Conspicuous by Their Absence

[Ivan]

The idea is that the two shots are measured (at the center of the bullet hole) and the number is recorded.

Perhaps I should have phrased this differently. I seem to have left out a few words.
In the group, the two shots FURTHEST APART are measured.....

Hello Womble55,

I also have a fair amount of experience with Lee Enfields and have owned a few. I have never gotten sub-MOA accuracy out of any of them though the No.4 Mk.I* and a No.1 Mk.III* have been pretty respectable with 1.25 inch groups for 5 shots at 100 yards. The FAL was pretty comparable with good ammunition though there were hints it might do better but the scope mount and front sling swivel didn't look conducive to accuracy.

If your guys were hitting well under 1 MOA at 300 yards with iron sights, you should have come over to this side of the pond and shot at the National Matches at Camp Perry. Consistent groups of that kind are enough to shoot clean scores and win the matches with a pretty high X count as well.
My own scores are not nearly so good. At Prone and Sitting, I was getting scores in the Mid 90s and for Offhand, I was typically getting scores only in the 70s. I wasn't anywhere near steady at standing.

- Ivan.

 

[womble55]

We only ever shot prone and the grouping was after many attempts at the RAF marksman badge, shamefully I only ever did it the once as that was enough to get the badge and requalification wasn't required.
I loved the Lee Enfield, it looked right, felt right and because of the years of care smelt right.
We only ever used standard military issue rounds, no special preparation or anything like that. We were typically given two five round clips, loaded the magazine and shot.
If we were trying for our marksmanship badges we would have a spotter and advice from a senior NCO or Officer during the day and could fire up to fifty rounds a day.
I believe my hearing problems nowadays is because of the number of rounds fired without ear protection....Happy Days EH?
Lets get back to the subject in hand and what we would like to see in CFS1

 

[Ivan]

Lee Enfield

I kinda like Lee Enfields. They were my first "High Power" (in American, this means centerfire) rifles.
Decades ago, they were inexpensive and plentiful. .303 British isn't the easiest cartridge to reload though.

Now on to the CFS Part:
I can't seem to pin down why the last P-38 Flight Model I did back around 2000 or 2001 has a pretty consistent engine failure.
So, instead of tuning the old version, I thought it would be a good idea to build a new one. Perhaps I will do a comparison later.

So far, the results are that HP is about right for Sea Level and Critical Altitude.
Between that, the numbers are pretty far off.

Performance is:
1415 HP @ 500 ft for 340 mph.
1477 HP @ 25,000 ft for 422 mph.
Maximum speed is actually 428 mph @ 22,500 ft.
Service Ceiling with 1/2 fuel is pretty near 41,000 ft.

There is plenty more to tune after that.

- Ivan.

 

[Wayland]

Re: Lee-Enfield

George MacDonald Fraser (of "Flashman" fame) penned a wonderful segment in his WWII memoir, "Quartered Safe Out Here". He served with the Border Regiment in Burma in 1945 and carried a Mk III 'til he made Lance-Corporal and had to carry a Thompson. It's an excellent read loaded with his trademark snarky humor.

Steve

 

[Ivan]

Long Live the Short, Magazine, Lee-Enfield!

Hello Wayland,

The SMLE or No.1 Mk.III is one I know pretty well.
I just came across a box of spare parts for the No.1 Mk.III* last week.
I had bought three brand new bolt bodies made for the Australian guns, several bolt heads and other assorted parts in attempt to fit a new barrel.
The pieces came from all over but I did find a combination that fit together with perfect headspace which nearly impossible to find in a service Lee Enfield.
I also had two unused brand new bolt bodies, firing pins, extra bolt heads and some other left over pieces which I just put in a box and left on a shelf afterwards.

- Ivan.

 

[Ivan]

Some Aircraft seem to be much easier to fly than others when doing low level high speed passes. One of the nice things about opposite rotation of the engines is that there is no noticeable lateral or directional trim changes. There is also quite a lot more acceleration.

Did lots more tuning on the P-38J. Some of these edits were quite radical and I am still not all that close to final yet.

One of the funniest things I encountered was braking too hard and flipping (!) the aeroplane.
That wasn't hard to fix, but it was an interesting surprise to flip an aeroplane with a nose wheel.

The Flight model I was working on had three fuel tanks per side:
A 90 Gallon Main Tank behind the main spar of the wing.
A 60 Gallon Reserve Tank ahead of the main spar.
A 55 Gallon Tank in the leading edge of each wing outboard of the engines.

I came across an earlier version of the AIR file (from about 2000 or so) and noted that the model I was trying to build was a P-38J-10.

The early models of the P-38, without the chin scoops, had their intercoolers built into the outboard leading edge of each wing.
This was quite an inefficient setup with the supercharger in the middle of each boom piping charge air out to the wing tips before it went into the engine.
The leading edge intercoolers were efficient for streamlining, but also didn't cool the air that well before it went into the engine. This was the main limitation to running the engines at higher power settings before detonation would start.
With the J model, the intercoolers were moved under the engines next to the oil coolers. That greatly increased the maximum speed because although the airframe drag was higher, the engine power was much higher.

At some point, fuel tanks were installed where the intercoolers were, but those fuel tanks were not present in the J-10 model.

Another feature that was not present in the early J models was the dive brake under each wing to aid recovery in a high speed dive. In trying to add in some compressibility effects, I tried quite a few high speed dives starting from around 35000 feet altitude. Many of them ended up as crashes because elevator effectiveness at very high speeds is greatly reduced and the P-38 gains speed in a dive VERY quickly and ghe maximum diving speed is very low. In fact the limit (460 mph IAS at low altitude) is about the same as for a late model Japanese Zero but for very different reasons. (At high altitude it is only 420 mph IAS.)

This is one of the parts I really like about flight sims: Reading about compressibility effects and dive limitations is interesting, but actually "experiencing" and being able to experiment with the effects gives a much better appreciation of how things worked.
Perhaps this is a bit circular because we try to program in the documented behaviour and then test for the same behaviour.

Current Performance:
1417 HP @ 500 ft for 344 mph
1477 HP @ 25,000 ft for 421 mph
Actual Maximum speed is 427 mph @ 22,500 ft
Service Ceiling was not tested but should be considerably higher with a bit more engine power and less fuel.

Lots more left to tune. Hopefully I can figure some of it out.

- Ivan.

 

[Ivan]

Braking Factor

Sometimes something sits right before your eyes and has hints that it might not be what people tell you it is....
(Advance Warning: I am gonna get VERY long-winded here.)

The Background:
A few days ago, I was very surprised when I came in for a rather hot landing in the P-38J.
I had lined it up after wobbling all over the place and finally had it centered on the runway.
When I applied brakes, the aeroplane flipped. Imagine my surprise at having a nosewheel aeroplane flip!

That is not sposta happen, but the P-38 is an interesting combination:
It has a fair amount of weight on the nosewheel unlike most aeroplanes with a tricycle gear.
It also has a CoG that is fairly high: Almost even with the Engine Thrust Line which is where I set it for thie visual model and AIR File.

Fixing it was pretty easy.
The Braking Factor is a 16 bit Integer as described in both AirEd and FDE config files.
Maximum value is 32,767 and Minimum value would be -32768.

I have entries in my notebook from testing many years ago that Positive values seem to prevent the aeroplane from planting its nose into the runway when braking too harshly.

I had therefore made it a habit to use negative values so that if the pilot goofed, it aeroplane would oblige by sitting on its propeller. I also had noted that there didn't seem to be much variation when using negative values, but that very low negative values had too harsh braking and would flip too easily.

I reset the P-38J's brakes to a reasonable positive number that reduced speed pretty well but didn't cause the aeroplane to "hop" much when slowing down.

This Evening's Events:
Since I am working on a P-38J AIR File and do testing and archiving on several different machines, I can seriously alter the AIR file on my test machine without regard for accidentally damaging my working copy of any particular AIR File.
The P-38J was the perfect subject for testing because it does not pull to either side on the take-off run.
It will track straight under full power acceleration unlike any other CFS aircraft I have encountered.

I was not satisfield with what I had in my notes from earlier testing of negative values; They seemed way too similar.
I needed to be able to test full braking to quantify it but without being able to flip the aeroplane.
First corruption of the AIR file was to move the nosewheel contact point from 100 inches ahead of the CoG to 200 inches ahead.
The aeroplane pitched a bit on the take-off run but was controllable otherwise. It also no longer flipped.

First test was to see what effect the positive values actually had and do it in such a way that I could quantify it in my notebook.
It could be seen fairly quickly that low values had nearly no effect and high values braked faster but cause the aeroplane to hop.
From 0 - 32,767, I had already chosen to use 22.000 for fairly good braking but with very little hopping.
Results were as expected and very predictable though I won't claim that the effect is linear. There is a much greater observable difference between 500 and 10,000 than between 22,000 and 32,767.

Second test was for negative values. The extremes at -1 and -32,768 all seemed too harsh with the wheels hopping but neither value would flip the aeroplane thanks to my extended nose wheel.
-1 seemed to brake quicker but I could not tell by how much.

Next step was to remove as much subjectivity as possible from the testing.
This was made much easier by an aeroplane that had no tendency to crab or pull to either side on take-off.
The test protocol was the following:
1. Load Aeroplane into simulator.
2. Start Engines and go to Chase view.
3. Set the Speed Display at the top of the screen.

4. Use Full Engine Power for acceleration until Aeroplane reaches 95 knots.
5. Bring Engines to Idle.
6. Apply Full Brakes when Speed drops to 90 knots while starting Timer.
7. Stop Timer when Speed drops to Zero.

Here is where things get interesting:
Braking Factor of -32768 went from 90 to 0 in 11.31 Seconds
Braking Factor of -1 went from 90 to 0 in 6.56 Seconds

OK, So far, so good, but I was a bit disappointed that the Negative values that allowed a flip didn't allow as much control as the Positive values.
I figured that as long as I had a working protocol, I should also see how the Positive values compared.
There was no point in testing the value for Braking Factor Zero since it was pretty much no Brakes at all.

Ready for this?

Braking Factor of +32767 went from 90 to 0 in.... 11.31 Seconds

Hey! Wait a minute!

If the greatest Positive Braking Factor is only equal to the weakest Negative Braking Factor is there something here we are not seeing? This is where I started seeing a lot of Neon signs lighting up.

Here is a little explanation on the most common way that computers represent SIGNED Integers in Binary:
(Skip if you already know this.)

Zero is simple in a 16 bit number (Extra Spaces added for Clarity.) (I am representing this as a Big Endian)
0 000 0000 0000 0000

One is (Just add 1 to Zero)
0 000 0000 0000 0001

Negative One is (Just Subtract 1 from Zero) (Note that the first bit here is the sign bit: 0 for Positive, 1 for Negative.)
1 111 1111 1111 1111

The Largest Integer 32767 is
0 111 1111 1111 1111

The Lowest Negative Integer -32768 is
1 000 0000 0000 0000

Now if we still have a 16 big number but treat it as an UNSIGNED Integer, we can only represent numbers from Zero to 65535.
If we use the same bit patterns we had earlier:
What we thought was Zero remains Zero.
What we thought was 32767 remains 32767.
What we thought was Negative 32768 now becomes Positive 32768 which is pretty close to 32767.
What we thought was Negative 1 now becomes Positive 65535.

What this leads me to believe is that the value we thought was a 16 bit SIGNED Integer with range -32768 to 32767 is really an UNSIGNED Integer with range 0 to 65535.

The testing thus far has pretty much convinced me, but I still need to do a few more experiments.

Good Night.
- Ivan.

 

[Ivan]

A Design Study

Here are some screenshots from a design study that seems to be the natural follow on to the P-38 EJ Lightning. There is nothing shared between the two projects other than the subject matter.

The problem here as usual is that my build method tends to be very expensive in polygon count.
he EJ Lightning finished at 762 polygons. Just what you see here is already at 168 poluggons and with a pilot and some interior equipment will probably be close to 300 polygons.

Dunno if this will ever end up as a full aeroplane. The budget will be pretty close.
The shapes are still kinda cool though.

- Ivan.

 

[papingo]

pollugon?

dear Ivan...
what is a poluggon?
papingo

 

[smilo]

it's smilo, not Ivan,
my guess would be,
a poluggon and a polygon are one and the same.
except, they are spelled differently.
which was, most likely, caused by fast typing
and limited proof reading before submitting the post.
that, or it was a test to see if anyone was paying attention.

 

[Ivan]

As good explanation as any

Sorry Papingo,

I ran the word together a bit.

It should be Pol-Ug-Gon: A really Ugly Polygon.

Actually the count is now up to 172 poluggons now. I did a LOT of editing on the back side of the canopy to make it a bit more tapered and have the lines match up a bit better.

I figured the P-38 might run for a while, so I started another thread.

Hi Smilo,

I was actually fairly certain there wasn't anyone actually paying attention here any more.

- Ivan.

 

[smilo]

yeah, i know what you mean.
don't get discouraged...
easier said than done, right?

remember, there are still a few interested in cfs1.
they just don't say much. it is what it is.
for example, if you look at your p-38 design study thread,
the view count is already over 80 views.
it's not earth shaking, but, it's not bad at all.

 

[womble55]

I fully concur, just because we are quiet doesn't mean we are not here. I was always told (many many times) to be silent when the teacher is speaking.
Some stuff we already know but an awful lot is new ground for us and undoubtably fires our enthusiasm for CFS1 and AF99. The annoying thing is though the incredible abilty you have to point out the blatently obvious that the majority of us hasn't seen.
please please please keep the reports coming

 

[Ivan]

CFS Audience

Thanks Womble55.

If your "blatently obvious" comment was about the Braking Factor post, I think now that it SHOULD have been blatently obvious. It makes so much sense now, but a week or two ago, I never would have thought about it.
Incidentally, there are a couple typos in that post as well, but I don't have the ability to go back and correct things. I believe the meaning is pretty clear in any case regardless of typos.


Hi Smilo,

Working on stuff for CFS1 does get pretty discouraging at times. The tools are still pretty lousy even though I believe that Hubbabubba and I have come up with a bunch of tools and work-arounds.

I don't really think the audience is all that big though:

Look at the download count for the Richard Osborne Me 109E. I believe it is still in single digits which makes me wonder if the time spent on it was worthwhile. The only thing I can say is that I learned quite a lot about an aeroplane I wasn't very interested in.

Regarding the P-38 Design Study, there may be 80 views, but I believe it is around 20 people who have each visited it 4 times. I know at least 3 of the views are mine from when I visit the thread to post something new.


Hello Papingo,

I am glad that someone is actually calling me on mistakes I made. I still can't figure out how I managed to corrupt the word "polygon" so badly. I don't suppose my 30 second excuse of an explanation about "Ugly Polygons" convinced anyone, but it sounded good at the time and we all KNOW that I don't make mistakes, right?

;-) to a most gracious audience.
- Ivan.

 

[smilo]

just to let you know,
as moderator, i have the capability to edit posts.
for example, check the first post in this thread.
i just did a little experiment.
notice the color of the hyphen in front of Ivan.

i don't believe it is my place to correct grammar or spelling.
certainly, not from Mr D in High School English Class.
that said, if there is something you would like edited,
please, let me know and i will fix it for you.

some comments about the me109e;
first, i, personally, like this model...a lot.
i intent on replacing the stock 109e with yours.
one of these days, i'll work on european theater textures.
but hopefully, a better artist will do it first.

second, i notice that it has only been uploaded here.
true, the download count is very low.
consider that the 109e project had no specific thread
and there was no download link provided when completed.
(other than the link i just provided above)
keep in mind that the 109e is now being buried in this thread.

at the risk of getting my butt in a sling,
i have to say that i believe the download library is....cumbersome.
i have no doubt that for those that use it often, it's great.
for me, there's just to much navigating...okay, i'm lazy. so?

i prefer the free flight site for downloads and, for that matter, uploading.
simply put, it's easy to use. the left panel menus are a breeze.
for example, in the past year, hubba's w7 joystick patch
has had 49 downloads here and 418 to date at his free flight site page.
(not to mention, over 5,100 hits since july at the aac forum)
and then, the ar196 just broke 500 at the free flight site.
what this tells me is that there is still a cfs1 community.
people are interested, just not as many as before and not so "vocal"
might i suggest sending a copy of the 109e to Dave.
i'm sure he would be happy to add it to your page there.

 

[Ivan]

Best Combat Flight Simulator Sites

I have to admit, No Dice's site is one of the best ones around. As you said, it is easy to navigate.
I can still remember the days when the downloads HERE were measured in thousands and often tens of thousands. I suppose the multiple crashes and generaly library weirdness cured all that.

My only real disappointment was that the Me 109E wasn't really one that I was interested in and I only reworked it because I thought there was a lot of interest. The downloads for my other projects here are also somewhat disappointing but that doesn't bother me much because I built those mostly for my own interest. The "for my own interest" is also why I haven't finished up a few other fairly worthy projects. They have reached a stage where they satisfy my own interest but haven't quite reached a release quality stage yet.

My plans are not to post the Richard Osborne Me 109E over at No Dice's site because this project really isn't mine.
That is same reason I haven't uploaded the Eric Johnson P-38J. Perhaps I will upload that one if my own -J Lightning project fails.

- Ivan.

 

[Ivan]

Lightning Flight Model

Update on the P-38J Flight Model:

The straight line performance wasn't all that difficult.
The Level Maximum Speed is pretty close.
The Absolute Ceiling is a little bit off but close enough.
The Compressibility effects are pretty much what I am looking for.
There is no significant Engine Torque Effect.
The Roll Rates are pretty close.

The general handling was based on my own guesses as to how the Lightning would behave.
I finally found a pretty comprehensive description of how the P-38 handled.
It turns out I guessed wrong on just about EVERYTHING.

From Tommy McGuire's crash, I had figured that the stalls would result in a very quick wing drop.
Turns out that a level stall is very gentle and only results in the aircraft gently mushing.
The recovery is uneventful with little altitude loss.
Although the Roll Rates are as documented, apparently there is a serious lag between the control deflection and aircraft response.
The Longitudinal Trim also does not change much with varying airspeed.

One other very odd thing I found is that often the engines run at slightly different RPM as can be seen by the Propeller Animation.

Seems like there is still plenty to tune after working on a Visual Model.

Happy Thanksgiving Everyone!
- Ivan.

 

[papingo]

papingo ect

my dear Ivan....
in my opinion you should put
the Osbourn 109/trop on your
page and an .mdl with non tropical
air filter for each to use as 'texture'
practice for us who aspire....
*******************************
***staircase prob.****
this bit is hard to put into words...
suppose you get a white 256x256 picture.
draw a black line across it then SKEW it say
at 2 degrees (such that the left is higher than the
right) then process it with this GIMP prog. so that
we have a line to 'analyse' or even reshade .
we maybe able to paste it into our textures
coz I notice that the staircase effect happens at
low angles off of the cardinal points!
TA-TA papingo

 

[Ivan]

Anti-Aliasing?

Hello Papingo,

I am not sure I understand your meaning. Are you asking me to demonstrate the technique I was describing about Anti-Aliasing?
If so, I can tell you that although the idea will demonstrate pretty well, it won't work all that well in overlays or shading an existing camouflage pattern.
The reason is that although I can using the technique with GIMP to anti-alias a single line so that it looks well, it doesn't create a "pattern" that can be used as an overlay. (At least I don't know how to do it.... Yet.)
The big problem is thata CFS uses a palette for colours instead of a 8 bits for each of the Red-Green-Blue colours. That means that you can't just "shade" an existing colour a bit darker.

There IS a method of reworking an image, but it is very labour intensive to the point where I have never wanted to prove that it works. I described in in the last post on the subject.

Regarding the Richard Osborne Me 109E Trop:
It is in the plans to re-build it with a non-tropical filter
It is not high on the list of priorities.
The difference between Tropical versus non-Tropical isn't much, so any paint scheme that would work on the Trop will pretty much work on non-Trop.
I have no plans on uploading it elsewhere. I basically did the rework as a favour for a friend.
I have already spent more time than I wanted to on it and won't be revisiting it very soon.
Download count isn't my goal. The audience it was intended for already knows where to find it.

I actually have done LOTS of modifications of others' projects for friends who have requested them.
Some are simple flight model or damage profile changes.
Some are SCASM hacks to fix a visual model or texture mapping.
Some are major rebuilds in AF99 as this Me 109E Trop was.
This is just the first one I have made available on a public site.
Quite a few of them are rather cool looking aeroplanes and I still have them installed on my machines but they will probably never be seen on a public site.

I don't have a "My Page". No Dice's site hosts some projects I have built or parts of them. It isn't really my page.
Note that almost none of the projects are in the form I released them.
They contain my visual models and flight models repackaged with a bunch of pieces by others.

Regards.
- Ivan.

 

[aleatorylamp]

Curtiss Wright AT-9 Jeep

Hello,
Thanks to Ivan for the invitation to join the thread. I´ve been browsing through it and it´s very interesting and varied. AF99 is one of my favourite hobbies and I see there´s ample activity here!

Even though I build for FS98, my planes import directly into CFS1 with no problems, so I may have a little something which to entice the appetite, namely a Curtiss Wright AT-9 Jeep, also known as CW-25. I´ve just welded the joints on the pieces of the difficult upper and lower nacelle components (rounded surfaces are my nightmare), and I may have glitched the fuselage, which has come out too wide and should be either narrower or higher - I´ll have to measure it better. For the time being, anyhow, here are some screenshots with provisional plain metallic textures. I don´t know when it will be ready, but it´s on the conveyor belt.

Another question: Should old biplanes like perhaps the Twin-JN, the Hansa Brandenburg G.1, the Airspeed Ferry or the Porokovschikov Bicoque (a twin-tail collapsible Russian pusher prototype built in an appartment on the 6th floor!!) tickle anyone´s fancy. I could gladly provide the AFX if anyone wants to further tweak them for CFS1.

Cheers,
Stephan