Larry, I mis-spoke (Notching the piston for power)

[fahrvegnugen at cox.net (David Utley)]

Responses within...
> 
> From: Lars Bruchmann <pilotlars@yahoo.com>
> Date: 2004/09/14 Tue AM 12:05:50 EDT
> To: David Utley <fahrvegnugen@cox.net>,  Larry Fry <rocco16@sbcglobal.net>, 
>   scirocco-l@scirocco.org
> Subject: RE: Re: Larry, I mis-spoke (Notching the piston for power)
> 
> i have never heard of hail-damaged aircraft flying
> faster, except maybe for the pilots trying to get the
> aircraft to the ground before it is destroyed
> completely.  modern aircraft have super-critical wing
> and fuselage shapes, the boundry layer is extremely
> close to the surface.  dimples would not help.  
> the dimples in a golf ball create an 'artificial
> boundry layer' which lets the ball fly farther. 

Here is where the dimples can help, by creating an artificial boundry layer...

> aircraft have VGs (vortex generaters), strakes and
> fences on wing surfaces to do the same thing. 
> a dirty aircraft will not fly as fast, since the dirt
> actually raises the boundry layer, and creates drag. 
> a wet aircraft will not fly as fast either.  ice is
> the worst, there is a type of ice that forms, which is
> kinda dimpled, and it is really bad news.  so, as far
> as i'm concerned, dimples are bad for aircraft.  but
> they could be great for indian cars! :-) 

All the examples you listed extended upward from the surface, and/or added weight, and this would not help.  The dimples would be inward, so this would not be an issue in that regard...

You are more savy with planes, and the like...  I invite you to do some research in this area.  I have tried, but I am not as knowledgeable here as you, so you prolly have a better idea of where to look...

Hope that helps explain it a bit more...  Maybe...


Cheers,
  David

> --- David Utley <fahrvegnugen@cox.net> wrote:
> 
> > 
> > 
> > -----Original Message-----
> > From: Larry Fry [mailto:rocco16@sbcglobal.net]
> > Sent: Monday, September 13, 2004 9:21 PM
> > To: fahrvegnugen@cox.net; scirocco-l@scirocco.org
> > Subject: Re: Re: Larry, I mis-spoke (Notching the
> > piston for power)
> > 
> > Why do we care how fast the intake air travels
> > "across the piston"?  Once
> > it's inside the combustion chamber, it's a moot
> > point, since the old-tech
> > design of our engines is not of the 'high-swirl'
> > type anyway.
> > As usual, I'm a bit skeptical of stuff like
> > this....but, when I hear of
> > Roush, or Yates, or Lingenfelter dimpling their
> > pistons I will reverse my
> > postion.
> > :)
> > Larry
> > 
> > Larry,
> >   They would have, had they been doing NASCAR back
> > in the eighties.  You
> > know, like when our cars were made?  Besides, the
> > argument that our cars are
> > too old-tech a design to benefit seems weak as well.
> >  Megasquirt is about as
> > new as it gets, and I think that all here that have
> > experience with it would
> > argue that it is VERY beneficial...  Besides, yours
> > is a 16V, yes?  It is
> > high enough a compression to benefit...
> > It seems our arguments as of late seem to be more
> > about logic and sophistry,
> > rather than engineering...  What's up?  :)
> > 
> > David
> > >   What I am suggesting is putting dimples in the
> > piston face, not the
> > perimeter...  Air at speed does not do well with 90
> > degree, much less 180
> > degree changes of direction.  These dimples, or
> > pockets of air, create a
> > cushion of air that acts as a buffer.  As the air
> > travels over the surface
> > of something, the air is slowed by the difference in
> > speed of the two.  The
> > pockets acts a buffers in this regard, allowing the
> > air to travel more
> > quickly across the surface.
> > >
> > > I tried to find something via Google, about
> > jetliners with hail damage
> > actually flying faster, but could turn up nothing...
> >  You have seen the
> > commercial for Lexus, haven't you?  I might find
> > more if I looked at golf
> > ball history, I don't know...  What I do know is
> > that this works...  :-)
> > >
> > > Cheers,
> > >   David
> > 
> > 
> > _______________________________________________
> > Scirocco-l mailing list
> > Scirocco-l@scirocco.org
> > http://neubayern.net/mailman/listinfo/scirocco-l
> > 
> 
> 
> 
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