Re: Prop mass and bsfc figures for YASim

On Saturday 05 February 2005 17:02, Jim Wilson wrote:
> > -----Original Message-----
> > From: Lee Elliott <[email protected]>
> > Sent: Saturday, 5. Feb 2005 8:27 -0500
> > To: [email protected]
> > Subject: [Flightgear-flightmodel] Prop mass and bsfc figures
> > for
>
> YASim
>
> > Hello all,
> >
> > I\'m looking for some prop mass and turbine engine bsfc
> > figures for the SR-45 I\'ve been working on.
> >
> > I\'ve got a flying fdm using guesswork values of mass=4000
> > and moment=50 for the 4-bladed, 2.29 radius props but I have
> > little confidence in them.  Does anyone have any idea of
> > what the typical ball-park figures should be?
> >
> > I\'m also not specifying a value for the turbine bsfc yet
> > (eng-power=3200) and it looks as though all the fuel is
> > gulped down in < 1 sec.  Here too, does anyone have any idea
> > of ball-park figures I could try using?
> >
> >
> >From the comments in p51d.xml:
>
> <!-- moment calculated using formula submitted by Donald
> Simon: MOI = # of Blades * (8.2*(10^-5))*(D^5), slug-ft^2 then
> converted to kg-m^2 and finally square root to kg-m for torque
> value
> -->
>
> D is the diameter in feet, to get MOI in slug-ft^2.  My calc
> is 239 slug-ft^2 for
> 4 blade, 2.29 radius.  The mass is the weight of the engine
> plus a whatever you
> think a prop that big would weight...probably 200+lb.  If you
> know the make and
> model of the engine then you could probably find it.
>
> Best,
>
> Jim

Ta for that.  I've just found out that a later variant of the 
Bristol Proteus was used in the Brittania so I might be able to 
get some usable data by researching that a/c.

LeeE

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