zfennell wrote:
...
Bille has a point about the potential drag penality, but i believe the cost will be mostly a function of the total surface area for the strut that you choose. ( a quick check in Abbott's book for airfoils will give you relative drag numbers to play with)
...
-bill
Ironic -- that now I'm the one pushing the Wood for my first foil .
On the Drag thing due to thickness :
Two equally thick airfoil profiles that have the thickness distribution at the same
cord percentage, but with different cord Lengths ; the Longer cord length
will produce LESS drag , even though it has MORE surface aria.
Example here , and pretend both high-points are at 35% back from the Leading Edge :
1) cord thickness = 15mm, cord length = 120mm -------------- 12.5% cord-thickness.
2) cord thickness = 15mm, cord length = 100mm ------------ 15%% cord thickness.
# 1 will be FASTER, even though it has MORE surface aria !!!!
The percent thickness of an airfoil is one of the Most important factors
regarding the ultimate speed the airfoil will be allowed to go. As a beginner
on a foil-board, i kinda could care less though ; i just don't wanna be able
to break it.
don pitcher wrote:
...
Billie,
If using aluminum extrusions, an aluminum hydrofoil can be about the same weight as a Carafino. Also, the concern about aluminum not being safe is not true. The ski boat world has been using aluminum hydrofoils for years.
...
Most foil-chairs that are towed behind a boat ; yes -- your strapped-in, so
there's little chance you'll be hit in the head when you fall.
On the Safety part ; who should i believe More :
* You, that has never made a decent foil-board in his life, and who's work
looks like a 3rd grader built it .
OR
** Carafino , who has made and sold more hydrofoils in his life, than most
any person on the planet .
I'll go with Carafino Thank-you !!
Plenty of HG pilots with aluminum down-tubes, have had broken arms
over the years, (including me) ; the guys that use the carbon ones say
that the carbon down-tubes break before the arm does, so there Safer in that respect.
C A R A F I N O 2014 wrote:
Metal kills people, no matter how light you can make it. No matter how fast it will go. Metal is out.
Plus the cost for titanium is horrendous. keep up the good work.
Bille