Miscellaneous Speed-Hydroplane


Overview: Computes the speed at which a tire will hydroplane using published formula under various (input) conditions.


Entry into Module:


This module of the program is normally entered by clicking on the REC-TEC block in the upper left of the REC-TEC Window causing the drop-down menu to appear. Place the cursor on the Miscellaneous block and click on Speed-Hydroplane on the sub-menu to initiate this module.


Under certain circumstances, the user may choose to use the Files block instead of the drop-down menu approach. Selecting any file with an .H2O extension in the Dialog box accessed from either the Open Single File or Open Multiple Files block opens this module.


Selecting AutoLoad [ON] from either the Setup Menu or the AutoLoad Icon on the upper right side (third line) of the REC-TEC Window automatically loads the scenario that was on the screen when the module was closed, either individually, or when the program was closed. With AutoLoad [OFF] on the main REC-TEC Window, modules will start without loading a file.


Data Entry:


This module contains the following data entry blocks within the leftmost frame:


Speed - Hydroplane


              Air Pressure (PSI) Tire Air Pressure (PSI) Navin: (Range 16-36 PSI)


              (Button) Normal Wear

              (Button) Bald Tires


              Aspect Ratio Tire Footprint (Width/Length) Navin: (Range .6 - 1.4)


If Aspect Ratio Unknown Use


              Width Width of Tire Footprint


              Length Length of Tire Footprint


If Length Unknown Use


              H. Diameter Horizontal Diameter of Tire


              V. Diameter Vertical Diameter of Tire



Entry of required information in the data boxes is sufficient to generate a solution and causes output information to appear in the Output frame. As the input data is changed, the output data is automatically updated without the need to tell the program to update the output.




The output from this module consists of the Air Pressure, Tire Tread Type and Aspect Ratio plus the speeds for all of the included formulae expressed in the primary and secondary configurations.


Included Formula:



o A/C Spin-Up

o A/C Spin-Down

              Horne (Truck)

              Horne (Linear-Car)

              Navin (Linear)


              Speed: - Hydroplane Speed (Primary)

              Speed: - Hydroplane Speed (Secondary)




Several Command Buttons appear in a frame located at the lower right corner of the module Window. The Command Buttons allow the user to engage options including the option to Open and Save the data required to generate the scenario shown on the screen at the time the file was saved.


              Open .H2O File Calls up a Dialog box, which Opens any pre-existing .H2O file and displays the output results.


              Save .H2O D File Calls up a Dialog box, which Saves data on the screen to files with any user-selectable filenames. This is independent of the automatic saving as LastFile.H2O of the data at the close of this module or the close of the program.


              Formulae Opens a word processor (set by the user in Setup) with a file showing the basic formulae used in this module of the program. While the user may add to or modify the information in this file, it does not change the formulae imbedded into the program.


              Formulae* - Toggles a frame displaying the formulae for computing the unknowns in this module. In addition to the basic formulae, the frame shows intermediate steps with the actual input data shown in the computation.


              N This button toggles a graphical number pad on the screen that can be used to enter data into the input boxes without using your keyboard number pad. This may be useful for presentations as data entry can be accomplished using a wired/wireless mouse.


              Iteration / FD Analysis Calls up a frame that permits the user to input the minimum and maximum values for selected input variables along with the interval for Iteration. If Finite Difference Analysis (FDA) is selected, the resulting analysis computes the uncertainty level for the specified range of the input variables.


For a more in-depth description of Finite Difference Analysis, see the Finite Difference Analysis Section of this Manual Press [F2] from any Active module of the program.