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Dangerousdave26
November 19th, 2009, 20:09
For my first attempt at creating flight dynamics I thought I would mess around with the FS2004 Pander S.4 Panderjager so far I have taught myself a lot and I am happy with it but...

I collected data from as many sources as I could and for values I could not come up with real world numbers I did the next best thing. I looked at other similar aircraft from that period. I did not copy those values as much as I applied some SWAG to them.

For reference here is the real world data I collected.



<from various sites>
3 Wright Whirlwind R-975-E2 engines, 420 hp each.
Length 12.5 meters, 41.0 feet
span 16.6 meters, 54.4 feet
height 2.9 meters. 7.5 feet
Wing area: 46 sq. meters 150.9 feet
Empty weight: 3,441 Kilo's, 7 586.1 lbs
MTOW 5,736 kilo's, 12 645.7 lbs
Max speed 360 kmh, 223.7 mph, 194.4 kts
cruise speed 300 kmh, 186.4 mph, 162 kts
Landing speed 120 kmh, 74.6 mph, 64.8 kts
Ceiling 5,400 meters 17,716.5 feet
Range 2,950 kilometers, 1,833.0 miles, 1,592.9 nm

R-975E-3: 420 hp (313 kW) @ 2,200 RPM up to 1,400 ft (427 m), 450 hp (336 kW) @ 2,250 RPM for takeoff. Increased supercharging, slightly higher compression ratio.

Propeller diameter: 2.85 m,
Propeller surface: 6.38 m
Climb rate 7.6 m/s,
Maximum speed at ground level: 342 km/h, 212 mph, 184.7 kts

<from a German site translated by yahoo>

echnical data: Pander S.IV Panderjager
Use: Long-distance post office airplane
Year of construction: 1933
Crew: 2-3 men
Engine: three air-cooled 9 cylinders radial engines WRIGHT R-975-E2 Whirwind with three-sheet variable-pitch propeller
Take-off power: 420 HP (310 KW)
Continuous duty: 395 HP in 4.000 m (292 KW)
Span: 16.60 m
Length: 12.50 m
largest height: 3.30 m
Propeller diameter: 2.85 m
Propeller surface: 6.38 m
Track width: 5.28 m
Wing area: 46.10 m
V-type: +5
Empty mass: 3,210 kg
Takeoff weight normally: 5,150 kg
Takeoff weight maximally: 5,700 kg
Level of fuel in the tank: 1,090 litres
Surface loading: 123,6 kg/m
Power loading: 4,52 kg/PS (6.12 kg/kW)
Maximum speed at ground level: 342 km/h
Maximum speed in 4.000m: 364 km/h
Cruising speed in 4.000m: 300km/h
Ceiling: 6,050 m
Climbing achievement: 7.6 m/s
Climbing time on 1.000 m: 2.25 min
Climbing time on 4.000 m: 9.5 min
Range normally: 1,850 km
Range maximally: 3,240 km
Flight duration: 11 h
Armament: none
This information from the German site was the best it gave more detail.

Here is the problem

I can not get the prop speed up to the rated 2250 rpm. The Prop turns at 1,300 (about) RPM. Much like a Wings of Power aircraft this one preforms better with the prop pulled back to 75% than it does the prop full forward. That translates into about 1000 rpm.

The problem this causes is it takes a lot of runway to get off the ground at 100% prop. Almost all of a 9,000' runway. Now if you pull the prop back it takes off almost like I would expect it to if it were running at 2250 RPM.

I have been reading the Aircraft Container manual but it has not provided me any in site.

So even with this problem I have corrected the contact points, center of gravity, brakes, weight issue and if i get the prop fixed I have the speed and range issues figured out.

Something tells me that once I get the prop turning 2200 rpm that will blow all my speed and range numbers. :icon_lol:

Anyway so far it has been an enjoyable experience.

Any help is greatly appreciated

Dave

fliger747
November 20th, 2009, 08:57
Typically large piston aircraft engines had a gear ratio somewhere near two, such that the prop turned at about half the engine speed. Are you using AFSD to check out the prop and engine speeds and thrust values? For a very early aircraft prop RPM (not engine) speeds around 1000-1200 RPM would be appropriate.

If you are developing the appropriate engine HP values check the thrust and see if an issue resides in the prop tables.

Good luck! T

Dangerousdave26
November 20th, 2009, 13:36
Thanks Tom

I was looking at FSDat and not AFSD.

I also could not read the gauges in the aircraft and did not take the time to install a panel that would give me a gauge to read.

Stupid me! I knew it had a gear reduction box, I knew the ratio was 1.67 originally in the aircraft.cfg but I failed to realize what that means.

I changed the ratio to 1.80 to bring the prop speed down to 1200 RPM works like a charm.

Thrust is still in the works its good but not perfect.

sparks
November 20th, 2009, 16:44
I wasn't sure what you started with for flight dyanmics on this model, so I went directly to flightsim.com and downloaded it. I found an unfinished flight model that was very difficult to work with. The contact points were particularly messy and FS9 was crashing until I added more points than just the landing gear.

As far as problems with the engine tuning is concerned, the overall aircraft performance numbers have to be reasonable. Prop gear ratio is not that important - it's only important for matching a prop rpm gauge to an engine rpm gauge.

When you have a constant speed prop and engine RPM doesn't reach the rated max, the problem is usually caused by the prop tables. AirWrench tries to match the prop tables to the engines max rated power for climb, max speed at sea level and at critical altitude using the specs for climb rate, and speeds. The optimum climb speed, climb rate, and WEIGHT used to calculate climb rate all factor into the prop table calculations. If the numbers aren't realistic, the resulting prop table coefficients can cause the engine to 'lug' under certain situations and never reach the rated RPM.

I realize this is all pretty general and may be hard to put into practice, so if it helps, here's a link to what I came up with this evening given the specs listed for this aircraft:

http://www.mudpond.org/Panderjager.zip (http://www.mudpond.org/Panderjager.zip)

aeromed202
November 20th, 2009, 17:12
Are you making dynamics from scratch? I only know something about editing cfg's after they are made.

I would just add that as a self-taught cfg fidgeter, with some good results by all accounts, I don't get too hung up on believing that the cfg values were arrived at by meticulous attention to real-world data, unless you are making the aircraft yourself. By that I mean that for any complete aircraft I don't know how the cfg values were obtained as I don't know how to make them. By by trial and error I can see what effect my edits have and from one plane to the next, scales of response will be different. I am working by feeling around in the dark so-to-speak. One makers idea of yaw MOI will be 1400 and a similar model by another maker may be 10000. So I just edit to effect and let the numbers be as they may.

Just my two cents.

Dangerousdave26
November 20th, 2009, 19:06
I wasn't sure what you started with for flight dyanmics on this model, so I went directly to flightsim.com and downloaded it. I found an unfinished flight model that was very difficult to work with. The contact points were particularly messy and FS9 was crashing until I added more points than just the landing gear.

As far as problems with the engine tuning is concerned, the overall aircraft performance numbers have to be reasonable. Prop gear ratio is not that important - it's only important for matching a prop rpm gauge to an engine rpm gauge.

When you have a constant speed prop and engine RPM doesn't reach the rated max, the problem is usually caused by the prop tables. AirWrench tries to match the prop tables to the engines max rated power for climb, max speed at sea level and at critical altitude using the specs for climb rate, and speeds. The optimum climb speed, climb rate, and WEIGHT used to calculate climb rate all factor into the prop table calculations. If the numbers aren't realistic, the resulting prop table coefficients can cause the engine to 'lug' under certain situations and never reach the rated RPM.

I realize this is all pretty general and may be hard to put into practice, so if it helps, here's a link to what I came up with this evening given the specs listed for this aircraft:

http://www.mudpond.org/Panderjager.zip (http://www.mudpond.org/Panderjager.zip)


Great stuff to know

This means I need to add the pay load section to my cfg because this could cause even more concerns.

I am still going to work with my air file / cfg but I would like to know if you have any objections to me using your contact points skid points to be more specific. I have not had time to look into setting those up.




Just my two cents.

And well worth it. :ernae:

One thing that I know is you can not duplicate every thing in FS...

You can only come close... (I think I am quoting Tom there)

And close is defined by the person working on the project.

The question then becomes when do you say close is close enough. :isadizzy:

When you are happy. :monkies:

sparks
November 20th, 2009, 21:17
Are you making dynamics from scratch?

Yes, I did the air file I linked to from scratch using AirWrench. I wrote AirWrench, and I also develop flight dynamics for commercial products.

FS will do a very reasonable simulation if it's given accurate data in the cfg and air files. The sim is basically a number cruncher that uses equations drawn from aerodynamic engineering texts. It's not black magic - it's based on solid engineering, physics and math.

The physical data contained in the aircraft.cfg is very important. The weight is probably the most important parameter - it's used in motion calculations in every linear direction. (Physics 101: f=ma) The span, area and chord of the main wing are also particularly important because these parameters appear in all the lift and control equations.

MS suggests the following equations to estimate MOI:

MOI = EmptyWeight * (D^2 / K)

Where: Pitch Roll Yaw
D = Length Wingspan 0.5*(Length+Wingspan)
K = 810 1870 770

(sorry about the poorly formatted table - thanks html)

You can't get the most out of FS without building your own air file. You can't make C172 into a C-130 just by changing the aircraft.cfg file. ;)

sparks
November 20th, 2009, 21:27
The question then becomes when do you say close is close enough.


If you can't tell the difference, it's close enough for all practical purposes. :rolleyes:

sparks
November 21st, 2009, 06:04
I am still going to work with my air file / cfg but I would like to know if you have any objections to me using your contact points skid points to be more specific. I have not had time to look into setting those up.



No objections at all. I put it up on my website and posted the URL so it's available for use as-is, to modify and refine, or just examine for your own edification.

Ivan
February 16th, 2010, 03:47
Hi Sparks,
I was reading through the "Propellers" document (very educational!) on your site but didn't see a mention of what causes a propeller to "lug". I figure it has to be some relationship between the power coefficient and the graphs in table 512. What is the relationship that would limit the speed of the propeller / engine speed?

Thanks.
- Ivan.

fliger747
February 23rd, 2010, 15:52
Jerry's Original work book (Excell) approach is a good one. His Airwrench product has continually evolved into a fine tool with many twek adjustments available and some good graphic presentations of the derived aircraft parameters.

Well worth the cost of a decent bottle of wine....

T

Ivan
February 24th, 2010, 17:03
Hi Flieger747,

I believe much more in understanding what is going on rather than finding the tool to address the issue. I am sure FDWB and AirWrench are great tools, but I am more interested in understanding basic principles. That is why I am also flipping through quite a few old NACA reports that peripherally address this issue. There are a lot of terms mentioned such as Torque Coefficient that I just don't have a "feel" for yet. I've already put together a couple simple spreadsheets for Advance Ratio and Power Coefficient that let me tweak the numbers and see the changes so that I can get a "feel" for what these numbers are describing.

Thanks.
- Ivan.

sparks
February 25th, 2010, 16:50
Hi Sparks,
I was reading through the "Propellers" document (very educational!) on your site but didn't see a mention of what causes a propeller to "lug". I figure it has to be some relationship between the power coefficient and the graphs in table 512. What is the relationship that would limit the speed of the propeller / engine speed?

Thanks.
- Ivan.

The propeller power coeffecient equation is:

Cp = 550 * hp / (rho * rps^3 * diam^5)

The propeller will 'lug' if the value of Cp for a given advance ratio and blade angle is less than what is in the propeller table (511).

Ivan
February 27th, 2010, 17:20
Hi Sparks,

I was figuring there would be some kind of internal calculation (not lookup table) that gave the torque required by the propeller at the current angle, rpm and advance ratio (need a formula for that also) which would be compared with the available engine torque at the current rpm. If engine torque was higher, the excess torque would be applied to accelerate the propeller against the inertia value specified in prop record. If the engine torque were lower, the rpm decreases by the same calculation.

I know the Coefficient of Power uses many of the same values that would be used to calculate torque, but how can that alone be sufficient to calculate the rate of increase or decrease in rpm? I am guessing that a torque calculation is hidden between records 511 and 512 in combination with the advance ratio but I just can't see it.

Thanks.
- Ivan.

napamule
March 17th, 2010, 19:07
Ivan,
You do it the way I do it (well, 'simular'). My question is: have you tried changing the prop length and then also adjusting the prop_moi value and trial & error those 2 values? I haven't. Just curious.

You look at cfg and wonder what you have there that you don't have in the air file. No matter, as cfg will over ride the air file. But success depends on 'adopting' FDEs to the MODEL. This is the secret to success when making changes to cfg / air file to get improvemtns.
CB
Napamule

Milton Shupe
March 17th, 2010, 19:51
Ivan,

Sometimes tools help improve understanding. At least it helped me to see by tables and graphics, and calcs how the interactions work among the air file tables. The FDWB was immensly helpful in taht regard.

MaddogK
March 18th, 2010, 07:41
I've been messing with my prop tables last couple days simply to boost the high altitude performance (ALL other altitude/speeds are 'spot on') but I found the higher I push the power coefficient for the shown beta in AFSD at my max altitude(i.e. beta 21.6), the more the sim wants to use a lower beta value after the edit. It feels like I don't have enough motor at high altitude to get the prop to work properly and I don't want to mess with the engine power as it undoubtedly effect the lower altitude performance. Is there a turbo boost curve I can alter ? Is FDWB still available for D/L ?

MaddogK
March 18th, 2010, 16:03
Never mind, found my copy on my 'other' computer, too bad there's no import function as the next couple weeks are gonna be spent on entering data into the spreadsheet.

Heh, also found my MDL disassembler, that might come in handy.

fliger747
March 18th, 2010, 17:23
Are you using AFSD to check out all of the parameters? You can see how MP and HP change with altitude and observe prop RPM and pitch angle. It is possible that you are reaching a pitch limit specified in the Cfg file?

The "Critical altitude" entry will affect how high max HP is available with a super/turbo charged engine.

Cheers: T

MaddogK
March 18th, 2010, 19:59
Are you using AFSD to check out all of the parameters? You can see how MP and HP change with altitude and observe prop RPM and pitch angle. It is possible that you are reaching a pitch limit specified in the Cfg file?

The &quot;Critical altitude&quot; entry will affect how high max HP is available with a super/turbo charged engine.

Cheers: T

Yes AFSD is my viewer, and it's saying as I push up the efficiency curves @ beta 21.6 and 23 my HP decreases unless I pull prop RPM down to regain the .89 efficiency number, if I leave prop PRM the same as my previous test (lower numbers in sec 512- hi end of beta 21.6 and 23 graph) my airspeed decreases until I eventually stall. I could extend the beta range from 9-23 to 10-60 (another authors FM for the same A/C) but the A/C is on steroids- 50-70 kts too fast at ALL altitudes. Even when I use the slower A/C cfg file with the faster air file the A/C is too WAY to fast so I'm pretty sure these prop curves are the cause.

fliger747
March 19th, 2010, 10:09
The way I work... is like some politicos. If I have a prop table that is pretty close and my HP vrs Altitude curves as right as I can get, then I will adjust the CDO drag value in the Primary aerodynamics tab in the .AIR file to get the proper airspeeds. If the CDO value is a reasonable one then everything is good under the heavens, or about as good as it will get.

Props vrs airspeed and RPM can be a bit interesting, even for constant speed versions. They will be optimized for a particular airspeed, altidude and advance ratio depending on the type of aircraft. Also it should be noted that the prop is connected to an aero engine which may or may not put out it's maximum torque or horsepower at mximum RPM. The R2800 C series gained a couple of hundred HP over the B series through improvement of the oil scavenging system, reducing the HP list internally from splashing oil around!

The addon Aircraft Airfile Manager is a good utility as you can see every one of the prop tables as a series of curves which are easy to edit.

Cheers: T

MaddogK
March 19th, 2010, 11:30
As I understand it, drag is a 'number' used in calculations and not a curve. So if I alter drag to achieve hi altitude speed lower altitude speeds are going to change (which is what I'm trying to avoid). I did find the prop beta range in FDWB so I can alter the calculation range the workbook is cooking up, so back to the labs tonight. I actually do all my editing in aired while reading the data from AAM, save the edits from aired then reload the model into airwrench to see what it comes up with. Airwrench has crippled many A/C simply by turning on the edit function and making NO changes, so I'm afraid to use it.

fliger747
March 19th, 2010, 19:53
MK:

Drag is indeed a number, however the absolute value varies with the air density. For WWII fighters (and I ahve done a bunch of them), if I get the SL: and critical altitude HP values right, usually the SL and critical altitude TAS values will be very close if I adjust the drag to fit either.

Yes Airwrench does a complete search and destroy with the entered values. Usually Jerry's utility does a very good job on calculating prop parameters. Ya can steal them from a dummy airfile if you want to do that and paste them into your handmade file.

Cheers: T

MaddogK
March 20th, 2010, 16:10
Thanks Fliger, thats exactly what I did. FDWB gave me a 'limp' version of what I already had, but I took the FDWB generated sec 511 and 512 tables and inserted them into the original air files and presto- about 14 kts more top speed at 21k ft. As I compare the original tables with FDWB's tables I see an identical sec.512, but 511 has all the curves starting .5 below the originals. Seems lower power coefficients work better than higher efficiency numbers. Still alot of testing to go, but I think I may be on the right track. My beta has stabilized right around 16 instead of the original 20 or so, and the prop is turning 2100 instead of 1600 to get that speed. Still alot to learn, but I'm getting closer to what was published.

fliger747
March 21st, 2010, 10:13
Just curious: What CDO number are you using and what sort of plane?

T

fliger747
March 21st, 2010, 16:11
A slick plane like a Spitfire might havce a CDO somewher around 30. A fairly draggy plane perhaps 50. Just from a look? 38-41 might be in the ballpark.

Cheers: T

MaddogK
March 22nd, 2010, 15:17
At max alt (21k) and max weight (10300), max speed (105 kias/145 TAS) CDo is .028, CD is .0479, l/d 12.48, cdp is .0364. This is Alex Nicolsons FM for Amelia Earharts FSDB Lockheed Electra L-10E, with my new prop tables. The old tables netted about 90 KIAS, the orig FSDB tables got in the 125ish range.

fliger747
March 24th, 2010, 00:15
Did this plane have a real constant speed prop or adjustable ones lik the early Spitfire ones which could have two pitch angle selected. A CDO of .28 seems pretty low.

Cheers: T

MaddogK
March 24th, 2010, 06:35
According to Lockheeds docs it was equipped with a fixxed prop (1:1 ratio) but a constant speed prop was offered as an option. This model is equipped with the constand speed variety with a beta range of 9-23. The FSDB model came with a range of 12-40 IIRC.

Ivan
April 5th, 2010, 12:40
Hello Folks,

Didn't think anything was really happening in this thread, so I missed the last few weeks of discussion.

Napamule,
The problem here is that I am actually still tweaking AIR files for CFS1. There aren't any useful variables in the CFG file.

Mr. Shupe,
I don't disagree with the tools helping understanding, but in this case, I was working on an "AIR" file for a ground vehicle, so a basic understanding of the relationships and calculations was all I was looking for. There really ISN'T a real world match to what I am doing. As it turns out, I pretty much got the effect I was looking for except for the engine lugging. I would like to set up a reverse thrust deal, but don't know enough to do it or even whether it is possible in CFS.

MaddogK, Fliger747,
I only mess with CFS flight models, so newer versions may have different tweaks, but here goes:
There IS a supercharger / turbo charger boost setting which can be tuned for better high altitude performance. Even the effect of that boost setting can be altered slightly by adjusting the torque percentages at each RPM and the Friction loss at each RPM. I use it to bring the engine power UP at medium altitudes and reduce power to bring the service ceiling down. It has worked the couple times I have tried it. I currently have a Ki-61-Ic that has a service ceiling just over 40,000 feet that needs this treatment.

Besides the standard CD0, there is also the Mach Drag tables which can be used rather creatively. I use it to limit the terminal velocity for planes I build, but it is just a value for each speed range up to about Mach 3.2, so you can change the lower values and leave the upper values at zero if you wish to add some drag at the lower speed ranges. I use it to create a Sound Barrier and then have the values past Mach 1 slightly lower but high enough so that there isn't enough thrust even in a power dive to make the plane go faster.

Hope this helps.
- Ivan.

fliger747
April 5th, 2010, 12:52
For the plane he was working on there was a negligible mach effect, however with faster WWII aircraft, capable of infringing on the transonic area, it is possible to adjust the mach drag values. More importantly the mach pitch effects can also be adjusted as well as loss of control effectiveness.

Most planes do not achieve max altitude at maximum weight! For example thre max certified altitude on the 747-400 is 45,100 feet. I have had it up to FL 450 on a number of ocassions, but you have to be pretty light. At max weight (about 870,000 lbs) the low thirties is about max.

Cheers: T

Ivan
April 6th, 2010, 10:00
Hi Fliger747,
I agree with you that the Lockheed Electra didn't REALLY have to contend with Mach effects. I was just describing how the Mach Drag tables can be used to create arbitrary non-linear drag through the speed range. In fact, I used the Mach Drag to limit the terminal velocity of a Fokker E.III Eindecker to around 200 mph which is no where close to Transonic. It is also how I am limiting the dive speed of a A6M2 Zero. The plane has structural limitations which can not be implemented in CFS1.

- Ivan.


Supercharger Settings:
[505]
9=34,BOOL,Turbo/Supercharged
10=38,double,Manifold Pressure Max (in)
11=40,double,*Supercharger Low Altitude Boost Related ?
11h=Usually 1.0000 if Turbocharged|Large values (~100000) Inc MP/HP at SL
12=48,double,*Boost Gain
12h=Maximum MP/Ambient Air Pressure|Sets max speed/max altitude factor

The two tables below allow adjustments for service ceiling. This may not be the right way to do it, but it seems to have the effects I am looking for.
[508]
1=00,int32,No. of Table Pairs
2=04,double,RPM 1
3=0C,double,Torque Fact 1
4=14,double,RPM 2
5=1C,double,Torque Fact 2
6=24,double,RPM 3
7=2C,double,Torque Fact 3
8=34,double,RPM 4
9=3C,double,Torque Fact 4
10=44,double,RPM 5
11=4C,double,Torque Fact 5

[509]
1=00,int32,No. of Table Pairs
2=04,double,RPM 1
3=0C,double,Torque 1 (ft-lb)
4=14,double,RPM 2
5=1C,double,Torque 2 (ft-lb)
6=24,double,RPM 3
7=2C,double,Torque 3 (ft-lb)
8=34,double,RPM 4
9=3C,double,Torque 4 (ft-lb)

MaddogK
April 6th, 2010, 15:41
Thanks Ivan (Nice to see you again), will give it a look, as the 'official' Lockheed certified docs state " Airplane performance @ full gross weight" 10100 lbs, service ceiling=21,150 ft, absolute ceiling=23,200, simply NOT achievable with the updated FM, but the original FM is overkill (near 25k ft) so all I wanted to do is increase the updated FM ceiling a bit as it's barely achievable EMPTY but the lower alt speeds are nearly spot on. To clarify I'm trying to get somewhere between two Fm's created by other peeps. So far with the prop table edits I've gotten the FM ceiling 21,100 @ 115 KIAS (somewhere in between the other 2) so I cant complain- it's BETTER. Still have to compare the published data (210 MPH @ 5000 ft) with my edits, but the data is from the L-10A, not the 10E with bigger engines, my tests shows about 10% faster as I think it should be so I'm content with it as-is. May have to play with fuel consumption a bit as it seems a tad low tho.

Ivan
April 6th, 2010, 17:21
Hi MaddogK,
It sounds to me like you would want to increase the value for "Boost Gain" for record 505. Try small increases. A little goes a long way. Do you also have a "Full throttle height" for the aircraft? What altitude does it achieve maximum speed? Just changing the "Boost Gain" doesn't affect low level performance at all.

What I generally do when trying to tune altitude performance is to set the aircraft on autopilot to maintain altitude and warp it to various altitudes and note the engine power. From this VERY quick check, you can pretty much figure out where the maximum speed will be achieved and after one max ceiling climb test, you can figure out what power is required at the ceiling. (Note the fuel load because it is the one factor that is constantly changing.) You can then adjust boost to get the same power output at the new altitude you want to be the new ceiling. It isn't perfectly precise, but gets you there pretty quick.

I am also trying to affect fuel consumption in a CFS1 aircraft (B-25C) but am not sure how. The value that is labeled Fuel Flow Scalar seems to do nothing, and I don't have a value in a CFG file to tweak. If anyone here has some insight, please let me know.

- Ivan.

fliger747
April 7th, 2010, 15:05
CFS1! I remember being pretty impressed because it had 3 D terrain!

Good luck! T

Ivan
April 7th, 2010, 17:45
Hi Fliger747,

3D terrain is fun! I find that I crash into it a lot. =-)
Actually what might be even more scary is that I still do most of my development on a Pentium 233 MMX. Every other computer in the house is faster including this laptop I am using for Internet access, but the old Pentium is sufficient. I have installations of CFS2, CFS3, IL2, and a bunch of non-shooters, but I find I really only stay with CFS.

Originally I started building planes for CFS to prove that a decent looking plane could be built within the limitations of AF99 and Aircraft Animator. I believe I have pretty much hit the limit of what can be accomplished with these tools. IMHO, the B-25C looks pretty fair. I have seen a couple payware B-25s that have much more detail but the basic shapes are not right.

Check out a couple screenshots here:
http://www.sim-outhouse.com/sohforums/showthread.php?t=27511&page=4

- Ivan.