reappeared in the incredible Chinese air superiority aircraft shown to the public on December 26th of last year, which was just a few days ago

---

Engineer Rear-Admiral Alfred Turner, "A Law of Hydrostatics and its Influence on the Shapes of Sailing Yachts", a paper read at the spring meeting of the Institution of Naval Architects, March 1937

 

The trailing edge of the Chinese air superiority aircraft's Delta Wing has 10 control surfaces plus 3 engines

Thomas Harrison Butler's OMEGA on the trailing edge of the Delta Wing has only 1 control surface: the rudder

 

And the Control ...

 

Alfred Turner empirically proved that for Control it was better if the trailing edge of the delta wing was tilted

look at the profile of OMEGA with the tilted trailing edge above in this thread

I have always been intrigued by this inclination of the rudder of these British Classics

I know, like Turner and Butler, that it works; but honestly, despite having studied it, I don't understand it