RE: [PSUBS-MAILIST] RE: airfoils

[Alec Smyth <Asmyth@changepoint.com>]

Yep, I remember being amazed at the handling of the towable contraption too.
I had expected some sort of slight inertia to affect maneuvers. Instead, if
you pointed up or down you were instantly on a new trajectory without any
discernible "slip" whatsoever. No matter how slow you were going, it felt as
if the airfoils were carving through a solid rather than through liquid.

Vance, I realize this thing was a pathetically lightweight little toy, even
compared to a PSUB. But the construction was a piece of cake. I just cut a
sheet of aluminum for the skin and bent it over the shaft by hand -- it came
out really even. Hey, the two airfoils even looked alike. Then I pop riveted
the trailing edges together, and put some more rivets into the shaft to keep
the airfoil in position. Sure, the rivets don't make for a super-clean
surface and it wasn't any standard NACA profile, but it worked great anyway.
This construction left the whole thing open at the ends, which wasn't really
a problem either. 

I think I've seen on Carsten's pictures that he intends filling his planes
with oil, which sounds much more elegant. 

-Alec 

-----Original Message-----
From: VBra676539@aol.com [mailto:VBra676539@aol.com]
Sent: Monday, March 05, 2001 6:23 PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] RE: airfoils


Alec and all,

As an addendum to this, Perry built hollow aluminum airfoil sections for
dive 
planes and rudders on the later subs. I trained initially on the old PC-8, 
which had flat slab control surfaces, and I can attest to how well the more 
sophisticated surfaces worked in comparison. The airfoil sections had flat 
plates welded to the sides to improve efficiency and were hydraulically 
activated.

If the sub was moving forward at neutral buoyancy, and you tipped the planes

up, the sub would lift. Period. No discussion. Up she comes. A couple of 
square feet of dive planes would lift an 8 ton 12-boat off the bottom with
no 
effort at all. Our rudders were the same, measured about 42" high by roughly

a foot front to back. We turned 36 X 36 bronze wheels through reduction
gears 
and when you swung the rudder over, she turned, and I mean right now.

The earlier boats used plexiglas plate for planes and a composite flat 
material for the rudders. They worked okay, but not nearly as well as the 
airfoil shapes, which were a pain to build and horrible expensive, but
really 
worth their weight in hot dogs when push came to shove. I'm planning on 
planes and rudder for my K this summer, so I'm going to have to figure this 
out for real. I sure wish I'd kept some of those prints around from back 
then. Hopefully I can work something out in fiberglas which will then become

a market sensation in the psubs biz and make me jillions.

Vance