Ivan's Workshop - AF99 Tutorial - C205 Veltro

Landing Gear

Hello All,
The drawings I have gave lots of useful measurements, but showed nearly nothing about the landing gear. With some projects, we would be left with guessing at the locations and sizes of the wheels, but in this case, another source provided precise dimensions: AeroDetail No. 15 covers the Macchi C.200, C.202, and C.205 pretty well. These books are written in Japanese mostly, but often you can still figure things out from the context. The C.200, C.202, and C.205 have many common dimensions. There are major airframe differences between the C.200 and C.202 (which some CFS designers didn't figure out), but not between the C.202 and C.205. In fact many C.202 Folgores were rebuilt to become the C.205 Veltro. One of the remaining surviving aircraft is such a plane.

There was another Italian language book I was able to find that also helps.

From this source, we find the follwing numbers:
Track - 3.00 metres (Distance between Main Wheels)
Main Wheel - 600 x 200 x 216 mm
Tail Wheel - 300 x 100 mm

Longitudinal and Vertical dimensions are scaled from the drawing. Problem here is that I don't know if the gear was extended or compressed by the aircraft weight.

Next step is to put those numbers into use.
- Ivan.
 
When faced with such a problem - missing parts in one set of drawings - I would "morphed" two or three (or more) plans into one, keeping the "good" parts of each plan for the final plan drawings I would use. The jeep is such a plan, incorporating at least 2-3 side drawings and even more for top and front-aft views.
 
Hi Hubbabubba,

Perhaps I wasn't clear in my description. The pieces of the aircraft were all in the drawings by Brioschi. The missing stuff was the labelling of dimensions. There are no dimensions at all in Brioschi's drawings. The dimensions are in the factory drawings or Tavoli. The problem is that I don't have but a small set of those, and I don't have any that label the tire sizes or landing gear track.

I could have measured and guess as I still have to do on other parts, but better yet is to have the actual specifications. I was guessing by eyeball that the main wheel was about a 600 x 175 or so. Turns out it is a 600 x 200 but because of rounding issues, it will be about a 597.4 x 195.

I basically did the morphing thing you described but with the pieces of ONE drawing. I will need to do that again for a Top View.

- Ivan.
 
Wheels

AF99 Projects are allow a maximum of 30 Components and 30 Structures. Components are much easier to use and have greater flexibility but are so limited in number that only essential pieces should be built that way. If a piece can be built as a Structure without seriously compromising appearance it should be built as a Structure instead of as a Component. Thus, I tend to build wheels as Structures even though they look like Rollers that Fred Flintstone would be using.

To Create a Tail Wheel (300 mm Diameter, 100 mm Width) we first import a 10 point Circle from the Storehouse.
We want the Wheel to have a flat instead of a point on the bottom to represent Weighted Tires, so Rework / Rotate - Pitch by 18 degrees (1/20 of a 10 sided Circle).

With the Propeller Blades, we moved a blade by picking a point with Rework / On Screen and Control-Clicking on the new location for that point.
In this case, with the wheel, we select a new location and since NO POINT is selected on our polygon, when we Control-Click, the CENTER of that part is moved to the new location (17.50A 0.05U).

The imported Circles are all 10 feet in Radius. To make the Tail Wheel the proper size, we resize in two steps. First step is to make it 0.1 x its original size. Then multiply by 0.49 to get the final diameter.

To make this into a Side Template for a Structure, Select Function / Template Side Structure. Save this as TGWheelSide.

Next, to create the Top Template, delete all but the forwardmost and rearmost points. insert two points in between.

Change to a Top View

Use the Point Editor to Rework points to be a Rectangle with vertices 0.16 Foot Offset from the Center Line. If you don't like the ordering of the vertices, Use Control-Y to cycle the points.

Select Function / Template Top Structure.

Save as TGWheelTop.

- Ivan.
 
More Wheels

To Create the Main Gear Wheels, follow the same process as with the Tail Gear Wheel Templates. The sizes and locations are different of course:

Center:
1.42F
4.35D

Radius: 0.98
Width:+- 0.32

There are a couple additional steps. Relocate the Side Template to -4.92 Feet (4.92 Feet Left) for the Left Side and Rework / Mirror it for the Right Side.

Note: For no particularly good reason, if I have a master part, it will always be on the Left of the Aircraft.

Note that after creating the Side Template, I always check for alignment between the top and bottom vertices of the circle. In the case of the TG Wheel, there were not differences noted. In this case, some of the top points and the matching bottom points did not match in their Fore-Aft location. Use the Point Editor to fix those.

Create a Structure Top Template for both the Left and Right MG Wheels.

Go to the Structures Shop and select a Rectangular Cross Section and put it at each vertex of the wheel. Manufacture, Save each of the three wheels.

Now that we have new pieces, Go to the Paint - Special Effects Shop and add each of the new pieces.

Produce.......
 
Hopefully We did not forget to change the default attributes before Producing the Project.

This first screenshot shows the whole missing plane in the simulator.

Next we see the fact that the contact points are wrong because at Dusk with the sun coming from very low, the shadows start before the wheels.

Use an AIR file editor to make some corrections to the Contact Points. The details are beyond the scope of discussion here.

After a couple tries, we get the Last screenshot with shadows appearing more or less correct.

Good Night.
- Ivan.
 
As I warned earlier, at some point we would have to work on a Top drawing for general reference.

I will be taking a few short cuts with this drawing because we are using it mostly for checks on the width of the fuselage at various stations. The location of these stations will be determined by panel lines rather than exact offsets. I don't believe there is a need to shift anything around to be an exact match to the factory dimensions.

Here is roughly a half scale version of this drawing. It was scaled from Mr. Brioschi's excellent plan view. To get here, we had to first rotate it 180 degrees to have the nose go the the left. (This is to match the Top View in the AF99 Parts Shop.) After that, to make the centerline of the aircraft be completely horizontal, I used GIMP to rotate this drawing by -45.07 degrees. (How did I get that number? By trial and error!) After doing that, I found that the spinner was skewed to the left by about 1 pixel. The rest of the drawing lined up pretty well.

Note that the Wing Fillet appears to line up very well with the firewall which seems to be a pretty good reference point for the aircraft.

- Ivan.
 
Making Templates

After Reworking the Top View, There is pretty much enough information to make Templates for the major parts of the aircraft. In this case, there was a bit of a problem though. The sizes and longitudinal locations of various pieces of the plane were not in agreement between the Side and Top Views. The Wings looked to be in pretty good agreement with locations in the drawing only a few hundredths of a foot off from one drawing to the other. The Asymmetry of the wings is actually in the Top View and is very close to the 200 mm in the real aircraft. The Stabilizers looked to be quite a lot off and bad enough not to be useable to measure points.

The next step was to scale a bunch of points from the Side View to create a Fuselage Template. (To do this, use Create / Datasheet and just enter the values for the points.)

The Stabilizer Templates were done by entering just the 4 points that seemed to line up with the Dimensional Drawings and drawing the rest by eyeball. From the Side View, the vertical location of the Stabilizer is determined to be at 1.50U. This is in line with the tip of the Tail Cone which will make the final build easier since it is at the widest part of the Tail Cone.

The Wing Templates are a bit more complicated. There are two parts on each side that need to be created: The Wing Fillet, and the Wing itself. Both parts are created as single polygons using the Create / Datasheet method to enter the points. The vertical location for the Fillets is easy to determine using the Side View.

The vertical location of the Wing is determined partially from the Side View as well. The Side View gives us three points: The Wing Leading Edge, The Wing Trailing Edge, and the Height of the Left Wing Tip (0.50U). We draw the three points in AF99 which gives us a straight line from the Wing ROOT Leading Edge to the Tip and a line from the Tip to the Wing Root Trailing Edge. (I saved this part in AF99 as X1.) The points of the Wing Template are then aligned vertically with the part X1 from a front view. In lining up the RIGHT Wing (shorter by 200 mm), I found that the height of the Wing Tip with the same Dihedral was only 0.45U.

I have found that there are very few real pieces of an aircraft that begin with the letters X, Y, Z, so I use these as prefixes for Template parts of various types. X Parts are those that are disposable. Sometimes an intermediate part can be used to build some other parts, but is not worth saving by itself. When a part is saved in AF99 with "Save As", it leaves its outline and vertices as a white outline. When building the next part, you can snap to a nearby reference vertex while in Rework / On Screen with the "P" key and cycle through points using the Space Bar. After a build, I usually end up with a bunch of X1....Xn parts which can all be deleted. Y parts are those that are useful references from one session to the next but not worthy of a proper name. When building the P-40C, I used a LOT of Y parts to check the alignment of the nose. I would adjust them from session to session to optimise the shape. Z Parts are ones I generate for use in AF5Paint as overlays. AF5Paint uses a 8.3 file naming format so often the reference part has to be named differently from the actual part in AF99.

After creating all the templates, putting them into an assembly in the Paint / Special Effects shop shows what the basic shapes of the aircraft will be as you can see in the attached screenshots.

Happy Memorial Day.
- Ivan.
 
Oil Coolers

Today, I went to go see the Macchi C.202 Folgore at the National Air and Space Museum. Outside temperature was in the mid 90's but it is only about a 10 minute walk from my office. The idea was to get an impression of what this plane really looked like. I took a few pictures along the way, but the lighting is generally pretty poor in this place. Looking at photographs or in this case, seeing the real aircraft will reveal things that are just not visible in a set of 3-View drawings. Except for a few detail differences, the C.202 is the same aircraft as the C.205 being built here. Quite a few C.205s were converted C.202s.

Now on to the build for today: Oil Coolers.
From the Side View, the dimensions of the Oil Cooler may be scaled. The Oil Coolers are ideal pieces to build with structures.

The Scaled dimensions are entered to create a Template Side Structure. In this case, the Template is left on the centerline because it will serve as the Side Template for both Left and Right Oil Coolers. When this part is finished (and saved as "Template Side Structure", it can ten be Rework / Rotate / Bank / 90 degrees to create the basic shape of the Top Template. It is reshaped slightly and then moved outboard to be even with the Side of the Nose as scaled from the Top View drawing. Save as function Template Top Structure as part OilCoolerTopL. Rework / Mirror the part to create a OilCoolerTopR.

Manufacture the Structures. Add them to the Aircraft Assembly in the Paint - Special Effects Shop. Note the GROUP Colour and the STRUCTURE Colour.

Produce and view the result in CFS. Note how the Colours of the new pieces match the Specifications in the Paint - Special Effects Shop? This isn't what you might have expected, is it? This technique is what I use for Gun Barrels.

Good Night.
- Ivan.
 
Shapes for Texturing

One thing I neglected to mention in the last post was that the Structure Cross Section I picked for the Oil Cooler was an Octagon. I believe that a Hexagon has vertices that are too visible. With such a small "Round" object, an Octagon makes sense. Note that there are TWO possible Octagons to choose from. One has a flat at the top and bottom and one has points at the top and bottom. In general, choose the one iwth points at the top and bottom. The reason for this is because if the object will be textured in the future, the points at the top and bottom will be the demarcatio between the Left and Right sides of the texture if it is being textured Left - Right. If it is being textured Fore - Aft, then it really does not matter so much.

If you create a piece for your aircraft with flats on the top, and then texture Left - Right, then the top of your new piece will have streaks on the top face. The pixel from one of the sides (I forget which side) will be smeared across the flat surface.

The same thing happens if the flat is on the bottom of the piece.

- Ivan.
 
Stations or Bulkheads

When I build a fuselage or nacelle in AF99, I typically draw cross sections for the piece in what I believe to be logical places. In a real aircraft, these would be called stations and numbered as an offset from the aircraft's datum point. I call these parts "Bulkheads" and number them as offsets from the Model's Center of Gravity. Folks may cringe at the terminology, but I find it to be useful that these parts are all grouped at the front of an alphabetically sorted list because it makes them easy to find.

The first and most obvious "Bulkhead" is between the Spinner and the Engine Cowling. Use the Parts Shop to create this Template. First bring up the SpinnerBack Structure as a "Reference Part". Next, put your mouse pointer approximately at the rear of the Structure and Right Click. That will center the display at that location. Next, Change to a Front View. Click on or near the vertices representing the Back side of the SpinnerBack.

After the last vertex is created, Select Rework / On Screen. As each point is highlighted with a small circle, Press "P". This will cause that point to snap to the nearest reference point. Use the Spacebar to advance to the next point. If you find that you have skipped a point, <Shift> Spacebar will cycle through the points backwards.

Save this new part as Type Outline (as opposed to Standard Application) with the name BulkF0763.afp.

Bulk means this is a Bulkhead Template Part. F says it is in front of the CoG. 0763 says it is 7.63 feet forward of the CoG.

Time for Bed.
- Ivan.
 
These Look Like Pieces but Are NOT

In the initial Assembly of the Veltro, There are three different "Groups" of pieces of the aircraft fuselage. The Nose (containing the Spinner, Propeller and Oil Coolers), The Body,Main (containing a Fuselage Template which is really just a reference part), and the Tail (containing a Tail Template, Stabiliser Templates, and a Tail Wheel).

The Fuselage Template extends into the Nose section. I like replacing only one piece at a time so that the shape of the rest of the aircraft can be used to check whether the new piece is proportioned correctly. I also like to retain the Fuselage and Wing Templates to use as a reference in the AF99 Parts shop. To do this, we need to split the single piece templates into smaller templates.

The TemplateNose part can be generated by taking the TemplateFuselage and deleting the extra vertices.

The TemplateFin part can be generated by deleting vertices from the TemplateTail part. Note that an extra point was added to match the bottom of the Rudder Hinge line because without it, the part would have a straight line between the forward edge of the Fin Fillet and the trailing edge of the Rudder.

It isn't obvious here, but there is a noticeable gap between the bottom edge of the rudder and the upper edge of the Fin Fillet area which can be seen in photographs.

I also chose to split off the TemplateCanopy part to prepare for the next step....

- Ivan.
 
Many cross sections of the Macchi C.205 Veltro and its ancestors look very much like simple ovals. Even areas of the aircraft that are not oval cross sections are fairly smooth curves.

I believed that it would be a good idea to attempt to approximate the Fuselage and especially the Tail Cone with structures which lets AF99 generate most of the smooth curves for us. The end result probably won't be exact, but it should be a pretty good visualization aid.

Using the TempFuselage part as a reference, we generate a Structure Side Template part that bears great resemblance to a long Banana. There are several points that are not specified in the TempFuselage part that we need to specify in the Structure Side Template: The points at the fore and aft edge of the canopy at 3.79A, 5.65A, and one within the headrest at 8.05A. Here we put in points which keep the curve looking smooth.

After saving the TempSide part, we Rework / Rotate / Bank / 90 degrees. Rework / On Screen and use the Space Bar to advance to the Tip of the Tail Cone. Note that it is mislocated vertically. Adjust with Control-Click to match the Side Template. Switch to a Top View and use Control-Click to relocate to match the Tips here as well.

Use the Point Editor to adjust the Side offset of each point to match the dimensions from the plan view from our reference drawing. Save this part as a Standard Application, NOT as a Structure Top Template. I called this part "TempTop".

Note: Structure Template parts do not work as reference parts in the AF99 Parts Shop.

Rework / Mirror the TempTop part. Rework / On Screen. Use the Mouse Pointer to position each point close to its corresponding point on the reference part (The White Outline non-mirrored part) and use the "P" key to snap the point to the corresponding point on the reference part.

NOW, save it again as a Structure Top Template.

Time for Dinner.
- Ivan.
 
Structures for Visual Check

Create Structures using Circle-12 point cross sections except for the Tip of the TailCone which is just a simple Point. The last cross section that was created can be deleted with the Backspace key.
 
After switching out the pieces built from the last few sessions, this is what we get. I think this looks pretty fair.

Next Step is to use these Structures to create the actual pieces that go into the Aeroplane.

- Ivan.
 
Fin and Rudder Component

In order to include a Tail Cone Structure, we had to take the TempTail Part and remove the area that represented the Tail Cone so that the pieces would not conflict in display.

The Original TempTail Part only had a poor and irregular outline, so we need to add a bunch more points to make the curves smoother and to have a few reference points for generating the actual Polygons we will use to build a Fin / Rudder component. I like to have the edges of the polygon correspond to the actual pieces of the aircraft. In this case I saw a slight problem. Our reference drawing and photographs of the aircraft do not agree. Look at the rudder balance area. The Balance goes much higher in the actual aircraft. Guess the outline will need to be done by Eyeball.

First step here is to add the lines we can be sure of. The Rudder Hinge, Balance, Top, Forward and Aft points are fairly certain. Next, add a few points to smooth out the outline.

After the TempFin part is saved, create a part to use as a reference for the width and taper of the Fin / Rudder. The Fin is 106 mm wide. This works out to an offset of 0.17 feet. The width at the top is unspecified, so set the taper by Eyeball. Note that the Red Circled points are the ones in the Fin Template that are givens. All the others are adjustable for aesthetics.

With the TempFin reference part and the FinL01 part, we have enough points to determine all the rest of the parts that go into the Fin / Rudder Component. FinL02 was created by clicking to create a point near where we want and then using "P" to snap that point to the closest reference. This method is quite easy. All the rest of the points were created in less than 5 minutes. Note that we only create the Left Side parts.

(What do we DO with those parts????)
 
Go to the Components Shop.

Take all the Parts we created in the last post and add them as Lef-Right Pair in the new Component. There will be a total of 30 Polygons. Save this Component as "Fin".

Go to the Paint / Special Effects Shop and add the new Fin Component to replace the original TempFin Part we used before. During this stage with all the new pieces untextured, I like to make Components "Sharp" so that the contours within can be easily seen as shadows.

Save

Produce

Go to CFS and look at the result. Notice also that I sneaked in a Nose Structure built the same way as the Fuselage and Tail Structures.

Good Evening.
- Ivan.
 
AF99 Basics

At this point, we have covered a lot of the basic mechanics of how to use the various "Shops" in Aircraft Factory 99.

The Parts Shop is used to create single Parts or Polygons.
They can be Pieces of the final aircraft, Templates for Structures, or Reference parts we will use to build other parts.

We have discussed using the Create Datasheet function to enter our original shape.
We have discussed clicking on the locations where we want vertices for the Part.
We have discussed using the Point Editor to precisely move a vertex of a Part.
We have discussed how to rework a Part "On Screen" to move a vertex.
We can cycle through the list of vertices by using either Spacebar or Shift Spacebar.
We have retrieved various Circles from the Storehouse.
We can move a part by moving its center with Control Click.
We can move a part by moving it by a vertex with Control Click.
We can center the screen by Right Clicking on a location.
We can Rotate a Part along an axis.
We can Magnify or Reduce a Part's size.
We can Snap a point to a vertex on a Reference Piece.


The Structures Shop is used to create Pieces with a known set of cross sections.
We have been able to use Top and Side Templates created in the Parts Shop.
We have picked cross sections from a list.
We can Manufacture a Structure and Save or Reject it.


The Paint / Special Effects Shop is used for Final Assembly.
We have added various pieces of the aircraft.
We can change the colours of the pieces.
We can set display conditions such as "Landing Gear Down" for a piece.
We can set characteristics of a piece such as "Sharp" for a Component.


There is a fair amount that has not been covered up to this point and even a couple shops that have not been mentioned, but with these basics, we can build a fair number of pieces to a virtual aircraft.

- Ivan.
 
Adjustment to Fin

I wasn't quite satisfied with the shape of the fin, so added a polygon to move the bend in the center polygon back a bit. The exact location is a matter of aesthetics, but you can see what I used. The main idea was make the leading edge taper at the top no sharper than the leading edge at the bottom.

- Ivan.
 
Now that we have a Fin and a Tail Cone, we need cut an opening into the tailcone to match where we expect the Fillet connecting the two pieces should go. The reason for the need to cut an opening is that we don't want any part of a polygon behind the fillet. The basic principle is that Part A can't bleed through Part B if Part A isn't behind Part B.

There are two rows of polygons in the Tail Cone. The back row is easiest so we will start there. The front edge of the back row is intentionally even with the Rudder Hinge Line because that is where the Fillet will have a break in contour. All we have to do is start the cut about even with the rear edge of the Rudder and end it at the Rudder Hinge Line. The width at the Hinge Line is just a touch larger than the width at the widest part of the Rudder which is 0.17. The Fillet width here ended up to be 0.19 which seems to be the correct contour.

At the front row of the Tail Cone, there needs to be a break somewhere in the middle. In some other models, I would put an additional row of polygons and an additional Bulkhead there but it really is a waste of polygons for no real gain. The trick here is to create a reference point inside the Top Polygon of this row in such a manner that it is within the plane of the Part we are cutting into two.

Consider that if two points are in a plane, then a third point anywhere on the line connecting the first two points is also in that plane. This is the ideal mathematical case. Reality when using points that can not be any more precise than 0.01 foot means that sometimes the point in between doesn't really line up. If they do not line up, I prefer to skew the point in the direction that results in a Convex rather than Concave approximation.

- Ivan.
 
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