Chapter: 13. Miscellaneous Features

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Chapter: 13. Miscellaneous Features

13.01 Introduction

Here you will find features of Piano that are not covered under other major chapter headings, as well as descriptions of various shortcuts, options, and useful hints.

13.02 Unit Systems

The 'Select Units..' item (see 'Misc' menu, keyboard equivalent Command-/) lets you choose between the 'metric' (International) system or the 'imperial' (U.S./old English) system. It is also possible to mix the two systems, for example by specifying masses to be in kilograms and altitudes to be in feet. You can save your preferred settings, which will then be restored whenever you start Piano.

The 'Swap Units' item (keyboard equivalent Command-4) is a useful shortcut that lets you 'toggle' quickly between the current combination of units and the opposite set, whichever this may be.

Within Piano's parameter dialogs (see Chapter#08section05 ) you can simply click on the name of the parameter's units to display the alternative choice. This is a local action - it does not affect your global unit settings. (Note: If you click the 'set to default' button within such parameter dialogs, you may notice a local change in units. For example, mass-per-pax is set to 95 kg. This is only to avoid roundoff, since parameter defaults are metric).

Your global choice of units will be reflected in all input features and output reports. There is one significant exception: The definition of engine data matrices. Engine data files (ratings or sfc/fuel flow files) expect altitudes to be always in feet. Also, the secondary parameters in engine 'description' files (e.g. emissions data) have their own fixed units. See Chapter#07section03 through to Chapter#07section12 for details on engine data.

Unit conversions 'as you type': You can use the 'Conversions...' item (see 'Misc' menu) as a fast calculator for common units. Use the <Return> key to start a new number.

13.03 Picture Modes and Layouts

Picture windows created by Piano normally have a temporary existence: They close themselves as soon as you click anywhere on them, or as soon as they get covered by another window. This is very convenient if you only need to examine each graph or drawing at the time when it is created. If, on the other hand, you want to keep several pictures open indefinitely, you should set the 'Picture Modes' to 'Retain' (as opposed to 'Discard') under the 'Misc' menu. After that you can close each window individually via the red close-button at its top left-hand corner. It's easy to switch between the 'Retain' and 'Discard' modes quickly through their keyboard equivalents Command- = and Command- - .

If more than one picture window is open (in 'Retain' mode), use the <Tab> key to toggle between the two front-most windows in turn. This is very useful for visual comparisons. You can create any two graphs, for example two polars, and then repeatedly flick from one to the other. Use the '#' menu to first bring those windows that interest you near the front. If there are more than two windows, use the <Space> bar to rotate between all of them in sequence. (When each picture is essentially the same but for different values of some design parameter, this gives a hypnotic movie-like effect).

Pictures take up a near-maximum square area on your screen, and as a consequence they will cover each other up. You can use the 'Tile Arrangement' option to re-size all pictures and arrange them in a tiled pattern so they are all visible at the same time, without overlap. This has the keyboard equivalent of Command- Option T . To blow a picture back up to its original size, first select it, then click the green zoom-button near its top left corner. If you want to undo the tile arrangement for all pictures and re-stack them on top of each other, use 'Undo Tiling' (keyboard equivalent Command- Shift T). Alternatively, hold down the Option key whilst clicking the green zoom-button of any one picture window.

It's often very useful to be able to point anywhere on a graph or picture and obtain the local coordinates. If you hold down the Control key and click on a picture, that point's x-y position will be shown near the top of the window. If you hold the Shift key and click, it will be output in the main Piano window. Accuracy is of course influenced by your screen's pixel resolution.

You can enable or disable the automatic numbering of pictures (the counter will be reset to 1) through the 'Number Sequentially' item.

The 'Get Picture Info' feature shows the time of creation of any picture window and the values of recently-used parameters at that time. You can also change the title of the picture. 'Get Picture Info' operates on the front-most window, and the easiest way to access it is to Option-click anywhere on the picture.

Aircraft three-view drawings (see '3-View' under the 'Report' menu) have additional options for controlling their appearance, scale, colors, etc. Details are given in Chapter#03section17 .

If you find your view blocked by a window that you don't want to close, here is another useful tip: You can push any window behind all others (to the bottom of the '#' menu), if you hold the Option key and click on the name-stripe at the top of the window.

13.04 Printing Text and Pictures

You can print any text directly from inside Piano (see 'File' menu). Note that if you close the main Piano window, it is automatically replaced by a fresh one. You can use that to selectively produce only particular reports for printing. Otherwise the main window will contain the entire text output produced since the beginning of your session.

To print pictures, you first need to save them through the 'Save' item under the 'File' menu. You can then manipulate, export, or print those files through the built-in 'Preview' application or any other graphics tool.

You may prefer to Copy (Command-C) pictures and Paste them (Command-V) into a graphics tool. There is an 'ungroup' command within some such packages that lets you separate the picture into its constituent parts. You can then do just about anything to that picture.

13.05 Comparing Files

The 'Compare Files..' item under the 'Plane' menu makes a text-for-text comparison of the differences between any two 'plane' files within the same folder. This is useful for keeping track of changes made to derivative planes generated from the same baseline. Only the input parameters are compared, not any differences in performance or other characteristics. (All 'vital' and 'disturbed' parameters are kept in file; if Piano does not find a parameter in one of the two files, it shows its default setting or the word 'calculable'). See also Chapter#08section06 .

13.06 Comparing Planes

The 'Compare Planes...' feature under the 'Report' menu lets you generate detailed tables of comparisons between any number of planes kept in the same folder. This involves loading each plane in turn and evaluating its geometry, aerodynamics, mass, ranges, ceilings and other performance details, as chosen from the dialog that Piano displays.

Although this is a powerful feature, it can only make 'fair' comparisons between similarly-configured aircraft. Normally, each plane will be analysed 'as is', according to the data held on file. This means that it is up to the user to:

- Use similar or representative 'range mode' settings.
- Use similar allowances and reserve rules.
- Adjust the airframe and engine prices, if known.
- Use the same cost method including fuel price and other DOC parameters.
- Use similar takeoff elevations and Delta-ISA settings for field performance.

There are various options in the 'Compare Planes...' dialog that let you define common settings for these cases. You can also specify a common 'values' file to override temporarily some of the parameters held in the plane files. (To create a 'values' file, use the palette as explained in Chapter#08section04 ). This is convenient for defining standard fuel reserves and/or DOC rules. It makes little sense to assign common values to other parameters that will change the mass or aerodynamics of the original designs. Common settings are only applied during the comparison. The original planes, as stored on file, are not affected.

The tabulated results of comparisons are shown in a separate window. They can be saved to a file (using 'Save As...') in a tab-delimited format that can be read by a spreadsheet.

The 'Compare Planes...' feature needs to load several planes in sequence, and your current design at the end of the comparison will correspond to the last plane in the list.

Sample Plane Comparison

 AIRCRAFT              	Fokker F100 option     	Fokker F130 option  	Fokker F70 option      
 ENGINE                	Medium-BPR Fan late80s 	Medium-BPR Fan '90s 	Medium-BPR Fan late80s 
                       	---------------------- 	------------------- 	---------------------- 
 Span          (feet)  	      91.95            	     102.00         	      91.95            
 Length        (feet)  	     116.40            	     136.80         	     101.25            
 Fuse.length   (feet)  	     106.63            	     127.03         	      91.47            
 Fuse.width    (feet)  	      10.83            	      10.83         	      10.83            
 Seats Abreast         	          5.           	          5.        	          5.           
 S.trapez.     (sq.ft) 	       1006.           	       1190.        	       1006.           
 W/S           (psf)   	         97.           	        109.        	         83.           
 Ref.Thrust    (lbf)   	      15100.           	      20500.        	      13850.           
 T/W                   	      0.308            	      0.315         	      0.330            
 MTOW          (lb.)   	      98000.           	     130000.        	      84000.           
 OEW           (lb.)   	      54102.           	      70250.        	      49984.           
 MLW           (lb.)   	      88002.           	     113004.        	      78999.           
 MZFW          (lb.)   	      80999.           	     104681.        	      72000.           
 Fuel Volume   (USG)   	       3387.           	       4850.        	       3531.           
 Max. Payload. (lb.)   	      26897.           	      34431.        	      22016.           
 Design Payld. (lb.)   	      21466.           	      27485.        	      15800.           
 Design PAX            	        107.           	        137.        	         79.           
 Design Range  (nm)    	       1596.           	       2374.        	       1437.           
 Cruise Mach           	      0.707            	      0.739         	      0.691            
 Block Time    (hrs)   	       4.37            	       6.02         	       4.05            
 Block Fuel    (lb.)   	      17647.           	      27267.        	      14026.           
 Cash/trip       ($)   	      10175.           	      15452.        	       8396.           
 Ownership/trip  ($)   	       3005.           	       5196.        	       2417.           
 DOC/trip        ($)   	      13180.           	      20648.        	      10813.           
 DOC/seat-nm  (cent)   	      7.716            	      6.349         	      9.523            
 TOFL         (feet)   	       5895.           	       6756.        	       4919.           
 LFL          (feet)   	       4604.           	       4933.        	       4181.           (kts)    	        130.           	        139.        	        127.           
 All-Eng.Ceiling (ft)  	      35532.           	      35531.        	      35532.           
 Max.payld. Range (nm) 	        997.           	       1651.        	        662.           
 Fuel limit Range (nm) 	       1614.           	       2383.        	       2136.           
 Zero payld Range (nm) 	       2071.           	       2987.        	       2419.           
 Mission @ 500. n.miles, Design Payload. 			
 Block Time    (hrs)   	       1.68            	       1.61         	       1.71            
 Block Fuel    (lb.)   	       6530.           	       6994.        	       5777.           
 Cash/trip       ($)   	       4826.           	       5533.        	       4225.           
 Ownership/trip  ($)   	       1345.           	       1683.        	       1173.           
 DOC/trip        ($)   	       6171.           	       7216.        	       5399.           
 DOC/seat-nm  (cent)   	     11.534            	     10.535         	     13.667            
 TOFL         (feet)   	       4572.           	       4755.        	       4033.

13.07 Flags

The 'Flags' menu (under the 'Plane' menu) serves as a convenient short-term storage area for temporary design points, like a virtual 'plane' file. Simply use 'Set Flag...' (keyboard equivalent Command- Option F) at any time to mark the current design. This reduces the need to save lots of intermediate working files during the development process.

You can set a maximum of 15 flags, naming each one as you wish. After you reach this quota, the oldest flags start to 'fall off' the end of the menu. More recent flags are preserved automatically when you quit and restart Piano.

If for any reason you want to delete a flag from the list, you can do so by holding down the Shift key and selecting that flag. (The same trick works with planes listed under the 'Revert to Plane' menu). To clear all flags, hold down Shift and select 'Set Flag...'.

13.08 Updating of Dialogs

The 'Update Dialogs' item (under the 'Misc' menu) determines the initial settings displayed in certain dialogs. Piano may show different choices after the current plane is redesigned or after a new plane is loaded. For example, the 'Ceiling At...' dialog will initially display the MTOW. If you input a different value in this dialog, but later change the MTOW, there is ambiguity as to which of these two the dialog 'should' display the next time around. Some users may prefer their original input, others the new MTOW. You have the following (self explanatory) options for 'Update Dialogs':

- Always after Redesign (the default setting)
- Only after 'Load Plane'
- Never

Several dialogs are involved, such as 'Drag Spot', 'Ceiling At', 'Climb To', 'Cruise At', 'Descent From', 'Mission @Mass', and 'Flight Envelope'. Whatever your preference, it is always a good idea to check your input in any dialog before hitting 'OK'!

13.09 The Airports Database

Two databases of International airports are available under the 'Airports Data' item (see 'Misc' menu). These contain longitudes, latitudes, elevations and main runway lengths. You can find 'Great Circle' distances between any locations. Airports data are not kept up-to-date or guaranteed. This feature is merely a handy reference for range requirements. The first database has about 900 locations, and the second one ('Airports+') has more than 6000 but excludes runway lengths. You can adjust the existing data or add more airports through 'Edit Airports'.

The Airports dialog includes a 'globe' button that displays a simple world map. Click anywhere on the map repeatedly to show the distance between your last two clicks, or click outside it to close the window. The 'local' button shows airports located near your current selection (from the first of the two columns displayed).

13.10 The Tools ('T') Menu

The Tools (or 'T') menu contains some informal 'extras' or 'unsupported features' for expert users. You can skip this section if you prefer.

The following may be of interest to anyone familiar with Lisp: 'Apropos' retrieves information about Lisp functions or other expressions from a given sub-string in their name. The 'Search Files' option is a general-purpose search facility, and 'List Definitions' can be used to show all the definitions within a file containing source codes, assuming one is currently being shown.

The 'Load..' facility allows you to access some features of Piano that are experimental in nature. These vary with each release but may include:

- 'all plane notes' and 'pics & tests', which show relevant information by sequentially running through all planes in the current plane folder.

- 'compare calcs to notes'. This looks at any text inside the 'notes' of planes following the words TOFL, LFL, or range, and compares it with the corresponding calculated values. Such a simplistic approach is clearly not foolproof.

- 'opti demo'. This is a simple two-dimensional demonstration of the working principles of the optimiser.

- 'remove safety limits'. This should NOT be attempted under normal circumstances. It will remove a variety of restrictions built into Piano in terms of parameter limits and applicability of equations. It is highly likely that subsequent results will be nonsense. Normal service will only be resumed if you quit Piano and start it again.

- 'run 3-parameter study'. This produces a parametric study with one extra parameter compared to the normal 2-dimensional 'parametric study' feature. Results will be output in a similar tabular format, but cannot be plotted.

- 'update current planes dir'. This should only be used by long-time users (if advised) to update the contents of a 'planes' directory to the latest Piano standard.

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