Message-ID: <001201c398e1$80ad2400$1702a8c0@WorkGroup>
From: "Ed Anderson" <eanderson@carolina.rr.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-2647116@logan.com>
Subject: Re: [FlyRotary] Re: New cooling Model example
Date: Wed, 22 Oct 2003 17:14:37 -0400
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Hi Jim

To answer your question, I have already done that.  You can now stick in any
gear ratio you want.  However, the only thing that it really changes is the
prop rpm.  In other words, this simple model does not yet have a "load
factor".  I hope to be able to add that at some time in the future, but the
problem from what little bit I know about propellers is that it would take
some math model of prop loading on the engine, thrust and airframe drag
factors. Then that would mean either everbody would have to know same for
their airframe, or some sort of simplistic model would have to be used.

 So while the model does permit your to put your gear ratio in.  I'm afraid
all it really does is calculate your prop speed for you.  Sorry 'bout that.

However, the model will calculate the rest of the stuff IF you can achieve
that rpm with your prop load (whatever that rpm may be).  You can also put
in one or three rotors (or 4 or more if you want).  I feel 90-95% confident
that the power and BTU calcuations are within 5% (perhaps less) of the real
world based on data I have received.  That of course assumes you have a
good induction and exhaust system.  If a bad one, then all bets are off.

If you would like a copy of the spreadsheet as it now stands let me know.

Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com
----- Original Message -----
From: <DELTAFLYER@prodigy.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Wednesday, October 22, 2003 4:25 PM
Subject: [FlyRotary] Re: New cooling Model example


> Ed,
> Some of us real "radical" rotor heads are using the
> 2.85:1 ratio drive. I was wondering if you could
> modify your spreadsheet model to allow other drive
> ratios? This may help some of us to better model our
> systems and make the proper choices for the other
> system components.
> Thanks,
> Jim Maher
> (Dyke Delta/13B)
> --- Original Message ---
> From: "Ed Anderson" <eanderson@carolina.rr.com>
> To: "Rotary motors in aircraft"
> <flyrotary@lancaironline.net>
> Subject: [FlyRotary] New cooling Model example
>
> >Ok Folks,
> >
> >    I've been messing around with the cooling model
> of the spreadsheet that
> >some of you have.
> >I don't want to send out dozens of spreadsheets which
> are in the development
> >phase and have 47 different version out there.  So I
> am only going to send
> >out some results of the latest models in the
> spreadsheet and ask for
> >comments.
> >
> >Once it appears that the model is approaching some
> degree of realism and
> >usefulness, then I will be happy to provide everyone
> with it.
> >
> >Right now, I am concentrating on the evaporator core
> models.  However, my
> >intention - if it works out with the cores - is to
> broaden this so other
> >folks not using the cores can make use of it as well.
> >
> >I realize that some of you may not have much more
> insight into what
> >"realistic" might intale than I do, but I have a
> great deal of faith in the
> >keen analytical minds out there to provide some
> useful input (How about that
> >for stroking the egos{:>))
> >
> >I have attached a spreadsheet with the results of
> three cases using the
> >model.  The all involve an aircraft taking off in
> early climb out producing
> >150 HP.  The three cases involve climb out, high
> power and low airspeed.
> >Case 1.  Climbout is made on a 20F day with 150HP at
> just fast enough
> >airspeed to provide minimum adequate cooling.
> Case2.  Climbout is made on a
> >90F day with the same power and airspeed conditions
> as case 1.  The model
> >shows the cooling capacity is exceeded.  Case 3.
> Then holding everthing the
> >same  as case 2 including power and 90F OAT, I
> increase the airspeed (and
> >therefore mass flow) until at 117 MPH we again barely
> achieve adequate
> >cooling on the 90F day.  Note that the delta T
> changes for each case.
> >
> >There are some comments and notes with each case.
> Take a look and if
> >inclinded I would greatly appreciate any feedback.
> >
> >
> >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