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Some of the email I've been getting indicates a real interest out there in Plane Maker, so I've decided to document the creation of my next aircraft project here, for those who wish to follow the process from start to finish. I should say, at the outset, that I don't claim to be an expert with the Plane Maker utility. I have so far crafted six aircraft, four of which I felt were good enough to offer on X-plane.org though far from the quality of some of the many beautiful models also posted there. In that regard, I'd like to acknowledge the help of the real experts who, daily, post on the x-plane tech news group and stand ready to assist anyone needing the answer to problems which crop up constantly as beginners attempt to use a complex piece of software without easy access to formal documentation or instructional material.
I say "easy access" because there is, in fact, a lot of instructional material to be found on the web for the use of both Plane Maker and World Maker, if you take the time to ferret it out. When time permits, I'll add links to some of the best of it here, to ease the search. For now, however, let's move on to building an airplane for X-plane 7.30. If you wish to duplicate the process, you will need a good graphics program that can handle layers and save in multiple formats such as Photoshop or Paintshop Pro. The tutorial will assume the use of Photoshop and that the user has at least basic skills with the software.
The plane we'll be modeling is Piper's J3 Cub, so the first thing we'll need is a good set of 3-view drawings to get the proportions right. The J3's been around since the forties and there's lots of reference material available. Web sites devoted entirely to the aircraft exist and literally thousands of photos and drawings are at our fingertips. In the end, though, what we need most is a good side and top view in bitmap format to use as background images in Plane Maker and a complete set of performance and general specifications to insure that the finished model looks and flies like the real one.
Paul Matt does the best 3-views available for a huge variety of aircraft. A CD is available containing data for the cub as well as several other aircraft of the era. The advertisement offers a sample 3 view of, happily, the J3 Cub! It can be found here and shows a dimensioned side view, a front view and sections. Right-click on the drawing and save it to disk. I sent for the CD ($25.00 U.S.) and in the meantime, pasted the sample jpg into Photoshop, cropped the fuselage to 1024x221 and saved it in 24 bit windows bitmap format. What you see below, is what you should wind up with, only bigger.
Make certain, when you save the bitmap, that it's no larger in any dimension, than 1024 pixels, or else Plane Maker will announce an error when you try to import it, quit cold and leave you staring at the desktop! When you save the image, save it to a new folder in your System 7.30>aircraft>General Aviation folder named j3Cub.
Before we get to use this hard-won image, though, there's a few other preliminary chores we need to do. Fire up Plane Maker and choose "new" from the File Menu if it's showing anything other than a blank startup page like this:
Get out your specifications and performance figures that you will have gleaned from the Paul Matt CD or other web sources, go to the "Standard" menu and choose "Viewpoint", which is first on the list:
Along the left hand side we fill in the V-speeds for the Cub, which are:
| Vso | 33 |
| Vs | 33 |
| Vfe | n/a |
| Vno | 61 |
| Vne | 106 |
| Mmo | n/a |
| PosG | 5.7 |
| NegG | 2.3 |
These speeds are in knots, which is the default. You can change it to mph if you wish; the selection box to do so is in the bottom section, 3rd column over; "speed units". Also please note that there is an item specific help popup that appears if you pause your mouse over any of the selection items.
Also on this page we can specify pilot viewpoint (top middle section, first column). For the Cub it will be :
| long arm | 5.0 |
| lat arm | 0.0 |
| vert arm | 2.0 |
These "arms" are dimensions, in feet, measured from a point which, as the popup window over such items constantly advises, "can be any point on the aircraft, but you always have to use the SAME reference point for ALL data you enter on the aircraft. The nose of the aircraft is a typical reference point."
In the same section, at the bottom in the second column over are two boxes labeled "view center x" and view center y". For the Cub, since it is tandem seating, view center x can be left at 512 pixels, which is the center of our 1024 pixel wide view and we'll enter the recommended 590 pixels for the view center y, which is the level of the horizon across the windshield in level flight. Move this up and down to suit your preference later, if you want a different height for your horizon level.
The last entries in this window are the selection boxes to include standard navigation lights and to "draw craft geometry from the inside in side views". They're in the very bottom group at the right side, bottom section. You can tick the box to draw outside geometry from the inside in front views as well, but I don't do this, as you get a back view of the spinner in ghost view if you do, which looks a little weird.
There's space at the top to enter your name as author, any aircraft notes you wish and a registration number of your choice. That takes care of it for this window, so you can close it out, go to the file menu and choose "save as". Navigate to your new J3 folder , fill in J3 Cub on the bottom line where the cursor's flashing and Plane Maker will create a brand new "J3 Cub.acf" file for you.
On the standard menu choose, now, the fourth item down, "engine specs" ; it has 3 tabs.
Choose the Engine 1 tab and in the top right section, fill in the engine data:
| max power | 65 | critical alt | 1000' |
| trans. losses | 0.01 | max man. press. | 28" |
| redline | 2300 | top of green arc | 2150 |
| idle | 600 | bottom of green arc | 1000 |
| spool time idle/full | 3.0 |
Move on to the Engine 2 tab. When you open it, only 2 selection boxes are visible, one labeled "1" and the other "0". Change the 0 to a 1 and a whole row of settings opens, dealing with the prop specs for this engine. You will see, then, that the top "1" selects reciprocating engines and the "1" you just entered selects a single engine aircraft with a fixed pitch propeller. This can be altered for other types, as can the number of engines. Needless to say, choosing "2" will open another column of prop settings for the other engine.
On the single column, move down to long arm and enter minus .35' (-0.35) which will be the location of the prop, just in front of the aircraft's nose. The entries for lat arm and vert arm can remain at the default 0.0 settings as can the settings for vert/side cant (engine centerline offset) since I don't have figures for these items as yet. Often some right thrust is helpful to counteract torque effect on takeoff, but that can be determined, empirically if necessary, later.
Further down, enter a prop radius of 2.9 feet for a 70" prop and root/tip dimensions of 5.0 and 4.5 inches respectively. Make certain you don't miss the decimal point like I once did and mistakenly enter .50 and .45 for these numbers. X-plane reacts extremely unpredictably when it gets off-the-wall figures like this. In my case the plane flipped over onto its back immediately after I opened the throttle; the sim sulked for a few seconds, then quit in a huff without telling me why. Trouble-shooting that one is a story in itself!
Skip over the min/max pitch settings (for variable pitch propellers) and enter a design speed of 2150 rpm which is the cruise rpm. Below that, is the PROP design speed of 85 knots, which is a guess at the windspeed through the propeller. This number can be altered later, if necessary, by outputting that data to the screen in X-plane test flights to find out what it really is. This number, together with the design speed rpm can be juggled to bring performance into line with the real-world Cub.
Leave the final setting at the default prop tip speed of 600 knots. All other settings can safely be left at the default settings as well, including everything on the third tab. Quit out of the Engine Specs window and save your work.
Final preliminary book work is is to enter the weight and balance figures, so select that window from the Standard menu. Which looks like this:
In the top right section locate the aircraft's CG. Scaling off our sample drawing, measure back from the 0 point at the nose to the 25% wing chord location, which will do for the default location: the center of the three figures to be entered. I make that to be 5.5'. Six inches fore and aft of that point locates the forward and aft CG limits at 5.0' and 6.0' respectively. These numbers agree well with the actual weight and balance data which I found elsewhere on the web. The vertical CG location can be a guess at -.5'; just below the center thrust line, which in the model is the vertical 0 point.
In the bottom right section enter an empty weight of 680 lbs, a fuel load of 72 lbs (12 gallons) and a gross weight of 1220 lbs.
Fuel in the Cub is carried in a single 12 gallon tank beneath the windshield area, above the pilot's knees. #tanks is therefore 1 and fuel ratio is also 1.0, since total fuel is carried in the one tank. Longitudinal location, measured from our side view for the center of the tank is 2.8' and 0/0 for the other arms. Quit out of this window and save your work.
We can now move on to actual design work, starting with the fuselage.
