Today's Message Index:
----------------------
1. 08:57 AM - Re: Wing friction and speed... (Richard Mutzman)
2. 11:15 AM - Re: Re: Wing friction and speed... (Gary Vogt)
3. 12:55 PM - Re: Re: Wing friction and speed... (FLYaDIVE)
4. 02:27 PM - Re: wings and things (Richard Mutzman)
5. 07:51 PM - Re: Re: wings and things (Gary Vogt)
Message 1
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| Subject: | Re: Wing friction and speed... |
All:
The visousity of the fluid=2C the velocity of that fluid over the surface
=2C and the length of the surface (ie Reynolds Number) are a major players
here in how the boundry layer behaves. Before sanding or dimpling your win
gs=2C I would recommend you do some serious reading on boundary layer theor
y for compressible fluids.
PS- I know Roger's response is somewhat tongue and cheek we applied to air
plane wings.
Richard Mutzman
BSAE=2C MSAE
N399RM
Message: 5
From: Roger Rowlett <rrowlett@colgate.edu>
Subject: Wing friction and speed...
Content-Type: text/plain=3B charset="us-ascii"
OK=2C I was intrigued by the recent discussion about the influence of hull
roughness on flying speed. In particular=2C I was curious about the theory
of sanding boat hulls to gain speed=2C so I decided to ask a championship
small-boat sailor I know about it. Here is is response for improving the
speed of your favorite Grumman:
"By all means sand your wings [to get more speed]. Use 100 grit
paper and work down to 60 grit. Then pound the wings with a large
ball peen hammer with extra attention to the leading edges. Then
down a bottle of Jack Daniels and go flying and you will notice the
difference. Seriously=2C "wet sanding" with up to 600 grit wet or dry
sandpaper used wet is a common "go fast" treatment for sailboat
hulls and I have done it on painted wood boats I have raced."
I wouldn't recommend altering your Grumman's wings according to my
colleague's instructions=2C but in the sailing community some appropriate
application of the boundary effect is known and used. Based on the
deteriorating condition of the paint on my AA-5 upper wing surface=2C I
should have the fastest model around. :)
Cheers=2C
_______________________________________
Roger Rowlett
AA-5 N7159L
KVGC
Message 2
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| Subject: | Re: Wing friction and speed... |
A few years ago, many probably, Hot Rod magazine did an article on skin fri
ction and how it affected drag cars and Indy cars. -Their conclusion: und
er 100 mph, the surface smoothness has a negligible effect. -Between 100
and 150 mph, it had some effect, i.e., the smoother the better. -Over 150
mph, aerodynamics really are the primary factors and controlling flow dire
ction and separation had a big effect. -=0A=0ABottom line is, the brake f
airing fit to the wheel pant has a bigger influence than a waxed wing at to
p speed. -Hell, the VOR antennas create more drag than an unwaxed wing.
=0A=0A=0A________________________________=0A From: Richard Mutzman <rcmutz@
msn.com>=0ATo: Team Grumman <teamgrumman-list@matronics.com> =0ASent: Frida
y, June 22, 2012 8:57 AM=0ASubject: TeamGrumman-List: Re: Wing friction and
speed...=0A =0A=0A =0AAll:=0A-=0AThe visousity of the fluid, the velocit
y of that fluid over the surface, and the length of the surface (ie Reynold
s Number)-are a major players here in how the boundry layer behaves.- B
efore sanding or dimpling your wings, I would recommend you do some serious
reading on boundary layer theory for compressible fluids.=0A-=0APS-- I
know Roger's response is somewhat tongue and cheek we applied to airplane
wings.- =0A=0ARichard Mutzman=0ABSAE, MSAE=0AN399RM=0A-=0AMessage: 5=0A
te.edu>=0ATo: grumman-gang@mailman.xmission.com=0ASubject: Wing friction an
d speed...=0AMessage-ID: <4FDF4148.3050407@colgate.edu>=0AContent-Type: tex
t/plain; charset="us-ascii"=0A=0AOK, I was intrigued by the recent discus
sion about the influence of hull =0Aroughness on flying speed. In particula
r, I was curious about the theory =0Aof sanding boat hulls to gain speed, s
o I decided to ask a championship =0Asmall-boat sailor I know about it. Her
e is is response for improving the =0Aspeed of your favorite Grumman:=0A=0A
"By all means sand your wings [to get more speed]. Use 100 grit=0Apaper and
work down to 60 grit. Then pound the wings with a large=0Aball peen hammer
with extra attention to the leading edges. Then=0Adown a bottle of Jack Da
niels and go flying and you will notice the=0Adifference. Seriously, "wet s
anding" with up to 600 grit wet or dry=0Asandpaper used wet is a common "go
fast" treatment for sailboat=0Ahulls and I have done it on painted wood bo
ats I have raced."=0A=0AI wouldn't recommend altering your Grumman's wings
according to my =0Acolleague's instructions, but in the sailing community s
ome appropriate =0Aapplication of the boundary effect is known and used. Ba
sed on the =0Adeteriorating condition of the paint on my AA-5 upper wing su
rface, I =0Ashould have the fastest model around. :)=0A=0ACheers,=0A=0A____
___________________________________=0ARoger Rowlett=0AAA-5 N7159L=0AKVGC=0A
====================
Message 3
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| Subject: | Re: Wing friction and speed... |
Richard:
"Somewhat"!!! I posted the original on how dirt and sanding would lower
the COF and improve the boundary layer. But Roger is total Tong In Cheek.
Busting grains of sand a bit... Come on 100 Grit and 600 Grit.
Our planes are so unbelievably dirty (as most planes are) you would
not believe it. I have flow my plane without the rubber wing seat seal and
without the sump covers (all at the same time) and there was
NO noticeable difference in speed. There is so much drag created by every
sharp corner - Such as between the fuselage and the wing or
the fuselage and the Horz Stab and the Vert Stab and the turtle deck and
the dorsal fin and the turtle deck and how about the gaping hole and its
counterbalance weight. Want to reduce drag? Work on those! And every
round object such as Gary mentioned (VOR ANT) produces four (4) times the
drag as the same size FLAT object would. So, if you want your plane to
look pretty - Go wash & wax it, we'll all go Oooo and Ahhhhh after you
park. But, forget the Pilot Induced Ballistic Speed (BS) about gains. Oh,
one more speed area - Reduce your vertical step length by 3" and that will
take the step out of the clean air and into the dirty air around the body.
"A 1/4 of a MPH here and a 1/4 of a MPH there and sooner or later you are
Super Sonic" Bob Gibson
Barry
On Fri, Jun 22, 2012 at 11:57 AM, Richard Mutzman <rcmutz@msn.com> wrote:
> All:
>
> The visousity of the fluid, the velocity of that fluid over the surface,
> and the length of the surface (ie Reynolds Number) are a major players here
> in how the boundry layer behaves. Before sanding or dimpling your wings, I
> would recommend you do some serious reading on boundary layer theory for
> compressible fluids.
>
> PS- I know Roger's response is somewhat tongue and cheek we applied to
> airplane wings.
>
> Richard Mutzman
> BSAE, MSAE
> N399RM
>
> Message: 5
> Date: Mon, 18 Jun 2012 10:55:04 -0400
> From: Roger Rowlett <rrowlett@colgate.edu>
> To: grumman-gang@mailman.xmission.com
> Subject: Wing friction and speed...
> Message-ID: <4FDF4148.3050407@colgate.edu>
> Content-Type: text/plain; charset="us-ascii"
>
> OK, I was intrigued by the recent discussion about the influence of hull
> roughness on flying speed. In particular, I was curious about the theory
> of sanding boat hulls to gain speed, so I decided to ask a championship
> small-boat sailor I know about it. Here is is response for improving the
> speed of your favorite Grumman:
>
> "By all means sand your wings [to get more speed]. Use 100 grit
> paper and work down to 60 grit. Then pound the wings with a large
> ball peen hammer with extra attention to the leading edges. Then
> down a bottle of Jack Daniels and go flying and you will notice the
> difference. Seriously, "wet sanding" with up to 600 grit wet or dry
> sandpaper used wet is a common "go fast" treatment for sailboat
> hulls and I have done it on painted wood boats I have raced."
>
> I wouldn't recommend altering your Grumman's wings according to my
> colleague's instructions, but in the sailing community some appropriate
> application of the boundary effect is known and used. Based on the
> deteriorating condition of the paint on my AA-5 upper wing surface, I
> should have the fastest model around. :)
>
> Cheers,
>
> _______________________________________
> Roger Rowlett
> AA-5 N7159L
> KVGC
>
> *
>
> *
>
>
Message 4
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| Subject: | Re: wings and things |
Guys,
I agree with you both on all accounts. Lots of dirty air around a Grumman, and
areas that could be cleaned up.
Btw... I meant to send this to Grumman Gang not Team Grumman.
Richard
Sent from my ipad
Message 5
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| Subject: | Re: wings and things |
It was fun to read it. -=0A=0A=0A________________________________=0A From
: Richard Mutzman <rcmutz@msn.com>=0ATo: Team Grumman <teamgrumman-list@mat
ronics.com> =0ASent: Friday, June 22, 2012 2:29 PM=0ASubject: TeamGrumman-L
hard Mutzman <rcmutz@msn.com>=0A=0AGuys,=0A=0AI agree with you both on all
accounts. Lots of dirty air around a Grumman, and areas that could be clean
ed up. =0A=0ABtw...- I meant to send this to Grumman Gang not Team Grumma
===========
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