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let me clarify: if you use the K&M smoothing technique, but are only able to
reduce the opening a "little" bit, instead of down to 9 in^2, you may get
the same or improved cooling with lower drag. Just don't throw out the idea
if 9 in^2 isn't the final answer.
Bill
----- Original Message -----
From: "Ed Anderson" <eanderson@carolina.rr.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Thursday, September 04, 2003 8:09 AM
Subject: [FlyRotary] Re: Downsize inlet duct First Flight
> Point well taken, Bill. However, my cooling was more than adequate with
the
> old larger ducts, so unless I can get some benefit (like lower drag), I
> don't see much point. On the other hand, if I added a turbo producing
more
> waste heat then that would help there with the same size ducts. I'll
> continue to see what I can do with it.
>
> Ed
>
>
> Subject: [FlyRotary] Re: Downsize inlet duct First Flight
>
>
> > Ed, you might get even better cooling, although no change in drag, by
> > keeping the opening large, but using the smoothing technique that you
> tried
> > on the smaller opening.
> > Bill Schertz
> > ----- Original Message -----
> > From: "Ed Anderson" <eanderson@carolina.rr.com>
> > To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> > Sent: Wednesday, September 03, 2003 7:18 PM
> > Subject: [FlyRotary] Downsize inlet duct First Flight
> >
> >
> > > The modification (reduction) of my radiator inlet duct area from a
total
> > of
> > > 48 square inches to 33 square inches is dedicated to Rusty (for
obivious
> > > reasons {:>)) Sorry, just couldn't help myself, Rusty, - the devil
> made
> > me
> > > do it.
> > >
> > > Ok folks, made the first flight today with my reduced/reshaped
radiator
> > > > inlet for the left evaporator core. The right evaporator core was
> left
> > > > unmodified to provide a safety net sufficient to do the pattern and
> > land
> > > if
> > > > take off temps exceeded expectations. Fortunately, that was not
> > > necessary.
> > > > OAT on first take off was a humid 85 degrees. No temperature
> increased
> > > > noted during ground run up, so launched and made max rate of climb,
> not
> > > > seeing any abnormal temp increase I left the pattern and continue
Max
> > rate
> > > > climb to 4500 MSL. Max temp of coolant during climb was 210F
(normal
> > for
> > > > max rate climb at these OAT temps is 205F), Max oil temp was 200F
> > nominal
> > > > for max power climb. Max temps were reached about 2/3 of the way
> through
> > > the
> > > > climb.
> > > >
> > > > In level flight, my coolant temperatures normally run 5 degrees
colder
> > > than
> > > > my oil temp. Today my coolant and oil temps were the same. So
> average
> > > > coolant temp was increased by 5 Degrees F. Total radiator inlet
duct
> > area
> > > > was decreased from 48 square inches to 33 square inches. 24 Square
> > inches
> > > > for the right inlet duct and 9 square inch inlet for the modified
> right
> > > > duct (See attached photo for comparision). Probably some drag
benefit,
> > but
> > > did not try to investigate that
> > > > aspect.
> > > >
> > > > I flew to an airfield 50 miles away to have my transponder
recertified
> > and
> > > > when I launched out of it, the OAT (ground level) was 92F
> > > >
> > > > After level off I ran at different power settings to see the effect.
> > > >
> > > > 5800 rpm burning 11.9 GPH at 4500 MSL with OAT at 78F My oil and
> > > coolant
> > > > were both 190F.
> > > >
> > > > 5400 rpm burning 9.6 GPH at 4500 MSL with OAT 80F My Oil and coolant
> > were
> > > > both 185F
> > > >
> > > > 5200 (Around my normal cruise rpm) burning 7.25 GPH at 4500 MSL
with
> > OAT
> > > 80F My
> > > > oil and coolant were both 180F
> > > >
> > > > In summary, the 33 % reduction in total radiator inlet area
appeared
> to
> > > > have increased coolant temps by an average of 5 Deg above the normal
> > (the
> > > > old duct). It could be that both the remaining radiator and perhaps
> the
> > > oil
> > > > cooler are rejecting any additonal load with no problem.
> > > >
> > > > It appears that smoothing out the path for the air from inlet to
> > radiator
> > > > surface has benefited the cooling situation. It could be that
> > additional
> > > > heat may be rejected by the right (second in series) radiator as the
> > > coolant
> > > > it received from the left radiator was probably now a bit hotter. I
> also
> > > > observed that the plate of the PSRU covers an area 3 " in from top
to
> > > bottom
> > > > of the rear of each radiator and the plate is only 2" from the rear
of
> > the
> > > > fins at its closest, so that is obviously not helping flow, the Ross
> > Bell
> > > > housing did not, so a bell housing might improve flow conditions .
> > > >
> > > > I strongly suspect I would probably find that a similar reduction
> of
> > > the
> > > > right radiator inlet duct to 9 square inches would see my coolant
> (and
> > > > probably oil) temps increase considerable more than another 5 F.
> > >
> > > OAT at ground level was 94F when I landed, so not the hottest of
days,
> > but
> > > not the
> > > > type I normally prefer to fly in.
> > > >
> > > > >From what I have seen so far, I think it worth pursuing a reduction
> > with
> > > the
> > > > right radiator duct. I will probably not reduce it as much for the
> > reason
> > > > mentioned above. With some other things to take care of, probably
> won't
> > > get
> > > > to it until later part of Sept at the earliest. But, I have no
> problem
> > > > flying with current asymmetrical ducts, so will leave it as is for
the
> > > time
> > > > being and collect some more data.
> > > >
> > > > It it appears that some cooling benefit is derived from providing a
> > > smoother
> > > > transition from duct to radiator (even if far from a perfect
> > > implementation
> > > > of the K&M approach) than my old duct provided. The volume of the
> duct
> > > was reduced by at least 60%, so while hard to tell from photos the
white
> > > "filler" material actually fills most of the duct.
> > > >
> > > > Oh, yes, as an aside, its been 25 hours since I replaced the spark
> plugs
> > > and
> > > > right on schedule - on the way back, I got the first SAG (Sparkplug
> > > > Attention Getter) indication. So it appears 25 hours on 100LL
about
> > the
> > > > average time for replacing plugs in my case. I finally got a spark
> plug
> > > > cleaner, so need to clean a set (as the electrods do not appear
worn)
> > and
> > > > see if getting the lead off the ceramic cone helps any.
> > > >
> > > > Best Regards
> > > >
> > > > Ed Anderson
> > >
> > > Ed Anderson
> > > RV-6A N494BW Rotary Powered
> > > Matthews, NC
> > > eanderson@carolina.rr.com
> > >
> >
> >
>
> --------------------------------------------------------------------------
> --
> > ----
> >
> >
> > > >> 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
> >
>
>
>
> >> Homepage: http://www.flyrotary.com/
> >> Archive: http://lancaironline.net/lists/flyrotary/List.html
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