REFLECTOR: Molding a P-51 Scoop

[Joe Ewen]

Scott,
I should have my radiator from Griffin the week after next.  I too will be
mounting it P-51 style.  While doing homework on size air flow etc., I came
across info regarding streamline diffusers (Aerodynamics Of Propulsion).  A
4:1 or 3:1 seemed to be the best combination at least for my configuration.
2:1 moves a lot of CFM but short dwell time and higher drag.  I am planning
my intake scoop with changeable diffusers, initially using a straight line
diffuser with a 5 degree angle (approximately 2:1) to ensure I have more
than enough cooling for initial test flights.  If cooling proves to be more
than adequate, the diffuser will be replaced with a K&W streamline at a 3:1
and ultimately 4:1 to reduce drag.  If interested in the streamline
diffusers, you can find a lot of info and discussion on the FlyRotary mail
list.

Thanks to some pictures and info Al Gietzen proved some months ago, I am
planning my oil cooler and intercooler will be wing root cooling units.

Joe


----- Original Message ----- 
From: "Scott Derrick" <scott at tnstaafl.net>
To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
Sent: Monday, September 05, 2005 9:33 PM
Subject: Re: REFLECTOR: Molding a P-51 Scoop


> Jim,
>
> The intercooler face is 6x22, I thought I read some formula that a
> 1-to-2 expansion area in front of the intercooler was a good thing.
>
> I will reread my turbo book and verify what I need.  I agree, it seems
> like a whole lot of area. I would think 1/4 of that would do.
>
> Scott
>
> Jim Sower wrote:
>
> > Isn't 66 sqin nearly the size of the engine cooling inlet?  Sounds
> > like a lot.  I would have thought maybe 30% of that would do.  Anyway,
> > Urethane foam is cheap and carves easiest, Styrofoam will melt away
> > with gas.  I use duct tape or plastic/shrink wrap as a release agent.
> > I'd revisit my sizing formula ... Jim S.
> >
> > Scott Derrick wrote:
> >
> >> I need to make a P-51 style scoop for my intercooler.
> >>
> >> It needs to have a 3 inch x 22 inch opening.
> >>
> >> Roughly rectangular, this would be mounted on the belly right at the
> >> firewall.
> >>
> >> What would be the best way to go about this?   Carve one out of foam?
> >>
> >> Any ideas are appreciated.
> >>
> >> Scott
> >>
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