Please turn word wrap on.

*********************************************************
PROP DOUBLE FLOATING POINT VARIABLE?
S. M. Baugh, Ph.D.
smbaugh@adnc.com (home)
smbaugh@wtscal.edu (work)



Both AirEd and FDE evaluate four variables in section 500 of the .air file (Recip Engine) as two byte integers and suggest that they refer to "Prop MOI." I have played with these values quite a bit and noted that changing the first three seems to make no difference, while changing the last does somewhat. Further, in some of the default planes, the first three values are zeros. I had been expecting this value to correspond to the number of prop blades, but it does not in the different MS default airplanes.

I have also noticed correspondence between the structure of these numbers and others in section 1101, and am now suggesting that rather than seeing these numbers as 4 sets of 2 byte integers, that they should be read as one double word floating point value. Hence, the FDE control file, instead of reading:

500,36,Prop MOI? 500-36,Integer2,1                     
500,38,Prop MOI? 500-38,Integer2,1
500,40,Prop MOI? 500-40,Integer2,1
500,42,Prop MOI? 500-42,Integer2,1 

should be changed to this line:

500,36,Prop MOI? 500-36,Float8,1

(Comparable changes can be made to AirEd's AirEd.ini file, but you will have to renumber the subsequent entries in section 500. Use the "double" data type.)


The exact purpose of the value still eludes me, but it seems better to look at it as one value which corresponds roughly to the prop size (see below for default values). I intend to look at this further myeself, but I welcome any suggestions here.

Steve Baugh


************************
FS98/CFS Default Planes:

(Note: The value 5.70 is found in both the Bell 206B and Schweizer
glider .air files here, but I believe that these are "residues" from the FS98 converter that are unused by FS98 for these craft.)


Cessna 182 and 182RG
1. 5.70 (82" prop)

Extra 300S
1. 5.90 (74" prop)

Sopwith Camel
1. 5.70 (84" prop)


CFS P-47 Thunderbolt
1. 86.5 (156" prop)

CFS P-51 Mustang
1. 58.0 (134" prop)

CFS Hawker Hurricane Mk I
1. 34.3 (129" prop)

CFS Spitfire Mk I and Mk IX
1. 26.8 (114" prop)

CFS Fw 190A
1. 62.0 (130" prop)

CFS Bf 109E and 109G
1. 32.8 (122" prop)

********************
Default FS98 Converter?
1. (varies)



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