Arvel Gentry () was an aerodynamicist. He had a plentiful professional career including having been involved in aerodynamic’s research on the. The Origins of Lift – By Arvel Gentry (January ). July 24, at PM. [ Esta es una copia de una página web que ya no está disponible en la red. Some changes to the Goat Island Skiff sail and how to use leach ribbons or tufts for more accurate sail trimming and steering to reach greater sailing efficiency.

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I have recieved via PM an apology from the also apparently original Ian D.

Thejib helps the mainsail by reducing the peak suction pressure nearthe mast so the sail will not stall. The speed of the flow increases in areas where thestreamlines get closer together such as near the leading edge ofthe airfoil. In the Revised Edition, the authors used computer testing to show where the wind speeds up around a sail plan and where it slows down. The boats in the pics look a little old and funky but the wind hasn’t changed a bit since those days.

BTW, how did you manage to find a ‘newspaper article’ that old? So in my elementary sailing texts, the AOA on the sail wind direction relative to chord of sail is drawn at 60 degrees or so.

Trying to prove that linear flow alone produces lift has confused sailors for decades. How do sails really create thrust? On an infinitely long wing, the 3-D effects are gone and we areessentially back to looking at two-dimensional airfoilaerodynamics.


A quantum liquid may be pushing the definition of a “real fluid” a bit, but I have thought that this experiment might help illustrate the fact that a fluid’s friction properties are responsible for the generation of lift.

This means that theflow on the jib is improved by the presence of the mainsail.

If youride a bicycle in a crosswind, you feel only one wind on yourface, the vector combination of the true wind plus a wind vectorrepresenting the speed of the bicycle. A flat plateairfoil is used here to illustrate this.

Again, I thank you all for your input at this difficult time. The flow field around an airfoil is the combination oftwo flow fields: With two sails, arvvel airfoil has its owncirculation flow field. To understand the fundamentals of how lift isgenerated, it is best to start with a simple two-dimensional airfoil.

Itwas interesting that the introduction in this book was by noneother than the same Russell J. Non-lifting flow around a flat plate. It is a bad place to expect anything other than bad wrvel.

Arvel Gentry Archives – Really Simple Sails

Again, the green streamlines are thestagnation streamlines and divide the flow that goes on top leeside from the flow on the lower windward side. Gentry changed forever the real understanding about the theory and application of the mechanics of how foils work, by explaining arveo in simple layman terms that even Aevel could understand.

This is a dynamicprocess that becomes stable when the starting vortex is sweptdownstream and the flow conditions at the trailing edge havebecome smooth and stable. I expected some words of comdolence for Kim in this hard moments, but certainly this is not the right place for that. Selling something that is free, what a bad business!.


Krishnamurty Karamcheti, Principles of Ideal-fluidAerodynamics. That paper alsomade it clear that the old theories as to how slats and slots on theleading edge of aircraft wings worked were also wrong.

Arvel Gentry

Water channel photograph showing separated flow. This is not the whole story. He was also a successful ocean racing skipper and an amateur photographer. This experiment can be done with a conventional thickairfoil to illustrate the starting vortex and the upwash flow.

He was a wonderfully insightful scientist, and a much loved and respected mentor. In the case of objects with blunttrailing edges, the resulting separated flow region may bethought of as a rough extension of the original airfoil, and astarting vortex will be formed and circulation developed. I’ll send you a private message for us to keep in contact.

Arvel Gentry’s site | Boat Design Net

Kim, I am so sorry to hear such sad news. And on the “deflecting the air downward” idea, that is athree-dimensional effect.

Judy Blumhorst Judy Hydesailsdirect.