Le samedi 25 juin 2005 à 13:53 -0400, Josh Babcock a écrit :
> Gerard Robin wrote:
> > Le samedi 25 juin 2005 à 13:16 -0400, Josh Babcock a écrit :
> >
> >>Vivian Meazza wrote:
> >>
> >>>Josh Babcock
> >>>
> >>>
> >>>
> >>>I have a nagging memory that the Wright Cyclone R-3500 was fitted with
> >>>reduction gearing between the crankshaft and propeller, although I can't
> >>>find any reference to it right now. Do you have any details of the ratio?
> >>>It's needed to migrate to the new Yasim propeller definition.
> >>>
> >>>You could use the R-2600 ratio, I suppose:
> >>>
> >>>Propeller Reduction Gear Ration (crankshaft to propeller): 16:9
> >>>
> >>>That comes from here:
> >>>
> >>>http://wrightpattjobs.wpafb.af.mil/museum/engines/eng42a.htm
> >>>
> >>>V.
> >>>
> >>>
> >>>
> >>>
> >
> > Only for the fun, and may be seriously i can try to calculate it with
> > the help of the new aeromatic propeller, i have implemented it locally.
> > I need: Engine RPM -- Propeller diameter (inch or feet) -- Engine power
> > ( HP or KW without boost).
> >
> >
> 2700 rpm
> 16'7" (4 blades)
> 2200 hp
>
> Josh
>
=================================================================
The results, i notice the calculation gives 3 blades with 2200 HP
Inputs:
horsepower: 2200
pitch: variable
max engine rpm: 2700
prop diameter (ft): 16.7
Outputs:
max prop rpm:1123.53
gear ratio: 2.40
Cp0:0.059661
Ct0:0.051308
static thrust (lbs):3327.61
-->
<propeller name="prop">
<ixx>54.2414 </ixx>
<diameter unit="IN">200.4 </diameter>
<numblades> 3 </numblades>
<gearratio>2.40 </gearratio>
<minpitch> 12 </minpitch>
<maxpitch> 30 </maxpitch>
<minrpm> 899 </minrpm>
<maxrpm> 1124 </maxrpm>
====================================================================
Again with 2400 HP we get 4 blades (min rpm and max rpm are the same)
Inputs:
horsepower: 2400
pitch: variable
max engine rpm: 2700
prop diameter (ft): 16.7
Outputs:
max prop rpm:1123.53
gear ratio: 2.40
Cp0:0.065084
Ct0:0.055972
static thrust (lbs):3630.12
-->
<propeller name="prop">
<ixx>72.3219 </ixx>
<diameter unit="IN">200.4 </diameter>
<numblades> 4 </numblades>
<gearratio>2.40 </gearratio>
<minpitch> 12 </minpitch>
<maxpitch> 30 </maxpitch>
<minrpm> 899 </minrpm>
<maxrpm> 1124 </maxrpm>
I don't know if it will be useful.
>
>
>
--
Gerard
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