Analysing and modifying the AFX file with QBasic.

[Ivan]

Hello Aleatorylamp,

Your 170 Gallon Fuel Load is NOT a typo.
It happen to be the Fuel Load of the P-39C.
Substituting Self-Sealing Fuel Bags (6 per side) in place of the single plain Tank per side reduced the capacity to 120 Gallons for the P-39D and later models until they were reduced even further to save weight.

A field modification to a 20 mm Hispano is actually a pretty good possibility if you should choose that option.

The 1250 pounds I suggested is actually the difference between Empty Weight and Zero Fuel Weight in the AIR file.
It does not include Ammunition or Fuel but includes some amount of Engine Oil. I don't know if this is a reasonable percentage of the Oil Capacity because I haven't compiled notes for the later series E6 Allison yet.
This is also making a few assumptions because equipment and armour varied between models.
I believe to be consistent, it should be a bit more than the 1250 pounds.

I would strongly suggest you list some of your itemized weights that you stated earlier that you were reluctant to list.
I can tell with the numbers that you have posted that there are some errors in those numbers but I can't tell where the errors are....
I can tell you very simply that the Empty Weight of my P-39D/F is several hundred pounds lighter than your P-39D-2 but the loaded weight even without Bombs is heavier than what you came up with, so there is either bad math or incorrect numbers somewhere.

Hey, perhaps my own numbers are incorrect?

- Ivan.

[aleatorylamp]

Hello Ivan,

Thanks for your offer in helping to discover my possibly incorrect numbers and/or maths errors.
It will definitely save going in circles...

I was going to post the list of weights for the flight plan for my model, but given the varying numbers to be found everywhere, I don´t know how precise they can be.
I know it´s difficult to define anything without any concrete numbers, so I was in the process of preparing a couple of possibilities for the Airacobra P-39D-2.

This one would be for a -D2 model with:
1 x 37 mm cannon,
2 x 0.50 cal. nose guns,
No wing guns.

Spec. Empty weight: 5646 lb (although the hand-written spec. sheet states 5626.8 lb)
Spec. Normal load : 7650 lb
Spec. MTOW: 8300 lb

Empty:.....................5646 lb
Gear oil: 2 USG..............15 lb
Pilot + parachute..........160 lb (although I´d prefer this to be 300 lb)
37 mm Cannon:............213 lb
2 x 65 lb Nose guns:.....130 lb (0.050 cal.)
...............................-------
Dry weight:...............6164 lb

Fuel: 104 USG:............624 lb
Engine Oil: 12 USG.........90 lb (Use 15 USG fuel in air file as this is consumed)
..............................-------
Loaded Weight...........6878 lb (without ammo)
Ammo:.......................160 lb (30 rounds for cannon and 2x200 rounds for MG)
..............................-------
Operational Weight.....7038 lb

This is what I thought was a bit on the light side, although it would certainly make a nimble fighter! With the alternative, perhaps better 20mm Hispano Cannon possiblity I´m also pondering, this would be 62 lb lighter - even more nimble!

I´d expect armour to be included in the empty weight, so that wouldn´t warrant any extra weight. If it´s too light, perhaps one should increase fuel, pilot weight or something...

Cheers,
Aleatorylamp

P.S. ...and here´s the armament data I was afraid would be a bit boring:

Guns, cannon and their weights:
-------------------------------
37 mm. M4 Browning Autocannon:
213 lb., 2000 fps, 150 RPM.
Ammo: 30 rounds x 1.99 lb (1.34 lb projectiles + 0.16 lb gunpowder + 0.49 lb shell)

20 mm. HS.404 Hispano Motor Cannon:
151 lb, 2800-2900 fps, 600-700 RPM.
Ammo: 60-round cartridge: 22 lb in total.
HE round: 0.57 lb including shell. Projectile: 0.29 lb. Explosive filler: 0.21 lb.

0.50 cal. AN/M2 Browning nose MG:
65 lb., 2910 fps, 750-850 RPM:
Ammo: 200 rounds. Cartridge: 0.25 lb. Projectile: 0.1 lb

0.30 Cal. AN/M2 Browning wing MG:
31 lb, 2800 fps, 1200-1400 RPM:
Ammo: 1000 rounds. Cartridge: 0.06 lb, Projectile 0.024 lb

Combinations without wing guns:
-------------------------------
A) One 20 mm. cannon and two 0.50 cal. guns:
would weigh 151 + 130 lb = 281 lb
Ammo.... 60 lb and 100 lb = 160 lb.
.....................................-------
......................................441 lb >>>>>> here I had a maths error: It´s not 341 lb!

B) One 37 mm. cannon and two 0.50 cal. guns:
would weigh 213 + 130 lb = 343 lb
Ammo.... 60 lb and 100 lb = 160 lb.
....................................--------
......................................503 lb

Saved weight taking away wing guns:
4 x 0.30 cal. Browing Wing MG 4 x 31 = 124 lb.
Ammo:..................... 4000 x 0.06 lb = 240 lb
..................................................-------
.................................................. ...364 lb

Cheers, and thank you very much again!
Aleatorylamp

[Ivan]

Hello Aleatorylamp,

I just posted a page from the P-39Q-1 Operating Manual which should give some better numbers.

I can tell you offhand that the weight of your 37 mm Cannon is quite a bit low.
The number I have been seeing is 238.4 pounds for just about every listing for the gun.
Where did your number come from?
The same applies to the .50 Caliber cowl guns.
Your weight might be correct for the bare gun, but there is some other equipment required for actually using the gun.

If you do the calculations for cowl guns and 47 mm cannon ammunition, I believe you will come up with a number about 30 pounds heavier than the number you have been stating.

There is also a table of armour weights if you want to try to do some calculations yourself.
Armour is NOT included in the Empty Weight of an aircraft.

By the way, the firing rate you have for the .50 Caliber M2 is for a free firing gun.
The synchronized gun will be firing a LOT slower.

- Ivan.

[aleatorylamp]

Hello Ivan,
Thank you for your comments.

There are several different pieces of data for just about all the specs concerning the four types of guns. It would be easy if I knew something about fire arms other than the pellet air-pistol I have.

There are several different sources giving sometimes consistent and sometimes indifferent information on a given caliber, there being several pieces of information regarding weight, rpm, fps, cartridge weight, projectile weight, explosive weight, links, containers, etc., etc., no doubt depending on details like when it was manufactured, what type of weapon it is, and where it is mounted - perhaps on an anti-aircraft land battery, a ship, a gunboat, a plane, an armoured car, a tank, a tripod, a jeep, or hand held.

What I will do is to calculate it from the other end: The 7650 lb operating weight.
Subtracting fuel, engine oil and ammo will give the .air file dry weight. Fuel and oil go into the tank and ammo goes into the Dp files.

Here´s the new Flight Plan:

Operating Weight:....7650 lb:
Fuel and oil:.. minus - 714 lb. 624 lb fuel, 90 lb (12 USG) Oil, (15 USG equivalent in fuel)
............................ -----
............................ 6936 lb. (dry weight with ammo).
Ammo:
Minus 60lb + 100lb.....- 160 lb (30 or 60 cannon rounds, + 2x200 rounds for 0.50 MG)
.............................------
.............................6776 lb
+ 100 lb for
good measure:...........100 lb
.............................-------
Dry weight
in .air file.................6876 lb

This would also tally with your recommendation of adding 1250 lb to the empty weight that I had in my .air file before.

Then, the 30 or 60 cannon rounds´ weight would be defined in the Dp files depending on the cannon chosen.

So, that would be it! End of problem.
Cheers,
Aleatorylamp

[Ivan]

Hello Aleatorylamp,

The number you arrived at is fairly reasonable, but the way you arrived at it is not entirely correct.
Here is why:

First of all:
60 pounds is correct for 30 rounds of 37 mm but
100 pounds for 400 rounds of .50 Cal is somewhat light.
The P-39Q manual lists 124 pounds for 400 rounds.
The P-39D itemized weights list 129 pounds for 400 rounds.
Yes, ammunition weight changed a bit over the years.
I generally use the value that is reasonable for the period but realistically a couple pounds doesn't make much of a difference.

Now keep in mind that your "Operating Weight" is an arbitrary measurement.
You are assuming Normal Loaded Weight includes full Oil capacity but it does not.

What we are really looking for in this case (at least in CFS) is the "Zero Fuel Weight".
I figure the user can determine the Fuel and Ammunition load but doesn't really have much control over Engine Oil and other fluids.
Because of this, I normally assume 1/2 to 2/3 Engine Oil is included in the Zero Fuel Weight in the AIR file.
Coolant, Hydraulics, and in this case Reduction Gear Oil would be at full capacity at all times and not be expended during the flight.

At Take-Off with full internal Fuel and Ammunition, the weight will be slightly low (about 1/2 Engine Oil capacity weight low).
When completing a mission and returning with no Ammunition and minimal Fuel, the weight will be slightly high by a few pounds because folks don't tend to use up all the Engine Oil. (That would be bad!)

Even with this method, we probably won't get exact numbers but we will get pretty close to where they should be in my opinion.

I hope this makes sense.

- Ivan.

[aleatorylamp]

Hello Ivan,
Thanks for your fast answer, and for the info on the correct 124 lb for the 0.50 cal. rounds.
That now increases the 0.50 cal. ammo weight in the Dp file from 4 to 4.96 oz per round.

So, technically this means a reduction of 24 lb to the 6876 lb Dry weight in the .air file, but judging by your comment that the Dry Weight is now fairly reasonable, and that the way I had arrived at it was not entirely correct, I would expect that this should now NOT be changed.

Regarding the non-consumption of your proposed partial engine oil tankage in "Zero Fuel Weight", the weight discrepancies at takeoff and on return after a mission could be avoided by including the oil in the tanks as equivalent in fuel.

This would come at the price of a different inaccuracy, of course, namely a falsely extended range, which would probably be worse than what you are proposing. But wait! One could always define a 15 USG equivalent of 12 USG of oil as non-usable fuel in the fuel tanks.
How about that? Or better: Using 2/3 of the oil weight here, it would be 10 USG equivalent in fuel.

So left and right tanks would have 65 instead of 60 USG of fuel each, and there would be 5 USG defined as unused fuel in each tank. Now, the only inaccuracy would be that the engine oil tank would always be 2/3 full.

Anyway, using your proposal for engine oil:
"Overload" oil capacity is 12 USG i.e. 90 lb, and "normal" is 8 USG, i.e. 60 lb, so technically, 30 or 40 lb of the oil would be added to the Zero Fuel Weight, but I won´t alter that, for the reasons expressed above - as you said the Zero Fuel Weight I had was fairly correct.

Thank you very much for your help and attention - now the weight calculation for my model is far more realistic.
Cheers,

[aleatorylamp]

Hello Ivan,
I was missing one point, namely the weight reduction due to the elimination of wing guns.

To benefit from this loss in weight, the 7650 lb Operating Weight would have to be reduced
by 364 lb, to account for the absence of the 4 wing guns and their 4000 rounds of ammo.

364 lb would be have to be subtracted from the Zero Fuel Weight, so we would be left with an Operating Weight of 7296 lb instead of 7650, and a Zero Fuel Weight of 6512 lb instead of 6876.

I wonder if this sounds reasonably correct...
Cheers,
Aleatorylamp

[Ivan]

Hello Aleatorylamp,

I don't think your 7650 pounds "Operating Weight" includes a full 1000 rounds per wing gun.
Let's put it this way yet again: My much lighter P-39F weighs more than that with full fuel and ammunition.

I have been trying to tell you that the "Operating Weight", Normal Loaded Weight and such for the Airacobra are not necessarily meaningful numbers. That is why it too a lot of poking around to find out what WERE meaningful numbers.

If I were you, I would take the Empty Weight, add 1250 pounds and then subtract the weight of 4 x .30 Caliber MGs and enter that into your AIR file. If you get your DP file correct and Fuel capacities correct, the rest should fall into place
(....but for the errors in my estimate of 1250 pounds)

THIS IS WHY I SUGGESTED EARLIER THAT YOU NEEDED TO PIN DOWN A LOT OF NUMBER FIRST.
It is pretty late in the game to be doing what you are doing now because you are bound to be back to performance tuning after this.
http://www.sim-outhouse.com/sohforum...=1#post1144505

- Ivan.

[aleatorylamp]

Hello Ivan,
OK, of course... Thank you.

Pinning down meaningful numbers for all sorts of different pieces of data for many different aspects of an airplane is far easier said than done for me, for the reasons I have been mentioning again and again for a number of weeks now, and which I will not repeat yet again.

And no, I don´t need another argument, thank you very much. The link you just posted does not help in this sense, even if it illustrates your point, but it also illustrates mine. Also, your comment preceding the link is totally superfluous.

I know you endlessly repeat the need for research and data collection, so you don´t need to insist so often. All I can say is that I do what I can, as far as I can understand, and I am grateful for the information you let me have.

It repeatedly comes to a point that makes me question the benefit of this occupation. It is supposed to be fun, and not a pain. I think I´ll take a holiday from this activity after I finish my corrected version of the Airacobra, unless I stop before, and forget about it.

So, back to the point: 1000 x 4 rounds would then classify as "Overload" as well, and "Normal" would more likely be 800 or 750 rounds per gun. The weight to be discounted for the removal of guns and ammo would then be between 48 and 60 lb less than the 364 lb I had before. I guess about 300 lb should be fine.

Curiously enough, I had done my performance tuning with too much ammo (the wing guns were still on), too much fuel (170 USG), and too little Dry Weight in the .air file, as you know. In fact, I originally had it at 5441 lb, even lower than the 5626 lb I mentioned yesterday.

Anyway, the resulting total weight of that combination was very nearly the same as it is now, after the new weight adjustments. I did some quick performance tests one or two hours ago, I have established that performance needn´t be corrected. That is quite lucky.

So tomorrow I can continue with the Battle of the Bleeds.
Cheers,
Aleatorylamp

[Ivan]

Hello Aleatorylamp,

My apologies.
I suppose I am pushing too hard.
We really have quite different goals for this project.

Last night I was working on edits to the drawings I plan on using.
It turns out that the ones I selected are actually not significantly better than the ones by Paul Matt, so perhaps I will be using both sets of drawings. I started looking at a Transparent Canopy and what I would need to construct it.
I believe this version will be built by Eyeball estimates rather than actual measurements.

- Ivan.

[aleatorylamp]

Hello Ivan,
OK then, not to worry.

I´m glad that the drawings are usable after all.

I measured the basic reference points for the canopy at the ends, top, and bottom, and then the top and bottom width of the thick central metal frame part, and finally the door height and width.
All else is eyeballed, and worked out OK.

So, good night!
Aleatorylamp

[Ivan]

Hello Aleatorylamp,

Quite a few drawings are useable.
It is just a matter of which ones are better. I believe the Polish Monografie drawings are better but for a print copy to mark up, the Paul Matt drawings look nicer.

- Ivan.

[aleatorylamp]

Hello Ivan,
Ultimately, it will be more a matter of how well AF99 allows a shape to come through.

I´ve been negotiating the exhaust bleed business for quite a long time this afternoon, and it is very difficult because everything is in Bory Main in this area. The mid-fuselage section is glued to the left and right wingroots, and there´s nowhere decent to glue the exhausts to. For the moment, they are in Inner Wing Mid Left/Right, with the obvious problem that wingroots portrude below and are in Body Main.

Do you remember the Japanese tin toy-airplanes? They had their exhaust manifold drawn onto the nose sides. It wouldn´t be the first time I´d do it this way in AFD99 either. Properly shaded and drawn onto the fuselage-side texture-bitmap, it even looks quite 3D.

Cheers,
Aleatorylamp

[Ivan]

Hello Aleatorylamp,

I don't think the Airacobra has such a difficult shape. (Famous last words!)
Except for the Nose Gear, everything looks pretty straightforward.

As for the Exhausts, I haven't gotten there and I don't know that I will at the end.
For me, messing around with Eric Johnson's AFX is mostly a matter of procrastination and playing around without really doing anything.
It is a chance to experiment with a few ideas and test a couple assembly sequences to see how they look before working on the project that really matters to me.

I was looking at my version of the EJ AFX and don't see the Wing Root / Fillet bleeds that you were chasing.

Last night and this morning, I started working on a Transparent Canopy.
Actually what I was doing was really the Canopy Frame rather than the Canopy, so nothing is really transparent yet.
I ended up having to do minor modifications to the Mid Fuselage Component and will likely do a lot more to prevent bleeds.
At the moment, I am having some difficulty convincing one of the Pilots that he should fly the P-39D.

Here is a screenshot of the first test to see how the pieces fit.
The problem here is that my Eyeball did not really line up well with the existing textures, so I will probably do some minor changes.
Yes, there is no Glass at the moment, but it is very simple to do; It is just a matter of connecting the dots in most places.
I will certainly need to create a new texture file for the Canopy Frame, but I will probably need new textures for the Flaps as well, so it isn't such a big deal.

- Ivan.

[aleatorylamp]

Hello Ivan,
No, I agree, the Airacobra is not a difficult shape, and the cockpit, as you say, is not difficult either, of course.

What I meant was more with reference to the small differences on different source drawings, which one can decide to follow or not, depending on one´s own criteria, but which ultimately also depend on how well or how practically a given shape can be depicted in AF99, or how visible these small differences come through, or if they are worthwhile. I didn´t mean that they were complicated shapes.

From your screenshot, it looks like your canopy is making good headway.

I also notice the 2D pitot-tube spur shows up correctly on your display. Mine filled in the front-upper part. I think it´s the modern Open GL graphics that can´t do some old things that the old 3Dfx graphics were better at. The new ones obviously have better capacity for other things, although these would be unused in CFS...

Regarding the mid-fuselage/exhaust subject:
For the moment, have you kept the original wing-fairing / wheel-well distribution?
I remember you said that there didn´t seem to be much point in having the wings as upper and lower component halves, but that apparently didn´t include the fairings.

It didn´t seem to be working very well before, so I put the fairings as single components into Body Main, glued to the mid fuselage, and then put in a Wing/Fuselage template on the wing joint. The result is that everything works, except for the exhaust bleeds through the wing seen from underneath. Exhausts, as I said, are still in Inner-Wing Mid L/R.

Now I got the idea of dividing the mid-fuselage into top and bottom sections. This way the fairings can continue glued to the bottom one, and the exhausts can be glued to the top one.

If this doesn´t work well, I´ll revert to the original build-distribution of the belly parts in Gear Centre and see what other maneuevers are possible.

Update: It worked! ...which I was more or less expecting. Now there are some remaining interactions between the pilot and the fore- and aft upper-cabin metal, but this should be curable with correct glue-sequencing.
Here are some shots. ...I still have to fix the "Siniy Krug" to fit the "Krasnaya Zvezda" more correctly... and the three "fives" in the registration number, which I noticeably made out of upside-down "twos".

Udate 2:
I noticed that the oblong shaped exhaust component could perhaps be improved by slanting the fore and aft ends, rounding off the cross-section on the outside, adding 2 extra panels, and enhancing the texture bitmap shading. This may well improve to the aspect of the 6 exhaust ports on each side of the mid-fuselage. At the moment it´s not finished yet, so I´ll post a picture when it´s done.

Cheers,
Aleatorylamp

[Ivan]

Hello Aleatorylamp,

Following your posts can be quite difficult at times. You tend to make a lot of edits to your posts.
What I saw this morning and what I see now are quite different, so I am not even sure what I should be responding to.

I figure if the drawings are accurate, I can do my best at representing the shape.
Most of the time, drawings are not so accurate. In this case, each set of drawings has its own problems but the Monografie set looks to be more accurate in general.

I also notice the 2D pitot-tube spur shows up correctly on your display. Mine filled in the front-upper part. I think it´s the modern Open GL graphics that can´t do some old things that the old 3Dfx graphics were better at. The new ones obviously have better capacity for other things, although these would be unused in CFS...

The Pitot shows up correctly on my screenshots because I fixed it.
If you look closely, you will see that the shape has been changed as well.
As I have stated a few times before, our goals are different. I am not really trying to fix everything on this model. I am doing my best NOT to alter the shapes of the original unless I feel like I need to. If I fixed EVERYTHING that I saw as incorrect, there would be NOTHING left of the original. ....and it would still be someone else's model and not really mine.
That is why I am just using it to test ideas.

Regarding the mid-fuselage/exhaust subject:
For the moment, have you kept the original wing-fairing / wheel-well distribution?
I remember you said that there didn´t seem to be much point in having the wings as upper and lower component halves, but that apparently didn´t include the fairings.

I rebuilt each Outer Wing into a single Component.
The Lower Wing Group proved to be the cause of many problems so I removed everything from it.
The Main Gear Wells had a lot of bleeds, so I rebuilt those and tacked them in place with Glue.
The Wing Fairings (Upper) are still in the Inner Wing Groups.
The Belly pieces include the underside of the Wing Fairings and seem to be a reasonable solution though they do have problems because they are in the Center Gear Group.

So far, I haven't used much Glue on the Fuselage pieces but that is likely to change very quickly when I put in the Cockpit pieces.
I actually may have to rebuild substantial parts of the Fuselage in order for the Pilot and Canopy to fit without bleeds and I really didn't want to do that.

- Ivan.

[Ivan]

....Almost forgot:

Here is an update for the status of the Transparent Canopy.
The first screenshot shows the Canopy Frame only.
The second screenshot shows my attempt at creating another pilot for the Airacobra.
The goofy thing is that to get the shapes the way I want them, the Parts expenditure was nearly the same as for my regular Pilot.
The Messerschmitt Pilot just did not seem to fit as nicely as I wanted.
The third screenshot shows (more like Doesn't show) the Canopy Frame and Glass but hides the fact that there isn't even a Cockpit Floor. The P-39 is certainly not flyable in its current state.

- Ivan.

[aleatorylamp]

Hello Ivan,
Sorry about the edits to my posts, and I´ll try to reduce them. Instead of adding a comment in a separate post afterwards, I thought editing it would make it simpler, but I see it doesn´t, so I´ll change my habit.

OK on the pitot tube - the spike is now added. I´ll have to do the same to mine, even if I have to glue it on!

Your model is looking very clean, I must say! ...even if we have different objectives!

At the moment, what is left of the original model is just about only in the wings... and even if it is not completely my model, I don´t mind. Naming whose model I´ve re-worked, is no problem for me either.

When I was re-shaping the lower fuselage to make the curvature stonger, I saw that the lower fairing halves in Gear Centre and the wheel-wells weren´t doing such a good job there - the inner parts of the wells never went black. So, I joined the top and bottom fairing halves and grouped them differently.

Many things went better, especially with the extended gear seen from underneath, but brought along a chain of consequences that took a lot of fixing, one of which was that the exhaust could no longer be grouped where it was.

Now it seems fine, but depending on how it goes on inside the cockpit, I may revert the simpler, previous grouping. I´ll see.

At the moment I´ve rounded off and textured the exhaust component a bit better, so it won´t look like such an oblong. I know the benefit of this is debatable, but it does look a little more rounded off now, and with the shading on the textures, I´m trying to separate the images of each exhaust port a bit, so I expect it will have been worth while.

I´ll try and not edit this post later... I just did now to chage some prepositions.
Cheers,
Aleatorylamp

[Ivan]

Hello Aleatorylamp,

The reason the edits were bothering me is because I browsed this thread with a mobile device fairly early in the morning to see if you had replied. I wasn't about to answer on the mobile though. Typing is very slow and screens are small.
When I came back later, the post was quite different and it any consideration about the earlier post wasn't useful any more.

I just finished doing some edits to the Nose section and the front of the Mid Fuselage section to eliminate an intermittent bleed that was happening there. There were a few polygons that were not even close to planar. That section will need to be cut up for a new Component for the Cockpit area.

I believe you must still be using the Mid Fuselage texture for your new Canopy Frame. I was getting the same kinds of patterns earlier.
It might be a good idea to copy that particular texture file to a new one. I called my new file Canopy.pcx but of course any name will do. If you do that and fill in the window areas of your new file with regular paint, the Canopy Frame will look less distracting.

My Canopy Frame seems to be amazingly expensive in terms of resources. Many Parts needed to be triangulated because they were displaying when they should not. Are you having the same problem? It appears that some of your Canopy Frame is visible out the front window.

- Ivan.

[aleatorylamp]

Hello Ivan,
I think you´re right about edits. As a post is editable for 6 hours, I thought it was more practical to include corrections or additions by editing it, instead of adding further small posts later, which would in turn also make it cumbersome to answer to.
Both ways have their drawbacks. The only really good solution is to space out posts more, with more concrete, final information, less speculation, and less volatile information, i.e. without writing about developments in "real time", as it were.

In my case, some nose section panels needed triangulating after splitting the cross-section from 8 into 12. Some were severely corkscrewed. The area under the cockpit also needed extra parts for the transition between round to flatter.

Initially, I filled in the grey on the original cockpit windows, but kept the drawn cockpit frame lines on the texture, as a reference, as in your case, but it is not definitive yet, and all that area needs texture corrections as yet. As the texture spread covers the whole fuselage and canopy area, this area is quite workable, so I thought it wouldn´t really matter if the canopy gets its own texture or not. Also, a new canopy texture would of course not necessarily imply a complete re-map of all fuselage textures.

The canopy frame component halves are tagged as "Collection", so as to be visible from inside, and so that the opposite side can be seen through the windows from outside.

The drawback is that there are bleeds through the metal from the opposite side, from the front and from the back, which could be stopped by tagging it "Smooth", at the cost of the opposite side being invisible, of course.

In fact, it´s not only the frame that bleeds through, it´s the pilot´s body as well. That´s what I meant when I said "depending on how it goes on inside the cockpit, I may revert the simpler, previous grouping.". Now, I don´t know if a different grouping of the lower mid-fuselage area will leave more room for some decent glue sequencing in the cockpit or not. I´m still procrastinating here too!

Right now, the Canopy Frame has 14 parts per half - I tried to keep pieces planar, so none needed triangulating in my case. Perhaps it is a bit more rudimentary, but it all fits for the moment.

Well, the Battle of the Bleeds rages on.
Cheers,
Aleatorylamp

[aleatorylamp]

Hello again,
Here´s a compound screenshot of the new exhaust, which could be argued
as looking better, although perhaps not necessary!
Anyway - it´s a bit more rounded off.
Cheers,
Aleatorylamp

[Ivan]

Hello Aleatorylamp,

As usual, our purposes are different. One of my "Requirements" is that the original textures be altered as little as possible.
I want to be able to plug in any texture set that was done for the original EJ model and have it work.
That is why I am doing the Canopy Frame in another texture file.
Since that one did not exist in the original, I can alter it as much as I want.

I don't believe the original texture mapping is ideal and the naming of files is on the assumption that only one piece of the model inhabits each file. I believe I could do much better than that, but that gets into a texture remapping exercise which I hate.
I am already running into this problem with the Pilot.
I lifted the textures from the Me109E Trop even though the 3D model underneath is pretty different but there are enough alterations needed as to make the mapping job pretty tedious.... And I haven't even gotten to the Pilot's Shoulders yet.

There will be at least three (or four if you count the Interior Canopy Frame) items that still need to be textured, so it would be silly not to share the texture files between pieces.

Naming the File after a single piece of the model is misleading.
In the case of the Me109E, the Supercharger Intake shares the same file as the Pilot but the file is called Pilot.PCX....

Just as a comparison, my Canopy Frame has 23 Parts per side.
Actually each side only has 18 Parts, but the Left Component has 5 extra Right side Parts so there can be a slight overlap to avoid bleeds from inside the Cockpit.

Regarding edits to the model, I would strongly suggest that you review photographs of the real thing when working on pieces of the Aeroplane. Sometimes what looks reasonable in AF99 isn't reasonable when one considers how big the actual Part would be if scaled to real world dimensions. That applies to shapes as well.

Here are a few screenshots of my edits from last night.
The Canopy Glass has been removed so that the interior is more visible.
The Pilot's Head looks to be a bit too narrow still, and the fellow need to requisition a set of Goggles and a proper Uniform.
As a Company test pilot, he is fine, but Army regulations would need to be followed before this project is completed.

- Ivan.

[aleatorylamp]

Hello Ivan,
Of course... our purposes are different. In my case I have to alter textures quite a lot because of the re-adjusted shapes and re-positioned, re-grouped elements, but that was to be expected.

I also not only look at different sets drawings all the time, but constantly look for different details on all possible photos iI can find. Incidentally, I found an interesting Russian article by one of the pilot trainers on how early Airacobras were crated over from England, inventoried, assembled and used for training, and later models were flown over from the U.S. I also read that they sent back some of the cannon, to use their own ShVAK 20 mm ones wqith which they were more familiar, and that one of the reasons they really liked the Airacobra was that after landing flip-over accidents the pilot could come out unscathed, as opposed to a lump of flesh as happened on other models. Howevcer, the article didn´t go into any technical details.

Back to my headache: The canopy-frame, pilot´s head and body, and cabin floor are still causing bleeds. This is because the cockpit is sunk into the fuselage a little, so the front and back parts bleed. Then, the "floor" pieces, together make quite a concave shape, so I had them glued to partial cabin components, which seemed OK, but wasn´t perfect.

I suppose it would be safe to assume that the canopy-frame would be in Canopy-High Wing. Initially I had the Pilot there too, so that the cockpit "floor" parts could be tagged as insignia-above, but that still created problems with the angular parts.

On the other hand, if the canopy were also in Body Main with everything else, perhaps that would allow a decent glue sequence with slanted triangles between canopy halves and the head.

Thus, I would like to ask you, only generally, about how you would plan, at least initially, to group the parts for your transparent canopy.

Cheers,
Aleatorylamp

[Ivan]

Hello Aleatorylamp,

Of course... our purposes are different. In my case I have to alter textures quite a lot because of the re-adjusted shapes and re-positioned, re-grouped elements, but that was to be expected.

As it turns out, I may need to redo some of the texturing myself. The existing textures don't line up well with the new Transparent Canopy pieces. I CAN adjust the pieces to fit the textures, but I can see a distortion problem if I choose to do that.

I also not only look at different sets drawings all the time, but constantly look for different details on all possible photos iI can find. Incidentally, I found an interesting Russian article by one of the pilot trainers on how early Airacobras were crated over from England, inventoried, assembled and used for training, and later models were flown over from the U.S. I also read that they sent back some of the cannon, to use their own ShVAK 20 mm ones wqith which they were more familiar, and that one of the reasons they really liked the Airacobra was that after landing flip-over accidents the pilot could come out unscathed, as opposed to a lump of flesh as happened on other models. Howevcer, the article didn´t go into any technical details.

That must be a very interesting account. If you can flip a Nose Wheel Aircraft, then things must be bad.
If survivability in a Razorback Yak or Lavochkin is worse than the Airacobra when the aircraft flips, then life is REALLY bad....

I commented about the need to look at photographs because I noticed a couple errors in the Paul Matt drawings.
I actually included one of those errors in my own edits but now that I know about it, I will be sure not to include them in the actual project aeroplane.

I also noticed that the Canopy frame segments in your model appear to be much too narrow.
Look at the area of the Door and Door Frame.
There is both a Fuselage piece and a Door piece that come together.
My own estimate is that with two pieces coming together with a seam in the middle, the combined segment width is at least three or four inches which means it should be at least 0.25 feet across and probably much more.
Some of the frames appear to be much wider than that.

Back to my headache: The canopy-frame, pilot´s head and body, and cabin floor are still causing bleeds. This is because the cockpit is sunk into the fuselage a little, so the front and back parts bleed.

I believe I am actually getting a pretty clean assembly with no obvious bleeds at this point. (Arrogant, aren't I?)

I suppose it would be safe to assume that the canopy-frame would be in Canopy-High Wing. Initially I had the Pilot there too, so that the cockpit "floor" parts could be tagged as insignia-above, but that still created problems with the angular parts.

On the other hand, if the canopy were also in Body Main with everything else, perhaps that would allow a decent glue sequence with slanted triangles between canopy halves and the head.

Actually your assumption isn't "Safe". I actually have NOTHING in the Canopy / High Wing Group in my Assembly.
I am not really sure what you mean by "angular parts".
I found that my regular Glue sequence worked out pretty well with most of the major pieces in Body, Main Group.

Thus, I would like to ask you, only generally, about how you would plan, at least initially, to group the parts for your transparent canopy.
[

If you are only looking for a "General" description, then perhaps you might want to quit reading at this point.
This description is about to get pretty detailed with illustrations.
.
.
.
.
The First Screenshot shows the way that I sliced up the MidFuse Component into three pieces.
From the center section that I now call FuseMid, it is pretty obvious what was sliced off the front end and the back end.
The ends were sliced off into separate Components because each end had a section that created a concavity that was difficult to avoid. Note that this kind of concavity exists in just about all single seat Aeroplanes, so the treatment here is pretty similar.

The Second Screenshot shows what each side of the Canopy Frame looks like. This Component is CFrameL which is the Left side Canopy Frame. Note that this Component extends past the mid line with one extra Part at each frame segment thus it overlaps the Right side which also extends past the center line.
Note that I have posted Screenshots in the past that have the left and right sides coloured differently to show the overlap, but I can't remember which project this was for. I tend to use this technique for just about every project.

The Third Screenshot shows the GlueCFrameL Part which aligns with the Port side Cockpit sill on the bottom and the peak of the Canopy Frame at the top.

Hope this helps.

- Ivan.

[aleatorylamp]

Hello Ivan,
OK, very interesting! Thanks. Very explicit screenshots and descriptions.
Eliminating concavities by dividing the fuselage this way was one of the things I noticed would be necessary, and this re-arrangement was next on my list, after different other maneuevers of debatable benefit! It is also surprisingly simple, and accounts for the success you have had with it!

OK, I´ll study the matter and act accordingly, and also make the canopy spars wider!
By angular parts in the glue sequence I meant irregularly shaped triangular glue templates, placed at angles.

Very well!
Cheers,
Aleatorylamp