Prop mass and bsfc figures for YASim

> -----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



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