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Ed - thanks for your reply. I'm building a 3 rotor so the numbers are even
bigger. it sounds feasible that a spray bar might provide the added cooling
needed for take off. I have built a belly scoop, but don't see any problems
with mist on the tailcone. (hell, my current -6A has a pilot relief tube, if
you want to talk about corrosion!) it's the exhaust out the side that will
probably be my big problem. I am building the intake plenum right now so
should look at sprayers to install around the inlet.
Kevin Lane Portland, OR
e-mail-> n3773@comcast.net
web-> http://home.comcast.net/~n3773
(browse w/ internet explorer)
----- Original Message -----
From: "Ed Anderson" <eanderson@carolina.rr.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Saturday, December 06, 2003 6:46 AM
Subject: [FlyRotary] Re: spray bars
> Kevin,
>
> A spray bar can be very effective as you are using the latent heat of
> evaporator of water. If my calculations are correct, it takes approx
> 7773 BTU of heat to vaporize a gallon of water. So quite a bit of heat is
> used.!
>
> I calculate that if producing 160 HP at take off and taking 3 minutes to
get
> to 120MPH IAS where the airmass flow would handle the heat of 160HP, you
> would need to get rid of approx 15,000BTU of heat (total over the 3
> minutes - approx 5000 BTU/min) from the coolant radiators.
>
> 3 gallons of water (assuming it all evaporated- which of course, it would
> not, as some would be blown through the core unevaporated - 50%? just
don't
> know) would provide 22,345 BTU of heat dissipation. So 3 gallons would
> theoretically take care of your complete radiator cooling needs for the
> first 4.5 minutes. But, since, your radiators would also be rejecting
some
> of the heat through the air mass flow (just not quite enough), the 3
gallons
> (even if only 50% evaporated) would probably be quite a bit more than you
> needed for one take off.
>
> Then you would need to figure out the spray flow rate so you wouldn't be
> spraying more water than the core heat could evaporate and therefore
wasting
> it. You would also need to figure out an adequate spray pattern,
build/buy
> the nozzles, water pump, water container, etc. But, certainly doable.
> Tracy Crook at one time used one when he was being held on the ground for
> extend periods and needed more cooling than airflow from prop was
providing.
>
> Don't know what the down side of continuos use might be. That's lot of
> water vapor under the cowling, but most would of course blow out -
however,
> corrosion might be a consideration.
>
> My $0.02 worth
>
> Ed
>
> Ed Anderson
> RV-6A N494BW Rotary Powered
> Matthews, NC
> eanderson@carolina.rr.com
> ----- Original Message -----
> From: "kevin lane" <n3773@comcast.net>
> To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> Sent: Saturday, December 06, 2003 1:13 AM
> Subject: [FlyRotary] spray bars
>
>
> > in all this discussion about thick cores, since I am building a p-51
style
> > 5" core myself for my -8, I wondered how effective a water spray bar
would
> > be for the few minutes of critical climbout airspeeds. how effective is
a
> > spray bar? it seems stupid to have a larger radiator to handle a very
> small
> > portion of the flight. would that much water need to be carried for a
> > typical flight?
> > Kevin Lane Portland, OR
> > e-mail-> n3773@comcast.net
> > web-> http://home.comcast.net/~n3773
> > (browse w/ internet explorer)
> > ----- Original Message -----
> >
> >
> >
> > >> Homepage: http://www.flyrotary.com/
> > >> Archive: http://lancaironline.net/lists/flyrotary/List.html
>
>
>
> >> Homepage: http://www.flyrotary.com/
> >> Archive: http://lancaironline.net/lists/flyrotary/List.html
>
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