Please note: Any text in BLUE (that is not a link) was
added by me. I also cleaned up the questions at the very end. If there is an
error or ommission please let me know.
FM
FAQ Version 6.2
Q. If I only remember one thing after reading this FAQ what should
it be?
A: DOCUMENT ALL YOUR CHANGES. If someone has to take up where you left
off they will have to throw your plane away unless YOU leave a record of WHAT you changed
and WHY. Be specific! List the sources of your information !
Q. What DOS commands do I need to know?
A.
1) Type the letter of the drive you want to use followed by a colon and hit enter. For
example type E: and press enter to go to your E drive
2) Type DIR and press enter to see a list of files in the current folder
3) Type CD followed by the directory name to change directories into another folder for
example CD OpenPlane
4) Type CD .. and press enter to go up a directory
5) Type notepad filename.asc to edit a file. For Example notepad typh.asc If the file is
too large for notepad you will be prompted to open the file with wordpad. Click on YES.
Q. What tools to I need to modify planes and how do I get started?
A:
Step
1) Make sure you have at least 20 megs or so hard drive space free
2) Download Hippie's OL8 from the Tools Window
3) Download the parfile tools From the Tools Window. When you click on the link at the
bottom, select the directory you want to save the file to and change the name to
ParFileTools.zip
4) Make a directory on your hard drive called OpenPlane
5) Unzip both the files into this directory
6) Run the BigMunger Program from your OpenPlane directory
7) Click on the unbig tab
In the path to bigfile box type in the name of your data13.par file from the latest plane
pack. For example E:\Fighter Squadron\media\data13.par
9) Make a directory called PlanePack
10) In the destination directory box type in the name of your planepack directory for
example C:\PlanePack
11) click the OK button. When the program finishes you should have all the plane pack
planes extracted into your planepack directory
12) Go into the the PlanePack\aircraft directory and find the plane you want to work on.
Lets use the typhoon as an example so go into the typh directory.
13) Click on the file typh.sm, then press control-C. Now go to the directory you put all
your tools in (OpenPlane) and press control-V to make a copy of the typhoon there.
14) Click on the start menu, then programs, then Command Prompt. A box will open, use type
CD C:\OpenPlane
and hit return.
15) Type
extractor typh typh
16) Type
notepad typh.asc
17) Use notepad to search for the word 'CYL do not forget the quote. There will be three
of these, the first two provide drag on the gear, the third represent the drag of the
fuselage. When you get to the third 'CYL line, you should see:
(obAirfoil (airChord 34.2658 airPt 0,-8.56644,0 airArea 176.121 ))
Just for fun, try changing airArea to something like 976.121. This will cause more drag on
the plane, reduce it's top speed and gliding ability.
Save the file
18) At the command prompt, type:
builder typh typh
1 Congratulations you changed a plane! Copy the typh.sm file from your openplane directory
to your Fighter Squadron\media\aircraft\typh (you may have to create these subdirectories)
19) Fire up SDOE and take the tiffie for a test drive, you should notice it flies
different.
*See the tools link on this page if you need to download them.
Q: How do I calibrate a plane for climb rate and top speed?
1) Determine the top speed of your plane at different altitudes. Determine the plane's
climb rate. Determine wing area and wing span. Determine the weight of the plane including
a combat load with guns and ammo but no fuel or bombs. NOTE this is DIFFERENT from empty
weight. Most of this information is available on the internet or I can send it to you if I
have it.
3) Take the wingspan and multiply it by itself. Divide the result by the wing area of the
plane. This will give you the Aspect Ratio of the wing.
4) Plug this number into the airAR property of the airfoil for the wings. You can do this
using OPStudio or the builder method mentioned above. In our Typhoon example the two lines
you are looking for say: (airWing airSection "TYPHfoil" airK 0.6 airAR 8.25
airAdvantage .5 airMax .75)
If you are using builder you can find them by searching for "modelname:
leftWing" and "modelname: rightWing"
5) Build and test the speed of the plane at different altitudes. Test the climb rate (we
need to all use the same method to test climb rate).
6) I'll give a table of the different test results and how you can fix the problems.
H means speed too fast up high
h means speed too low up high
L means speed too fast down low
l means speed too low down low
c means climb rate too low
C means climb rate too high
HLC - add more drag
Increase 'CYL area, decrease airK value on wings and vstab
airK should be LEFT ALONE, this does little to increase drag but affects other flight
characteristics you don't want affected
hLC - Increase max prop pitch, increase drag
HlC - decrease drag, increase prop pitch, reduce prop size
HLc - decrease max prop pitch
Hlc - decrease drag decrease max prop pitch
hLc - increase drag decrease max prop pitch, increase prop size
hlc - increase prop size
Do not increase max pitch beyond 70 or so.. at 90 degrees the prop is totally flat and not
much use.
Depending on the amount of twist in the propeller, the prop stalling may occur before 70
deg
To make performance drop off or enhanced at higher altitudes make the blades fatter for
better performance or skinnier for worse performance.
Q: How do I trade off between climb rate and top speed
without altering drag or the propeller?
If you don't have the actual engine gear ratio you can modify this.. a lower gear ratio
will give you better climb and lower top speed, a higher gear ratio will give you better
top speed and worse climb.
This one's from Zurawski:
High-pitch & high-rpm = high top-speed .. low torque (poor climb)
Lower-pitch & higher rpm = better climb
Note that setting max pitch too high will make the propeller stall and perform poorly at
high altitude.
Q: How do I increase drag?
The planes in SDOE often do not have enough drag for whatever reason. I think it's because
drag on the cockpit and nose are not modeled, could be the air is too thin, I'm not sure I
haven't been able to pry the information out of MH. Anyway to increase drag search for the
'CYL airfoil representing the fuselage and increase the area of it. This will have two
effects.. slightly increasing lift and greatly increasing drag. Not the best solution but
oh well. See the first question in the FAQ for an example of increasing drag.
Q: How do I change max Prop pitch?
Search for the property "propMaxPitch". Increasing this value makes the plane go
faster and reduces it's climb rate. Decreasing this value makes the plane go slower but it
climbs better and has a greater P-factor (torque)
Q: How do I change propeller size?
Search for the property PropRadius. Increasing this makes the plane go faster and climb
better at lower altitudes but go slower and climb worse at higher altitudes. An
alternative to changing prop size can be to change the propelements list that defines the
shape of the propeller. Its pairs of numbers specifying angle, area. Increase each area
value by a small amount to get better climb and top speed.
Q: How do I set the plane weight?
Search for the property CAircraft. The Typhoon looks like this:
(obProto 'CAircraft obClass 'fighter phyLBS 8600)
This means the plane weights 8600 pounds without fuel or bombs but with guns and ammo.
Make sure any values you research correspond to this loadout. In a pinch you can increase
plane weight to decrease it's climbing ability but this can affect handling and the
threshold for gear damage.
Q: How do I go back to using the original plane or base pack
planes?
A: Just remove any .sm files you copied to your aircraft directory and you will be back to
normal.
Q: When calculating the weight of the plane, I know I
should leave out fuel but what else do I need to add to the dry weight of a plane?
A: Here is an example from the spitfire:
2 Browning .50 gun and accessories 162.5 lb
Ammunition 130lb
2 Cannon and accessories 297.5 lb
Cannon ammunition 130 lb
Gyroscopic gun sight and lamps 8.5 lb
1 lb incendiary bomb, clock and crowbar (????? LOL) 3 lb
Gun Camera, adaptor, front flange and indicator 7 lb
Oxygen in 3 cylinders 7 lb
Dingy 18.5 lb
Radio and accessories 80.5 lb
Radio, Detonator and Control Unit 35lb
Pilot and Parachute 200lb
They Call this the "Total Typical Removable Military Load" and of course it
varies from plane to plane. Note that SDOE adds the weight of the pilot at runtime, so
leave that part out.
It also lists oil in the spit as 101.5 lbs. SDOE doesn't model oil usage/weight/loss so we
have to add that.
You can double check the weight of the plane by adding this line to your sdemons.ini file:
ShowVehicleWeights = 1
Now when you F5 through the planes you will be able to see the weight of all planes
including fuel and bombs.
DO NOT add the weight of the ammo for dry weight. If you assign inertia boxes to the guns,
the ammo weight will be added when the loadout file is read
Q: Do loadouts affect plane weight and Center of Gravity?
A: Bombs do alter the weight and CoG, ammunition doesn't. I don't think ammunition makes a
big impact anyway.
Depending on the amount and type of ammo, it can have a noticeable affect on the CG.
Because the planes were originally released without inertia objects assigned to the guns,
the ammo in the loadout had no effect and lead to this misconception
Q: Why do the planes glide so well?
A: The current plane models do not account for drag created by the cockpit, oil coolers,
and the nose of the plane. I had to add a bunch of drag to the Spit IX to get it to match
specs, the cockpit and the oil coolers, nose etc are not factored into the model at all so
I had to add extra drag to compensate. I think this is why all the planes glide so well.
Q: How heavy is fuel and oil?
A: 9lb/gallon for oil and 7.2 lb/gal for 100 octane aircraft fuel. These weights are for
English gallons not US gallons. I think SDOE uses US gallons. 1 US gallon 0.8327 UK gal,
or 1UK gal = 1.2 US Gallons. Make sure to do the conversion if you are setting fuel tank
capacity on non-US planes.
Q: How do I adjust roll rate?
A: If the roll rate is too fast at all speeds, lower the airmax value for the ailerons. If
the roll rate is too fast at high speed, decrease the airadvantage property for the
ailerons. If the roll rate is too slow at high speeds, increase the airadvantage property
for the ailerons. Make sure to set these values so the same for both elevators.
Q: How do I make the plane harder to pull out of dives?
A: Decrease the airadvantage property for the elevators. Make sure to set this value the
same for both elevators.
this will also affect the turn rate at varying speeds so you may need to go back and
readjust the airMax values
Q: What does airMax do?
A: Airmax determines the range of travel for the control surface. A value of 1 is 60
degrees total travel (30 degrees each way from center). A value of 0 means no travel. A
value of 0.5 would be 30 degrees or 15 degrees from center each way. You can calculate
airmax from degrees by dividing by 60.
For example, if you have plane specifications that say the aileron traveled 10 degrees
each way, 20 / 60 = 0.333 for an airmax value. Note that it is not possible to specify
non-symmetrical travel. IE most ww2 planes had rudders that travel farther one direction
than the other. This is not currently possible using airMax.
This is curently the biggest misconception in SDOE. The non-symmetrical travel IS
accounted for when the airfoil data for control surfaces up and down is gathered. AirMax
is a fudge factor to allow for variations in the physics model and the fact that there may
be some deviations in the area of the airfoil from real life. If the airfoil data is
gathered correctly, ther is a difference in the lift and drag calculated from the control
surface being moved to it's maximum deviation in either direction
Q: How do I set or verify engine gear ratio?
A: If you have the engine gear ratio for your plane it's probably something like 0.5, to
use this in SDOE you need to take the reciprocal (1 divided by 0.5) which gives you two.
Q: How do I increase/decrease performance at high altitudes
compared to down lower?
A: Make your propeller blades 'skinnier' for less bite into the thin air up high or
'fatter' for better high alt performance.
*If someone could elaborate on how to do this...
Q: How do I see the CG boxes for the engine in OPStudio?
A: Edit the properties for the engine and remove the (obhidden) property. Save and reload
the plane. When you are done modifying the CG box for the engine add the property back in
and save. Make sure your engine CG box does not overlap any other CG boxes (the original
planes had a problem with this)
Greg Pringle / Tailslide
Make sure your LODs are centered around the origin (0,0,0)
coordinate when you export them.. the more you have to move the parts once they get into
opstudio the more the FM will change.*
TS
*A note from Snick.... I want to define this a little more
because I didn't understand it until after I did things wrong (even though it had been
told to me)...
When the model is cut into individual LODs, as soon as you cutout
the load select it and move it (in the modeling software) to the coordinates 0,0,0
THEN (and only then) export it as the part you will eventually import into the model.
If you forget to do this on a parent object, and then go back and fix it, you will
have to realign all of the children and their DOFs... Trust me when I say from experience,
this takes time and is frustrating. It can also explain why your airplane doesn't
act quite right. >>> Here is the EXCEPTION <<<
The piece that is the root model of the plane should stay at its modeled coordinates!!!
I would also add, backup often, but include something in the title that tells
you the stated of the plane i.e. PBY-5A(Retro rockets just added).sm
There is no substitute for trial & error!
Printing a copy of this to keep handy at all times! I had forgotten about this !!!!!
Also look here, just a start at another FM tutorial, lots about airfoils and inertia in
OpenPlane:
<http://www.wingswithwires.com/chickencoop/se5a/index.htm>
Q: Why are cylindrical inertia boxes not used more for
the fuselages?
If the fuselage is round (Corsair), I use a cylinder. If it's oblong (Mustang), I use a
box. (You can also use a combination).
3) (Two 3's by the way) You should be able to specify as many tanks as you want for the
engFuelSource.
Q:
What is the modeling coordinate system?
X-axis
goes from left wingtip to right. Y-axis goes from nose to tail. Z-axis goes up and down
through the canopy.
Y is positive from the origin going to the nose. Positive on the X axis is from left to
right. (When looking at the aircraft from behind)
Bryan Russell
Pilot posted 03-23- 11:17 PM
Q: CG reference of an inertia box ?
Is
0,0,0 always assumed to be the physical center of the inertia box or is the origin assumed
to be at one of the corners?
The
inertia volumes are centered around their geometric center, which is the origin of the
part the volume is attached to, offset by the phyCG property. This is only the case
if the 3D modeler draws the object from the center. Depending on the program and the
methods used it can be the corner, the center or somewhere in between. If the 3D program
allows you to select an object and recenter the origin, do so as it makes the Fm work much
easier. See Viewing CG Boxes above
Q: Are the weight of the guns added automatically?
I
was thinking about adding a hidden part with mass properties where the guns in the wings
are mounted to get better weight distribution.
The
weight of the AMMO is figured in, but the guns themselves are "absorbed" by
whatever body part they're in. You can always add a phyLBS property and a phyCylInertia to
them to be sure. Guns are just like other objects, they need inertia volumes defined
to have mass, and therefore weight. See the note about the undocumented ammoBox on the WWW
patch forum. This adds weight according to the number of rounds left for the gun.
Q:Can
you put a tank in each wing and call them both Main for the fuel source?
Probably
not the same name, since the engine will only find the first one it comes across. If you
give them different names (such as MainL and MainR) and list
the names as fuel sources, I believe that the engine will draw from both equally.
=V67=