Re: martha jane's new rudder confusion
Hi Steve -
Leave the trailing edge square - if it turns out wrong, you can
always
taper it later.....
Mike
Leave the trailing edge square - if it turns out wrong, you can
always
taper it later.....
Mike
I confirm that the current opinion is that leading edges should be
parabolic and trailing edges shoud be sharp not rounded. It is not
important that the trailing edge be tapered to a feather.
Since that is the standard opinion and the words on the plans can be
construed to indicate that more easily than any other, I'd go with it.
Peter
parabolic and trailing edges shoud be sharp not rounded. It is not
important that the trailing edge be tapered to a feather.
Since that is the standard opinion and the words on the plans can be
construed to indicate that more easily than any other, I'd go with it.
Peter
I know that if you put a radius on the trailing edge, you will create
more drag. If the trailing edge is of finite thickness, it should end
sharply. Think of the back end of a sporty hatchback (one with
no spoiler.)Perhaps Bolger is worried that the typical convex taper
and rounding is going to be more drag than no taper! I have a hard
time visualising the bit about the parabola, but I bet you have a
drawing. I imagine he wants that 1/2 inch radius on the FRONT.
more drag. If the trailing edge is of finite thickness, it should end
sharply. Think of the back end of a sporty hatchback (one with
no spoiler.)Perhaps Bolger is worried that the typical convex taper
and rounding is going to be more drag than no taper! I have a hard
time visualising the bit about the parabola, but I bet you have a
drawing. I imagine he wants that 1/2 inch radius on the FRONT.
--- Inbolger@egroups.com, hwal@a... wrote:
snip
>
>snip The underwater trailing edge can be left square. snip The
underwater leading
edge should
> be faired and rounded off in a parabolic section ending in a
1/2-inch radius."
>
>snip I think he's saying
here
> that the parabolic section refers to the entire underwater portion
of the
> rudder - and that the leading edge is rounded off and the trailing
edge
> finally is planed down to a 1/2 inch radius (remember the entire
piece starts
> out 2" thick).
> snip
Here is a question - which I suspect none of you can answer - but I thought
I'd try. I'm wondering if it represents a typo. I'm working on the new
rudders for the revised Martha Jane - the rudder is a balanced rudder ( two
of them actually) and the construction notes describe the shaping of the
rudder thusly:
"Rudder blades built up to 2 inches thick, to the diagram at the top right of
sheet 2. The underwater trailing edge can be left square. The edge next to
the transom is rounded on a 1-inch radius. The underwater leading edge should
be faired and rounded off in a parabolic section ending in a 1/2-inch radius."
Maybe it's me - but the wording here seems confusing.
1) I wonder if "the underwater trailing edge can be left square" was meant
to read - the above water trailing edge can be left square.
and
2) "The underwater leading edge should be faired and rounded off in a
parabolic section ending in a 1/2-inch radius." I think he's saying here
that the parabolic section refers to the entire underwater portion of the
rudder - and that the leading edge is rounded off and the trailing edge
finally is planed down to a 1/2 inch radius (remember the entire piece starts
out 2" thick).
Do you see why I suspect an error in the text? Or am I missing something?
Steve Anderson ( Martha Jane Landroval)
I'd try. I'm wondering if it represents a typo. I'm working on the new
rudders for the revised Martha Jane - the rudder is a balanced rudder ( two
of them actually) and the construction notes describe the shaping of the
rudder thusly:
"Rudder blades built up to 2 inches thick, to the diagram at the top right of
sheet 2. The underwater trailing edge can be left square. The edge next to
the transom is rounded on a 1-inch radius. The underwater leading edge should
be faired and rounded off in a parabolic section ending in a 1/2-inch radius."
Maybe it's me - but the wording here seems confusing.
1) I wonder if "the underwater trailing edge can be left square" was meant
to read - the above water trailing edge can be left square.
and
2) "The underwater leading edge should be faired and rounded off in a
parabolic section ending in a 1/2-inch radius." I think he's saying here
that the parabolic section refers to the entire underwater portion of the
rudder - and that the leading edge is rounded off and the trailing edge
finally is planed down to a 1/2 inch radius (remember the entire piece starts
out 2" thick).
Do you see why I suspect an error in the text? Or am I missing something?
Steve Anderson ( Martha Jane Landroval)