Re: stab dihedral, fins, etc...

From: soslipstream <parkreation_at_msn.com>
Date: Mon, 26 Feb 2007 19:52:58 -0000

Hey Marty,

My 2 cents (sense?):

I have had the same questions and notables have given various
responses. Walt Eggert was good at his craft.......

1) The tip dihedral vs single rudder. Walt Eggert felt that anytime
the rudder was out of the turbulence of the prop, the more effective
it became. Single rudders, as he (note: Walt was an engineer most of
his life and earlier, he fixed P-38s in the South Pacific- WWII)
thought, were only about 1/3 effective when mounted behind the prop.
Tip dihedral was a small step away from this scenario but small twin
fins was best. At least as long as there wasn't a penalty for
weight/mass. Besides, twin fins added a bit style if not a little
intimidation and panache'to the airplanes presence.

2) Walt was a contemporary of Jim Grant and knew him well. He, too,
spent a couple of years working V-tails into his EZB and Unlimited
Pennyplanes. Eventually it seemed the trimming complexities and P-
factor mysteries was the reason to retire the concept. Obviously mass
can be saved with a V-tail but control headaches seem to abound.

Hope this helps,
Tom Sanders
  


--- In Indoor_Construction_at_yahoogroups.com, Marty Sasaki <marty@...>
wrote:
>
> I've used both tip dihedral on stabs and separate rudder, but have
> always wondered why one would choose one configuration over the
other?
> I've been looking for an A6 design and several plans that I've seen
> have a bit of V-dihedral in the stab even with a separate
> rudder. What's the thinking behind this?
>
> And one final question, yes, I know I have asked quite a few
> questions...
>
> With the passing of Jim Grant, I haven't seen any models that use a
> V-tail. What are the advantages and disadvantages with using a V-
tail?
>
> I think I'll make a V-tail A6 and add some red color to the frame
and
> covering in honor of Jim Grant...
>
> Marty Sasaki
>
Received on Mon Feb 26 2007 - 11:53:26 CET