MiG-9 WIP

[+Timmy 1]

Capun - He's getting all those Max/Min numbers from P1oppy's program. I think it's sensory overload!

I have a question for you FM types - Aside from the Max/Min numbers - you also have collision points. This example from the stock MiG-17s right stab...

 

MinExtentPosition= 0.06,-6.10,1.42

MaxExtentPosition= 1.67,-4.79,1.34

CollisionPoint[001]=1.67,-5.90,1.38

CollisionPoint[002]=1.67,-6.39,1.38

 

Am I correct in assuming that the collision points are what determines if bullets or shells actually hit the aircraft?

If you look at the numbers above, how do you get -6.39 when that is apparently outside the surface of the stabilizer?

I honestly don't understand this process at all. Which is why I have Lexx.

[Lexx_Luthor 57]

I *think* collision points are for player aircraft collision with other objects that have MaxMin extents. Not sure. Or something like that.

 

Collision points seem to be points in space. MaxMin extents form a volume box in space -- I guess each pair of MaxMins when taken together form the classical hit box used in The Sims.

 

I once deleted collision points in some aircraft and found collision with other aircraft was then disabled. And, setting MaxMin volumes to zero on objects also disables collision with that objetct (I did this with the cirrus cloud ships). Not sure if it effects combat hits. I should find out.

Edited September 18, 2007 by Lexx_Luthor

[Guest capun]

Capun - He's getting all those Max/Min numbers from P1oppy's program. I think it's sensory overload!

I have a question for you FM types - Aside from the Max/Min numbers - you also have collision points. This example from the stock MiG-17s right stab...

 

MinExtentPosition= 0.06,-6.10,1.42

MaxExtentPosition= 1.67,-4.79,1.34

CollisionPoint[001]=1.67,-5.90,1.38

CollisionPoint[002]=1.67,-6.39,1.38

 

Am I correct in assuming that the collision points are what determines if bullets or shells actually hit the aircraft?

If you look at the numbers above, how do you get -6.39 when that is apparently outside the surface of the stabilizer?

I honestly don't understand this process at all. Which is why I have Lexx.

 

Simplified Min/Max are your battle damage boxes.

 

Collision Points are used to calculate the plane hitting the ground. For example in a fuselage I would have about 3 points along the Y-Axis in the lowest part (Z-Axis) of the mesh. I have seen some points above the mesh, I guess in case you flip over.

 

You can have a lot of collision points but TK's advise is not to have too many since they all need to be calculated thus taking CPU cycles to do it.

[Lexx_Luthor 57]

Thanks capun.

 

Timmy, I've put all the new MaxMins in the file that had places for them. I'll leave the F-80 collision boxes alone. Next, I want to look at engine thrust altitude tables and fuel consumption. They will need some tweaking with the change out from Column5's J-33 to a pair of RD-20s.

[Lexx_Luthor 57]

Here's a working start for engine table. Over time I can barely get to 14km where I put the ceiling and of course the thrust stops. Yefim offers 13.5km ceiling.

 

AltitudeTableDeltaX=3048.0

AltitudeTableStartX=0.0

AltitudeTableData=1.00,0.80,0.60,0.50,0.40,0.30,0.20,0.10,0.00,0.00

// F-80C ... AltitudeTableData=1.000,0.706,0.491,0.337,0.225,0.169,0.054,0.025,0.000,0.000

 

 

Below, rough shot at MiG-9 fuel consumption in bold. I get rougly 45 minutes of full throttle endurance at about 6km altitude. Range roundabout 650km

 

TSFCM0=1.0

TSFCM1=2.0

//TSFCM0=0.840

//TSFCM1=1.260

MinFuelFlow=0.01

[Lexx_Luthor 57]

Timmy, I got the 260L drop tanks. Something strange...czech it out.

 

It was working just fine with the P-51 tanks, but the MiG tanks are not in the right place. The only thing I changed was P-51 tank to MiG-9 tank. Here, I order wingperson to drop tanks and took a pic. The left tank is far beyond the left wing. The right tank jumps out of the fuselage.

 

 

Did I do something wrong below?

 

//Weapon Stations ---------------------------------------------------------

 

[LeftWingTipStation]

SystemType=WEAPON_STATION

StationID=1

StationGroupID=1

StationType=EXTERNAL

AttachmentPosition=-5.00,1.00,-0.22

AttachmentAngles=0.0,0.0,0.0

LoadLimit=500

AllowedWeaponClass=FT

AttachmentType=Soviet

ModelNodeName=LeftWingPylon

PylonMass=25

PylonDragArea=0.03

FuelTankName=Tank260_MiG9

 

[RightWingTipStation]

SystemType=WEAPON_STATION

StationID=2

StationGroupID=1

StationType=EXTERNAL

AttachmentPosition=5.00,1.00,-0.22

AttachmentAngles=0.0,0.0,0.0

LoadLimit=500

AllowedWeaponClass=FT

AttachmentType=Soviet

ModelNodeName=RightWingPylon

PylonMass=25

PylonDragArea=0.03

FuelTankName=Tank260_MiG9

 

------------------------------------------

 

[AirToAir]

Loadout[01].WeaponType=Tank260_MiG9

Loadout[01].Quantity=1

Loadout[02].WeaponType=Tank260_MiG9

Loadout[02].Quantity=1

[Lexx_Luthor 57]

Same strange results with the Weapon Data section you just sent....

 

[LeftWingTipStation]

SystemType=WEAPON_STATION

StationID=1

StationGroupID=2

StationType=EXTERNAL

AttachmentPosition=-4.75,0.95,-0.25

AttachmentAngles=0.0,0.0,0.0

LoadLimit=1000

AllowedWeaponClass=BOMB,FT

AttachmentType=SOVIET

FuelTankName=Tank260_MiG9

 

[RightWingTipStation]

SystemType=WEAPON_STATION

StationID=2

StationGroupID=2

StationType=EXTERNAL

AttachmentPosition=4.75,0.95,-0.25

AttachmentAngles=0.0,0.0,0.0

LoadLimit=1000

AllowedWeaponClass=BOMB,FT

AttachmentType=SOVIET

FuelTankName=Tank260_MiG9

[+Timmy 1]

I have had no problems of that sort with the tanks. Of course, I'm probably doing something wrong here as it's my first time making a "weapon." The parameters you listed in your last post are the same that I have in my MiG-9 Data file and here is my result:

 

 

You can see the tanks in this shot so I'm not sure what the problem could be.

 

When I made the tanks I centered them in MAX before exporting the LOD. It's possible that I sent you the LOD that I made BEFORE I centered the tanks...

 

I'll send the correct LOD.

 

BTW: I've had a minor malfunction of my Outlook program (I'm assuming co-pilot error as it happened while I was away) and EVERY SINGLE FILE is gone. Would you mind re-sending the MiG files?

Edited September 19, 2007 by Timmy

[Lexx_Luthor 57]

Fun. Timmy, I whited out the Poland skin (need all metal skin), and using repainted Kesselbrut's Yak-3 instrument panel inside your MiG-9 model.

 

The radio mast passes the cockpit USSR test (U See Soviet Radiomast) ... perfect.

 

 

[Lexx_Luthor 57]

Timmy:: [qutoe]When I made the tanks I centered them in MAX before exporting the LOD. It's possible that I sent you the LOD that I made BEFORE I centered the tanks...

hee, that might be it. Thanks.

[Lexx_Luthor 57]

Timmy I got the correct tanks. Thanks.

[laddie 0]

I'm pretty sure it will be as both unpleasant and pleasant to fly as the Jak-15...

 

Sluggish tin-kan but kinda cool...

 

Will prepare a PLAAF skin for this thing :P

[Lexx_Luthor 57]

I'm pretty sure it will be as both unpleasant and pleasant to fly as the Jak-15...

 

Sluggish tin-kan but kinda cool...

 

Will prepare a PLAAF skin for this thing :P

It should be easy to fly, just not a good turning plane.

 

I'm happy with the overall performance -- good speed and high altitude, but the FM "details" I'm looking at now, hopefully starting with simple things like aileron deflection. All the bizzare financial stuff -- CdO , CdS -- or whatever -- I'm not sure about. It will certainly be a "derivative" FM, deriving from Column5's FM in Pasko's F-80.

[Lexx_Luthor 57]

Okay. The speeds are now too high for the altitude performance I look for. I am going to have to learn the lift and drag stuff. I need a sea level takeoff run of maybe 1.2km, 10 minutes to 10km, 900km/hr at 5km, significantly less at sea level and 10km. This will require a proper mixture of thrust, lift, and drag variables.

[+p10ppy 2]

hey Lexx dont know if this is any use or if you already have it (or better sources)

 

Mig-9

OKB figures

Length (ignoring guns) 9.83m

Span 10 m (I-300 but apparently unchanged)

Wing Area 18.2 m2 (I-300 but apparently unchanged)

 

Weight Empty 3420 kg

Fuel weight 1298 kg

Oil weight 35 kg (I-300 but apparently unchanged)

Petrol weight 7 kg (I-300 but apparently unchanged)

Loaded Weight 5054 kg

 

Max Speed

864 km/h at SL

911 km/h at 4500m

 

Climb to 5000m 4.3 min

Climb to 10000m 14.3 min (I-300 not sure if it changed or not)

Service ceiling 13500 m

 

Range 800 km

 

Takeoff run 910 m (I-300 but apparently unchanged)

Landing run 735 m (I-300 but apparently unchanged)

Landing Speed 170 km/h (I-300 but apparently unchanged)

 

source

Mig aircraft since 1937

Bill Gunston and Yefim Gordon

[Lexx_Luthor 57]

Thanks poppy. I have all the dimensions, I think. But how to guess at the lift/drag coefficients and how they vary with altitude, angle of attack, and Mach number.

 

Theorize -- To get off the ground in shorter distance without increasing the sea level thrust (which is okay), I need more lift. That means better CL0 and CLa I think, at least for the wings. Or so I am guessing in an amatuer way. Wow I never thought I'd *ever* get into this. But its kinda neat.

[+p10ppy 2]

Yeah it took me along time to dive in too

But it is fun (if confusing) and I'm strictly amateur

 

Try this if you are interested, (and haven't seen it before ) it helped me a lot with understanding some FE FM bits

I never got up to jets with it tho….

http://www.hq.nasa.gov/office/pao/History/...68/contents.htm

 

this stuff here was very good for estimating CD0 CL0 etc from limited known dimensions/performance…(for the whole airframe)

http://www.hq.nasa.gov/office/pao/History/SP-468/app-c.htm

 

Plugged into FE and it was pretty good at getting you in the ballpark for performance

[Lexx_Luthor 57]

Yeah it took me along time to dive in too

But it is fun (if confusing) and I'm strictly amateur

 

Try this if you are interested, (and haven't seen it before ) it helped me a lot with understanding some FE FM bits

I never got up to jets with it tho….

http://www.hq.nasa.gov/office/pao/History/...68/contents.htm

 

this stuff here was very good for estimating CD0 CL0 etc from limited known dimensions/performance…(for the whole airframe)

http://www.hq.nasa.gov/office/pao/History/SP-468/app-c.htm

 

Plugged into FE and it was pretty good at getting you in the ballpark for performance

Thanks again poppy. Those are interesting reads.

 

For now, I think I'll just hack some coefficients judging what other FMs do -- get a feel for the numbers. All I look for is expected flight performance. The stall and post stall behavior -- flopping around -- does not interest me in a strategic sense, although flopping around is kinda fun I admit.

 

 

Some theory...Column5's F-80 fuselage...

 

 

CD0MachTableNumData=4

CD0MachTableDeltaX=0.40

CD0MachTableStartX=0.00

CD0MachTableData=1.600,1.000,0.928,32.597

 

I guess the vast increase in drag from 0.93 at Mach 1.2 to 32.6 at Mach 1.6 is to create some form of Mach limit. But since the F-80 never exceeds the 0.928 speed bin between Machs 0.8 and 1.2, I don't see how this higher CDO is ever used. I assume the variables follow a straight line between table points.

 

I'd like to take out the artificial MachLimit= variable near the top of the FM file. So maybe creating and tweaking an extreme CDO in the last bin that the aircraft can reach would work. Would this be correct thinking?

[Lexx_Luthor 57]

Or, is the standalone MachLimit= primarily for almost transonic aircraft, where effects unique to approaching the sound speed may not modelled in the game? I mean, would the MachLimit= be needed for very slow prop planes or very fast Mach 2 planes? Well beyond the speed of sound, either above or below, can't thrust and drag values be tweaked to get the right rough max speeds?

[Lexx_Luthor 57]

Okay, I'm gutting the F-80C flight model of moment variables and tables, and figuring out what each do and what I need with suitable values.

 

Question:: The Alpha dependent variables all seem to be related to controls. What I'd like to do is something like the snaking of the MiG-15 above M=0.8, no matter if any inputs are created by the pilot. Is there something that would work that is Mach related, not Alpha related?

[Lexx_Luthor 57]

pffft this is easy.

 

...after pulling my own teeth out.

 

I went through the F-80 file and tested all the C variables to see what they do. I'm making my own now, deleting lots of variables that seem too subtle to be worth worrying about in order to simplify the thing. Variables that I think could be useful later I left as zero. Playing with Xac tables are next I guess. Its working great but then I must tweak everything to match MiG-9 flight performance.

[Lexx_Luthor 57]

Xac tables I am made mostly constant for now. If I want to create some Mach related pitch instability, I can make the Xac vary.

 

I made some wing stall variables that, in combination with elevator variables, gives a safe but nauseating stall. Yefim says the MiG had a combination of airfoils along the span that prevented spinning from stall. Or so I figure.

 

Right now, takeoff is good. Climb is too high -- thrust/altitude table needs work. Need more energy bleed in turns I think. Induced drag variables might handle that.

 

With suitable drag tables, I *think* I eliminated the artificial MachLimit. Not sure. Testing with MachLimit=25.0 shows I am limited to about Mach 0.8 no matter what, getting nowhere near Mach 25.

[Lexx_Luthor 57]

Nap, I am going to need the MachLimit. Thrust and drag variables can help limit level top speeds, but not dive speeds. For that I will need the artificial limit. However, this may be needed only for aircraft that failed to cross the speed of sound in a dive. Just a guess.

[Lexx_Luthor 57]

What? MachLimit does not seem to work well for limiting dive speed here. I may have to do a detailed CD0 (drag) Mach table, just for Fuselage, to do this one thing. I think I can have the drag value jump almost vertically at the correct Mach. That should limit dive speed, I think.

[Lexx_Luthor 57]

 

With the experimental setup below, at 5km I max out at Mach 0.81, about 930km/hr TAS which is close (Yefim - "920"). In a dive, I can only get to Mach 0.85.

 

I have MachLimit=25 ... or infinity...no matter, the steep rise in drag in the last data bin keeps airspeed in check.

 

[Fuselage]

:

:

CD0MachTableNumData=10

CD0MachTableDeltaX=0.1

CD0MachTableStartX=0

CD0MachTableData=1,1,1,1,1,1,1,1,1,10

:

: